Gardel M L, Shin J H, MacKintosh F C, Mahadevan L, Matsudaira P, Weitz D A
Department of Physics, Harvard University, Cambridge, MA 02138, USA.
Science. 2004 May 28;304(5675):1301-5. doi: 10.1126/science.1095087.
Networks of cross-linked and bundled actin filaments are ubiquitous in the cellular cytoskeleton, but their elasticity remains poorly understood. We show that these networks exhibit exceptional elastic behavior that reflects the mechanical properties of individual filaments. There are two distinct regimes of elasticity, one reflecting bending of single filaments and a second reflecting stretching of entropic fluctuations of filament length. The mechanical stiffness can vary by several decades with small changes in cross-link concentration, and can increase markedly upon application of external stress. We parameterize the full range of behavior in a state diagram and elucidate its origin with a robust model.
交联和束状肌动蛋白丝网络在细胞骨架中普遍存在，但其弹性仍知之甚少。我们表明，这些网络表现出异常的弹性行为，反映了单个丝的力学性质。存在两种不同的弹性状态，一种反映单丝的弯曲，另一种反映丝长度的熵涨落的拉伸。机械刚度可随交联浓度的微小变化而变化数十年，并在施加外部应力时显著增加。我们在状态图中对整个行为范围进行参数化，并用一个稳健的模型阐明其起源。
