MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, China.
EMBO J. 2021 Mar 1;40(5):e105781. doi: 10.15252/embj.2020105781. Epub 2020 Dec 28.
The intraflagellar transport (IFT) machinery consists of the anterograde motor kinesin-II, the retrograde motor IFT dynein, and the IFT-A and -B complexes. However, the interaction among IFT motors and IFT complexes during IFT remains elusive. Here, we show that the IFT-B protein IFT54 interacts with both kinesin-II and IFT dynein and regulates anterograde IFT. Deletion of residues 342-356 of Chlamydomonas IFT54 resulted in diminished anterograde traffic of IFT and accumulation of IFT motors and complexes in the proximal region of cilia. IFT54 directly interacted with kinesin-II and this interaction was strengthened for the IFT54 mutant in vitro and in vivo. The deletion of residues 261-275 of IFT54 reduced ciliary entry and anterograde traffic of IFT dynein with accumulation of IFT complexes near the ciliary tip. IFT54 directly interacted with IFT dynein subunit D1bLIC, and deletion of residues 261-275 reduced this interaction. The interactions between IFT54 and the IFT motors were also observed in mammalian cells. Our data indicate a central role for IFT54 in binding the IFT motors during anterograde IFT.
内鞭毛运输（IFT）机制由正向运动的驱动蛋白-2（kinesin-II）、逆向运动的 IFT 动力蛋白 dynein、IFT-A 和 -B 复合物组成。然而，IFT 期间 IFT 马达和 IFT 复合物之间的相互作用仍难以捉摸。在这里，我们表明 IFT-B 蛋白 IFT54 与 kinesin-II 和 IFT 动力蛋白 dynein 相互作用，并调节正向 IFT。删除衣藻 IFT54 的 342-356 个残基导致 IFT 的正向运输减少，IFT 马达和复合物在纤毛的近端区域积累。IFT54 与 kinesin-II 直接相互作用，这种相互作用在体外和体内的 IFT54 突变体中得到增强。IFT54 的 261-275 个残基缺失减少了 IFT 动力蛋白的纤毛进入和正向运输，IFT 复合物在纤毛尖端附近积累。IFT54 与 IFT 动力蛋白亚基 D1bLIC 直接相互作用，而 261-275 个残基缺失减少了这种相互作用。IFT54 与 IFT 马达之间的相互作用也在哺乳动物细胞中观察到。我们的数据表明，IFT54 在正向 IFT 期间结合 IFT 马达中起着核心作用。
