Biology:KCNA4

From HandWiki
Short description: Protein-coding gene in the species Homo sapiens


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example
Potassium channel Kv1.4 tandem inactivation domain
PDB 1kn7 EBI.jpg
solution structure of the tandem inactivation domain (residues 1-75) of potassium channel rck4 (kv1.4)
Identifiers
SymbolK_channel_TID
PfamPF07941
InterProIPR012897
SCOP21kn7 / SCOPe / SUPFAM

Potassium voltage-gated channel subfamily A member 4 also known as Kv1.4 is a protein that in humans is encoded by the KCNA4 gene.[1][2][3] It contributes to the cardiac transient outward potassium current (Ito1), the main contributing current to the repolarizing phase 1 of the cardiac action potential.[4]

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.[3]

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.[5]

Interactions

KCNA4 has been shown to interact with DLG4,[6][7][8][9] KCNA2[10] and DLG1.[6][8][11]

See also

References

  1. ↑ "Sequence of a human fetal skeletal muscle potassium channel cDNA related to RCK4". Nucleic Acids Research 18 (23): 7160. December 1990. doi:10.1093/nar/18.23.7160. PMID 2263489. 
  2. ↑ "International Union of Pharmacology. LIII. Nomenclature and molecular relationships of voltage-gated potassium channels". Pharmacological Reviews 57 (4): 473–508. December 2005. doi:10.1124/pr.57.4.10. PMID 16382104. 
  3. ↑ 3.0 3.1 "Entrez Gene: KCNA4 potassium voltage-gated channel, shaker-related subfamily, member 4". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=3739. 
  4. ↑ "The molecular physiology of the cardiac transient outward potassium current (I(to)) in normal and diseased myocardium". Journal of Molecular and Cellular Cardiology 33 (5): 851–72. May 2001. doi:10.1006/jmcc.2001.1376. PMID 11343410. 
  5. ↑ "Solution structure and function of the "tandem inactivation domain" of the neuronal A-type potassium channel Kv1.4". The Journal of Biological Chemistry 278 (18): 16142–50. May 2003. doi:10.1074/jbc.M210191200. PMID 12590144. 
  6. ↑ 6.0 6.1 "Inward rectifier K+ channel Kir2.3 is localized at the postsynaptic membrane of excitatory synapses". American Journal of Physiology. Cell Physiology 282 (6): C1396-403. June 2002. doi:10.1152/ajpcell.00615.2001. PMID 11997254. 
  7. ↑ "CRIPT, a novel postsynaptic protein that binds to the third PDZ domain of PSD-95/SAP90". Neuron 20 (4): 693–707. April 1998. doi:10.1016/S0896-6273(00)81009-0. PMID 9581762. 
  8. ↑ 8.0 8.1 "Differential K+ channel clustering activity of PSD-95 and SAP97, two related membrane-associated putative guanylate kinases". Neuropharmacology 35 (7): 993–1000. 1996. doi:10.1016/0028-3908(96)00093-7. PMID 8938729. 
  9. ↑ "N-terminal PDZ-binding domain in Kv1 potassium channels". FEBS Letters 531 (3): 529–37. November 2002. doi:10.1016/S0014-5793(02)03572-X. PMID 12435606. 
  10. ↑ "Subunit composition of Kv1 channels in human CNS". Journal of Neurochemistry 73 (2): 849–58. August 1999. doi:10.1046/j.1471-4159.1999.0730849.x. PMID 10428084. 
  11. ↑ "SAP97 increases Kv1.5 currents through an indirect N-terminal mechanism". FEBS Letters 547 (1–3): 205–11. July 2003. doi:10.1016/S0014-5793(03)00668-9. PMID 12860415. 

Further reading

External links

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



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