The insulin-like growth factor II (IGF-II)/mannose-6-phosphate (M-6-P) receptor is known to participate in endocytosis as well as sorting of lysosomal enzymes and is involved in membrane trafficking through rapid cycling between cytosolic membrane compartments and the plasma membrane. Here we demonstrate that IGF-II, acting through the IGF-II/M-6-P receptor, promotes exocytosis of insulin in the pancreatic β cell. The effect of IGF- II was evoked at nonstimulatory concentrations of glucose, was mediated by a pertussis toxin sensitive GTP-binding protein, was dependent on protein kinase C-induced phosphorylation, and was independent of changes in cytoplasmic free Ca2+ concentration. Since the applied concentration of IGF-II is within the range normally found free in circulation in humans, this novel signaling pathway for the IGF-II/M-6-P receptor is likely to be involved in modulation of insulin exocytosis under physiological conditions.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jun 10 1997|
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