Disease relevance of ECs3438

• Fine-tuning of the Escherichia coli sigmaE envelope stress response relies on multiple mechanisms to inhibit signal-independent proteolysis of the transmembrane anti-sigma factor, RseA [1].

High impact information on ECs3438

• DegS senses misfolded protein in the periplasm, undergoes autoactivation, and cleaves the antisigma factor RseA [2].
• Thus, the function of RseB, widely conserved among bacteria using the sigma(E) pathway, and the second role of DegS (in addition to RseA proteolysis initiation) is to improve the performance characteristics of this signal transduction system [1].
• We present evidence that the putative inner membrane serine protease, DegS, is responsible for this regulated degradation of RseA [3].
• It was also found that a glutamine-rich region in the periplasmic domain of RseA was required for the avoidance of the YaeL-mediated proteolysis in the absence of site-1 cleavage [4].
• Variant sigma(E) proteins with amino acid substitutions at residues 178, 181, or 183 do not associate with RseA [5].

Biological context of ECs3438

• RseA interacts with residues 154-191 of sigma(E), a site that is homologous to region 4, the sigma factor binding site for promoter DNA [5].
• DegS promotes the destabilization of the sigma (E)-specific anti-sigma factor RseA, thereby releasing sigma (E) to direct gene expression [6].
• Additionally, we show that the antisigma factor RseA is phosphorylated at the N-terminally located Tyr-38 and that this phosphorylation presumably alters its binding affinity towards sigmaE [7].

Anatomical context of ECs3438

• The N-terminal domain of RseA sequesters sigmaE in the cytoplasmic membrane, preventing its association with core RNA polymerase [8].

References