<b>Ser/Thr protein kinase Stk1 phosphorylates the key transcriptional regulator AlgR to modulate virulence and resistance in </b><b><i>Pseudomonas aeruginosa</i></b>

We identified AlgR, an important transcriptional regulator, as a substrate for Stk1, with its phosphorylation at the Ser143 site catalyzed by Stk1. Intriguingly, both the deletion of <i>stk1</i> and the mutation of Ser143 of AlgR to Ala result in similar changes in some physiological functions. Furthermore, assays of <i>algR</i> expression in these strains suggest that changes in the phosphorylation state of AlgR, rather than its expression level, underlie changes in these physiological functions. These findings uncover Stk1-mediated phosphorylation of AlgR as an important mechanism for regulating virulence and resistance in <i>Pseudomonas aeruginosa</i>.