ASIC2
Description
The ASIC2 (acid sensing ion channel subunit 2) is a protein-coding gene located on chromosome 17.
ASIC2, also known as ACCN1 or BNaC1, is a protein encoded by the ASIC2 gene in humans. It belongs to a family of five paralogous genes that produce proteins forming trimeric acid-sensing ion channels (ASICs) in mammals. The ASIC2 gene was first cloned in 1996 and has multiple splicing variants leading to different isoforms. These genes are predominantly expressed in the central and peripheral nervous systems. ASICs can assemble into both homotrimers (composed of three identical subunits) and heterotrimers. The ASIC2 protein shares structural features with other members of the ASIC/ENaC superfamily. It has intracellular N and C termini, two hydrophobic transmembrane (TM) regions, and a large extracellular loop rich in cysteine residues with conserved spacing. The TM regions are denoted as TM1 (closer to the N-terminus) and TM2 (closer to the C-terminus). The pore of the channel through which ions selectively flow from the extracellular side into the cytoplasm is formed by the three TM2 regions of the trimer.
ASIC2 is a cation channel with a high affinity for sodium. Its activity is triggered by extracellular protons and can be blocked by the diuretic amiloride. It also allows the passage of lithium and potassium ions. ASIC2 produces a biphasic current, characterized by a rapid inactivation phase followed by a slower sustained phase. The assembly of ASIC2 with other ASIC proteins into heteromeric channels can influence its function.
ASIC2 is also known as ACCN, ACCN1, ASIC2a, BNC1, BNaC1, MDEG, hBNaC1.
