Member of the two-component regulatory system NreB/NreC involved in the control of dissimilatory nitrate/nitrite reduction in response to oxygen. Phosphorylated NreC binds to a GC-rich palindromic sequence at the promoters of the nitrate (narGHJI) and nitrite (nir) reductase operons, as well as the putative nitrate transporter gene narT, and activates their expression. Phosphorylated by NreB.