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

Abstract

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