Myosins and myosin light chain kinases have been isolated from a cloned line of myoblasts (L5/A10) as this cell line undergoes differentiation toward adult muscle. At least three myosin isozymes were obtained during this developmental process. Initially a nonmuscle type of myosin was found in the myoblasts. The molecular weights of the myoblast light chains were 20 000 and 15 000. Myosin isolated from early myotubes had light chains with molecular weights of 20 000 and 19 500. Myosin isolated from myotubes which contained sarcomeres had light chains with molecular weights of 23 000, 18 500, and 16000. This last myosin was similar in light chain complement to adult rat thigh muscle. Two forms of the myosin light chain kinase activity were detected: a calciumindependent kinase in the myoblasts and a calcium-dependent kinase in the myotubes with sarcomeres. No myosin light chain kinase activity was detected in the early myotubes.
© 1981, American Chemical Society. All rights reserved.
Scordilis, Stylianos P.; Miles, J. Maurice; Adelstein, Robert S.; Uhlendorf, B. William; Scarpa, Sigfrido; and Cantoni, Giulio L., "Changes in Myosin and Myosin Light Chain Kinase During Myogenesis" (1981). Biological Sciences: Faculty Publications, Smith College, Northampton, MA.