A Dual Regulatory Role of the PhoU Protein in Salmonella Typhimurium

Soomin Choi, Gyunghwa Jeong, Eunna Choi, Eun Jin Lee

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Bacteria utilize two-component regulatory systems to sense and respond to their surroundings. Unlike other two-component systems that directly sense through a sensory domain in the histidine kinase (HK), the PhoB/PhoR two-component system requires additional proteins, including the PstSCAB phosphate transporter and the PhoU protein, to sense phosphate levels. Although PhoU is involved in phosphate signaling by connecting the PstSCAB transporter and PhoR histidine kinase, the mechanism by which PhoU controls expression of pho regulon genes has not yet been clearly understood. Here, we identified PhoU residues required for interacting with PhoR histidine kinase from the intracellular pathogen Salmonella enterica serovar Typhimurium. The PhoU Ala147 residue interacts with the PhoR PAS domain and is involved in repressing pho expression in high phosphate. Unexpectedly, the PhoU Arg184 residue interacts with the PhoR histidine kinase domain and is required for activating pho expression in low Mg21 by increasing PhoR autophosphorylation, revealing its new function. The substitution of the Arg184 to Gly codon decreased Salmonella virulence both in macrophages and in mice, suggesting that PhoU’s role in promoting PhoR autophosphorylation is required during Salmonella infection.

Original languageEnglish
Issue number3
Publication statusPublished - 2022 Jun

Bibliographical note

Funding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2022R1A2B5B02002256 and NRF-2020M3A9H5104235 to E.-J.L. and NRF-2021R1I1A1A01043879 to E.C.), the Ministry of Education (NRF-2020R1A6A3A13076438 to S.C.), and a grant from Korea University.

Publisher Copyright:
© 2022 American Society for Microbiology. All rights reserved.


  • PhoB/ PhoR two-component system
  • low Mg
  • phosphate limitation
  • phosphate limitation
  • pst phosphate-transport system

ASJC Scopus subject areas

  • Microbiology
  • Virology


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