Neuronal nicotinic acetylcholine receptor β‐subunit is coded for by the cDNA clone α4

摘要

>Acetylcholine receptors (AChRs) with high affinity for nicotine but no affinity for α-bungarotoxin, which have been purified from rat and chicken brains by immuno-affinity chromatography, consist of two types of subunits, α and β [1,2]. The β-subunits form the ACh binding sites [3]. Putative nicotinic AChR subunit cDNAs α₃ and α₄ have been identified by screening cDNA libraries prepared from rat PC12 cells and rat brain with cDNA probes encoding the mouse muscle AChR α-subunit. Here we determine the amino-terminal amino acid sequence of the rat brain AChR β-subunit by protein microsequencing to be the same as amino acid residues 27–43 of the protein which could be coded by α₄. Further, we present evidence consistent with a subunit stoichiometry of α₃β₂ for this neuronal nicotinic AChR.