Active Gel Model of Amoeboid Cell Motility

TL;DR

This paper presents a biophysical model of amoeboid cell movement using active gel theory, explaining how cells spontaneously polarize and move, with predictions matching experimental observations of cell motility and optimal adhesion conditions.

Contribution

The paper introduces a novel active gel model for amoeboid motility that captures polarization, steady movement, and optimal adhesion effects, advancing understanding of cell motility mechanisms.

Findings

Active stress induces polarization and movement in the gel layer.

Steady-state movement results from a balance between contractility and filament turnover.

Maximum cell speed occurs at an optimal substrate adhesion level.

Abstract

We develop a model of amoeboid cell motility based on active gel theory. Modeling the motile apparatus of a eukaryotic cell as a confined layer of finite length of poroelastic active gel permeated by a solvent, we first show that, due to active stress and gel turnover, an initially static and homogeneous layer can undergo a contractile-type instability to a polarized moving state in which the rear is enriched in gel polymer. This agrees qualitatively with motile cells containing an actomyosin-rich uropod at their rear. We find that the gel layer settles into a steadily moving, inhomogeneous state at long times, sustained by a balance between contractility and filament turnover. In addition, our model predicts an optimal value of the gel-susbstrate adhesion leading to maximum layer speed, in agreement with cell motility assays. The model may be relevant to motility of cells translocating in complex, confining environments that can be mimicked experimentally by cell migration through microchannels.