ASIC5 is a bile acid-gated sodium channel subunit belonging to the acid-sensing ion channel (ASIC) family 1. It functions as a component of ion channels that display high selectivity for sodium ions while permitting other cations 2. ASIC5 forms functional homo- or heteromeric trimers in the plasma membrane 3 and exhibits single-channel properties including ~11 pS conductance and high Na+ selectivity 4. The channel is activated synergistically by bile acids such as chenodeoxycholic acid and deoxycholic acid 4, mediating bile acid-dependent absorption and secretion in bile duct epithelial cells 2. In the central nervous system, ASIC5 may contribute to motor coordination and balance as a sodium channel in type II unipolar brush cells of the vestibulocerebellum 3. Pathologically, ASIC5 mutations have been associated with recurrent pregnancy loss; a homozygous R227I substitution (c.680G>T) impairs protein stability and prevents amiloride binding, reducing channel activation 5. Additionally, ASIC5 mutations have been identified in patients with Usher-like phenotypes presenting retinal dystrophy 6. These findings establish ASIC5's role in gastrointestinal function and suggest broader involvement in reproductive and sensory processes.