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The auxiliary protein complex SaePQ activates the phosphatase activity of sensor kinase SaeS in the SaeRS two‐component system of S taphylococcus aureus
Author(s) -
Jeong DoWon,
Cho Hoonsik,
Jones Marcus B.,
Shatzkes Kenneth,
Sun Fei,
Ji Quanjiang,
Liu Qian,
Peterson Scott N.,
He Chuan,
Bae Taeok
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.08198.x
Subject(s) - dephosphorylation , phosphatase , biology , response regulator , phosphorylation , kinase , two component regulatory system , operon , biochemistry , microbiology and biotechnology , protein kinase a , gene , bacterial protein , mutant , escherichia coli
Summary 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 S taphylococcus 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.