KCNJ1
Function
Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. This channel is activated by internal ATP and can be blocked by external barium. In the kidney, probably plays a major role in potassium homeostasis.
Involvement in disease
Bartter syndrome 2, antenatal
BARTS2
A form of Bartter syndrome, an autosomal recessive disorder characterized by impaired salt reabsorption in the thick ascending loop of Henle with pronounced salt wasting, hypokalemic metabolic alkalosis, and varying degrees of hypercalciuria. BARTS2 is a life-threatening condition beginning in utero, with marked fetal polyuria that leads to polyhydramnios and premature delivery. Another hallmark is a marked hypercalciuria and, as a secondary consequence, the development of nephrocalcinosis and osteopenia.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Phosphorylation at Ser-44 by SGK1 is necessary for its expression at the cell membrane.
Sequence Similarities
Belongs to the inward rectifier-type potassium channel (TC 1.A.2.1) family. KCNJ1 subfamily.
Tissue Specificity
In the kidney and pancreatic islets. Lower levels in skeletal muscle, pancreas, spleen, brain, heart and liver.
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Phosphorylation at Ser-44 by SGK1 is necessary for its expression at the cell membrane.
Alternative names
ROMK1, KCNJ1, ATP-sensitive inward rectifier potassium channel 1, ATP-regulated potassium channel ROM-K, Inward rectifier K(+) channel Kir1.1