PDF(Pubmed)
Abstract：
The basal structure of the bacterial flagellum includes a membrane embedded MS-ring (formed by multiple copies of FliF) and a cytoplasmic C-ring (composed of proteins FliG, FliM and FliN). The SRP-type GTPase FlhF is required for directing the initial flagellar protein FliF to the cell pole, but the mechanisms are unclear. Here, we show that FlhF anchors developing flagellar structures to the polar landmark protein HubP/FimV, thereby restricting their formation to the cell pole. Specifically, the GTPase domain of FlhF interacts with HubP, while a structured domain at the N-terminus of FlhF binds to FliG. FlhF-bound FliG subsequently engages with the MS-ring protein FliF. Thus, the interaction of FlhF with HubP and FliG recruits a FliF-FliG complex to the cell pole. In addition, the modulation of FlhF activity by the MinD-type ATPase FlhG controls the interaction of FliG with FliM-FliN, thereby regulating the progression of flagellar assembly at the pole.
摘要：
细菌鞭毛的基础结构包括膜嵌入的MS环（由多个FliF拷贝形成）和胞质C环（由蛋白质FliG组成，FliM和FliN）。SRP型GTPaseFlhF是将初始鞭毛蛋白FliF引导到细胞极点所必需的，但机制尚不清楚。这里,我们表明FlhF锚定发展鞭毛结构到极性标志蛋白HubP/FimV，从而将它们的形成限制在细胞极。具体来说,FlhF的GTP酶结构域与HubP相互作用，而FlhF的N-末端的结构化结构域与FliG结合。FlhF结合的FliG随后与MS环蛋白FliF接合。因此，FlhF与HubP和FliG的相互作用将FliF-FliG复合物募集到细胞极点。此外,通过MinD型ATPaseFlhG对FlhF活性的调节控制FliG与FliM-FliN的相互作用,从而调节杆上鞭毛组装的进程。
