Computational Study Of Viscoelasticity Of Crosslinked Actin-like Networks

Abstract

Mechanical force is very significantplays many important roles in eukaryotic cells in whichwhere the cross-linked actin cytoskeleton consisting largely of actin and actin binding proteins is one of the major structural components. Thus, the investigationit is critically crucial to study the of rheological properties of actin networks is indispensable in order to elucidate cell mechanics and various related cellular processes. Using Brownian dynamics, we develop a computational model equipped withthat incorporates virtues features such as including repulsive forces between actin filaments, realistic network morphology, and the consideration oftakes into account the stiffness, binding, and unbinding of actin cross-linking protein (ACP). Via bulk rheology and the analysis of thermal fluctuations of actin filaments, we elucidate investigate the viscoelastic properties of actin networks in under diverse aspectsconditions. We first validate ourThe model is first validated model by comparison with an experiments performed under similar conditions. Then, we study the influences of prestrain and ACP concentration on viscoelastic moduli, G′ and G″, are examined. The storage modulus, G′, tends is found to increase and becomes almost nearly independent of frequency at high ACP concentration or at large prestrain. We also find that the behavior of networks underAlso, under conditions of high prestrain, network rheology is governed by only a small portion of filaments that are highly stretched. Inclusion of ACP unbinding events under high prestrain results in stress relaxation and also leads to a power law behavior in G′ as observed in many cells, and causes the loss modulus, G″, to increase at low frequency. We observe Nnonlinear stress-strain behaviors of actin networks are observed that are dependent on shear strain rates and the concentration and rupture of ACP. [Supported by GM076689]