A glycolytic enzyme complex and creatine kinase locally and differentially regulate ATP-sensitive potassium (KATP) channels in pancreatic islet alpha and beta cells

Abstract

The ATP-sensitive potassium channel (KATP) is a key regulator of membrane potential and islet hormone secretion. Here, using the inside-out excised patch configuration, we isolated the plasma membrane compartment containing KATP on β-cells and α-cells from humans and mice. The characteristic response of KATP to inhibition by ATP and activation by ADP was used to identify the presence of a glycolytic enzyme complex that is functionally coupled to KATP regulation. We found that the phosphofructokinase product fructose-1,6-bisphosphate (FBP), which oscillates in β-cells, can induce KATP closure by its metabolism through the glycolytic chain including aldolase, GAPDH, phosphoglycerate kinase, phosphoglycerate mutase, enolase and finally pyruvate kinase.