NOCA-1 functions with γ-tubulin and in parallel to Patronin to assemble non-centrosomal microtubule arrays in C. elegans.
NOCA-1 functions with γ-tubulin and in parallel to Patronin to assemble non-centrosomal microtubule arrays in C. elegans.
复制标题
DOI：
10.7554/elife.08649
复制
发表时间：
2015-09-15
期刊：
影响因子：
7.7
通讯作者：
Oegema K
中科院分区：
文献类型：
--
作者：
Wang S;Wu D;Quintin S;Green RA;Cheerambathur DK;Ochoa SD;Desai A;Oegema K
非中心体微管阵列在分化的组织中组装以执行机械和基于运输的功能。在这项研究中，我们鉴定出秀丽隐杆线虫 NOCA-1 是一种与脊椎动物 ninein 同源的蛋白质。 NOCA-1 有助于多种组织中非中心体微管阵列的组装。在幼虫表皮中，NOCA-1 与负端保护因子 Patronin/PTRN-1 一起发挥冗余作用，组装蠕虫生长和形态发生所必需的圆周微管阵列。该组织中 γ-微管蛋白复合物亚基的受控降解表明，γ-微管蛋白与 NOCA-1 的作用与 Patronin/PTRN-1 平行。在种系中，NOCA-1 和 γ-微管蛋白共定位于细胞表面，抑制其中任何一个都会导致微管组装缺陷。 γ-微管蛋白的靶向独立于 NOCA-1，但当非必需的推定棕榈酰化半胱氨酸发生突变时，NOCA-1 靶向需要 γ-微管蛋白。这些结果表明，NOCA-1 与 γ-微管蛋白一起作用，在多个组织中组装非中心体阵列，并突出了 ninein 和 Patronin 蛋白家族之间的功能重叠。 DOI：http://dx.doi.org/10.7554/eLife.08649.001 微管是在动物和其他真核生物细胞中发现的中空刚性丝。这些细丝由称为微管蛋白异二聚体的较小结构单元构建而成。在分裂的动物细胞中，它们主要从称为中心体的结构中产生。当细胞分裂时，源自中心体的微管阵列有助于组装分离染色体的纺锤状结构。许多非分裂或特化细胞——包括神经元、皮肤细胞和肌肉纤维——组装其他微管阵列，这些微管阵列不是从中心体产生的，但仍然发挥着各种结构、机械和运输作用。与中心体阵列相比，人们对这些非中心体微管如何组装的了解要少得多。一种名为“ninein”的脊椎动物蛋白此前已被证明参与中心体微管的锚定。 Ninein 可以改变其在哺乳动物皮肤细胞中从中心体到细胞表面的定位，这表明它也可能在组装这些细胞中发现的外周微管阵列中发挥作用。现在，王等人。已经从蠕虫中鉴定出一种名为 NOCA-1 的蛋白质，该蛋白质包含一个与 Ninein 部分相似的区域，之前已证明该区域是将微管锚定在中心体上所必需的。实验表明，NOCA-1 指导秀丽隐杆线虫多个组织中非中心体微管阵列的组装。这包括蠕虫幼虫的外层，类似于哺乳动物的皮肤。结果还强调，NOCA-1 与称为 PTRN-1 的 Patronin 蛋白质家族成员具有许多相同的作用，PTRN-1 与微管的“负”端相互作用，以防止微管破裂。王等人。还发现 NOCA-1 与另一种称为 γ-微管蛋白的蛋白质一起作用，γ-微管蛋白有助于新微管的形成，并与微管负端相互作用。相反，PTRN-1 独立于 γ-微管蛋白发挥作用。这表明 NOCA-1 与 γ-微管蛋白一起保护新的微管末端或促进其组装，其作用类似于守护蛋白家族蛋白的作用。总体而言，Wang 等人的结果强调了 ninein 相关蛋白在非中心体微管阵列组装中的重要性，并表明 ninein 和 Patronin 蛋白家族的重叠作用。 DOI：http://dx.doi.org/10.7554/eLife.08649.002
Non-centrosomal microtubule arrays assemble in differentiated tissues to perform mechanical and transport-based functions. In this study, we identify Caenorhabditis elegans NOCA-1 as a protein with homology to vertebrate ninein. NOCA-1 contributes to the assembly of non-centrosomal microtubule arrays in multiple tissues. In the larval epidermis, NOCA-1 functions redundantly with the minus end protection factor Patronin/PTRN-1 to assemble a circumferential microtubule array essential for worm growth and morphogenesis. Controlled degradation of a γ-tubulin complex subunit in this tissue revealed that γ-tubulin acts with NOCA-1 in parallel to Patronin/PTRN-1. In the germline, NOCA-1 and γ-tubulin co-localize at the cell surface, and inhibiting either leads to a microtubule assembly defect. γ-tubulin targets independently of NOCA-1, but NOCA-1 targeting requires γ-tubulin when a non-essential putatively palmitoylated cysteine is mutated. These results show that NOCA-1 acts with γ-tubulin to assemble non-centrosomal arrays in multiple tissues and highlight functional overlap between the ninein and Patronin protein families. DOI: http://dx.doi.org/10.7554/eLife.08649.001 Microtubules are hollow, rigid filaments that are found in the cells of animals and other eukaryotes. These filaments are built from smaller building blocks called tubulin heterodimers; and in dividing animal cells, they mainly emerge from structures called centrosomes. When a cell is dividing, arrays of microtubules that originate from centrosomes help assemble the spindle-like structure that segregates the chromosomes. Many non-dividing or specialized cells—including neurons, skin cells and muscle fibers—assemble other arrays of microtubules that do not emerge from centrosomes, but nevertheless perform a variety of structural, mechanical and transport-based roles. Compared to the centrosomal arrays, much less is known about how these non-centrosomal microtubules are assembled. A vertebrate protein called ‘ninein’ had previously been shown to be involved in anchoring microtubules at centrosomes. Ninein can change its localization from centrosomes to the cell surface in mammalian skin cells, suggesting that it might also have a role in assembling the peripheral microtubule arrays that are found in these cells. Now, Wang et al. have identified a protein from worms called NOCA-1, which contains a region similar to the part of ninein that was previously shown to be needed to anchor microtubules at centrosomes. The experiments show that NOCA-1 guides the assembly of non-centrosomal microtubule arrays in multiple tissues in C. elegans worms. This includes in the outer layer of the worm's larvae, which is similar to mammalian skin. The results also highlight that NOCA-1 performs many of the same roles as a member of the Patronin family of proteins called PTRN-1, which interacts with the ‘minus’ end of a microtubule to prevent the microtubule from breaking apart. Wang et al. also found that NOCA-1 works with another protein called γ-tubulin, which helps new microtubules to form and also interacts with microtubule minus ends. In contrast, PTRN-1 works independently of γ-tubulin. This suggests that NOCA-1 works together with γ-tubulin to protect new microtubule ends or promote their assembly, a role similar to what has been proposed for Patronin family proteins. Overall, Wang et al.'s results highlight the importance of ninein-related proteins in the assembly of non-centrosomal microtubule arrays and suggest overlapping roles for the ninein and Patronin families of proteins. DOI: http://dx.doi.org/10.7554/eLife.08649.002