Elastic and damping forces generated by confined arrays of dynamic microtubules
Elastic and damping forces generated by confined arrays of dynamic microtubules
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DOI：
10.1088/1478-3975/3/1/006
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发表时间：
2006-03-01
期刊：
影响因子：
2
通讯作者：
Howard, J
中科院分区：
文献类型：
--
作者：
Howard, J
除了作为结构元件和作为马达蛋白的轨道，微管在生长和收缩时使用来自GTP水解的化学能来产生力。这些力被用来推动或拉动细胞器，如染色体和有丝分裂纺锤体。如果一组微管从成核位点生长出来，并被细胞的外围所限制，那么推力和拉力可以引起有趣的集体现象。在本文中，我表明，推力中心的阵列提供的微管是动态的，在这个意义上说，他们从推到收缩后，到达周边。自由端的微管动力学对于定心既不是必要的，也不是充分的。屈曲可以增加定心力。对于小的位移和速度，阵列可以非常简单地建模为阻尼弹簧。阵列的动态刚度比其静态刚度小几个数量级，并且弛豫时间与微管从中心生长到外围所需的时间相当。动态聚合物阵列与等效机械电路的替代提供了分子和细胞力学之间的桥梁。
In addition to serving as structural elements and as tracks for motor proteins, microtubules use chemical energy derived from the hydrolysis of GTP to generate forces when growing and shrinking. These forces are used to push or pull on organelles such as chromosomes and the mitotic spindle. If an array of microtubules grows out from a nucleation site and is confined by the periphery of the cell, pushing and pulling forces can give rise to interesting collective phenomena. In this paper, I show that pushing forces center the array provided that the microtubules are dynamic in the sense that they switch from pushing to shrinking after reaching the periphery. Microtubule dynamics of free ends is neither necessary nor sufficient for centering. Buckling can augment the centering force. For small displacements and velocities, the array can be modeled very simply as a damped spring. The dynamic stiffness of the array is orders of magnitude smaller than its static stiffness, and the relaxation time is on the order of the time that it takes for a microtubule to grow from the center to the periphery. Replacement of a dynamic polymer array with an equivalent mechanical circuit provides a bridge between molecular and cellular mechanics.