Leucine culture reveals that ATP synthase functions as a fuel sensor in pancreatic beta-cells. J Biol Chem 2004 Dec 24;279(52):53915-23
Date
10/19/2004Pubmed ID
15489222DOI
10.1074/jbc.M405309200Scopus ID
2-s2.0-19944426266 (requires institutional sign-in at Scopus site) 31 CitationsAbstract
Our goal was to investigate whether leucine culture affects beta-cell glucose sensing. One-day culture of rat islets with 10 mM leucine had no effect on glucose-induced insulin secretion. One-week leucine culture decreased the threshold for glucose-induced insulin secretion and increased maximal insulin secretion at 30 mM glucose. Glucose-induced cytosolic free Ca(2+) was increased at 1 week but not at 1 day of leucine culture. Without glucose, ATP content was not different with or without leucine culture for 1 week. With 20 mM glucose, ATP content was higher by 1.5-fold in islets cultured for 1 week with leucine than those without leucine. Microarray experiments indicated that culture of RINm5F cells with leucine increased expression of ATP synthase beta subunit 3.2-fold, which was confirmed by real time reverse transcription-PCR analysis (3.0- +/- 0.4-fold) in rat islets at 1 week but not after 1 day with leucine culture. Down-regulation of ATP synthase beta subunit by siRNA decreased INS1 cell ATP content and insulin secretion with 20 mM glucose. Overexpression of ATP synthase beta subunit in INS1 cell increased insulin secretion in the presence of 5 and 20 mM glucose. In conclusion, one-week leucine culture of rat islets up-regulated ATP synthase and increased ATP content, which resulted in elevated [Ca(2+)] levels and more insulin exocytosis by glucose. Depletion of ATP synthase beta subunit with siRNA produced opposite effects. These data reveal the fuel-sensing role of mitochondrial ATP synthase in the control of ATP production from glucose and the control of glucose-induced insulin secretion.
Author List
Yang J, Wong RK, Wang X, Moibi J, Hessner MJ, Greene S, Wu J, Sukumvanich S, Wolf BA, Gao ZAuthor
Martin J. Hessner PhD Professor in the Pediatrics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Adenosine TriphosphateAnimals
Calcium
Cell Line
Cells, Cultured
Cytosol
Glucose
Humans
Insulin
Islets of Langerhans
Leucine
Male
Mitochondrial Proton-Translocating ATPases
RNA, Small Interfering
Rats
Rats, Sprague-Dawley
Reverse Transcriptase Polymerase Chain Reaction
Transfection