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.
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.
Howell
Alistair
A
Department of Genetics, Smurfit Institute, Trinity College Dublin, Dublin 2, Ireland.
Dubrac
Sarah
S
Noone
David
D
Varughese
Kottayil I
KI
Devine
Kevin
K
D000469:Alkaline Phosphatase; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000254:growth & development* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D000071677:Histidine Kinase; D008969:Molecular Sequence Data; D009154:Mutation; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D015398:Signal Transduction
D001426:Bacterial Proteins; D010710:Phosphates; C119939:YycF protein, Bacteria; C061279:PhoR protein, Bacteria; C061064:PhoP protein, Bacteria; D011494:Protein Kinases; D018844:Cyclin-Dependent Kinases; D000071677:Histidine Kinase; D000469:Alkaline Phosphatase