Center for Theoretical Biological Physics, University of California, San Diego, La Jolla, California, USA.
Biophys J. 2010 Jul 7;99(1):50-8. doi: 10.1016/j.bpj.2010.03.057.
The crawling motion of Dictyostelium discoideum on substrata involves a number of coordinated events including cell contractions and cell protrusions. The mechanical forces exerted on the substratum during these contractions have recently been quantified using traction force experiments. Based on the results from these experiments, we present a biomechanical model of the contraction phase of Dictyostelium discoideum motility with an emphasis on the adhesive properties of the cell-substratum contact. Our model assumes that the cell contracts at a constant rate and is bound to the substratum by adhesive bridges that are modeled as elastic springs. These bridges are established at a spatially uniform rate while detachment occurs at a spatially varying, load-dependent rate. Using Monte Carlo simulations and assuming a rigid substratum, we find that the cell speed depends only weakly on the detachment kinetics of the cell-substratum interface, in agreement with experimental data. By varying the parameters that control the adhesive and contractile properties of the cell, we are able to make testable predictions. We also extend our model to include a flexible substrate and show that our model is able to produce substratum deformations and force patterns that are quantitatively and qualitatively in agreement with experimental data.
盘基网柄菌在基质上的爬行运动涉及许多协调事件，包括细胞收缩和细胞突起。最近，通过牵引力实验对这些收缩过程中施加在基质上的机械力进行了量化。基于这些实验的结果，我们提出了一个盘基网柄菌运动收缩阶段的生物力学模型，重点关注细胞-基质接触的粘附特性。我们的模型假设细胞以恒定的速度收缩，并通过被建模为弹性弹簧的粘附桥束缚在基质上。这些桥以空间均匀的速率建立，而脱离则以空间变化的、负载依赖的速率发生。通过使用蒙特卡罗模拟并假设刚性基质，我们发现细胞速度仅与细胞-基质界面的脱离动力学弱相关，这与实验数据一致。通过改变控制细胞粘附和收缩特性的参数，我们能够做出可测试的预测。我们还将模型扩展到包括柔性基底，并表明我们的模型能够产生与实验数据在定量和定性上一致的基底变形和力模式。
