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21 results on '"Mavrakis, Manos"'

1. Human septins organize as octamer-based filaments and mediate actin-membrane anchoring in cells

Author

Martins, Carla Silva, Taveneau, Cyntia, Castro-Linares, Gerard, Baibakov, Mikhail, Buzhinsky, Nicolas, Eroles, Mar, Milanović, Violeta, Omi, Shizue, Pedelacq, Jean-Denis, Iv, Francois, Bouillard, Léa, Llewellyn, Alexander, Gomes, Maxime, Belhabib, Mayssa, Kuzmić, Mira, Verdier-Pinard, Pascal, Lee, Stacey, Badache, Ali, Kumar, Sanjay, Chandre, Cristel, Brasselet, Sophie, Rico, Felix, Rossier, Olivier, Koenderink, Gijsje H, Wenger, Jerome, Cabantous, Stéphanie, and Mavrakis, Manos

Subjects
Biochemistry and Cell Biology, Biological Sciences, Bioengineering, Nanotechnology, 1.1 Normal biological development and functioning, Underpinning research, Generic health relevance, Humans, Actins, Cell Membrane, Cytoskeleton, Microscopy, Septins, Medical and Health Sciences, Developmental Biology, Biological sciences, Biomedical and clinical sciences
Abstract

Septins are cytoskeletal proteins conserved from algae and protists to mammals. A unique feature of septins is their presence as heteromeric complexes that polymerize into filaments in solution and on lipid membranes. Although animal septins associate extensively with actin-based structures in cells, whether septins organize as filaments in cells and if septin organization impacts septin function is not known. Customizing a tripartite split-GFP complementation assay, we show that all septins decorating actin stress fibers are octamer-containing filaments. Depleting octamers or preventing septins from polymerizing leads to a loss of stress fibers and reduced cell stiffness. Super-resolution microscopy revealed septin fibers with widths compatible with their organization as paired septin filaments. Nanometer-resolved distance measurements and single-protein tracking further showed that septin filaments are membrane bound and largely immobilized. Finally, reconstitution assays showed that septin filaments mediate actin-membrane anchoring. We propose that septin organization as octamer-based filaments is essential for septin function in anchoring and stabilizing actin filaments at the plasma membrane.

Published
2023

5. Genetically encoded reporters of actin filament organization in living cells and tissues

Author

Silva Martins, Carla, primary, Iv, Francois, additional, Kumar Suman, Shashi, additional, Panagiotou, Thomas C., additional, Sidor, Clara, additional, Ruso-Lopez, Maria, additional, Plancke, Camille N., additional, Omi, Shizue, additional, Gomes, Maxime, additional, Llewellyn, Alexander, additional, Bandi, Sourish Reddy, additional, Ramond, Laurie, additional, Arbizzani, Federica, additional, Rimoli, Caio Vaz, additional, Schnorrer, Frank, additional, Robin, Francois, additional, Wilde, Andrew, additional, LeGoff, Loic, additional, Pedelacq, Jean-Denis, additional, Cabantous, Stephanie, additional, Rincon, Sergio A., additional, Chandre, Cristel, additional, Brasselet, Sophie, additional, and Mavrakis, Manos, additional

Published
2024
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6. Septin-microtubule association via a motif unique to isoform 1 of septin 9 tunes stress fibers.

Author

Kuzmić, Mira, Castro Linares, Gerard, Leischner Fialová, Jindřiška, Iv, François, Salaün, Daniele, Llewellyn, Alex, Gomes, Maxime, Belhabib, Mayssa, Yuxiang Liu, Keisuke Asano, Rodrigues, Magda, Isnardon, Daniel, Tachibana, Taro, Koenderink, Gijsje H., Badache, Ali, Mavrakis, Manos, and Verdier-Pinard, Pascal

Subjects
MICROTUBULES, BRACHIAL plexus neuropathies, MOLECULAR pathology, G proteins, SEPTINS, MICROTUBULE-associated proteins, FIBERS
Abstract

Septins, a family of GTP-binding proteins that assemble into higher order structures, interface with the membrane, actin filaments and microtubules, and are thus important regulators of cytoarchitecture. Septin 9 (SEPT9), which is frequently overexpressed in tumors and mutated in hereditary neuralgic amyotrophy (HNA), mediates the binding of septins to microtubules, but the molecular determinants of this interaction remained uncertain. We demonstrate that a short microtubule-associated protein (MAP)-like motif unique to SEPT9 isoform 1 (SEPT9_i1) drives septin octamer-microtubule interaction in cells and in vitro reconstitutions. Septin-microtubule association requires polymerizable septin octamers harboring SEPT9_i1. Although outside of the MAP-like motif, HNA mutations abrogate this association, identifying a putative regulatory domain. Removal of this domain from SEPT9_i1 sequesters septins on microtubules, promotes microtubule stability and alters actomyosin fiber distribution and tension. Thus, we identify key molecular determinants and potential regulatory roles of septin-microtubule interaction, paving the way to deciphering themechanisms underlying septin-associated pathologies. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Supplementary Video 2 from Protein Kinase A Effects of an Expressed PRKAR1A Mutation Associated with Aggressive Tumors

Author

Meoli, Elise, primary, Bossis, Ioannis, primary, Cazabat, Laure, primary, Mavrakis, Manos, primary, Horvath, Anelia, primary, Stergiopoulos, Sotiris, primary, Shiferaw, Miriam L., primary, Fumey, Glawdys, primary, Perlemoine, Karine, primary, Muchow, Michael, primary, Robinson-White, Audrey, primary, Weinberg, Frank, primary, Nesterova, Maria, primary, Patronas, Yianna, primary, Groussin, Lionel, primary, Bertherat, Jérôme, primary, and Stratakis, Constantine A., primary

Published
2023
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8. Data from Protein Kinase A Effects of an Expressed PRKAR1A Mutation Associated with Aggressive Tumors

Author

Meoli, Elise, primary, Bossis, Ioannis, primary, Cazabat, Laure, primary, Mavrakis, Manos, primary, Horvath, Anelia, primary, Stergiopoulos, Sotiris, primary, Shiferaw, Miriam L., primary, Fumey, Glawdys, primary, Perlemoine, Karine, primary, Muchow, Michael, primary, Robinson-White, Audrey, primary, Weinberg, Frank, primary, Nesterova, Maria, primary, Patronas, Yianna, primary, Groussin, Lionel, primary, Bertherat, Jérôme, primary, and Stratakis, Constantine A., primary

Published
2023
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9. sSupplementary Video 3 from Protein Kinase A Effects of an Expressed PRKAR1A Mutation Associated with Aggressive Tumors

Author

Meoli, Elise, primary, Bossis, Ioannis, primary, Cazabat, Laure, primary, Mavrakis, Manos, primary, Horvath, Anelia, primary, Stergiopoulos, Sotiris, primary, Shiferaw, Miriam L., primary, Fumey, Glawdys, primary, Perlemoine, Karine, primary, Muchow, Michael, primary, Robinson-White, Audrey, primary, Weinberg, Frank, primary, Nesterova, Maria, primary, Patronas, Yianna, primary, Groussin, Lionel, primary, Bertherat, Jérôme, primary, and Stratakis, Constantine A., primary

Published
2023
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10. Supplementary Video 1 from Protein Kinase A Effects of an Expressed PRKAR1A Mutation Associated with Aggressive Tumors

Author

Meoli, Elise, primary, Bossis, Ioannis, primary, Cazabat, Laure, primary, Mavrakis, Manos, primary, Horvath, Anelia, primary, Stergiopoulos, Sotiris, primary, Shiferaw, Miriam L., primary, Fumey, Glawdys, primary, Perlemoine, Karine, primary, Muchow, Michael, primary, Robinson-White, Audrey, primary, Weinberg, Frank, primary, Nesterova, Maria, primary, Patronas, Yianna, primary, Groussin, Lionel, primary, Bertherat, Jérôme, primary, and Stratakis, Constantine A., primary

Published
2023
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11. Human septins organize as octamer-based filaments and mediate actin-membrane anchoring in cells

Author

Martins, Carla Silva, primary, Taveneau, Cyntia, additional, Castro-Linares, Gerard, additional, Baibakov, Mikhail, additional, Buzhinsky, Nicolas, additional, Eroles, Mar, additional, Milanović, Violeta, additional, Omi, Shizue, additional, Pedelacq, Jean-Denis, additional, Iv, Francois, additional, Bouillard, Léa, additional, Llewellyn, Alexander, additional, Gomes, Maxime, additional, Belhabib, Mayssa, additional, Kuzmić, Mira, additional, Verdier-Pinard, Pascal, additional, Lee, Stacey, additional, Badache, Ali, additional, Kumar, Sanjay, additional, Chandre, Cristel, additional, Brasselet, Sophie, additional, Rico, Felix, additional, Rossier, Olivier, additional, Koenderink, Gijsje H., additional, Wenger, Jerome, additional, Cabantous, Stéphanie, additional, and Mavrakis, Manos, additional

Published
2022
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12. Septin-microtubule association requires a MAP-like motif unique to Sept9 isoform 1 embedded into septin octamers

Author

Kuzmić, Mira, Castro Linares, Gerard, Leischner Fialová, Jindřiška, Iv, Francois, Salaün, Danièle, Llewellyn, Alex, Gomes, Maxime, Belhabib, Mayssa, Liu, Yuxiang, Asano, Keisuke, Rodrigues, Magda, Isnardon, Daniel, Tachibana, Taro, Koenderink, Gijsje, Badache, Ali, Mavrakis, Manos, Verdier-Pinard, Pascal, Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Delft University of Technology (TU Delft), Kavli Institute of Nanosciences [Delft] (KI-NANO), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), MOSAIC (MOSAIC), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), University of Shanghai [Shanghai], Osaka City University (OCU), ANR-17-CE13-0014,SEPTIMORF,Rôle des septines dans la morphogenèse des cellules animales(2017), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Mavrakis, Manos, and Rôle des septines dans la morphogenèse des cellules animales - - SEPTIMORF2017 - ANR-17-CE13-0014 - AAPG2017 - VALID

Subjects
[SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, fungi, [SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.BC.BC] Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], [SDV.BBM.BP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, [SDV.BDD.MOR]Life Sciences [q-bio]/Development Biology/Morphogenesis, macromolecular substances, [SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], [SDV.BC.IC] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], biological phenomena, cell phenomena, and immunity, [SDV.BDD.MOR] Life Sciences [q-bio]/Development Biology/Morphogenesis
Abstract

International audience; Septins, a family of GTP-binding proteins assembling into higher order structures, interface with the membrane, actin filaments and microtubules, which positions them as important regulators of cytoarchitecture. Septin 9 (Sept9), which is frequently overexpressed in tumors and mutated in hereditary neuralgic amyotrophy (HNA), mediates the binding of septins to microtubules, but the molecular determinants of this interaction remained uncertain. We demonstrate that a short MAP-like motif unique to Sept9 isoform 1 (Sept9_i1) drives septin octamer-microtubule interaction in cells and in vitro reconstitutions. Septin-microtubule association requires polymerizable septin octamers harboring Sept9_i1. Although outside of the MAP-like motif, HNA mutations abrogates this association, identifying a putative regulatory domain. Removal of this domain from Sept9_i1 sequesters septins on microtubules, promotes microtubule stability and alters actomyosin fiber distribution and tension. Thus, we identify key molecular determinants and potential regulatory roles of septin-microtubule interaction, paving the way to deciphering the mechanisms underlying septin associated pathologies.

Published
2022
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13. Bottom-Up In Vitro Methods to Assay the Ultrastructural Organization, Membrane Reshaping, and Curvature Sensitivity Behavior of Septins

Author

Chauvin, Brieuc, primary, Nakazawa, Koyomi, primary, Beber, Alexandre, primary, Di Cicco, Aurélie, primary, Hajj, Bassam, primary, Iv, François, primary, Mavrakis, Manos, primary, Koenderink, Gijsje H., primary, Cabral, João T., primary, Trichet, Michaël, primary, Mangenot, Stéphanie, primary, and Bertin, Aurélie, primary

Published
2022
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15. Purification and Quality Control of Recombinant Septin Complexes for Cell-Free Reconstitution

Author

Castro Linares, G. (author), den Haan, J.C.A. (author), Iv, Francois (author), Martins, Carla Silva (author), Bertin, Aurélie (author), Mavrakis, Manos (author), Koenderink, G.H. (author), Castro Linares, G. (author), den Haan, J.C.A. (author), Iv, Francois (author), Martins, Carla Silva (author), Bertin, Aurélie (author), Mavrakis, Manos (author), and Koenderink, G.H. (author)

Abstract

Septins are a family of conserved eukaryotic GTP-binding proteins that can form cytoskeletal filaments and higher-order structures from hetero-oligomeric complexes. They interact with other cytoskeletal components and the cell membrane to participate in important cellular functions such as migration and cell division. Due to the complexity of septins' many interactions, the large number of septin genes (13 in humans), and the ability of septins to form hetero-oligomeric complexes with different subunit compositions, cell-free reconstitution is a vital strategy to understand the basics of septin biology. The present paper first describes a method to purify recombinant septins in their hetero-oligomeric form using a two-step affinity chromatography approach. Then, the process of quality control used to check for the purity and integrity of the septin complexes is detailed. This process combines native and denaturing gel electrophoresis, negative stain electron microscopy, and interferometric scattering microscopy. Finally, a description of the process to check for the polymerization ability of septin complexes using negative stain electron microscopy and fluorescent microscopy is given. This demonstrates that it is possible to produce high-quality human septin hexamers and octamers containing different isoforms of septin_9, as well as Drosophila septin hexamers., uilding a Synthetic Cell' Gravitation grant (024.003.019) and from the Agence Nationale pour la Recherche (ANR grants ANR-17-CE13-0014: “SEPTIMORF”; ANR-13-JSV8-0002-01: “SEPTIME”; and ANR-20-CE11-0014-01: “SEPTSCORT”). Publisher Copyright: © 2022 JoVE., BN/Gijsje Koenderink Lab

Published
2022
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16. Bottom-Up In Vitro Methods to Assay the Ultrastructural Organization, Membrane Reshaping, and Curvature Sensitivity Behavior of Septins

Author

Chauvin, Brieuc (author), Nakazawa, Koyomi (author), Beber, Alexandre (author), Di Cicco, Aurélie (author), Hajj, Bassam (author), Iv, François (author), Mavrakis, Manos (author), Koenderink, G.H. (author), Cabral, João T. (author), Chauvin, Brieuc (author), Nakazawa, Koyomi (author), Beber, Alexandre (author), Di Cicco, Aurélie (author), Hajj, Bassam (author), Iv, François (author), Mavrakis, Manos (author), Koenderink, G.H. (author), and Cabral, João T. (author)

Abstract

Membrane remodeling occurs constantly at the plasma membrane and within cellular organelles. To fully dissect the role of the environment (ionic conditions, protein and lipid compositions, membrane curvature) and the different partners associated with specific membrane reshaping processes, we undertake in vitro bottom-up approaches. In recent years, there has been keen interest in revealing the role of septin proteins associated with major diseases. Septins are essential and ubiquitous cytoskeletal proteins that interact with the plasma membrane. They are implicated in cell division, cell motility, neuro-morphogenesis, and spermiogenesis, among other functions. It is, therefore, important to understand how septins interact and organize at membranes to subsequently induce membrane deformations and how they can be sensitive to specific membrane curvatures. This article aims to decipher the interplay between the ultra-structure of septins at a molecular level and the membrane remodeling occurring at a micron scale. To this end, budding yeast, and mammalian septin complexes were recombinantly expressed and purified. A combination of in vitro assays was then used to analyze the self-assembly of septins at the membrane. Supported lipid bilayers (SLBs), giant unilamellar vesicles (GUVs), large unilamellar vesicles (LUVs), and wavy substrates were used to study the interplay between septin self-assembly, membrane reshaping, and membrane curvature., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., BN/Gijsje Koenderink Lab

Published
2022
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17. Human septins in cells organize as octamer-based filaments mediating actin-membrane anchoring

Author

Martins, Carla Silva, primary, Taveneau, Cyntia, additional, Castro-Linares, Gerard, additional, Baibakov, Mikhail, additional, Buzhinsky, Nicolas, additional, Eroles, Mar, additional, Milanović, Violeta, additional, Iv, Francois, additional, Bouillard, Léa, additional, Llewellyn, Alex, additional, Gomes, Maxime, additional, Belhabib, Mayssa, additional, Kuzmić, Mira, additional, Verdier-Pinard, Pascal, additional, Lee, Stacey, additional, Badache, Ali, additional, Kumar, Sanjay, additional, Chandre, Cristel, additional, Brasselet, Sophie, additional, Rico, Felix, additional, Rossier, Olivier, additional, Koenderink, Gijsje H., additional, Wenger, Jerome, additional, Cabantous, Stéphanie, additional, and Mavrakis, Manos, additional

Published
2022
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18. Septin-microtubule association via a motif unique to isoform 1 of septin 9 tunes stress fibers

Author

Kuzmić, Mira, primary, Castro Linares, Gerard, additional, Leischner Fialová, Jindřiška, additional, Iv, François, additional, Salaün, Danièle, additional, Llewellyn, Alex, additional, Gomes, Maxime, additional, Belhabib, Mayssa, additional, Liu, Yuxiang, additional, Asano, Keisuke, additional, Rodrigues, Magda, additional, Isnardon, Daniel, additional, Tachibana, Taro, additional, Koenderink, Gijsje H., additional, Badache, Ali, additional, Mavrakis, Manos, additional, and Verdier-Pinard, Pascal, additional

Published
2022
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19. Septin-microtubule association via a motif unique to isoform 1 of septin 9 tunes stress fibers.

Author

Kuzmić, Mira, Linares, Gerard Castro, Fialovÿ, Jindřiška Leischner, Iv, François, Salaün, Danièle, Llewellyn, Alex, Gomes, Maxime, Belhabib, Mayssa, Yuxiang Liu, Asano, Keisuke, Rodrigues, Magda, Isnardon, Daniel, Tachibana, Taro, Koenderink, Gijsje H., Badache, Ali, Mavrakis, Manos, and Verdier-Pinard, Pascal

Subjects
MICROTUBULES, G proteins, MOLECULAR interactions, SEPTINS, BRACHIAL plexus neuropathies, MICROTUBULE-associated proteins, CYTOSKELETON
Abstract

Septins, a family of GTP-binding proteins that assemble into higher order structures, interface with the membrane, actin filaments and microtubules, and are thus important regulators of cytoarchitecture. Septin 9 (SEPT9), which is frequently overexpressed in tumors and mutated in hereditary neuralgic amyotrophy (HNA), mediates the binding of septins to microtubules, but the molecular determinants of this interaction remained uncertain. We demonstrate that a short microtubule-associated protein (MAP)-like motif unique to SEPT9 isoform 1 (SEPT9_i1) drives septin octamer-microtubule interaction in cells and in vitro reconstitutions. Septin-microtubule association requires polymerizable septin octamers harboring SEPT9_i1. Although outside of the MAP-like motif, HNA mutations abrogate this association, identifying a putative regulatory domain. Removal of this domain from SEPT9_i1 sequesters septins on microtubules, promotes microtubule stability and alters actomyosin fiber distribution and tension. Thus, we identify key molecular determinants and potential regulatory roles of septin-microtubule interaction, paving the way to deciphering themechanisms underlying septin-associated pathologies. [ABSTRACT FROM AUTHOR]

Published
2023
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20. Human Septins Organize as Octamer-Based Filaments and Mediate Actin-Membrane Anchoring in Cells

Author

Carla Silva Martins, Cyntia Taveneau, Gerard Castro-Linares, Mikhail Baibakov, Nicolas Buzhinsky, Mar Eroles, Violeta Milanović, Shizue Omi, Jean-Denis Pedelacq, Francois Iv, Léa Bouillard, Alexander Llewellyn, Maxime Gomes, Mayssa Belhabib, Mira Kuzmić, Pascal Verdier-Pinard, Stacey Lee, Ali Badache, Sanjay Kumar, Cristel Chandre, Sophie Brasselet, Felix Rico, Olivier Rossier, Gijsje H. Koenderink, Jerome Wenger, Stéphanie Cabantous, Manos Mavrakis, Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), MOSAIC (MOSAIC), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Monash University [Clayton], Delft University of Technology (TU Delft), Adhésion et Inflammation (LAI), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Interdisciplinary Institute for Neuroscience [Bordeaux] (IINS), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Institut de pharmacologie et de biologie structurale (IPBS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Bioengineering [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut de Mathématiques de Marseille (I2M), Centre de Recherches en Cancérologie de Toulouse (CRCT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), This work was supported in part by the National Institutes of Health (R01GM122375 to S.K.). Confocal microscopy with the Zeiss LSM710 microscope and SIM with the Zeiss Elyra PS.1 microscope was performed at the UC Berkeley Biological Imaging Facility, which was supported in part by the National Institutes of Health S10 program under award numbers 1S10RR026866-01 and 1S10OD018136-01. G.C.L. and G.H.K. gratefully acknowledge financial support by the Netherlands Organization for Scientific Research (NWO/OCW) through the ‘BaSyC—Building a Synthetic Cell’ Gravitation grant (024.003.019)., ANR-17-CE13-0014,SEPTIMORF,Rôle des septines dans la morphogenèse des cellules animales(2017), ANR-20-CE42-0003,3DPolariSR,Microscopie super résolue polarisée pour l'imagerie conformationnelle(2020), ANR-17-CE09-0026,AntennaFRET,Nanoantennes optiques pour exalter le transfert d'énergie de Förster : applications aux protéines(2017), ANR-10-INBS-0004,France-BioImaging,Développment d'une infrastructure française distribuée coordonnée(2010), ANR-10-LABX-0043,BRAIN,Bordeaux Region Aquitaine Initiative for Neuroscience(2010), European Project: 723241,COG, European Project: 772257,MechaDynA, European Project: 812772,Phys2BioMed, Mavrakis, Manos, Rôle des septines dans la morphogenèse des cellules animales - - SEPTIMORF2017 - ANR-17-CE13-0014 - AAPG2017 - VALID, Microscopie super résolue polarisée pour l'imagerie conformationnelle - - 3DPolariSR2020 - ANR-20-CE42-0003 - AAPG2020 - VALID, Nanoantennes optiques pour exalter le transfert d'énergie de Förster : applications aux protéines - - AntennaFRET2017 - ANR-17-CE09-0026 - AAPG2017 - VALID, Développment d'une infrastructure française distribuée coordonnée - - France-BioImaging2010 - ANR-10-INBS-0004 - INBS - VALID, Bordeaux Region Aquitaine Initiative for Neuroscience - - BRAIN2010 - ANR-10-LABX-0043 - LABX - VALID, Boosting tryptophan fluorescence with optical nanoantennas to watch label-free protein dynamics with single molecule resolution at high concentration - COG - 723241 - INCOMING, Multi-scale mechanics of dynamic leukocyte adhesion - MechaDynA - 772257 - INCOMING, European Union’s Horizon 2020 research and innovation programme - Phys2BioMed - 812772 - INCOMING, Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Mammals, Microscopy, 1.1 Normal biological development and functioning, Cell Membrane, [SDV.BBM.BP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Bioengineering, [SDV.BDD.MOR]Life Sciences [q-bio]/Development Biology/Morphogenesis, Cell Biology, [SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], Biological Sciences, [SDV.BC.IC] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], Medical and Health Sciences, Actins, [SDV.BDD.MOR] Life Sciences [q-bio]/Development Biology/Morphogenesis, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Underpinning research, [SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.BC.BC] Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], Nanotechnology, Animals, Humans, Generic health relevance, Septins, Cytoskeleton, Developmental Biology
Abstract

International audience; Septins are cytoskeletal proteins conserved from algae and protists to mammals. A unique feature of septins is their presence as heteromeric complexes that polymerize into filaments in solution and on lipid membranes. Although animal septins associate extensively with actin-based structures in cells, whether septins organize as filaments and if septin organization impacts septin function is not known. Customizing a tripartite split-GFP complementation assay, we show that all septins decorating actin stress fibers are octamer-containing filaments. Depleting octamers or preventing septins from polymerizing leads to a loss of stress fibers and reduced cell stiffness. Super-resolution microscopy revealed septin fibers with widths compatible with their organization as paired septin filaments. Nanometer-resolved distance measurements and single-protein tracking further showed that septin filaments are membrane-bound and largely immobilized. Finally, reconstitution assays on supported lipid bilayers showed that septin filaments mediate actin-membrane anchoring. We propose that septin organization as octamer-based filaments is essential for septin function in anchoring and stabilizing actin filaments at the plasma membrane.

Published
2023
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21. Animal septins contain functional transmembrane domains.

Author

Perry JA, Werner ME, Omi S, Heck BW, Maddox PS, Mavrakis M, and Maddox AS

Abstract

Septins, a conserved family of filament-forming proteins, contribute to eukaryotic cell division, polarity, and membrane trafficking. Septins scaffold other proteins to cellular membranes, but it is unknown how septins associate with membranes. We identified and characterized an isoform of Caenorhabditis elegans septin UNC-61 that was predicted to contain a transmembrane domain (TMD). The TMD isoform is expressed in a subset of tissues where the known septins were known to act, and TMD function was required for tissue integrity of the egg-laying apparatus. We found TMD-containing septins across opisthokont phylogeny and demonstrated that the TMD-containing sequence of a primate TMD-septin is sufficient for localization to cellular membranes. Together, our findings reveal a novel mechanism of septin-membrane association with profound implications for septin dynamics and regulation., Competing Interests: Competing interests: The authors have declared no competing interests.

Published
2024
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