J Clin Invest. 2020 Nov 2;130(11):6158-6170. doi: 10.1172/JCI140311.
The α6β4 nicotinic acetylcholine receptor (nAChR) is enriched in dorsal root ganglia neurons and is an attractive non-opioid therapeutic target for pain. However, difficulty expressing human α6β4 receptors in recombinant systems has precluded drug discovery. Here, genome-wide screening identified accessory proteins that enable reconstitution of human α6β4 nAChRs. BARP, an auxiliary subunit of voltage-dependent calcium channels, promoted α6β4 surface expression while IRE1α, an unfolded protein response sensor, enhanced α6β4 receptor assembly. Effects on α6β4 involve BARP's N-terminal region and IRE1α's splicing of XBP1 mRNA. Furthermore, clinical efficacy of nicotinic agents in relieving neuropathic pain best correlated with their activity on α6β4. Finally, BARP-knockout, but not NACHO-knockout mice lacked nicotine-induced antiallodynia, highlighting the functional importance of α6β4 in pain. These results identify roles for IRE1α and BARP in neurotransmitter receptor assembly and unlock drug discovery for the previously elusive α6β4 receptor.
α6β4 型烟碱型乙酰胆碱受体 (nAChR) 在背根神经节神经元中丰富表达，是一种有吸引力的非阿片类疼痛治疗靶点。然而，在重组系统中表达人源 α6β4 受体的困难阻碍了药物的发现。在这里，全基因组筛选确定了辅助蛋白，这些蛋白能够重建人源 α6β4 nAChR。电压依赖性钙通道的辅助亚基 BARP 促进了 α6β4 的表面表达，而未折叠蛋白反应传感器 IRE1α 增强了 α6β4 受体的组装。对 α6β4 的影响涉及 BARP 的 N 端区域和 IRE1α 对 XBP1 mRNA 的剪接。此外，烟碱类药物缓解神经性疼痛的临床疗效与它们对 α6β4 的活性密切相关。最后，BARP 敲除，但不是 NACHO 敲除小鼠缺乏尼古丁诱导的抗痛觉过敏，突出了 α6β4 在疼痛中的功能重要性。这些结果确定了 IRE1α 和 BARP 在神经递质受体组装中的作用，并为以前难以捉摸的 α6β4 受体的药物发现提供了线索。
