The membrane-bound histidine kinase sensor protein is NarQ. The cytoplasmic response regulator protein is NarP. Both Nitrate and Nitrite can stimulate the phospholylation of NarP via NarQ. Some of list the genes regulated by the response regulator proteins are listed. In contrast to the differential effect of nitrate and nitrite on NarX activity with respect to NarL in E.coli, the response of NarQ to either nitrate or nitrite is the same.