title: Co-existence of nonmuscle-specific and cardiac muscle-specific myosin in myofibrils of cultured adult cardiac muscle cells.
abstract: Immunofluorescence microscopy revealed that nonmuscle myosin and cardiac muscle-specific myosin were present in the myofibrils of cultured adult cardiac muscle cells at different stages of redifferentiation including fully redifferentiated cells. Nonmuscle myosin and cardiac muscle-specific myosin were observed in amorphous or fibroamorphous form predominantly in unspread and partially spread cardiac myocytes. Nonmuscle myosin and cardiac muscle-specific myosin were present in the same striated myofibrils of the same fully redifferentiated cells. Nonmuscle myosin was localized in the Z-lines of sarcomeres of myofibrils. In double stained cells, alpha-actinin was colocalized with nonmuscle myosin in the Z-lines. The in vivo adult cardiac muscle cells contained nonmuscle myosin and cardiac muscle-specific myosin in the same myofibrils of the same cells with the localization of nonmuscle myosin in Z-lines and intercalated discs. It is evident that the nonmuscle myosin is an integral part of the sarcomeric structure of myofibrils in cardiac muscle cells.
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, Michigan 48309-4401, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Nag
authors.forename: S K
authors.initials: SK
authors.lastname: Huffaker
authors.forename: F M
authors.initials: FM
authors.lastname: Hansen-Smith
authors.forename: L
authors.initials: L
authors.lastname: Morris
mesh_terms: D000818:Animals; D024722:Cardiac Myosins / Q000378:metabolism*; D002478:Cells, Cultured; D006352:Heart Ventricles / Q000166:cytology; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure; D009210:Myofibrils / Q000737:chemistry* / Q000648:ultrastructure; D024501:Nonmuscle Myosin Type IIB / Q000378:metabolism*; D051381:Rats
chemical_list: D024722:Cardiac Myosins; D024501:Nonmuscle Myosin Type IIB