Nutrients induce different Ca(2+) signals in cytosol and nucleus in pancreatic beta-cells.
Specific activation of Ca(2+)-dependent functions is achieved by the particular dynamics and local restriction of Ca(2+) signals. It has been shown that changes in amplitude, duration, or frequency of Ca(2+) signals modulate gene transcription. Thus, Ca(2+) variations should be finely controlled within the nucleus. Although a variety of mechanisms in the nuclear membrane have been demonstrated to regulate nuclear Ca(2+), the existence of an autonomous Ca(2+) homeostasis within the nucleus is still questioned. In the pancreatic beta-cell, besides their effect on insulin secretion, Ca(2+) messages generated by nutrients also exert their action on gene expression. However, the dynamics of these Ca(2+) signals in relation to nuclear function have been explored little in islet cells. In the current study, Ca(2+) 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 Ca(2+) signals of higher amplitude in the nucleus than in the cytosol. These amplitude-modulated Ca(2+) signals transmitted to the nucleus might play an important role in the control of gene expression in the pancreatic beta-cell.
Quesada
Ivan
I
Department of Bioengineering, University of Washington, Seattle, Washington, USA.
Martin
Franz
F
Roche
Enrique
E
Soria
Bernat
B
D018528:ATP-Binding Cassette Transporters; D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D002467:Cell Nucleus / Q000502:physiology*; D002478:Cells, Cultured; D003600:Cytosol / Q000502:physiology; D007515:Islets of Langerhans / Q000166:cytology / Q000502:physiology*; D054086:KATP Channels; D008297:Male; D051379:Mice; D018613:Microscopy, Confocal; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying; D014044:Tolbutamide / Q000494:pharmacology
D018528:ATP-Binding Cassette Transporters; D054086:KATP Channels; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; C092520:uK-ATP-1 potassium channel; D014044:Tolbutamide