Member of the two-component regulatory system FleS/FleR that regulates the expression of multiple genes involved in flagellar synthesis, adhesion, swarming, motility and antibiotic resistance (PubMed:30877999, PubMed:7591148). May function as a membrane-associated protein kinase that phosphorylates FleR in response to environmental signals leading to activation of specific gene promoters (Probable). ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. Mutant shows severe swimming defect.