The Regulation of cAMP-Dependent Protein Kinases in Normal and Transformed L6 Myoblasts

  • Ian A. J. Lorimer
  • B. D. Sanwal
Conference paper
Part of the NATO ASI Series book series (NSSA, volume 135)


L6 myoblasts are a permanent cell line which differentiates in culture to form multinucleate myotubes containing large numbers of the proteins characteristic of mature muscle (Yaffe, 1968). There is some evidence which suggests a role for the cAMP-dependent protein kinases in the regulation of this process (Ball and Sanwal, 1980; Curtis and Zalin, 1981). In this report we have compared the cAMP-dependent protein kinases of L6 myoblasts and a spontaneously-transformed L6 cell line which is unable to differentiate in culture. In particular we have studied the type I cAMP- dependent protein kinase as we have found previously (Rogers et al., 1984) that this isozyme is regulated during differentiation, suggesting that it is somehow involved in the control of this process. We show that the regulatory subunit of this isozyme (RI)* is degraded rapidly in L6 myoblasts in the presence of cAMP, and that this behaviour is altered in the spontaneously-transformed cell line. We also present some data which suggest a physiological role for changes in RI levels during the process of withdrawal from the cell cycle.


Regulatory Subunit Dependent Protein Kinase Myogenic Cell cAMP Analogue Myogenic Cell Line 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Ball, E. H. and Sanwal, B. D. (1980) A synergistic effect of glucocorticoids and insulin on the differentiation of myoblasts, J. Cell Physiol., 102:27.PubMedCrossRefGoogle Scholar
  2. Cates, G. A., Brickenden, A. M. and Sanwal, B. D. (1984) Possible involvement of a cell surface glycoprotein in the differentiation of skeletal myoblasts, J. Biol. Chem., 259:2646.PubMedGoogle Scholar
  3. Curtis, D. H. and Zalin, R. J. (1981) Regulation of muscle differentiation: stimulation of myoblast fusion in vitro by catecholamines. Science, 214:1355.PubMedCrossRefGoogle Scholar
  4. Dills, W. L., Beavo, J. A., Bechtel, P. J. and Krebs, E. G. (1975) Purification of rabbit skeletal muscle protein kinase regulatory subunit using cyclic adenosine 3:5-monophosphate affinity chromatography, Biochem. Biophys. Res. Comm., 62:70.PubMedCrossRefGoogle Scholar
  5. Pinset, C. and Whalen, R. G. (1984) Manipulation of medium conditions and differentiation in the rat myogenic cell line L6. Dev. Biol., 102:269PubMedCrossRefGoogle Scholar
  6. Rannels, S. R. and Corbin, J. D. (1980) Two different intrachain cAMP binding sites of cAMP-dependent protein kinases, J. Biol. Chem., 255:7085PubMedGoogle Scholar
  7. Rogers, J. E., Narindrasorasak, S., Gates, G. A. and Sanwal, B. D. (1984) Regulation of protein kinase and its regulatory subunits during skeletal myogenesis, J. Biol. Chem. 260:8002.Google Scholar
  8. Seth, P. K., Rogers, J., Narindrasorasak, S. and Sanwal, B. D. (1983) Regulation of cyclic adenosine 3:5-monophosphate phosphodiesterases: altered pattern in transformed myoblasts, J. Gell Physiol., 116:336.CrossRefGoogle Scholar
  9. Steinberg, R. A. and Agard, D. A. (1981) Turnover of regulatory subunit of cyclic AMP-dependent protein kinase in S49 mouse lymphoma cells, J. Biol. Chem., 256:10,731.Google Scholar
  10. Yaffe, D. (1968) Retention of differentiation potentialities during prolonged cultivation of myogenic cells, Proc. Natl. Acad. Sci. USA, 67:477CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • Ian A. J. Lorimer
    • 1
  • B. D. Sanwal
    • 1
  1. 1.Department of BiochemistryUniversity of Western OntarioLondonCanada

Personalised recommendations