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(+). Activation by an extracellular pH drop is followed by a rapid pH-independent inactivation. Heteromeric channel assembly seems to modulate channel properties. Homotrimer or heterotrimer with other ASIC proteins (By similarity). Interacts with PRKCABP (By similarity). Interacts with STOM; this regulates channel activity. Interacts with ASIC1. Isoform 2 interacts with ASIC3. Heterotrimer of Asic1a-Asic2a interacts with the snake venom mambalgin-1, mambalgin-2 and mambalgin-3 (PubMed:23034652, PubMed:23624383). Heterotrimer of Asic1a-Asic2b interacts with the snake venom mambalgin-1 and mambalgin-2 (PubMed:23034652). Localized at the plasma membrane of neurons, in the soma and punctated peripheral processes. Expressed in sciatic nerve and dorsal root ganglion (DRG) (at protein level). Both isoforms display the same expression pattern except in DRG where isoform 2 is more abundantly expressed. Widely distributed throughout the brain. Highly expressed in the main olfactory bulb, neo- and allo-cortical regions, hippocampal formation, habenula, basolateral amygdaloid nuclei, and cerebellum. In the olfactory system, expressed in the glomerular cell layer, the internal granular layer, and the mitral and internal plexiform cell layers. Within the glomerular layer, restricted to the periglomerular cells. In the neocortex, strongly expressed in the large pyramidal neurons in all cortical layers as well as in the oligo-, astro-, or micro-glia cells. In the hippocampal formation, expressed in dentate granule cells and hilar neurons, as well as in pyramidal cells of CA1-CA3 subfields. Expressed in stratum oriens and radiatum of all subfields. Within the thalamus, expressed moderately in the medial and lateral habenula. In the cerebellar cortex expressed in Purkinje cells and granule cells. Expressed at low levels in choroid plexus. Appears just before birth, reaches maximum levels after birth, then declines slightly until adulthood. Up-regulation upon tissues inflammation is abolished by anti-inflammatory drugs. Regulated by Zn(2+). Inhibited by anti-inflammatory drugs like salicylic acid. Seems to be inactive as monomer or in a monomeric assembly and is not activated by mutagenesis of Gly-430. Mutagenesis of Ser-60 into Gly reduces activation by PKC through PRKCABP/PICK-1 of a ASIC3/ACCN3-ASIC2/ASIC2b channel. Belongs to the amiloride-sensitive sodium channel (TC 1.A.6) family. ASIC2 subfamily.