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, China.
Elife. 2020 Oct 28;9:e58868. doi: 10.7554/eLife.58868.
Heterodimeric motor organization of kinesin-II is essential for its function in anterograde IFT in ciliogenesis. However, the underlying mechanism is not well understood. In addition, the anterograde IFT velocity varies significantly in different organisms, but how this velocity affects ciliary length is not clear. We show that in motors are only stable as heterodimers in vivo, which is likely the key factor for the requirement of a heterodimer for IFT. Second, chimeric CrKinesin-II with human kinesin-II motor domains functioned in vitro and in vivo, leading to a ~ 2.8 fold reduced anterograde IFT velocity and a similar fold reduction in IFT injection rate that supposedly correlates with ciliary assembly activity. However, the ciliary length was only mildly reduced (~15%). Modeling analysis suggests a nonlinear scaling relationship between IFT velocity and ciliary length that can be accounted for by limitation of the motors and/or its ciliary cargoes, e.g. tubulin.
驱动蛋白-II 的异二聚体马达组织对于其在纤毛发生中的顺向 IFT 中的功能是必不可少的。然而，其潜在的机制还不是很清楚。此外，不同生物体中的顺向IFT 速度差异很大，但这种速度如何影响纤毛长度尚不清楚。我们表明，在体内只有异二聚体才是稳定的，这可能是异二聚体对IFT 的要求的关键因素。其次，带有人类驱动蛋白-II 马达结构域的嵌合 CrKinesin-II 在体外和体内都能发挥作用，导致顺向IFT 速度降低约 2.8 倍，IFT 注射率也降低了类似的倍数，这可能与纤毛组装活性相关。然而，纤毛长度仅轻度降低（约 15%）。建模分析表明，IFT 速度和纤毛长度之间存在非线性比例关系，这可以通过对马达及其纤毛货物（例如微管蛋白）的限制来解释。
