Member of the two-component regulatory system CusS/CusR involved in response to copper and silver. Activates the expression of cusCFBA, hiuH and plasmid pRJ1004 gene pcoE in response to increasing levels of copper or silver ions. Can also increase the basal-level expression of copper resistance gene operon pcoABCD. Phosphorylated by CusS. The cus system plays an important role in copper tolerance under anaerobic growth and, under extreme copper stress, in aerobic growth. HprSR and CusSR form a unique regulation system, where both two-component systems recognize and regulate the same set of genes, but under different environmental conditions. HprSR plays a role in H(2)O(2) response regulation, while CusSR plays a role in Cu(2+) response regulation (PubMed:25568260, PubMed:27983483). Under low protein concentrations, the two regulators recognize and transcribe both hiuH and cusC promoters, albeit at different efficiency, apparently in a collaborative fashion (PubMed:27983483).