Mechanical coordination in motor ensembles revealed using engineered artificial myosin filaments

Nat Nanotechnol. 2015 Aug;10(8):696-700. doi: 10.1038/nnano.2015.132. Epub 2015 Jul 6.

Abstract

The sarcomere of muscle is composed of tens of thousands of myosin motors that self-assemble into thick filaments and interact with surrounding actin-based thin filaments in a dense, near-crystalline hexagonal lattice. Together, these actin-myosin interactions enable large-scale movement and force generation, two primary attributes of muscle. Research on isolated fibres has provided considerable insight into the collective properties of muscle, but how actin-myosin interactions are coordinated in an ensemble remains poorly understood. Here, we show that artificial myosin filaments, engineered using a DNA nanotube scaffold, provide precise control over motor number, type and spacing. Using both dimeric myosin V- and myosin VI-labelled nanotubes, we find that neither myosin density nor spacing has a significant effect on the gliding speed of actin filaments. This observation supports a simple model of myosin ensembles as energy reservoirs that buffer individual stochastic events to bring about smooth, continuous motion. Furthermore, gliding speed increases with cross-bridge compliance, but is limited by Brownian effects. As a first step to reconstituting muscle motility, we demonstrate human β-cardiac myosin-driven gliding of actin filaments on DNA nanotubes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry
  • Actins / metabolism
  • Bioengineering
  • DNA / chemistry
  • DNA / metabolism
  • Humans
  • Models, Biological*
  • Movement / physiology*
  • Myosins / chemistry*
  • Myosins / metabolism*
  • Myosins / ultrastructure
  • Nanotechnology
  • Nanotubes / chemistry*

Substances

  • Actins
  • DNA
  • Myosins