Lee Hye Seon, Yu Daseuli, Baek Kyoung Eun, Shin Ho-Chul, Kim Seung Jun, Do Heo Won, Ku Bonsu
Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Korea.
Life Science Research Institute, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea.
EMBO Rep. 2025 May 1. doi: 10.1038/s44319-025-00458-w.
Microtubule-associated cargo transport, a central process governing the localization and movement of various cellular cargoes, is orchestrated by the coordination of two types of motor proteins (kinesins and dyneins), along with diverse adaptor and accessory proteins. Hook microtubule tethering protein 3 (Hook3) is a cargo adaptor that serves as a scaffold for recruiting kinesin family member 1C (KIF1C) and dynein, thereby regulating bidirectional cargo transport. Herein, we conduct structural and functional analyses of how Hook3 mediates KIF1C-dependent anterograde cargo transport through interaction with KIF1C and PTPN21. We verify the interactions among the three proteins and determine the crystal structure of the Hook3(553-624) - KIF1C(714-809) complex. Subsequent structure-based mutational analysis demonstrates that this complex formation is necessary and sufficient for the interaction between the full-length proteins in HEK293T cells and plays a key role in Hook3- and KIF1C-mediated anterograde transport in RPE1 cells. Thus, this study provides a basis for a comprehensive understanding of how Hook3 cooperates with other components during the initial steps of activation and assembly of the Hook3- and KIF1C-dependent cargo transport machinery.
微管相关的货物运输是一个控制各种细胞货物定位和移动的核心过程，由两种类型的运动蛋白（驱动蛋白和动力蛋白）以及多种衔接蛋白和辅助蛋白的协调作用精心安排。钩状微管拴系蛋白3（Hook3）是一种货物衔接蛋白，作为招募驱动蛋白家族成员1C（KIF1C）和动力蛋白的支架，从而调节双向货物运输。在此，我们对Hook3如何通过与KIF1C和PTPN21相互作用介导依赖KIF1C的顺行货物运输进行了结构和功能分析。我们验证了这三种蛋白质之间的相互作用，并确定了Hook3(553 - 624) - KIF1C(714 - 809)复合物的晶体结构。随后基于结构的突变分析表明，这种复合物的形成对于HEK293T细胞中全长蛋白质之间的相互作用是必要且充分的，并且在RPE1细胞中Hook3和KIF1C介导的顺行运输中起关键作用。因此，本研究为全面理解Hook3在依赖Hook3和KIF1C的货物运输机制的激活和组装初始步骤中如何与其他成分协同作用提供了基础。
