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
Inward-rectifier potassium channels (Kir, IRK) are a specific Lipid-gated_ion_channels, lipid-gated subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are acti ...
α-subunits. Each inward-rectifier potassium channel α-subunit is composed of two
transmembrane
A transmembrane protein is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently u ...
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:
See also
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Ion channel
Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by Gating (electrophysiol ...
*
Potassium channel
References
External links
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Ion channels