Member of the two-component regulatory system FilI/FilRs, which is involved in the regulation of methanogenesis. Autophosphorylates and specifically transfers the phosphoryl group to both FilR1 and FilR2. Could also catalyze the synthesis of the quorum sensing (QS) signal molecules carboxyl-acyl homoserine lactones (AHLs), which regulate the transition of the cellular morphology from short cells to filaments and of the carbon metabolic flux from biomass formation to methane production. ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. Transcriptionally regulated by FilR1 (PubMed:24748383). Transcript level increases with cell density (PubMed:22237544). Autophosphorylated.