KCNA4

VALUE_ERROR (nil)
Identifiers
Aliases
External IDs	GeneCards: [1]
Orthologs
Species	Human	Mouse
Entrez	n/a	n/a
Ensembl	n/a	n/a
UniProt	n/a	n/a
RefSeq (mRNA)	n/a	n/a
RefSeq (protein)	n/a	n/a
Location (UCSC)	n/a	n/a
PubMed search	n/a	n/a
Wikidata
View/Edit Human

Potassium channel Kv1.4 tandem inactivation domain
File:PDB 1kn7 EBI.jpg solution structure of the tandem inactivation domain (residues 1-75) of potassium channel rck4 (kv1.4)
Identifiers
Symbol	K_channel_TID
Pfam	PF07941
InterPro	IPR012897
SCOP	1kn7
SUPERFAMILY	1kn7
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Potassium voltage-gated channel subfamily A member 4 also known as K_v1.4 is a protein that in humans is encoded by the KCNA4 gene. It contributes to the cardiac transient outward potassium current (I_to1), the main contributing current to the repolarizing phase 1 of the cardiac action potential.

Description

Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the A-type potassium current class, the members of which may be important in the regulation of the fast repolarizing phase of action potentials in heart and thus may influence the duration of cardiac action potential. The coding region of this gene is intronless, and the gene is clustered with genes KCNA3 and KCNA10 on chromosome 1 in humans.

KCNA4 (Kv1.4) contains a tandem inactivation domain at the N terminus. It is composed of two subdomains. Inactivation domain 1 (ID1, residues 1-38) consists of a flexible N terminus anchored at a 5-turn helix, and is thought to work by occluding the ion pathway, as is the case with a classical ball domain. Inactivation domain 2 (ID2, residues 40-50) is a 2.5 turn helix with a high proportion of hydrophobic residues that probably serves to attach ID1 to the cytoplasmic face of the channel. In this way, it can promote rapid access of ID1 to the receptor site in the open channel. ID1 and ID2 function together to bring about fast inactivation of the Kv1.4 channel, which is important for the role of the channel in short-term plasticity.

Interactions

KCNA4 has been shown to interact with DLG4, KCNA2 and DLG1.

See also

• Voltage-gated potassium channel
• Voltage-gated potassium-channel Kv1.4 IRES

Further reading

• Scott HS, Litjens T, Hopwood JJ, Morris CP (1993). "PCR detection of two RFLPs in exon I of the alpha-L-iduronidase (IDUA) gene". Hum. Genet. 90 (3): 327. doi:10.1007/bf00220095. PMID 1362562.
• Gessler M, Grupe A, Grzeschik KH, Pongs O (1993). "The potassium channel gene HK1 maps to human chromosome 11p14.1, close to the FSHB gene". Hum. Genet. 90 (3): 319–21. doi:10.1007/bf00220091. PMID 1487251.
• Philipson LH, Hice RE, Schaefer K, et al. (1991). "Sequence and functional expression in Xenopus oocytes of a human insulinoma and islet potassium channel". Proc. Natl. Acad. Sci. U.S.A. 88 (1): 53–7. Bibcode:1991PNAS...88...53P. doi:10.1073/pnas.88.1.53. PMC 50746. PMID 1986382.
• Tamkun MM, Knoth KM, Walbridge JA, et al. (1991). "Molecular cloning and characterization of two voltage-gated K+ channel cDNAs from human ventricle". FASEB J. 5 (3): 331–7. PMID 2001794.
• Kim E, Niethammer M, Rothschild A, et al. (1995). "Clustering of Shaker-type K+ channels by interaction with a family of membrane-associated guanylate kinases". Nature. 378 (6552): 85–8. Bibcode:1995Natur.378...85K. doi:10.1038/378085a0. PMID 7477295.
• Klocke R, Roberds SL, Tamkun MM, et al. (1994). "Chromosomal mapping in the mouse of eight K(+)-channel genes representing the four Shaker-like subfamilies Shaker, Shab, Shaw, and Shal". Genomics. 18 (3): 568–74. doi:10.1016/S0888-7543(05)80358-1. PMID 7905852.
• Philipson LH, Eddy RL, Shows TB, Bell GI (1993). "Assignment of human potassium channel gene KCNA4 (Kv1.4, PCN2) to chromosome 11q13.4→q14.1". Genomics. 15 (2): 463–4. doi:10.1006/geno.1993.1094. PMID 8449523.
• Niethammer M, Kim E, Sheng M (1996). "Interaction between the C terminus of NMDA receptor subunits and multiple members of the PSD-95 family of membrane-associated guanylate kinases". J. Neurosci. 16 (7): 2157–63. PMID 8601796.
• Kim E, Sheng M (1997). "Differential K+ channel clustering activity of PSD-95 and SAP97, two related membrane-associated putative guanylate kinases". Neuropharmacology. 35 (7): 993–1000. doi:10.1016/0028-3908(96)00093-7. PMID 8938729.
• Kim E, Naisbitt S, Hsueh YP, et al. (1997). "GKAP, a novel synaptic protein that interacts with the guanylate kinase-like domain of the PSD-95/SAP90 family of channel clustering molecules". J. Cell Biol. 136 (3): 669–78. doi:10.1083/jcb.136.3.669. PMC 2134290. PMID 9024696.
• Niethammer M, Valtschanoff JG, Kapoor TM, et al. (1998). "CRIPT, a novel postsynaptic protein that binds to the third PDZ domain of PSD-95/SAP90". Neuron. 20 (4): 693–707. doi:10.1016/S0896-6273(00)81009-0. PMID 9581762.
• Brenman JE, Topinka JR, Cooper EC, et al. (1998). "Localization of postsynaptic density-93 to dendritic microtubules and interaction with microtubule-associated protein 1A". J. Neurosci. 18 (21): 8805–13. PMID 9786987.
• Coleman SK, Newcombe J, Pryke J, Dolly JO (1999). "Subunit composition of Kv1 channels in human CNS". J. Neurochem. 73 (2): 849–58. doi:10.1046/j.1471-4159.1999.0730849.x. PMID 10428084.
• D'Adamo MC, Imbrici P, Sponcichetti F, Pessia M (1999). "Mutations in the KCNA1 gene associated with episodic ataxia type-1 syndrome impair heteromeric voltage-gated K(+) channel function". FASEB J. 13 (11): 1335–45. PMID 10428758.
• Hogan A, Shepherd L, Chabot J, et al. (2001). "Interaction of gamma 1-syntrophin with diacylglycerol kinase-zeta. Regulation of nuclear localization by PDZ interactions". J. Biol. Chem. 276 (28): 26526–33. doi:10.1074/jbc.M104156200. PMID 11352924.
• Cukovic D, Lu GW, Wible B, et al. (2001). "A discrete amino terminal domain of Kv1.5 and Kv1.4 potassium channels interacts with the spectrin repeats of alpha-actinin-2". FEBS Lett. 498 (1): 87–92. doi:10.1016/S0014-5793(01)02505-4. PMID 11389904.
• Imamura F, Maeda S, Doi T, Fujiyoshi Y (2002). "Ligand binding of the second PDZ domain regulates clustering of PSD-95 with the Kv1.4 potassium channel". J. Biol. Chem. 277 (5): 3640–6. doi:10.1074/jbc.M106940200. PMID 11723117.
• Piserchio A, Pellegrini M, Mehta S, et al. (2002). "The PDZ1 domain of SAP90. Characterization of structure and binding". J. Biol. Chem. 277 (9): 6967–73. doi:10.1074/jbc.M109453200. PMID 11744724.

External links

• Kv1.4+Potassium+Channel at the US National Library of Medicine Medical Subject Headings (MeSH)
• KCNA4+protein,+human at the US National Library of Medicine Medical Subject Headings (MeSH)

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

This article incorporates text from the public domain Pfam and InterPro: IPR012897