Plasma Membrane Ca2-ATPase Overexpression Reduces Ca2 Oscillations and Increases Insulin Release Induced by Glucose in Insulin-Secreting

In the mouse -cell, glucose generates large amplitude oscillations of the cytosolic-free Ca2 concentration ([Ca2]i) that are synchronous to insulin release oscil-lations. To examine the role played by [Ca2]i oscilla-tions in the process of insulin release, we examined the effect of plasma membrane Ca2-ATPase (PMCA) over-expression on glucose-induced Ca2 oscillations and insulin release in BRIN-BD11 cells. BRIN-BD11 cells were stably transfected with PMCA2wb. Overexpres-sion could be assessed at the mRNA and protein level, with appropriate targeting to the plasma membrane assessed by immunofluorescence and the increase in PMCA activity. In response to K, overexpressing cells showed a markedly reduced rise in [Ca2]i. In response to glucose, control cells showed large amplitude [Ca2]