Yang Jun, Zhao Yuanchang, Chai Pengxin, Yildiz Ahmet, Zhang Kai
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
Physics Department, University of California, Berkeley, Berkeley, CA, USA.
Nat Chem Biol. 2025 Aug 1. doi: 10.1038/s41589-025-01981-6.
Cytoplasmic dynein 1 (dynein) is the primary motor responsible for the retrograde transport of intracellular cargoes along microtubules. Activation of dynein requires the opening its autoinhibited Phi conformation, a process driven by Lis1 and Nde1/Ndel1. Using biochemical reconstitution and cryo-electron microscopy, we demonstrate that Nde1 enhances Lis1 binding to autoinhibited dynein and facilitates Phi opening. We identify a key intermediate in this activation pathway where a single Lis1 dimer binds between Phi-like (Phi) motor rings. In this 'Phi-Lis1' complex, Lis1 interacts with one motor domain through canonical sites at the AAA+ (adenosine triphosphatases associated with diverse cellular activities) ring and stalk, and with AAA5, AAA6 and linker regions of the other motor domain. Mutagenesis and motility assays confirm the critical role of the Phi-Lis1 interface in dynein activation. This intermediate forms rapidly in the presence of Nde1, although Nde1 is not part of Phi-Lis1. These findings provide key insights into how Nde1 promotes Lis1-mediated Phi opening.
胞质动力蛋白1（动力蛋白）是负责细胞内货物沿微管逆行运输的主要动力蛋白。动力蛋白的激活需要打开其自身抑制的Phi构象，这一过程由Lis1和Nde1/Ndel1驱动。通过生化重组和冷冻电子显微镜技术，我们证明Nde1增强了Lis1与自身抑制的动力蛋白的结合，并促进Phi构象的打开。我们在这一激活途径中鉴定出一个关键中间体，其中单个Lis1二聚体结合在类Phi（Phi）马达环之间。在这个“Phi-Lis1”复合物中，Lis1通过与多种细胞活动相关的腺苷三磷酸酶（AAA+）环和柄部的经典位点与一个马达结构域相互作用，并与另一个马达结构域的AAA5、AAA6和连接区相互作用。诱变和运动分析证实了Phi-Lis1界面在动力蛋白激活中的关键作用。尽管Nde1不是Phi-Lis1的一部分，但在Nde1存在的情况下，这个中间体迅速形成。这些发现为Nde1如何促进Lis1介导的Phi构象打开提供了关键见解。
