Filament turnover is essential for continuous long range contractile flow in a model actomyosin cortex

TL;DR

This study presents a minimal 2D actomyosin cortex model demonstrating that filament turnover is crucial for maintaining continuous contractile flow, linking microscopic parameters to cellular-scale cortical dynamics.

Contribution

We introduce a minimal model incorporating filament turnover and cross-link friction to analyze steady-state contractile flow in the actomyosin cortex, revealing the importance of filament turnover.

Findings

Filament turnover is essential for sustained contractile flow.

Microscopic parameters like motor activity and cross-link friction influence macroscopic flow.

The model links microscopic interactions to cellular-scale cortical deformation.

Abstract

In this paper, we develop and analyze a minimal model for a 2D network of cross-linked actin filaments and myosin motors, representing the cortical cytoskeleton of eukaryotic cells. We implement coarse-grained representations of force production by myosin motors and stress dissipation through an effective cross-link friction and filament turnover. We use this model to characterize how the sustained production of active stress, and the steady dissipation of elastic stress, depend individually on motor activity, effective cross-link friction and filament turnover. Then we combine these results to gain insights into how microscopic network parameters control steady state flow produced by asymmetric distributions of motor activity. Our results provide a framework for understanding how local modulation of microscopic interactions within contractile networks control macroscopic quantities like active stress and effective viscosity to control cortical deformation and flow at cellular scales.