ABSTRACT
A physical analysis of the dynamics and mechanics of contractile actin rings is presented. In particular, the dynamics of ring contraction during cytokinesis in the Caenorhabditis elegans embryo is analyzed. A general analysis of force balances and material exchange is presented and estimate the relevant parameter values. It is shown that on a microscopic level contractile stresses can result from both the action of motor proteins, which cross-link filaments, and from the polymerization and depolymerization of filaments in the presence of end-tracking cross-linkers.
