title: RsrA, an anti-sigma factor regulated by redox change.
abstract: SigR (sigma(R)) is a sigma factor responsible for inducing the thioredoxin system in response to oxidative stress in the antibiotic-producing, Gram-positive bacterium Streptomyces coelicolor A3(2). Here we identify a redox-sensitive, sigma(R)-specific anti-sigma factor, RsrA, which binds sigma(R) and inhibits sigma(R)-directed transcription in vitro only under reducing conditions. Exposure to H(2)O(2) or to the thiol-specific oxidant diamide caused the dissociation of the sigma(R)-RsrA complex, thereby allowing sigma(R)-dependent transcription. This correlated with intramolecular disulfide bond formation in RsrA. Thioredoxin was able to reduce oxidized RsrA, suggesting that sigma(R), RsrA and the thioredoxin system comprise a novel feedback homeostasis loop that senses and responds to changes in the intracellular thiol-disulfide redox balance.
authors.affiliation: Department of Microbiology, College of Natural Sciences, and Research Center for Molecular Microbiology, Seoul National University, Seoul 151-742, Korea.
authors.forename: J G
authors.initials: JG
authors.lastname: Kang
authors.forename: M S
authors.initials: MS
authors.lastname: Paget
authors.forename: Y J
authors.initials: YJ
authors.lastname: Seok
authors.forename: M Y
authors.initials: MY
authors.lastname: Hahn
authors.forename: J B
authors.initials: JB
authors.lastname: Bae
authors.forename: J S
authors.initials: JS
authors.lastname: Hahn
authors.forename: C
authors.initials: C
authors.lastname: Kleanthous
authors.forename: M J
authors.initials: MJ
authors.lastname: Buttner
authors.forename: J H
authors.initials: JH
authors.lastname: Roe
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D004220:Disulfides / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000037:antagonists & inhibitors*; D013379:Substrate Specificity; D020349:Surface Plasmon Resonance; D013879:Thioredoxins / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004220:Disulfides; C121147:RsrA protein, Streptomyces coelicolor; D012808:Sigma Factor; D014157:Transcription Factors; D013879:Thioredoxins