Coupling biochemistry and mechanics in cell adhesion: a model for inhomogeneous stress fiber contraction

TL;DR

This paper presents a coupled biochemical-mechanical model of stress fiber contraction in cell adhesion, revealing spatial gradients in contractility and deformation consistent with experimental observations.

Contribution

It introduces a novel reaction-diffusion and viscoelastic model linking Rho-pathway signaling to stress fiber mechanics in cell adhesion.

Findings

Strong spatial gradients in contractility activation

Deformation patterns match experimental data

Model captures feedback loop in adhesion mechanics

Abstract

Biochemistry and mechanics are closely coupled in cell adhesion. At sites of cell-matrix adhesion, mechanical force triggers signaling through the Rho-pathway, which leads to structural reinforcement and increased contractility in the actin cytoskeleton. The resulting force acts back to the sites of adhesion, resulting in a positive feedback loop for mature adhesion. Here we model this biochemical-mechanical feedback loop for the special case when the actin cytoskeleton is organized in stress fibers, which are contractile bundles of actin filaments. Activation of myosin II molecular motors through the Rho-pathway is described by a system of reaction-diffusion equations, which are coupled into a viscoelastic model for a contractile actin bundle. We find strong spatial gradients in the activation of contractility and in the corresponding deformation pattern of the stress fiber, in good agreement with experimental findings.