Summary of the sigmaE and Cpx envelope stress responses

Regulatory pathway
Activating signal
Signal transduction mechanism
Regulon members
Physiological roles
sigmaE
Misfolded OM or periplasmic proteins
Relief of inhibitory interacions between the membrane-anchored sigma factor RseA and sigmaE
Envelope folding factor FkpA, envelope protease DegP, rpoE, rseABC, rpoH, virulence factors, unidentified members
Ensures proper OMP folding
Cpx
IM associated aggregates of misfolded protein
Alterations in phosphotransfer reactions between the HK CpxA and RR CpxR
Envelope folding factors (DsbA, PpiA, PpiD), envelope protease DegP, cpxRA, cpxP, virulence factors, unidentified members
Ensures properly timed biogenesis of pili, others?