Hudak, KatalinAudette, Gerald F.McDermott, John2016-08-032016-08-032013-09http://hdl.handle.net/10315/31731Staphylococcus aureus coordinates gene expression at appropriate times throughout its life cycle. The work herein demonstrates S. aureus serine-threonine kinase (Stk1) can phosphorylate the response regulator GraR in vitro. Phosphorylation was confirmed by mass spectrometry and specifically occurs at the DNA-binding domain at three threonine positions: Thr128, 130 and 149. Stk1 could not phosphorylate BceR, a GraR homolog with 56% sequence similarity. We have also discovered, through in vivo work, novel phenotypes of an S. aureus [delta]graR knockout. It is shown that GraR plays a role in proper cell growth, division and wall teichoic acid maintenance. [delta]graR mutant complemented with ectopically expressed GraR-WT reverts phenotypes to normal, whereas GraR-D51N does not. Collectively our data suggest a novel, more global, regulatory role for the GraSR system. Understanding signaling and post-translational modification networks and their downstream effects is essential in order to rationally develop new strategies to treat S. aureus infections.Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Electronic Thesis or DissertationStaphylococcus aureusPhosphorylationSerine-threonine kinaseStk1GraRGenetics