Diabetes 53:S92-S95, 2004 © 2004 by the American Diabetes Association, Inc.
Nutrients Induce Different Ca2+ Signals in Cytosol and Nucleus in Pancreatic ß-Cells
1 Department of Bioengineering, University of Washington, Seattle, Washington
Specific activation of Ca2+-dependent functions is achieved by the particular dynamics and local restriction of Ca2+ signals. It has been shown that changes in amplitude, duration, or frequency of Ca2+ signals modulate gene transcription. Thus, Ca2+ variations should be finely controlled within the nucleus. Although a variety of mechanisms in the nuclear membrane have been demonstrated to regulate nuclear Ca2+, the existence of an autonomous Ca2+ homeostasis within the nucleus is still questioned. In the pancreatic ß-cell, besides their effect on insulin secretion, Ca2+ messages generated by nutrients also exert their action on gene expression. However, the dynamics of these Ca2+ signals in relation to nuclear function have been explored little in islet cells. In the current study, Ca2+ changes both in the nucleoplasm and in the cytosol of INS-1 and pancreatic ß-cells were monitored using spot confocal microscopy. We show that nutrients trigger Ca2+ signals of higher amplitude in the nucleus than in the cytosol. These amplitude-modulated Ca2+ signals transmitted to the nucleus might play an important role in the control of gene expression in the pancreatic ß-cell.
Address correspondence and reprint requests to Bernat Soria, MD, Institute of Bioengineering, Miguel Hernandez University, San Juan Campus, Carretera Alicante-Valencia Km 87, 03550 Alicante, Spain. E-mail: bernat.soria{at}umh.es
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