Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
J Cell Sci. 2023 Mar 1;136(5). doi: 10.1242/jcs.259257. Epub 2022 May 17.
Primary cilia are microtubule-based sensory organelles whose assembly and function rely on the conserved bidirectional intraflagellar transport (IFT) system, which is powered by anterograde kinesin-2 and retrograde cytoplasmic dynein-2 motors. Nematodes additionally employ a cell-type-specific kinesin-3 motor, KLP-6, which moves within cilia independently of IFT and regulates ciliary content and function. Here, we provide evidence that a KLP-6 homolog, KIF13B, undergoes bursts of bidirectional movement within primary cilia of cultured immortalized human retinal pigment epithelial (hTERT-RPE1) cells. Anterograde and retrograde intraciliary velocities of KIF13B were similar to those of IFT (as assayed using IFT172-eGFP), but intraciliary movement of KIF13B required its own motor domain and appeared to be cell-type specific. Our work provides the first demonstration of motor-driven, intraciliary movement by a vertebrate kinesin other than kinesin-2 motors.
原发性纤毛是微管基感觉细胞器，其组装和功能依赖于保守的双向鞭毛内运输（IFT）系统，该系统由正向驱动蛋白-2 和反向细胞质动力蛋白-2 马达提供动力。线虫还利用一种细胞类型特异性的驱动蛋白-3 马达，KLP-6，它在纤毛内独立于 IFT 移动，并调节纤毛内容和功能。在这里，我们提供的证据表明，KLP-6 同源物 KIF13B 在培养的永生化人视网膜色素上皮（hTERT-RPE1）细胞的初级纤毛内经历双向运动的爆发。KIF13B 的正向和反向纤毛内速度与 IFT 相似（如使用 IFT172-eGFP 测定），但 KIF13B 的纤毛内运动需要其自身的马达结构域，并且似乎是细胞类型特异性的。我们的工作首次证明了除了驱动蛋白-2 马达之外，脊椎动物驱动蛋白的马达驱动的、纤毛内运动。
