Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.
Cells. 2023 Dec 20;13(1):14. doi: 10.3390/cells13010014.
GABA receptors are the major inhibitory receptors in the brain. They are hetero-pentamers with a composition of predominantly two α, two β, and one γ or δ subunit. Of the six α subunit genes, the α5 subunit displays a limited spatial expression pattern and is known to mediate both phasic and tonic inhibition. In this study, using immunoaffinity-based proteomics, we identified the α5 subunit containing receptor complexes in the hippocampus and olfactory bulb. The α1-α5 interaction was identified in both brain regions, albeit with significantly different stoichiometries. In line with this, reverse IPs using anti-α1 antibodies showed the α5-α1 co-occurrence and validated the quantitative difference. In addition, we showed that the association of Neuroligin 2 with α1-containing receptors was much higher in the olfactory bulb than in the hippocampus, which was confirmed using blue native gel electrophoresis and quantitative mass spectrometry. Finally, immunocytochemical staining revealed a co-localization of α1 and α5 subunits in the post-synaptic puncta in the hippocampus.
GABA 受体是大脑中的主要抑制性受体。它们是异戊五聚体，主要由两个 α、两个 β 和一个 γ 或 δ 亚基组成。在六个 α 亚基基因中，α5 亚基显示出有限的空间表达模式，已知介导相分离和紧张性抑制。在这项研究中，我们使用基于免疫亲和的蛋白质组学方法，鉴定了海马体和嗅球中含有 α5 亚基的受体复合物。α1-α5 相互作用在两个脑区都被鉴定出来，尽管其化学计量比有显著差异。与此一致的是，使用抗-α1 抗体的反向 IP 显示了 α5-α1 的共出现，并验证了定量差异。此外，我们还表明，神经黏附素 2 与含有 α1 的受体的结合在嗅球中比在海马体中高得多，这一点通过蓝色 native 凝胶电泳和定量质谱得到了证实。最后，免疫细胞化学染色显示 α1 和 α5 亚基在海马体的突触后点共定位。
