Interactions between the YycFG and PhoPR two-component systems in Bacillus subtilis: the PhoR kinase phosphorylates the non-cognate YycF response regulator upon phosphate limitation

Mol Microbiol. 2006 Feb;59(4):1199-215. doi: 10.1111/j.1365-2958.2005.05017.x.


Two-component signal transduction systems (TCS) are an important mechanism by which bacteria sense and respond to their environment. Although each two-component system appears to detect and respond to a specific signal(s), it is now evident that they do not always act independently of each other. In this paper we present data indicating regulatory links between the PhoPR two-component system that participates in the cellular response to phosphate limitation, and the essential YycFG two-component system in Bacillus subtilis. We show that the PhoR sensor kinase can activate the YycF response regulator during a phosphate limitation-induced stationary phase, and that this reaction occurs in the presence of the cognate YycG sensor kinase. Phosphorylation of YycF by PhoR also occurs in vitro, albeit at a reduced level. However, the reciprocal cross-phosphorylation does not occur. A second level of interaction between PhoPR and YycFG is indicated by the fact that cells depleted for YycFG have a severely deficient PhoPR-dependent phosphate limitation response and that YycF can bind directly to the promoter of the phoPR operon. YycFG-depleted cells neither activate expression of phoA and phoPR nor repress expression of the essential tagAB and tagDEF operons upon phosphate limitation. This effect is specific to the PhoPR-dependent phosphate limitation response because PhoPR-independent phosphate limitation responses can be initiated in YycFG-depleted cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase
  • Amino Acid Sequence
  • Bacillus subtilis / growth & development*
  • Bacillus subtilis / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cyclin-Dependent Kinases / metabolism
  • Histidine Kinase
  • Molecular Sequence Data
  • Mutation
  • Phosphates / metabolism
  • Phosphorylation
  • Promoter Regions, Genetic
  • Protein Kinases / chemistry
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Protein Structure, Secondary
  • Signal Transduction*


  • Bacterial Proteins
  • Phosphates
  • YycF protein, Bacteria
  • PhoR protein, Bacteria
  • PhoP protein, Bacteria
  • Protein Kinases
  • Cyclin-Dependent Kinases
  • Histidine Kinase
  • Alkaline Phosphatase