Sulfonylurea receptor 1 subunit (SUR1)

The **sulfonylurea receptor 1 (SUR1) subunit** is the regulatory component of the pancreatic ATP-sensitive potassium (KATP) channel, encoded by the *ABCC8* gene. It couples cellular metabolism to membrane excitability in pancreatic beta cells by sensing the ATP/ADP ratio: high intracellular ATP inhibits channel activity (via the Kir6.2 partner), leading to membrane depolarization and insulin secretion, whereas MgADP binding to SUR1 reverses inhibition, opening the channel and suppressing insulin release[1][2][5][6]. Clinically, SUR1 is a key therapeutic target for type 2 diabetes drugs (sulfonylureas, meglitinides) that bind the subunit and promote insulin secretion by closing the KATP channel. Diazoxide, in contrast, is a KATP channel opener used in conditions of excess insulin secretion[5]. Mutations in SUR1 cause inherited forms of insulin dysregulation, including neonatal diabetes and congenital hyperinsulinism[1][5]. The KATP channel is an octameric complex (4 SUR1 + 4 Kir6.2) localized to pancreatic beta cell membranes and, to a lesser extent, the brain[5][6]. The structure and regulatory mechanisms of SUR1 have been resolved with recent advances in cryo-EM, highlighting its essential role as a drug target and metabolic sensor[2][6].

Other names

Sulfonylurea receptor type 1ABCC8 (ATP-binding cassette sub-family C member 8)ATP-sensitive potassium channel regulatory subunit SUR1Pancreatic KATP channel subunit SUR1KATP channel regulatory subunit SUR1

Sulfonylureas inhibit the SUR1 subunit to close the KATP channel, causing cell depolarization and insulin release[1][3][5]. Diazoxide and other KATP channel openers activate the channel via SUR1, stabilizing the open state and inhibiting insulin secretion[5]. Experimental photo-switchable drugs can modulate SUR1 activity with light, providing spatiotemporal control of insulin release[3].