Sulfonylurea receptor 1-containing ATP-sensitive potassium channel complex (SUR1-KATP channel)

The SUR1-containing KATP channel complex is an octameric protein assembly composed of four pore-forming inwardly rectifying potassium channel subunits (Kir6.2, encoded by KCNJ11) and four regulatory sulfonylurea receptor 1 subunits (SUR1, encoded by ABCC8). Primarily expressed in pancreatic beta cells and specific hypothalamic neurons, this complex acts as a metabolic sensor by coupling the intracellular ATP/ADP ratio to membrane excitability. When glucose levels rise, increased ATP production leads to channel closure, triggering membrane depolarization, calcium influx, and the exocytosis of insulin. In pathological states, mutations in the subunits can lead to either overactivity (causing neonatal diabetes) or underactivity (causing congenital hyperinsulinism). Beyond the pancreas, the SUR1 subunit can also associate with TRPM4 channels in the vascular endothelium and astrocytes following central nervous system injury, where it contributes to the formation of cerebral edema and is a target for neuroprotective interventions.

Other names

ABCC8-KCNJ11 complexPancreatic ATP-sensitive potassium channelKir6.2/SUR1 channelSulfonylurea receptor 1-inwardly rectifying potassium channel 6.2 complex

Sulfonylureas and glinides act as agonists of the SUR1 subunit, leading to the closure of the KATP channel, membrane depolarization, and subsequent insulin release. Conversely, potassium channel openers like diazoxide bind to SUR1 to maintain the channel in an open state, hyperpolarizing the cell and inhibiting insulin secretion. In the context of CNS injury, SUR1 inhibitors prevent the non-selective cation flux through SUR1-TRPM4 channels that contributes to cerebral edema.