Ren Jinqi, Zhao Lingyan, Chen Guanghan, Ou Guangshuo, Feng Wei
State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
Nat Commun. 2025 Jul 24;16(1):6816. doi: 10.1038/s41467-025-62152-8.
Heterotrimeric kinesin-2, composed of two distinct kinesin motors and a kinesin-associated protein (KAP), is essential for intraflagellar transport and ciliogenesis. KAP specifically recognizes the hetero-paired motor tails for the holoenzyme assembly, but the underlying mechanism remains unclear. Here, we determine the structure of KAP-1 in complex with the hetero-paired tails from kinesin-2 motors KLP-20 and KLP-11. KAP-1 forms an elongated superhelical structure characterized by a central groove and a C-terminal helical (CTH)-hook. The two motor tails fold together and are co-recognized by the central groove of KAP-1. The adjacent hetero-pairing trigger sequences preceding the two tails form an intertwined heterodimer, which co-captures the CTH-hook of KAP-1 to complete the holoenzyme assembly. Mutations in the interfaces between KAP-1 and the two tails disrupt the heterotrimeric kinesin-2 complex and impair kinesin-2-mediated intraflagellar transport. Thus, KAP-1 and the hetero-paired motors are mutually co-recognized, ensuring the proper assembly of heterotrimeric kinesin-2 for cargo transport.
异源三聚体驱动蛋白-2由两种不同的驱动蛋白马达和一种驱动蛋白相关蛋白（KAP）组成，对鞭毛内运输和纤毛发生至关重要。KAP特异性识别异源配对的马达尾部以进行全酶组装，但其潜在机制仍不清楚。在这里，我们确定了KAP-1与来自驱动蛋白-2马达KLP-20和KLP-11的异源配对尾部形成的复合物的结构。KAP-1形成一种细长的超螺旋结构，其特征是有一个中央凹槽和一个C末端螺旋（CTH）钩。两条马达尾部折叠在一起，并被KAP-1的中央凹槽共同识别。两条尾部之前相邻的异源配对触发序列形成一个相互缠绕的异二聚体，该异二聚体共同捕获KAP-1的CTH钩以完成全酶组装。KAP-1与两条尾部之间界面处的突变会破坏异源三聚体驱动蛋白-2复合物，并损害驱动蛋白-2介导的鞭毛内运输。因此，KAP-1和异源配对的马达相互共同识别，确保异源三聚体驱动蛋白-2正确组装以进行货物运输。
