ASIC1 is a member of a family of Na+ channels that are activated by external protons. The family includes another three members ASIC2, ASIC3 and ASIC4. The ASICs are in fact part of a larger superfamily termed epithelial Na+ channels (EnaC) and share with it the same basic characteristics: two transmembrane spanning domains, a large extracellular domain and short intracellular N and C termini. nThere are two recognized splice variants of the ASIC1 gene that differ on their N-termini, ASIC1a and ASIC1b that have different tissue distributions and functions. nThe ASIC1 responds to a decrease in extracellular pH with an inward cation current that is quickly inactivated despite the continuous presence of protons in the medium. nLately, ASIC1 has been implicated in processes such as learning and memory in the central nervous system.
