Document Detail

Extracellular Calcium influx activates Adenylate Cyclase 1 and potentiates Insulin secretion in MIN6 cells.
MedLine Citation:
PMID:  23282092     Owner:  NLM     Status:  Publisher    
Intracellular cAMP and Ca2+ 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 this study, we investigated the interplay between intracellular cAMP and Ca2+ concentrations ([cAMP]i and [Ca2+]i, respectively) in the pancreatic β cell line MIN6 cells using total internal reflection fluorescence microscopy. For measuring [cAMP]i, we developed a genetically encoded yellow fluorescent biosensor for cAMP (fluorescent cAMP indicator; Flamindo), 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 Ca2+ channel agonist or ionomycin to induce extracellular Ca2+ influx evoked the elevation of [cAMP]i, whereas application of carbachol or thapsigargin, which mobilize Ca2+ from internal stores, did not evoke the elevation of [cAMP]i. We performed RT-PCR analysis and found that Ca2+-sensitive adenylate cyclase 1 (Adcy1) 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 [Ca2+]i. Taken together, these findings demonstrate that Adcy1 plays an important role in the control of pancreatic β cell cAMP homeostasis and insulin secretion.
Tetsuya Kitaguchi; Manami Oya; Yoshiko Wada; Takashi Tsuboi; Atsushi Miyawaki
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-3
Journal Detail:
Title:  The Biochemical journal     Volume:  -     ISSN:  1470-8728     ISO Abbreviation:  Biochem. J.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-3     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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