Sulfonylurea Receptor (SUR)

The sulfonylurea receptor (SUR) is a membrane protein that serves as the molecular target for sulfonylurea class antidiabetic drugs. These drugs promote insulin release from pancreatic beta cells by modulating the activity of ATP-sensitive potassium (K(ATP)) channels. SURs are part of the ATP-binding cassette (ABC) transporter family, but unlike typical ABC transporters, they act as regulatory subunits for ion channels. SURs regulate opening/closing of associated K(ATP) channels. High intracellular ATP closes these channels via binding to nucleotide-binding domains (NBDs) on SUR, which leads to cell depolarization and triggers downstream effects like insulin secretion in pancreatic β-cells or neuroprotection in neurons during ischemia. It interacts with Kir6.x and TRPM4 to form complexes and different isoforms exists, including SUR1 (ABCC8), SUR2A and SUR2B (ABCC9).

Inhibition of KATP channels, leading to increased insulin secretion