Extracellular calcium influx activates adenylate cyclase 1 and potentiates insulin secretion in MIN6 cells

Biochem J. 2013 Mar 1;450(2):365-73. doi: 10.1042/BJ20121022.


Intracellular cAMP and Ca(2+) are important second messengers that regulate insulin secretion in pancreatic β-cells; however, the molecular mechanism underlying their mutual interaction for exocytosis is not fully understood. In the present study, we investigated the interplay between intracellular cAMP and Ca(2+) concentrations ([cAMP](i) and [Ca(2+)](i) respectively) in the pancreatic β-cell line MIN6 using total internal reflection fluorescence microscopy. For measuring [cAMP](i), we developed a genetically encoded yellow fluorescent biosensor for cAMP [Flamindo (fluorescent cAMP indicator)], which changes fluorescence intensity with cAMP binding. Application of high-KCl or glucose to MIN6 cells induced the elevation of [cAMP](i) and exocytosis. Furthermore, application of an L-type Ca(2+) channel agonist or ionomycin to induce extracellular Ca(2+) influx evoked the elevation of [cAMP](i), whereas application of carbachol or thapsigargin, which mobilize Ca(2+) from internal stores, did not evoke the elevation of [cAMP](i). We performed RT (reverse transcription)-PCR analysis and found that Ca(2+)-sensitive Adcy1 (adenylate cyclase 1) was expressed in MIN6 cells. Knockdown of endogenous ADCY1 by small interference RNA significantly suppressed glucose-induced exocytosis and the elevation of both [cAMP](i) and [Ca(2+)](i). Taken together, the findings of the present study demonstrate that ADCY1 plays an important role in the control of pancreatic β-cell cAMP homoeostasis and insulin secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylyl Cyclases / genetics
  • Adenylyl Cyclases / metabolism*
  • Animals
  • COS Cells
  • Calcium / metabolism*
  • Calcium Signaling
  • Cells, Cultured
  • Chlorocebus aethiops
  • Cyclic AMP / metabolism
  • Glucose / metabolism
  • Insulin / metabolism*
  • Insulin Secretion
  • Mice
  • Transfection


  • Insulin
  • Cyclic AMP
  • Adenylyl Cyclases
  • adenylyl cyclase 1
  • Glucose
  • Calcium