Self-organization and Mechanical Properties of Active Filament Bundles

TL;DR

This paper presents a phenomenological model of active filament bundles, capturing dynamic behaviors like contraction, oscillations, and self-organized transport, inspired by cytoskeletal phenomena in cells.

Contribution

It introduces a minimal, momentum-conserving model that explains various dynamic states and self-organization in active filament bundles, relevant to cellular mechanics.

Findings

Bundles can actively contract and perform work against external forces.

Dynamic instabilities lead to oscillatory and solitary wave behaviors.

Filament adhesion induces persistent self-organized transport.

Abstract

A phenomenological description for active bundles of polar filaments is presented. The activity of the bundle results from crosslinks, that induce relative displacements between the aligned filaments. Our generic description is based on momentum conservation within the bundle. By specifying the internal forces, a simple minimal model for the bundle dynamics is obtained, capturing generic dynamic behaviors. In particular, contracted states as well as solitary and oscillatory waves appear through dynamic instabilities. The introduction of filament adhesion leads to self-organized persistent filament transport. Furthermore, calculating the tension, homogeneous bundles are shown to be able to actively contract and to perform work against external forces. Our description is motivated by dynamic phenomena in the cytoskeleton and could apply to stress-fibers and self-organization phenomena during cell-locomotion.