ASIC4


Acid-sensing ion channel 4 also known as amiloride-sensitive cation channel 4 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 in mammals. The cDNA of this gene was first cloned in 2000. 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 and heterotrimeric channels.

Structure and function

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