Kir6.2

Kir6.2 is a protein that in humans is encoded by the KCNJ11 gene. It is a subunit of the potassium channel, specifically the inward-rectifier type. This protein forms a part of the ATP-sensitive potassium channel, which is found in the plasma membrane of many cell types and controls the flow of potassium ions in and out of the cells.

Structure[edit | edit source]

The Kir6.2 protein is composed of 390 amino acids and has a molecular weight of approximately 43.4 kDa. It has two transmembrane domains with the N- and C-termini located on the intracellular side of the membrane. The protein also contains a pore-forming region between the two transmembrane domains.

Function[edit | edit source]

The primary function of Kir6.2 is to form a part of the ATP-sensitive potassium channel. This channel is a complex of four Kir6.2 subunits and four sulfonylurea receptor (SUR) subunits. The channel is sensitive to the levels of ATP and ADP in the cell. When ATP levels are high, the channel closes, preventing potassium ions from leaving the cell. When ATP levels drop and ADP levels rise, the channel opens, allowing potassium ions to flow out of the cell. This mechanism helps to regulate the electrical activity of the cell.

Clinical significance[edit | edit source]

Mutations in the KCNJ11 gene that encodes Kir6.2 can lead to several diseases. These include permanent neonatal diabetes mellitus, transient neonatal diabetes mellitus, and hyperinsulinemic hypoglycemia. These diseases are all related to the regulation of insulin secretion by pancreatic beta cells, which is controlled by the ATP-sensitive potassium channel.