Sigma factors are initiation factors that promote the attachment of RNA polymerase (RNAP) to specific initiation sites and are then released (PubMed:7889935, PubMed:2691330, PubMed:9159522, PubMed:9159523). Extracytoplasmic function (ECF) sigma-E controls the envelope stress response, responding to periplasmic protein stress, increased levels of periplasmic lipopolysaccharide (LPS) as well as heat shock (PubMed:7889935) and oxidative stress; it controls protein processing in the extracytoplasmic compartment. The 90 member regulon consists of the genes necessary for the synthesis and maintenance of both proteins and LPS of the outer membrane (PubMed:7889934, PubMed:11274153, PubMed:16336047). Indirectly activates transcription of csrB and csrC, 2 sRNAs that antagonize translational regulator CsrA, linking envelope stress, the stringent response and the catabolite repression systems (PubMed:28924029). ECF sigma-E is held in an inactive form by its cognate anti-sigma factor (RseA) until released by regulated intramembrane proteolysis (RIP). RIP occurs when an extracytoplasmic signal (periplasmic stress and excess LPS) triggers a concerted proteolytic cascade to transmit information and elicit cellular responses. The anti-sigma factor RseA is an inner membrane protein, binding sigma-E in the cytoplasm and RseB in the periplasm. RseA is first cut extracytoplasmically (site-1 protease, S1P, by DegS), then within the membrane itself (site-2 protease, S2P, by RseP), while cytoplasmic proteases (predominantly ClpX-ClpP) finish degrading the regulatory protein, liberating sigma-E (PubMed:15371343). Degradation of RseA requires 2 signals to activate DegS; an outer membrane protein (OMP) signal activates DegS, while an LPS signal causes release of RseB from RseA, freeing RseA to be cleaved (PubMed:23687042). The rate-limiting step in this protease cascade is the first signal-sensing cleavage (half-life about 1 minute) (PubMed:17210793). Interacts transiently with the RNAP catalytic core formed by RpoA, RpoB, RpoC and RpoZ (2 alpha, 1 beta, 1 beta' and 1 omega subunit) to form the RNAP holoenzyme that can initiate transcription (PubMed:12016219, PubMed:12718891, PubMed:7889935, PubMed:2691330). Interacts 1:1 with anti-sigma-E factor RseA which prevents binding to RNAP catalytic core (PubMed:9159522, PubMed:9159523, PubMed:11777003, PubMed:12016219, PubMed:15371343, PubMed:12718891). An N-terminal (residues 1-108) RseA sigma-E complex also interacts with SspB (PubMed:15371343). Associates with the inner membrane via RseA (PubMed:9159522, PubMed:11777003). Induced after shifting to 50 degrees Celsius (at protein level) (PubMed:2691330). Induced when the level of outer membrane proteins (OMP) increases (at protein level) (PubMed:8276244, PubMed:10500101). Induced as periplasmic levels of LPS levels increase (PubMed:23687042). Induced by misfolded periplasmic proteins (PubMed:9351822). Transcription positively autoregulated (via promoter P2) (PubMed:7889935). Transcription slightly induced by elevated temperatures (PubMed:7889934). Transiently induced by cold shock in a PNPase-dependent fashion (PubMed:14527658). Translation repressed by CsrA which binds to 3 sites in the 5'-UTR which occludes the ribosome binding site (PubMed:28924029). Translation is coupled to upstream leader peptide RseD, whose stop codon overlaps with the start codon of rpoE; when coupling is eliminated translation is decreased by about 50% (PubMed:28924029). Part of the rseD-rpoE-rseA-rseB-rseC operon (PubMed:9159522, PubMed:9159523, PubMed:28924029). The sigma-70 factor domain-2 mediates sequence-specific interaction with the -10 element in promoter DNA, and plays an important role in melting the double-stranded DNA and the formation of the transcription bubble. The sigma-70 factor domain-2 mediates interaction with the RNA polymerase subunits RpoB and RpoC. The sigma-70 factor domain-4 contains a helix-turn-helix (H-T-H) motif that mediates interaction with the -35 element in promoter DNA. The domain also mediates interaction with the RNA polymerase subunit RpoA. Interactions between sigma-70 factor domain-4 and anti-sigma factors prevents interaction of sigma factors with the RNA polymerase catalytic core. Reduced viability at 37 degrees Celsius, death at 42 degrees Celsius (PubMed:7889935). Loss of transcription from rpoE-dependent promoters (PubMed:7889935). Increased sensitivity to outer membrane disruption (PubMed:7889934). Belongs to the sigma-70 factor family. ECF subfamily. Extended N-terminus.