Laboratory for Developmental Genomics, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan.
Genes Cells. 2010 Nov;15(11):1145-57. doi: 10.1111/j.1365-2443.2010.01451.x. Epub 2010 Oct 21.
Dynactin is a multisubunit protein complex required for the activity of cytoplasmic dynein. In Caenorhabditis elegans, although 10 of the 11 dynactin subunits were identified based on the sequence similarities to their orthologs, the p24/p22 subunit has not been detected in the genome. Here, we demonstrate that DNC-3 (W10G11.20) is the functional counterpart of the p24/p22 subunit in C. elegans. RNAi phenotypes and subcellular localization of DNC-3 in early C. elegans embryos were nearly identical to those of the known dynactin components. All other dynactin subunits were co-immunoprecipitated with DNC-3, indicating that DNC-3 is a core component of dynactin. Furthermore, the overall secondary structure of DNC-3 resembles to those of the mammalian and yeast p24/p22. We found that DNC-3 is required for the localization of the DNC-1/p150(Glued) and DNC-2/dynamitin, the two components of the projection arm of dynactin, to the nuclear envelope of meiotic nuclei in the adult gonad. Moreover, DNC-3 physically interacted with DNC-1 and DNC-2 and significantly enhanced the binding ability between DNC-1 and DNC-2 in vitro. These results suggest that DNC-3 is essential for the formation of the projection arm subcomplex of dynactin.
动力蛋白激活蛋白复合体是一种多亚基蛋白复合物，对于细胞质动力蛋白的活性是必需的。在秀丽隐杆线虫中，尽管根据与同源物的序列相似性鉴定了 11 个动力蛋白激活蛋白复合体的 10 个亚基，但在基因组中未检测到 p24/p22 亚基。在这里，我们证明 DNC-3（W10G11.20）是秀丽隐杆线虫中 p24/p22 亚基的功能对应物。早期秀丽隐杆线虫胚胎中的 DNC-3 的 RNAi 表型和亚细胞定位与已知的动力蛋白激活蛋白复合体成分几乎相同。所有其他动力蛋白激活蛋白复合体亚基都与 DNC-3 共免疫沉淀，表明 DNC-3 是动力蛋白激活蛋白复合体的核心组成部分。此外， DNC-3 的整体二级结构类似于哺乳动物和酵母的 p24/p22。我们发现 DNC-3 对于 DNC-1/p150(Glued)和 DNC-2/dynamitin （动力蛋白激活蛋白复合体投射臂的两个组成部分）向成体性腺减数分裂核的核膜的定位是必需的。此外， DNC-3 与 DNC-1 和 DNC-2 相互作用，并在体外显著增强了 DNC-1 和 DNC-2 之间的结合能力。这些结果表明 DNC-3 对于动力蛋白激活蛋白复合体投射臂亚基复合物的形成是必不可少的。
