Plasma Membrane Phosphatidylinositol 4,5-Bisphosphate Regulates Ca2+-Influx and Insulin Secretion from Pancreatic beta Cells

• Insulin secretion from pancreatic beta cells is regulated by the blood glucose concentration and occurs through Ca2+-triggered exocytosis. The activities of multiple ion channels in the beta cell plasma membrane are required to fine-tune insulin secretion in order to maintain normoglycemia. Phosphoinositide lipids in the plasma membrane often gate ion channels, and variations in the concentration of these lipids affect ion-channel open probability and conductance. Using light-regulated synthesis or depletion of plasma membrane phosphatidylinositol 4,5-bisphosphate (PI[4,5]P-2), we found that this lipid positively regulated both depolarization- and glucose-triggered Ca2+ influx in a dose-dependent manner. Small reductions of PI(4,5)P-2 caused by brief illumination resulted in partial suppression of Ca2+ influx that followed the kinetics of the lipid, whereas depletion resulted in marked inhibition of both Ca2+ influx and insulin secretion.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)