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:7591148, PubMed:30877999, PubMed:8876537). May function as a transcriptional activator by direct binding to a cis-acting sequence upstream of the target genes (Probable). Deletion leads to loss of motility due to the absence of flagella as well as swimming defect (PubMed:7591148, PubMed:30877999). In addition, mutant possessing pili adheres poorly to mucins (PubMed:8876537).