Branching, Capping, and Severing in Dynamic Actin Structures

TL;DR

This paper presents a mathematical model of actin network dynamics, analyzing how processes like branching, capping, and severing influence cell motility and network structure, with findings aligning with observed in vivo cell behavior.

Contribution

It introduces a new formulation of actin network processes and analyzes their steady-state morphology, revealing optimal coupling conditions for severing and branching in vivo.

Findings

Identifies scaling regimes in severing and branching protein concentrations.

Coupling between severing and branching is optimized for in vivo conditions.

Model predictions qualitatively match in vivo actin network morphology.

Abstract

Branched actin networks at the leading edge of a crawling cell evolve via protein-regulated processes such as polymerization, depolymerization, capping, branching, and severing. A formulation of these processes is presented and analyzed to study steady-state network morphology. In bulk, we identify several scaling regimes in severing and branching protein concentrations and find that the coupling between severing and branching is optimally exploited for conditions {\it in vivo}. Near the leading edge, we find qualitative agreement with the {\it in vivo} morphology.