Joshi H C
Department of Anatomy and Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322.
Bioessays. 1993 Oct;15(10):637-43. doi: 10.1002/bies.950151002.
In eukaryotic cells a specialized organelle called the microtubule organizing center (MTOC) is responsible for disposition of microtubules in a radial, polarized array in interphase cells and in the spindle in mitotic cells. Eukaryotic cells across different species, and different cell types within single species, have morphologically diverse MTOCs, but these share a common function of organizing microtubule arrays. MTOCs effect microtubule organization by initiating microtubule assembly and anchoring microtubules by their slowly growing minus ends, thus ensuring that the rapidly growing plus ends extend distally in each microtubule array. The goal is to define molecular components of the MTOC responsible for regulating microtubule assembly. One approach to defining the molecules responsible for MTOC function is to look for molecules common to all MTOCs. A newly discovered centrosomal protein, gamma-tubulin, is found in MTOCs in cells from many different organisms, and has several properties which make it a candidate for both initiation of microtubule assembly and anchorage. The hypothesis that gamma-tubulin plays a role in MTOCs in microtubule initiation and anchorage is currently being tested by a variety of experimental approaches.
在真核细胞中，一种名为微管组织中心（MTOC）的特殊细胞器负责在间期细胞中将微管排列成放射状、极化阵列，并在有丝分裂细胞的纺锤体中进行排列。不同物种的真核细胞以及单一物种内的不同细胞类型，其MTOC在形态上各不相同，但它们都具有组织微管阵列的共同功能。MTOC通过启动微管组装并以其缓慢生长的负极锚定微管来影响微管组织，从而确保快速生长的正极在每个微管阵列中向远端延伸。目标是确定负责调节微管组装的MTOC的分子成分。定义负责MTOC功能的分子的一种方法是寻找所有MTOC共有的分子。一种新发现的中心体蛋白γ-微管蛋白，在许多不同生物体的细胞的MTOC中都有发现，并且具有几种特性，使其成为微管组装起始和锚定的候选者。γ-微管蛋白在MTOC中参与微管起始和锚定的假说目前正在通过各种实验方法进行验证。
