Potassium channels

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

Overview

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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 [4-5,12,17].

Calcium-activated potassium channels

Overview

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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).

Subunits

KCa1.1 Show summary » More detailed page

KCa2.1 Show summary » More detailed page

KCa2.2 Show summary » More detailed page

KCa2.3 Show summary » More detailed page

KCa3.1 Show summary » More detailed page

KCa4.1 Show summary » More detailed page

KCa4.2 Show summary » More detailed page

KCa5.1 Show summary » More detailed page

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Inwardly rectifying potassium channels

Overview

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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).

Subunits

Kir1.1 Show summary » More detailed page

Kir2.1 Show summary » More detailed page

Kir2.2 Show summary » More detailed page

Kir2.3 Show summary » More detailed page

Kir2.4 Show summary » More detailed page

Kir3.1 Show summary » More detailed page

Kir3.2 Show summary » More detailed page

Kir3.3 Show summary » More detailed page

Kir3.4 Show summary » More detailed page

Kir4.1 Show summary » More detailed page

Kir4.2 Show summary » More detailed page

Kir5.1 Show summary » More detailed page

Kir6.1 Show summary » More detailed page

Kir6.2 Show summary » More detailed page

Kir7.1 Show summary » More detailed page

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Two-P potassium channels

Overview

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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 [4]. The suggested division into subfamilies, below, is based on similarities in both structural and functional properties within subfamilies.

Subunits

K2P1.1 Show summary » More detailed page

K2P2.1 Show summary » More detailed page

K2P3.1 Show summary » More detailed page

K2P4.1 Show summary » More detailed page

K2P5.1 Show summary » More detailed page

K2P6.1 Show summary » More detailed page

K2P7.1 Show summary » More detailed page

K2P9.1 Show summary » More detailed page

K2P10.1 Show summary » More detailed page

K2P12.1 Show summary » More detailed page

K2P13.1 Show summary » More detailed page

K2P15.1 Show summary » More detailed page

K2P16.1 Show summary » More detailed page

K2P17.1 Show summary » More detailed page

K2P18.1 Show summary » More detailed page

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Voltage-gated potassium channels

Overview

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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).

Subunits

Kv1.1 Show summary » More detailed page

Kv1.2 Show summary » More detailed page

Kv1.3 Show summary » More detailed page

Kv1.4 Show summary » More detailed page

Kv1.5 Show summary » More detailed page

Kv1.6 Show summary » More detailed page

Kv1.7 Show summary » More detailed page

Kv1.8 Show summary » More detailed page

Kv2.1 Show summary » More detailed page

Kv2.2 Show summary » More detailed page

Kv3.1 Show summary » More detailed page

Kv3.2 Show summary » More detailed page

Kv3.3 Show summary » More detailed page

Kv3.4 Show summary » More detailed page

Kv4.1 Show summary » More detailed page

Kv4.2 Show summary » More detailed page

Kv4.3 Show summary » More detailed page

Kv5.1 Show summary » More detailed page

Kv6.1 Show summary » More detailed page

Kv6.2 Show summary » More detailed page

Kv6.3 Show summary » More detailed page

Kv6.4 Show summary » More detailed page

Kv7.1 Show summary » More detailed page

Kv7.2 Show summary » More detailed page

Kv7.3 Show summary » More detailed page

Kv7.4 Show summary » More detailed page

Kv7.5 Show summary » More detailed page

Kv8.1 Show summary » More detailed page

Kv8.2 Show summary » More detailed page

Kv9.1 Show summary » More detailed page

Kv9.2 Show summary » More detailed page

Kv9.3 Show summary » More detailed page

Kv10.1 Show summary » More detailed page

Kv10.2 Show summary » More detailed page

Kv11.1 Show summary » More detailed page

Kv11.2 Show summary » More detailed page

Kv11.3 Show summary » More detailed page

Kv12.1 Show summary » More detailed page

Kv12.2 Show summary » More detailed page

Kv12.3 Show summary » More detailed page

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References

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