In a recent study we discovered that a rare lipid in the outer membrane of b-cells plays a critical role in regulating the amount of calcium that enters the b-cell and, in extension, also the amount of insulin that these cells release. Experimental removal of this lipid by an optogenetic approach almost completely abolished calcium entry and strongly suppressed insulin release.
A lipid that control insulin secretion
Insulin secretion from pancreatic b-cells occurs in response to increased blood glucose levels and failure to secrete this hormone is a hallmark of diabetes. The exact mechnism linking glucose sensing to insulin secretion is not fully understood, but a key step is the triggered influx of calcium ions, that in turn stimulate the release of insulin-containing vesicles. In a recent study (1) we discovered that a rare lipid in the outer membrane of b-cells plays a critical role in regulating the amount of calcium that enters the b-cell and, in extension, also the amount of insulin that these cells release. Experimental removal of this lipid by an optogenetic approach almost completely abolished calcium entry and strongly suppressed insulin release. This lipid is under strict metabolic control, and we are currently investigating to what extent this lipid is affected by disease conditions characterized by altered metabolism, such as diabetes.
(1) Plasma Membrane Phosphatidylinositol 4,5-Bisphosphate Regulates Ca2+-Influx and Insulin Secretion from Pancreatic β Cells.
Xie B, Nguyen PM, Guček A, Thonig A, Barg S, Idevall-Hagren O.
Cell Chem Biol. 2016 Jul 21;23(7):816-826.
http://www.cell.com/cell-chemical-biology/fulltext/S2451-9456(16)30202-1
See also the preview that accompanied the paper: http://www.cell.com/cell-chemical-biology/fulltext/S2451-9456(16)30208-2