title: Differential protein expression by Porphyromonas gingivalis in response to secreted epithelial cell components.
abstract: The human oral pathogen Porphyromonas gingivalis colonizes the gingival crevice and invades gingival epithelial cells. Multidimensional capillary high-performance liquid chromatography coupled with tandem mass spectrometry and two-dimensional gel electrophoresis were used to analyze the proteome of P. gingivalis as it adapts to a set of experimental conditions designed to reflect important features of an epithelial cell environment. 1014 proteins (46% of the total theoretical proteome) were identified in four independent analyses; 479 of these proteins showed evidence of differential expression after exposure of P. gingivalis to either conditioned epithelial cell growth medium or control conditions: i.e., they were only detected under one set of conditions. Moreover, 276 genes annotated as hypothetical were found to encode expressed proteins. Among the proteins up-regulated in the presence of epithelial cell components were a homolog of the internalin proteins of Listeria monocytogenes and subunits of the ATP-dependent Clp protease complex. Insertional inactivation of clpP, encoding the Clp proteolytic subunit, resulted in approximately a 50% reduction in invasion of P. gingivalis. These results suggest that adaptation to an epithelial cell environment induces a major shift in the expressed proteome of the organism. Furthermore, ClpP, that is up-regulated in this environment, is required for optimal invasive activity of P. gingivalis.
authors.affiliation: Department of Microbiology, University of Wahington, Seattle, WA 98195, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Tiansong
authors.initials: T
authors.lastname: Wang
authors.forename: Weibin
authors.initials: W
authors.lastname: Chen
authors.forename: Ozlem
authors.initials: O
authors.lastname: Yilmaz
authors.forename: Yoonsuk
authors.initials: Y
authors.lastname: Park
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Jung
authors.forename: Murray
authors.initials: M
authors.lastname: Hackett
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lamont
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D015180:Electrophoresis, Gel, Two-Dimensional; D049071:Endopeptidase Clp / Q000096:biosynthesis / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology; D020869:Gene Expression Profiling; D005881:Gingiva / Q000378:metabolism* / Q000382:microbiology; D006801:Humans; D013058:Mass Spectrometry; D009154:Mutation; D016966:Porphyromonas gingivalis / Q000378:metabolism* / Q000472:pathogenicity; D040081:Protein Array Analysis; D020543:Proteome / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; D020543:Proteome; D049071:Endopeptidase Clp