ATP-sensitive potassium channel regulatory subunit sulfonylurea receptor 1 (SUR1)

ATP-sensitive potassium channel regulatory subunit sulfonylurea receptor 1 (SUR1) is a large transmembrane protein encoded by the ABCC8 gene. It belongs to the atypical ABC transporter family but does not function as a classical transporter; instead, it acts as a regulatory subunit for ion channels—most notably forming part of octameric complexes with Kir6.x pore-forming units that constitute KATP channels. These channels couple cellular metabolic state with electrical activity by sensing intracellular ATP/ADP ratios. In pancreatic beta cells, closure of these channels following increased glucose metabolism triggers insulin secretion—a process targeted therapeutically by antidiabetic drugs like glibenclamide and glipizide that bind directly to SUR1. In neurons and other tissues such as heart and endothelium, SUR1-containing channels play roles in protecting against metabolic stress but can also contribute pathologically under certain conditions like stroke or trauma. Mutations affecting SUR1 function are implicated in diseases ranging from congenital hyperinsulinism to various forms of diabetes mellitus. The protein is widely expressed across pancreas, brain, heart, and other tissues.

Other names

Sulfonylurea receptor 1ABCC8 (gene name)KATP channel regulatory subunit SUR1

Drugs such as sulfonylureas bind to SUR1 and inhibit the KATP channel. This inhibition leads to membrane depolarization, opening of voltage-dependent calcium channels, increased intracellular calcium, and subsequent exocytosis of insulin granules from pancreatic beta cells. In the brain, blockade can reduce cerebral edema by inhibiting pathological ion fluxes during ischemia.