A microtubule bestiary: structural diversity in tubulin polymers.
A microtubule bestiary: structural diversity in tubulin polymers.
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DOI：
10.1091/mbc.e16-05-0271
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发表时间：
2017-11-01
影响因子：
3.3
通讯作者：
Brouhard GJ
中科院分区：
文献类型：
--
作者：
Chaaban S;Brouhard GJ
微管是在所有真核细胞中发现的αβ-微管蛋白的细长聚合物。微管蛋白纵向结合形成原丝，相邻的原丝横向结合形成微管。在教科书的观点中，微管1）由13根原丝组成，2）由中心体排列成放射状阵列，3）内置于9+2轴丝中。虽然这些典型的结构在真核生物中占主导地位，但在上个世纪，人们发现了具有不同原丝数量和高阶微管组装体的微管。在这里，我们调查这些非典型的结构，从4-原丝微管的Prosthecalyptus的40-原丝辅助微管的螳螂精子。本文综述了不同物种、同一物种内不同细胞以及同一细胞内不同阶段的原丝数目的变化。我们描述了原丝数量的决定因素，即成核因子，微管蛋白亚型，和翻译后修饰。最后，我们推测这些不同的聚合物的功能意义。配备了新的微管蛋白纯化工具，该领域现在准备解决长期存在的问题微管结构的进化基础。
Microtubules are long, slender polymers of αβ-tubulin found in all eukaryotic cells. Tubulins associate longitudinally to form protofilaments, and adjacent protofilaments associate laterally to form the microtubule. In the textbook view, microtubules are 1) composed of 13 protofilaments, 2) arranged in a radial array by the centrosome, and 3) built into the 9+2 axoneme. Although these canonical structures predominate in eukaryotes, microtubules with divergent protofilament numbers and higher-order microtubule assemblies have been discovered throughout the last century. Here we survey these noncanonical structures, from the 4-protofilament microtubules of Prosthecobacter to the 40-protofilament accessory microtubules of mantidfly sperm. We review the variety of protofilament numbers observed in different species, in different cells within the same species, and in different stages within the same cell. We describe the determinants of protofilament number, namely nucleation factors, tubulin isoforms, and posttranslational modifications. Finally, we speculate on the functional significance of these diverse polymers. Equipped with novel tubulin-purification tools, the field is now prepared to tackle the long-standing question of the evolutionary basis of microtubule structure.