The functional significance of microtubule quaternary structure

微管（MTs）是长而细长的α-β微管蛋白二聚体聚合物，形成有丝分裂纺锤体、轴突和细胞骨架。微管蛋白亚基头尾相连形成原丝（pfs），通常13个pfs横向相连形成MT。MT是“塑料”聚合物，也就是说微管蛋白可以形成不同的横向和纵向曲率结构。这种可塑性是由于微管蛋白二聚体之间连接的灵活性而成为可能，并可能赋予微管独特的机械性能。然而，在控制微管晶格的四级结构方面，结构可塑性对细胞构成了挑战。

Microtubules (MTs) are long, slender polymers of α-β tubulin dimers that form the mitotic spindle, axonemes, and the cytoskeleton. Tubulin subunits associate head-to-tail to form protofilaments (pfs), and typically 13 pfs are associated laterally to form the MT. MTs are "plastic" polymers, which is to say that tubulin can form structures that differ in their lateral and longitudinal curvature. This plasticity is made possible by flexibility in the links between tubulin dimers and may give microtubules their unique mechanical properties. Structural plasticity creates a challenge for cells, however, in terms of controlling the quaternary structure of the microtubule lattice.