ATP-sensitive inward rectifier potassium channel (KATP) (KATP)

The ATP-sensitive inward rectifier potassium channel (KATP) in pancreatic beta cells is a hetero-octameric protein complex consisting of four pore-forming Kir6.2 subunits (encoded by KCNJ11) and four regulatory sulfonylurea receptor 1 (SUR1) subunits (encoded by ABCC8) [1, 2]. This channel serves as a critical metabolic sensor that couples the intracellular ATP/ADP ratio to the cell's membrane potential [3]. Under high glucose conditions, increased ATP production leads to channel closure, resulting in membrane depolarization, calcium influx, and the subsequent secretion of insulin [2, 4]. Genetic mutations in the KATP channel subunits are primary causes of neonatal diabetes mellitus and congenital hyperinsulinism [5]. The channel is the primary therapeutic target for sulfonylureas and meglitinides, which promote insulin release in type 2 diabetes by inducing channel closure [6]. Conversely, KATP channel openers like diazoxide are utilized to inhibit excessive insulin secretion in hypoglycemic disorders [1].

Other names

ATP-sensitive potassium channelKir6.2/SUR1 complexSulfonylurea receptor 1Inward rectifier potassium channel 6.2KCNJ11/ABCC8 complex

Sulfonylureas and meglitinides bind to the SUR1 subunit of the KATP channel, causing it to close; this leads to membrane depolarization, activation of voltage-gated calcium channels, and insulin exocytosis. KATP channel openers like diazoxide maintain the channel in an open state, hyperpolarizing the cell and inhibiting insulin release.