Myosin V and Kinesin act as tethers to enhance each others' processivity
Myosin V and Kinesin act as tethers to enhance each others' processivity
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DOI：
10.1073/pnas.0711531105
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发表时间：
2008-03-25
影响因子：
11.1
通讯作者：
Trybus, Kathleen M.
中科院分区：
文献类型：
--
作者：
Ali, M. Yusuf;Lu, Hailong;Trybus, Kathleen M.
细胞器向细胞外周的运输涉及加工运动驱动蛋白和肌球蛋白 V 之间的协调运输。长程运输发生在微管轨道上，而最终的运输涉及较短的基于肌动蛋白的运动。马达仅在适当的轨道上发挥作用的概念需要进一步研究，最近观察到肌球蛋白 V 在微管上进行扩散搜索。在这里，我们使用单分子技术表明，当两个马达存在于同一货物上时，肌球蛋白 V 在微管上扩散的功能结果是驱动蛋白的加工运行长度显着增强。运行长度增强的程度与肌球蛋白 V 环 2 中的净正电荷相关。在肌动蛋白上，当驱动蛋白存在于相同货物上时，肌球蛋白 V 也会经历更长的持续运行。导致两个细胞骨架轨道上的运行长度增强的过程是静电的。我们建议一个电机充当另一个电机的系绳，并防止其扩散离开轨道，从而允许在解离之前采取更多步骤。由此产生的运行长度增强可能有助于细胞内货物的成功交付。
Organelle transport to the periphery of the cell involves coordinated transport between the processive motors kinesin and myosin V. Long-range transport takes place on microtubule tracks, whereas final delivery involves shorter actin-based movements. The concept that motors only function on their appropriate track required further investigation with the recent observation that myosin V undergoes a diffusional search on microtubules. Here we show, using single-molecule techniques, that a functional consequence of myosin V's diffusion on microtubules is a significant enhancement of the processive run length of kinesin when both motors are present on the same cargo. The degree of run length enhancement correlated with the net positive charge in loop 2 of myosin V. On actin, myosin V also undergoes longer processive runs when kinesin is present on the same cargo. The process that causes run length enhancement on both cytoskeletal tracks is electrostatic. We propose that one motor acts as a tether for the other and prevents its diffusion away from the track, thus allowing more steps to be taken before dissociation. The resulting run length enhancement likely contributes to the successful delivery of cargo in the cell.