Dendritic Actin Filament Nucleation Causes Traveling Waves and Patches

TL;DR

This paper simulates actin polymerization to reveal how nucleation causes traveling waves and patches, showing a concentration-dependent transition and mechanisms independent of myosin II.

Contribution

It introduces a stochastic-growth simulation of actin nucleation that uncovers the formation of traveling waves and patches without myosin II involvement.

Findings

Actin polymerization exhibits waves, patches, and fluctuations.

Increasing actin concentration transitions patches into waves.

Waves and patches move via treadmilling, independent of myosin II.

Abstract

The polymerization of actin via branching at a cell membrane containing nucleation-promoting factors is simulated using a stochastic-growth methodology. The polymerized-actin distribution displays three types of behavior: a) traveling waves, b) moving patches, and c) random fluctuations. Increasing actin concentration causes a transition from patches to waves. The waves and patches move by a treadmilling mechanism which does not require myosin II. The effects of downregulation of key proteins on actin wave behavior are evaluated.