Inward-rectifier potassium ion channel


Inwardly rectifying potassium channels (Kir, IRK) are a specific subset of potassium (K) selective ion channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are the targets of multiple toxins, and malfunction of the channels has been implicated in several diseases. IRK channels possess a pore domain, homologous to that of voltage-gated ion channels, and flanking transmembrane segments (TMSs). They may exist in the membrane as homo- or heterooligomers and each monomer possesses between 2 and 4 TMSs. In terms of function, these proteins transport potassium (K), with a greater tendency for K uptake than K export.