Molecular Model of the Contractile Ring

TL;DR

This paper introduces a physical model of the actin-based contractile ring in animal cell cytokinesis, emphasizing actin dynamics and viscous dissipation, aligning well with experimental observations.

Contribution

It provides a novel physical model explaining actin concentration changes and biphasic cytokinesis in animal cells.

Findings

Actin concentration increases during ring contraction.

Viscous dissipation dominates the ring's dynamics.

The model aligns with experimental measurements.

Abstract

We present a model for the actin contractile ring of adherent animal cells. The model suggests that the actin concentration within the ring and consequently the power that the ring exerts both increase during contraction. We demonstrate the crucial role of actin polymerization and depolymerization throughout cytokinesis, and the dominance of viscous dissipation in the dynamics. The physical origin of two phases in cytokinesis dynamics ("biphasic cytokinesis") follows from a limitation on the actin density. The model is consistent with a wide range of measurements of the midzone of dividing animal cells.