KCNJ8

KCNJ8 is a gene that encodes the protein Kir6.1, a subunit of the ATP-sensitive potassium (K_ATP) channel. This channel is found in the smooth muscle of various tissues, including the heart and blood vessels, and plays a crucial role in the regulation of vascular tone and blood flow.

Structure

The KCNJ8 gene is located on the short (p) arm of chromosome 12 at position 12.2. It spans about 23.5 kilobases and consists of two exons. The encoded protein, Kir6.1, is a member of the inward rectifier-type potassium channel family, which includes seven other members. Kir6.1 has two transmembrane domains, an intracellular N- and C-terminus, and a pore region that is selective for potassium ions.

Function

The primary function of Kir6.1 is to form the pore of the K_ATP channel. This channel is a hetero-octameric complex composed of four Kir6.x subunits and four regulatory sulfonylurea receptor (SUR) subunits. The K_ATP channel is sensitive to changes in the intracellular ATP/ADP ratio and helps to couple the metabolic state of cells to their electrical activity. In response to a decrease in the ATP/ADP ratio, the K_ATP channel opens, leading to hyperpolarization of the cell membrane and inhibition of electrical activity.

Clinical significance

Mutations in the KCNJ8 gene have been associated with various medical conditions. For example, a specific mutation (T158A) has been linked to Cantú syndrome, a rare genetic disorder characterized by hypertrichosis, distinctive facial features, and cardiac anomalies. Other mutations in KCNJ8 have been implicated in the development of hypertension and type 2 diabetes.

See also

• Inward rectifier potassium ion channels
• ATP-sensitive potassium channel
• Cantú syndrome
• Hypertension
• Type 2 diabetes