Force-Velocity Relationship in Branched Actin Networks: Consequences of Entanglement, Drag and Stall Force

Abstract

We investigate the growth of a branched actin network under load. Using a combination of simulations and theory, we show that the network adapts to the load and exhibits two regimes: a finite velocity at low stress, followed by a power-law decay of the velocity as a function of stress. This decay is explained by a theoretical model relating branched network elasticity to filament entanglement. The finite maximum velocity is attributed to network drag, which dictates dynamics at low stress. Additionally, analysis of filament stall force contribution reveals a transition from a stalled network to a growing network, when the filament stall force exceeds a critical value controlled by the applied stress.