Aström Jan A, Kumar P B Sunil, Vattulainen Ilpo, Karttunen Mikko
CSC-Finnish IT Center for Science, Esbo, Finland.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 May;77(5 Pt 1):051913. doi: 10.1103/PhysRevE.77.051913. Epub 2008 May 16.
Actin filament networks enable the cytoskeleton to adjust to internal and external forcing. These dynamic networks can adapt to changes by dynamically adjusting their cross-links. Here, we model actin filaments as cross-linked elastic fibers of finite dimensions, with the cross-links being approximately 1 mum apart, and employ a full three-dimensional model to study their elastic properties by computer simulations. The results show compelling evidence that dense actin networks are characterized by (a) strain hardening without entropic elasticity, (b) avalanches of cross-link slippage leading to strain softening in the case of breakable cross-links, and (c) spontaneous formation of stress fibers in the case of dynamic cross-link formation and destruction.
肌动蛋白丝网络使细胞骨架能够适应内部和外部作用力。这些动态网络可以通过动态调整其交联来适应变化。在这里，我们将肌动蛋白丝建模为有限尺寸的交联弹性纤维，交联间距约为1微米，并采用全三维模型通过计算机模拟研究其弹性特性。结果显示了令人信服的证据，即致密的肌动蛋白网络具有以下特征：(a) 应变硬化而无熵弹性；(b) 在可断裂交联的情况下，交联滑移雪崩导致应变软化；(c) 在动态交联形成和破坏的情况下，应力纤维的自发形成。
