Heteromeric Neuronal Nicotinic Acetylcholine Receptors with Mutant <i>β</i> Subunits Acquire Sensitivity to <i>α</i>7-Selective Positive Allosteric Modulators
作者:Clare Stokes、Sumanta Garai、Abhijit R. Kulkarni、Lucas N. Cantwell、Colleen M. Noviello、Ryan E. Hibbs、Nicole A. Horenstein、Khalil A. Abboud、Ganesh A. Thakur、Roger L. Papke
DOI:10.1124/jpet.119.259499
日期:2019.8
Homomeric α7 nicotinic acetylcholine receptors (nAChR) have an intrinsically low probability of opening that can be overcome by α7-selective positive allosteric modulators (PAMs), which bind at a site involving the second transmembrane domain (TM2). Mutation of a methionine that is unique to α7 at the 15' position of TM2 to leucine, the residue in most other nAChR subunits, largely eliminates the activity
同源的α7烟碱乙酰胆碱受体(nAChR)本质上具有较低的打开可能性,可以通过α7选择性正构构变数(PAM)克服,后者在涉及第二个跨膜结构域(TM2)的位点结合。在大多数其他nAChR亚基中的残基,TM2的15'位置上的α7特有的甲硫氨酸突变为亮氨酸,很大程度上消除了此类PAM的活性。我们测试了反向突变(L15'M)在含有α4和β2(这是大脑中最丰富的nAChR亚基)的异聚nAChR受体中的作用。发现含有这些突变的受体被α7PAM 3a,4,5,9b-四氢-4-(1-萘基)-3H-环戊烷[c]喹啉-8-磺酰胺(TQS)强烈增强,但对它们不敏感。替代PAM 1-(5-chloro-2,4-二甲氧基苯基)-3-(5-甲基异恶唑-3-基)-脲。对于TQS敏感性,β2亚基中突变的存在是必要和充分的。α4亚基突变的主要作用是减少对单独应用的乙酰胆碱的反应。对TQS的敏感性仅需要单个突变体β亚基,而不管