Physics Department, University of California, Berkeley, CA, 94709, USA.
Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94709, USA.
Nat Commun. 2023 Nov 9;14(1):7221. doi: 10.1038/s41467-023-42907-x.
Cytoplasmic dynein drives the motility and force generation functions towards the microtubule minus end. The assembly of dynein with dynactin and a cargo adaptor in an active transport complex is facilitated by Lis1 and Nde1/Ndel1. Recent studies proposed that Lis1 relieves dynein from its autoinhibited conformation, but the physiological function of Nde1/Ndel1 remains elusive. Here, we investigate how human Nde1 and Lis1 regulate the assembly and subsequent motility of mammalian dynein using in vitro reconstitution and single molecule imaging. We find that Nde1 recruits Lis1 to autoinhibited dynein and promotes Lis1-mediated assembly of dynein-dynactin adaptor complexes. Nde1 can compete with the α2 subunit of platelet activator factor acetylhydrolase 1B (PAF-AH1B) for the binding of Lis1, which suggests that Nde1 may disrupt PAF-AH1B recruitment of Lis1 as a noncatalytic subunit, thus promoting Lis1 binding to dynein. Before the initiation of motility, the association of dynactin with dynein triggers the dissociation of Nde1 from dynein by competing against Nde1 binding to the dynein intermediate chain. Our results provide a mechanistic explanation for how Nde1 and Lis1 synergistically activate the dynein transport machinery.
细胞质动力蛋白驱动向微管负端的运动和力产生功能。动力蛋白与动力蛋白和货物衔接器在主动运输复合物中的组装由 Lis1 和 Nde1/Ndel1 促进。最近的研究提出 Lis1 将动力蛋白从其自身抑制构象中释放出来，但 Nde1/Ndel1 的生理功能仍不清楚。在这里，我们使用体外重组和单分子成像研究了人 Nde1 和 Lis1 如何调节哺乳动物动力蛋白的组装和随后的运动。我们发现 Nde1 将 Lis1 招募到自动抑制的动力蛋白上，并促进 Lis1 介导的动力蛋白-动力蛋白衔接器复合物的组装。Nde1 可以与血小板激活因子乙酰水解酶 1B（PAF-AH1B）的α2 亚基竞争 Lis1 的结合，这表明 Nde1 可能作为非催化亚基破坏 PAF-AH1B 对 Lis1 的招募，从而促进 Lis1 与动力蛋白的结合。在运动开始之前，动力蛋白与衔接蛋白的结合通过与动力蛋白中间链的结合竞争来触发 Nde1 从动力蛋白上的解离。我们的结果为 Nde1 和 Lis1 如何协同激活动力蛋白运输机制提供了机制解释。
