FEATURES

FAMILY

DESCRIPTION

Also known as SIGH_MYCTU, sigH, rpoE. Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. Extracytoplasmic function (ECF) sigma factors are held in an inactive form by a cognate anti-sigma factor (RshA) until released. This sigma factor is involved in heat shock and oxidative stress responses; it positively regulates the expression of itself, sigE, sigB and a number of transcriptional regulators as well as other effectors of heat and oxidative stress, leading to direct and indirect control of up to 25% of the bacterial genome. Modulates expression of host genes for intercrine beta (chemokine CC) and apoptosis, altering the host immune response. Interacts transiently with the RNA polymerase catalytic core formed by RpoA, RpoB, RpoC and RpoZ (2 alpha, 1 beta, 1 beta' and 1 omega subunit) to form the RNA polymerase holoenzyme that can initiate transcription. Interacts (affinity=15 nM) 1:1 (via sigma-70 factor domain-4) with RshA under reducing conditions; the complex is disrupted as temperatures rise. Phosphorylation of RshA decreases its interaction with SigH, leading to increased SigH-mediated transcription.

EXTERNAL LINKS

sigH

ECF RNA polymerase sigma factor SigH

sigH

Molecular Synopsis