Biology:ASIC2

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Acid-sensing ion channel 2 (ASIC2) also known as amiloride-sensitive cation channel 1, neuronal (ACCN1) or brain sodium channel 1 (BNaC1) is a protein that in humans is encoded by the ASIC2 gene. The ASIC2 gene is one of the five paralogous genes that encode proteins that form trimeric acid-sensing ion channels (ASICs) in mammals.[1] The cDNA of this gene was first cloned in 1996.[2][3][4][5] The ASIC genes have splicing variants that encode different proteins that are called isoforms.

These genes are mainly expressed in the central and peripheral nervous system.

ASICs can form both homotrimeric (meaning composed of three identical subunits) and heterotrimeric channels.[6][7]

Structure and function

This gene encodes a member of the ASIC/ENaC superfamily of proteins.[8] The members of this family are amiloride-sensitive sodium channels that contain intracellular N and C termini, 2 hydrophobic transmembrane (TM) regions, and a large extracellular loop, which has many cysteine residues with conserved spacing. The TM regions are generally symbolized as TM1 (clone to N-terminus) and TM2 (close to C-terminus).

The pore of the channel through which ions selectively flow from the extracellular side into the cytoplasm is formed by the three TM2 regions of the trimer.[1]

References

  1. 1.0 1.1 "ASIC and ENaC type sodium channels: Conformational states and the structures of the ion selectivity filters". FEBS Journal 284 (4): 525–545. 2017. doi:10.1111/febs.13840. PMID 27580245. https://zenodo.org/record/890906. 
  2. "The human degenerin MDEG, an amiloride-sensitive neuronal cation channel, is localized on chromosome 17q11.2-17q12 close to the microsatellite D17S798". Genomics 37 (2): 269–70. Oct 1996. doi:10.1006/geno.1996.0558. PMID 8921408. 
  3. "Cloning and expression of a novel human brain Na+ channel". The Journal of Biological Chemistry 271 (14): 7879–82. Apr 1996. doi:10.1074/jbc.271.14.7879. PMID 8626462. 
  4. "The mammalian degenerin MDEG, an amiloride-sensitive cation channel activated by mutations causing neurodegeneration in Caenorhabditis elegans". The Journal of Biological Chemistry 271 (18): 10433–6. May 1996. doi:10.1074/jbc.271.18.10433. PMID 8631835. 
  5. "BNaC1 and BNaC2 constitute a new family of human neuronal sodium channels related to degenerins and epithelial sodium channels". Proceedings of the National Academy of Sciences of the United States of America 94 (4): 1459–64. Feb 1997. doi:10.1073/pnas.94.4.1459. PMID 9037075. Bibcode1997PNAS...94.1459G. 
  6. "Mammalian ASIC2a and ASIC3 subunits co-assemble into heteromeric proton-gated channels sensitive to Gd3+". The Journal of Biological Chemistry 275 (37): 28519–25. Sep 2000. doi:10.1074/jbc.M004114200. PMID 10842183. 
  7. "The acid-sensitive ionic channel subunit ASIC and the mammalian degenerin MDEG form a heteromultimeric H+-gated Na+ channel with novel properties". The Journal of Biological Chemistry 272 (46): 28819–22. Nov 1997. doi:10.1074/jbc.272.46.28819. PMID 9360943. 
  8. "Epithelial sodium channel (ENaC) family: Phylogeny, structure-function, tissue distribution, and associated inherited diseases.". Gene 579 (2): 95–132. Jan 2016. doi:10.1016/j.gene.2015.12.061. PMID 26772908. 

Further reading

External links