GTP-dependent formation of straight tubulin oligomers leads to microtubule nucleation.
GTP-dependent formation of straight tubulin oligomers leads to microtubule nucleation.
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DOI：
10.1083/jcb.202007033
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发表时间：
2021-04-05
期刊：
影响因子：
--
通讯作者：
Muto E
中科院分区：
文献类型：
--
作者：
Ayukawa R;Iwata S;Imai H;Kamimura S;Hayashi M;Ngo KX;Minoura I;Uchimura S;Makino T;Shirouzu M;Shigematsu H;Sekimoto K;Gigant B;Muto E
Ayukawa、岩田、今井等人通过使用快速冲洗负染电子显微镜观察微管自发成核途径中的早期中间体。这项研究表明，形成的直微管蛋白低聚物的临界尺寸是必不可少的成核。微管的成核是细胞活动的基本过程，但其机制尚不清楚，因为在微管聚合的早期阶段很难捕捉到罕见的随机事件。在这里，结合快速冲洗负染色电子显微镜（EM）和动力学分析，我们表明，形成直的低聚物的临界尺寸是必不可少的成核。GDP和GTP微管蛋白都形成具有广泛曲率范围的单链低聚物，但在成核后，GTP低聚物的曲率分布发生变化，产生少量直链低聚物。在β亚基中具有Y222F突变的微管蛋白的情况下，直链寡聚体的比例增加并且成核加速。我们的研究结果支持一个模型，其中GTP结合产生一个较小的人口直低聚物兼容的横向协会和进一步增长的MT。这项研究表明，参与成核的细胞因子通过稳定直链低聚物来促进成核。
Ayukawa, Iwata, Imai, et al. visualize the early intermediates in the pathway of spontaneous nucleation of microtubules by using rapid flush negative stain electron microscopy. This study demonstrates that the formation of straight tubulin oligomers of critical size is essential for nucleation. Nucleation of microtubules (MTs) is essential for cellular activities, but its mechanism is unknown because of the difficulty involved in capturing rare stochastic events in the early stage of polymerization. Here, combining rapid flush negative stain electron microscopy (EM) and kinetic analysis, we demonstrate that the formation of straight oligomers of critical size is essential for nucleation. Both GDP and GTP tubulin form single-stranded oligomers with a broad range of curvatures, but upon nucleation, the curvature distribution of GTP oligomers is shifted to produce a minor population of straight oligomers. With tubulin having the Y222F mutation in the β subunit, the proportion of straight oligomers increases and nucleation accelerates. Our results support a model in which GTP binding generates a minor population of straight oligomers compatible with lateral association and further growth to MTs. This study suggests that cellular factors involved in nucleation promote it via stabilization of straight oligomers.
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影响因子：
3.3
作者：
HYMAN, AA;SALSER, S;MITCHISON, TJ
通讯作者：
MITCHISON, TJ
直接观察显示沿微管运动的细胞质动力蛋白电动机内的叠加和大规模柔韧性。
影响因子：
16.6
作者：
Imai H;Shima T;Sutoh K;Walker ML;Knight PJ;Kon T;Burgess SA
通讯作者：
Burgess SA
影响因子：
2.9
作者：
DIAZ, JF;ANDREU, JM
通讯作者：
ANDREU, JM
影响因子：
64.5
作者：
Gardner MK;Charlebois BD;Jánosi IM;Howard J;Hunt AJ;Odde DJ
通讯作者：
Odde DJ
影响因子：
5.6
作者：
JOHNSON, KA;BORISY, GG
通讯作者：
BORISY, GG