Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauer Str. 108, 01307 Dresden, Germany.
Nat Cell Biol. 2013 Sep;15(9):1116-22. doi: 10.1038/ncb2834. Epub 2013 Aug 25.
Metaphase spindles are microtubule-based structures that use a multitude of proteins to modulate their morphology and function. Today, we understand many details of microtubule assembly, the role of microtubule-associated proteins, and the action of molecular motors. Ultimately, the challenge remains to understand how the collective behaviour of these nanometre-scale processes gives rise to a properly sized spindle on the micrometre scale. By systematically engineering the enzymatic activity of XMAP215, a processive microtubule polymerase, we show that Xenopus laevis spindle length increases linearly with microtubule growth velocity, whereas other parameters of spindle organization, such as microtubule density, lifetime and spindle shape, remain constant. We further show that mass balance can be used to link the global property of spindle size to individual microtubule dynamic parameters. We propose that spindle length is set by a balance of non-uniform nucleation and global microtubule disassembly in a liquid-crystal-like arrangement of microtubules.
有丝分裂纺锤体是基于微管的结构，利用多种蛋白质来调节其形态和功能。如今，我们已经了解了微管组装、微管相关蛋白的作用以及分子马达的作用的许多细节。最终的挑战仍然是要理解这些纳米级过程的集体行为如何在微米级尺度上产生适当大小的纺锤体。通过系统地工程化 XMAP215 的酶活性，一种连续的微管聚合酶，我们表明 Xenopus laevis 纺锤体的长度与微管生长速度呈线性增加，而纺锤体组织的其他参数，如微管密度、寿命和纺锤体形状保持不变。我们进一步表明，可以使用质量平衡将纺锤体大小的全局性质与单个微管动力学参数联系起来。我们提出，纺锤体的长度是通过在微管的液晶状排列中不均匀的成核和全局微管解聚之间的平衡来设定的。
