Localization and regulation of bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase by cyclic AMP-dependent protein kinase

  • Authors:
    • Rajendra K. Sharma
    • Dallas P. Seitz
    • Baljit Singh
    • Yingchun Tan
  • View Affiliations

  • Published online on: July 1, 2002     https://doi.org/10.3892/ijmm.10.1.17
  • Pages: 17-23
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Abstract

Calmodulin-dependent cyclic nucleotide phosphodiesterase is one of the key enzymes involved in the complex interactions, which occur between the cyclic nucleotide and Ca2+ second-messenger systems. In eye, cAMP regulation is important in a variety of physiological processes such as aqueous humor regulation, photoreceptor signal transduction and retinal blood flow. Bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase was purified to apparent homogeneity and the isolated enzyme had a significantly higher affinity for calmodulin and Ca2+. Immunohistology revealed calmodulin-dependent cyclic nucleotide phospho-diesterase expression in corneal epithelium, retina and optic nerve of the eye. The cAMP-dependent protein kinase was found to catalyze the phosphorylation of bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase and the following observations were made. Firstly, the phosphorylation resulted in the incorporation of 1 mol of phosphate per mol of subunit, resulting in higher calmodulin and Ca2+ concentration requirement for calmodulin-dependent cyclic nucleotide phosphodiesterase activation. Secondly, Ca2+ and calmodulin prevented the phosphorylation. Thirdly, the phosphorylation of calmodulin-dependent cyclic nucleotide phosphodiesterase could be reversed by the calmodulin-dependent phosphatase, calcineurin. Analysis of the complex regulatory properties of the calmodulin-dependent cyclic nucleotide phosphodiesterase in the eye has led to the suggestion that fluxes of cAMP and Ca2+ during cell activation are closely coupled and that calmodulin-dependent cyclic nucleotide phosphodiesterase plays a key role in this signal coupling phenomenon.

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July 2002
Volume 10 Issue 1

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Sharma RK, Seitz DP, Singh B and Tan Y: Localization and regulation of bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase by cyclic AMP-dependent protein kinase. Int J Mol Med 10: 17-23, 2002
APA
Sharma, R.K., Seitz, D.P., Singh, B., & Tan, Y. (2002). Localization and regulation of bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase by cyclic AMP-dependent protein kinase. International Journal of Molecular Medicine, 10, 17-23. https://doi.org/10.3892/ijmm.10.1.17
MLA
Sharma, R. K., Seitz, D. P., Singh, B., Tan, Y."Localization and regulation of bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase by cyclic AMP-dependent protein kinase". International Journal of Molecular Medicine 10.1 (2002): 17-23.
Chicago
Sharma, R. K., Seitz, D. P., Singh, B., Tan, Y."Localization and regulation of bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase by cyclic AMP-dependent protein kinase". International Journal of Molecular Medicine 10, no. 1 (2002): 17-23. https://doi.org/10.3892/ijmm.10.1.17