Member of the two-component regulatory system NarS/NarL that regulates genes involved in aerobic nitrate metabolism (PubMed:25659431). Upon phosphorylation by NarS, functions as a transcription regulator by direct binding to promoter regions of target genes together with DevR to regulate their expression during aerobic nitrate metabolism (PubMed:25659431). Monomer in solution (PubMed:19052358). Interacts with DevR (PubMed:25659431). Phosphorylated by NarS. Mutants show no change in virulence in mouse model of infection. Was identified as a high-confidence drug target.