Bioquant, University of Heidelberg, Heidelberg, Germany.
J Phys Condens Matter. 2010 May 19;22(19):194112. doi: 10.1088/0953-8984/22/19/194112. Epub 2010 Apr 26.
In migrating cells, retrograde flow of the actin cytoskeleton is related to traction at adhesion sites located at the base of the lamellipodium. The coupling between the moving cytoskeleton and the stationary adhesions is mediated by the continuous association and dissociation of molecular bonds. We introduce a simple model for the competition between the stochastic dynamics of elastic bonds at the moving interface and relaxation within the moving actin cytoskeleton represented by an internal viscous friction coefficient. Using exact stochastic simulations and an analytical mean field theory, we show that the stochastic bond dynamics lead to biphasic friction laws as observed experimentally. At low internal dissipation, stochastic bond dynamics lead to a regime of irregular stick-and-slip motion. High internal dissipation effectively suppresses cooperative effects among bonds and hence stabilizes the adhesion.
在迁移细胞中，肌动蛋白细胞骨架的逆行流动与位于片状伪足底部的黏附位点处的牵引力有关。运动细胞骨架和固定黏附之间的耦合是通过分子键的连续结合和解离来介导的。我们引入了一个简单的模型，用于在运动界面处的弹性键的随机动力学和由内部粘性摩擦系数表示的运动肌动蛋白细胞骨架内的弛豫之间的竞争。使用精确的随机模拟和分析的平均场理论，我们表明随机键动力学导致实验观察到的双相摩擦定律。在低内部耗散的情况下，随机键动力学导致不规则的粘滑运动状态。高内部耗散有效地抑制了键之间的协同作用，从而稳定了黏附。
