Structure of the fission yeast actomyosin ring during constriction.
Structure of the fission yeast actomyosin ring during constriction.
复制标题
收缩过程中裂变酵母肌动球蛋白环的结构。
DOI：
10.1073/pnas.1711218115
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发表时间：
2018
影响因子：
11.1
通讯作者：
Jensen,GrantJ
中科院分区：
文献类型：
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作者：
Swulius,MatthewT;Nguyen,LamT;Ladinsky,MarkS;Ortega,DaviR;Aich,Samya;Mishra,Mithilesh;Jensen,GrantJ
许多真核生物中的细胞分裂是由含有肌动蛋白和肌球蛋白的环驱动的。虽然人们对所涉及的主要蛋白质了解很多，但肌动蛋白丝在收缩机制内的精确排列以及力如何传递到膜上仍不清楚。在这里，我们使用冷冻切片和冷冻聚焦离子束铣削来获得裂殖酵母中冷冻保存的肌动球蛋白环，以便通过电子冷冻断层扫描进行直接 3D 成像。我们的结果表明，直的、重叠的肌动蛋白丝，彼此几乎平行且与膜平行，形成直径约150 nm的松散束，在分裂隔膜的前缘“支撑”向内弯曲的膜。细丝不与膜直接接触。我们对肌动蛋白丝的分析揭示了丝数、束内丝之间的最近邻距离、它们与膜的距离以及相对于膜的角度分布的变化。
Cell division in many eukaryotes is driven by a ring containing actin and myosin. While much is known about the main proteins involved, the precise arrangement of actin filaments within the contractile machinery, and how force is transmitted to the membrane, remains unclear. Here we use cryosectioning and cryofocused ion beam milling to gain access to cryopreserved actomyosin rings inSchizosaccharomyces pombefor direct 3D imaging by electron cryotomography. Our results show that straight, overlapping actin filaments, running nearly parallel to each other and to the membrane, form a loose bundle of ∼150 nm in diameter that “saddles” the inward-bending membrane at the leading edge of the division septum. The filaments do not make direct contact with the membrane. Our analysis of the actin filaments reveals the variability in filament number, nearest-neighbor distances between filaments within the bundle, their distance from the membrane, and angular distribution with respect to the membrane.