After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. Neuronal AChR seems to be composed of two different types of subunits: alpha and non-alpha (beta). Alpha-2 subunit can be combined to beta-2 or beta-4 to give rise to functional receptors. The alpha-2:beta-2 nAChR complex is proposed to be a heteropentamer with two subtypes: LS (low agonist sensitivity) with a (alpha-2)3:(beta-2)2 and HS (high agonist sensitivity) with a (alpha-2)2:(beta-2)3 stoichiometry; the subtypes differ in their subunit binding interfaces which are involved in ligand binding. The disease is caused by variants affecting the gene represented in this entry. The disease may be caused by variants affecting the gene represented in this entry. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Acetylcholine receptor (TC 1.A.9.1) subfamily. Alpha-2/CHRNA2 sub-subfamily. With the use of epibatidine as high affinity ligand, an alpha-2 homopentamer has been purified and crystallized. Its physiological relevance has not been proven.