ASIC3 is a member of a family of Na+ channels that are activated by external protons. The family includes another three members ASIC1, ASIC2 and ASIC4. The ASICs are in fact part of a larger superfamily termed degenerin/epithelial Na+ channels (DEG/ENaC) and share with it the same basic characteristics: two transmembrane spanning domains, a large extracellular domain and short intracellular N and C termini.nThe functional channel is composed of 4 subunits that can be assembled as homo or heterotetramers with the other ASIC subunits
