Pathology and Cell Biology, Columbia University, New York, NY.
Pathology and Cell Biology, Columbia University, New York, NY
J Cell Biol. 2018 Sep 3;217(9):3019-3029. doi: 10.1083/jcb.201707081. Epub 2018 Jun 21.
Cytoplasmic dynein is involved in diverse cell cycle-dependent functions regulated by several accessory factors, including Nde1 and Ndel1. Little is known about the role of these proteins in dynein cargo binding, and less is known about their cell cycle--dependent dynein regulation. Using Nde1 RNAi, mutant cDNAs, and a phosphorylation site-specific antibody, we found a specific association of phospho-Nde1 with the late G2-M nuclear envelope and prophase to anaphase kinetochores, comparable to the pattern for the Nde1 interactor CENP-F. Phosphomutant-Nde1 associated only with prometaphase kinetochores and showed weaker CENP-F binding in in vitro assays. Nde1 RNAi caused severe delays in mitotic progression, which were substantially rescued by both phosphomimetic and phosphomutant Nde1. Expression of a dynein-binding-deficient Nde1 mutant reduced kinetochore dynein by half, indicating a major role for Nde1 in kinetochore dynein recruitment. These results establish CENP-F as the first well-characterized Nde1 cargo protein, and reveal phosphorylation control of Nde1 cargo binding throughout a substantial fraction of the cell cycle.
细胞质动力蛋白参与多种细胞周期依赖性功能,受几种辅助因子调节,包括 Nde1 和 Ndel1。这些蛋白质在动力蛋白货物结合中的作用知之甚少,它们在细胞周期依赖性动力蛋白调节中的作用知之甚少。使用 Nde1 RNAi、突变 cDNA 和磷酸化位点特异性抗体,我们发现磷酸化 Nde1 与晚期 G2-M 核膜和前期到后期的动粒特异性结合,与 Nde1 相互作用因子 CENP-F 的模式相当。磷酸化突变 Nde1 仅与有丝分裂前期动粒结合,并且在体外测定中显示出与 CENP-F 的结合较弱。Nde1 RNAi 导致有丝分裂进程严重延迟,这在很大程度上可以通过磷酸模拟和磷酸突变 Nde1 得到挽救。表达动力蛋白结合缺陷的 Nde1 突变体使动粒动力蛋白减少一半,表明 Nde1 在动粒动力蛋白募集中起主要作用。这些结果确立了 CENP-F 作为第一个得到充分表征的 Nde1 货物蛋白,并揭示了 Nde1 货物结合在细胞周期的很大一部分中的磷酸化控制。