ATP-sensitive inward rectifier potassium channel (KATP) complex (KATP channel)

The pancreatic β-cell KATP channel complex is a hetero-octameric protein assembly composed of four pore-forming inward rectifier potassium channel 6.2 (Kir6.2) subunits and four regulatory sulfonylurea receptor 1 (SUR1) subunits (UniProt: Q09428, Q14654). It functions as a critical metabolic sensor that couples intracellular energy levels, specifically the ATP/ADP ratio, to the membrane potential of the β-cell (PubMed: 28114273). Under high glucose conditions, increased ATP levels lead to channel closure, resulting in membrane depolarization, calcium influx, and the subsequent exocytosis of insulin (StatPearls: NBK537105). Dysregulation of this complex is central to various glycemic disorders; gain-of-function mutations cause neonatal diabetes, while loss-of-function mutations lead to congenital hyperinsulinism (PubMed: 16150867). Therapeutic agents like sulfonylureas and glinides target the SUR1 subunit to stimulate insulin secretion in type 2 diabetes patients, whereas potassium channel openers like diazoxide are used to suppress insulin release in hyperinsulinemic states (PubChem: CID 3133).

Other names

Sulfonylurea receptor 1-Kir6.2 complexPancreatic beta-cell KATP channelABCC8-KCNJ11 complexSUR1-Kir6.2 channel

Sulfonylureas and glinides bind to the SUR1 subunit, inducing channel closure, membrane depolarization, and insulin release. Diazoxide binds to SUR1 to maintain the channel in an open state, causing hyperpolarization and inhibiting insulin release.