Electron cryo-tomography provides insight into procentriole architecture and assembly mechanism
Electron cryo-tomography provides insight into procentriole architecture and assembly mechanism
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DOI：
10.1101/442590
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发表时间：
2018-10
期刊：
影响因子：
7.7
通讯作者：
Sam Li;José-Jesús Fernández;W. Marshall;D. Agard
中科院分区：
文献类型：
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作者：
Sam Li;José-Jesús Fernández;W. Marshall;D. Agard
中心粒是细胞过程中具有多种功能的重要结构。中心粒的生物发生和体内平衡受到严格调控。利用电子冷冻层析技术（cryoET）研究了莱茵衣藻原核的结构。我们发现了一组附着在三重微管（MT）上的非微管蛋白成分，其中许多位于可能加强三重微管的小管的连接处。我们描述了连接相邻三联体的A-C连接器的结构。我们发现POC1是A-C连接器的一个组成部分。其保守的WD40 β-螺旋桨结构域提供了与其他A-C连接元件连接的位点。A-C连接器的扭转导致三联体在前心孔的纵向上呈虹膜膜片状运动。最后，我们在原中心ole的生长端确定了两个组装中间体，使我们能够提出一个原中心ole组装的模型。我们的研究结果提供了一个全面的结构框架，以了解支持前核苷生物发生和组装的分子机制。
Centriole is an essential structure with multiple functions in cellular processes. Centriole biogenesis and homeostasis is tightly regulated. Using electron cryo-tomography (cryoET) we present the structure of procentrioles from Chlamydomonas reinhardtii. We identified a set of non-tubulin components attached to the triplet microtubule (MT), many are at the junctions of tubules likely to reinforce the triplet. We describe structure of the A-C linker that bridges neighboring triplets. We find that POC1 is an integral component of the A-C linker. Its conserved WD40 β-propeller domain provides sites for attachment to other A-C linker components. The twist of A-C linker results in an iris diaphragm-like motion of the triplets in the longitudinal direction of procentriole. Finally, we identified two assembly intermediates at the growing ends of procentriole allowing us to propose a model for the procentriole assembly. Our results provide a comprehensive structural framework for understanding the molecular mechanisms underpinning procentriole biogenesis and assembly.