Functional exploration of heterotrimeric kinesin-II in IFT and ciliary length control in Chlamydomonas.
Functional exploration of heterotrimeric kinesin-II in IFT and ciliary length control in Chlamydomonas.
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作者：
Li S;Wan KY;Chen W;Tao H;Liang X;Pan J
驱动蛋白-II的异二聚体运动组织是其在纤毛发生中的顺行IFT功能所必需的。然而，其基本机制尚未得到很好的理解。此外，在不同的生物体中，顺行IFT速度有显著差异，但该速度如何影响睫状体长度尚不清楚。我们发现，在衣原体马达是唯一稳定的异源二聚体在体内，这可能是一个异源二聚体IFT的要求的关键因素。第二，嵌合CrKinesin-II与人驱动蛋白-II运动域在体外和体内发挥作用，导致顺行IFT速度降低约2.8倍，IFT注射速率降低相似的倍数，推测与纤毛组装活性相关。然而，睫状体长度仅轻度减少（~15%）。建模分析表明，IFT速度和纤毛长度之间的非线性比例关系，可以通过限制电机和/或其纤毛货物，例如微管蛋白。
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 Chlamydomonas 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.