The RstB sensor acts on the PhoQ sensor to control expression of PhoP-regulated genes.
The PhoP response regulator and PhoQ sensor, which are encoded by the phoPQ operon, constitute the PhoP/PhoQ two-component system. Genome-wide transcription analysis revealed that heterologous expression of the RstB protein, a sensor of the RstA/RstB two-component system, leads to enhanced transcription of PhoP-activated genes in wild-type Salmonella. We determined that RstB-induction increases the levels of phoP mRNA as well as PhoP protein, while lack of the phoPQ genes abolishes RstB-promoted transcription of the PhoP-regulated genes. This regulatory function of RstB did not require its enzymatic activities, and thus the truncated RstB protein containing only periplasmic and transmembrane regions was able to promote PhoP-activated transcription. The RstB protein appeared to target the PhoQ sensor rather than the PhoP response regulator because RstB-induction failed to enhance transcription of the PhoP-regulated genes in a strain maintaining the normal PhoP function, even without PhoQ.
Nam
Daesil
D
Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 440-746, Korea.
Choi
Eunna
E
Kweon
Dae-Hyuk
DH
Shin
Dongwoo
D
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D009876:Operon; D010766:Phosphorylation; D010957:Plasmids / Q000737:chemistry / Q000235:genetics; D011401:Promoter Regions, Genetic; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C079792:PhoQ protein, Bacteria; C061064:PhoP protein, Bacteria; D008274:Magnesium