Gillo David, Gur Barak, Bernheim-Groswasser Anne, Farago Oded
Department of Chemical Engineering, Ben Gurion University, Be'er Sheva 84105, Israel.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Aug;80(2 Pt 1):021929. doi: 10.1103/PhysRevE.80.021929. Epub 2009 Aug 24.
We use a two-state ratchet model to study the cooperative bidirectional motion of molecular motors on cytoskeletal tracks with randomly alternating polarities. Our model is based on a previously proposed model [Badoual, Proc. Natl. Acad. Sci. U.S.A. 99, 6696 (2002)] for collective motor dynamics and, in addition, takes into account the cooperativity effect arising from the elastic tension that develops in the cytoskeletal track due to the joint action of the walking motors. We show, both computationally and analytically, that this additional cooperativity effect leads to a dramatic reduction in the characteristic reversal time of the bidirectional motion, especially in systems with a large number of motors. We also find that bidirectional motion takes place only on (almost) apolar tracks, while on even slightly polar tracks the cooperative motion is unidirectional. We argue that the origin of these observations is the sensitive dependence of the cooperative dynamics on the difference between the number of motors typically working in and against the instantaneous direction of motion.
我们使用双态棘轮模型来研究分子马达在极性随机交替的细胞骨架轨道上的协同双向运动。我们的模型基于先前提出的一个关于集体马达动力学的模型[巴杜阿尔，《美国国家科学院院刊》99, 6696 (2002)]，此外，还考虑了由于行走马达的联合作用在细胞骨架轨道中产生的弹性张力所引起的协同效应。我们通过计算和分析表明，这种额外的协同效应会导致双向运动的特征反转时间大幅缩短，尤其是在有大量马达的系统中。我们还发现，双向运动仅发生在（几乎）无极性的轨道上，而在即使稍有极性的轨道上，协同运动也是单向的。我们认为，这些观察结果的根源在于协同动力学对通常沿瞬时运动方向和逆着瞬时运动方向工作的马达数量之差的敏感依赖性。
