Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Mol Microbiol. 2012 Oct;86(2):331-48. doi: 10.1111/j.1365-2958.2012.08198.x. Epub 2012 Aug 27.

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

Author information

  • 1Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN 46408, USA.

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.

© 2012 Blackwell Publishing Ltd.

PMID:
22882143
[PubMed - indexed for MEDLINE]
PMCID:
PMC3468659
Free PMC Article

Images from this publication.See all images (8)Free text

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Blackwell Publishing Icon for PubMed Central
    Loading ...
    Write to the Help Desk