Percolation with trapping mechanism drives active gels to the critically connected state

TL;DR

This paper proposes that actomyosin networks naturally reach a critical state similar to percolation with trapping, explaining their power-law cluster size distribution without fine-tuning, and offers testable predictions based on this model.

Contribution

The authors introduce a modified percolation with trapping model to explain the critical behavior of actomyosin networks without fine-tuning.

Findings

Actomyosin networks exhibit power-law cluster size distribution.

The dynamics can be mapped onto a percolation with trapping model.

Model provides experimentally testable predictions.

Abstract

Cell motility and tissue morphogenesis depend crucially on the dynamic remodelling of actomyosin networks. An actomyosin network consists of an actin polymer network connected by crosslinker proteins and motor protein myosins that generate internal stresses on the network. A recent discovery shows that for a range of experimental parameters, actomyosin networks contract to clusters with a power-law size distribution [Alvarado J. et al. (2013) Nature Physics 9 591]. Here, we argue that actomyosin networks can exhibit robust critical signature without fine-tuning because the dynamics of the system can be mapped onto a modified version of percolation with trapping (PT), which is known to show critical behaviour belonging to the static percolation universality class without the need of fine-tuning of a control parameter. We further employ our PT model to generate experimentally testable predictions.