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Distribution and dynamics of nonmuscle myosins IIs in cardiac and in skeletal muscle cells
Author(s) -
Sanger Joseph W.,
Wang Jushuo,
White Jennifer,
Sanger Jean M.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.180.7
Subject(s) - myofibril , myosin , skeletal muscle , myocyte , actin , sarcomere , gene isoform , microbiology and biotechnology , transfection , cardiac muscle , biology , chemistry , anatomy , biochemistry , gene
We have proposed a three‐step model for myofibrillogenesis: premyofibrils to nascent myofibrils to mature myofibrils that involves nonmuscle myosin II presence only in the first two steps. However, it has been reported (Takeda et al., 2000) that antibodies directed against nonmuscle myosin IIs stained the Z‐bands of mature myofibrils and intercalated discs of striated muscle cells. We have used similar nonmuscle myosin II antibodies against intact hearts and cultured cardiac and skeletal muscle cells and did not obtained these results. We have transfected cultures of embryonic avian cardiac and skeletal muscle cells with GFP plasmids encoding the three different isoforms of nonmuscle myosin II (A, B or C). The cells were cotransfected with CeruleanFP plasmids encoding sarcomeric alpha‐actinin, a marker for z‐bodies and Z‐bands. The three different GFP‐nonmuscle myosin II proteins localized to the premyofibrils and nascent myofibrils alternating with z‐bodies (as identified by CeFP‐alpha‐actinin localizations). The nonmuscle myosins never localized to the Z‐bands (identified by CeFP‐alpha‐actinin) or any other region of the mature myofibrils in the muscle cells. Our results support the idea that nonmuscle myosin IIs participate in aligning the z‐bodies and their attached actin filaments in premyofibrils and nascent myofibrils, preceding the formation of the mature myofibril. Research support: NIH.