Scale dependence of mechanics and dynamics of active gels with increasing motor concentration

Abstract

The cytoskeleton protein actin assembles into large bundles when supporting stresses in the cell, but grows into a fine branched network to induce cell motion. Such self-organization processes are studied in artificial networks of cytoskeleton proteins with thick actin bundles and large motor protein aggregates to enable optical observation. The effect of motor aggregate size on the cytoskeleton mechanical properties is studied here in networks comprised of much smaller motor assemblies. Large motor protein clusters are known to increase the stiffness of actin based networks by introducing tension and additional cross-linking cites. We find that these effects are universal to actin gels regardless of actin bundle thickness and motor aggregate size and are relevant, therefore, to a wide range of cytoskeleton based cellular processes. In contrast, motor induced active fluctuations depend significantly on motor assembly size, featuring unique non-Gaussian statistics at high concentrations of small assemblies.

12 pages 6 figures

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Cited by in corpus (9)

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• The active trap model
• Dynamics and escape of active particles in a harmonic trap
• On the generalized Langevin equation for a Rouse bead in a nonequilibrium bath
• Signatures of motor susceptibility in the dynamics of a tracer particle in an active gel
• Diffusion of an Active Particle Bound to a Generalized Elastic Model: Fractional Langevin Equation
• Non-monotonic displacement distribution of active random walkers