Enzymatic N-Methylation of Calmodulin
Calmodulin is a calcium-binding protein of 16,800 daltons which underwrites many of the enzyme-activating actions of calcium in eucaryotic tissues (Klee and Vanaman, 1982; Cheung, 1980). There are four calcium-binding domains in calmodulin; each domain binds one calcium with micromolar affinity. Calmodulin undergoes a conformational change when it binds calcium (Walsh, et al, 1979) and then can bind to calmodulinbinding proteins (Means and Dedman, 1980). altering their biological activities. Several calmodulin-binding proteins have been identified as important enzymes; these include cyclic nucleotide phosphodiesterase (Cheung, 1970), adenylate cyclase (Brostrom, et al, 1975), Ca2+, Mg2+ ATPase (Gopinath and Vincenzi, 1977), NAD kinase (Roberts, et al, 1984), protein kinase (Browning, et al, 1985), Phosphorylase kinase (Cohen, et al, 1978), myosin light chain kinase (Dabrowska, et al, 1978), tyrosine hydroxylase (Vuillet, 1985), phosphoprotein phosphatase (Klee, et al, 1983) and an hepatic protein methyltransferase (Siegel and Wright, 1985). Calmodulin also binds to a number of other calmodulin-binding proteins with as-yet-unknown biological activities. The distribution of calmodulin-binding proteins differs between tissues and subcellular fractions, presumably reflecting tissue and organelle differences in calmodulin activities (Means and Dedman, 1980).
KeywordsTyrosine Hydroxylase Myosin Light Chain Kinase Cyclic Nucleotide Phosphodiesterase Calmodulin Antagonist Phosphorylase Kinase
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- Klee, C.B., Krinks, M.H., Manalan, A.S., Cohen, P. and Stewart, A.A., 1983, Isolation and characterization of bovine brain calcineurin: a calmodulin-stimulated protein phosphatase., in Methods in Enzvmology (Means, A.R. and O’Malley, B.W., eds), 102:227.Google Scholar
- Murtaugh, T.J., Rowe, P.M., Vincent, P.L., Wright, L.S. and Siegel, F.L., 1983, Post-translational modifications of calmodulin, in Methods in Enzymology (Means, A.R. and O’Malley, B.W., eds.) Vol. 102:158, Academic Press, New York.Google Scholar
- Rowe, P.M., 1986, N-Methylation of calmodulin, Ph.D. Thesis, University of Wisconsin-Madison.Google Scholar
- Sitaramayya, A., Wright, L.S. and Siegel, F.L., 1980, Enzymatic methylation of calmodulin in rat brain cytosol. J. Biol. Chem. 256:8894.Google Scholar
- Vuillet, P.R., 1985, Direct activation of tyrosine hydroxylase by calmodulin., Proc. West. Pharmacol. Soc., 28:27.Google Scholar
- Walsh, M., Stevens, F.C., Oikawa, K. and Kay, C.M., 1979, Circular dichroism studies of native and modified Ca2+-dependent protein modulator. Canad. J. Biochem., 57:267Google Scholar