KvLQT3 explained

K_v7.3 (KvLQT3) is a potassium channel protein coded for by the gene KCNQ3.^[1]

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).^[1]

Interactions

KvLQT3 has been shown to interact with KCNQ5.^[2]

Further reading

• Gutman GA, Chandy KG, Grissmer S, etal . International Union of Pharmacology. LIII. Nomenclature and molecular relationships of voltage-gated potassium channels. . Pharmacol. Rev. . 57 . 4 . 473–508 . 2006 . 16382104 . 10.1124/pr.57.4.10 . 219195192 .
• Ryan SG, Wiznitzer M, Hollman C, etal . Benign familial neonatal convulsions: evidence for clinical and genetic heterogeneity. . Ann. Neurol. . 29 . 5 . 469–73 . 1991 . 1859177 . 10.1002/ana.410290504 . 25424485 .
• Lewis TB, Leach RJ, Ward K, etal . Genetic heterogeneity in benign familial neonatal convulsions: identification of a new locus on chromosome 8q. . Am. J. Hum. Genet. . 53 . 3 . 670–5 . 1993 . 8102508 . 1682419 .
• Charlier C, Singh NA, Ryan SG, etal . A pore mutation in a novel KQT-like potassium channel gene in an idiopathic epilepsy family. . Nat. Genet. . 18 . 1 . 53–5 . 1998 . 9425900 . 10.1038/ng0198-53 . 10437379 .
• Yang WP, Levesque PC, Little WA, etal . Functional expression of two KvLQT1-related potassium channels responsible for an inherited idiopathic epilepsy. . J. Biol. Chem. . 273 . 31 . 19419–23 . 1998 . 9677360 . 10.1074/jbc.273.31.19419 . free .
• Wang HS, Pan Z, Shi W, etal . KCNQ2 and KCNQ3 potassium channel subunits: molecular correlates of the M-channel. . Science . 282 . 5395 . 1890–3 . 1998 . 9836639 . 10.1126/science.282.5395.1890 . 1998Sci...282.1890W .
• Schroeder BC, Kubisch C, Stein V, Jentsch TJ . Moderate loss of function of cyclic-AMP-modulated KCNQ2/KCNQ3 K+ channels causes epilepsy. . Nature . 396 . 6712 . 687–90 . 1999 . 9872318 . 10.1038/25367 . 1998Natur.396..687S . 4417442 .
• Kubisch C, Schroeder BC, Friedrich T, etal . KCNQ4, a novel potassium channel expressed in sensory outer hair cells, is mutated in dominant deafness. . Cell . 96 . 3 . 437–46 . 1999 . 10025409 . 10.1016/S0092-8674(00)80556-5 . free .
• Selyanko AA, Hadley JK, Wood IC, etal . Two types of K(+) channel subunit, Erg1 and KCNQ2/3, contribute to the M-like current in a mammalian neuronal cell. . J. Neurosci. . 19 . 18 . 7742–56 . 1999 . 10479678 . 10.1523/JNEUROSCI.19-18-07742.1999. 6782456 .
• Shapiro MS, Roche JP, Kaftan EJ, etal . Reconstitution of muscarinic modulation of the KCNQ2/KCNQ3 K(+) channels that underlie the neuronal M current. . J. Neurosci. . 20 . 5 . 1710–21 . 2000 . 10684873 . 10.1523/JNEUROSCI.20-05-01710.2000. 6772928 . free .
• Rundfeldt C, Netzer R . The novel anticonvulsant retigabine activates M-currents in Chinese hamster ovary-cells tranfected with human KCNQ2/3 subunits. . Neurosci. Lett. . 282 . 1–2 . 73–6 . 2000 . 10713399 . 10.1016/S0304-3940(00)00866-1 . 28431577 .
• Selyanko AA, Hadley JK, Wood IC, etal . Inhibition of KCNQ1-4 potassium channels expressed in mammalian cells via M1 muscarinic acetylcholine receptors. . J. Physiol. . 522 Pt 3 . 3. 349–55 . 2000 . 10713961 . 10.1111/j.1469-7793.2000.t01-2-00349.x . 2269765 .
• Cooper EC, Aldape KD, Abosch A, etal . Colocalization and coassembly of two human brain M-type potassium channel subunits that are mutated in epilepsy. . Proc. Natl. Acad. Sci. U.S.A. . 97 . 9 . 4914–9 . 2000 . 10781098 . 10.1073/pnas.090092797 . 18332 . 2000PNAS...97.4914C . free .
• Schwake M, Pusch M, Kharkovets T, Jentsch TJ . Surface expression and single channel properties of KCNQ2/KCNQ3, M-type K+ channels involved in epilepsy. . J. Biol. Chem. . 275 . 18 . 13343–8 . 2000 . 10788442 . 10.1074/jbc.275.18.13343 . free .
• Hirose S, Zenri F, Akiyoshi H, etal . A novel mutation of KCNQ3 (c.925T-->C) in a Japanese family with benign familial neonatal convulsions. . Ann. Neurol. . 47 . 6 . 822–6 . 2000 . 10852552 . 10.1002/1531-8249(200006)47:6<822::AID-ANA19>3.0.CO;2-X . 11096248 .
• Main MJ, Cryan JE, Dupere JR, etal . Modulation of KCNQ2/3 potassium channels by the novel anticonvulsant retigabine. . Mol. Pharmacol. . 58 . 2 . 253–62 . 2000 . 10908292 . 10.1124/mol.58.2.253. 11112809 .
• Wickenden AD, Yu W, Zou A, etal . Retigabine, a novel anti-convulsant, enhances activation of KCNQ2/Q3 potassium channels. . Mol. Pharmacol. . 58 . 3 . 591–600 . 2000 . 10953053 . 10.1124/mol.58.3.591.
• Tinel N, Diochot S, Lauritzen I, etal . M-type KCNQ2-KCNQ3 potassium channels are modulated by the KCNE2 subunit. . FEBS Lett. . 480 . 2–3 . 137–41 . 2000 . 11034315 . 10.1016/S0014-5793(00)01918-9 . 8386123 . free . 2000FEBSL.480..137T .
• Wickenden AD, Zou A, Wagoner PK, Jegla T . Characterization of KCNQ5/Q3 potassium channels expressed in mammalian cells. . Br. J. Pharmacol. . 132 . 2 . 381–4 . 2001 . 11159685 . 10.1038/sj.bjp.0703861 . 1572592 .
• Yus-Najera E, Santana-Castro I, Villarroel A . The identification and characterization of a noncontinuous calmodulin-binding site in noninactivating voltage-dependent KCNQ potassium channels. . J. Biol. Chem. . 277 . 32 . 28545–53 . 2002 . 12032157 . 10.1074/jbc.M204130200 . free .

Notes and References

1. Web site: Entrez Gene: KCNQ3 potassium voltage-gated channel, KQT-like subfamily, member 3.
2. 10.1016/S0306-4522(03)00321-X . Yus-Nájera . E . Muñoz A . Salvador N . Jensen B S . Rasmussen H B . Defelipe J . Villarroel A . 2003. Localization of KCNQ5 in the normal and epileptic human temporal neocortex and hippocampal formation . Neuroscience . 120 . 2 . 353–64 . 0306-4522. 12890507 . 38381189 .