Temporal control of bidirectional lipid-droplet motion in Drosophila depends on the ratio of kinesin-1 and its co-factor Halo
Temporal control of bidirectional lipid-droplet motion in Drosophila depends on the ratio of kinesin-1 and its co-factor Halo
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DOI：
10.1242/jcs.183426
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发表时间：
2016-04-01
影响因子：
4
通讯作者：
Welte, Michael A.
中科院分区：
文献类型：
--
作者：
Arora, Gurpreet K.;Tran, Susan L.;Welte, Michael A.
在双向运输过程中，单个货物沿着沿着微管轨道连续地来回移动，而货物群体总体上显示定向净运输。这种运输是如何在时间上受到控制的，还没有很好的理解。我们分析了这个问题的双向移动的脂滴在果蝇胚胎，一个系统中，净运输方向是发育控制。通过量化液滴分布如何随着胚胎发育而变化，我们表征了净液滴运输的时间转变，并确定了先前确定的，但表征不佳的交易调节剂Halo的关键贡献。特别是，我们发现，光环是瞬时表达的上升和下降的光环水平控制开关的全球分布。上升的光环等级必须在开始净加端传输之前通过一个阈值。该阈值水平取决于运动驱动蛋白-1的量：存在的驱动蛋白-1越多，在净加末端运输开始之前需要的Halo越多。由于Halo和驱动蛋白-1存在于共同的蛋白质复合物中，我们建议Halo作为驱动蛋白-1的限速辅助因子。
During bidirectional transport, individual cargoes move continuously back and forth along microtubule tracks, yet the cargo population overall displays directed net transport. How such transport is controlled temporally is not well understood. We analyzed this issue for bidirectionally moving lipid droplets in Drosophila embryos, a system in which net transport direction is developmentally controlled. By quantifying how the droplet distribution changes as embryos develop, we characterize temporal transitions in net droplet transport and identify the crucial contribution of the previously identified, but poorly characterized, transacting regulator Halo. In particular, we find that Halo is transiently expressed; rising and falling Halo levels control the switches in global distribution. Rising Halo levels have to pass a threshold before net plus-end transport is initiated. This threshold level depends on the amount of the motor kinesin-1: the more kinesin-1 is present, the more Halo is needed before net plus-end transport commences. Because Halo and kinesin-1 are present in common protein complexes, we propose that Halo acts as a rate-limiting co-factor of kinesin-1.