Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, England.
INSERM UMR-S 839, 17 Rue du Fer à Moulin, 75005 Paris, France.
Acta Crystallogr D Struct Biol. 2018 Jun 1;74(Pt 6):572-584. doi: 10.1107/S2059798318001948. Epub 2018 Apr 11.
The microtubule cytoskeleton is involved in many vital cellular processes. Microtubules act as tracks for molecular motors, and their polymerization and depolymerization can be harnessed to generate force. The structures of microtubules provide key information about the mechanisms by which their cellular roles are accomplished and the physiological context in which these roles are performed. Cryo-electron microscopy allows the visualization of in vitro-polymerized microtubules and has provided important insights into their overall morphology and the influence of a range of factors on their structure and dynamics. Cryo-electron tomography can be used to determine the unique three-dimensional structure of individual microtubules and their ends. Here, a previous cryo-electron tomography study of in vitro-polymerized GMPCPP-stabilized microtubules is revisited, the findings are compared with new tomograms of dynamic in vitro and cellular microtubules, and the information that can be extracted from such data is highlighted. The analysis shows the surprising structural heterogeneity of in vitro-polymerized microtubules. Lattice defects can be observed both in vitro and in cells. The shared ultrastructural properties in these different populations emphasize the relevance of three-dimensional structures of in vitro microtubules for understanding microtubule cellular functions.
微管细胞骨架参与许多重要的细胞过程。微管充当分子马达的轨道，其聚合和解聚可以被利用来产生力。微管的结构提供了关于其细胞功能完成的机制以及这些功能执行的生理背景的关键信息。低温电子显微镜允许体外聚合的微管可视化，并为其整体形态以及一系列因素对其结构和动力学的影响提供了重要的见解。低温电子断层扫描可用于确定单个微管及其末端的独特三维结构。在这里，重新回顾了之前关于体外聚合 GMPCPP 稳定微管的低温电子断层扫描研究，将研究结果与动态体外和细胞微管的新断层扫描进行了比较，并强调了可以从这些数据中提取的信息。分析表明，体外聚合的微管具有惊人的结构异质性。可以在体外和细胞中观察到晶格缺陷。这些不同群体中共同的超微结构特性强调了体外微管的三维结构对于理解微管细胞功能的相关性。
