Structural highlights
Function
[PHOQ_SALTY] Member of the two-component regulatory system PhoP/PhoQ which regulates the expression of genes involved in virulence, adaptation to acidic and low Mg(2+) environments and resistance to host defense antimicrobial peptides. Essential for intramacrophage survival of S.typhimurium. In low periplasmic Mg(2+), PhoQ functions as a membrane-associated protein kinase that undergoes autophosphorylation and subsequently transfers the phosphate to PhoP, resulting in the expression of PhoP-activated genes (PAG) and repression of PhoP-repressed genes (PRG). In high periplasmic Mg(2+), acts as a protein phosphatase that dephosphorylates phospho-PhoP, resulting in the repression of PAG and may lead to expression of some PRG. Essential for transcription of spiC inside macrophages by controlling the expression of the two-component regulatory system SsrB/SpiR (SsrA) and Pir at transcriptional and post-transcriptional levels respectively. Promotes expression of the two-component regulatory system PmrA/PmrB via activation of pmrD gene. Is required to attenuate bacterial growth within fibroblast cells and to enhance bacterial resistance to bile in intestinal cells. Negatively regulates prgH, which is required for invasion of epithelial cells. Involved in acid tolerance.[1] [2] [3]
References
- ↑ Miller SI, Kukral AM, Mekalanos JJ. A two-component regulatory system (phoP phoQ) controls Salmonella typhimurium virulence. Proc Natl Acad Sci U S A. 1989 Jul;86(13):5054-8. PMID:2544889
- ↑ Bearson BL, Wilson L, Foster JW. A low pH-inducible, PhoPQ-dependent acid tolerance response protects Salmonella typhimurium against inorganic acid stress. J Bacteriol. 1998 May;180(9):2409-17. PMID:9573193
- ↑ Sanowar S, Le Moual H. Functional reconstitution of the Salmonella typhimurium PhoQ histidine kinase sensor in proteoliposomes. Biochem J. 2005 Sep 15;390(Pt 3):769-76. PMID:15910283 doi:http://dx.doi.org/BJ20050060