Creation of an inositol 1,4,5-trisphosphate-sensitive Ca2+ store in secretory granules of insulin-producing cells.
A rapid rise in the cytosolic free Ca2+ concentration due to influx of extracellular Ca2+ or mobilization from intracellular stores is the primary trigger for exocytosis from secretory cells. Our understanding as to the precise role of Ca2+ mobilization has been complicated by the presence of several types of Ca2+ stores in most cells. We now demonstrate that overexpression of the type 3 inositol 1,4,5-trisphosphate (IP3) receptor in insulin-secreting beta TC-3 cells results in the creation of a unique IP3-sensitive Ca2+ pool, restricted to the insulin secretory granules of these cells.
Howard Hughes Medical Institute, University of Chicago, Illinois 60637.
O
O
Blondel
G I
GI
Bell
M
M
Moody
R J
RJ
Miller
S J
SJ
Gibbons
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D002451:Cell Compartmentation; D002478:Cells, Cultured; D003594:Cytoplasmic Granules / Q000378:metabolism; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D014162:Transfection
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007328:Insulin; D018160:Receptors, Cytoplasmic and Nuclear; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D002118:Calcium