Acid-sensing ion channel 4 (ASIC4) also known as amiloride-sensitive cation channel 4 (ACCN4) is a
protein that in humans is encoded by the ASIC4
gene. The ASIC4 gene is one of the five
paralogous genes that encode proteins that form trimeric
acid-sensing ion channels (ASICs) in mammals.[5] The cDNA of this gene was first cloned in 2000.[6][7] 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.[8]
Structure and function
This gene encodes a member of the ASIC/
ENaC superfamily of proteins.[9] The members of this family are
amiloride-sensitive
sodium channels that contain
intracellular N and C termini, 2
hydrophobictransmembrane (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. [5]
Donier E, Rugiero F, Jacob C, Wood JN (2008). "Regulation of ASIC activity by ASIC4--new insights into ASIC channel function revealed by a yeast two-hybrid assay". Eur. J. Neurosci. 28 (1): 74–86.
doi:
10.1111/j.1460-9568.2008.06282.x.
PMID18662336.
S2CID29369987.