title: Dissecting the Escherichia coli periplasmic chaperone network using differential proteomics.
abstract: β-Barrel proteins, or outer membrane proteins (OMPs), perform many essential functions in Gram-negative bacteria, but questions remain about the mechanism by which they are assembled into the outer membrane (OM). In Escherichia coli, β-barrels are escorted across the periplasm by chaperones, most notably SurA and Skp. However, the contributions of these two chaperones to the assembly of the OM proteome remained unclear. We used differential proteomics to determine how the elimination of Skp and SurA affects the assembly of many OMPs. We have shown that removal of Skp has no impact on the levels of the 63 identified OM proteins. However, depletion of SurA in the skp strain has a marked impact on the OM proteome, diminishing the levels of almost all β-barrel proteins. Our results are consistent with a model in which SurA plays a primary chaperone role in E. coli. Furthermore, they suggest that while no OMPs prefer the Skp chaperone pathway in wild-type cells, most can use Skp efficiently when SurA is absent. Our data, which provide a unique glimpse into the protein content of the nonviable surA skp mutant, clarify the roles of the periplasmic chaperones in E. coli.
authors.affiliation: WELBIO (Walloon excellence in life sciences and biotechnology).|de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium.
authors.forename: Katleen
authors.initials: K
authors.lastname: Denoncin
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, 9 USA.
authors.forename: Jaclyn
authors.initials: J
authors.lastname: Schwalm
authors.affiliation: de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium.
authors.forename: Didier
authors.initials: D
authors.lastname: Vertommen
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, 9 USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Silhavy
authors.affiliation: WELBIO (Walloon excellence in life sciences and biotechnology).|de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Collet
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D055786:Gene Knockout Techniques; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D019897:Periplasm / Q000378:metabolism; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics / Q000379:methods
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; D020543:Proteome; C072721:Skp protein, E coli; C490900:SurA protein, E coli; D019696:Peptidylprolyl Isomerase