title: CadC has a global translational effect during acid adaptation in Salmonella enterica serovar Typhimurium.
abstract: In Salmonella enterica serovar Typhimurium, the membrane-localized CadC is a transcriptional activator of the cadBA operon, which contributes to the acid tolerance response. Unlike in Escherichia coli, in which transcription of cadC is constitutive, in S. enterica serovar Typhimurium cadC expression is induced by low pH and lysine. Inactivation of cadC suppresses the acid-sensitive phenotype of a cadA mutation, suggesting the existence of other CadC-dependent genes in addition to the cadBA operon. Using a proteomic approach, we identified 8 of the putative CadC-induced proteins and 15 of the putative CadC-repressed proteins. The former include porin proteins OmpC and OmpF. The latter include proteins involved in glycolysis, energy production, and stress tolerance. To better understand the altered levels of OmpC and OmpF, we compared expression of ompR in S. enterica serovar Typhimurium wild-type and cadC mutant strains and determined that CadC exerted a negative influence on ompR transcription. Taken together, our findings strongly suggest that CadC may be a global regulator involved in the OmpR regulatory system during acid adaptation.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Yong Heon
authors.initials: YH
authors.lastname: Lee
authors.forename: Bae Hoon
authors.initials: BH
authors.lastname: Kim
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Won Suck
authors.initials: WS
authors.lastname: Yoon
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Bang
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Park
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000494:pharmacology; D009154:Mutation; D018272:Porins / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D020543:Proteome; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C080050:CadC protein, Bacteria; D003470:Culture Media; C113724:OmpC protein; D018272:Porins; D020543:Proteome; D008239:Lysine