KCNQ4

Potassium voltage-gated channel subfamily KQT member 4 also known as voltage-gated potassium channel subunit K_v7.4 is a protein that in humans is encoded by the KCNQ4 gene.

Function

The protein encoded by this gene forms a potassium channel that is thought to play a critical role in the regulation of neuronal excitability, particularly in sensory cells of the cochlea. The encoded protein can form a homomultimeric potassium channel or possibly a heteromultimeric channel in association with the protein encoded by the KCNQ3 gene.

Clinical significance

The current generated by this channel is inhibited by muscarinic acetylcholine receptor M1 and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of nonsyndromic sensorineural deafness type 2 (DFNA2), an autosomal dominant form of progressive hearing loss. Two transcript variants encoding different isoforms have been found for this gene.

Ligands

See also

KvLQT1

K_v7.1 (KvLQT1) is a potassium channel protein whose primary subunit in humans is encoded by the KCNQ1 gene. K_v7.1 is a voltage-gated potassium channel present in the cell membranes of cardiac tissue and in inner ear neurons among other tissues. In the cardiac cells, K_v7.1 mediates the I_Ks (or slow delayed rectifying K⁺) current that contributes to the repolarization of the cell, terminating the cardiac action potential and thereby the heart's contraction.

Structure

KvLQT1 is made of six membrane-spanning domains S1-S6, two intracellular domains, and a pore loop. The KvLQT1 channel is made of four KCNQ1 subunits, which form the actual ion channel.

Function

This gene encodes a protein for a voltage-gated potassium channel required for the repolarization phase of the cardiac action potential. The gene product can form heteromultimers with two other potassium channel proteins, KCNE1 and KCNE3. The gene is located in a region of chromosome 11 that contains a large number of contiguous genes that are abnormally imprinted in cancer and the Beckwith-Wiedemann syndrome. Two alternative transcripts encoding distinct isoforms have been described.

KvLQT3

K_v7.3 (KvLQT3) is a potassium channel protein coded for by the gene KCNQ3.

It is associated with benign familial neonatal epilepsy.

The M channel is a slowly activating and deactivating potassium channel that plays a critical role in the regulation of neuronal excitability. The M channel is formed by the association of the protein encoded by this gene and one of two related proteins encoded by the KCNQ2 and KCNQ5 genes, both integral membrane proteins. M channel currents are inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 2 (BFNC2), also known as epilepsy, benign neonatal type 2 (EBN2).

Interactions

KvLQT3 has been shown to interact with KCNQ5.

References

Further reading

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.