Analyzing the mechanisms that facilitate the subtype-specific assembly of γ-aminobutyric acid type A receptors.
Analyzing the mechanisms that facilitate the subtype-specific assembly of γ-aminobutyric acid type A receptors.
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DOI：
10.3389/fnmol.2022.1017404
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发表时间：
2022
影响因子：
4.8
通讯作者：
Moss, Stephen J.
中科院分区：
文献类型：
--
作者：
Choi, Catherine;Smalley, Joshua L.;Lemons, Abigail H. S.;Ren, Qiu;Bope, Christopher E.;Dengler, Jake S.;Davies, Paul A.;Moss, Stephen J.
抑制信号受损是许多神经精神和神经发育障碍的病理生理学基础，包括自闭症谱系障碍和癫痫。神经元抑制由突触和突触外γ-氨基丁酸A型受体（GABAARs）调节，它们分别介导相位抑制和强直抑制。这两种GABAAR亚型在功能、配体敏感性和生理特性上有所不同。重要的是，它们含有不同的α亚基亚型：突触GABAARs含有α1 - 3亚基，而突触外GABAARs含有α4 - 6亚基。虽然亚基组成对于突触和突触外GABAAR亚型在抑制中的不同作用至关重要，但亚型特异性组装的分子机制尚未阐明。为了解决这一问题，我们从成年小鼠前脑中纯化了内源性α1-和α4- GABAARs，并利用液相色谱-串联质谱（LC-MS/MS）和定量分析技术检测了它们的亚基组成和相互作用蛋白。我们发现α1和α4亚基形成了不同的GABAARs群体，并与不同的结合蛋白相互作用。我们还发现，与α1和α4亚基共同纯化的β3亚基在两种受体亚型中对408和409丝氨酸（S408/9）的磷酸化水平不同。为了了解S408/9在含α1-和α4的GABAARs组装中的作用，我们利用LC-MS/MS和定量分析检测了S408/9A（丙氨酸）敲入突变对这两种受体亚型亚基组成的影响。我们发现S408/9A突变导致新的含有α1α4的GABAARs的形成。此外，在S408/9A突变体中，α4亚基的质膜表达增加，而其在内质网中的保留减少。这些发现表明，S408/9在决定GABAARs亚型特异性组装中起关键作用，从而影响神经元抑制的效果。
Impaired inhibitory signaling underlies the pathophysiology of many neuropsychiatric and neurodevelopmental disorders including autism spectrum disorders and epilepsy. Neuronal inhibition is regulated by synaptic and extrasynaptic γ-aminobutyric acid type A receptors (GABAARs), which mediate phasic and tonic inhibition, respectively. These two GABAAR subtypes differ in their function, ligand sensitivity, and physiological properties. Importantly, they contain different α subunit isoforms: synaptic GABAARs contain the α1–3 subunits whereas extrasynaptic GABAARs contain the α4–6 subunits. While the subunit composition is critical for the distinct roles of synaptic and extrasynaptic GABAAR subtypes in inhibition, the molecular mechanism of the subtype-specific assembly has not been elucidated. To address this issue, we purified endogenous α1- and α4-containing GABAARs from adult murine forebrains and examined their subunit composition and interacting proteins using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and quantitative analysis. We found that the α1 and α4 subunits form separate populations of GABAARs and interact with distinct sets of binding proteins. We also discovered that the β3 subunit, which co-purifies with both the α1 and α4 subunits, has different levels of phosphorylation on serines 408 and 409 (S408/9) between the two receptor subtypes. To understand the role S408/9 plays in the assembly of α1- and α4-containing GABAARs, we examined the effects of S408/9A (alanine) knock-in mutation on the subunit composition of the two receptor subtypes using LC-MS/MS and quantitative analysis. We discovered that the S408/9A mutation results in the formation of novel α1α4-containing GABAARs. Moreover, in S408/9A mutants, the plasma membrane expression of the α4 subunit is increased whereas its retention in the endoplasmic reticulum is reduced. These findings suggest that S408/9 play a critical role in determining the subtype-specific assembly of GABAARs, and thus the efficacy of neuronal inhibition.
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影响因子：
5.3
作者：
Jovanovic, JN;Thomas, P;Moss, SJ
通讯作者：
Moss, SJ
影响因子：
4.8
作者：
Connolly, CN;Krishek, BJ;Moss, SJ
通讯作者：
Moss, SJ
影响因子：
4.7
作者：
Adams JM;Thomas P;Smart TG
通讯作者：
Smart TG
DOI：
10.1074/mcp.m111.011445
发表时间：
2012-01
期刊：
Molecular & cellular proteomics : MCP
影响因子：
--
作者：
Chen ZW;Fuchs K;Sieghart W;Townsend RR;Evers AS
通讯作者：
Evers AS
DOI：
10.1073/pnas.1705043114
发表时间：
2017-08-08
影响因子：
11.1
作者：
Han, Boran;Zhou, Ruobo;Zhuang, Xiaowei
通讯作者：
Zhuang, Xiaowei