Regulation of Actomyosin ATPase

  • Edwin W. Taylor
Conference paper
Part of the NATO ASI Series book series (NSSA, volume 135)


Muscle cells have an extremely efficient regulation system which reduces actomyosin ATPase activity by more than one thousand fold in relaxed versus active muscle. A surprising fact is that two quite different regulation systems are used in striated and smooth muscles. The actomyosin ATPase of smooth muscles as well as non muscle cells is activated by a calmodulin dependent protein kinase which specifically phosphorylates a myosin light chain (LC-2), Actomyosin is inhibited by dephosphorylation by a specific phosphatase.1 Activation of enzymes by phosphorylation is a very common control mechanism and its use in muscle regulation is not surprising. The second mechanism apparently evolved to meet the need for faster switching on and off in striated muscles. Although a phosphorylatable light chain has been retained by striated muscle myosin and the level of phosphorylation can be altered by stimulation, phosphorylation no longer activates the actomyosin ATPase. Regulation is obtained by a structural change of the thin filament. The thin filaments in striated muscle contain troponin which is not present in smooth muscle or non-muscle cells.


Myosin Light Chain Thin Filament Kinetic Mechanism Myosin Head Product Dissociation 
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  1. 1.
    Adelstein, R. S. and Eisenberg, E. (1980) Annu. Rev. Biochem. 49, 921.PubMedCrossRefGoogle Scholar
  2. 2.
    Huxley, H. E. (1972) Cold Spring Harbor Symp. Quant. Biol. 37, 361.CrossRefGoogle Scholar
  3. 3.
    Cooke, R. (1986) CRC Grit. Rev. Biochem. 21, 53.CrossRefGoogle Scholar
  4. 4.
    Botts, J., Takoshi, R., Torgerson, P., Hozumi, T., Mühlrad, A., Mornet, D. and Morales, M. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 2060.PubMedCrossRefGoogle Scholar
  5. 5.
    Chalovich, J. M. and Eisenberg, E. (1982) J. Biol. Chem. 257, 2432.PubMedGoogle Scholar
  6. 6.
    Chalovich, J. M., Greene, L. E. and Eisenberg, E. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 4909.PubMedCrossRefGoogle Scholar
  7. 7.
    Rosenfeld, S. S. and Taylor, E. W. (1987) J. Biol. Chem., in press.Google Scholar
  8. 8.
    Ikebe, M., Hinkins, S. and Hartshorne, D. J. (1983) Biochemistry 22, 4580.PubMedCrossRefGoogle Scholar
  9. 9.
    Suzuki, H., Stafford III W. F., Slayter, H. S. and Seidel, J. C. (1985) J. Biol. Chem. 260, 14810.PubMedGoogle Scholar
  10. 10.
    Rosenfeld, S. S. and Taylor, E. W. (1984) in Smooth Muscle Contraction, ed. by N. L. Stephens. M. Dekker, New York and Basel, 175.Google Scholar
  11. 11.
    Sellars, J. R. (1985) J. Biol. Chem. 260, 15815.Google Scholar
  12. 12.
    Ikebe, M. and Hartshorne, D. J. (1985) Biochemistry 24, 2380.PubMedCrossRefGoogle Scholar
  13. 13.
    Wagner, P. D. (1984) Biochemistry 23, 5950.PubMedCrossRefGoogle Scholar
  14. 14.
    Johnson, K. A. (1985) Annu. Rev. Biophys. Biophys. Chem. 14, 161.PubMedCrossRefGoogle Scholar
  15. 15.
    Hasselbach, W. (1981) in Membrane Transport, ed. by S. L. Bonting and J. H. M. dePont. Elsevier-North Holland, New York, 183.CrossRefGoogle Scholar
  16. 16.
    Mitchison, T. J. and Kirschner, M. W. (1984) Nature (London) 312, 232.CrossRefGoogle Scholar
  17. 17.
    Ross, E. M. and Gillman, A. G. (1980) Annu. Rev. Biochem. 49, 533.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • Edwin W. Taylor
    • 1
  1. 1.Department of Molecular Genetics & Cell BiologyThe University of ChicagoChicagoUSA

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