An estimate to the first approximation of microtubule rupture force
An estimate to the first approximation of microtubule rupture force
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DOI：
10.1007/s00249-019-01371-6
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发表时间：
2019-09-01
影响因子：
2
通讯作者：
Marszalek, Piotr E.
中科院分区：
文献类型：
--
作者：
Endow, Sharyn A.;Marszalek, Piotr E.
微管的力学性质对于理解基本的细胞过程是必不可少的，包括细胞的运动和分裂，但导致微管断裂或断裂的力尚未被直接测量。这些力对于了解细胞骨架的机械特性以及细胞对正常条件和由损伤或疾病引起的压力的反应至关重要。在这里，我们通过在整体动力分析中分析Kinesin-14 NCD马达诱导的微管断裂来估计断裂微管所需的力。我们将破裂事件模拟为NCD电机对单个微管的拉动或推动，这些微管的一端被连接到玻璃表面的其他电机夹住。拉力或推力NCD马达的数量是根据与表面结合的微管的长度来近似的，而拉力或推力马达所产生的力是根据NCD马达在激光陷阱分析中所产生的力来估计的，如其他人所报道的那样。我们的分析提供了一个初步估计，对于破裂13-pF微管所需的最小力，类似于500pN。我们报告的值与微管拉伸/碎裂实验中估计的力接近，并与AFM在微管压痕试验中施加的力重叠，微管压痕试验破坏微管的稳定并破坏微管原丝。这也与力光谱实验中破坏蛋白质非共价键所需的力是一致的。这些发现与体内细胞张力引起的微管变形和断裂有关。
Microtubule mechanical properties are essential for understanding basic cellular processes, including cell motility and division, but the forces that result in microtubule rupture or breakage have not yet been measured directly. These forces are essential to understand the mechanical properties of the cytoskeleton and responses by cells to both normal conditions and stress caused by injury or disease. Here we estimate the force required to rupture a microtubule by analyzing kinesin-14 Ncd motor-induced microtubule breakage in ensemble motility assays. We model the breakage events as caused by Ncd motors pulling or pushing on single microtubules that are clamped at one end by other motors attached to the glass surface. The number of pulling or pushing Ncd motors is approximated from the length of the microtubule bound to the surface and the forces produced by the pulling or pushing motors are estimated from forces produced by the Ncd motor in laser-trap assays, reported by others. Our analysis provides an estimate, to the first approximation, of similar to 500 pN for the minimal force required to rupture a 13-pf microtubule. The value we report is close to the forces estimated from microtubule stretching/fragmentation experiments and overlaps with the forces applied by AFM in microtubule indentation assays that destabilize microtubules and break microtubule protofilaments. It is also consistent with the forces required to disrupt protein noncovalent bonds in force spectroscopy experiments. These findings are relevant to microtubule deformation and breakage caused by cellular tension in vivo.