Acid-sensing ion channel 2 (ASIC2)

Acid-sensing ion channel 2 (ASIC2) is a voltage-insensitive, proton-gated sodium ion channel widely expressed in the mammalian nervous system and some non-neural tissues. ASIC2 is a member of the DEG/ENaC (epithelial sodium channel/degenerin) superfamily, typically functioning as a part of trimeric channels—either as homotrimers or heterotrimers with other ASIC subunits. Channels containing ASIC2 subunits are activated by extracellular acidification, leading to sodium influx and neuronal depolarization, and are involved in mechanosensation, pain perception, and regulation of neuronal excitability. Splice variants ASIC2a and ASIC2b differ in function: ASIC2a forms functional channels alone (low proton sensitivity, slow desensitization) and is essential for baroreceptor and synaptic function, while ASIC2b modulates channel activity when heteromerized. ASIC2 is implicated in diseases such as neurodegeneration, ischemic injury, cardiovascular dysregulation, arthritis, and cancer, representing both a therapeutic target and a disease biomarker. Pharmacologically, ASM channels (including ASIC2) are inhibited by amiloride and other small molecules, but therapeutic targeting requires caution to avoid interfering with normal physiological roles.

Other names

ACCNACCN1Amiloride-sensitive cation channel 1, neuronalBrain sodium channel 1BNaC1BNC1MDEGASIC2ahBNaC1Mammalian degenerin homologdegenerin

Blockade of proton-gated sodium influx (e.g., by amiloride, reduces membrane depolarization) Modulation of channel trafficking or surface expression (some drugs or proteins modulate ASIC2 presence at the membrane)