A reporter mutation approach shows incorporation of the "orphan" subunit β3 into a functional nicotinic receptor
A reporter mutation approach shows incorporation of the "orphan" subunit β3 into a functional nicotinic receptor
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DOI：
10.1074/jbc.273.25.15317
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发表时间：
1998-06-19
影响因子：
4.8
通讯作者：
Sivilotti, LG
中科院分区：
文献类型：
--
作者：
Groot-Kormelink, PJ;Luyten, WHML;Sivilotti, LG
我们研究了神经元型尼古丁亚基β3是否参与功能性重组受体的组装，虽然β3在中枢神经系统的多个区域表达，但当它与一个α或另一个β尼古丁亚基一起异源表达时，并不形成功能性受体。我们在人β3亚单位中插入了一个报告突变(V273T)，如果将其整合到功能性受体中，将有望增加其激动剂的敏感性和对部分激动剂的最大反应。在非洲爪哇卵母细胞中同时表达突变的β3(V273T)和α3和β4亚基，与α3β4受体相比，所产生的尼古丁受体的性质发生了预期的变化。这表明一些受体结合了突变的β3亚单位，作为“三联体”α3β4β3受体的一部分。三联体受体的比例取决于注射的α3：β4：β3cRNA的比例。我们的结论是，与相关的α5亚基一样，β3亚基只有在与α和β亚基一起表达的情况下才能形成功能受体。
We have investigated whether the neuronal nicotinic subunit beta 3 can participate in the assembly of functional recombinant receptors, Although beta 3 is expressed in several areas of the central nervous system, it does not form functional receptors when expressed heterologously together with an alpha or another beta nicotinic subunit, We inserted into the human beta 3 subunit a reporter mutation (V273T), which, if incorporated into a functional receptor, would be expected to increase its agonist sensitivity and maximum response to partial agonists, Expressing the mutant beta 3(V273T) in Xenopus oocytes together with both the alpha 3 and the beta 4 subunits resulted in the predicted changes in the properties of the resulting nicotinic receptor when compared with those of alpha 3 beta 4 receptors. This indicated that some of the receptors incorporated the mutant beta 3 subunit, as part of a "triplet" alpha 3 beta 4 beta 3 receptor. The proportion of triplet receptors was dependent on the ratios of the alpha 3:beta 4:beta 3 cRNA injected. We conclude that, like the related alpha 5 subunit, the beta 3 subunit can form functional receptors only if expressed together with both alpha and beta subunits.