Member of a two-component regulatory system HprR/HprS involved in response to hydrogen peroxide (PubMed:25568260, PubMed:27983483). Regulates the expression of at least 5 operons, cyoABCDE, hprRS, hiuH, cusRS and cusCFBA. Bifunctional regulator that acts as an activator and a repressor (PubMed:25568260). Phosphorylated by HprS. 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).