A generalized Flory-Stockmayer kinetic theory of connectivity percolation and rigidity percolation of cytoskeletal networks.
A generalized Flory-Stockmayer kinetic theory of connectivity percolation and rigidity percolation of cytoskeletal networks.
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DOI：
10.1371/journal.pcbi.1010105
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发表时间：
2022-05
影响因子：
4.3
通讯作者：
Wolynes, Peter
中科院分区：
文献类型：
--
作者：
Bueno, Carlos;Liman, James;Schafer, Nicholas;Cheung, Margaret;Wolynes, Peter
肌动蛋白网络对于活细胞的移动、繁殖和感知环境是必不可少的。肌动蛋白网络的动态和流变行为受肌动蛋白结合蛋白的调节，如α-肌动蛋白、Arp2/3和肌球蛋白。有实验证据表明，肌动蛋白结合蛋白通过连接肌动蛋白网络来调节肌球蛋白马达的合作。在这项工作中，我们提出了一个分析平均场模型，使用Flory-Stockmayer的凝胶理论，来理解不同的肌动蛋白结合蛋白如何在网络形成时改变肌动蛋白细丝的连通性。我们跟踪网络的动力学，并估计达到连通性渗透和刚性渗透所需的肌动蛋白结合蛋白的浓度。我们发现Arp2/3以一种非单调的方式增加了网络中肌动球蛋白的连接性。我们还描述了如何改变肌动球蛋白网络的连接性来调节马达施力的能力，导致网络的三个可能的阶段具有不同的动力学特征：溶胶阶段、凝胶阶段和活动阶段。因此，细胞内肌动蛋白结合蛋白的浓度和活性的变化导致肌动蛋白网络的相变，允许细胞进行主动收缩并改变其流变性。肌动蛋白细胞骨架是一个复杂的动态系统，由与肌动蛋白细丝结合的多个蛋白质调节。一些肌动蛋白结合蛋白是交联物，可以结合成对的肌动蛋白细丝，形成肌动蛋白网络。肌动蛋白交联物可以是被动连接物，只提供结构完整性，也可以是主动连接物，如肌球蛋白马达，对网络施加作用力。实验表明，当被动交联剂的数量较少时，交联型肌动蛋白网络可以表现为粘性，而当交联剂数量较多时，交联型肌动蛋白网络会变得有弹性。只有当被动交联剂的浓度达到中等浓度时，电机才会导致网络收缩。细胞中网络的行为取决于几种不同的交联剂的浓度和活性，这些交联剂具有不同的结合位置、几何形状、亲和力和浓度。在这项工作中，我们提出了一个基于化学动力学和Flory-Stockmayer理论的简单分析模型，该模型让我们深入了解不同的交联剂如何与肌动蛋白细丝相互作用，从而导致出现的力学行为。这一理论还允许我们解析地计算网络组装过程中机械性能发展的几个关键方面。
Actin networks are essential for living cells to move, reproduce, and sense their environments. The dynamic and rheological behavior of actin networks is modulated by actin-binding proteins such as α-actinin, Arp2/3, and myosin. There is experimental evidence that actin-binding proteins modulate the cooperation of myosin motors by connecting the actin network. In this work, we present an analytical mean field model, using the Flory-Stockmayer theory of gelation, to understand how different actin-binding proteins change the connectivity of the actin filaments as the networks are formed. We follow the kinetics of the networks and estimate the concentrations of actin-binding proteins that are needed to reach connectivity percolation as well as to reach rigidity percolation. We find that Arp2/3 increases the actomyosin connectivity in the network in a non-monotonic way. We also describe how changing the connectivity of actomyosin networks modulates the ability of motors to exert forces, leading to three possible phases of the networks with distinctive dynamical characteristics: a sol phase, a gel phase, and an active phase. Thus, changes in the concentration and activity of actin-binding proteins in cells lead to a phase transition of the actin network, allowing the cells to perform active contraction and change their rheological properties. The actin cytoskeleton is a complex dynamic system, regulated by multiple proteins that bind to actin filaments. Some actin-binding proteins are crosslinkers, which can bind pairs of actin filaments, forming actin networks. Actin crosslinkers can be passive linkers, providing only structural integrity, or can be active linkers such as myosin motors, which exert forces on the network. Experiments have shown that crosslinked actin networks can behave viscously when the number of passive crosslinkers is low, but become elastic, when there are many crosslinkers. Motors can only lead to contraction of the network when there is an intermediate concentration of passive crosslinkers. The behavior of networks in the cell depends on the concentration and activity of several distinct crosslinkers, which have different binding sites, geometries, affinities, and concentrations. In this work we propose a simple analytical model based on chemical kinetics and the Flory-Stockmayer theory that gives us insight into how different crosslinkers interact with the actin filaments so as to give rise to the emergent mechanical behavior. This theory also allows us to compute analytically several crucial aspects of the development of the mechanical properties during network assembly.
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DOI：
10.1083/jcb.97.6.1745
发表时间：
1983-12
期刊：
The Journal of cell biology
影响因子：
--
作者：
Kane RE
通讯作者：
Kane RE
影响因子：
3.4
作者：
Freedman, Simon L.;Banerjee, Shiladitya;Dinner, Aaron R.
通讯作者：
Dinner, Aaron R.
DOI：
10.1073/pnas.1820814116
发表时间：
2019-08-13
影响因子：
11.1
作者：
Freedman, Simon L.;Suarez, Cristian;Hocky, Glen M.
通讯作者：
Hocky, Glen M.
影响因子：
15
作者：
Flory, PJ
通讯作者：
Flory, PJ
影响因子：
1.8
作者：
Banerjee, S.;Liverpool, T. B.;Marchetti, M. C.
通讯作者：
Marchetti, M. C.