KCNJ1 Gene: Potassium Channel, Bartter Syndrome, and Renal Function

KCNJ1 encodes the ROMK (Kir1.1) potassium channel, a member of the inward rectifier potassium channel family. It is primarily expressed in the kidney, where it mediates potassium recycling in the thick ascending limb of Henle's loop and potassium secretion in the collecting duct. ROMK is essential for maintaining electrolyte homeostasis and urine concentration. Mutations in KCNJ1 cause Bartter syndrome type 2, a renal tubular disorder characterized by salt wasting, hypokalemia, and metabolic alkalosis.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Renal cell potassium transport

• Bartter syndrome pathway

• Inward rectifier potassium channels

The ROMK protein (UniProt P48048) is a 391-amino acid integral membrane protein with two transmembrane domains and a pore-forming loop. It forms homotetrameric channels that conduct potassium ions into cells in an inwardly rectifying manner. ROMK is regulated by intracellular pH, ATP, and phosphorylation. In the kidney, it localizes to the apical membrane of thick ascending limb and collecting duct cells, where it facilitates potassium recycling and secretion.