extracellular domain of neuronal acetylcholine receptor subunit alpha 9 (CHRNA9)
This subfamily contains the extracellular domain of nicotinic acetylcholine receptor subunit alpha 9 (alpha9), encoded by the CHRNA9 gene. This protein is involved in cochlea hair cell development and is also expressed in the outer hair cells (OHCs) of the adult cochlea as well as in keratinocytes, the pituitary gland, B-cells, and T-cells. Mammalian alpha9 subunits can form functional homomeric alpha9 receptors as well as the heteromeric alpha9alpha10 receptors, the latter being atypical since the heteromeric alpha9alpha10 receptor is composed only of alpha subunits compared to nAChRs typically assembled from alpha and beta subunits. A stoichiometry of (alpha9)2(alpha10)3 has been determined for the rat recombinant receptor. The alpha9alpha10 nAChR is an important therapeutic target for pain; selective block of alpha9alpha10 nicotinic acetylcholine receptors by the conotoxin RgIA has been shown to be analgesic in an animal model of nerve injury pain, and accelerates recovery of nerve function after injury, possibly through immune/inflammatory-mediated mechanisms. CHRNA9 polymorphisms are associated with non-small cell lung cancer, and effect of a particular SNP (rs73229797) and passive smoking exposure on risk of breast malignancy has been observed.
Comment:this structure superimposes very well with the structure of the corresponding domains of homologous proteins in pentameric states, denoting native folding
Structure:4UY2: Homo sapiens neuronal acetylcholine receptor subunit alpha-9 dimer interface; contacts at 4.0A - View structure with Cn3D
Jiyao W et al.(2023). "The conserved domain database in 2023.",