Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA.
Bioessays. 2019 Mar;41(3):e1800194. doi: 10.1002/bies.201800194. Epub 2019 Feb 7.
Microtubules form a highly dynamic filament network in all eukaryotic cells. Individual microtubules grow by tubulin dimer subunit addition and frequently switch between phases of growth and shortening. These unique dynamics are powered by GTP hydrolysis and drive microtubule network remodeling, which is central to eukaryotic cell biology and morphogenesis. Yet, our knowledge of the molecular events at growing microtubule ends remains incomplete. Here, recent ultrastructural, biochemical and cell biological data are integrated to develop a realistic model of growing microtubule ends comprised of structurally distinct but biochemically overlapping zones. Proteins that recognize microtubule lattice conformations associated with specific tubulin guanosine nucleotide states may independently control major structural transitions at growing microtubule ends. A model is proposed in which tubulin dimer addition and subsequent closure of the MT wall are optimized in cells to achieve rapid physiological microtubule growth.
微管在所有真核细胞中形成高度动态的丝状网络。单个微管通过微管蛋白二聚体亚基的添加而生长，并经常在生长和缩短的阶段之间切换。这些独特的动力学由 GTP 水解提供动力，并驱动微管网络重塑，这是真核细胞生物学和形态发生的核心。然而，我们对生长中的微管末端的分子事件的了解仍然不完整。在这里，最近的超微结构、生化和细胞生物学数据被整合在一起，以开发一个由结构上不同但生化上重叠的区域组成的生长中的微管末端的现实模型。识别与特定微管蛋白鸟嘌呤核苷酸状态相关的微管晶格构象的蛋白质可以独立地控制生长中的微管末端的主要结构转变。提出了一个模型，其中微管蛋白二聚体的添加和随后 MT 壁的闭合在细胞中被优化，以实现快速的生理微管生长。
