Potassium channels

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Potassium channels are fundamental regulators of excitability. They control the frequency and the shape of action potential waveform, the secretion of hormones and neurotransmitters and cell membrane potential. Their activity may be regulated by voltage, calcium and neurotransmitters (and the signalling pathways they stimulate). They consist of a primary pore-forming a subunit often associated with auxiliary regulatory subunits. Since there are over 70 different genes encoding K channels α subunits in the human genome, it is beyond the scope of this guide to treat each subunit individually. Instead, channels have been grouped into families and subfamilies based on their structural and functional properties. The three main families are the 2TM (two transmembrane domain), 4TM and 6TM families. A standardised nomenclature for potassium channels has been proposed by the NC-IUPHAR subcommittees on potassium channels [1-4].


Inwardly rectifying potassium channels


More information on this family may be found on the IUPHAR-DB family and introduction pages.


Overview « Hide

The 2TM domain family of K channels are also known as the inward-rectifier K channel family. This family includes the strong inward-rectifier K channels (KIR2.x), the G-protein-activated inward-rectifier K channels (KIR3.x) and the ATP-sensitive K channels (KIR6.x, which combine with sulphonylurea receptors (SUR)). The pore-forming a subunits form tetramers, and heteromeric channels may be formed within subfamilies (e.g. KIR3.2 with KIR3.3).


Unless otherwise stated all data refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Subunits

Kir1.1 Show »

Kir2.1 Show »

Kir2.2 Show »

Kir2.3 Show »

Kir2.4 Show »

Kir3.1 Show »

Kir3.2 Show »

Kir3.3 Show »

Kir3.4 Show »

Kir4.1 Show »

Kir4.2 Show »

Kir5.1 Show »

Kir6.1 Show »

Kir6.2 Show »

Kir7.1 Show »


Two-P potassium channels


More information on this family may be found on the IUPHAR-DB family and introduction pages.


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The 4TM family of K channels are thought to underlie many leak currents in native cells. They are open at all voltages and regulated by a wide array of neurotransmitters and biochemical mediators. The primary pore-forming αsubunit contains two pore domains (indeed, they are often referred to as two-pore domain K channels or K2P) and so it is envisaged that they form functional dimers rather than the usual K channel tetramers. There is some evidence that they can form heterodimers within subfamilies (e.g. K2P3.1 with K2P9.1). There is no current, clear, consensus on nomenclature of 4TM K channels, nor on the division into subfamilies [1]. The suggested division into subfamilies, below, is based on similarities in both structural and functional properties within subfamilies.


Unless otherwise stated all data refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Subunits

K2P1.1 Show »

K2P2.1 Show »

K2P3.1 Show »

K2P4.1 Show »

K2P5.1 Show »

K2P6.1 Show »

K2P7.1 Show »

K2P9.1 Show »

K2P10.1 Show »

K2P12.1 Show »

K2P13.1 Show »

K2P15.1 Show »

K2P16.1 Show »

K2P17.1 Show »

K2P18.1 Show »


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Voltage-gated potassium channels


More information on this family may be found on the IUPHAR-DB family and introduction pages.


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The 6TM family of K channels comprises the voltage-gated KV subfamilies, the KCNQ subfamily the EAG subfamily (which includes herg channels), the Ca2+-activated Slo subfamily (actually with 7TM) and the Ca2+-activated SK subfamily. As for the 2TM family, the pore-forming a subunits form tetramers and heteromeric channels may be formed within subfamilies (e.g. KV1.1 with KV1.2; KCNQ2 with KCNQ3).


Unless otherwise stated all data refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Subunits

Kv1.1 Show »

Kv1.2 Show »

Kv1.3 Show »

Kv1.4 Show »

Kv1.5 Show »

Kv1.6 Show »

Kv1.7 Show »

Kv1.8 Show »

Kv2.1 Show »

Kv2.2 Show »

Kv3.1 Show »

Kv3.2 Show »

Kv3.3 Show »

Kv3.4 Show »

Kv4.1 Show »

Kv4.2 Show »

Kv4.3 Show »

Kv5.1 Show »

Kv6.1 Show »

Kv6.2 Show »

Kv6.3 Show »

Kv6.4 Show »

Kv7.1 Show »

Kv7.2 Show »

Kv7.3 Show »

Kv7.4 Show »

Kv7.5 Show »

Kv8.1 Show »

Kv8.2 Show »

Kv9.1 Show »

Kv9.2 Show »

Kv9.3 Show »

Kv10.1 Show »

Kv10.2 Show »

Kv11.1 Show »

Kv11.2 Show »

Kv11.3 Show »

Kv12.1 Show »

Kv12.2 Show »

Kv12.3 Show »


Calcium-activated potassium channels


More information on this family may be found on the IUPHAR-DB family and introduction pages.


Overview « Hide

The 6TM family of K channels comprises the voltage-gated KV subfamilies, the KCNQ subfamily the EAG subfamily (which includes herg channels), the Ca2+-activated Slo subfamily (actually with 7TM) and the Ca2+-activated SK subfamily. As for the 2TM family, the pore-forming a subunits form tetramers and heteromeric channels may be formed within subfamilies (e.g. KV1.1 with KV1.2; KCNQ2 with KCNQ3).


Unless otherwise stated all data refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Subunits

KCa1.1 Show »

KCa2.1 Show »

KCa2.2 Show »

KCa2.3 Show »

KCa3.1 Show »

KCa4.1 Show »

KCa4.2 Show »

KCa5.1 Show »


Further Reading Show »

References Show »