Kir2.2v: a possible negative regulator of the inwardly rectifying K+ channel Kir2.2

Abstract
We have cloned the human genes encoding the inwardly rectifying K+ (Kir) channel subunits, Kir2.2 (hKir2.2) and its variant, termed hKir2.2v. When expressed in Xenopus oocytes, hKir2.2 produced strong inwardly rectifying K+ currents, whereas the expression of hKir2.2v did not elicit significant currents. Coexpression of hKir2.2v with hKir2.2 showed an hKir2.2v inhibition of hKir2.2 K+ currents, indicating that it acts as a negative regulator of hKir2.2 channel activity. Mutational analysis of hKir2.2v and studies of chimeras between hKir2.2 and hKir2.2v suggest that the intracellular C‐terminal region of hKir2.2v participates in the negative regulation of the hKir2.2v channel activity.