Structure formation in active networks

TL;DR

This study reveals how a minimal active network system of actin filaments, crosslinkers, and motors self-organizes into dynamic structures through a balance of stabilization and destabilization, mimicking cellular behavior.

Contribution

It introduces a minimal reconstituted active network model demonstrating generic structure formation mechanisms driven by force balance, coarsening, and connectivity.

Findings

Structures exhibit a broad size distribution.

Growth depends on crosslinker and motor interactions.

The system shows anomalous transport dynamics.

Abstract

Structure formation and constant reorganization of the actin cytoskeleton are key requirements for the function of living cells. Here we show that a minimal reconstituted system consisting of actin filaments, crosslinking molecules and molecular-motor filaments exhibits a generic mechanism of structure formation, characterized by a broad distribution of cluster sizes. We demonstrate that the growth of the structures depends on the intricate balance between crosslinker-induced stabilization and simultaneous destabilization by molecular motors, a mechanism analogous to nucleation and growth in passive systems. We also show that the intricate interplay between force generation, coarsening and connectivity is responsible for the highly dynamic process of structure formation in this heterogeneous active gel, and that these competing mechanisms result in anomalous transport, reminiscent of intracellular dynamics.