An anti-sigma factor for extracytoplasmic function (ECF) sigma factor sigma-E (RpoE). ECF sigma factors are held in an inactive form by an anti-sigma factor until released by regulated intramembrane proteolysis (RIP). RIP occurs when an extracytoplasmic signal (periplasmic or acid stress or heat shock) triggers a concerted proteolytic cascade to transmit information and elicit cellular responses. The membrane-spanning regulatory substrate protein is first cut periplasmically (site-1 protease, S1P, DegS), then within the membrane itself (site-2 protease, S2P, RseP), while cytoplasmic proteases finish degrading the anti-sigma factor, liberating sigma-E (Probable). In this organism acid stress response does not require DegS degradation. Responds differently to heat shock versus acid shock; degradation in response to heat shock requires sequential DegS and RseP action, whereas degradation in response to acid shock requires only RseP. Interacts 1:1 with ECF RNA polymerase sigma-E (RpoE); this inhibits the interaction of sigma-E with the RNA polymerase catalytic core and leads to a decreased expression of sigma-E-regulated genes. Interacts with RseB (By similarity). Sequentially cleaved by DegS (a site-1 protease) in its periplasmic domain between Val-148 and Ser-149, then by RseP (a site-2 protease) between positions Ala-108 and Cys-109. The N-terminal fragment is then degraded by primarily ClpX-ClpP in an ATP-dependent fashion. Sequential cleavage by DegS, RseP and ClpX-ClpP frees RpoE from RseA (Probable). Derepression and constitutive activation of sigma-E function, consequently loss of acid stress response. Belongs to the RseA family.