The physiological role of the inwardly rectifying potassium channel, Kir5. 1, is poorly
understood, as is the molecular identity of many renal potassium channels. In this study we
have used Kir5. 1-specific antibodies to reveal abundant expression of Kir5. 1 in renal
tubular epithelial cells, where Kir4. 1 is also expressed. Moreover, we also show that Kir5.
1/Kir4. 1 heteromeric channel activity is extremely sensitive to inhibition by intracellular
acidification and that this novel property is conferred predominantly by the Kir5. 1 subunit …