Nicotinic acetylcholine receptors (nAChRs) belong to the superfamily of pentameric ligand-gated ion channels, and in neuronal tissues, are assembled from various types of α- and β-subunits. Furthermore, the subunits α4 and β2 assemble in two predominant stoichiometric forms, (α4)₂(β2)₃ and (α4)₃(β2)₂, forming receptors with dramatically different sensitivity to agonists and allosteric modulators. However, mechanisms by which the two stoichiometric forms are regulated are not known. Here, using heterologous expression in mammalian cells, single-channel patch-clamp electrophysiology, and calcium imaging, we show that the ER-resident protein NACHO selectively promotes the expression of the (α4)₂(β2)₃ stoichiometry, whereas the cytosolic molecular chaperone 14-3-3η selectively promotes the expression of the (α4)₃(β2)₂ stoichiometry. Thus, NACHO and 14-3-3η are potential physiological regulators of subunit stoichiometry, and are potential drug targets for re-balancing the stoichiometry in pathological conditions involving α4β2 nAChRs such as nicotine dependence and epilepsy.

烟碱型乙酰胆碱受体 (nAChRs) 属于五聚体配体门控离子通道的超家族，在神经元组织中，由各种类型的 α 和 β 亚基组装而成。此外，亚基 α4 和 β2 以两种主要的化学计量形式组装，(α4) ₂ (β2) ₃和 (α4) ₃ (β2) ₂，形成对激动剂和变构调节剂具有显着不同敏感性的受体。然而，调节这两种化学计量形式的机制尚不清楚。在这里，使用哺乳动物细胞中的异源表达、单通道膜片钳电生理学和钙成像，我们表明 ER 驻留蛋白 NACHO 选择性地促进 (α4) ₂ (β2)的表达₃化学计量，而细胞溶质分子伴侣 14-3-3η 选择性地促进 (α4) ₃ (β2) ₂化学计量的表达。因此，NACHO 和 14-3-3η 是亚单位化学计量的潜在生理调节剂，并且是在涉及 α4β2 nAChR 的病理条件（例如尼古丁依赖和癫痫）中重新平衡化学计量的潜在药物靶标。