title: Proteomics of protein secretion by Bacillus subtilis: separating the "secrets" of the secretome.
abstract: Secretory proteins perform a variety of important "remote-control" functions for bacterial survival in the environment. The availability of complete genome sequences has allowed us to make predictions about the composition of bacterial machinery for protein secretion as well as the extracellular complement of bacterial proteomes. Recently, the power of proteomics was successfully employed to evaluate genome-based models of these so-called secretomes. Progress in this field is well illustrated by the proteomic analysis of protein secretion by the gram-positive bacterium Bacillus subtilis, for which approximately 90 extracellular proteins were identified. Analysis of these proteins disclosed various "secrets of the secretome," such as the residence of cytoplasmic and predicted cell envelope proteins in the extracellular proteome. This showed that genome-based predictions reflect only approximately 50% of the actual composition of the extracellular proteome of B. subtilis. Importantly, proteomics allowed the first verification of the impact of individual secretion machinery components on the total flow of proteins from the cytoplasm to the extracellular environment. In conclusion, proteomics has yielded a variety of novel leads for the analysis of protein traffic in B. subtilis and other gram-positive bacteria. Ultimately, such leads will serve to increase our understanding of virulence factor biogenesis in gram-positive pathogens, which is likely to be of high medical relevance.
authors.affiliation: Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Kerklaan 30, 9751 NN Haren, The Netherlands.
authors.forename: Harold
authors.initials: H
authors.lastname: Tjalsma
authors.forename: Haike
authors.initials: H
authors.lastname: Antelmann
authors.forename: Jan D H
authors.initials: JD
authors.lastname: Jongbloed
authors.forename: Peter G
authors.initials: PG
authors.lastname: Braun
authors.forename: Elise
authors.initials: E
authors.lastname: Darmon
authors.forename: Ronald
authors.initials: R
authors.lastname: Dorenbos
authors.forename: Jean-Yves F
authors.initials: JY
authors.lastname: Dubois
authors.forename: Helga
authors.initials: H
authors.lastname: Westers
authors.forename: Geeske
authors.initials: G
authors.lastname: Zanen
authors.forename: Wim J
authors.initials: WJ
authors.lastname: Quax
authors.forename: Oscar P
authors.initials: OP
authors.lastname: Kuipers
authors.forename: Sierd
authors.initials: S
authors.lastname: Bron
authors.forename: Michael
authors.initials: M
authors.lastname: Hecker
authors.forename: Jan Maarten
authors.initials: JM
authors.lastname: van Dijl
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals / Q000235:genetics; D021381:Protein Transport; D040901:Proteomics / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D033903:Periplasmic Proteins; D021382:Protein Sorting Signals