Member of the two-component regulatory system ArlS/ArlR involved in the regulation of adhesion, autolysis, multidrug resistance and virulence. ArlS probably functions as a sensor protein kinase which is autophosphorylated at a histidine residue and transfers its phosphate group to ArlR (By similarity). ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. Autophosphorylated.