A novel mode of regulation of the Staphylococcus aureus catabolite control protein A (CcpA) mediated by Stk1 protein phosphorylation.

The Staphylococcus aureus serine/threonine protein kinase Stk1 (also known as PknB) affects different key pathways such as cell wall metabolism, antibiotic susceptibility, and regulation of virulence. Here we report that the catabolite control protein A (CcpA), a highly conserved regulator of carbon catabolite repression and virulence in a number of gram-positive pathogens, was efficiently phosphorylated in vitro and in vivo by Stk1 in S. aureus, whereas the CcpA homologues of Bacillus subtilis and Bacillus anthracis were not affected by the Stk1 orthologue PrkC.

The Staphylococcus aureus autoinducer-2 synthase LuxS is regulated by Ser/Thr phosphorylation.

The Staphylococcus aureus autoinducer-2 (AI-2) producer protein LuxS is phosphorylated by the Ser/Thr kinase Stk1 at a unique position, Thr14. The enzymatic activity of the phosphorylated isoform of LuxS was abrogated compared to that of nonphosphorylated LuxS, thus providing the first evidence of an AI-2-producing enzyme regulated by phosphorylation and demonstrating that S. aureus possesses an original and specific system for controlling AI-2 synthesis.