A novel mode of regulation of the Staphylococcus aureus Vancomycin-resistance-associated response regulator VraR mediated by Stk1 protein phosphorylation.
The Staphylococcus aureus Vancomycin-resistance-associated response regulator VraR is known as an important response regulator, member of the VraTSR three-component signal transduction system that modulates the expression of the cell wall stress stimulon in response to a number of different cell wall active antibiotics. Given its crucial role in regulating gene expression in response to antibiotic challenges, VraR must be tightly regulated. We report here for the first time in S. aureus convergence of two major signal transduction systems, serine/threonine protein kinase and two (three)-component systems. We demonstrate that VraR can be phosphorylated by the staphylococcal Ser/Thr protein kinase Stk1 and that phosphorylation negatively affects its DNA-binding properties. Mass spectrometric analyses and site-directed mutagenesis identified Thr106, Thr119, Thr175 and Thr178 as phosphoacceptors. A S. aureus ΔvraR mutant expressing a VraR derivative that mimics constitutive phosphorylation, VraR_Asp, still exhibited markedly decreased antibiotic resistance against different cell wall active antibiotics, when compared to the wild-type, suggesting that VraR phosphorylation may represent a novel and presumably more general mechanism of regulation of the two (three)-component systems in staphylococci.
Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier II, CNRS UMR 5235, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
Marc J
MJ
Canova
Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier II, CNRS UMR 5235, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
Grégory
G
Baronian
Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier II, CNRS UMR 5235, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
Solène
S
Brelle
Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U554, Université Montpellier I et II, Montpellier, France.
Martin
M
Cohen-Gonsaud
Institute of Medical Microbiology and Hygiene, University of Saarland Hospital, Homburg, Germany.
Markus
M
Bischoff
Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier II, CNRS UMR 5235, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France. Electronic address: virginie.molle@univ-montp2.fr.
Virginie
V
Molle
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D008826:Microbial Sensitivity Tests; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D013211:Staphylococcus aureus / Q000235:genetics*; D014640:Vancomycin / Q000378:metabolism / Q000494:pharmacology; D037521:Virulence Factors / Q000378:metabolism*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D037521:Virulence Factors; C478170:VraR protein, Staphylococcus aureus; D014640:Vancomycin; D017346:Protein Serine-Threonine Kinases; C546823:Stk1 protein, Staphylococcus aureus
Antibiotic resistance; Phosphorylation; Ser/Thr protein kinase; Staphylococcus aureus; VraR