Subunit-dependent modulation of septin assembly: Budding yeast septin Shs1 promotes ring and gauze formation
Subunit-dependent modulation of septin assembly: Budding yeast septin Shs1 promotes ring and gauze formation
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DOI：
10.1083/jcb.201107123
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发表时间：
2011-12-12
影响因子：
7.8
通讯作者：
Nogales, Eva
中科院分区：
文献类型：
--
作者：
Garcia, Galo, III;Bertin, Aurelie;Nogales, Eva
隔膜蛋白是保守的三磷酸鸟苷结合细胞骨架蛋白，参与膜重塑。在芽殖酵母中，胞质分裂所必需的五种有丝分裂隔膜（Cdc3、Cdc10、Cdc11、Cdc12和Shs1）在芽生长期间从斑块转变为领状，领状在胞质分裂中分裂成两个环，并在下一个细胞周期之前分解。Cdc3，Cdc10，Cdc11和Cdc12形成一个非极性的八聚体棒与Cdc11在每个尖端，聚合成直的成对的细丝。我们发现，Shs1取代Cdc11，导致八聚体杆不成细丝，但横向关联，形成弯曲的束，关闭成环。在体内，一半的shs1 δ突变细胞表现出不完整的衣领和中断颈丝。重要的是，Shs1中不同的拟磷酸化突变可以阻止环的形成或促进纱布状网状结构的形成。这些结果表明，一个单一的替代终端亚基是足以赋予一个独特的高阶隔蛋白超微结构，可以进一步调节磷酸化。
Septins are conserved guanosine triphosphate-binding cytoskeletal proteins involved in membrane remodeling. In budding yeast, five mitotic septins (Cdc3, Cdc10, Cdc11, Cdc12, and Shs1), which are essential for cytokinesis, transition during bud growth from a patch to a collar, which splits into two rings in cytokinesis and is disassembled before the next cell cycle. Cdc3, Cdc10, Cdc11, and Cdc12 form an apolar octameric rod with Cdc11 at each tip, which polymerizes into straight paired filaments. We show that Shs1 substitutes for Cdc11, resulting in octameric rods that do not polymerize into filaments but associate laterally, forming curved bundles that close into rings. In vivo, half of shs1 Delta mutant cells exhibit incomplete collars and disrupted neck filaments. Importantly, different phosphomimetic mutations in Shs1 can either prevent ring formation or promote formation of a gauzelike meshwork. These results show that a single alternative terminal subunit is sufficient to confer a distinctive higher-order septin ultrastructure that can be further regulated by phosphorylation.