Persistence of the interaction of calmodulin with adenylyl cyclase: Implications for integration of transient calcium stimuli

Chiadi U. Onyike, Allison H. Lin, Thomas W. Abrams

Research output: Contribution to journalArticle


Ca2+/calmodulin-sensitive adenylyl cyclase plays a role in several forms of synaptic plasticity and learning. To understand how cellular signals from neuronal activity during behavioral stimuli might be integrated by adenylyl cyclase, we have characterized the response of type I adenylyl cyclase to transient Ca2+ stimuli. Stimulation by a several second Ca2+ stimulus is delayed, rising to a peak after the Ca2+ stimulus has ended. We attempted to identify the site of the persistent Ca2+ signal that enabled adenylyl cyclase stimulation to increase after free Ca2+ had declined. Free calmodulin itself displayed no persistent activation by Ca2+ and was unable to activate adenylyl cyclase if exposed to low Ca2+ solution <1 s before reaching adenylyl cyclase. In contrast, activation of the calmodulin-adenylyl cyclase complex persisted for seconds after Ca2+ stimulus. Activation decayed with a time constant of 6 or 13 s depending on assay conditions. These results suggest that the calmodulin-adenylyl cyclase complex can serve as a site of cellular memory for a Ca2+ transient that has ended even before adenylyl cyclase is fully activated.

Original languageEnglish (US)
Pages (from-to)1298-1306
Number of pages9
JournalJournal of Neurochemistry
Issue number3
StatePublished - Sep 1 1998
Externally publishedYes



  • Adenylyl cyclase
  • Associative learning
  • Ca
  • Calmodulin
  • Coincidence detector
  • Synaptic plasticity
  • Transient Ca stimuli

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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