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.[1] These channels are regulated by several mechanisms including signaling lipids, oxygen tension, pH, mechanical stretch, and G-proteins.[2] 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.[3] The two-pore domain potassium channels instead are dimers where each subunit is essentially two α-subunits joined together.[4]
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.[5] To quote Rang and Dale (2015), "The nomenclature is misleading, especially when they are incorrectly referred to as two-pore channels".[6]
Below is a list of the 15 known two-pore-domain human potassium channels:[1]
Gene | Channel[7] | Family | Aliases |
KCNK1 | K2p1.1 | TWIK[2][8] | TWIK-1 |
KCNK2 | K2p2.1 | TREK[2][8] | TREK-1 |
KCNK3 | K2p3.1 | TASK[2][8] | TASK-1 |
KCNK4 | K2p4.1 | TREK[2][8] | TRAAK[9] |
KCNK5 | K2p5.1 | TASK[2][8] | TASK-2[10] |
KCNK6 | K2p6.1 | TWIK[2][8] | TWIK-2 |
KCNK7 | K2p7.1 | TWIK[2][8] | |
KCNK9 | K2p9.1 | TASK[2][8] | TASK-3 |
KCNK10 | K2p10.1 | TREK[2][8] | TREK-2 |
KCNK12 | K2p12.1 | THIK | THIK-2 |
KCNK13 | K2p13.1 | THIK | THIK-1 |
KCNK15 | K2p15.1 | TASK[2][8] | TASK-5 |
KCNK16 | K2p16.1 | TALK[2][8] | TALK-1 |
KCNK17 | K2p17.1 | TALK[2][8] | TALK-2, TASK-4 |
KCNK18 | K2p18.1 | TRIK, TRESK[2][8][11][12] |
|
|
|