Author: "Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)" - Searchworks@Jio Institute Digital Library Search Results

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703 results on '"Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)"'

1. Tailoring cryo-electron microscopy grids by photo-micropatterning for in-cell structural studies

Author: Laurent Blanchoin, Manuel Théry, Julia Mahamid, Fabrice Senger, Mauricio Toro-Nahuelpan, Ievgeniia Zagoriy, European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany, CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut National de la Recherche Agronomique (INRA), EMBL Interdisciplinary (EI3POD) program under Marie Skłodowska-Curie Actions COFUND (no. 664726), European Project: 760067,3DCellPhase, European Project: 771599,ICEBERG, European Project: 741773,AAA, Physiologie cellulaire et végétale (LPCV), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Materials science, Ion beam, Cryo-electron microscopy, Green Fluorescent Proteins, Nanotechnology, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Biochemistry, Focused ion beam, Article, Pattern Recognition, Automated, Specimen Handling, law.invention, 03 medical and health sciences, 0302 clinical medicine, law, Image Processing, Computer-Assisted, Humans, Cell adhesion, Molecular Biology, 030304 developmental biology, 0303 health sciences, Cell Membrane, Cryoelectron Microscopy, Molecular biophysics, Cell Biology, Adhesion, Molecular Imaging, Characterization (materials science), Surface micromachining, Electron microscope, 030217 neurology & neurosurgery, Intracellular, HeLa Cells, Biotechnology, Micropatterning
Abstract: Micromachining by cryo-focused ion beam (FIB) milling coupled to cryo-electron tomography (ET) enables visualization of macromolecules directly inside cells. Yet, spatial control of cell adhesion on electron microscopy (EM) grids remains a bottleneck in the specimen preparation pipeline. This protocol describes a contactless and mask-free photo-micropatterning of EM grids for site-specific deposition of extracellular matrix-related proteins. We achieved accurate and reproducible cell positioning, leading to optimized preparations for cryo-FIB milling. We tested HeLa and RPE1 cell lines on various grid types (gold or titanium mesh coated with SiO2, gold or carbon films). Briefly, grids were passivated with an anti-fouling agent, followed by controlled ablation of the passivation layer, and further functionalization with fibronectin. The micropatterning procedure takes ~3 h. Employing micropatterning to produce complex shapes generated a predictable intracellular organization, allowing direct correlation between cellular architecture and in-cell 3D-structural characterization of the underlying machinery at molecular resolution.
Published: 2020

2. Force Production by a Bundle of Growing Actin Filaments Is Limited by Its Mechanical Properties

Author: Laurent Blanchoin, Jean Louis Martiel, Julien Berro, Alphée Michelot, Rajaa Boujemaa-Paterski, CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Dynamique Cellulaire et Tissulaire- Interdisciplinarité, Modèles & Microscopies (TIMC-IMAG-DyCTiM), Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525 (TIMC-IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), Department of Biochemistry - University of Zurich, Yale University [New Haven], National Institutes of Health/National Institute of General Medical Sciences Grant R01GM115636, ANR-14-CE11-0003,MaxForce,Maximiser la production de force: de la molécule au tissu(2014), Physiologie cellulaire et végétale (LPCV), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Dynamiques Cellulaire et Tissulaire - Interdisciplinarité, Modèles & Microscopies (TIMC-IMAG-DyCTiM), Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications Grenoble - UMR 5525 (TIMC-IMAG), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Quantitative Biology::Tissues and Organs, Biophysics, macromolecular substances, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Polymerization, Quantitative Biology::Cell Behavior, Protein filament, Focal adhesion, Quantitative Biology::Subcellular Processes, 03 medical and health sciences, 0302 clinical medicine, Rigidity (electromagnetism), Mathematics::Algebraic Geometry, Actin filament dynamics, Cytoskeleton, Actin, 030304 developmental biology, Mechanical Phenomena, 0303 health sciences, biology, Articles, Elasticity, Biomechanical Phenomena, Actin Cytoskeleton, Bundle, Formins, biology.protein, Filopodia, 030217 neurology & neurosurgery, Model
Abstract: International audience; Bundles of actin filaments are central to a large variety of cellular structures such as filopodia, stress fibers, cytokinetic rings, and focal adhesions. The mechanical properties of these bundles are critical for proper force transmission and force bearing. Previous mathematical modeling efforts have focused on bundles' rigidity and shape. However, it remains unknown how bundle length and buckling are controlled by external physical factors. In this work, we present a biophysical model for dynamic bundles of actin filaments submitted to an external load. In combination with in vitro motility assays of beads coated with formins, our model allowed us to characterize conditions for bead movement and bundle buckling. From the deformation profiles, we determined key biophysical properties of tethered actin bundles such as their rigidity and filament density.
Published: 2020

3. Lattice defects induce microtubule self-renewal

Author: Ariane Abrieu, Laura Schaedel, Laurent Blanchoin, Charlotte Aumeier, Manuel Théry, Denis Chrétien, Sarah Triclin, Karin John, Jérémie Gaillard, CytoMorphoLab, Physiologie cellulaire et végétale (LPCV), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Génétique et Développement de Rennes (IGDR), Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique )-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre de recherche en Biologie Cellulaire (CRBM), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), French National Research Agency (ANR) ANR-16-CE11-0017-01 ANR-12-BSV5-0004-01 ANR-14-CE09-0014-02 ANR-18-CE13-0001, Human Frontier Science Program RGY0088, European Research Council (ERC) 771599 741773, Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Centre de recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE13-0001,APERTuRe,Une nouvelle perspective sur la régulation des microtubules(2018), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut National de la Recherche Agronomique (INRA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Lattice dynamics, Dimer, [SDV]Life Sciences [q-bio], General Physics and Astronomy, Crystal structure, Self renewal, Instability, 01 natural sciences, Microtubules, Article, Lattice vibrations, 010305 fluids & plasmas, Quantitative Biology::Subcellular Processes, 03 medical and health sciences, chemistry.chemical_compound, Microtubule, Lattice (order), 0103 physical sciences, 010306 general physics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, Physics, Thermal forces, 0303 health sciences, Structural defect, biology, Chemistry, 030302 biochemistry & molecular biology, Model mechanisms, Dissipative dynamics, Dynamics, Tubulin, Lattice defects, biology.protein, Biophysics, Lattice structures, Passive materials, Defects
Abstract: The dynamic instability of microtubules is powered by the addition and removal of tubulin dimers at the ends of the microtubule. Apart from the end, the microtubule shaft is not considered to be dynamic. However recent evidence suggests that free dimers can be incorporated into the shaft of a microtubule damaged by mechanical stress. Here we explored whether dimer exchange was a core property of the microtubule lattice independently of any external constraint. We found that dimers can be removed from and incorporated into the lattice at sites along the microtubule shaft. Furthermore, we showed by experiment and by modeling that rapid dimer renewal requires structural defects in the lattice, which occur in fast growing microtubules. Hence long-lived microtubules have the capacity to self-renew despite their apparent stability and thereby can potentially regulate signaling pathways and structural rearrangements associated with tubulin-dimer exchange at sites along their entire length.
Published: 2019

4. Intermediate filaments control collective migration by restricting traction forces and sustaining cell–cell contacts

Author: Sandrine Etienne-Manneville, Nicolas Borghi, Mithila Burute, Shailaja Seetharaman, Chiara De Pascalis, Xavier Trepat, Batiste Boëda, Carlos Pérez-González, Cécile Leduc, Benoit Vianay, Polarité cellulaire, Migration et Cancer / Cell Polarity, Migration and Cancer, Centre National de la Recherche Scientifique (CNRS)-Institut Pasteur [Paris], Sorbonne Universités, Université Pierre et Marie Curie - Paris 6 (UPMC), Barcelona Institute of Science and Technology (BIST), Facultat de Medicina [Barcelona], Université Paris Descartes - Paris 5 (UPD5), CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Jacques Monod (IJM (UMR_7592)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Barcelona, Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), This work was supported by La Ligue Contre le Cancer (EL2017.LNCC) and the Institut Pasteur. C. De Pascalis was a scholar in the Pasteur–Paris University International PhD program and received a stipend from Fondation pour la Recherche Médicale, Institut Pasteur, and a short-term European Molecular Biology Organization fellowship. C. Pérez-González acknowledges support from Fundación Caixa. The France-BioImaging infrastructure network is supported by the French Agence Nationale de la Recherche (ANR10-INBS-04, Investments for the Future) and the Région Ile-de-France (program Domaine d’Intérêt Majeur-Malinf). The Nikon Imaging Centre is a member of the Agence Nationale de la Recherche Infrastructure France-BioImaging (ANR10-INBS-04), and the Institut Jacques Monod is a member of Infrastructures en Biologie Santé et Agronomie and Agence Nationale de la Recherche France-BioImaging (ANR10-INBS-04)., ANR-10-INBS-04-01/10-INBS-0004,France-BioImaging,Développment d'une infrastructure française distribuée coordonnée(2010), Polarité cellulaire, Migration et Cancer - Cell Polarity, Migration and Cancer, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), ANR-10-INBS-0004,France-BioImaging,Développment d'une infrastructure française distribuée coordonnée(2010), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: 0301 basic medicine, migration cellulaire, [SDV]Life Sciences [q-bio], filament intermédiaire, Intermediate Filaments, Astròcits, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, macromolecular substances, Cell Communication, Biology, Adherens junction, Focal adhesion, Nestin, 03 medical and health sciences, 0302 clinical medicine, Microtubule, Cell Movement, Report, Glial Fibrillary Acidic Protein, Animals, Vimentin, Cell migration, Intermediate filament, Cytoskeleton, Actin, Research Articles, Cells, Cultured, 030304 developmental biology, 0303 health sciences, Wound Healing, Migració cel·lular, Chemistry, Cell Biology, Plectin, Cell biology, Rats, 030104 developmental biology, Treadmilling, protéine, Astrocytes, vimentine, 030217 neurology & neurosurgery, Mesenchymal cell migration
Abstract: Using an in vitro wound healing assay, De Pascalis et al. show that intermediate filaments (IFs) participate in the dynamics of the acto-myosin network and its association with adhesions in astrocytes during collective migration. Glial IFs control the distribution of forces and the interactions between neighboring cells, ultimately determining the speed and direction of collective migration., Mesenchymal cell migration relies on the coordinated regulation of the actin and microtubule networks that participate in polarized cell protrusion, adhesion, and contraction. During collective migration, most of the traction forces are generated by the acto-myosin network linked to focal adhesions at the front of leader cells, which transmit these pulling forces to the followers. Here, using an in vitro wound healing assay to induce polarization and collective directed migration of primary astrocytes, we show that the intermediate filament (IF) network composed of vimentin, glial fibrillary acidic protein, and nestin contributes to directed collective movement by controlling the distribution of forces in the migrating cell monolayer. Together with the cytoskeletal linker plectin, these IFs control the organization and dynamics of the acto-myosin network, promoting the actin-driven treadmilling of adherens junctions, thereby facilitating the polarization of leader cells. Independently of their effect on adherens junctions, IFs influence the dynamics and localization of focal adhesions and limit their mechanical coupling to the acto-myosin network. We thus conclude that IFs promote collective directed migration in astrocytes by restricting the generation of traction forces to the front of leader cells, preventing aberrant tractions in the followers, and by contributing to the maintenance of lateral cell–cell interactions.
Published: 2018

5. Spatial integration of mechanical forces by α-actinin establishes actin network symmetry

Author: Laurent Blanchoin, Amandine Pitaval, Hajer Ennomani, Manuel Théry, Laetitia Kurzawa, Fabrice Senger, CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-14-CE11-0003-01,MaxForce, European Project: 771599,ICEBERG, European Project: 741773,AAA, Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), European Research Council (ERC) 741773 771599, French National Research Agency (ANR) ANR-14-CE11-0003-01, and ANR-14-CE11-0003,MaxForce,Maximiser la production de force: de la molécule au tissu(2014)
Subjects: Cell architecture, Retinal Pigment Epithelium, macromolecular substances, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Biology, Protein filament, 03 medical and health sciences, Symmetry, 0302 clinical medicine, Crosslinker, Extracellular, Humans, Actinin, Actin, 030304 developmental biology, 0303 health sciences, Network architecture, Crosslinkers, α-Actinin, Cell Biology, Actin cytoskeleton, Symmetry (physics), Actins, Actinin, alpha 1, Mechanical force, Biophysics, Alpha-actinin, Symmery, Mechanical forces, 030217 neurology & neurosurgery, Intracellular
Abstract: Cell and tissue morphogenesis depend on the production and spatial organization of tensional forces in the actin cytoskeleton. Actin network architecture is made of distinct modules characterized by specific filament organizations. The assembly of these modules are well described, but their integration in a cellular network is less understood. Here, we investigated the mechanism regulating the interplay between network architecture and the geometry of the extracellular environment of the cell. We found that α-actinin, a filament crosslinker, is essential for network symmetry to be consistent with extracellular microenvironment symmetry. It is required for the interconnection of transverse arcs with radial fibres to ensure an appropriate balance between forces at cell adhesions and across the actin network. Furthermore, this connectivity appeared necessary for the ability of the cell to integrate and to adapt to complex patterns of extracellular cues as they migrate. Our study has unveiled a role of actin filament crosslinking in the spatial integration of mechanical forces that ensures the adaptation of intracellular symmetry axes in accordance with the geometry of extracellular cues.This article has an associated First Person interview with the first author of the paper.
Published: 2019

6. Local actin nucleation tunes centrosomal microtubule nucleation during passage through mitosis

Author: Thomas Waring, Jannis Anstatt, Laurent Blanchoin, Louise Brown, Manuel Théry, Tobias Zech, Buzz Baum, Francesca R Farina, Nitya Ramkumar, Jessica Bithell, Giorgio Scita, Dureen Samandar Eweis, University College of London [London] (UCL), IFOM, Istituto FIRC di Oncologia Molecolare (IFOM), CytoMorphoLab, Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institute of Translational Medicine, University of Liverpool, Breast Cancer Now grant (2014MayPR292), NLD BBSRC doctoral training programme (BB/M011186/1/1797330), European Project: 741773,AAA, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG)
Subjects: Polarity & Cytoskeleton, macromolecular substances, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Biology, Microtubules, General Biochemistry, Genetics and Molecular Biology, Article, 03 medical and health sciences, Jurkat Cells, 0302 clinical medicine, Microtubule, Humans, Arp2/3 complex, Cytoskeleton, Molecular Biology, Mitosis, Interphase, Cells, Cultured, 030304 developmental biology, Microtubule nucleation, Actin nucleation, Anaphase, Centrosome, mitosis, WASH complex Subject Categories Cell Adhesion, 0303 health sciences, General Immunology and Microbiology, General Neuroscience, Cell Cycle, WASH complex, Articles, Actins, Cell biology, Actin Cytoskeleton, Mitotic exit, Protein Multimerization, Cell Adhesion, Polarity & Cytoskeleton, centrosomal actin, 030217 neurology & neurosurgery, HeLa Cells
Abstract: International audience; Cells going through mitosis undergo precisely timed changes in cell shape and organisation, which serve to ensure the fair partitioning of cellular components into the two daughter cells. These structural changes are driven by changes in actin filament and microtubule dynamics and organisation. While most evidence suggests that the two cytoskeletal systems are remodelled in parallel during mitosis, recent work in interphase cells has implicated the centrosome in both microtubule and actin nucleation, suggesting the potential for regulatory crosstalk between the two systems. Here, by using both in vitro and in vivo assays to study centrosomal actin nucleation as cells pass through mitosis, we show that mitotic exit is accompanied by a burst in cytoplasmic actin filament formation that depends on WASH and the Arp2/3 complex. This leads to the accumulation of actin around centrosomes as cells enter anaphase and to a corresponding reduction in the density of centrosomal microtubules. Taken together, these data suggest that the mitotic regulation of centrosomal WASH and the Arp2/3 complex controls local actin nucleation, which may function to tune the levels of centrosomal microtubules during passage through mitosis.
Published: 2019

7. Quantitative regulation of the dynamic steady state of actin networks

Author: Tobbias Klar, Christophe Guérin, Laurent Blanchoin, Téa Aleksandra Icheva, Manuel Théry, Angelika Manhart, Rajaa Boujemaa-Paterski, Alex Mogilner, New York University [New York] (NYU), NYU System (NYU), New york University, Department of Biology, NYU System (NYU)-NYU System (NYU), CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Army Research Office (W911NF-17-1-0417), ANR-14-CE11-0003-01,MaxForce, European Project: 741773,AAA, Physiologie cellulaire et végétale (LPCV), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), ANR-14-CE11-0003,MaxForce,Maximiser la production de force: de la molécule au tissu(2014), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG)
Subjects: Steady state (electronics), QH301-705.5, none, Science, Motility, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, macromolecular substances, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, 0302 clinical medicine, cell biology, Animals, Protein Interaction Maps, Biology (General), Actin, 030304 developmental biology, Physics, 0303 health sciences, General Immunology and Microbiology, General Neuroscience, actin disassembly, General Medicine, Models, Theoretical, Cofilin, Cell function, Actins, actin network length, Destrin, Treadmilling, Actin Depolymerizing Factors, Biophysics, Medicine, Rabbits, Protein Multimerization, ADF/Cofilin, actin, 030217 neurology & neurosurgery, Heterogeneous network, Research Article
Abstract: International audience; Principles of regulation of actin network dimensions are fundamentally important for cell functions, yet remain unclear. Using both in vitro and in silico approaches, we studied the effect of key parameters, such as actin density, ADF/Cofilin concentration and network width on the network length. In the presence of ADF/Cofilin, networks reached equilibrium and became treadmilling. At the trailing edge, the network disintegrated into large fragments. A mathematical model predicts the network length as a function of width, actin and ADF/Cofilin concentrations. Local depletion of ADF/Cofilin by binding to actin is significant, leading to wider networks growing longer. A single rate of breaking network nodes, proportional to ADF/Cofilin density and inversely proportional to the square of the actin density, can account for the disassembly dynamics. Selective disassembly of heterogeneous networks by ADF/Cofilin controls steering during motility. Our results establish general principles on how the dynamic steady state of actin network emerges from biochemical and structural feedbacks.
Published: 2019

8. Active cargo positioning in antiparallel transport networks

Author: Pascal Martin, Hajer Ennomani, Carles Blanch-Mercader, Laurent Blanchoin, Frank Jülicher, Jean-François Joanny, Wenxiang Cao, Enrique M. De La Cruz, Mathieu Richard, Physico-Chimie-Curie (PCC), Institut Curie-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Molecular Biophysics and Biochemistry, Yale University [New Haven], ESPCI ParisTech, Collège de France (CDF), Collège de France (CdF), Max Planck Institute for the Physics of Complex Systems (MPI-PKS), Max-Planck-Gesellschaft, Technische Universität Dresden (TUD), US NIH R01 Grant GM097348, ANR-10-IDEX-0001-02/11-LABX-0038,CelTisPhyBio,Des cellules aux tissus: au croisement de la Physique et de la Biologie(2010), European Project: 741773,AAA, Laboratoire Physico-Chimie Curie [Institut Curie] (PCC), Institut Curie [Paris]-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Physiologie cellulaire et végétale (LPCV), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL), Chaire Matière molle et biophysique, Collège de France (CdF (institution)), Technische Universität Dresden = Dresden University of Technology (TU Dresden), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Collège de France - Chaire Matière molle et biophysique
Subjects: intracellular transport, Materials science, actin cytoskeleton, Polarity (physics), myosin, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, macromolecular substances, Bead, Myosins, Antiparallel (biochemistry), 01 natural sciences, Protein filament, 03 medical and health sciences, Motion, 0103 physical sciences, Myosin, Molecular motor, Diffusion (business), 010306 general physics, Cytoskeleton, Actin, 030304 developmental biology, 0303 health sciences, Multidisciplinary, Biological Transport, Random walk, Actins, Single Molecule Imaging, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, PNAS Plus, visual_art, diffusion-drift process, visual_art.visual_art_medium, Biophysics, stochastic processes
Abstract: Cytoskeletal filaments assemble into dense parallel, antiparallel or disordered networks, providing a complex environment for active cargo transport and positioning by molecular motors. The interplay between the network architecture and intrinsic motor properties clearly affects transport properties but remains poorly understood. Here, by using surface micro-patterns of actin polymerization, we investigate stochastic transport properties of colloidal beads in antiparallel networks of overlapping actin filaments. We found that 200-nm beads coated with myosin-Va motors displayed directed movements towards positions where the net polarity of the actin network vanished, accumulating there. The bead distribution was dictated by the spatial profiles of local bead velocity and diffusion coefficient, indicating that a diffusion-drift process was at work. Remarkably, beads coated with heavy mero-myosin-II motors showed a similar behavior. However, although velocity gradients were steeper with myosin II, the much larger bead diffusion observed with this motor resulted in less precise positioning. Our observations are well described by a three-state model, in which active beads locally sense the net polarity of the network by frequently detaching from and reattaching to the filaments. A stochastic sequence of processive runs and diffusive searches results in a biased random walk. The precision of bead positioning is set by the gradient of net actin polarity in the network and by the run length of the cargo in an attached state. Our results unveiled physical rules for cargo transport and positioning in networks of mixed polarity.Significance statementCellular functions rely on small groups of molecular motors to transport their cargoes throughout the cell along polar filaments of the cytoskeleton. Cytoskeletal filaments self-assemble into dense networks comprising intersections and filaments of mixed polarity, challenging directed motor-based transport. Using micro-patterns of actin polymerization in-vitro, we investigated stochastic transport of colloidal beads in antiparallel networks of overlapping actin filaments. We found that beads coated with myosin motors sensed the net polarity of the actin network, resulting in active bead positioning to regions of neutral polarity with a precision depending on the motor type. A theoretical description of our experimental results provides the key physical rules for cargo transport and positioning in filament networks of mixed polarity.
Published: 2019
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9. Dynamic stability of the actin ecosystem

Author: Laurent Blanchoin, Julie Plastino, Laboratoire Physico-Chimie Curie [Institut Curie] (PCC), Institut Curie [Paris]-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CytoMorphoLab, Physiologie cellulaire et végétale (LPCV), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Fondation ARC pour la Recherche sur le Cancer (PJA 20151203487), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Physico-Chimie-Curie (PCC), Institut Curie-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and ANR-10-IDEX-0001-02/10-IDEX-0001,PSL,Paris Sciences et Lettres(2010)
Subjects: Steady state (electronics), Stability (learning theory), Network structure, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Biology, Microtubules, Steady state, 03 medical and health sciences, 0302 clinical medicine, Adenosine Triphosphate, ATP hydrolysis, Animals, Humans, Cytoskeleton, Actin, Ecosystem, 030304 developmental biology, 0303 health sciences, Cell Biology, Actins, Actin Cytoskeleton, Constant (mathematics), Biological system, 030217 neurology & neurosurgery
Abstract: In cells, actin filaments continuously assemble and disassemble while maintaining an apparently constant network structure. This suggests a perfect balance between dynamic processes. Such behavior, operating far out of equilibrium by the hydrolysis of ATP, is called a dynamic steady state. This dynamic steady state confers a high degree of plasticity to cytoskeleton networks that allows them to adapt and optimize their architecture in response to external changes on short time-scales, thus permitting cells to adjust to their environment. In this Review, we summarize what is known about the cellular actin steady state, and what gaps remain in our understanding of this fundamental dynamic process that balances the different forms of actin organization in a cell. We focus on the minimal steps to achieve a steady state, discuss the potential feedback mechanisms at play to balance this steady state and conclude with an outlook on what is needed to fully understand its molecular nature.
Published: 2019

10. Actin nucleation at the centrosome controls lymphocyte polarity

Author: Ana-Maria Lennon-Duménil, Pablo J. Sáez, Laurent Blanchoin, Odile Malbec, Manuel Théry, Maria-Isabel Yuseff, Mathieu Maurin, Alexis Gautreau, Damarys Loew, Jérémie Gaillard, Dorian Obino, Florent Dingli, Francesca Farina, Immunité et cancer (U932), Université Paris Descartes - Paris 5 (UPD5)-Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie [Paris], Laboratoire de Biochimie de l'Ecole polytechnique (BIOC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Departamento de Biologia Celular y Molecular, Pontificia Universidad Catolica de Chile, research grant from FONDECYT No. 1141182, ANR-12-BSV3-0014,PoLyBEX,Regulation de la réponse humorale par la polarité cellulaire et l'exocytose(2012), ANR-12-BSV5-0004,MITOTUBES,Disséquer la Dynamique des Microtubules en Mitose par Reconstitution de Sous-Modules du Fuseau(2012), European Project: 243103,EC:FP7:ERC,ERC-2009-StG,STRAPACEMI(2009), European Project: 310472,EC:FP7:ERC,ERC-2012-StG_20111109,SPICY(2012), Martin-Laffon, Jacqueline, BLANC - Regulation de la réponse humorale par la polarité cellulaire et l'exocytose - - PoLyBEX2012 - ANR-12-BSV3-0014 - BLANC - VALID, BLANC - Disséquer la Dynamique des Microtubules en Mitose par Reconstitution de Sous-Modules du Fuseau - - MITOTUBES2012 - ANR-12-BSV5-0004 - BLANC - VALID, Spatio-temporal regulation of antigen presentation and cell migration - STRAPACEMI - - EC:FP7:ERC2009-12-01 - 2015-11-30 - 243103 - VALID, Spatial Integration in Cell Cytoskeleton - SPICY - - EC:FP7:ERC2012-12-01 - 2017-11-30 - 310472 - VALID, Pontificia Universidad Católica de Chile (UC), Institut Curie-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institut Curie, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, cell division, Immunological Synapses, Proteome, Cell division, cell migration, LINC complex, Science, Down-Regulation, Receptors, Antigen, B-Cell, General Physics and Astronomy, Centrosome cycle, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, macromolecular substances, Biology, Lymphocyte Activation, Actin-Related Protein 2-3 Complex, Article, General Biochemistry, Genetics and Molecular Biology, Cell Line, Immunological synapse, Mice, 03 medical and health sciences, Cell polarity, Animals, Lymphocytes, [SDV.BC] Life Sciences [q-bio]/Cellular Biology, Actin, Actin nucleation, Cell Nucleus, Centrosome, Multidisciplinary, Centrosome associated protein, General Chemistry, actin associated protein, Actins, Cell biology, cell polarity, 030104 developmental biology, centrosome polarization, biological phenomena, cell phenomena, and immunity, Arp2/3, actin nucleation
Abstract: Cell polarity is required for the functional specialization of many cell types including lymphocytes. A hallmark of cell polarity is the reorientation of the centrosome that allows repositioning of organelles and vesicles in an asymmetric fashion. The mechanisms underlying centrosome polarization are not fully understood. Here we found that in resting lymphocytes, centrosome-associated Arp2/3 locally nucleates F-actin, which is needed for centrosome tethering to the nucleus via the LINC complex. Upon lymphocyte activation, Arp2/3 is partially depleted from the centrosome as a result of its recruitment to the immune synapse. This leads to a reduction in F-actin nucleation at the centrosome and thereby allows its detachment from the nucleus and polarization to the synapse. Therefore, F-actin nucleation at the centrosome—regulated by the availability of the Arp2/3 complex—determines its capacity to polarize in response to external stimuli., Cell polarity is marked by re-orientation of the centrosome, but the mechanisms governing centrosome polarization are poorly understood. Here Obino et al. show that in lymphocytes centrosome-associated Arp2/3 nucleates actin that tethers the centrosome to the nucleus; activation depletes Arp2/3 from the centrosome and frees it from the nucleus.
Published: 2016

11. Stem Cell-Like Properties of CK2β-down Regulated Mammary Cells

Author: Duchemin-Pelletier, Eve, Baulard, Megghane, Spreux, Elodie, Prioux, Magali, Burute, Mithila, Mograbi, Baharia, Guyon, Laurent, Thery, Manuel, Cochet, Claude, Filhol, Odile, Transduction du signal : signalisation calcium, phosphorylation et inflammation, Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Biologie du Cancer et de l'Infection (BCI ), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), CytoMorphoLab, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), EMI 00-092, Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire de Biologie à Grande Échelle (BGE - UMR S1038), Compartimentation et dynamique cellulaires (CDC), Centre National de la Recherche Scientifique (CNRS)-Institut Curie-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Physiologie cellulaire et végétale [2016-2019] (LPCV [2016-2019]), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale [2016-2019] (LPCV [2016-2019]), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Institut Curie [Paris]-Université Pierre et Marie Curie - Paris 6 (UPMC), INSERM, CEA, Ligue Nationale contre le Cancer, Ligue Comite de la Loire, University Grenoble Alpes, Espoir Foundation, ANR [PCV-08 CoCCINet], Immunité muqueuse et vaccination, Institut National de la Santé et de la Recherche Médicale (INSERM)-IFR50-Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Invasion mechanisms in angiogenesis and cancer (IMAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Ligue Comité de la Loire, ANR-08-PCVI-0027,CoCCINet,Construction of Cell-Cell Interaction Networks(2008), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-IFR50-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Côte d'Azur (UCA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Martin-Laffon, Jacqueline, Programme interdiciplinaire en physique et chimie du vivant - Construction of Cell-Cell Interaction Networks - - CoCCINet2008 - ANR-08-PCVI-0027 - PCV - VALID, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National de la Santé et de la Recherche Médicale (INSERM), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-IFR50-Université Côte d'Azur (UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)
Subjects: [SDV.EE.SANT]Life Sciences [q-bio]/Ecology, environment/Health, Epithelial to Mesenchymal Transition, EMT, [SDV.CAN]Life Sciences [q-bio]/Cancer, lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens, lcsh:RC254-282, Article, stem cell, breast cancer, [SDV.CAN] Life Sciences [q-bio]/Cancer, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], protein kinase CK2, [SDV.BBM.GTP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], ComputingMilieux_MISCELLANEOUS, epithelial plasticity
Abstract: International audience; The ubiquitous protein kinase CK2 has been demonstrated to be overexpressed in a number of human tumours. This enzyme is composed of two catalytic alpha or alpha' subunits and a dimer of beta regulatory subunits whose expression levels are probably implicated in CK2 regulation. Several recent papers reported that unbalanced expression of CK2 subunits is sufficient to drive epithelial to mesenchymal transition, a process involved in cancer invasion and metastasis. Herein, through transcriptomic and miRNA analysis together with comparison of cellular properties between wild type and CK2 beta-knock-down MCF10A cells, we show that down-regulation of CK2 beta subunit in mammary epithelial cells induces the acquisition of stem cell-like properties associated with perturbed polarity, CD44(high)/CD24(low) antigenic phenotype and the ability to grow under anchorage-independent conditions. These data demonstrate that a CK2 beta level establishes a critical cell fate threshold in the control of epithelial cell plasticity. Thus, this regulatory subunit functions as a nodal protein to maintain an epithelial phenotype and its depletion drives breast cell stemness.
Published: 2017

12. Coupling spindle position with mitotic exit in budding yeast: The multifaceted role of the small GTPase Tem1

Author: Simonetta Piatti, Ilaria Scarfone, Centre de recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de recherche en Biologie Cellulaire (CRBM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de recherches de biochimie macromoléculaire (CRBM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-IFR122-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Saccharomyces cerevisiae Proteins, Tem1, Aurora B kinase, Mitosis, mitotic exit network, Saccharomyces cerevisiae, Spindle Apparatus, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Polo-like kinase, Biology, Biochemistry, asymmetric cell division, Spindle pole body, spindle pole bodies, Monomeric GTP-Binding Proteins, Kinetochore, Cell Biology, Spindle apparatus, Cell biology, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Kar9, Mitotic exit, Multiprotein Complexes, Commentary, spindle positioning, Cytokinesis, Signal Transduction, spindle position checkpoint
Abstract: International audience; The budding yeast S. cerevisiae divides asymmetrically and is an excellent model system for asymmetric cell division. As for other asymmetrically dividing cells, proper spindle positioning along the mother-daughter polarity axis is crucial for balanced chromosome segregation. Thus, a surveillance mechanism named Spindle Position Checkpoint (SPOC) inhibits mitotic exit and cytokinesis until the mitotic spindle is properly oriented, thereby preventing the generation of cells with aberrant ploidies. The small GTPase Tem1 is required to trigger a Hippo-like protein kinase cascade, named Mitotic Exit Network (MEN), that is essential for mitotic exit and cytokinesis but also contributes to correct spindle alignment in metaphase. Importantly, Tem1 is the target of the SPOC, which relies on the activity of the GTPase-activating complex (GAP) Bub2-Bfa1 to keep Tem1 in the GDP-bound inactive form. Tem1 forms a hetero-trimeric complex with Bub2-Bfa1 at spindle poles (SPBs) that accumulates asymmetrically on the bud-directed spindle pole during mitosis when the spindle is properly positioned. In contrast, the complex remains symmetrically localized on both poles of misaligned spindles. We have recently shown that Tem1 residence at SPBs depends on its nucleotide state and, importantly, asymmetry of the Bub2-Bfa1-Tem1 complex does not promote mitotic exit but rather controls spindle positioning.
Published: 2015

13. Lipid polyunsaturation determines the extent of membrane structural changes induced by Amphotericin B in Pichia pastoris yeast

Author: Giovanna Fragneto, Valerie Laux, Michael Haertlein, Juliette Jouhet, Alexis de Ghellinck, Hanna Wacklin, Michele Sferrazza, Institut Laue-Langevin (ILL), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), European Spallation Source ESS AB, University of Copenhagen = Københavns Universitet (UCPH), European Project: 283883,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2011-1,NMI3-II(2012), ILL, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (KU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Membrane Fluidity, [SDV]Life Sciences [q-bio], Lipid Bilayers, Biophysics, Antifungal drug, Phospholipid, 02 engineering and technology, Biochemistry, Pichia, Pichia pastoris, 03 medical and health sciences, chemistry.chemical_compound, Amphotericin B, Ergosterol, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Antifungal activity, 030304 developmental biology, Yeast lipids, Neutron reflectometry, 0303 health sciences, biology, Cell Membrane, Polyunsaturation, Fungi, Membrane structure, Cell Biology, 021001 nanoscience & nanotechnology, biology.organism_classification, Lipids, Yeast, Sterol, Sterols, Membrane interaction, Membrane, chemistry, Membrane protein, Fatty Acids, Unsaturated, lipids (amino acids, peptides, and proteins), 0210 nano-technology
Abstract: Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.bbamem.2015.06.006.; International audience; The activity of the potent but highly toxic antifungal drug Amphotericin B (AmB), used intravenously to treat systemic fungal and parasitic infections, is widely accepted to result from its specific interaction with the fungal sterol ergosterol. While the effect of sterols on AmB activity has been intensely investigated, the role of membrane phospholipid composition has largely been ignored, and structural studies of native membranes have been hampered by their complex and disordered nature. We show for the first time that the structure of fungal membranes derived from Pichia pastoris yeast depends on the degree of lipid polyunsaturation, which has an impact on the structural consequences of AmB activity. AmB inserts in yeast membranes even in the absence of ergosterol, and forms an extra-membraneous layer whose thickness is resolved to be 4-5nm. In ergosterol-containing membranes, AmB insertion is accompanied by ergosterol extraction into this layer. The AmB-sponge mediated depletion of ergosterol from P. pastoris membranes gives rise to a significant membrane thinning effect that depends on the degree of lipid polyunsaturation. The resulting hydrophobic mismatch is likely to interfere with a much broader range of membrane protein functions than those directly involving ergosterol, and suggests that polyunsaturated lipids could boost the efficiency of AmB. Furthermore, a low degree of lipid polyunsaturation leads to least AmB insertion and may protect host cells against the toxic effects of AmB. These results provide a new framework based on lipid composition and membrane structure through which we can understand its antifungal action and develop better treatments.
Published: 2015

14. Physico-chemical and biological considerations for membrane wound evolution and repair in animal cells

Author: Ana Joaquina Jimenez, Franck Perez, CHU Grenoble, Hôpital Saint-Louis, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Compartimentation et dynamique cellulaires (CDC), Centre National de la Recherche Scientifique (CNRS)-Institut Curie [Paris]-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut Curie, Centre National de la Recherche Scientifique (CNRS), French Agence Nationale de la Recherche [ANR-12-BSV2-0003-01], Fondation Recherche Medicale [DEQ20120323723], LabEx CelTisPhyBio [ANR-10-LBX-0038, ANR-10-IDEX-0001-02], Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut Curie [Paris]-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Membrane shedding, [SDV]Life Sciences [q-bio], Cell, Membrane repair, Context (language use), Biology, Endocytosis, Exocytosis, Cell membrane, 03 medical and health sciences, 0302 clinical medicine, Line Tension, medicine, Animals, Humans, Lipid bilayer, 030304 developmental biology, Wound Healing, 0303 health sciences, Endosomal Sorting Complexes Required for Transport, Epidermis (botany), Cell Membrane, Cell Biology, Membrane tension, Cell biology, medicine.anatomical_structure, Wound healing, 030217 neurology & neurosurgery, Plasma membrane, Developmental Biology
Abstract: International audience; Membrane damage is a daily threat to the life of a cell, especially cells from muscles, gut, epidermis and vasculature, tissues that are particularly subjected to mechanical stress. Damages can come from different sources and give rise to different holes in terms of size and nature. For example, while some holes are simply scratches in the lipid bilayer, others are delimited by pore forming proteins. It is thus expectable that these wounds will not evolve similarly in a cellular context, and that repair mechanisms will differ to a certain extent. It would therefore be misleading to fully generalize cell membrane damage and repair, and consider it as one universal phenomenon. Indeed, damage has been observed in cells ranging from the rather small mammalian cells (similar to 30 mu m) to the very big Urchin egg (similar to 100 mu m). Moreover, the wounds observed or artificially induced in eukaryotic cells range from some nanometers to several micrometers, and can be delimited by particular molecules as mentioned before. This chapter aims at reviewing the different physico-chemical and biological parameters that can influence wound evolution in cells and to conciliate the different repair mechanisms that have been described by evaluating them in their cellular and wound type context.
Published: 2015

15. Dual Targeting of the Protein Methyltransferase PrmA Contributes to Both Chloroplastic and Mitochondrial Ribosomal Protein L11 Methylation in Arabidopsis

Author: Morgane Mininno, Jacqueline Martin-Laffon, Sabine Brugière, Claude Alban, Mélanie Leroux, Marianne Tardif, Sylvie Figuet, Meryl Mazzoleni, Stéphane Ravanel, Annabelle Gilgen, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie à Grande Échelle (BGE - UMR S1038), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-10-INBS-08-01/10-INBS-0008,ProFI,Infrastructure Française de Protéomique(2010), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), INRA (Department of Plant Biology ), ANR (Proteomics French Infrastructure) [ANR-10-INBS-08-01/10-INBS-0008], Université Grenoble Alpes, ANR-10-INBS-0008,ProFI,Infrastructure Française de Protéomique(2010), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)
Subjects: Ribosomal Proteins, Chloroplasts, Methyltransferase, Arabidopsis thaliana, Physiology, Molecular Sequence Data, Mutant, Arabidopsis, Germination, Plant Science, Dual targeting, Chloroplast, Methylation, Ribosome, Mitochondrial Proteins, Ribosomal protein, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Amino Acid Sequence, Photosynthesis, Mitochondrion, Binding site, Phylogeny, biology, Arabidopsis Proteins, Genetic Complementation Test, Methyltransferases, Plant, Cell Biology, General Medicine, biology.organism_classification, Molecular biology, Mitochondria, Protein Transport, Biochemistry, Protein Biosynthesis, Acetyltransferase, Mutation, Peptides, Ribosomes, Subcellular Fractions, Post-translational modifications
Abstract: Editor's Choice article: Free access to Full Text; International audience; Methylation of ribosomal proteins has long been described in prokaryotes and eukaryotes, but our knowledge about the enzymes responsible for these modifications in plants is scarce. The bacterial protein methyltransferase PrmA catalyzes the trimethylation of ribosomal protein L11 (RPL11) at three distinct sites. The role of these modifications is still unknown. Here, we show that PrmA from Arabidopsis thaliana (AtPrmA) is dually targeted to chloroplasts and mitochondria. Mass spectrometry and enzymatic assays indicated that the enzyme methylates RPL11 in plasto- and mitoribosomes in vivo. We determined that the Arabidopsis and Escherichia coli PrmA enzymes share similar product specificity, making trimethylated residues, but, despite an evolutionary relationship, display a difference in substrate site specificity. In contrast to the bacterial enzyme that trimethylates the ε-amino group of two lysine residues and the N-terminal α-amino group, AtPrmA methylates only one lysine in the MAFCK(D/E)(F/Y)NA motif of plastidial and mitochondrial RPL11. The plant enzyme possibly methylates the N-terminus of plastidial RPL11, whereas mitochondrial RPL11 is N-α-acetylated by an unknown acetyltransferase. Lastly, we found that an Arabidopsis prma-null mutant is viable in standard environmental conditions and no molecular defect could be associated with a lack of RPL11 methylation in leaf chloroplasts or mitochondria. However, the conservation of PrmA during the evolution of photosynthetic eukaryotes together with the location of methylated residues at the binding site of translation factors to ribosomes suggests that RPL11 methylation in plant organelles could be involved, in combination with other post-translational modifications, in optimizing ribosome function.
Published: 2015

16. Architecture Dependence of Actin Filament Network Disassembly

Author: Christophe Guérin, Laurent Blanchoin, Audrey Guillotin, Laurène Gressin, Alphée Michelot, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ANR-10- LABX-49-01,Labex GRAL,Labex GRAL, ANR-12-BSV5-0014,Contract,Nouveaux systèmes biomimétiques pour étudier la contractilité acto-myosine cellulaire(2012), ANR-14-CE11-0011-01,DiANe,ANR-14-CE11-0011-01, Irtelis PhD fellowship (CEA), Labex GRAL, ANR (ANR-12-BSV5-0014, ANR-14-CE11-0011-01), ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010), ANR-14-CE11-0011,Diane,Contractilité de réseaux d'actine induite par leur désassemblage(2014), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [SDV.BC]Life Sciences [q-bio]/Cellular Biology, macromolecular substances, Biology, environment and public health, General Biochemistry, Genetics and Molecular Biology, Protein filament, 03 medical and health sciences, 0302 clinical medicine, Yeasts, Filament severing, Animals, actin network, Cytoskeleton, Actin, 030304 developmental biology, 0303 health sciences, Aip1, Agricultural and Biological Sciences(all), Biochemistry, Genetics and Molecular Biology(all), Microfilament Proteins, Actin remodeling, Microfilament Protein, Cofilin, Actin cytoskeleton, Actins, Cell biology, Actin Cytoskeleton, Actin Depolymerizing Factors, Rabbits, MDia1, ADF/Cofilin, General Agricultural and Biological Sciences, 030217 neurology & neurosurgery
Abstract: International audience; Turnover of actin networks in cells requires the fast disassembly of aging actin structures. While ADF/cofilin and Aip1 have been identified as central players, how their activities are modulated by the architecture of the networks remains unknown. Using our ability to reconstitute a diverse array of cellular actin organizations, we found that ADF/cofilin binding and ADF/cofilin-mediated disassembly both depend on actin geometrical organization. ADF/cofilin decorates strongly and stabilizes actin cables, whereas its weaker interaction to Arp2/3 complex networks is correlated with their dismantling and their reorganization into stable architectures. Cooperation of ADF/cofilin with Aip1 is necessary to trigger the full disassembly of all actin filament networks. Additional experiments performed at the single-molecule level indicate that this cooperation is optimal above a threshold of 23 molecules of ADF/cofilin bound as clusters along an actin filament. Our results indicate that although ADF/cofilin is able to dismantle selectively branched networks through severing and debranching, stochastic disassembly of actin filaments by ADF/cofilin and Aip1 represents an efficient alternative pathway for the full disassembly of all actin networks. Our data support a model in which the binding of ADF/cofilin is required to trigger a structural change of the actin filaments, as a prerequisite for their disassembly by Aip1.
Published: 2015
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17. Polarity Reversal by Centrosome Repositioning Primes Cell Scattering during Epithelial-to-Mesenchymal Transition

Author: Joanne Young, Gaëlle Letort, Mithila Burute, Thomas Bessy, Sandrine Truchet, Odile Filhol, Qingzong Tseng, Guillaume Blin, Sally Lowell, Manuel Théry, Magali Prioux, Alloimmunité-Autoimmunité-Transplantation (A2T), Institut Universitaire d'Hématologie (IUH), Université Paris Diderot - Paris 7 (UPD7)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Génétique Animale et Biologie Intégrative (GABI), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, CytoMorphoLab, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), MRC Centre for Regenerative Medicine [Edinburgh, UK] (Institute for Stem Cell Research), University of Edinburgh-Institute for Stem Cell Research [Edinburgh, UK] (School of Biological Sciences), CYTOO SA [Grenoble, France], Invasion mechanisms in angiogenesis and cancer (IMAC), Biologie du Cancer et de l'Infection (BCI ), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), BPI France (ETICS, I1107018W), Ligue Nationale et Regionale contre le Cancer and Espoir Foundation, European Project: 310472,EC:FP7:ERC,ERC-2012-StG_20111109,SPICY(2012), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institute for Stem Cell Research [Edinburgh, UK] (School of Biological Sciences)-University of Edinburgh, Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), This work was supported by grants from the ERC (SpiCy, StG-310472) and the BPI France (ETICS, I1107018W). M.B. received a fellowship from the ANRT (CIFRE 2011/1730) and M.P. a fellowship from the Laboratory of Excellence (Grenoble Alliance for Integrated Structural Cell Biology). GB and SL are supported by fellowships from the Wellcome Trust. OFC is supported by La Ligue Nationale et Regionale contre le Cancer and Espoir Foundation., CIC - Biotherapie - Saint Louis ((CIC-BT 301)), Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Groupe Hospitalier Saint Louis - Lariboisière - Fernand Widal [Paris], Assistance publique - Hôpitaux de Paris (AP-HP) (APHP), CYTOO SA, Cytoo SA, Centre Development in Stem Cell Biology, University of Edinburgh-Institute for Stem Cell Research, Ligue Nationale et Regionale contre le Cancer and Espoir Foundation., Filhol, Odile, Spatial Integration in Cell Cytoskeleton - SPICY - - EC:FP7:ERC2012-12-01 - 2017-11-30 - 310472 - VALID, Physiologie cellulaire et végétale [2016-2019] (LPCV [2016-2019]), Institut National de la Santé et de la Recherche Médicale (INSERM)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Université Paris Diderot - Paris 7 (UPD7)-Groupe Hospitalier Saint Louis - Lariboisière - Fernand Widal [Paris], and Invasion mechanisms in angiogenesis and cancer [?-2019] (IMAC [?-2019])
Subjects: 0301 basic medicine, [SDV]Life Sciences [q-bio], Cell Cycle Proteins, migration, Cell junction, Mouse embryo, Microtubules, Mice, Cell polarity, polarity, Cytoskeleton, ComputingMilieux_MISCELLANEOUS, Cells, Cultured, Centrosome repositioning, biology, EMT, Cell Polarity, cytoskeleton, Epithelial to Mesenchymal Transition EMT, Cell biology, Biomechanical Phenomena, Mouse mammary gland, intercellular junctions, Mammalia, Female, Intracellular, microtubule, Epithelial-Mesenchymal Transition, stathmin, Microtubule network dynamics, Embryonic Development, Stathmin, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, General Biochemistry, Genetics and Molecular Biology, Article, 03 medical and health sciences, Mammary Glands, Animal, Microtubule, [SDV.EE.SANT] Life Sciences [q-bio]/Ecology, environment/Health, Animals, Humans, Epithelial–mesenchymal transition, Molecular Biology, Adaptor Proteins, Signal Transducing, [SDV.EE.SANT]Life Sciences [q-bio]/Ecology, environment/Health, Cell Biology, micropatterning, Polarity reversals, 030104 developmental biology, centrosome, Centrosome, biology.protein, Cell Adhesion Molecules, Developmental Biology, Micropatterned cells
Abstract: International audience; During epithelial-to-mesenchymal transition (EMT), cells lining the tissue periphery break up their cohesion to migrate within the tissue. This dramatic reorganization involves a poorly characterized reorientation of the apicobasal polarity of static epithelial cells into the front-rear polarity of migrating mesenchymal cells. To investigate the spatial coordination of intra-cellular reorganization with morphological changes, we monitored centrosome positioning during EMT in vivo, in developing mouse embryos and mammary gland, and in vitro, in cultured 3D cell aggregates and micropatterned cell doublets. In all conditions, centrosomes moved from their off-centered position next to intercellular junctions toward extracellular matrix adhesions on the opposite side of the nucleus, resulting in an effective internal polarity reversal. This move appeared to be supported by controlled micro- tubule network disassembly. Sequential release of cell confinement using dynamic micropatterns, and modulation of microtubule dynamics, confirmed that centrosome repositioning was responsible for further cell disengagement and scattering.
Published: 2017

18. Metabolic transformation of microalgae due to light acclimation and genetic modifications followed by laser ablation electrospray ionization mass spectrometry with ion mobility separation

Author: Akos Vertes, Bindesh Shrestha, Eric Maréchal, Denis Falconet, Sylwia A. Stopka, Department of Chemistry, The George Washington University (GW)-W. M. Keck Institute of Proteomics Technology and Applications, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy(Grant DE-FG02-01ER15129), ANR-12-BIME-0005,DiaDomOil,Domestication des diatomées pour la production de biocarburants(2012), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), George Washington University (GW)-W. M. Keck Institute of Proteomics Technology and Applications, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and ANR-12- BIME-0005,DiaDomOil,DiaDomOil
Subjects: Chlorophyll, Light, Metabolite, Laser ablation electrospray ionization, Chlamydomonas reinhardtii, 7. Clean energy, 01 natural sciences, Biochemistry, Analytical Chemistry, MGDG, light acclimation, genetic modifications, chemistry.chemical_compound, Microalgae, Metabolites, Electrochemistry, Spectroscopy, 0303 health sciences, education.field_of_study, biology, Chemistry, 3. Good health, Metabolome, Diacylglycerol, metabolic engineering, Aminoacids, DGDG, Chlorophyll b, Spectrometry, Mass, Electrospray Ionization, Population, Triacylglycerol, Metabolic engineering, 03 medical and health sciences, Biofuel, [CHIM]Chemical Sciences, Environmental Chemistry, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, education, 030304 developmental biology, 010401 analytical chemistry, lipid production, Glycerolipids, biology.organism_classification, 0104 chemical sciences, 13. Climate action, Phytoplankton
Abstract: International audience; Metabolic profiling of various microalga species and their genetic variants, grown under varied environmental conditions, has become critical to accelerate the exploration of phytoplankton biodiversity and biology. The accumulation of valuable metabolites, such as glycerolipids, is also sought in microalgae for biotechnological applications ranging from food, feed, medicine, cosmetics to bioenergy and green chemistry. In this report we describe the direct analysis of metabolites and lipids in small cell populations of the green alga Chlamydomonas reinhardtii, using laser ablation electrospray ionization (LAESI) mass spectrometry (MS) coupled with ion mobility separation (IMS). These microorganisms are capable of redirecting energy storage pathways from starch to neutral lipids depending on environmental conditions and nutrient availability. Metabolite and lipid productions were monitored in wild type (WT), and genetically modified C. reinhardtii strains with an impaired starch pathway. Lipids, such as triacylglycerols (TAG) and diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), were monitored over time under altered light conditions. More than 200 ions related to metabolites, e.g., arginine, cysteine, serine, palmitate, chlorophyll a, chlorophyll b, etc., were detected. The lipid profiles at different light intensities for strains with impaired starch pathway (Sta1 and Sta6) contained 26 glycerolipids, such as DGTS, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), as well as 33 TAG species. Results were obtained over a 72 hour time period under high and low light conditions for the WT species and the two mutants. Our results indicate that LAESI-IMS-MS can be utilized for the rapid analysis of increased TAG production at elevated light intensities. Compared to WT, the Sta6 strain showed 2.5 times higher lipid production at 72 hours under high light conditions. The results demonstrate our ability to rapidly observe numerous changes in metabolite and lipid levels in microalgal population. These capabilities are expected to facilitate the exploration of genetically altered microalgal strains for biofuel production.
Published: 2014

19. Cell Adhesion Geometry Regulates Non-Random DNA Segregation and Asymmetric Cell Fates in Mouse Skeletal Muscle Stem Cells

Author: Shahragim Tajbakhsh, Siham Yennek, Mithila Burute, Manuel Théry, Sorbonne Université (SU), Cellules Souches et Développement, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire d'Hématologie (IUH), Université Paris Diderot - Paris 7 (UPD7), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Cytoo SA, Association pour la Recherche sur le Cancer, ANR-10-LABX-0025,CEBA,CEnter of the study of Biodiversity in Amazonia(2010), ANR-06-BLAN-0039,Tajbakhsh,Genetic and cellular regulation of stem to differentiated states in mouse skeletal muscle(2006), European Project: 332893,332893, Sorbonne Universités, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ANR-10- LABX-25-01,CEBA,Labex CEBA ANR-10- LABX-25-01, and Tajbakhsh, Shahragim
Subjects: cell division, MESH: Cell Differentiation, Cell division, Mouse, MESH: Mice, Transgenic, Cell, asymetric micropatterns, MESH: Chromosome Segregation, Mitosis, Mice, Transgenic, MESH: Stem Cells, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Biology, Cell fate determination, DNA segregation, General Biochemistry, Genetics and Molecular Biology, Spindle pole body, MESH: Cell Adhesion, 03 medical and health sciences, chemistry.chemical_compound, Mice, 0302 clinical medicine, stem cells, Chromosome Segregation, medicine, Cell Adhesion, Animals, MESH: Animals, Cell adhesion, Muscle, Skeletal, lcsh:QH301-705.5, MESH: Mice, 030304 developmental biology, 0303 health sciences, MESH: Muscle, Skeletal, Cell growth, MESH: DNA, Cell Differentiation, DNA, Cell biology, medicine.anatomical_structure, chemistry, lcsh:Biology (General), Mammalia, Muscle, MESH: Cell Division, 030217 neurology & neurosurgery
Abstract: International audience; Cells of several metazoan species have been shown to non-randomly segregate their DNA such that older template DNA strands segregate to one daughter cell. The mechanisms that regulate this asymmetry remain undefined. Determinants of cell fate are polarized during mitosis and partitioned asymmetrically as the spindle pole orients during cell division. Chromatids align along the pole axis; therefore, it is unclear whether extrinsic cues that determine spindle pole position also promote non-random DNA segregation. To mimic the asymmetric divisions seen in the mouse skeletal stem cell niche, we used micropatterns coated with extracellular matrix in asymmetric and symmetric motifs. We show that the frequency of non-random DNA segregation and transcription factor asymmetry correlates with the shape of the motif and that these events can be uncoupled. Furthermore, regulation of DNA segregation by cell adhesion occurs within a defined time interval. Thus, cell adhesion cues have a major impact on determining both DNA segregation patterns and cell fates.
Published: 2014
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20. Glycerolipids in photosynthesis: Composition, synthesis and trafficking

Author: Denis Falconet, Maryse A. Block, Laurence Boudière, Giovanni Finazzi, Dimitris Petroutsos, Sylvaine Roy, Olivier Bastien, Fabrice Rébeillé, Eric Maréchal, Norbert Rolland, Morgane Michaud, Juliette Jouhet, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Région Rhône-Alpes and Labex GRAL (Grenoble Alliance for Integrated Structural Cell Biology), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Cyanobacteria, Galactolipid, [SDV]Life Sciences [q-bio], Biophysics, plant, Review, Monogalactosyldiacylglycerol, Photosynthesis, Thylakoids, Biochemistry, lipids, chemistry.chemical_compound, Membrane Lipids, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Digalactosyldiacylglycerol, Phosphatidylglycerol, biology, Protein Stability, food and beverages, Biological Transport, Cell Biology, biology.organism_classification, chloroplast membranes, Biosynthetic Pathways, Chloroplast, Metabolic pathway, Membrane, Eukaryotic Cells, chemistry, Prokaryotic Cells, Thylakoid, Sulfoquinovosyldiacylglycerol, Glycolipids, Sulfolipid
Abstract: International audience; : Glycerolipids constituting the matrix of photosynthetic membranes, from cyanobacteria to chloroplasts of eukaryotic cells, comprise monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sulfoquinovosyldiacylglycerol and phosphatidylglycerol. This review covers our current knowledge on the structural and functional features of these lipids in various cellular models, from prokaryotes to eukaryotes. Their relative proportions in thylakoid membranes result from highly regulated and compartmentalized metabolic pathways, with a cooperation, in the case of eukaryotes, of non-plastidic compartments. This review also focuses on the role of each of these thylakoid glycerolipids in stabilizing protein complexes of the photosynthetic machinery, which might be one of the reasons for their fascinating conservation in the course of evolution. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
Published: 2014
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21. Actin Dynamics, Architecture, and Mechanics in Cell Motility

Author: Laurent Blanchoin, Rajaa Boujemaa-Paterski, Cécile Sykes, Julie Plastino, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut de Biosciences et de Biotechnologies de Grenoble (ex-IRTSV) (BIG), Institut National de la Santé et de la Recherche Médicale (INSERM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Physico-Chimie-Curie (PCC), Centre National de la Recherche Scientifique (CNRS)-Institut Curie [Paris]-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC), Agence Nationale de la Recherche [ANR-08-BLAN-0012-12, ANR-09-BLAN-283, ANR-12-BSV5-0014], Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut Curie [Paris]-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Institut Curie-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Physiology, review, Arp2/3 complex, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, macromolecular substances, mechanical properties, cell motility, Biology, Microfilament, Tight Junctions, actin dynamics, 03 medical and health sciences, 0302 clinical medicine, Cell Movement, Physiology (medical), Myosin, Morphogenesis, Animals, Humans, Cytoskeleton, Molecular Biology, 030304 developmental biology, 0303 health sciences, Actin remodeling, cytoskeleton, General Medicine, Actin cytoskeleton, Actins, Cell biology, Actin Cytoskeleton, biology.protein, Lamellipodium, Filopodia, 030217 neurology & neurosurgery
Abstract: International audience; Tight coupling between biochemical and mechanical properties of the actin cytoskeleton drives a large range of cellular processes including polarity establishment, morphogenesis, and motility. This is possible because actin filaments are semi-flexible polymers that, in conjunction with the molecular motor myosin, can act as biological active springs or "dashpots" (in laymen's terms, shock absorbers or fluidizers) able to exert or resist against force in a cellular environment. To modulate their mechanical properties, actin filaments can organize into a variety of architectures generating a diversity of cellular organizations including branched or crosslinked networks in the lamellipodium, parallel bundles in filopodia, and antiparallel structures in contractile fibers. In this review we describe the feedback loop between biochemical and mechanical properties of actin organization at the molecular level in vitro, then we integrate this knowledge into our current understanding of cellular actin organization and its physiological roles.
Published: 2014

22. Inhibitory signalling to the Arp2/3 complex steers cell migration

Author: Roman Gorelik, Laurent Blanchoin, Ivan Bièche, Susan Fetics, Goran Lakisic, Fabienne Pierre, Violaine David, Anne-Gaëlle Planson, Klemens Rottner, Valérie Campanacci, Adeline Boyreau, Jacqueline Cherfils, Anika Steffen, Isaline Herrada, Julien G. Dumortier, Nicolas B. David, Antonina Y. Alexandrova, J. Victor Small, Tamara A. Chipysheva, Sophie Vacher, Ksenia Oguievetskaia, Joern Linkner, Christophe Guérin, Irene Dang, Florence A. Giger, Emmanuel Derivery, Maria Nemethova, Carla Sousa-Blin, Jan Faix, Nadine Peyriéras, V. D. Ermilova, Alexis Gautreau, Sophie Zinn-Justin, Véronique Henriot, Laboratoire d'Enzymologie et Biochimie Structurales (LEBS), Centre National de la Recherche Scientifique (CNRS), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institute for Biophysical Chemistry, Hannover Medical School [Hannover] (MHH), Institute of Molecular Biotechnology, Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institute of Carcinogenesis, Russian Academy of Medical Sciences, Oncogenetic Laboratory, Institut Curie [Paris], Système membranaires, photobiologie, stress et détoxication (SMPSD), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institute of Genetics, Rheinische Friedrich-Wilhelms-Universität Bonn, Neurobiologie et Développement (N&eD), Institut des Systèmes Complexes - Paris Ile-de-France (ISC-PIF), École normale supérieure - Cachan (ENS Cachan)-Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-École polytechnique (X)-Institut Curie [Paris]-Centre National de la Recherche Scientifique (CNRS), Institut de Neurobiologie Alfred Fessard (INAF), Helmholtz Centre for Infection Research (HZI), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut Curie, Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Cachan (ENS Cachan)-Université Panthéon-Sorbonne (UP1)-Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-École polytechnique (X)-Institut Curie-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris
Subjects: MESH: Signal Transduction, Embryo, Nonmammalian, Arp2/3 complex, MESH: Dictyostelium, Dictyostelium discoideum, Gene Knockout Techniques, Mice, 0302 clinical medicine, Cell Movement, MESH: Animals, MESH: Proteins, Pseudopodia, MESH: Cell Movement, Zebrafish, MESH: Gene Knockout Techniques, dynamic, 0303 health sciences, Multidisciplinary, actin polymerization, biology, Actin-Related Protein 2-3 Complex, Cell migration, leading edge, Cell biology, motility, MESH: HEK293 Cells, [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], Lamellipodium, Signal Transduction, Cell signaling, macromolecular substances, Cell Line, 03 medical and health sciences, Animals, Humans, endocytosis, dictyostelium, MESH: Zebrafish, MESH: Mice, Actin, 030304 developmental biology, MESH: Humans, MESH: Proto-Oncogene Proteins c-akt, Proteins, MESH: Embryo, Nonmammalian, biology.organism_classification, MESH: Cell Line, MESH: Actin-Related Protein 2-3 Complex, HEK293 Cells, filament, MESH: Pseudopodia, network, lamellipodia, biology.protein, Carrier Proteins, Proto-Oncogene Proteins c-akt, wasp scar protein, 030217 neurology & neurosurgery
Abstract: International audience; Cell migration requires the generation of branched actin networks that power the protrusion of the plasma membrane in lamellipodia. The actin-related proteins 2 and 3 (Arp2/3) complex is the molecular machine that nucleates these branched actin networks. This machine is activated at the leading edge of migrating cells by Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein (WAVE, also known as SCAR). The WAVE complex is itself directly activated by the small GTPase Rac, which induces lamellipodia. However, how cells regulate the directionality of migration is poorly understood. Here we identify a new protein, Arpin, that inhibits the Arp2/3 complex in vitro, and show that Rac signalling recruits and activates Arpin at the lamellipodial tip, like WAVE. Consistently, after depletion of the inhibitory Arpin, lamellipodia protrude faster and cells migrate faster. A major role of this inhibitory circuit, however, is to control directional persistence of migration. Indeed, Arpin depletion in both mammalian cells and Dictyostelium discoideum amoeba resulted in straighter trajectories, whereas Arpin microinjection in fish keratocytes, one of the most persistent systems of cell migration, induced these cells to turn. The coexistence of the Rac-Arpin-Arp2/3 inhibitory circuit with the Rac-WAVE-Arp2/3 activatory circuit can account for this conserved role of Arpin in steering cell migration.
Published: 2013

23. A variant of LEAFY reveals its capacity to stimulate meristem development by inducingRAX1

Author: Vojislava Grbic, Sophie Périgon, Marie Monniaux, Nela Mihajlovic, Gilles Vachon, François Parcy, Gabrielle Tichtinsky, Edwige Moyroud, Robin Michard, Marie Le Masson, Emmanuel Thévenon, Anna Kalinina, Camille Sayou, Hicham Chahtane, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Department of Biology, University of Western Ontario, University of Western Ontario (UWO), Charmful ANR (Agence Nationale de la Recherche) program, Natural Sciences and Engineering Research Council of Canada, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0106 biological sciences, Mutant, Arabidopsis, plant, Plant Science, 01 natural sciences, LFY, Gene Expression Regulation, Plant, Arabidopsis thaliana, transcription factor, chemistry.chemical_classification, 0303 health sciences, Crystallography, Gene Expression Regulation, Developmental, food and beverages, RAX1, Plants, Genetically Modified, flower, Cell biology, DNA-Binding Proteins, Inflorescence, Meristem, Flowers, Biology, Models, Biological, 03 medical and health sciences, Auxin, Two-Hybrid System Techniques, Axillary bud, Botany, meristem development, Genetics, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Nucleotide Motifs, Leafy, Transcription factor, Alleles, 030304 developmental biology, angiospermeae, Arabidopsis Proteins, fungi, Cell Biology, biology.organism_classification, Protein Structure, Tertiary, LEAFY, Plant Leaves, chemistry, Seedlings, Mutation, gene expression, Protein Multimerization, auxin, Transcription Factors, 010606 plant biology & botany
Abstract: International audience; In indeterminate inflorescences, floral meristems develop on the flanks of the shoot apical meristem, at positions determined by auxin maxima. The floral identity of these meristems is conferred by a handful of genes called floral meristem identity genes, among which the LEAFY (LFY) transcription factor plays a prominent role. However, the molecular mechanism controlling the early emergence of floral meristems remains unknown. A body of evidence indicates that LFY may contribute to this developmental shift, but a direct effect of LFY on meristem emergence has not been demonstrated. We have generated a LFY allele with reduced floral function and revealed its ability to stimulate axillary meristem growth. This role is barely detectable in the lfy single mutant but becomes obvious in several double mutant backgrounds and plants ectopically expressing LFY. We show that this role requires the ability of LFY to bind DNA, and is mediated by direct induction of REGULATOR OF AXILLARY MERISTEMS1 (RAX1) by LFY. We propose that this function unifies the diverse roles described for LFY in multiple angiosperm species, ranging from monocot inflorescence identity to legume leaf development, and that it probably pre-dates the origin of angiosperms.
Published: 2013

24. Rubisco small-subunit α-helices control pyrenoid formation in Chlamydomonas

Author: Howard Griffiths, Todor Genkov, Moritz T. Meyer, Juliette Jouhet, Robert J. Spreitzer, Jeremy N. Skepper, Madeline C. Mitchell, Department of Plant Sciences, University of Cambridge [UK] (CAM), Department of Biochemistry [Lincoln], University of Nebraska [Lincoln], University of Nebraska System-University of Nebraska System, Department of Physiology, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de Biosciences et de Biotechnologies de Grenoble (ex-IRTSV) (BIG), Institut National de la Santé et de la Recherche Médicale (INSERM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA), Biotechnology and Biological Sciences Research Council Grant BB/I024518/1 ('Combining Algal and Plant Photosynthesis') and Department of Energy Grant DE-FG02-00ER15044, Department of Biochemistry, University of Nebraska–Lincoln, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Institut National de la Santé et de la Recherche Médicale (INSERM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: 0106 biological sciences, Oxygenase, Algae, Ribulose-Bisphosphate Carboxylase, Molecular Sequence Data, carbon fixation, Chlamydomonas reinhardtii, ribulose -1, Photosynthesis, 01 natural sciences, Protein Structure, Secondary, Pyrenoid, Structure-Activity Relationship, 03 medical and health sciences, chloroplast, Spinacia oleracea, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Amino Acid Sequence, 030304 developmental biology, Organelles, Autotrophic Processes, 0303 health sciences, photosynthesis, Multidisciplinary, biology, 5- bisphosphate carboxylase, Chlamydomonas, RuBisCO, Biological Sciences, Carbon Dioxide, biology.organism_classification, Carbon, Pyruvate carboxylase, Oxygen, Kinetics, Phenotype, pyrenoid, Biochemistry, biology.protein, CO2 concentrating mechanism, Gene Deletion, 010606 plant biology & botany
Abstract: The pyrenoid is a subcellular microcompartment in which algae sequester the primary carboxylase, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The pyrenoid is associated with a CO 2 -concentrating mechanism (CCM), which improves the operating efficiency of carbon assimilation and overcomes diffusive limitations in aquatic photosynthesis. Using the model alga Chlamydomonas reinhardtii , we show that pyrenoid formation, Rubisco aggregation, and CCM activity relate to discrete regions of the Rubisco small subunit (SSU). Specifically, pyrenoid occurrence was shown to be conditioned by the amino acid composition of two surface-exposed α-helices of the SSU: higher plant-like helices knock out the pyrenoid, whereas native algal helices establish a pyrenoid. We have also established that pyrenoid integrity was essential for the operation of an active CCM. With the algal CCM being functionally analogous to the terrestrial C 4 pathway in higher plants, such insights may offer a route toward transforming algal and higher plant productivity for the future.
Published: 2012

25. Comparative Transcriptomic Analysis of Salt Adaptation in Roots of Contrasting Medicago truncatula Genotypes

Author: Véronique Gruber, Jean-Laurent Ichanté, Axel de Zélicourt, Laura de Lorenzo, Benoit Alunni, Sandrine Imbeaud, Hervé Delacroix, Sandrine Blanchet, Carole Laffont, Mounawer Badri, Anouck Diet, Julie Plet, Esther M. González, Florian Frugier, Ons Zahaf, Martin Crespi, Ana Zabalza, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences du végétal (ISV), Centre National de la Recherche Scientifique (CNRS), Génomique Fonctionnelle des Tumeurs Solides (U1162), Université Paris 13 (UP13)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre de génétique moléculaire (CGM), Université Paris-Sud - Paris 11 (UP11), Laboratoire de physiologie cellulaire végétale ( LPCV ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut National de la Recherche Agronomique ( INRA ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des sciences du végétal ( ISV ), Centre National de la Recherche Scientifique ( CNRS ), Genomique Fonctionnelle des Tumeurs Solides, Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Université Paris Descartes - Paris 5 ( UPD5 ) -IFR105-Université Paris Diderot - Paris 7 ( UPD7 ), Centre de génétique moléculaire ( CGM ), and Université Paris-Sud - Paris 11 ( UP11 )
Subjects: 0106 biological sciences, [ SDV.BV ] Life Sciences [q-bio]/Vegetal Biology, MESH : Molecular Sequence Data, MESH : Plant Roots, MESH: Plant Roots, MESH : Genotype, Plant Science, Sodium Chloride, 01 natural sciences, Plant Roots, Transcriptome, MESH: Genotype, Gene Expression Regulation, Plant, MESH: Medicago truncatula, MESH : Adaptation, Physiological, Plant Proteins, 2. Zero hunger, Abiotic component, chemistry.chemical_classification, 0303 health sciences, MESH: Plant Proteins, food and beverages, Adaptation, Physiological, Medicago truncatula, MESH : Sodium Chloride, Soil salinity, MESH: Sodium Chloride, Genotype, Molecular Sequence Data, Biology, 03 medical and health sciences, MESH: Gene Expression Profiling, Auxin, MESH : Plant Proteins, Botany, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, MESH: Gene Expression Regulation, Plant, Gene, Molecular Biology, 030304 developmental biology, MESH: Molecular Sequence Data, Abiotic stress, MESH : Gene Expression Profiling, MESH : Medicago truncatula, Gene Expression Profiling, fungi, 15. Life on land, biology.organism_classification, MESH: Adaptation, Physiological, chemistry, Adaptation, MESH : Gene Expression Regulation, Plant, 010606 plant biology & botany
Abstract: International audience; Evolutionary diversity can be driven by the interaction of plants with different environments. Molecular bases involved in ecological adaptations to abiotic constraints can be explored using genomic tools. Legumes are major crops worldwide and soil salinity is a main stress affecting yield in these plants. We analyzed in the Medicago truncatula legume the root transcriptome of two genotypes having contrasting responses to salt stress: TN1.11, sampled in a salty Tunisian soil, and the reference Jemalong A17 genotype. TN1.11 plants show increased root growth under salt stress as well as a differential accumulation of sodium ions when compared to A17. Transcriptomic analysis revealed specific gene clusters preferentially regulated by salt in root apices of TN1.11, notably those related to the auxin pathway and to changes in histone variant isoforms. Many genes encoding transcription factors (TFs) were also differentially regulated between the two genotypes in response to salt. Among those selected for functional studies, overexpression in roots of the A17 genotype of the bHLH-type TF most differentially regulated between genotypes improved significantly root growth under salt stress. Despite the global complexity of the differential transcriptional responses, we propose that an increase in this bHLH TF expression may be linked to the adaptation of M. truncatula to saline soil environments.
Published: 2012
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26. Biochemical and Structural Characterization of the Arabidopsis Bifunctional Enzyme Dethiobiotin Synthetase–Diaminopelargonic Acid Aminotransferase: Evidence for Substrate Channeling in Biotin Synthesis

Author: Virginie Pautre, David Cobessi, Claude Alban, Jean-Luc Ferrer, Renaud Dumas, Céline Meinguet, Institut de biologie structurale (IBS - UMR 5075), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie structurale (IBS - UMR 5075 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG)
Subjects: Models, Molecular, 0106 biological sciences, Arabidopsis thaliana, DAPA, Arabidopsis, plant, Plant Science, vitamin B8, Ligands, 01 natural sciences, Protein Structure, Secondary, Substrate Specificity, chemistry.chemical_compound, Biotin, Catalytic Domain, Carbon-Nitrogen Ligases, Amino Acids, Research Articles, chemistry.chemical_classification, 0303 health sciences, biology, Recombinant Proteins, bifunctional enzyme, Biochemistry, Protein Binding, Subcellular Fractions, crystal structure, Molecular Sequence Data, Substrate channeling, physicochemical properties, Chimeric gene, 03 medical and health sciences, DTBS, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Phosphofructokinase 2, Amino Acid Sequence, Transaminases, 030304 developmental biology, Arabidopsis Proteins, substrate channeling, Active site, metabolic pathway, Cell Biology, biology.organism_classification, Fusion protein, Biosynthetic Pathways, Protein Structure, Tertiary, Enzyme, chemistry, kinetics, Mutation, Biocatalysis, biotin synthesis, biology.protein, Protein Multimerization, Holoenzymes, 010606 plant biology & botany
Abstract: International audience; Diaminopelargonic acid aminotransferase (DAPA-AT) and dethiobiotin synthetase (DTBS) catalyze the antepenultimate and the penultimate steps, respectively, of biotin synthesis. Whereas DAPA-AT and DTBS are encoded by distinct genes in bacteria, in biotin-synthesizing eukaryotes (plants and most fungi), both activities are carried out by a single enzyme encoded by a bifunctional gene originating from the fusion of prokaryotic monofunctional ancestor genes. In few angiosperms, including Arabidopsis thaliana, this chimeric gene (named BIO3-BIO1) also produces a bicistronic transcript potentially encoding separate monofunctional proteins that can be produced following an alternative splicing mechanism. The functional significance of the occurrence of a bifunctional enzyme in biotin synthesis pathway in eukaryotes and the relative implication of each of the potential enzyme forms (bifunctional versus monofunctional) in the plant biotin pathway are unknown. In this study, we demonstrate that the BIO3-BIO1 fusion protein is the sole protein form produced by the BIO3-BIO1 locus in Arabidopsis. The enzyme catalyzes both DAPA-AT and DTBS reactions in vitro and is targeted to mitochondria in vivo. Our biochemical and kinetic characterizations of the pure recombinant enzyme show that in the course of the reaction, the DAPA intermediate is directly transferred from the DAPA-AT active site to the DTBS active site. Analysis of several structures of the enzyme crystallized in complex with and without its ligands reveals key structural elements involved for acquisition of bifunctionality and brings, together with mutagenesis experiments, additional evidences for substrate channeling.
Published: 2012

27. A stochastic process approach of the drake equation parameters

Author: Olivier Bastien, Pascal Ballet, Nicolas Glade, AGeing and IMagery (AGIM), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Informatique des Systèmes Complexes (LISYC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), French Agence Nationale de la Recherche, Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: 010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), Poisson processes, astrobiology, Structure (category theory), FOS: Physical sciences, 01 natural sciences, Measure (mathematics), Physics::Popular Physics, [MATH.MATH-GM]Mathematics [math]/General Mathematics [math.GM], Simple (abstract algebra), 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Applied mathematics, Algebraic expression, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, Search for extraterrestrial intelligence, 0105 earth and related environmental sciences, Mathematics, Measured quantity, Earth and Planetary Astrophysics (astro-ph.EP), Drake equation, Stochastic process, SETI, drake formula, Space and Planetary Science, Astrophysics - Earth and Planetary Astrophysics
Abstract: The number N of detectable (i.e. communicating) extraterrestrial civilizations in the Milky Way galaxy is usually done by using the Drake equation. This equation was established in 1961 by Frank Drake and was the first step to quantifying the SETI field. Practically, this equation is rather a simple algebraic expression and its simplistic nature leaves it open to frequent re-expression An additional problem of the Drake equation is the time-independence of its terms, which for example excludes the effects of the physico-chemical history of the galaxy. Recently, it has been demonstrated that the main shortcoming of the Drake equation is its lack of temporal structure, i.e., it fails to take into account various evolutionary processes. In particular, the Drake equation doesn't provides any error estimation about the measured quantity. Here, we propose a first treatment of these evolutionary aspects by constructing a simple stochastic process which will be able to provide both a temporal structure to the Drake equation (i.e. introduce time in the Drake formula in order to obtain something like N(t)) and a first standard error measure., 22 pages, 0 figures, 1 table, accepted for publication in the International Journal of Astrobiology
Published: 2012

28. Arabidopsis capping protein senses cellular phosphatidic acid levels and transduces these into changes in actin cytoskeleton dynamics

Author: Roman Pleskot, Martin Potocký, Jessica L. Henty-Ridilla, Laurent Blanchoin, Christopher J. Staiger, Jiejie Li, Department of Biological Sciences [Lafayette IN], Purdue University [West Lafayette], Institute of Experimental Botany of the Czech Academy of Sciences (IEB / CAS), Czech Academy of Sciences [Prague] (CAS), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Biological Sciences and Bindley Bioscience Center, Institute of Experimental Botany, Czech Academy of Sciences [Prague] (ASCR), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Arabidopsis thaliana, capping protein, Actin Capping Proteins, Arabidopsis, Arp2/3 complex, Phosphatidic Acids, plant, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Plant Science, macromolecular substances, actin-binding protein, 01 natural sciences, actin dynamics, 03 medical and health sciences, Actin-binding protein, Cytoskeleton, phospholipids, 030304 developmental biology, 0303 health sciences, biology, Arabidopsis Proteins, Actin remodeling, cytoskeleton, actin binding protein, biology.organism_classification, Actin cytoskeleton, Cell biology, Addendum, Actin Cytoskeleton, Profilin, biology.protein, MDia1, actin, signal transduction, 010606 plant biology & botany
Abstract: Addendum to: J Li, JL Henty-Ridilla, S Huang, X Wang, L Blanchoin, CJ Staiger. Capping protein modulates the dynamic behavior of actin filaments in response to phosphatidic acid in Arabidopsis.. Plant Cell 2012; 24:; International audience; Plants respond rapidly and precisely to a broad spectrum of developmental, biotic and abiotic cues. In many instances, signaling cascades involved in transducing this information result in changes to the cellular architecture and cytoskeletal rearrangements. Based originally on paradigms for animal cell signaling, phospholipids have received increased scrutiny as key intermediates for transmitting information to the actin cytoskeleton. Significantly, a wealth of biochemical data for plant actin-binding proteins (ABPs) demonstrates that many of these interact with phosphoinositide lipids in vitro. Moreover, phosphatidic acid (PA) has been identified not only as an abundant structural lipid in plants, but also as an intermediary in developmental and stress signaling pathways that lead to altered actin organization. Several years ago, the heterodimeric capping protein (CP) from Arabidopsis was demonstrated to bind PA and is negatively regulated by this lipid in vitro. Whether this form of regulation occurs in cells, however, remained a mystery. A new study, that combines live-cell imaging of cytoskeletal dynamics with reverse-genetic analyses in Arabidopsis, provides compelling new evidence that CP is inhibited from binding filament ends in the presence of PA in vivo. This allows rapid actin polymerization and increases in filament abundance following stimulation and could be one key factor in the physiological responses of plant cells to environmental stimuli.
Published: 2012

29. Differential CO2 effect on primary carbon metabolism of flag leaves in durum wheat (Triticum durum Desf.)

Author: Aranjuelo, Iker, Erice, Gorka, Sanz-Sáez, Alvaro, Abadie, Cyril, Gilard, Françoise, Gil-Quintana, Erena, Avice, Jean-Christophe, Staudinger, Christiana, Wienkoop, Stefanie, Araus, Jose L, Bourguignon, Jacques, Irigoyen, Juan J, Tcherkez, Guillaume, Department of Plant Biology and Ecology (Bilbao, Spain), Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Institut de Biologie des Plantes (IBP), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Universidad Pública de Navarra [Espagne] (UPNA), Ecophysiologie Végétale, Agronomie et Nutritions (EVA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Recherche Agronomique (INRA), University of Vienna [Vienna], Universitat de Barcelona (UB), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Universidad de Navarra [Pamplona] (UNAV), Australian National University (ANU), Spanish National Research and Development Programme (AGL2011-30386-C02-2 and AGL2013-44147-R, Ramón y Cajal program)- European Molecular Biology Organization (EMBO), Institut National de la Recherche Agronomique (INRA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Universidad Pública de Navarra [Espagne] = Public University of Navarra (UPNA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: cereal, carbon primary metabolism, Nitrogen, 5-bisphosphate carboxylase, Acclimatization, Ribulose-Bisphosphate Carboxylase, ribulose-1, plant, acclimation, Electron Transport, carboxylation, proteomics, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, leaf metabolism, Triticum, photosynthesis, biomass, Lysine, grain yield, food and beverages, nitrogen assimilation, Carbon Dioxide, metabolomics, Carbon, Plant Leaves, climate change, Triticum durum, rubisco, Edible Grain, carbon dioxide elevation
Abstract: International audience; C sink/source balance and N assimilation have been identified as target processes conditioning crop responsiveness to elevated CO2 . However, little is known about phenology-driven modifications of C and N primary metabolism at elevated CO2 in cereals such as wheat. Here, we examined the differential effect of elevated CO2 at two development stages (onset of flowering, onset of grain filling) in durum wheat (Triticum durum, var. Sula) using physiological measurements (photosynthesis, isotopes), metabolomics, proteomics and (15) N labelling. Our results show that growth at elevated CO2 was accompanied by photosynthetic acclimation through a lower internal (mesophyll) conductance but no significant effect on Rubisco content, maximal carboxylation or electron transfer. Growth at elevated CO2 altered photosynthate export and tended to accelerate leaf N remobilization, which was visible for several proteins and amino acids, as well as lysine degradation metabolism. However, grain biomass produced at elevated CO2 was larger and less N rich, suggesting that nitrogen use efficiency rather than photosynthesis is an important target for improvement, even in good CO2 -responsive cultivars.
Published: 2015

30. ALA10, a phospholipid flippase, controls FAD2/FAD3 desaturation of phosphatidylcholine in the ER, and affects chloroplast lipid composition in Arabidopsis thaliana

Author: Emeline Sautron, Eric Maréchal, Juliette Jouhet, Morgane Michaud, Catherine Albrieux, Maryse A. Block, Emmanuelle Dubots, César Botella, Laurence Boudière, Yoshiki Yamaryo-Botté, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-12-JSV2-0001,ChloroMitoLipid,Export de galactolipides des chloroplastes vers les mitochondries(2012), ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ANR-12-JSV2-0001,ChloroMitoLipid, ANR-10- LABX-49-01,Labex GRAL,Labex GRAL, Université Grenoble Alpes (COMUE) (UGA), ANR [ANR-12-JSV2-0001], and Labex Grenoble Alliance for Integrated Structural Cell Biology
Subjects: 0301 basic medicine, Fatty Acid Desaturases, Chloroplasts, Chloroplast membrane, Arabidopsis thaliana, Physiology, [SDV]Life Sciences [q-bio], Arabidopsis, Plant Science, chemistry.chemical_compound, ComputingMilieux_MISCELLANEOUS, Adenosine Triphosphatases, biology, food and beverages, Phosphatidic acid, Articles, Plants, Genetically Modified, Lipids, Cell biology, Biochemistry, Phosphatidylcholines, lipids (amino acids, peptides, and proteins), ALA10, Galactolipids biosynthesis, 03 medical and health sciences, Phosphatidylcholine, Genetics, ATPase, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Endomembrane system, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Membrane biogenesis, Arabidopsis Proteins, Galactolipids, Gene Expression Profiling, Galvestin-1, Glycerolipids, Flippase, Plant, biology.organism_classification, Lipid Metabolism, Plant Leaves, 030104 developmental biology, Metabolism, chemistry, Phospholipids translocation, Endoplasmic reticulum
Abstract: The biogenesis of photosynthetic membranes relies on galactoglycerolipids, which are synthesized via pathways that are dispatched over several cell compartments. This membrane biogenesis requires both trafficking of lipid intermediates and a tight homeostatic regulation. In this work, we address the role of ALA10 (for aminophospholipid ATPase), a P4-type ATPase, in a process counteracting the monogalactosyldiacylglycerol (MGDG) shortage in Arabidopsis (Arabidopsis thaliana) leaves. ALA10 can interact with protein partners, ALIS1 (for ALA-interacting subunit1) or ALIS5, leading to differential endomembrane localizations of the interacting proteins, close to the plasma membrane with ALIS1 or to chloroplasts with ALIS5. ALA10 interacts also with FATTY ACID DESATURASE2 (FAD2), and modification of ALA10 expression affects phosphatidylcholine (PC) fatty acyl desaturation by disturbing the balance between FAD2 and FAD3 activities. Modulation of ALA10 expression downstream impacts the fatty acyl composition of chloroplast PC. ALA10 expression also enhances leaf growth and improves the MGDG-PC ratio, possibly through MGDG SYNTHASE1 (MGD1) activation by phosphatidic acid. The positive effect of ALA10 on leaf development is significant in conditions such as upon treatment of plants with Galvestine-1, an inhibitor of MGDG synthases, or when plants are grown at chilling temperature.
Published: 2015

31. Chemical inhibitors of monogalactosyldiacylglycerol synthases in Arabidopsis thaliana

Author: Karen Loizeau, Maryse A. Block, Eric Maréchal, Emmanuelle Dubots, Olivier Bastien, Samia Aci, Bernard Rousseau, Jean-Christophe Cintrat, Cyrille Y. Botté, Denis Falconet, Yoshiki Yamaryo-Botté, Helene Hardre, Michael Deligny, Roman Lopez, Nadia Saidani, Jacques Joyard, Juliette Jouhet, Aymeric Roccia, Anne-Laure Bonneau, Laurent Brehelin, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie et de Technologies de Saclay (IBITECS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Dynamique des interactions membranaires normales et pathologiques (DIMNP), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de biophysique moléculaire (CBM), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Méthodes et Algorithmes pour la Bioinformatique (MAB), Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier (LIRMM), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), European Project, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), This work was supported by ANR-05-EMPB-017-01, ANR-06-MDCA-014, ANR-10-BLAN-1524-01 and ANR-2010-JCJC-1606-01 grants from the Agence Nationale de la Recherche, France. C.Y.B. was supported by a Marie Curie International Outgoing Fellowship action from the European Commission., Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Galactolipid, Arabidopsis thaliana, Arabidopsis, plant, monogalactosyldiacylglycerol, Plant Roots, monogalactosyldiacylglycerol synthase, 01 natural sciences, Gene Expression Regulation, Enzymologic, Small Molecule Libraries, MGDG, Structure-Activity Relationship, 03 medical and health sciences, Piperidines, Gene Expression Regulation, Plant, lipid, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Enzyme Inhibitors, Plastid, Molecular Biology, 030304 developmental biology, 0303 health sciences, Molecular Structure, biology, high throughput chemical screen, Galactolipids, Gene Expression Profiling, food and beverages, Cell Biology, Galactosyltransferases, biology.organism_classification, Plant Leaves, enzymatic inhibition, Diacylglycerol binding, Chloroplast, Biochemistry, Monogalactosyldiacylglycerol synthase, biology.protein, galactolipid, galvestine, 010606 plant biology & botany
Abstract: International audience; Monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the main lipids in photosynthetic membranes in plant cells. They are synthesized in the envelope surrounding plastids by MGD and DGD galactosyltransferases. These galactolipids are critical for the biogenesis of photosynthetic membranes, and they act as a source of polyunsaturated fatty acids for the whole cell and as phospholipid surrogates in phosphate shortage. Based on a high-throughput chemical screen, we have characterized a new compound, galvestine-1, that inhibits MGDs in vitro by competing with diacylglycerol binding. Consistent effects of galvestine-1 on Arabidopsis thaliana include root uptake, circulation in the xylem and mesophyll, inhibition of MGDs in vivo causing a reduction of MGDG content and impairment of chloroplast development. The effects on pollen germination shed light on the contribution of galactolipids to pollen-tube elongation. The whole-genome transcriptional response of Arabidopsis points to the potential benefits of galvestine-1 as a unique tool to study lipid homeostasis in plants.
Published: 2011

32. Turnover of branched actin filament networks by stochastic fragmentation with ADF/cofilin

Author: Laurent Blanchoin, Cristian Suarez, Rajaa Boujemaa-Paterski, Christopher J. Staiger, Christophe Guérin, Anne-Cécile Reymann, Jean-Louis Martiel, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Department of Biological Sciences and Bindley Bioscience Center, Purdue University [West Lafayette], Agence Nationale de la Recherche [ANR-08-BLAN-0012, ANR-08-SYSC-013], CEA, Office of Basic Energy Sciences, U.S. Department of Energy [DE-FG02-04ER15526], Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: MESH: Rabbits, Arp2/3 complex, Microfilament, actin dynamics, Actin remodeling of neurons, 0302 clinical medicine, Cell Movement, fragmentation, MESH: Animals, MESH: Cell Movement, 0303 health sciences, MESH: Kinetics, biology, cytoskeleton, Articles, Cofilin, actin binding protein, Microspheres, Cell biology, MESH: Destrin, Actin Cytoskeleton, MESH: Cattle, MESH: Actin Capping Proteins, Rabbits, Fluorescence Recovery After Photobleaching, assembly, capping protein, Actin Capping Proteins, nucleation, MESH: Microspheres, macromolecular substances, cell motility, Actin-Related Protein 2-3 Complex, 03 medical and health sciences, ADF/cofilin, Animals, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Actin-binding protein, Molecular Biology, 030304 developmental biology, Actin remodeling, Cell Biology, Actin cytoskeleton, Kinetics, MESH: Actin-Related Protein 2-3 Complex, Destrin, severing, biology.protein, Cattle, MDia1, MESH: Actin Cytoskeleton, Arp2/3, MESH: Fluorescence Recovery After Photobleaching, 030217 neurology & neurosurgery
Abstract: During actin-based motility, capping protein influences actin-depolymerizing factor (ADF)/cofilin binding that increases in space and time concomitant with the state of the nucleotide associated to the actin subunits. ADF/cofilin induces microscopic fragmentation of the actin network, which induces turnover through a macroscopic, stochastic dynamic mechanism., Cell motility depends on the rapid assembly, aging, severing, and disassembly of actin filaments in spatially distinct zones. How a set of actin regulatory proteins that sustains actin-based force generation during motility work together in space and time remains poorly understood. We present our study of the distribution and dynamics of Arp2/3 complex, capping protein (CP), and actin-depolymerizing factor (ADF)/cofilin in actin “comet tails,” using a minimal reconstituted system with nucleation-promoting factor (NPF)-coated beads. The Arp2/3 complex concentrates at nucleation sites near the beads as well as in the first actin shell. CP colocalizes with actin and is homogeneously distributed throughout the comet tail; it serves to constrain the spatial distribution of ATP/ADP-Pi filament zones to areas near the bead. The association of ADF/cofilin with the actin network is therefore governed by kinetics of actin assembly, actin nucleotide state, and CP binding. A kinetic simulation accurately validates these observations. Following its binding to the actin networks, ADF/cofilin is able to break up the dense actin filament array of a comet tail. Stochastic severing by ADF/cofilin loosens the tight entanglement of actin filaments inside the comet tail and facilitates turnover through the macroscopic release of large portions of the aged actin network.
Published: 2011

33. Actin dynamics in plant cells: a team effort from multiple proteins orchestrates this very fast-paced game

Author: Rajaa Boujemaa-Paterski, Laurent Blanchoin, Christopher J. Staiger, Jessica L. Henty, Parul Khurana, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Biological Sciences [Lafayette IN], Purdue University [West Lafayette], Department of Biological Sciences and Bindley Bioscience Center, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
Subjects: 0106 biological sciences, review, MESH: Plants, Arp2/3 complex, macromolecular substances, Plant Science, MESH: Actins, Microfilament, 01 natural sciences, actin dynamics, 03 medical and health sciences, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Cytoskeleton, plant cell, Actin, Plant Proteins, 030304 developmental biology, 0303 health sciences, Total internal reflection fluorescence microscope, MESH: Plant Proteins, biology, Actin remodeling, cytoskeleton, in vitro, Plants, actin binding protein, Actin cytoskeleton, Plant cell, Actins, Cell biology, in vivo, Biophysics, biology.protein, 010606 plant biology & botany
Abstract: International audience; Gazing at a giant redwood tree in the Pacific Northwest, that has grown to enormous heights over centuries, does little to convince one that plants are built for speed and versatility. Even at the cellular level, a system of polymers-the cell skeleton or cytoskeleton-integrates signals and generates subcellular structures spanning scales of a few nanometers to hundreds of micrometers that coordinate cell growth. The term cytoskeleton itself connotes a stable structure. Clearly, this is not the case. Recent studies using advanced imaging modalities reveal the plant actin cytoskeleton to be a highly dynamic, ever changing assemblage of polymers. These insights along with growing evidence about the biochemical/biophysical properties of plant cytoskeletal polymers, especially those obtained by single filament imaging and reconstituted systems of purified proteins analyzed by total internal reflection fluorescence microscopy, allow the generation of a unique model for the dynamic turnover of actin filaments, termed stochastic dynamics. Here, we review several significant advances and highlight opportunities that will position plants at the vanguard of research on actin organization and turnover. A challenge for the future will be to apply the power of reverse-genetics in several model organisms to test the molecular details of this new model.
Published: 2010

34. MASCP Gator: An Aggregation Portal for the Visualization of Arabidopsis Proteomics Data

Author: Ian Castleden, Stefanie Wienkoop, Matthias Hirsch-Hoffmann, Hirofumi Nakagami, Klaas J. van Wijk, Sandra K. Tanz, Christophe Bruley, Norbert Rolland, Joshua L. Heazlewood, Sacha Baginsky, Steven P. Briggs, Wilhelm Gruissem, A. Harvey Millar, R R Schmidt, Katja Baerenfaller, Alexandra M. E. Jones, Hiren J. Joshi, Waltraud X. Schulze, Volker Egelhofer, Tetsuro Toyoda, Wolfram Weckwerth, Qi Sun, Joint BioEnergy Institute, Department of Biology, Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Max Planck Institute of Molecular Plant Physiology (MPI-MP), Max-Planck-Gesellschaft, Department of plant Biology, Cornell University, Molecular Systems Biology, universite de Vienne, Laboratoire d'Etude de la Dynamique des Proteomes, Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Biosciences et de Biotechnologies de Grenoble (ex-IRTSV) (BIG), Institut National de la Santé et de la Recherche Médicale (INSERM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes (UGA), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), RIKEN Plant Science Center and RIKEN Bioinformatics and Systems Engineering Division, The Sainsbury Laboratory, Sainsbury Laboratory, Division of Biology, University of California [San Diego] (UC San Diego), University of California-University of California, Centre of Excellence for Computational Systems Biology, The University of Western Australia (UWA), Australian Research Council Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks, Cornell University [New York], Laboratoire d'étude de la dynamique des protéomes (LEDyP), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), The Sainsbury Laboratory [Norwich] (TSL), University of California (UC)-University of California (UC), U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research [DE-AC02-05CH11231], AGRON-OMICS [LSHG-CT-2006-037704], Australian Research Council, Australian Research Council Centre of Excellence in Plant Energy Biology, Ministry of Education, Culture, Sports, Science and Technology [21770059], Institut National de la Santé et de la Recherche Médicale (INSERM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
Subjects: 0106 biological sciences, Bioinformatics, Physiology, Research areas, Arabidopsis, plant, Plant Science, Proteomics, 01 natural sciences, World Wide Web, User-Computer Interface, 03 medical and health sciences, proteomics, Resource (project management), online resources, Genetics, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Phosphorylation, Databases, Protein, database, 030304 developmental biology, Internet, 0303 health sciences, biology, Arabidopsis Proteins, business.industry, data mining, Hyperlink, biology.organism_classification, Visualization, Identification (information), information networks, aggregator, The Internet, business, Protein Kinases, 010606 plant biology & botany
Abstract: Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (H.J.J., J.L.H.); Department of Biology, Eidgenossisch Technische Hochschule Zurich, CH-8092 Zurich, Switzerland (M. H.-H., K. B., W. G.); Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany (S. B.); Max-Planck Institute for Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (R. S., W. X. S.); Department of Plant Biology, Cornell University, Ithaca, New York 14853 (Q. S., K.J.v.W.); Molecular Systems Biology, University of Vienna, 1090 Vienna, Austria (V. E., S. W., W. W.); Institut National de la Sante et de la Recherche Medicale, Laboratoire d'Etude de la Dynamique des Proteomes, U880, F-38000 Grenoble, France (C. B.); Commissariat a l'Energie Atomique et aux Energies Alternatives, Direction des Sciences du Vivant, Institut de Recherches en Technologies et Sciences pour le Vivant, F-38000 Grenoble, France (C.B., N.R.); Universite Joseph Fourier, F-38000 Grenoble, France (C. B., N.R.); CNRS, Laboratoire de Physiologie Cellulaire Vegetale, UMR5168, F-38000 Grenoble, France (N.R.); INRA, UMR1200, F-38000 Grenoble, France (N.R.); RIKEN Plant Science Center and RIKEN Bioinformatics and Systems Engineering Division, Tsurumi-ku, Yokohama 230-0045, Japan (T.T., H.N.); The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom (A.M.J.); Division of Biology, University of California San Diego, La Jolla, California 92093 (S.P.B.); and Centre of Excellence for Computational Systems Biology (I.C.) and Australian Research Council Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (I.C., S.K.T., A.H.M.), University of Western Australia, Crawley 6009, Western Australia, Australia
Published: 2010

35. Nonflowering Plants Possess a Unique Folate-Dependent Phenylalanine Hydroxylase That Is Localized in Chloroplasts

Author: Romain Fouquet, Richard Haas, Alexandre Noiriel, Lloyd W. Sumner, Wolfgang Frank, Karen Loizeau, Andrew D. Hanson, Ralf Reski, Anne Pribat, John M. Davis, Alison M. Morse, Mohamed Bedair, Stéphane Ravanel, Horticultural Sciences Department, University of Florida [Gainesville], School of Forest Resources and Conservation, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Plant Biotechnology, University of Freiburg [Freiburg], Plant Biology Division, Samuel Roberts Noble Foundation, University of Florida [Gainesville] (UF), School of Forest Resources and Conservation [Gainesville] (UF|IFAS|FFGS), Institute of Food and Agricultural Sciences [Gainesville] (UF|IFAS), University of Florida [Gainesville] (UF)-University of Florida [Gainesville] (UF), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), The Samuel Roberts Noble Foundation, USDA National Institute of Food and Agriculture (2008-35318-04589), C.V. Griffin, Sr. Foundation, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0106 biological sciences, Chloroplasts, Physcomitrella, Chlamydomonas reinhardtii, plant, Plant Science, phylogeny, MESH: Bryopsida, 01 natural sciences, MESH: Recombinant Proteins, chemistry.chemical_compound, subcellular localization, Aromatic amino acids, Plant Proteins, MESH: Genetic Complementation Test, 0303 health sciences, MESH: Plant Proteins, biology, MESH: Hydro-Lyases, food and beverages, bioinformatics, Recombinant Proteins, Chloroplast, Complementation, tetrahydropterin, Biochemistry, homogentisate pathway, MESH: Computational Biology, Phenylalanine hydroxylase, Molecular Sequence Data, MESH: Pterins, phenylalanine hydroxylase, phenylpropanoid, folate, Physcomitrella patens, MESH: Folic Acid, In Brief, moss, 03 medical and health sciences, Folic Acid, chloroplast, evolution, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Hydro-Lyases, 030304 developmental biology, MESH: Chloroplasts, MESH: Molecular Sequence Data, Genetic Complementation Test, Computational Biology, cofactor, Cell Biology, aromatic aminoacid hydroxylase, Pinus, biology.organism_classification, Bryopsida, Pterins, enzyme, chemistry, kinetics, Dehydratase, biology.protein, metabolism, 010606 plant biology & botany
Abstract: Tetrahydropterin-dependent aromatic amino acid hydroxylases (AAHs) are known from animals and microbes but not plants. A survey of genomes and ESTs revealed AAH-like sequences in gymnosperms, mosses, and algae. Analysis of full-length AAH cDNAs from Pinus taeda, Physcomitrella patens, and Chlamydomonas reinhardtii indicated that the encoded proteins form a distinct clade within the AAH family. These proteins were shown to have Phe hydroxylase activity by functional complementation of an Escherichia coli Tyr auxotroph and by enzyme assays. The P. taeda and P. patens AAHs were specific for Phe, required iron, showed Michaelian kinetics, and were active as monomers. Uniquely, they preferred 10-formyltetrahydrofolate to any physiological tetrahydropterin as cofactor and, consistent with preferring a folate cofactor, retained activity in complementation tests with tetrahydropterin-depleted E. coli host strains. Targeting assays in Arabidopsis thaliana mesophyll protoplasts using green fluorescent protein fusions, and import assays with purified Pisum sativum chloroplasts, indicated chloroplastic localization. Targeting assays further indicated that pterin-4a-carbinolamine dehydratase, which regenerates the AAH cofactor, is also chloroplastic. Ablating the single AAH gene in P. patens caused accumulation of Phe and caffeic acid esters. These data show that nonflowering plants have functional plastidial AAHs, establish an unprecedented electron donor role for a folate, and uncover a novel link between folate and aromatic metabolism.
Published: 2010

36. Electrochromism: a useful probe to study algal photosynthesis

Author: Cécile Breyton, Giovanni Finazzi, Pierre Cardol, Benjamin Bailleul, Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génétique des Microorganismes, Université de Liège - Gembloux, Institut de biologie structurale (IBS - UMR 5075 ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie structurale (IBS - UMR 5075), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), and Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Département de Biologie - ENS Paris
Subjects: 0106 biological sciences, spectroscopy, Light, Algae, Acclimatization, MESH: Acclimatization, Plant Science, Photochemistry, Photosynthesis, 01 natural sciences, Biochemistry, Electron Transport, Light-harvesting complex, 03 medical and health sciences, Electron transfer, Electrochemistry, electrochromism, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, MESH: Electron Transport, Electrochemical gradient, MESH: Photosynthesis, 030304 developmental biology, 0303 health sciences, photosynthesis, MESH: Electrochemistry, ATP synthase, biology, Chemistry, Eukaryota, Cell Biology, General Medicine, electron transfer, electrochemical proton gradient, Electron transport chain, MESH: Light, ATP, MESH: Eukaryota, Thylakoid, biology.protein, Energy source, 010606 plant biology & botany
Abstract: International audience; In photosynthesis, electron transfer along the photosynthetic chain results in a vectorial transfer of protons from the stroma to the lumenal space of the thylakoids. This promotes the generation of an electrochemical proton gradient (Δμ(H)(+)), which comprises a gradient of electric potential (ΔΨ) and of proton concentration (ΔpH). The Δμ(H)(+) has a central role in the photosynthetic process, providing the energy source for ATP synthesis. It is also involved in many regulatory mechanisms. The ΔpH modulates the rate of electron transfer and triggers deexcitation of excess energy within the light harvesting complexes. The ΔΨ is required for metabolite and protein transport across the membranes. Its presence also induces a shift in the absorption spectra of some photosynthetic pigments, resulting in the so-called ElectroChromic Shift (ECS). In this review, we discuss the characteristic features of the ECS, and illustrate possible applications for the study of photosynthetic processes in vivo.
Published: 2010

37. Plant lipid-associated fibrillin proteins condition jasmonate production under photosynthetic stress

Author: Abir Youssef, Joël Gaffé, Yec’han Laizet, Maryse A. Block, Dominique Pontier, Jean-Pierre Alcaraz, Eric Maréchal, Tony R. Larson, Marcel Kuntz, Plastes et Différenciation Cellulaire (PDC), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), CNAP, Department of Biology, University of York [York, UK], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0106 biological sciences, plastoglobule, Photoinhibition, Arabidopsis thaliana, Plastoglobule, thylakoid, Arabidopsis, plant, Plant Science, 01 natural sciences, Anthocyanins, chemistry.chemical_compound, Jasmonate, Photosynthesis, plastid, 0303 health sciences, Jasmonic acid, Microfilament Proteins, food and beverages, Chloroplast, Biochemistry, Thylakoid, RNA Interference, jasmonic acid biosynthesis, triacylglycerol, photooxidative stress, fibrillin, Cyclopentanes, Biology, lipid associated protein, Fibrillins, 03 medical and health sciences, chloroplast, Microscopy, Electron, Transmission, Stress, Physiological, Genetics, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Oxylipins, Plastid, 030304 developmental biology, Arabidopsis Proteins, fungi, photosystem II, Photosystem II Protein Complex, Cell Biology, biology.organism_classification, chemistry, photosynthesis acclimation, 010606 plant biology & botany
Abstract: International audience; Summary The role of a subfamily of lipid globule-associated proteins, referred to as plant fibrillins (FIB1a, -1b, -2), was determined using a RNA interference (RNAi) strategy. We show that Arabidopsis plants with reduced levels of these plastid structural proteins are impaired in long-term acclimation to environmental constraint, namely photooxidative stress imposed by high light combined with cold. As a result, their photosynthetic apparatus is inefficiently protected. This leads to the prevalence of an abnormal granal and stromal membrane arrangement, as well as higher photosystem II photoinhibition under stress. The visible phenotype of FIB1-2 RNAi lines also includes retarded shoot growth and a deficit in anthocyanin accumulation under stress. All examined phenotypic effects of lower FIB levels are abolished by jasmonate (JA) treatment. An atypical expression pattern of several JA-induced genes was observed in RNAi plants. A JA-deficient mutant was found to share similar stress phenotypic characteristics with FIB RNAi plants. We conclude a new physiological role for JA, namely acclimation of chloroplasts, and that light/cold stress-related JA biosynthesis is conditioned by the accumulation of plastoglobule-associated FIB1-2 proteins. Consistent correlative data suggest that this FIB effect is mediated by plastoglobule (and triacylglycerol) accumulation as the potential site for initiating the chloroplast stress-related JA biosynthesis.
Published: 2010

38. Chloroplast Proteomics and the Compartmentation of Plastidial Isoprenoid Biosynthetic Pathways

Author: Daphné Seigneurin-Berny, Norbert Rolland, Jérôme Garin, Christophe Masselon, Myriam Ferro, Jacques Joyard, Daniel Salvi, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'étude de la dynamique des protéomes (LEDyP), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
Subjects: Chlorophyll, Proteomics, 0106 biological sciences, Chloroplasts, proteome, Arabidopsis, plant, Plant Science, Biology, 01 natural sciences, isoprenoid biosynthesis, 03 medical and health sciences, chloroplast, Stroma, subcellular localization, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Amino Acid Sequence, Plastids, Plastid, Databases, Protein, Molecular Biology, Plant Proteins, 030304 developmental biology, 0303 health sciences, Sequence Homology, Amino Acid, food and beverages, metabolic pathway, Chloroplast, Biochemistry, Plant protein, Thylakoid, Proteome, Chloroplast Proteins, metabolism, 010606 plant biology & botany
Abstract: International audience; Recent advances in the proteomic field have allowed high-throughput experiments to be conducted on chloroplast samples. Many proteomic investigations have focused on either whole chloroplast or sub-plastidial fractions. To date, the Plant Protein Database (PPDB, Sun et al., 2009) presents the most exhaustive chloroplast proteome available online. However, the accurate localization of many proteins that were identified in different sub-plastidial compartments remains hypothetical. Ferro et al. (2009) went a step further into the knowledge of Arabidopsis thaliana chloroplast proteins with regards to their accurate localization within the chloroplast by using a semi-quantitative proteomic approach known as spectral counting. Their proteomic strategy was based on the accurate mass and time tags (AMT) database approach and they built up AT_CHLORO, a comprehensive chloroplast proteome database with sub-plastidial localization and curated information on envelope proteins. Comparing these two extensive databases, we focus here on about 100 enzymes involved in the synthesis of chloroplast-specific isoprenoids. Well known pathways (i.e. compartmentation of the methyl erythritol phosphate biosynthetic pathway, of tetrapyrroles and chlorophyll biosynthesis and breakdown within chloroplasts) validate the spectral counting-based strategy. The same strategy was then used to identify the precise localization of the biosynthesis of carotenoids and prenylquinones within chloroplasts (i.e. in envelope membranes, stroma, and/or thylakoids) that remains unclear until now.
Published: 2009

39. Drug inhibition of HDAC3 and epigenetic control of differentiation in Apicomplexa parasites

Author: Patricia Baldacci, Hervé Pelloux, Olivier Bastien, Anthony Bouillon, Philippe Ortet, Alexandre Bougdour, Jean-Christophe Barale, Mohamed-Ali Hakimi, Robert Ménard, Danièle Maubon, Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] (LAPM), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire de parasitologie-mycologie, CHU Grenoble, Biologie et Génétique du Paludisme, Institut Pasteur [Paris], Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Immunologie moléculaire des parasites, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris] (IP), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: MESH: Cell Differentiation, Plasmodium, medicine.drug_class, Cellular differentiation, MESH: Apicomplexa, Immunology, Peptides, Cyclic, Article, Histone Deacetylases, Apicomplexa, 03 medical and health sciences, parasitic diseases, medicine, Animals, Immunology and Allergy, MESH: Animals, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Epigenetics, Conserved Sequence, MESH: Peptides, Cyclic, 030304 developmental biology, Regulation of gene expression, Genetics, Cyclic, 0303 health sciences, MESH: Conserved Sequence, biology, MESH: Plasmodium, 030306 microbiology, MESH: Toxoplasma, Histone deacetylase inhibitor, Cell Differentiation, biology.organism_classification, MESH: Gene Expression Regulation, 3. Good health, Cell biology, Histone Deacetylase Inhibitors, MESH: Histone Deacetylases, Trichostatin A, Histone, Gene Expression Regulation, biology.protein, Protozoa, Peptides, Toxoplasma, medicine.drug
Abstract: International audience; Plasmodium and Toxoplasma are parasites of major medical importance that belong to the Apicomplexa phylum of protozoa. These parasites transform into various stages during their life cycle and express a specific set of proteins at each stage. Although little is yet known of how gene expression is controlled in Apicomplexa, histone modifications, particularly acetylation, are emerging as key regulators of parasite differentiation and stage conversion. We investigated the anti-Apicomplexa effect of FR235222, a histone deacetylase inhibitor (HDACi). We show that FR235222 is active against a variety of Apicomplexa genera, including Plasmodium and Toxoplasma, and is more potent than other HDACi's such as trichostatin A and the clinically relevant compound pyrimethamine. We identify T. gondii HDAC3 (TgHDAC3) as the target of FR235222 in Toxoplasma tachyzoites and demonstrate the crucial role of the conserved and Apicomplexa HDAC-specific residue TgHDAC3 T99 in the inhibitory activity of the drug. We also show that FR235222 induces differentiation of the tachyzoite (replicative) into the bradyzoite (nonreplicative) stage. Additionally, via its anti-TgHDAC3 activity, FR235222 influences the expression of approximately 370 genes, a third of which are stage-specifically expressed. These results identify FR235222 as a potent HDACi of Apicomplexa, and establish HDAC3 as a central regulator of gene expression and stage conversion in Toxoplasma and, likely, other Apicomplexa.
Published: 2009

40. A Proteomic Survey of Chlamydomonas reinhardtii Mitochondria Sheds New Light on the Metabolic Plasticity of the Organelle and on the Nature of the -Proteobacterial Mitochondrial Ancestor

Author: Brigitte Gontero, Oliver Deusch, Jérôme Garin, Marianne Tardif, Norbert Rolland, Sabine Brugière, Tal Dagan, Jacques Joyard, William Martin, Annie Adrait, Robert van Lis, Lauriane Kuhn, Ariane Atteia, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude de la dynamique des protéomes (LEDyP), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institute of Botany, Heinrich-Heine-Universität Düsseldorf [Düsseldorf], Bioénergétique et Ingénierie des Protéines (BIP ), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
Subjects: 0106 biological sciences, carbon metabolism, Algae, proteome, Chlamydomonas reinhardtii, nucleotide metabolism, Mitochondrion, phylogeny, 01 natural sciences, Genome, Oxidative Phosphorylation, 03 medical and health sciences, evolution, Organelle, Genetics, Animals, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Molecular Biology, Ecology, Evolution, Behavior and Systematics, Alphaproteobacteria, 030304 developmental biology, 0303 health sciences, biology, Chlamydomonas, metabolic pathway, sequence homology, bioinformatics, Vitamin biosynthesis, biology.organism_classification, Biological Evolution, Cell biology, mitochondria, enzyme, vitamin biosynthesis, targeting prediction, Proteome, Eukaryote, protein import, protein, metabolism, 010606 plant biology & botany
Abstract: Mitochondria play a key role in the life and death of eukaryotic cells, yet the full spectrum of mitochondrial functions is far from being fully understood, especially in photosynthetic organisms. To advance our understanding of mitochondrial functions in a photosynthetic cell, an extensive proteomic survey of Percoll-purified mitochondria from the metabolically versatile, hydrogen-producing green alga Chlamydomonas reinhardtii was performed. Different fractions of purified mitochondria from Chlamydomonas cells grown under aerobic conditions were analyzed by nano-liquid chromatography-electrospray ionization-mass spectrometry after protein separation on sodium dodecyl sulfate polyacrylamide gel electrophoresis or on blue-native polyacrylamide gel electrophoresis. Of the 496 nonredundant proteins identified, 149 are known or predicted to reside in other cellular compartments and were thus excluded from the molecular and evolutionary analyses of the Chlamydomonas proteome. The mitochondrial proteome of the photosynthetic alga reveals important lineage-specific differences with other mitochondrial proteomes, reflecting the high metabolic diversity of the organelle. Some mitochondrial metabolic pathways in Chlamydomonas appear to combine typical mitochondrial enzymes and bacterial-type ones, whereas others are unknown among mitochondriate eukaryotes. The comparison of the Chlamydomonas proteins to their identifiable homologs predicted from 354 sequenced genomes indicated that Arabidopsis is the most closely related nonalgal eukaryote. Furthermore, this phylogenomic analysis shows that free-living alpha-proteobacteria from the metabolically versatile orders Rhizobiales and Rhodobacterales better reflect the gene content of the ancestor of the chlorophyte mitochondria than parasitic alpha-proteobacteria with reduced and specialized genomes.
Published: 2009

41. Nitrite–nitric oxide control of mitochondrial respiration at the frontier of anoxia

Author: Ljudmilla Borisjuk, David Macherel, Marie-Hélène Avelange-Macherel, Abdelilah Benamar, H. Ahmed Mostefai, Gilles Curien, Ramaroson Andriantsitohaina, Hardy Rolletschek, Physiologie Moléculaire des Semences (PMS), Université d'Angers (UA)-Institut National de la Recherche Agronomique (INRA)-Institut National d'Horticulture, Leibniz Institute of Plant Genetics and Crop Plant Research [Gatersleben] (IPK-Gatersleben), Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Biologie Neurovasculaire Intégrée (BNVI), Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Institut für Pflanzengenetik und Kulturpflanzenforschung, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut National d'Horticulture-Institut National de la Recherche Agronomique (INRA)-Université d'Angers (UA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0106 biological sciences, Bioenergetics, Nitrite, Cell Respiration, Biophysics, plant, Mitochondrion, bioenergetics, 01 natural sciences, Biochemistry, mathematical analysis, Nitric oxide, 03 medical and health sciences, chemistry.chemical_compound, Oxygen homeostasis, Respiration, Animals, Cytochrome c oxidase, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Nitrites, Pisum sativum, 030304 developmental biology, 0303 health sciences, biology, hypoxia, Electron Spin Resonance Spectroscopy, Peas, anoxia, Cell Biology, Plants, Cell biology, Oxygen, mitochondria, chemistry, germination, Coenzyme Q – cytochrome c reductase, Seeds, Mammalia, biology.protein, Oxidation-Reduction, seed, respiration, 010606 plant biology & botany
Abstract: International audience; Actively respiring animal and plant tissues experience hypoxia because of mitochondrial O(2) consumption. Controlling oxygen balance is a critical issue that involves in mammals hypoxia-inducible factor (HIF) mediated transcriptional regulation, cytochrome oxidase (COX) subunit adjustment and nitric oxide (NO) as a mediator in vasodilatation and oxygen homeostasis. In plants, NO, mainly derived from nitrite, is also an important signalling molecule. We describe here a mechanism by which mitochondrial respiration is adjusted to prevent a tissue to reach anoxia. During pea seed germination, the internal atmosphere was strongly hypoxic due to very active mitochondrial respiration. There was no sign of fermentation, suggesting a down-regulation of O(2) consumption near anoxia. Mitochondria were found to finely regulate their surrounding O(2) level through a nitrite-dependent NO production, which was ascertained using electron paramagnetic resonance (EPR) spin trapping of NO within membranes. At low O(2), nitrite is reduced into NO, likely at complex III, and in turn reversibly inhibits COX, provoking a rise to a higher steady state level of oxygen. Since NO can be re-oxidized into nitrite chemically or by COX, a nitrite-NO pool is maintained, preventing mitochondrial anoxia. Such an evolutionarily conserved mechanism should have an important role for oxygen homeostasis in tissues undergoing hypoxia.
Published: 2008
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42. Tocotrienols, the Unsaturated Forms of Vitamin E, Can Function as Antioxidants and Lipid Protectors in Tobacco Leaves

Author: Michel Havaux, Brigitte Ksas, Michel Matringe, Pascal Rey, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
Subjects: 0106 biological sciences, plastoglobule, antioxidant, Antioxidant, Photoinhibition, Physiology, medicine.medical_treatment, Nicotiana tabacum, thylakoid, plant, vitamin E, Plant Science, hydroxyphenylpyruvate dioxygenase, 01 natural sciences, Antioxidants, Lipid peroxidation, chemistry.chemical_compound, Photosynthesis, Carotenoid, transgenic plant, chloroplast envelope, 2. Zero hunger, chemistry.chemical_classification, 0303 health sciences, biology, food and beverages, Plants, Genetically Modified, membrane lipid, Biochemistry, prephenate dehydrogenase, Electrophoresis, Polyacrylamide Gel, Tocotrienol, photooxidative stress, Research Article, Blotting, Western, Molecular Sequence Data, Electron Transport, 03 medical and health sciences, Tobacco, Genetics, medicine, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, tocotrienol, 030304 developmental biology, leaf, Vitamin E, chilling stress, fungi, Photosystem II Protein Complex, Lipid Metabolism, biology.organism_classification, Plant Leaves, Oxidative Stress, chemistry, 010606 plant biology & botany
Abstract: Vitamin E is a generic term for a group of lipid-soluble antioxidant compounds, the tocopherols and tocotrienols. While tocotrienols are considered as important vitamin E components in humans, with functions in health and disease, the protective functions of tocotrienols have never been investigated in plants, contrary to tocopherols. We took advantage of the strong accumulation of tocotrienols in leaves of double transgenic tobacco (Nicotiana tabacum) plants that coexpressed the yeast (Saccharomyces cerevisiae) prephenate dehydrogenase gene (PDH) and the Arabidopsis (Arabidopsis thaliana) hydroxyphenylpyruvate dioxygenase gene (HPPD) to study the antioxidant function of those compounds in vivo. In young leaves of wild-type and transgenic tobacco plants, the majority of vitamin E was stored in thylakoid membranes, while plastoglobules contained mainly δ-tocopherol, a very minor component of vitamin E in tobacco. However, the vitamin E composition of plastoglobules was observed to change substantially during leaf aging, with α-tocopherol becoming the major form. Tocotrienol accumulation in young transgenic HPPD-PDH leaves occurred without any significant perturbation of photosynthetic electron transport. Tocotrienols noticeably reinforced the tolerance of HPPD-PDH leaves to high light stress at chilling temperature, with photosystem II photoinhibition and lipid peroxidation being maintained at low levels relative to wild-type leaves. Very young leaves of wild-type tobacco plants turned yellow during chilling stress, because of the strongly reduced levels of chlorophylls and carotenoids, and this phenomenon was attenuated in transgenic HPPD-PDH plants. While sugars accumulated similarly in young wild-type and HPPD-PDH leaves exposed to chilling stress in high light, a substantial decrease in tocotrienols was observed in the transgenic leaves only, suggesting vitamin E consumption during oxygen radical scavenging. Our results demonstrate that tocotrienols can function in vivo as efficient antioxidants protecting membrane lipids from peroxidation.
Published: 2008

43. Lipidomic Analysis of Toxoplasma gondii Reveals Unusual Polar Lipids

Author: Ruth Welti, Cyrille Y. Botté, Craig W. Roberts, Sarah A. Wernimont, Alexis A. Sparks, Rima McLeod, Michael J. Kirisits, Giorgis Isaac, Mary R. Roth, Eric Maréchal, Ernie Mui, Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Departments of Ophthalmology and Visual Sciences, University of Chicago, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde [Glasgow], Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Strathclyde, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Spectrometry, Mass, Electrospray Ionization, phosphatidylserine, Membrane lipids, Toxoplasma gondii, electrospray ionization tandem mass spectrometry, human parasite, Biochemistry, Article, sphingomyelin, 03 medical and health sciences, chemistry.chemical_compound, ceramide phosphoethanolamine, Lipid biosynthesis, Phosphatidylcholine, parasitic diseases, Animals, Humans, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, phosphatidylcholine, Fatty acid synthesis, 030304 developmental biology, chemistry.chemical_classification, 0303 health sciences, biology, lipid biosynthesis, 030302 biochemistry & molecular biology, Fatty acid, Phosphatidylserine, biology.organism_classification, Lipids, polar lipid, chemistry, lipids (amino acids, peptides, and proteins), fatty acid, Sphingomyelin, Toxoplasma, metabolism
Abstract: Analysis of the polar lipids of Toxoplasma gondii by electrospray ionization tandem mass spectrometry provides a detailed picture of the lipid molecular species of this parasitic protozoan. Most notably, T. gondii contains a relatively high level, estimated to about 2% of the total polar lipid, of ceramide phosphoethanolamine. The ceramide phosphoethanolamine has a fatty amide profile with only 16- and 18-carbon species. Compared with the host fibroblasts in which it was grown, T. gondii also has higher levels of phosphatidylcholine, but lower levels of sphingomyelin and phosphatidylserine. Analysis at the molecular species level indicated that T. gondii has greater amounts of shorter-chain fatty acid in its polar lipid molecular species than the host fibroblasts. Shorter-chain fatty acids with a combined total of 30 or fewer acyl carbons make up 21% of Toxoplasma’s, but only 3% of the host’s, diacyl phosphatidylcholine. Furthermore, diacyl phosphatidylcholine with two saturated acyl chains with 12, 14, or 16 carbons make up over 11% of parasite phosphatidylcholine, but less than 3% of the host phosphatidylcholine molecular species. The distinctive T. gondii tachyzoite lipid profile may be particularly suited to the function of parasitic membranes and the interaction of the parasite with the host cell and the host’s immune system. Combined with T. gondii genomic data, these lipidomic data will assist in elucidation of metabolic pathways for lipid biosynthesis in this important human pathogen.
Published: 2007

44. Actin-Filament Stochastic Dynamics Mediated by ADF/Cofilin

Author: Julien Berro, Rajaa Boujemaa-Paterski, Laurent Blanchoin, Alphée Michelot, Christopher J. Staiger, Christophe Guérin, Jean-Louis Martiel, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), TIMB, Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525 (TIMC-IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Department of Biological Sciences and Bindley Bioscience Center, Purdue University [West Lafayette], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)
Subjects: total internal reflection fluroescence microscopy, time lapse evanescent wave microscopy, Arp2/3 complex, cofilin, macromolecular substances, Biology, Models, Biological, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, Actin remodeling of neurons, 0302 clinical medicine, Biomimetics, Humans, profilin, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Cytoskeleton, 030304 developmental biology, Stochastic Processes, 0303 health sciences, SYSBIO, Agricultural and Biological Sciences(all), actin polymerization, Biochemistry, Genetics and Molecular Biology(all), Actin remodeling, cytoskeleton, Cofilin, Cell biology, Actin Cytoskeleton, Kinetics, actin depolymerizing factors, Treadmilling, Profilin, biology.protein, CELLBIO, MDia1, severing activity, General Agricultural and Biological Sciences, 030217 neurology & neurosurgery, TIRF microscopy
Abstract: This article has been presented in the Journal Current Biology as the Featured Article, freely available for all readers: "Here, Blanchoin and colleagues combined evanescent-wave microscopy with a biomimetic system to visualize individual actin-filament dynamics in real time. This analysis suggests that the control of actin dynamics is dominated by ADF/cofilin-mediated filament severing that induces a stochastic behavior upon individual actin filaments, and such a behavior, in combination with stabilization of filaments in bundles, could account for the formation of actin-based structures."; International audience; BACKGROUND: The rapid dynamics of actin filaments is a fundamental process that powers a large number of cellular functions. However, the basic mechanisms that control and coordinate such dynamics remain a central question in cell biology. To reach beyond simply defining the inventory of molecules that control actin dynamics and to understand how these proteins act synergistically to modulate filament turnover, we combined evanescent-wave microscopy with a biomimetic system and followed the behavior of single actin filaments in the presence of a physiologically relevant mixture of accessory proteins. This approach allows for the real-time visualization of actin polymerization and age-dependent filament severing. RESULTS: In the presence of actin-depolymerizing factor (ADF)/cofilin and profilin, actin filaments with a processive formin attached at their barbed ends were observed to oscillate between stochastic growth and shrinkage phases. Fragmentation of continuously growing actin filaments by ADF/cofilin is the key mechanism modulating the prominent and frequent shortening events. The net effect of continuous actin polymerization, driven by a processive formin that uses profilin-actin, and of ADF/cofilin-mediating severing that trims the aged ends of the growing filaments is an up to 155-fold increase in the rate of actin-filament turnover in vitro in comparison to that of actin alone. Lateral contact between actin filaments dampens the dynamics and favors actin-cable formation. A kinetic simulation accurately validates these observations. CONCLUSIONS: Our proposed mechanism for the control of actin dynamics is dominated by ADF/cofilin-mediated filament severing that induces a stochastic behavior upon individual actin filaments. When combined with a selection process that stabilizes filaments in bundles, this mechanism could account for the emergence and extension of actin-based structures in cells.
Published: 2007

45. New Insights into the Unique Structure of the F0F1-ATP Synthase from the Chlamydomonad Algae Polytomella sp. and Chlamydomonas reinhardtii

Author: Robert van Lis, Georg Groth, Guillermo Mendoza-Hernández, Ariane Atteia, Institute of Botany, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Département de biochimie - Faculté de médecine, Université Nationale Autonome de Mexico, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Heinrich-Heine-Universität Düsseldorf [Düsseldorf], and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Hot Temperature, Algae, Physiology, Molecular Sequence Data, Chlamydomonas reinhardtii, plant, physicochemical properties, Plant Science, Mitochondrion, 01 natural sciences, 03 medical and health sciences, Protein structure, ATP synthase gamma subunit, Genetics, Animals, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Amino Acid Sequence, structure, Protein Structure, Quaternary, 030304 developmental biology, chemistry.chemical_classification, 0303 health sciences, biology, ATP synthase, Algal Proteins, Chlamydomonas, Polytomella, biology.organism_classification, mitochondria, Proton-Translocating ATPases, enzyme, Enzyme, chemistry, Biochemistry, biology.protein, Electrophoresis, Polyacrylamide Gel, Research Article, 010606 plant biology & botany
Abstract: In this study, we investigate the structure of the mitochondrial F(0)F(1)-ATP synthase of the colorless alga Polytomella sp. with respect to the enzyme of its green close relative Chlamydomonas reinhardtii. It is demonstrated that several unique features of the ATP synthase in C. reinhardtii are also present in Polytomella sp. The alpha- and beta-subunits of the ATP synthase from both algae are highly unusual in that they exhibit extensions at their N- and C-terminal ends, respectively. Several subunits of the Polytomella ATP synthase in the range of 9 to 66 kD have homologs in the green alga but do not have known equivalents as yet in mitochondrial ATP synthases of mammals, plants, or fungi. The largest of these so-called ASA (ATP Synthase-Associated) subunits, ASA1, is shown to be an extrinsic protein. Short heat treatment of isolated Polytomella mitochondria unexpectedly dissociated the otherwise highly stable ATP synthase dimer of 1,600 kD into subcomplexes of 800 and 400 kD, assigned as the ATP synthase monomer and F(1)-ATPase, respectively. Whereas no ASA subunits were found in the F(1)-ATPase, all but two were present in the monomer. ASA6 (12 kD) and ASA9 (9 kD), predicted to be membrane bound, were not detected in the monomer and are thus proposed to be involved in the formation or stabilization of the enzyme. A hypothetical configuration of the Chlamydomonad dimeric ATP synthase portraying its unique features is provided to spur further research on this topic.
Published: 2007

46. Microtubules self-repair in response to mechanical stress

Author: Manuel Théry, Karin John, Laurent Blanchoin, Jérémie Gaillard, Laura Schaedel, Maxence V. Nachury, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), LIPHY-DYFCOM, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Stanford University [Stanford], HFSP funding (RGY0088/2012), European Project: European Research Council, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), DYnamique des Fluides COmplexes et Morphogénèse [Grenoble] (DYFCOM-LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Stanford University, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
Subjects: Materials science, Mechanical stress, Nanotechnology, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Flagellum, Plasticity, Microtubules, Article, Softening, Microtubule, Tubulin, Lab-On-A-Chip Devices, medicine, Animals, Humans, General Materials Science, Cytoskeleton, Microtubule nucleation, biology, Mechanical Engineering, Cilium, Stiffness, General Chemistry, Condensed Matter Physics, Self repairing, Mechanics of Materials, Biophysics, biology.protein, Stress, Mechanical, medicine.symptom
Abstract: Supplementary information : Supplementary figure S1 – S8 Supplementary video 1 – 6 legends; International audience; Microtubules--which define the shape of axons, cilia and flagella, and provide tracks for intracellular transport--can be highly bent by intracellular forces, and microtubule structure and stiffness are thought to be affected by physical constraints. Yet how microtubules tolerate the vast forces exerted on them remains unknown. Here, by using a microfluidic device, we show that microtubule stiffness decreases incrementally with each cycle of bending and release. Similar to other cases of material fatigue, the concentration of mechanical stresses on pre-existing defects in the microtubule lattice is responsible for the generation of more extensive damage, which further decreases microtubule stiffness. Strikingly, damaged microtubules were able to incorporate new tubulin dimers into their lattice and recover their initial stiffness. Our findings demonstrate that microtubules are ductile materials with self-healing properties, that their dynamics does not exclusively occur at their ends, and that their lattice plasticity enables the microtubules' adaptation to mechanical stresses.
Published: 2015

47. Plastid RNA polymerases: orchestration of enzymes with different evolutionary origins controls chloroplast biogenesis during the plant life cycle

Author: Silva Lerbs-Mache, Fabien Chevalier, Monique Liebers, Thomas Pfannschmidt, Livia Merendino, Florence Courtois, Björn Grübler, Robert Blanvillain, Elisabeth Hommel, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), DFG [Pf323-4, Pf323-5], Universite Grenoble-Alpes, Labex GRAL (Grenoble Alliance for Integrated & Structural Biology), Physiologie cellulaire et végétale (LPCV), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Chloroplasts, plastid RNA polymerases, Physiology, [SDV]Life Sciences [q-bio], Plant Science, 01 natural sciences, Genome, 03 medical and health sciences, chemistry.chemical_compound, RNA polymerase, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, nucleo-plastid interaction, Plastid, Polymerase, 030304 developmental biology, Genetics, 0303 health sciences, Life Cycle Stages, Endosymbiosis, biology, food and beverages, RNA, DNA-Directed RNA Polymerases, Plants, biology.organism_classification, Chloroplast biogenesis, Biological Evolution, Enzyme Activation, chemistry, RNA, Plant, developmental regulation, gene expression, biology.protein, Eukaryote, Biogenesis, 010606 plant biology & botany
Abstract: International audience; Chloroplasts are the sunlight-collecting organelles of photosynthetic eukaryotes that energetically drive the biosphere of our planet. They are the base for all major food webs by providing essential photosynthates to all heterotrophic organisms including humans. Recent research has focused largely on an understanding of the function of these organelles, but knowledge about the biogenesis of chloroplasts is rather limited. It is known that chloroplasts develop from undifferentiated precursor plastids, the proplastids, in meristematic cells. This review focuses on the activation and action of plastid RNA polymerases, which play a key role in the development of new chloroplasts from proplastids. Evolutionarily, plastids emerged from the endosymbiosis of a cyanobacterium-like ancestor into a heterotrophic eukaryote. As an evolutionary remnant of this process, they possess their own genome, which is expressed by two types of plastid RNA polymerase, phage-type and prokaryotic-type RNA polymerase. The protein subunits of these polymerases are encoded in both the nuclear and plastid genomes. Their activation and action therefore require a highly sophisticated regulation that controls and coordinates the expression of the components encoded in the plastid and nucleus. Stoichiometric expression and correct assembly of RNA polymerase complexes is achieved by a combination of developmental and environmentally induced programmes. This review highlights the current knowledge about the functional coordination between the different types of plastid RNA polymerases and provides working models of their sequential expression and function for future investigations.
Published: 2015

48. ESCRT-III-Associated Protein ALIX Mediates High-Affinity Phosphate Transporter Trafficking to Maintain Phosphate Homeostasis in Arabidopsis

Author: Ximena Cardona-López, Charukesi Rajulu, Richard Bligny, Vicente Rubio, M. L. Irigoyen, Javier Paz-Ares, Elena Marin, María Isabel Puga, Niko Geldner, Laura Cuyas, Laurent Nussaume, Erica Gil, Centro Nacional de Biotecnología [Madrid] (CNB-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Plant Environmental Physiology and Stress Signaling (PEPSS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Department of Plant Molecular Biology, Université de Lausanne = University of Lausanne (UNIL), Spanish Ministry of Economy and Competitiveness (MINECO, National Research Program, Grants BIO2010-18820and BIO2013-46539-R, BIO2011-29085, INNPACTO Program, Grant IPT-310000-2010-9, CONSOLIDERProgram, Grant 2007-28317, PLANT-KBBEProgram, Grant EUI2008-03742), Department of Plant Molecular Genetics, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Signalisation de l'Adaptation des Végétaux à l'Environnement (SAVE), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université de Lausanne (UNIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Arabidopsis thaliana, Endosome, Protein cargoes, Mutant, Protein trafficking, Protein complexes, Plant Science, Vacuole, macromolecular substances, ESCRT, Phosphate homeostasis, Phosphate transporters, Arabidopsis, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Research Articles, biology, Vacuolar lumen, fungi, Cell Biology, Plant, biology.organism_classification, Cell biology, Transport protein, Endosomal sorting complexes required for transport, Metabolism, Membrane protein, Biogenesis
Abstract: International audience; Prior to the release of their cargoes into the vacuolar lumen, sorting endosomes mature into multivesicular bodies (MVBs) through the action of ENDOSOMAL COMPLEX REQUIRED FOR TRANSPORT (ESCRT) protein complexes. MVB-mediated sorting of high-affinity phosphate transporters (PHT1) to the vacuole limits their plasma membrane levels under phosphate-sufficient conditions, a process that allows plants to maintain phosphate homeostasis. Here, we describe ALIX, a cytosolic protein that associates with MVB by interacting with ESCRT-III subunit SNF7 and mediates PHT1;1 trafficking to the vacuole in Arabidopsis thaliana. We show that the partial loss-of-function mutant alix-1 displays reduced vacuolar degradation of PHT1;1. ALIX derivatives containing the alix-1 mutation showed reduced interaction with SNF7, providing a simple molecular explanation for impaired cargo trafficking in alix-1 mutants. In fact, the alix-1 mutation also hampered vacuolar sorting of the brassinosteroid receptor BRI1. We also show that alix-1 displays altered vacuole morphogenesis, implying a new role for ALIX proteins in vacuolar biogenesis, likely acting as part of ESCRT-III complexes. In line with a presumed broad target spectrum, the alix-1 mutation is pleiotropic, leading to reduced plant growth and late flowering, with stronger alix mutations being lethal, indicating that ALIX participates in diverse processes in plants essential for their life.
Published: 2015

49. Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms

Author: Judit Prihoda, Fabrice Rappaport, Denis Falconet, Stefano Santabarbara, Pierre Joliot, Benjamin Bailleul, Atsuko Tanaka, Pierre Cardol, Richard Bligny, Omer Murik, Chris Bowler, Paul G. Falkowski, Serena Flori, Dimitris Petroutsos, Leila Tirichine, Nicolas Berne, Anja Krieger-Liszkay, Giovanni Finazzi, Valeria Villanova, Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Physiologie membranaire et moléculaire du chloroplaste (PMMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Génétique et Physiologie des Microalgues, Université de Liège, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Fermentalg, Serv Bioenerget Biol Struct & Mécanisme, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Istituto di Biofisica, Consiglio Nazionale delle Ricerch, Collège de France (CdF (institution)), Region Rhone-Alpes (Cible project)- Marie Curie Initial Training Network Accliphot (FP7-PEPOPLE-2012-ITN, 316427)- CNRS Defi (ENRS 2013)- CEA Bioenergies program- Belgian Fonds de la Recherche Scientifique- Incentive Grant for Scientific Research F 4520- COSI ITN project, ANR-12-BIME-0005,DiaDomOil,Domestication des diatomées pour la production de biocarburants(2012), ANR-09-BLAN-0139,PhytAdapt,Adaptation du phytoplancton(2009), ANR-11-LABX-0011,DYNAMO,Dynamique des membranes transductrices d'énergie : biogénèse et organisation supramoléculaire.(2011), ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), European Project: 294823,EC:FP7:ERC,ERC-2011-ADG_20110310,DIATOMITE(2012), European Project: 287589,EC:FP7:KBBE,FP7-OCEAN-2011,MICRO B3(2012), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ANR: NT09_567009,Phytadapt,Phytadapt, ANR-11-LABX-0011/11-LABX-0011,DYNAMO,Dynamique des membranes transductrices d'énergie : biogénèse et organisation supramoléculaire.(2011), ANR: ANR-11-IDEX-0001-02,ANR-11-IDEX-0001-02, ANR-10-IDEX-0001-02/10-LABX-0054,MEMOLIFE,Memory in living systems: an integrated approach(2010), Institut de biologie de l'ENS Paris (IBENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Liège, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Bailleul B., Berne N., Murik O., Petroutsos D., Prihoda J., Tanaka A., Villanova V., Bligny R., Flori S., Falconet D., Krieger-Liszkay A., Santabarbara S., Rappaport F., Joliot P., Tirichine L., Falkowski P.G., Cardol P., Bowler C., Finazzi G., and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris
Subjects: Aquatic Organisms, chemistry.chemical_compound, Adenosine Triphosphate, Settore BIO/04 - Fisiologia Vegetale, CYCLIC ELECTRON FLOW, Plastids, Photosynthesis, PHAEODACTYLUM-TRICORNUTUM, Plant Proteins, chemistry.chemical_classification, Multidisciplinary, microalgae, Respiration, Carbon fixation, Energetic interactions, Proton-Motive Force, Mitochondria, metabolic mutant, Phenotype, ATP/NADPH ratio, OXYGEN PHOTOREDUCTION, Carbon dioxide, Oxidoreductases, Oxidation-Reduction, Ocean, Oceans and Seas, Electron flow, Marine eukaryotes, Biology, CHLAMYDOMONAS-REINHARDTII, Carbon cycle, Carbon Cycle, Mitochondrial Proteins, Energetic exchanges, Botany, Organic matter, Ecosystem, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, 14. Life underwater, Plastid, Diatoms, Chemiosmosis, fungi, ECS, Carbon Dioxide, chemistry, 13. Climate action, NADP
Abstract: International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies principally on a range of plastid-localized ATP generating processes. Here we show that diatoms regulate ATP/NADPH through extensive energetic exchanges between plastids and mitochondria. This interaction comprises the re-routing of reducing power generated in the plastid towards mitochondria and the import of mitochondrial ATP into the plastid, and is mandatory for optimized carbon fixation and growth. We propose that the process may have contributed to the ecological success of diatoms in the ocean.
Published: 2015

50. Identification of Early Nuclear Target Genes of Plastidial Redox Signals that Trigger the Long-Term Response of Arabidopsis to Light Quality Shifts

Author: Christine Gläßer, Klaus F. X. Mayer, Florence Courtois, Thomas Börner, Monique Liebers, Hagen Schlicke, Olaf Czarnecki, Bernhard Grimm, Stefan Hiekel, Lars Dietzel, Yan O. Zubo, Thomas Pfannschmidt, Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], InstitutfürMolekulare Biowissenschaften,Pflanzliche Zellphysiologie, Goethe-Universität Frankfurt am Main, Institute of Developmental Genetics [Neuherberg], Helmholtz-Zentrum München (HZM), Zentrum für Molekulare Biologie (ZMBH), Universität Heidelberg [Heidelberg], Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute of Plant Genetics and Crop Plant Research [Gatersleben] (IPK-Gatersleben), KWS SAAT SE & Co.KGaA, Humboldt-Universität zu Berlin, Dartmouth College [Hanover], German Research Center for Environmental Health (GmbH), Scientific Computing and Imaging Institute (SCI Institute), University of Utah, Grants from the Deutsche Forschungsgemeinschaft- Deutsche Forschungsgemeinschaft research group FOR 804., Physiologie cellulaire et végétale (LPCV), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Friedrich-Schiller-Universität Jena, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), KWS Saat AG, Humboldt Universität zu Berlin, Helmholtz Zentrum München = German Research Center for Environmental Health, Universität Heidelberg [Heidelberg] = Heidelberg University, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Humboldt University Of Berlin
Subjects: 0106 biological sciences, Time Factors, Light, Transcription, Genetic, Acclimatization, Arabidopsis, Plant Science, Regulatory Sequences, Nucleic Acid, 01 natural sciences, Gene Expression Regulation, Plant, Arabidopsis thaliana, Plastids, Photosynthesis, Early redox regulated genes, 0303 health sciences, Tetrapyrrole biosynthesis, Mitochondria, Cell biology, Chloroplast, Redox signals, Dibromothymoquinone, Biochemistry, Light acclimation, Oxidation-Reduction, Signal Transduction, Arabidopis thaliana, Nuclear gene, Biology, Bioenergetics, Genes, Plant, Redox, Nucleus, Electron Transport, 03 medical and health sciences, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, RNA, Messenger, Molecular Biology, 030304 developmental biology, Photosynthetic electron transport chain, Cell Nucleus, Mitochondrial electron transport, Plant, Chromatin Assembly and Disassembly, biology.organism_classification, Electron transport chain, Light intensity, Tetrapyrroles, Mutation, Gene expression, Reactive Oxygen Species, 010606 plant biology & botany
Abstract: Natural illumination conditions are highly variable and because of their sessile life style, plants are forced to acclimate to them at the cellular and molecular level. Changes in light intensity or quality induce changes in the reduction/oxidation (redox) state of the photosynthetic electron chain that acts as a trigger for compensatory acclimation responses comprising functional and structural adjustments of photosynthesis and metabolism. Such responses include redox-controlled changes in plant gene expression in the nucleus and organelles. Here we describe a strategy for the identification of early redox-regulated genes (ERGs) in the nucleus of the model organism Arabidopsis thaliana that respond significantly 30 or 60 min after the generation of a reduction signal in the photosynthetic electron transport chain. By comparing the response of wild-type plants with that of the acclimation mutant stn7, we could specifically identify ERGs. The results reveal a significant impact of chloroplast redox signals on distinct nuclear gene groups including genes for the mitochondrial electron transport chain, tetrapyrrole biosynthesis, carbohydrate metabolism, and signaling lipid synthesis. These expression profiles are clearly different from those observed in response to the reduction of photosynthetic electron transport by high light treatments. Thus, the ERGs identified are unique to redox imbalances in photosynthetic electron transport and were then used for analyzing potential redox-responsive cis-elements, trans-factors, and chromosomal regulatory hot spots. The data identify a novel redox-responsive element and indicate extensive redox control at transcriptional and chromosomal levels that point to an unprecedented impact of redox signals on epigenetic processes.
Published: 2015

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