| First Author | Wang YJ | Year | 2022 |
| Journal | J Biol Chem | Volume | 298 |
| Issue | 10 | Pages | 102423 |
| PubMed ID | 36030824 | Mgi Jnum | J:380224 |
| Mgi Id | MGI:7343042 | Doi | 10.1016/j.jbc.2022.102423 |
| Citation | Wang YJ, et al. (2022) Quantitative interactome proteomics identifies a proteostasis network for GABAA receptors. J Biol Chem 298(10):102423 |
| abstractText | Gamma-aminobutyric acid type A (GABAA) receptors are the primary inhibitory neurotransmitter-gated ion channels in the mammalian central nervous system. Maintenance of GABAA receptor protein homeostasis (proteostasis) in cells utilizing its interacting proteins is essential for the function of GABAA receptors. However, how the proteostasis network orchestrates GABAA receptor biogenesis in the endoplasmic reticulum is not well understood. Here, we employed a proteomics-based approach to systematically identify the interactomes of GABAA receptors. We carried out a quantitative immunoprecipitation-tandem mass spectrometry analysis utilizing stable isotope labeling by amino acids in cell culture. Furthermore, we performed comparative proteomics by using both WT alpha1 subunit and a misfolding-prone alpha1 subunit carrying the A322D variant as the bait proteins. We identified 125 interactors for WT alpha1-containing receptors, 105 proteins for alpha1(A322D)-containing receptors, and 54 overlapping proteins within these two interactomes. Our bioinformatics analysis identified potential GABAA receptor proteostasis network components, including chaperones, folding enzymes, trafficking factors, and degradation factors, and we assembled a model of their potential involvement in the cellular folding, degradation, and trafficking pathways for GABAA receptors. In addition, we verified endogenous interactions between alpha1 subunits and selected interactors by using coimmunoprecipitation in mouse brain homogenates. Moreover, we showed that TRIM21 (tripartite motif containing-21), an E3 ubiquitin ligase, positively regulated the degradation of misfolding-prone alpha1(A322D) subunits selectively. This study paves the way for understanding the molecular mechanisms as well as fine-tuning of GABAA receptor proteostasis to ameliorate related neurological diseases such as epilepsy. |
