Shear thickening of F-actin networks crosslinked with non-muscle myosin IIB.
Shear thickening of F-actin networks crosslinked with non-muscle myosin IIB.
复制标题
F-肌动蛋白网络的剪切增厚与非肌肉肌球蛋白IIB交联。
DOI：
10.1039/c0sm01157f
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发表时间：
2011-01-01
期刊：
影响因子：
3.4
通讯作者：
Gardel ML
中科院分区：
文献类型：
--
作者：
Norstrom M;Gardel ML
细胞骨架F-肌动蛋白网络的材料特性促进了广泛的细胞行为，从而在某些情况下，细胞形状在力的存在下保持不变，而在其他时候，力导致不可逆的形状变化。这些行为强烈地表明，F-肌动蛋白网络可以弹性或粘性地非线性变形。虽然我们对F-actin网络的弹性刚度的调节有相当多的了解，但我们对F-actin网络的粘性行为的调节却很缺乏了解。在这里，我们研究了F-肌动蛋白网络形成的重肌球蛋白非肌肉IIB（NMMIIB）的流变行为。我们发现，NMMIIB淬火与ADP交联F-肌动蛋白成网络，足够的密度，显示应力硬化行为。通过进行一系列的蠕变测试，我们表明，密集交联的肌动蛋白/NMMIIB-ADP网络在很宽的应力范围内进行粘性变形，范围从0.001至10 Pa。在高应力下，还观察到应力剪切的网络，由此有效粘度作为应力的函数增加。剪切增稠导致在高应力下肌动蛋白/NMMIIB-ADP网络中的不可逆粘性变形的程度降低，与线性粘弹性材料的预期相比。因此，在高水平的施加力下，粘性变形对整体机械响应的贡献较小。我们的研究结果表明，在高负荷下，肌动球蛋白细胞骨架的流体样性质可以减少的机制。
The material properties of cytoskeletal F-actin networks facilitate a broad range of cellular behaviors, whereby in some situations cell shape is preserved in the presence of force and, at other times, force results in irreversible shape change. These behaviors strongly suggest that F-actin networks can variably deform elastically or viscously. While a significant amount is known about the regulation of the elastic stiffness of F-actin networks, our understanding of the regulation of viscous behaviors of F-actin networks is largely lacking. Here, we study the rheological behavior of F-actin networks formed with heavy meromyosin non-muscle IIB (NMMIIB). We show that NMMIIB quenched with ADP crosslinks F-actin into networks that, for sufficient densities, display stress stiffening behavior. By performing a series of creep tests, we show that densely crosslinked actin/NMMIIB–ADP networks undergo viscous deformation over a wide range of stresses, ranging from 0.001 to 10 Pa. At high stresses, networks that stress stiffen are also observed to shear thicken, whereby the effective viscosity increases as a function of stress. Shear thickening results in a reduction in the extent of irreversible, viscous deformation in actin/NMMIIB–ADP networks at high stresses compared to that expected for a linear viscoelastic material. Thus, viscous deformation contributes less to the overall mechanical response at high levels of applied force. Our results indicate mechanisms by which the fluid-like nature of the actomyosin cytoskeleton can be reduced under high load.