The two-pore-domain or tandem pore domain potassium channels are a family of 15 members that form what is known as leak channels which possess Goldman-Hodgkin-Katz (open) rectification. These channels are regulated by several mechanisms including signaling lipids, oxygen tension, pH, mechanical stretch, and G-proteins. Two-pore-domain potassium channels correspond structurally to a inward-rectifier potassium channel α-subunits. Each inward-rectifier potassium channel α-subunit is composed of two transmembrane α-helices, a pore helix and a potassium ion selectivity filter sequence and assembles into a tetramer forming the complete channel. The two-pore domain potassium channels instead are dimers where each subunit is essentially two α-subunits joined together. Each single channel does not have two pores; the name of the channel comes from the fact that each subunit has two P (pore) domains in its primary sequence. To quote Rang and Dale (2015), "The nomenclature is misleading, especially when they are incorrectly referred to as two-pore channels". A decrease in these leak channels activity is known as 'channel arrest', which reduces oxygen consumption and allows animals to survive anoxia. Below is a list of the 15 known two-pore-domain human potassium channels: