Active contractility in actomyosin networks

Abstract

Contractile forces are essential for many developmental processes involving cell shape change and tissue deformation. Recent experiments on reconstituted actomyosin networks, the major component of the contractile machinery, have shown that active contractility occurs above a threshold motor concentration and within a window of crosslink concentration. We present a microscopic dynamic model that incorporates two essential aspects of actomyosin self-organization: the asymmetric load response of individual actin filaments and the correlated motor-driven events mimicking myosin-induced filament sliding. Using computer simulations we examine how the concentration and susceptibility of motors contribute to their collective behavior and interplay with the network connectivity to regulate macroscopic contractility. Our model is shown to capture the formation and dynamics of contractile structures and agree with the observed dependence of active contractility on microscopic parameters including the contractility onset. Cooperative action of load-resisting motors in a force-percolating structure integrates local contraction/buckling events into a global contractile state via an active coarsening process, in contrast to the flow transition driven by uncorrelated kicks of susceptible motors.

15 pages, 4 main figures, 4 supplementary figures

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Cited by in corpus (23)

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• Temperature response of the neuronal cytoskeleton mapped via atomic force and fluorescence microscopy
• Colloidal transport by active filaments
• Stochastic Ratcheting on a Funneled Energy Landscape is Necessary for Highly Efficient Contractility of Actomyosin Force Dipoles
• Signatures of motor susceptibility in the dynamics of a tracer particle in an active gel
• Understanding cytoskeletal avalanches using mechanical stability analysis
• Microscopic theory of the glassy dynamics of passive and active network materials
• Dynamics in Steady State In Vitro Acto-Myosin Networks
• Traveling waves at the surface of active liquid crystals
• Strain-controlled critical slowing down in the rheology of disordered networks
• Modeling Multi-Cellular Dynamics Regulated by ECM-Mediated Mechanical Communication via Active Particles with Polarized Effective Attraction
• Active biopolymer networks generate scale-free but euclidean clusters
• Active patterning and asymmetric transport in a model actomyosin network
• Motorized Chromosome Models of Mitosis
• Lattice Boltzmann simulations of self-propelling chiral active droplets
• Motility and self propulsion of active droplets
• Statistics of Thermal Avalanches in Driven Amorphous Systems
• Force generation by Myosin II Filaments in Compliant Networks