Interplay between Brownian motion and cross-linking controls bundling dynamics in actin networks
Interplay between Brownian motion and cross-linking controls bundling dynamics in actin networks
复制标题
布朗运动和交联之间的相互作用控制肌动蛋白网络中的捆绑动力学
DOI：
10.1016/j.bpj.2022.02.030
复制
发表时间：
2022
影响因子：
3.4
通讯作者：
Mogilner, Alex
中科院分区：
文献类型：
--
作者：
Maxian, Ondrej;Donev, Aleksandar;Mogilner, Alex
交联肌动蛋白网络的形态变化对于细胞运动、分裂和货物运输很重要。在这里，我们通过微观布朗动力学模拟研究从肌动蛋白丝的弱交联网络到肌动蛋白束的重交联网络的转变。我们表明这种转变发生在两个阶段：首先，小且高度对齐的束的复合束网络由单个细丝的交联演变而来，其次，小束合并成簇束状态。我们证明布朗运动以比第二阶段更快的速度加速该过程的第一阶段。我们量化了达到复合束状态的时间，并表明，仅当交联浓度较小时，它会随着网格尺寸的增加而强烈增加，并且如果我们随着肌动蛋白浓度的增加而降低交联剂的相对比例，则它会保持大致恒定。最后，我们检查了成束时间尺度对细丝长度的依赖性，发现较短的细丝捆绑得更快，因为它们扩散得更快。
Morphology changes in cross-linked actin networks are important in cell motility, division, and cargo transport. Here, we study the transition from a weakly cross-linked network of actin filaments to a heavily cross-linked network of actin bundles through microscopic Brownian dynamics simulations. We show that this transition occurs in two stages: first, a composite bundle network of small and highly aligned bundles evolves from cross-linking of individual filaments and, second, small bundles coalesce into the clustered bundle state. We demonstrate that Brownian motion speeds up the first stage of this process at a faster rate than the second. We quantify the time to reach the composite bundle state and show that it strongly increases as the mesh size increases only when the concentration of cross-links is small and that it remains roughly constant if we decrease the relative ratio of cross-linkers as we increase the actin concentration. Finally, we examine the dependence of the bundling timescale on filament length, finding that shorter filaments bundle faster because they diffuse faster.