Study of the Expression Transition of Cardiac Myosin Using Polarization-Dependent SHG Microscopy

Biophys J. 2020 Mar 10;118(5):1058-1066. doi: 10.1016/j.bpj.2019.12.030. Epub 2020 Jan 3.


Detection of the transition between the two myosin isoforms α- and β-myosin in living cardiomyocytes is essential for understanding cardiac physiology and pathology. In this study, the differences in symmetry of polarization spectra obtained from α- and β-myosin in various mammalian ventricles and propylthiouracil-treated rats are explored through polarization-dependent second harmonic generation microscopy. Here, we report for the, to our knowledge, first time that α- and β-myosin, as protein crystals, possess different symmetries: the former has C6 symmetry, and the latter has C3v. A single-sarcomere line scan further demonstrated that the differences in polarization-spectrum symmetry between α- and β-myosin came from their head regions: the head and neck domains of α- and β-myosin account for the differences in symmetry. In addition, the dynamic transition of the polarization spectrum from C6 to C3v line profile was observed in a cell culture in which norepinephrine induced an α- to β-myosin transition.

Publication types

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

MeSH terms

  • Animals
  • Cardiac Myosins*
  • Myocytes, Cardiac
  • Myosins
  • Rats
  • Sarcomeres*
  • Ventricular Myosins


  • Cardiac Myosins
  • Ventricular Myosins
  • Myosins