Membrane tension feedback on shape and motility of eukaryotic cells

TL;DR

This paper uses a phase field model to study how membrane tension influences the shape and movement of eukaryotic cells, highlighting the dominant role of tension feedback on actin polymerization.

Contribution

It introduces a comprehensive model incorporating membrane tension effects, actin dynamics, and membrane properties to explain cell motility and shape changes.

Findings

Membrane tension feedback significantly affects cell velocity and shape.

Bending rigidity has minor effects, mainly during dynamic reshaping.

Cell motility is primarily governed by tension-mediated regulation of actin polymerization.

Abstract

In the framework of a phase field model of a single cell crawling on a substrate, we investigate how the properties of the cell membrane affect the shape and motility of the cell. Since the membrane influences the cell dynamics on multiple levels and provides a nontrivial feedback, we consider the following fundamental interactions: (i) the reduction of the actin polymerization rate by membrane tension; (ii) area conservation of the cell's two-dimensional cross-section vs. conservation of its circumference (i.e. membrane inextensibility); and (iii) the contribution from the membrane's bending energy to the shape and integrity of the cell. As in experiments, we investigate two pertinent observables -- the cell's velocity and its aspect ratio. We find that the most important effect is the feedback of membrane tension on the actin polymerization. Bending rigidity has only minor effects, visible mostly in dynamic reshaping events, as exemplified by collisions of the cell with an obstacle.