Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel.
J Phys Condens Matter. 2010 May 19;22(19):194111. doi: 10.1088/0953-8984/22/19/194111. Epub 2010 Apr 26.
The response of cells to shear flow is primarily determined by the asymmetry of the external forces and moments that are sensed by each member of a focal adhesion pair connected by a contractile stress fiber. In the theory presented here, we suggest a physical model in which each member of such a pair of focal adhesions is treated as an elastic body subject to both a myosin-activated contractile force and the shear stress induced by the external flow. The elastic response of a focal adhesion complex is much faster than the active cellular processes that determine the size of the associated focal adhesions and the direction of the complex relative to the imposed flow. Therefore, the complex attains its mechanical equilibrium configuration which may change because of the cellular activity. Our theory is based on the experimental observation that focal adhesions modulate their cross-sectional area in order to attain an optimal shear. Using this assumption, our elastic model shows that such a complex can passively change its orientation to align parallel to the direction of the flow.
细胞对剪切流的反应主要取决于由连接在收缩应力纤维上的粘着斑对中每个成员感知到的外力和力矩的不对称性。在本文提出的理论中，我们提出了一个物理模型，其中这样的粘着斑对中的每个成员都被视为一个弹性体，受到肌球蛋白激活的收缩力和外部流动引起的剪切应力的作用。粘着斑复合物的弹性响应比决定相关粘着斑大小和复合物相对于施加流的方向的主动细胞过程快得多。因此，复合物达到其机械平衡构型，由于细胞活性，该构型可能会发生变化。我们的理论基于实验观察，即粘着斑调节其横截面积以达到最佳剪切。使用此假设，我们的弹性模型表明，这样的复合物可以被动地改变其方向以与流动方向平行对齐。
