The auxiliary protein complex SaePQ activates the phosphatase activity of sensor kinase SaeS in the SaeRS two-component system of Staphylococcus aureus

Do Won Jeong, Hoonsik Cho, Marcus B. Jones, Kenneth Shatzkes, Fei Sun, Quanjiang Ji, Qian Liu, Scott N. Peterson, Chuan He, Taeok Bae

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

In bacterial two-component regulatory systems (TCSs), dephosphorylation of phosphorylated response regulators is essential for resetting the activated systems to the pre-activation state. However, in the SaeRS TCS, a major virulence TCS of Staphylococcus aureus, the mechanism for dephosphorylation of the response regulator SaeR has not been identified. Here we report that two auxiliary proteins from the sae operon, SaeP and SaeQ, form a protein complex with the sensor kinase SaeS and activate the sensor kinase's phosphatase activity. Efficient activation of the phosphatase activity required the presence of both SaeP and SaeQ. When SaeP and SaeQ were ectopically expressed, the expression of coagulase, a sae target with low affinity for phosphorylated SaeR, was greatly reduced, while the expression of alpha-haemolysin, a sae target with high affinity for phosphorylated SaeR, was not, demonstrating a differential effect of SaePQ on sae target gene expression. When expression of SaePQ was abolished, most sae target genes were induced at an elevated level. Since the expression of SaeP and SaeQ is induced by the SaeRS TCS, these results suggest that the SaeRS TCS returns to the pre-activation state by a negative feedback mechanism.

Original languageEnglish (US)
Pages (from-to)331-348
Number of pages18
JournalMolecular Microbiology
Volume86
Issue number2
DOIs
StatePublished - Oct 2012
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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