A site-2 regulated intramembrane protease (S2P) that cleaves the peptide bond between 'Ala-108' and 'Cys-109' in the transmembrane region of RseA. Part of a regulated intramembrane proteolysis (RIP) cascade. Acts on DegS-cleaved RseA to release the cytoplasmic domain of RseA. This provides the cell with sigma-E (RpoE) activity through the proteolysis of RseA (By similarity). Interacts with RseA. The 2 circularly premutated PDZ domains act to negatively regulate protease action on intact RseA. Regulated intramembrane proteolysis (RIP) occurs when an extracytoplasmic signal triggers a concerted proteolytic cascade to transmit information and elicit cellular responses. A membrane-spanning regulatory substrate protein is first cut extracytoplasmically (site-1 protease, S1P), then within the membrane itself (site-2 protease, S2P, this enzyme), while cytoplasmic proteases finish degrading the regulatory protein, liberating the effector protein (By similarity). Belongs to the peptidase M50B family.