Critical Roles of a RhoGEF-Anillin Module in Septin Architectural Remodeling during Cytokinesis
Critical Roles of a RhoGEF-Anillin Module in Septin Architectural Remodeling during Cytokinesis
复制标题
DOI：
10.1016/j.cub.2020.02.023
复制
发表时间：
2020-04-20
期刊：
影响因子：
9.2
通讯作者：
Bi, Erfei
中科院分区：
文献类型：
--
作者：
Chen, Xi;Wang, Kangji;Bi, Erfei
在真菌和动物细胞的胞质分裂过程中，septin结构如何从沙漏形重塑为双环形仍然是未知的。在这里，我们表明，在沙漏到双环的过渡在芽殖酵母，septins收购“地带性结构”，其中成对的septin丝，组织沿着母芽轴与圆周单septin丝，Rho鸟嘌呤核苷酸交换因子（RhoGEF）Bud 3，和苯胺样蛋白Bud 4专门在外部区域和肌球蛋白-II丝在中间区域。Bud 3或其Bud 4相互作用结构域的缺失，但不是其RhoGEF结构域，导致单丝的完全丧失，而Bud 4或其Bud 3相互作用结构域的缺失使过渡沙漏不稳定，特别是在母亲侧，两种细丝类型的部分丧失。Bud 3和Bud 4的缺失进一步削弱了过渡结构，消除了双环的形成，同时在肌动球蛋白环收缩中没有引起明显的缺陷。这一分析和进一步的分析表明，Bud 3稳定的单丝，而Bud 4加强之间的相互作用的成对和单丝之间的过渡沙漏的外部区域，以及在双环。这项研究揭示了一个惊人的过渡沙漏，预模式两个细胞动力学结构-隔蛋白双环和肌动球蛋白环的带状架构，也定义了RhoGEF-苯胺模块在胞质分裂过程中在丝水平的隔蛋白结构重塑的重要作用。
How septin architecture is remodeled from an hourglass to a double ring during cytokinesis in fungal and animal cells remains unknown. Here, we show that during the hourglass-to-double-ring transition in budding yeast, septins acquire a "zonal architecture'' in which paired septin filaments that are organized along the mother-bud axis associate with circumferential single septin filaments, the Rho guanine-nucleotide-exchange factor (RhoGEF) Bud3, and the anillin-like protein Bud4 exclusively at the outer zones and with myosin-II filaments in the middle zone. Deletion of Bud3 or its Bud4-interacting domain, but not its RhoGEF domain, leads to a complete loss of the single filaments, whereas deletion of Bud4 or its Bud3-interacting domain destabilizes the transitional hourglass, especially at the mother side, with partial loss of both filament types. Deletion of Bud3 and Bud4 together further weakens the transitional structure and abolishes the double ring formation while causing no obvious defect in actomyosin ring constriction. This and further analyses suggest that Bud3 stabilizes the single filaments, whereas Bud4 strengthens the interaction between the paired and single filaments at the outer zones of the transitional hourglass, as well as in the double ring. This study reveals a striking zonal architecture for the transitional hourglass that pre-patterns two cytokinetic structures-a septin double ring and an actomyosin ring-and also defines the essential roles of a RhoGEF-anillin module in septin architectural remodeling during cytokinesis at the filament level.