Helmann J D
Section of Microbiology, Wing Hall, Cornell University, Ithaca, NY 14853-8101, USA.
Curr Opin Microbiol. 1999 Apr;2(2):135-41. doi: 10.1016/S1369-5274(99)80024-1.
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.
抗σ因子可调节由替代σ因子控制的众多调控子的表达。抗σ因子自身受以下几种方式调控：从细胞分泌（如通过钩形基体输出FlgM）、被抗抗σ因子隔离（如磷酸化调节的伴侣切换模块），或与胞外蛋白或小分子效应物相互作用（如胞外功能σ因子的跨膜调节因子）。近期的重要进展包括对相反的σ/抗σ结合表面的遗传学描述；FlgM在全酶去稳定化中的意外作用以及发现FlgM的折叠与σ28结合相关；首个抗σ拮抗剂的结构测定；以及对枯草芽孢杆菌中两个复杂伴侣切换模块的详细剖析。
