How the PhoP/PhoQ System Controls Virulence and Mg2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution

Microbiol Mol Biol Rev. 2021 Aug 18;85(3):e0017620. doi: 10.1128/MMBR.00176-20. Epub 2021 Jun 30.

Abstract

The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.

Keywords: ATP; Salmonella; acidic pH; antimicrobial peptides; gene silencing; lipopolysaccharide; promoter architecture; protein synthesis; proteolysis; two-component system.

Publication types

  • Review

MeSH terms

  • Animals
  • Bacterial Proteins / genetics*
  • Evolution, Molecular
  • Histidine Kinase / genetics*
  • Homeostasis / genetics*
  • Humans
  • Magnesium / metabolism*
  • Salmonella typhimurium / genetics
  • Signal Transduction / genetics*
  • Transcription Factors / genetics
  • Transcription, Genetic / genetics
  • Virulence / genetics*

Substances

  • Bacterial Proteins
  • Transcription Factors
  • PhoP protein, Bacteria
  • Histidine Kinase
  • ssrA protein, Salmonella typhimurium
  • Magnesium