Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania, United States of America.
PLoS One. 2013 Apr 24;8(4):e62246. doi: 10.1371/journal.pone.0062246. Print 2013.
Functional α7 nicotinic acetylcholine receptors (AChRs) do not assemble efficiently in cells transfected with α7 subunits unless the cells are also transfected with the chaperone protein RIC-3. Despite the presence of RIC-3, large amounts of these subunits remain improperly assembled. Thus, additional chaperone proteins are probably required for efficient assembly of α7 AChRs. Cholinergic ligands can act as pharmacological chaperones to promote assembly of mature AChRs and upregulate the amount of functional AChRs. In addition, we have found that the chemical chaperones 4-phenylbutyric acid (PBA) and valproic acid (VPA) greatly increase the amount of functional α7 AChRs produced in a cell line expressing both α7 and RIC-3. Increased α7 AChR expression allows assay of drug action using a membrane potential-sensitive fluorescent indicator. Both PBA and VPA also increase α7 expression in the SH-SY5Y neuroblastoma cell line that endogenously expresses α7 AChRs. VPA increases expression of endogenous α7 AChRs in hippocampal neurons but PBA does not. RIC-3 is insufficient for optimal assembly of α7 AChRs, but provides assay conditions for detecting additional chaperones. Chemical chaperones are a useful pragmatic approach to express high levels of human α7 AChRs for drug selection and characterization and possibly to increase α7 expression in vivo.
功能性α7 烟碱型乙酰胆碱受体（AChRs）在转染α7 亚基的细胞中不能有效地组装，除非这些细胞也被转染了伴侣蛋白 RIC-3。尽管存在 RIC-3，但大量的这些亚基仍然组装不正确。因此，可能需要其他伴侣蛋白来有效地组装α7 AChRs。胆碱能配体可以作为药理学伴侣蛋白，促进成熟 AChRs 的组装，并上调功能性 AChRs 的数量。此外，我们发现化学伴侣蛋白 4-苯基丁酸（PBA）和丙戊酸（VPA）极大地增加了在表达α7 和 RIC-3 的细胞系中产生的功能性α7 AChRs 的数量。增加α7 AChR 的表达可以使用膜电位敏感的荧光指示剂来检测药物的作用。PBA 和 VPA 都能增加内源性表达α7 AChRs 的 SH-SY5Y 神经母细胞瘤细胞系中的α7 表达。VPA 增加海马神经元中内源性α7 AChRs 的表达，但 PBA 没有。RIC-3 不足以使α7 AChRs 达到最佳组装，但为检测其他伴侣蛋白提供了检测条件。化学伴侣蛋白是一种实用的方法，可以表达高水平的人α7 AChRs 用于药物筛选和表征，并且可能增加体内α7 的表达。
