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Two unique phosphorylation‐driven signaling pathways crosstalk in Staphylococcus aureus: STK1 meets GraR
Author(s) -
Fridman Michael,
GolemiKotra Dasantila
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1038.5
Subject(s) - phosphorylation , crosstalk , biology , signal transduction , protein phosphorylation , threonine , bacillus subtilis , response regulator , biochemistry , microbiology and biotechnology , gene , genetics , serine , protein kinase a , bacteria , bacterial protein , physics , optics
The Stk1/Stp1 and GraSR signal transduction pathways are two distinct pathways in Staphylococcus aureus that rely on reversible phosphorylation processes in transducing external stimuli intracellularly. Our study shows for the first time that these two systems interact in S. aureus. GraR undergoes phosphorylation by Stk1 at three threonine residues in the DNA‐binding domain. Phosphorylation by Stk1 depends on the structural integrity of GraR and amino acid sequences flanking the phosphorylation sites. Its homolog in Bacillus subtilis, BceR, which shares 56% sequence identity with GraR, does not undergo phosphorylation. In addition, an unrelated response regulator of S. aureus, VraR, does not undergo phosphorylation by Stk1. These findings provide strong evidence that GraR is a target of Stk1. Stk1‐dependent phosphorylation of GraR increases its DNA‐binding affinity to one of the GraR‐target promoters. The crosstalk between these two otherwise independent pathways may facilitate S. aureus adaptation to diverse environmental cues and mediate its virulence. This work was supported by the Natural Sciences and Engineering Research Council of Canada and the Ministry of Economic Development and Innovation (Ontario, Canada).