Resolving the Role of Actoymyosin Contractility in Cell Microrheology
Resolving the Role of Actoymyosin Contractility in Cell Microrheology
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DOI：
10.1371/journal.pone.0007054
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发表时间：
2009-09-16
期刊：
影响因子：
3.7
通讯作者：
Wirtz, Denis
中科院分区：
文献类型：
--
作者：
Hale, Christopher M.;Sun, Sean X.;Wirtz, Denis
爱因斯坦最初对布朗运动的描述建立了热激发随机力与粘性液体中亚微米粒子的传输特性之间的直接关系。最近的工作的基础上重建肌动蛋白丝网络表明，非热力学驱动的马达蛋白肌球蛋白II可以诱导大的非平衡波动，占主导地位的细胞骨架网络中的粒子的运动。在这里，使用高分辨率的粒子跟踪，我们发现，热力，而不是肌球蛋白诱导的波动力，驱动运动的亚微米颗粒嵌入在活细胞的细胞骨架。这些结果解决了肌球蛋白II和收缩性肌动球蛋白结构在驻留在细胞质中的纳米颗粒运动中的作用，揭示了粘附细胞的双相机械结构-在细胞皮质处的网络中交错的刚性收缩应力纤维和细胞体内的软肌动蛋白网络，验证了颗粒跟踪-微流变学的方法，并调和看似不同的原子力显微镜（AFM）和粒子跟踪活细胞的微观流变学测量。
Einstein's original description of Brownian motion established a direct relationship between thermally-excited random forces and the transport properties of a submicron particle in a viscous liquid. Recent work based on reconstituted actin filament networks suggests that nonthermal forces driven by the motor protein myosin II can induce large non-equilibrium fluctuations that dominate the motion of particles in cytoskeletal networks. Here, using high-resolution particle tracking, we find that thermal forces, not myosin-induced fluctuating forces, drive the motion of submicron particles embedded in the cytoskeleton of living cells. These results resolve the roles of myosin II and contractile actomyosin structures in the motion of nanoparticles lodged in the cytoplasm, reveal the biphasic mechanical architecture of adherent cells-stiff contractile stress fibers interdigitating in a network at the cell cortex and a soft actin meshwork in the body of the cell, validate the method of particle tracking-microrheology, and reconcile seemingly disparate atomic force microscopy (AFM) and particle-tracking microrheology measurements of living cells.