Excitable actin dynamics and amoeboid cell migration

TL;DR

This paper demonstrates that excitable actin dynamics can spontaneously generate waves that drive amoeboid cell migration, revealing a deterministic mechanism underlying the random walk behavior of migrating cells.

Contribution

It introduces a phase-field model showing how actin filament waves lead to persistent random walks, linking actin dynamics parameters to migration behavior.

Findings

Actin wave dynamics can produce spontaneous cellular movement.

Migration characteristics depend on actin assembly speed and nucleator inactivation rate.

Cells may modulate migration by altering actin pool availability.

Abstract

Amoeboid cell migration is characterized by frequent changes of the direction of motion and resembles a persistent random walk on long time scales. Although it is well known that cell migration is typically driven by the actin cytoskeleton, the cause of this migratory behavior remains poorly understood. We analyze the spontaneous dynamics of actin assembly due to nucleation promoting factors, where actin filaments lead to an inactivation of the nucleators. We show that this system exhibits excitable dynamics and can spontaneously generate waves, which we analyse in detail. By using a phase-field approach, we show that these waves can generate cellular random walks. We explore how the characteristics of these persistent random walks depend on the parameters governing the actin-nucleator dynamics. In particular, we find that the effective diffusion constant and the persistence time depend strongly on the speed of filament assembly and the rate of nucleator inactivation. Our findings point to a deterministic origin of the random walk behavior and suggest that cells could adapt their migration pattern by modifying the pool of available actin.