Pancreatic beta-cell ATP-sensitive potassium channel (KATP channel) (KATP channel)

The pancreatic beta-cell ATP-sensitive potassium (KATP) channel is a hetero-octameric protein complex that serves as a metabolic sensor, coupling the energy state of the cell to its electrical activity [1, 5]. It consists of four pore-forming inwardly rectifying potassium channel 6.2 (Kir6.2) subunits and four regulatory sulfonylurea receptor 1 (SUR1) subunits [3, 9]. Under high-glucose conditions, the resulting increase in the intracellular ATP/ADP ratio triggers channel closure, leading to membrane depolarization, calcium influx, and insulin exocytosis [6, 7]. This channel is a critical therapeutic target; sulfonylureas and meglitinides act as inhibitors to stimulate insulin secretion in type 2 diabetes, while diazoxide acts as an opener to treat hyperinsulinism [2, 5]. Genetic mutations in the KCNJ11 or ABCC8 genes, which encode the channel subunits, are linked to disorders such as neonatal diabetes and congenital hyperinsulinism [3, 11]. Proper regulation of this channel is essential for maintaining glucose homeostasis and preventing metabolic dysfunction [4, 13]. The channel's sensitivity to nucleotides and pharmacological agents is primarily mediated by the SUR1 subunits, which contain two nucleotide-binding domains [5, 7]. Therapeutic challenges include the risk of hypoglycemia and potential loss of drug efficacy over time due to beta-cell exhaustion [6, 13].

Other names

Kir6.2/SUR1 complexATP-sensitive potassium channelKATP channelSulfonylurea receptor 1/Inwardly rectifying potassium channel 6.2 complex

Drugs targeting this channel either inhibit or activate its conductance to modulate insulin secretion. Inhibitors, such as sulfonylureas and meglitinides, bind to the SUR1 subunit to close the channel, inducing membrane depolarization and insulin release [2, 5]. Conversely, channel openers like diazoxide maintain the channel in an open state, leading to hyperpolarization and the inhibition of insulin secretion [5, 7].