A tyrosine kinase and its activator control the activity of the CtsR heat shock repressor in B. subtilis

EMBO J. 2005 Oct 5;24(19):3435-45. doi: 10.1038/sj.emboj.7600780. Epub 2005 Sep 15.


The soil bacterium Bacillus subtilis possesses a fine-tuned and complex heat stress response system. The repressor CtsR, whose activity is regulated by its modulators McsA and McsB, controls the expression of the cellular protein quality control genes clpC, clpE and clpP. Here, we show that the interaction of McsA and McsB with CtsR results in the formation of a ternary complex that not only prevents the binding of CtsR to its target DNA, but also results in a subsequent phosphorylation of McsB, McsA and CtsR. We further demonstrate that McsB is a tyrosine kinase that needs McsA to become activated. ClpC inhibits the kinase activity of McsB, indicating a direct role in initiating CtsR-controlled heat shock response. Interestingly, the kinase domain of McsB is homologous to guanidino phosphotransferase domains originating from eukaryotic arginine and creatine kinases. Mutational analysis of key residues of the guanidino kinase domain demonstrated that McsB utilizes this domain to catalyze the tyrosine phosphorylation. McsB represents therefore a new kind of tyrosine kinase, driven by a guanidino phosphotransferase domain.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Amino Acid Sequence
  • Bacillus subtilis / enzymology*
  • Bacillus subtilis / physiology
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Blotting, Western
  • Electrophoresis, Polyacrylamide Gel
  • Electrophoretic Mobility Shift Assay
  • Gene Expression Regulation, Enzymologic*
  • Heat-Shock Proteins / metabolism
  • Heat-Shock Response / physiology*
  • Immunoprecipitation
  • Models, Molecular*
  • Molecular Sequence Data
  • Phosphorylation
  • Protein Kinases / genetics*
  • Protein Kinases / metabolism*
  • Repressor Proteins / metabolism*


  • Bacterial Proteins
  • ClpC protein, Bacteria
  • CtsR protein, bacteria
  • Heat-Shock Proteins
  • McsA protein, Bacillus subtilis
  • Repressor Proteins
  • Protein Kinases
  • McsB protein, Bacillus subtilis
  • Adenosine Triphosphatases
  • ClpE protein, bacteria