Kir3.4 is a member of the G-protein regulated inward-rectifier K+ (GIRK) channel subfamily which is part of an inward-rectifier K+ channel superfamily. The GIRK subfamily comprises four members in mammals (Kir3.1- Kir3.4) that present the common topology of the inward-rectifier superfamily: two transmembrane domains flanking a highly conserved pore region with the N and C-terminus located intracellularly