CadC has a global translational effect during acid adaptation in Salmonella enterica serovar Typhimurium.
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.
Lee
Yong Heon
YH
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Kim
Bae Hoon
BH
Kim
Ji Hye
JH
Yoon
Won Suck
WS
Bang
Seong Ho
SH
Park
Yong Keun
YK
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*
D001426:Bacterial Proteins; C080050:CadC protein, Bacteria; D003470:Culture Media; C113724:OmpC protein; D018272:Porins; D020543:Proteome; D008239:Lysine