Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
PLoS One. 2013 Sep 30;8(9):e76081. doi: 10.1371/journal.pone.0076081. eCollection 2013.
Kinesin motors drive the long-distance anterograde transport of cellular components along microtubule tracks. Kinesin-dependent transport plays a critical role in neurogenesis and neuronal function due to the large distance separating the soma and nerve terminal. The fate of kinesin motors after delivery of their cargoes is unknown but has been postulated to involve degradation at the nerve terminal, recycling via retrograde motors, and/or recycling via diffusion. We set out to test these models concerning the fate of kinesin-1 motors after completion of transport in neuronal cells. We find that kinesin-1 motors are neither degraded nor returned by retrograde motors. By combining mathematical modeling and experimental analysis, we propose a model in which the distribution and recycling of kinesin-1 motors fits a "loose bucket brigade" where individual motors alter between periods of active transport and free diffusion within neuronal processes. These results suggest that individual kinesin-1 motors are utilized for multiple rounds of transport.
驱动蛋白沿着微管轨道驱动细胞成分的长距离正向运输。由于胞体和神经末梢之间的距离很大，驱动蛋白依赖性运输在神经发生和神经元功能中起着至关重要的作用。货物运输完成后，驱动蛋白的命运尚不清楚，但据推测涉及到在神经末梢降解、通过逆行马达回收，和/或通过扩散回收。我们着手测试这些模型，以了解神经元细胞中运输完成后驱动蛋白-1 马达的命运。我们发现驱动蛋白-1 马达既不会降解，也不会被逆行马达回收。通过结合数学建模和实验分析，我们提出了一个模型，其中驱动蛋白-1 马达的分布和回收符合“松散桶式接力”，即单个马达在神经元过程中的主动运输和自由扩散之间交替。这些结果表明，单个驱动蛋白-1 马达可用于多次运输。
