A mechanism for cell motility by active polar gels

TL;DR

This paper presents a hydrodynamic model of cell motility driven by contractile stresses from myosin-actin interactions, capturing cell movement without adhesion and analyzing flow fields akin to squirmer models.

Contribution

It introduces a comprehensive active polar gel model combined with membrane mechanics to simulate cell motility without adhesion, including numerical analysis and flow field comparison.

Findings

Cell motility can be modeled without adhesion mechanisms.

Flow fields resemble those of classical squirmer models.

Cell behavior as a puller or pusher depends on myosin-actin interaction strength.

Abstract

We analyse a generic motility model, with the motility mechanism arising by contractile stress due to the interaction of myosin and actin. A hydrodynamic active polar gel theory is used to model the cytoplasm of a cell and is combined with a Helfrich-type model to account for membrane properties. The overall model allows to consider motility without the necessity for local adhesion. Besides a detailed numerical approach together with convergence studies for the highly nonlinear free boundary problem, we also compare the induced flow field of the motile cell with that of classical squirmer models and identify the motile cell as a puller or pusher, depending on the strength of the myosin-actin interactions.