Cation channel with high affinity for sodium, which is gated by extracellular protons and inhibited by the diuretic amiloride. Also permeable for Li(+) and K(+). Generates a biphasic current with a fast inactivating and a slow sustained phase. Heteromeric channel assembly seems to modulate. Homotrimer or heterotrimer with other ASIC proteins (By similarity). Interacts with STOM; this regulates channel activity (By similarity). Interacts with PRKCABP and ASIC3. Heterotrimer of Asic1a-Asic2a interacts with the snake venom mambalgin-1 (PubMed:23034652). Heterotrimer of Asic1a-Asic2a interacts with the snake venom mambalgin-2 and mambalgin-3 (By similarity). Heterotrimer of Asic1a-Asic2b interacts with the snake venom mambalgin-1 and mambalgin-2 (By similarity). Localized at the plasma membrane of neurons, in the soma and punctated peripheral processes. Brain and spinal cord. Isoform 1 is also detected in testis, liver, colon and ovary. Inhibited by anti-inflammatory drugs like salicylic acid (By similarity). Regulated by Zn(2+). Belongs to the amiloride-sensitive sodium channel (TC 1.A.6) family. ASIC2 subfamily.