title: Regulation of myosin and overall protein degradation in mouse C2 skeletal myotubes.
abstract: We compared the breakdown of total cellular protein with that of the contractile protein, myosin, in cultured C2 mouse skeletal myotubes. The degradation of long-lived cellular proteins (which comprise the vast majority of myotube proteins) was inhibited by serum, insulin, and rat insulin-like growth factor-2. A physiological concentration of insulin was effective, but most of the effect of insulin occurred at concentrations well above the physiological range. IGF-2 inhibited protein breakdown at concentrations well within the range of total IGF-2 known to be present in the serum of fetal and neonatal rats. The breakdown of short-lived proteins was not altered by insulin or serum. We measured myosin degradation using a monoclonal antibody directed against myosin heavy chain. The half-life of myosin was 27 hours, and myosin breakdown was not altered by serum withdrawal applies to certain proteins, but not to others.
authors.affiliation: Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, MA 02115.
authors.forename: E A
authors.initials: EA
authors.lastname: Gulve
authors.forename: K
authors.initials: K
authors.lastname: Mabuchi
authors.forename: J F
authors.initials: JF
authors.lastname: Dice
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002454:Cell Differentiation; D002478:Cells, Cultured; D003470:Culture Media; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology; D051379:Mice; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D011994:Recombinant Proteins
chemical_list: D000911:Antibodies, Monoclonal; D003470:Culture Media; D007328:Insulin; D009124:Muscle Proteins; D011994:Recombinant Proteins; D007335:Insulin-Like Growth Factor II; D009218:Myosins