Negatively modulates the activity of sigma-E (RpoE) by stabilizing RseA under non-stress conditions. Although not essential for association of sigma-E with Rsea it increases their affinity 2- to 3-fold. When bound to RseA it prevents proteolysis by DegS, which is probably relieved by lipopolysaccharide binding (LPS). Binding to RseA is inhibited by LPS fragments; phosphorylated N-acetylglucosamine (GlcNAc) with N-linked acyl chains are minimally necessary to disrupt binding to RseA. Once RseB is no longer bound to RseA the latter is susceptible to DegS degradation. Thus if periplasmic LPS levels increase the sigma-E regulon is induced. Homodimer. Interacts with RseA with 1:1 stoichiometry. Binding to LPS stabilzes a homotetramer that does not bind RseA. Partially associates with the inner membrane via RseA. The N-terminal domain (residues 24-203) is responsible for oligomerization, while the C-terminal domain (residues 222-318) interacts with RseA. About 2-fold increased sigma-E activity, 2-fold decrease in stability of RseA. Part of the rseD-rpoE-rseA-rseB-rseC operon (PubMed:9159522, PubMed:9159523, PubMed:28924029). Belongs to the RseB family.