Microtubule structure by cryo-EM: snapshots of dynamic instability.
Microtubule structure by cryo-EM: snapshots of dynamic instability.
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DOI：
10.1042/ebc20180031
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发表时间：
2018-12-07
影响因子：
6.4
通讯作者：
Moores CA
中科院分区：
文献类型：
--
作者：
Manka SW;Moores CA
低温电子显微镜（cryo-EM）的发展使微管在其溶液样状态下被捕获，使数十年的洞察其动态机制和与结合伴侣的相互作用成为可能。Cryo-EM显微照片提供了微管的2D可视化，这些2D图像也可用于重建聚合物和任何相关结合伴侣的3D结构。以这种方式，结合位点的微管cytokeraton的许多组件，包括电机域从许多驱动蛋白电机，和微管结合域的动力蛋白电机和扩大收集微管相关蛋白已被确定。各种微管结合药物的作用也被研究。高分辨率cryo-EM结构也已被用于探测微管动态不稳定性的分子基础，由β-微管蛋白的GTdR活性驱动。这些研究表明，响应于微管蛋白GTTT循环中的步骤，晶格限制的微管蛋白二聚体的构象变化，最显著的是在纵向二聚体间界面的晶格压缩。虽然工作正在进行中，以确定一个完整的结构模型的动态不稳定性，注意力集中在微管蛋白原丝之间的横向接触，特别是在微管缝逐渐不稳定的作用。此外，较低分辨率的冷冻电子断层扫描三维结构揭示了微管末端的异质性以及它们的三维组织如何导致动态不稳定性。使用cryo-EM捕获的这些聚合物的快照将继续为它们的动力学，与细胞组分的相互作用以及微管在不同生理环境中对细胞功能的贡献提供重要见解。
The development of cryo-electron microscopy (cryo-EM) allowed microtubules to be captured in their solution-like state, enabling decades of insight into their dynamic mechanisms and interactions with binding partners. Cryo-EM micrographs provide 2D visualization of microtubules, and these 2D images can also be used to reconstruct the 3D structure of the polymer and any associated binding partners. In this way, the binding sites for numerous components of the microtubule cytoskeleton—including motor domains from many kinesin motors, and the microtubule-binding domains of dynein motors and an expanding collection of microtubule associated proteins—have been determined. The effects of various microtubule-binding drugs have also been studied. High-resolution cryo-EM structures have also been used to probe the molecular basis of microtubule dynamic instability, driven by the GTPase activity of β-tubulin. These studies have shown the conformational changes in lattice-confined tubulin dimers in response to steps in the tubulin GTPase cycle, most notably lattice compaction at the longitudinal inter-dimer interface. Although work is ongoing to define a complete structural model of dynamic instability, attention has focused on the role of gradual destabilization of lateral contacts between tubulin protofilaments, particularly at the microtubule seam. Furthermore, lower resolution cryo-electron tomography 3D structures are shedding light on the heterogeneity of microtubule ends and how their 3D organization contributes to dynamic instability. The snapshots of these polymers captured using cryo-EM will continue to provide critical insights into their dynamics, interactions with cellular components, and the way microtubules contribute to cellular functions in diverse physiological contexts.