Editors' ChoiceCell Biology

InsP7 and Insulin Release

STKE  27 Nov 2007:
Vol. 2007, Issue 414, pp. tw435
DOI: 10.1126/stke.4142007tw435

Inositol 1,4,5-trisphosphate (IP3) is a well-known second messenger in cellular signaling. More highly phosphorylated forms of this molecule, inositol pyrophosphates, may also function in cellular regulation. Illies et al. (see the Perspective by Nagamatsu and Ohara-Imaizumi) now show that InsP7 (diphosphoinositol pentakisphosphate) is required for full exocytotic release of insulin from mouse pancreatic β cells. Depletion of the kinase that generates InsP7 inhibited exocytosis, whereas overexpression of the enzyme stimulated exocytotic release of insulin. Pancreatic β cells may maintain high amounts of InsP7 to help ensure ready release of insulin in response to metabolic demands.

C. Illies, J. Gromada, R. Fiume, B. Leibiger, J. Yu, K. Juhl, S.-N. Yang, D. K. Barma, J. R. Falck, A. Saiardi, C. J. Barker, P.-O. Berggren, Requirement of inositol pyrophosphates for full exocytotic capacity in pancreatic β cells. Science 318, 1299-1302 (2007). [Abstract] [Full Text]

S. Nagamatsu, M. Ohara-Imaizumi, IP7 debut in insulin release. Science 318, 1249-1250 (2007). [Abstract] [Full Text]