Calcium and muscarinic agonist stimulation of type I adenylylcyclase in whole cells

E. J. Choi, S. T. Wong, T. R. Hinds, D. R. Storm

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8 Citations (Scopus)


The type I adenylylcyclase which was originally purified and cloned from bovine brain is stimulated by Ca2+ and calmodulin in vitro. Although it has been proposed that this enzyme may couple elevations in intracellular Ca2+ to increases in cAMP in whole cells, this has not been demonstrated in vivo. In this study, the type I adenylylcyclase was expressed in human 293 cells, and the influence of extracellular Ca2+ and Ca2+ ionophore on intracellular cAMP levels was examined. The cAMP levels of control cells were unaffected by Ca2+ and A23187. In contrast, intracellular cAMP in 293 cells expressing type I adenylylcyclase was markedly elevated by addition of A23187 and extracellular Ca2+. In the presence of forskolin, the muscarinic agonist carbachol also increased cAMP in 293 cells expressing the type I adenylylcyclase. These data indicate that the type I adenylylcyclase can be stimulated by Ca2+ in vivo, and that muscarinic agonists may indirectly stimulate the enzyme by increasing intracellular free Ca2+.

Original languageEnglish
Pages (from-to)12440-12442
Number of pages3
JournalJournal of Biological Chemistry
Issue number18
Publication statusPublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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