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1. Structural and functional analysis of the Francisella lysine decarboxylase as a key actor in oxidative stress resistance

Author

Céline Brochier-Armanet, Yohann Couté, Pierre Simon Garcia, Angélique Fraudeau, Jan Felix, Patricia Renesto, Caroline Mas, Jérôme Nigou, Irina Gutsche, Karine Huard, Claire Siebert, Julia Novion Ducassou, Institut de biologie structurale (IBS - UMR 5075), 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 Grenoble Alpes (UGA), Translational microbial Evolution and Engineering (TIMC-TrEE), Translational Innovation in Medicine and Complexity / Recherche Translationnelle et Innovation en Médecine et Complexité - UMR 5525 (TIMC ), 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), Etude de la dynamique des protéomes (EDyP), BioSanté (UMR BioSanté), 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 (UGA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institut de pharmacologie et de biologie structurale (IPBS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-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), The platforms of the Grenoble Instruct center (ISBG, UMS 3518 CNRS-CEA-UJF-EMBL), ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010), ANR-10-INBS-0008,ProFI,Infrastructure Française de Protéomique(2010), 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), 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), 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), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Brochier-Armanet, Céline, Infrastructure Française pour la Biologie Structurale Intégrée - - FRISBI2010 - ANR-10-INBS-0005 - INBS - VALID, Grenoble Alliance for Integrated Structural Cell Biology - - GRAL2010 - ANR-10-LABX-0049 - LABX - VALID, Infrastructure Française de Protéomique - - ProFI2010 - ANR-10-INBS-0008 - INBS - VALID, and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Proteomics, 0301 basic medicine, DNA Repair, Carboxy-Lyases, Mutant, DETERMINANTS, SUSCEPTIBILITY, Virulence factor, Mice, Francisella tularensis, Tularemia, Cells, Cultured, Aromatic L-amino acid decarboxylase, [SDV.BIBS] Life Sciences [q-bio]/Quantitative Methods [q-bio.QM], Multidisciplinary, Virulence, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], biology, Lysine decarboxylase, Biological techniques, TULAREMIA, [SDV.BIBS]Life Sciences [q-bio]/Quantitative Methods [q-bio.QM], Cell biology, Phylogenetics, ACID, [SDV.BBM.GTP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], Francisella, Medicine, Microbiology techniques, [SDV.BBM.BS] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Science, 030106 microbiology, Proteomic analysis, Article, INTRACELLULAR SURVIVAL, 03 medical and health sciences, Bacterial Proteins, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], Escherichia coli, Animals, VIBRIO-VULNIFICUS, BIOSYNTHESIS, Amino Acid Sequence, Structure determination, Gene, Mass spectrometry, Macrophages, TULARENSIS PATHOGENICITY ISLAND, Biology and Life Sciences, biology.organism_classification, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, POLYAMINES, Oxidative Stress, 030104 developmental biology, VIRULENCE, [SDV.MP.BAC] Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Sequence Alignment
Abstract

Francisella tularensis is one of the most virulent pathogenic bacteria causing the acute human respiratory disease tularemia. While the mechanisms underlying F. tularensis pathogenesis are largely unknown, previous studies have shown that a F. novicida transposon mutant with insertions in a gene coding for a putative lysine decarboxylase was attenuated in mouse spleen, suggesting a possible role of its protein product as a virulence factor. Therefore, we set out to structurally and functionally characterize the F. novicida lysine decarboxylase, which we termed LdcF. Here, we investigate the genetic environment of ldcF as well as its evolutionary relationships with other basic AAT-fold amino acid decarboxylase superfamily members, known as key actors in bacterial adaptative stress response and polyamine biosynthesis. We determine the crystal structure of LdcF and compare it with the most thoroughly studied lysine decarboxylase, E. coli LdcI. We analyze the influence of ldcF deletion on bacterial growth under different stress conditions in dedicated growth media, as well as in infected macrophages, and demonstrate its involvement in oxidative stress resistance. Finally, our mass spectrometry-based quantitative proteomic analysis enables identification of 80 proteins with expression levels significantly affected by ldcF deletion, including several DNA repair proteins potentially involved in the diminished capacity of the F. novicida mutant to deal with oxidative stress. Taken together, we uncover an important role of LdcF in F. novicida survival in host cells through participation in oxidative stress response, thereby singling out this previously uncharacterized protein as a potential drug target.

Published
2021
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2. Production of acetoin from renewable resources under heterotrophic and mixotrophic conditions

Author

Carina Windhorst, Johannes Gescher, Yohann Couté, Julia Novion Ducassou, Daniel Härrer, Nicola Böhner, Etude de la dynamique des protéomes (EDyP), BioSanté (UMR BioSanté), 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 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), 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 (UGA)-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 (UGA), and Laboratoire Biosciences et bioingénierie pour la santé (BGE)

Subjects
0106 biological sciences, Proteomics, Environmental Engineering, Cupriavidus necator, [SDV]Life Sciences [q-bio], Bioengineering, Butyrate, 010501 environmental sciences, 01 natural sciences, 7. Clean energy, Polyhydroxybutyrate, chemistry.chemical_compound, 010608 biotechnology, Food science, Autotroph, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, chemistry.chemical_classification, Autotrophic Processes, biology, Renewable Energy, Sustainability and the Environment, Acetoin, Heterotrophic Processes, General Medicine, Dark fermentation, biology.organism_classification, chemistry, Propionate, Mixotroph
Abstract

This study aimed to reveal whether Cupriavidus necator H16 is suited for the production of acetoin based on the carboxylic acids acetate, butyrate and propionate under heterotrophic and mixotrophic conditions. The chosen production strain, lacking the polyhydroxybutyrate synthases phaC1 and phaC2, was revealed to be beneficiary for autotrophic acetoin production. Proteomic analysis of the strain determined that the deletions do indeed have a significant impact on pyruvate formation and its subsequent direction towards the introduced acetoin-synthesis pathway. Moreover, the strain was tested for its ability to use typical dark fermentation products under hetero- and mixotrophic conditions. Growth with butyrate and acetate led to low efficiencies, while 46.54% ±0.78 of the added propionate was converted into acetoin. Interestingly, mixotrophic conditions led to simultaneous consumption of acetate and butyrate with the gaseous substrates and lowered efficiency. In contrast, mixotrophic propionate consumption led to diauxic behavior and high carbon efficiency of 71.2% ±0.64.

Published
2021
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3. Extracellular Riboflavin Induces Anaerobic Biofilm Formation in Shewanella Oneidensis

Author

Julia Novion Ducassou, Johannes Gescher, Gunnar Sturm, Michael Wagner, Harald Horn, Yohann Couté, Katrin Sturm-Richter, Miriam Edel, Bruley, Christophe, Karlsruhe Institute of Technology (KIT), 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), Laboratoire de Biologie à Grande Échelle (BGE - UMR S1038), 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)-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), and Deutsche Verein des Gas- und Wasserfaches (DVGW)

Subjects
Life sciences, biology, [SDV]Life Sciences [q-bio], Flavin group, Microbiology, TP315-360, Current density, ddc:570, Extracellular, Shewanella oneidensis, chemistry.chemical_classification, Research, Biofilm, Biowissenschaften, Biologie [570], Biofilm matrix, food and beverages, Electron acceptor, biology.organism_classification, Fuel, Electron transport chain, 570: Biowissenschaften, Biologie, [SDV] Life Sciences [q-bio], Quorum sensing, chemistry, FOS: Biological sciences, Biophysics, TP248.13-248.65, Biotechnology
Abstract

Some microorganisms can respire with extracellular electron acceptors using an extended electron transport chain to the cell surface. These organisms apply flavin molecules as cofactors to facilitate one-electron transfer catalysed by the terminal reductases and as endogenous electron shuttles. In the model organism Shewanella oneidensis, riboflavin production and excretion triggers a specific biofilm formation response that is initiated at a specific threshold concentration, similar to canonical quorum sensing molecules. Riboflavin-mediated messaging is based on the overexpression of the gene encoding the putrescin decarboxylase speC which leads to posttranscriptional overproduction of proteins involved in biofilm formation. Using a model of growth-dependent riboflavin production under batch and biofilm growth conditions, the number of cells necessary to produce the threshold concentration per time was deduced. Furthermore, our results indicate that specific retention of riboflavin in the biofilm matrix leads to localized concentrations which by far exceed the necessary threshold value.ImportanceFerric iron is the fourth most abundant element of the earth crust. It occurs at neutral pH in the form insoluble iron minerals. The dissimilatory reduction of these minerals is an import part of global geological cycles and is catalyzed by microorganisms through extended respiratory chains to the cell surface. Shewanella oneidensis is one of the best understood model organisms for this kind of extracellular respiration. Flavins are important for the reduction of extracellular electron acceptors by S. oneidensis. since they have a function as (I) cofactors of the terminal reductases and (II) electron shuttles. In this study we reveal that flavin molecules are further employed as quorum sensing molecules. They are excreted by the organisms in a growth dependent manner and lead to anaerobic biofilm formation as a specific response at a certain threshold concentration. Although we know multiple examples of quorum sensing mechanisms, the use of riboflavin was so far not described and at least in S. oneidensis proceeds via a new regulatory routine that proceeds on the trancriptomic and posttranscriptomic level.

Published
2021
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4. Microglia modulate gliotransmission through the regulation of VAMP2 proteins in astrocytes

Author

Yohann Couté, Jérôme Honnorat, Fuyuko Takata-Tsuji, Christophe Place, Camille Philippot, Julia Novion Ducassou, Olivier Pascual, Naura Chounlamountri, Sarrah Ben Achour, Le-Duy Do, Institut NeuroMyoGène (INMG), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Etude de la dynamique des protéomes (EDyP), BioSanté (UMR BioSanté), Institut National de la Santé et de la Recherche Médicale (INSERM)-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)-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 (UGA), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), 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)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Hospices Civils de Lyon (HCL), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institut de biologie de l'ENS Paris (IBENS), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - 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 de Lyon-Université de Lyon-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)-École normale supérieure - Paris (ENS-PSL), and École normale supérieure de Lyon (ENS de Lyon)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
0301 basic medicine, Cell signaling, Vesicle-Associated Membrane Protein 2, Gliotransmitter, [SDV]Life Sciences [q-bio], Central nervous system, Neurotransmission, Biology, Synaptic Transmission, 03 medical and health sciences, Cellular and Molecular Neuroscience, Mice, 0302 clinical medicine, Adenosine Triphosphate, medicine, Animals, ComputingMilieux_MISCELLANEOUS, Microglia, VAMP2, Glutamate receptor, Cell biology, 030104 developmental biology, medicine.anatomical_structure, nervous system, Neurology, Astrocytes, SNARE Proteins, 030217 neurology & neurosurgery, Astrocyte
Abstract

Vesicular release is one of the release mechanisms of various signaling molecules. In neurons, the molecular machinery involved in vesicular release has been designed through evolution to trigger fast and synchronous release of neurotransmitters. Similar machinery with a slower kinetic and a slightly different molecular assembly allows astrocytes to release various transmitters such as adenosine triphosphate (ATP), glutamate, and D-serine. Astrocytes are important modulators of neurotransmission through gliotransmitter release. We recently demonstrated that microglia, another type of glia, release ATP to modulate synaptic transmission using astrocytes as intermediate. We now report that microglia regulate astrocytic gliotransmission through the regulation of SNARE proteins in astrocytes. Indeed, we found that gliotransmission triggered by P2Y1 agonist is impaired in slices from transgenic mice devoid of microglia. Using total internal reflection fluorescence imaging, we found that the vesicular release of gliotransmitter by astrocytes was different in cultures lacking microglia compared to vesicular release in astrocytes cocultured with microglia. Quantification of the kinetic of vesicular release indicates that the overall release appears to be faster in pure astrocyte cultures with more vesicles close to the membrane when compared to astrocytes cocultured with microglia. Finally, biochemical investigation of SNARE protein expression indicates an upregulation of VAMP2 in absence of microglia. Altogether, these results indicate that microglia seems to be involved in the regulation of an astrocytic phenotype compatible with proper gliotransmission. The mechanisms described in this study could be of importance for central nervous system diseases where microglia are activated.

Published
2021
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5. The PopN gate-keeper complex acts on the ATPase PscN to regulate the T3SS secretion switch from early to middle substrates in Pseudomonas aeruginosa

Author

Michel Ragno, Charles M. Stopford, Eric Faudry, Arne Rietsch, Alexandra Kraut, Caroline Perdu, Bakhos Jneid, Tuan Dung Ngo, Yohann Couté, Julia Novion Ducassou, Ina Attrée, Pathogenèse bactérienne et réponses cellulaires (PBRC), Centre National de la Recherche Scientifique (CNRS)-Biologie du Cancer et de l'Infection (BCI ), 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)-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 (UGA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Etude de la dynamique des protéomes (EDyP ), Laboratoire de Biologie à Grande Échelle (BGE - UMR S1038), 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 (UGA), Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, ANR PRP1.4 AVIESAN T3SS, Association Vaincre la Mucoviscidose, Association Grégory Lemarchal, ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010), ANR-15-CE11-0018,HemoPseudo,Pneumonie hémorragique à Pseudomonas aeruginosa : étude de nouvelles stratégies de virulence(2015), ANR-10-INBS-0008,ProFI,Infrastructure Française de Protéomique(2010), and ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017)

Subjects
Virulence Factors, ATPase, Microscale thermophoresis, Type three secretion system, Protein–protein interaction, Substrate Specificity, 03 medical and health sciences, 0302 clinical medicine, Bacterial Proteins, Structural Biology, Type III Secretion Systems, Bacteria pathogenesis, Secretion, Protein Interaction Maps, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], Molecular Biology, 030304 developmental biology, Adenosine Triphosphatases, 0303 health sciences, Protein-Protein interaction, biology, Mass spectrometry, Chemistry, Effector, Type 3 Secretion System, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Cell biology, Cytoplasm, Chaperone (protein), Pseudomonas aeruginosa, biology.protein, 030217 neurology & neurosurgery, Molecular Chaperones
Abstract

International audience; Pseudomonas aeruginosa is an opportunistic bacterium of which the main virulence factor is the Type III Secretion System. The ATPase of this machinery, PscN (SctN), is thought to be localized at the base of the secretion apparatus and to participate in the recognition, chaperone dissociation and unfolding of exported T3SS proteins. In this work, a protein-protein interaction ELISA revealed the interaction of PscN with a wide range of exported T3SS proteins including the needle, translocator, gate-keeper and effector. These interactions were further confirmed by Microscale Thermophoresis that also indicated a preferential interaction of PscN with secreted proteins or protein-chaperone complex rather than with chaperones alone, in line with the release of the chaperones in the bacterial cytoplasm after the dissociation from their exported proteins. Moreover, we suggest a new role of the gate-keeper complex and the ATPase in the regulation of early substrates recognition by the T3SS. This finding sheds a new light on the mechanism of secretion switching from early to middle substrates in P. aeruginosa .

Published
2020
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6. The PopN gate-keeper complex acts on the ATPase PscN to regulate the T3SS secretion switch from early to middle substrates inPseudomonas aeruginosa

Author

Tuan Dung Ngo, Bakhos Jneid, Alexandra Kraut, Charles M. Stopford, Eric Faudry, Michel Ragno, Arne Rietsch, Caroline Perdu, Ina Attrée, Yohann Couté, and Julia Novion Ducassou

Subjects
0303 health sciences, biology, 030306 microbiology, Microscale thermophoresis, Effector, Chemistry, ATPase, Type three secretion system, Cell biology, 03 medical and health sciences, Secretory protein, Cytoplasm, Chaperone (protein), biology.protein, Secretion, 030304 developmental biology
Abstract

Pseudomonas aeruginosais an opportunistic bacterium of which the main virulence factor is the Type III Secretion System. The ATPase of this machinery, PscN (SctN), is thought to be localized at the base of the secretion apparatus and to participate in the recognition, chaperone dissociation and unfolding of exported T3SS proteins. In this work, a protein-protein interaction ELISA revealed the interaction of PscN with a wide range of exported T3SS proteins including the needle, translocator, gate-keeper and effector. These interactions were further confirmed by Microscale Thermophoresis that also indicated a preferential interaction of PscN with secreted proteins or protein-chaperone complex rather than with chaperones alone, in line with the release of the chaperones in the bacterial cytoplasm after the dissociation from their exported proteins. Moreover, we suggest a new role of the gate-keeper complex and the ATPase in the regulation of early substrates recognition by the T3SS. This finding sheds a new light on the mechanism of secretion switching from early to middle substrates inP. aeruginosa.HighlightsT3SS substrates are secreted sequentially but information on the switches are missingInteraction of the T3SS ATPase with secreted proteins were investigated by different approachesMicroscale Thermophoresis revealed a lower affinity for chaperones alone compared to complexesThe Gate-keeper complex binds to the ATPase and increases its affinity for the needle complexA new role of the Gate-keeper complex is proposed, directly acting on the T3SS ATPase

Published
2020
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7. Developing Rhodobacter sphaeroides for cathodic biopolymer production

Author

Julia Novion Ducassou, Johannes Gescher, Ferdinand Schmid, Yohann Couté, Laboratoire Biosciences et bioingénierie pour la santé (BGE), Institut National de la Santé et de la Recherche Médicale (INSERM)-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), Etude de la dynamique des protéomes (EDyP), BioSanté (UMR BioSanté), 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 Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Laboratoire de Biologie à Grande Échelle (BGE - UMR S1038), and ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017)

Subjects
Proteomics, 0106 biological sciences, Environmental Engineering, [SDV]Life Sciences [q-bio], Kinetics, Bioengineering, Electron donor, Rhodobacter sphaeroides, 010501 environmental sciences, engineering.material, Electrochemistry, 01 natural sciences, Cathodic protection, chemistry.chemical_compound, Biopolymers, 010608 biotechnology, Electrodes, Waste Management and Disposal, 0105 earth and related environmental sciences, biology, Strain (chemistry), Renewable Energy, Sustainability and the Environment, Chemistry, Biofilm, General Medicine, biology.organism_classification, Chemical engineering, engineering, Biopolymer, Hydrogen
Abstract

Background Some microorganisms can respire with extracellular electron acceptors using an extended electron transport chain to the cell surface. This process can be applied in bioelectrochemical systems in which the organisms produce an electrical current by respiring with an anode as electron acceptor. These organisms apply flavin molecules as cofactors to facilitate one-electron transfer catalyzed by the terminal reductases and in some cases as endogenous electron shuttles. Results In the model organism Shewanella oneidensis , riboflavin production and excretion trigger a specific biofilm formation response that is initiated at a specific threshold concentration, similar to canonical quorum-sensing molecules. Riboflavin-mediated messaging is based on the overexpression of the gene encoding the putrescine decarboxylase speC which leads to posttranscriptional overproduction of proteins involved in biofilm formation. Using a model of growth-dependent riboflavin production under batch and biofilm growth conditions, the number of cells necessary to produce the threshold concentration per time was deduced. Furthermore, our results indicate that specific retention of riboflavin in the biofilm matrix leads to localized concentrations, which by far exceed the necessary threshold value. Conclusion This study describes a new quorum-sensing mechanism in S. oneidensis . Biofilm formation of S. oneidensis is induced by low concentrations of riboflavin resulting in an upregulation of the ornithine-decarboxylase speC . The results can be applied for the development of strains catalyzing increased current densities in bioelectrochemical systems.

Published
2021
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