title: Anti-sigma factors.
abstract: Anti-sigma factors modulate the expression of numerous regulons controlled by alternative sigma factors. Anti-sigma factors are themselves regulated by either secretion from the cell (i.e. FlgM export through the hook-basal body), sequestration by an anti-anti-sigma (i.e. phosphorylation regulated partner-switching modules), or interaction with extracytoplasmic proteins or small molecule effectors (i.e. transmembrane regulators of extracytoplasmic function sigma factors). Recent highlights include the genetic description of the opposed sigma/anti-sigma binding surfaces; the unexpected role of FlgM in holoenzyme destabilization and the finding that folding of FlgM is coupled to sigma28 binding; the first structure determination for an anti-sigma antagonist; and the detailed dissection of two complex partner-switching modules in Bacillus subtilis.
mesh_terms: D001426:Bacterial Proteins; D015964:Gene Expression Regulation, Bacterial; D008957:Models, Genetic; D012808:Sigma Factor / Q000037:antagonists & inhibitors*; D013171:Spores, Bacterial / Q000502:physiology; D014764:Viral Proteins