In vivo myosin step-size from zebrafish skeletal muscle

Thomas P. Burghardt, Katalin Ajtai, Xiaojing Sun, Naoko Takubo, Yihua Wang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Muscle myosins transduce ATP free energy into actin displacement to power contraction. In vivo, myosin side chains are modified post-translationally under native conditions, potentially impacting function. Single myosin detection provides the 'bottom-up' myosin characterization probing basic mechanisms without ambiguities inherent to ensemble observation. Macroscopic muscle physiological experimentation provides the definitive 'top-down' phenotype characterizations that are the concerns in translational medicine. In vivo single myosin detection in muscle from zebrafish embryo models for human muscle fulfils ambitions for both bottom-up and topdown experimentation. A photoactivatable green fluorescent protein (GFP)-tagged myosin light chain expressed in transgenic zebrafish skeletal muscle specifically modifies the myosin lever-arm. Strychnine induces the simultaneous contraction of the bilateral tail muscles in a live embryo, causing them to be isometric while active. Highly inclined thin illumination excites the GFP tag of single lever-arms and its super-resolution orientation is measured from an active isometric muscle over a time sequence covering many transduction cycles. Consecutive frame lever-arm angular displacement converts to step-size by its product with the estimated lever-arm length. About 17% of the active myosin steps that fall between 2 and 7 nm are implicated as powerstrokes because they are beyond displacements detected from either relaxed or ATP-depleted (rigor) muscle.

Original languageEnglish (US)
Article number160075
JournalOpen biology
Issue number5
StatePublished - May 2016


  • Highly inclined thin illumination
  • Single myosin detection in vivo
  • Strychnine induced contraction
  • Transgenic zebrafish skeletal muscle
  • Zebrafish skeletal myosin powerstroke
  • Zebrafish skeletal myosin step-size

ASJC Scopus subject areas

  • General Neuroscience
  • Immunology
  • General Biochemistry, Genetics and Molecular Biology


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