Member of the two-component regulatory system PprA/PprB involved in biofilm formation by controlling the expression of many related genes including type IVb pili major subunit flp pilin, adhesin bapA or cupE fimbriae (PubMed:21091863, PubMed:23209420, PubMed:31492668). Functions as a heme sensor histidine kinase which is autophosphorylated at a histidine residue and transfers its phosphate group to PprB (PubMed:12499175). ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. By carbon starvation. This increased expression is controlled by RpoS. Autophosphorylated. Mutant exhibits similar responses to carbon starvation stress suggesting that PprB-mediated transcriptional response is not transmitted through PprA.