Optogenetic switching of migration of contractile cells

TL;DR

This paper presents a theoretical model demonstrating how optogenetics can control cell migration by switching between stationary and motile states through regulation of contractility.

Contribution

It introduces a thermodynamically rigorous active gel model that predicts bistability and controllable switching of cell migration states via optogenetic activation.

Findings

Model predicts bistability between sessile and motile cells.

Switching between states is achievable with realistic optogenetic parameters.

Predicted activation strengths and times match recent experimental data.

Abstract

Cell crawling on flat substrates is based on intracellular flows of the actin cytoskeleton that are driven by both actin polymerization at the front and myosin contractility at the back. The new experimental tool of optogenetics makes it possible to spatially control contraction and thereby possibly also cell migration. Here we analyze this situation theoretically using a one-dimensional active gel model in which the excluded volume interactions of myosin and their aggregation into minifilaments is modeled by a supercritical van der Waals fluid. This physically simple and transparent, but nonlinear and thermodynamically rigorous model predicts bistability between sessile and motile solutions. We then show that one can switch between these two states at realistic parameter ranges via optogenetic activation or inhibition of contractility, in agreement with recent experiments. We also predict the required activation strengths and initiation times.