Membrane binding controls ordered self-assembly of animal septins.
Membrane binding controls ordered self-assembly of animal septins.
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DOI：
10.7554/elife.63349
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发表时间：
2021-04-13
期刊：
影响因子：
7.7
通讯作者：
Koenderink GH
中科院分区：
文献类型：
--
作者：
Szuba A;Bano F;Castro-Linares G;Iv F;Mavrakis M;Richter RP;Bertin A;Koenderink GH
Septins是一种保守的细胞骨架蛋白，调节细胞皮质的机制。它们与质膜相互作用的机制尚不清楚。在这里，我们通过无细胞重组表明，结合到扁平脂膜上需要间隔素与阴离子脂类的静电相互作用，并促进苍蝇间隔素有序地自组装成丝状网。透射电子显微镜显示，苍蝇和哺乳动物的隔膜六角体都形成了单丝和双丝的阵列。原子力显微镜和石英晶体微天平表明，苍蝇细丝形成机械刚性的12至18纳米厚的双层隔膜。相比之下，C-末端截短的Septin突变体形成4 nm的单层，表明堆积需要DSep2和Put亚基上的C-末端卷曲的线圈。我们的工作表明，苍蝇隔膜结合是形成单丝和成对细丝有序阵列所必需的，并为隔膜调节细胞表面机制提供了新的见解。
Septins are conserved cytoskeletal proteins that regulate cell cortex mechanics. The mechanisms of their interactions with the plasma membrane remain poorly understood. Here, we show by cell-free reconstitution that binding to flat lipid membranes requires electrostatic interactions of septins with anionic lipids and promotes the ordered self-assembly of fly septins into filamentous meshworks. Transmission electron microscopy reveals that both fly and mammalian septin hexamers form arrays of single and paired filaments. Atomic force microscopy and quartz crystal microbalance demonstrate that the fly filaments form mechanically rigid, 12- to 18-nm thick, double layers of septins. By contrast, C-terminally truncated septin mutants form 4-nm thin monolayers, indicating that stacking requires the C-terminal coiled coils on DSep2 and Pnut subunits. Our work shows that membrane binding is required for fly septins to form ordered arrays of single and paired filaments and provides new insights into the mechanisms by which septins may regulate cell surface mechanics.