Tubulin depolymerization may be an ancient biological motor
Tubulin depolymerization may be an ancient biological motor
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DOI：
10.1242/jcs.067611
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发表时间：
2010-10-15
影响因子：
4
通讯作者：
Grishchuk, Ekaterina L.
中科院分区：
文献类型：
--
作者：
McIntosh, J. Richard;Volkov, Vladimir;Grishchuk, Ekaterina L.
有丝分裂染色体的运动是复杂的，并且在物种间表现出相当大的差异。大量的证据支持这样的想法，微管依赖的马达酶有助于这种变化，是重要的纺锤体的形成和染色体分离的准确完成。然而，向纺锤体极行走的马达对于酵母中染色体的至少一些向极运动是不稳定的，这表明解聚纺锤体微管可以在体内产生有丝分裂力。与微管缩短相关的向外张开的微管蛋白原丝可能是这种力的起源，因为它们可以移动适当附着在微管壁上的物体。例如，一些与运动舞蹈相关的蛋白质可以将实验对象（如微球）与体外缩短的微管结合，使它们移动许多微米。在这里，我们回顾了最近的证据，这种现象，强调力的产生机制和不同的耦合策略。我们还考虑了微管蛋白样蛋白FtsZ的弯曲细丝，它在胞质分裂的位点形成环绕细菌的环。这些力生成系统之间的机械相似性表明，在真核细胞有丝分裂和FtsZ介导的环收缩细菌中的微管蛋白解聚之间存在深刻的系统发育关系。
The motions of mitotic chromosomes are complex and show considerable variety across species. A wealth of evidence supports the idea that microtubule-dependent motor enzymes contribute to this variation and are important both for spindle formation and for the accurate completion of chromosome segregation. Motors that walk towards the spindle pole are, however, dispensable for at least some poleward movements of chromosomes in yeasts, suggesting that depolymerizing spindle microtubules can generate mitotic forces in vivo. Tubulin protofilaments that flare outward in association with microtubule shortening may be the origin of such forces, because they can move objects that are appropriately attached to a microtubule wall. For example, some kinetochore-associated proteins can couple experimental objects, such as microspheres, to shortening microtubules in vitro, moving them over many micrometers. Here, we review recent evidence about such phenomena, highlighting the force-generation mechanisms and different coupling strategies. We also consider bending filaments of the tubulin-like protein FtsZ, which form rings girding bacteria at their sites of cytokinesis. Mechanical similarities between these force-generation systems suggest a deep phylogenetic relationship between tubulin depolymerization in eukaryotic mitosis and FtsZ-mediated ring contraction in bacteria.