Two-pore-domain potassium channels: This family of 15 members form what is known as "leak channels" which possess Goldman-Hodgkin-Katz (open) rectification. These channels are regulated by several mechanisms including oxygen tension, pH, mechanical stretch, and G-proteins.  Their name is derived from the fact that the α subunits consist of four transmembrane segments, each containing two<unk>  loops.  As such, they structurally correspond to two inward-rectifier α subunits and thus form dimers in the membrane.
Below is a list of the 15 known two-pore-domain human potassium channels:
Tandem pore domain potassium channel
Light-gated ion channel
Cyclic nucleotide-gated ion channel
Chloride channel
Magnesium transporters
Inward-rectifier potassium ion channel
Sodium calcium exchanger
Voltage-dependent calcium channel