AKAP 18 alpha and gamma have opposing effects on insulin release in INS-1E cells

A-kinase anchoring proteins (AKAPs) are known to compartmentalise protein kinase(s) to discrete cellular locations. Here we show that silencing of AKAP 18 alpha or gamma expression results in decreased or increased glucose-stimulated insulin secretion in INS-1E cells. Glucose stimulates AKAP 18 alpha and inhibits AKAP 18 gamma mRNA expressions while palmitate markedly reduces AKAP 18 alpha expression. Human growth hormone (GH) stimulates AKAP 18 alpha expression and attenuates palmitate-induced suppression of AKAP 18 alpha mRNA level. The roles of AKAP 18 alpha and gamma in mediating insulin release are consistent with their respective regulations by glucose.