Nutrients induce different Ca2+ signals in cytosol and nucleus in pancreatic β-cells

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 mechanisins 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 beta-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+ sig nals 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 beta-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 beta-cell. Diabetes 53 (Suppl. 1):S92-S95, 2004.