Distinct phosphorylation and dephosphorylation dynamics of protein arginine kinases revealed by fluorescent activity probes

Protein arginine (Arg) phosphorylation regulates stress responses and virulence in bacteria. With fluorescent activity probes, we show that McsB, a protein Arg kinase, can dephosphorylate phosphoarginine (pArg) residues to produce ATP from ADP, implicating the dynamic control of protein pArg levels by the kinase even without a phosphatase.