ATP-Sensitive Potassium Channel Receptor (K_ATP channel)

The ATP-sensitive potassium (K_ATP) channel is a crucial membrane protein complex that links cellular metabolic state to membrane excitability. It is an octameric complex composed of four inward-rectifier potassium channel subunits (Kir6.x; either Kir6.1 or Kir6.2) and four sulfonylurea receptor (SUR) subunits (SUR1, SUR2A, or SUR2B). The channel translates changes in the intracellular ATP/ADP ratio into alterations in potassium ion flux across the cell membrane, thereby modulating electrical activity in various tissues. High intracellular ATP binds to Kir6.x and closes the channel, while MgADP binds to SUR and promotes channel opening. The tissue distribution and subunit composition determine its specific physiological roles, such as regulating insulin secretion in pancreatic β-cells, protecting against ischemia in cardiomyocytes, and regulating vascular tone in vascular smooth muscle. Mutations in K_ATP channel subunits can cause diseases such as congenital hyperinsulinism or neonatal diabetes. Sulfonylureas, which bind to SUR1 on pancreatic channels, are used as antidiabetic agents.

Other names

KATP channelATP-sensitive K+ channel

Sulfonylureas bind to SUR1, closing the channel and stimulating insulin release.