Interplay of Ca2+ and cAMP signaling in the insulin-secreting MIN6 β-cell line

Luis E. Landa, Mark Harbeck, Kelly Kaihara, Oleg Chepurny, Kajorn Kitiphongspattana, Oliver Graf, Viacheslav O. Nikolaev, Martin J. Lohse, George G. Holz, Michael W. Roe

Research output: Contribution to journalArticle

158 Scopus citations

Abstract

Ca2+ and cAMP are important second messengers that regulate multiple cellular processes. Although previous studies have suggested direct interactions between Ca2+ and cAMP signaling pathways, the underlying mechanisms remain unresolved. In particular, direct evidence for Ca 2+-regulated cAMP production in living cells is incomplete. Genetically encoded fluorescence resonance energy transfer-based biosensors have made possible real-time imaging of spatial and temporal gradients of intracellular cAMP concentration in single living cells. Here, we used confocal microscopy, fluorescence resonance energy transfer, and insulin-secreting MIN6 cells expressing Epac1-camps, a biosynthetic unimolecular cAMP indicator, to better understand the role of intracellular Ca2+ in cAMP production. We report that depolarization with high external K+, tolbutamide, or glucose caused a rapid increase in cAMP that was dependent on extracellular Ca2+ and inhibited by nitrendipine, a Ca2+ channel blocker, or 2′,5′-dideoxyadenosine, a P-site antagonist of transmembrane adenylate cyclases. Stimulation of MIN6 cells with glucose in the presence of tetraethylammonium chloride generated concomitant Ca2+ and cAMP oscillations that were abolished in the absence of extracellular Ca2+ and blocked by 2′,5′-dideoxyadenosine or 3-isobutyl-1-methylxanthine, an inhibitor of phosphodiesterase. Simultaneous measurements of Ca2+ and cAMP concentrations with Fura-2 and Epac1-camps, respectively, revealed a close temporal and causal interrelationship between the increases in cytoplasmic Ca2+ and cAMP levels following membrane depolarization. These findings indicate highly coordinated interplay between Ca2+ and cAMP signaling in electrically excitable endocrine cells and suggest that Ca2+-dependent cAMP oscillations are derived from an increase in adenylate cyclase activity and periodic activation and inactivation of cAMP-hydrolyzing phosphodiesterase.

Original languageEnglish (US)
Pages (from-to)31294-31302
Number of pages9
JournalJournal of Biological Chemistry
Volume280
Issue number35
DOIs
StatePublished - Sep 2 2005

Fingerprint Dive into the research topics of 'Interplay of Ca<sup>2+</sup> and cAMP signaling in the insulin-secreting MIN6 β-cell line'. Together they form a unique fingerprint.

  • Cite this

    Landa, L. E., Harbeck, M., Kaihara, K., Chepurny, O., Kitiphongspattana, K., Graf, O., Nikolaev, V. O., Lohse, M. J., Holz, G. G., & Roe, M. W. (2005). Interplay of Ca2+ and cAMP signaling in the insulin-secreting MIN6 β-cell line. Journal of Biological Chemistry, 280(35), 31294-31302. https://doi.org/10.1074/jbc.M505657200