Pattern formation and the mechanics of a motor-driven filamentous system confined by rigid membranes

TL;DR

This study models how actin filaments and myosin motors self-organize near rigid membranes, revealing a universal pattern formation mechanism driven by active and depletion forces.

Contribution

It introduces a coarse-grained molecular dynamics model showing how active forces and depletion lead to actin accumulation and structure formation near membranes.

Findings

Actin accumulates near membranes due to active and depletion forces.

The actomyosin structure exerts pressure and aligns nematically, independent of filament length.

The phenomenon is universal, unaffected by membrane curvature.

Abstract

Pattern formation and the mechanics of a mixture of actin filaments and myosin motors that is confined by a rigid membrane is investigated. By using a coarse-grained molecular dynamics model, we demonstrate that the competition between the depletion force and the active force of the motors gives rise to actin accumulation in the membrane vicinity. The resulting actomyosin structure exerts pressure on the membrane, that, due to nematic alignment of the filaments, converges to a constant for large motor active force. The results are independent of filament length and membrane curvature, indicating the universality of this phenomenon. Thus, this study proposes a novel mechanism by which the compounds of the cytoskeleton can self-organize into a higher-order structure.