In the bacterial cytosol, ATP-dependent protein degradation is performed by several different chaperone-protease pairs, including ClpAP. ClpS directly influences the ClpAP machine by binding to the N-terminal domain of the chaperone ClpA. The degradation of ClpAP substrates, both SsrA-tagged proteins and ClpA itself, is specifically inhibited by ClpS. ClpS modifies ClpA substrate specificity, potentially redirecting degradation by ClpAP toward aggregated proteins [1].

1: ClpS, a substrate modulator of the ClpAP machine. Dougan DA, Reid BG, Horwich AL, Bukau B; Mol Cell 2002;9:673-683. PMID:11931773

2: Structural analysis of the adaptor protein ClpS in complex with the N-terminal domain of ClpA. Zeth K, Ravelli RB, Paal K, Cusack S, Bukau B, Dougan DA; Nat Struct Biol 2002;9:906-911. PMID:12426582