Member of the two-component regulatory system CopS/CopR. Involved in the activation of copper resistance gene operon CopABCD. Phosphorylation of CopR by CopS would convert it into an active state to induce expression of the cop operon by binding to a specific site on the cop operon promoter (cop box) and possibly by facilitating the binding of RNA polymerase to the cop promoter. CopR also binds to the chromosomally encoded cop operon promoter. May also be involved in basic copper metabolism. Phosphorylated by CopS.