ASIC5
ASIC5 gene is one of the five paralogous genes that encode proteins that form trimeric Acid-sensing ion channels (ASICs) in mammals.[1] Aliases previously used for this gene include ACCN5 and BASIC. The protein encoded by this gene does not appear to be acid responsive. The cDNA coding for this protein was first characterized in 2000.[2] 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.[3]
Structure and Function
This gene encodes a member of the ASIC/ENaC superfamily of proteins.[4] 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
- ^ a b Hanukoglu I (2017). "ASIC and ENaC type sodium channels: Conformational states and the structures of the ion selectivity filters". FEBS Journal. 284 (4): 525–545. doi:10.1111/febs.13840. PMID 27580245.
- ^ Schaefer, L; Sakai, H; Mattei, M; Lazdunski, M; Lingueglia, E (14 April 2000). "Molecular cloning, functional expression and chromosomal localization of an amiloride-sensitive Na(+) channel from human small intestine". FEBS Letters. 471 (2–3): 205–10. doi:10.1016/s0014-5793(00)01403-4. PMID 10767424.
- ^ Babinski K, Catarsi S, Biagini G, Séguéla P (Sep 2000). "Mammalian ASIC2a and ASIC3 subunits co-assemble into heteromeric proton-gated channels sensitive to Gd3+". The Journal of Biological Chemistry. 275 (37): 28519–25. doi:10.1074/jbc.M004114200. PMID 10842183.
- ^ Hanukoglu I, Hanukoglu A (Jan 2016). "Epithelial sodium channel (ENaC) family: Phylogeny, structure-function, tissue distribution, and associated inherited diseases". Gene. 579 (2): 95–132. doi:10.1016/j.gene.2015.12.061. PMC 4756657. PMID 26772908.
Further reading