ATP-sensitive potassium channel (KATP channel) (K₊TP channel)

The ATP-sensitive potassium channel (K₊TP channel), composed of Kir6.2 and SUR1 subunits in pancreatic β-cells, serves as a key metabolic sensor that couples glucose levels to insulin secretion. At low glucose, open channels maintain hyperpolarization, suppressing Ca⁺² influx and insulin release; rising glucose boosts ATP/ADP ratios via glycolysis, closing channels to depolarize the membrane, activate voltage-gated Ca⁺² channels, and trigger insulin exocytosis in a biphasic manner. This glucose-stimulated insulin secretion (GSIS) mechanism is central to glucose homeostasis, with channel dysfunction implicated in diabetes: activating mutations cause neonatal diabetes by preventing closure, while impaired β-cell metabolism in type 2 diabetes reduces ATP generation and channel sensitivity. Therapeutically, sulfonylureas and meglitinides close K₊TP channels to enhance insulin release in diabetes management, though this risks hypoglycemia. Emerging insights highlight its role in oscillatory electrical activity and potential contributions to glucagon regulation in α-cells, underscoring its broad impact on islet function.

Other names

K₊TP channelATP-sensitive K⁺ channelKir6.2/SUR1 channel (pancreatic β-cell isoform)

Channel closure by increased ATP/ADP ratio from glucose metabolism, leading to depolarization, voltage-gated Ca⁺² channel opening, and insulin granule exocytosis Pharmacological closure by sulfonylureas binding to SUR1 subunit, mimicking ATP effect to promote insulin release