A probable intramembrane site-2 protease (S2P) that cleaves type-2 transmembrane proteins within their membrane-spanning domains. Degrades PbpB (PBP3, FtsI) under conditions of oxidatives stress; degradation is inhibited by Wag31-PbpB interaction. Also cleaves anti-sigma factors RskA, RslA and RslM. Site-1 proteases have not yet been identified in this organism. Regulated intramembrane proteolysis (RIP) occurs when an extracytoplasmic signal (possibly oxidative stress) triggers a concerted proteolytic cascade to transmit information and elicit cellular responses. The membrane-spanning regulatory substrate protein (includes anti-sigma factors RskA, RslA, RsmA, and PbpB) is first cut extracytoplasmically (site-1 protease, S1P), then within the membrane itself (site-2 protease, S2P, this entry), while cytoplasmic proteases finish degrading the regulatory protein, liberating the effector protein (ECF sigma factors SigK, SigL and SigM). Proteolysis is inhibited by Wag31; when Wag31 is non-functional oxidative stress increases proteolysis. Not essential. No degradation of PbpB (PBP3, FtsI) in the presence of mutant Wag31 upon H(2)O(2) exposure (PubMed:19496931). Altered processing of anti-sigma factors RskA, RslA and RslM (PubMed:20545848). Belongs to the peptidase M50B family.