Spontaneous Oscillations of a Minimal Actomyosin System under Elastic Loading

P.-Y Plaçais,T Guérin,J.-F Joanny,P Martin,M Balland

doi:10.1103/physrevlett.103.158102

Abstract

Spontaneous mechanical oscillations occur in various types of biological systems where groups of motor molecules are elastically coupled to their environment. By using an optical trap to oppose the gliding motion of a single bead-tailed actin filament over a substrate densely coated with myosin motors, we mimicked this condition in vitro. We show that this minimal actomyosin system can oscillate spontaneously. Our finding accords quantitatively with a general theoretical framework where oscillatory instabilities emerge generically from the collective dynamics of molecular motors under load.

Highlights

Spontaneous mechanical oscillations occur in various types of biological systems where groups of motor molecules are elastically coupled to their environment
Mechanical oscillations occur in a variety of biological systems
We have modified a conventional gliding assay to test the ability of a minimal actomyosin system to produce spontaneous oscillations under elastic loading

Summary

Introduction

Spontaneous mechanical oscillations occur in various types of biological systems where groups of motor molecules are elastically coupled to their environment. These motors must work against an elastic load. In the presence of 2 mM ATP, position fluctuations of the bead within the optical trap displayed three qualitative changes upon interaction of the actin filament with myosin molecules [Fig. 2(a)].

Results

Conclusion