title: Exoproteomic analysis of the SecA2-dependent secretion in Listeria monocytogenes EGD-e.
abstract: As part of the Sec translocase, the accessory ATPase SecA2 is present in some pathogenic Gram-positive bacteria. In Listeria monocytogenes, deletion of secA2 results in filamentous cells that form rough colonies and have lower virulence. However, only a few proteins have been identified that are secreted by this pathway. This investigation aims to provide the first exoproteomic analysis of the SecA2-dependent secretion in L. monocytogenes EGD-e. By using media and temperatures relevant to bacterial physiology, we demonstrated that the rough colony and elongated bacterial cell morphotypes are highly dependent on growth conditions. Subsequently, comparative exoproteomic analyses of the ΔsecA2 versus wt strains were performed in chemically defined medium at 20°C and 37°C. Analyzing the proteomic data following the secretomics-based method, part of the proteins appeared routed towards the Sec pathway and exhibited an N-terminal signal peptide. For another significant part, they were primarily cytoplasmic proteins, thus lacking signal peptide and with no predictable secretion pathway. In total, 13 proteins were newly identified as secreted via SecA2, which were essentially associated with cell-wall metabolism, adhesion and/or biofilm formation. From this comparative exoproteomic analysis, new insights into the L. monocytogenes physiology are discussed in relation to its saprophytic and pathogenic lifestyle.
authors.affiliation: INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Renier
authors.affiliation: INRA, Plate-forme d'Exploration du Métabolisme, F-63122 Saint-Genès Champanelle, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Chambon
authors.affiliation: INRA, Plate-forme d'Exploration du Métabolisme, F-63122 Saint-Genès Champanelle, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Viala
authors.affiliation: INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Chagnot
authors.affiliation: INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France; INRA, Plate-forme d'Exploration du Métabolisme, F-63122 Saint-Genès Champanelle, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Hébraud
authors.affiliation: INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France. Electronic address: mickael.desvaux@clermont.inra.fr.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Desvaux
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D049109:Cell Proliferation; D002473:Cell Wall / Q000201:enzymology; D019295:Computational Biology; D003593:Cytoplasm / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005816:Genetic Complementation Test; D007525:Isoelectric Focusing; D008089:Listeria monocytogenes / Q000378:metabolism*; D021382:Protein Sorting Signals; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D021382:Protein Sorting Signals; D020543:Proteome; D000251:Adenosine Triphosphatases