Integration of ATP, cAMP, and Ca2+ signals in insulin granule exocytosis

Diabetes. 2004 Dec:53 Suppl 3:S59-62. doi: 10.2337/diabetes.53.suppl_3.s59.

Abstract

Intracellular ATP, cAMP, and Ca2+ are major signals involved in the regulation of insulin secretion in the pancreatic beta-cell. We recently found that the ATP-sensitive K+ channel (KATP channel) as an ATP sensor, cAMP-GEFII as a cAMP sensor, Piccolo as a Ca2+ sensor, and L-type voltage-dependent Ca2+ channel (VDCC) can interact with each other. In the present study, we examined the effects of cAMP and ATP on the interaction of cAMP-GEFII and sulfonylurea receptor-1 (SUR1). Interaction of cAMP-GEFII with SUR1 was inhibited by the cAMP analog 8-bromo-cAMP but not by ATP, and the inhibition by 8-bromo-cAMP persisted in the presence of ATP. In addition, SUR1, cAMP-GEFII, and Piccolo could form a complex. Piccolo also interacted with the alpha1 1.2 subunit of VDCC in a Ca2+-independent manner. These data suggest that the interactions of the KATP channel, cAMP-GEFII, Piccolo, and L-type VDCC are regulated by intracellular signals such as cAMP and Ca2+ and that the ATP, cAMP, and Ca2+ signals are integrated at a specialized region of pancreatic beta-cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / physiology*
  • Animals
  • Calcium Channels / physiology*
  • Cell Line
  • Cyclic AMP / physiology*
  • Cytoplasmic Granules / physiology*
  • Exocytosis / physiology*
  • Insulin / metabolism*
  • Insulin Secretion
  • Islets of Langerhans / metabolism
  • Islets of Langerhans / physiology
  • Mice
  • Signal Transduction / physiology*

Substances

  • Calcium Channels
  • Insulin
  • Adenosine Triphosphate
  • Cyclic AMP