Regulation of PKD by the MAPK p38delta in insulin secretion and glucose homeostasis.
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Sumara G, Formentini I, Collins S, Sumara I, Windak R, Bodenmiller B, Ramracheya R, Caille D, Jiang H, Platt KA, Meda P, Aebersold R, Rorsman P, Ricci R
Regulation of PKD by the MAPK p38delta in insulin secretion and glucose homeostasis.
Cell. 2009 Jan 23;136(2):235-48. doi: 10.1016/j.cell.2008.11.018. Epub 2009 Jan 8.
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- 19135240 [ View in PubMed]
- Abstract
Dysfunction and loss of insulin-producing pancreatic beta cells represent hallmarks of diabetes mellitus. Here, we show that mice lacking the mitogen-activated protein kinase (MAPK) p38delta display improved glucose tolerance due to enhanced insulin secretion from pancreatic beta cells. Deletion of p38delta results in pronounced activation of protein kinase D (PKD), the latter of which we have identified as a pivotal regulator of stimulated insulin exocytosis. p38delta catalyzes an inhibitory phosphorylation of PKD1, thereby attenuating stimulated insulin secretion. In addition, p38delta null mice are protected against high-fat-feeding-induced insulin resistance and oxidative stress-mediated beta cell failure. Inhibition of PKD1 reverses enhanced insulin secretion from p38delta-deficient islets and glucose tolerance in p38delta null mice as well as their susceptibility to oxidative stress. In conclusion, the p38delta-PKD pathway integrates regulation of the insulin secretory capacity and survival of pancreatic beta cells, pointing to a pivotal role for this pathway in the development of overt diabetes mellitus.