PMID- 30602789 OWN - NLM STAT- MEDLINE DCOM- 20190610 LR - 20220131 IS - 1476-4687 (Electronic) IS - 0028-0836 (Print) IS - 0028-0836 (Linking) VI - 565 IP - 7740 DP - 2019 Jan TI - Cryo-EM structure of the human alpha1beta3gamma2 GABA(A) receptor in a lipid bilayer. PG - 516-520 LID - 10.1038/s41586-018-0833-4 [doi] AB - Type A gamma-aminobutyric acid (GABA(A)) receptors are pentameric ligand-gated ion channels and the main drivers of fast inhibitory neurotransmission in the vertebrate nervous system(1,2). Their dysfunction is implicated in a range of neurological disorders, including depression, epilepsy and schizophrenia(3,4). Among the numerous assemblies that are theoretically possible, the most prevalent in the brain are the alpha1beta2/3gamma2 GABA(A) receptors(5). The beta3 subunit has an important role in maintaining inhibitory tone, and the expression of this subunit alone is sufficient to rescue inhibitory synaptic transmission in beta1-beta3 triple knockout neurons(6). So far, efforts to generate accurate structural models for heteromeric GABA(A) receptors have been hampered by the use of engineered receptors and the presence of detergents(7-9). Notably, some recent cryo-electron microscopy reconstructions have reported 'collapsed' conformations(8,9); however, these disagree with the structure of the prototypical pentameric ligand-gated ion channel the Torpedo nicotinic acetylcholine receptor(10,11), the large body of structural work on homologous homopentameric receptor variants(12) and the logic of an ion-channel architecture. Here we present a high-resolution cryo-electron microscopy structure of the full-length human alpha1beta3gamma2L-a major synaptic GABA(A) receptor isoform-that is functionally reconstituted in lipid nanodiscs. The receptor is bound to a positive allosteric modulator 'megabody' and is in a desensitized conformation. Each GABA(A) receptor pentamer contains two phosphatidylinositol-4,5-bisphosphate molecules, the head groups of which occupy positively charged pockets in the intracellular juxtamembrane regions of alpha1 subunits. Beyond this level, the intracellular M3-M4 loops are largely disordered, possibly because interacting post-synaptic proteins are not present. This structure illustrates the molecular principles of heteromeric GABA(A) receptor organization and provides a reference framework for future mechanistic investigations of GABAergic signalling and pharmacology. FAU - Laverty, Duncan AU - Laverty D AD - MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK. dlaverty@mrc-lmb.cam.ac.uk. FAU - Desai, Rooma AU - Desai R AD - Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. FAU - Uchanski, Tomasz AU - Uchanski T AD - Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium. AD - VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium. FAU - Masiulis, Simonas AU - Masiulis S AD - MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK. FAU - Stec, Wojciech J AU - Stec WJ AD - Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. FAU - Malinauskas, Tomas AU - Malinauskas T AD - Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK. FAU - Zivanov, Jasenko AU - Zivanov J AD - MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK. FAU - Pardon, Els AU - Pardon E AD - Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium. AD - VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium. FAU - Steyaert, Jan AU - Steyaert J AD - Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium. AD - VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium. FAU - Miller, Keith W AU - Miller KW AD - Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. kwmiller@mgh.harvard.edu. FAU - Aricescu, A Radu AU - Aricescu AR AD - MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK. radu@mrc-lmb.cam.ac.uk. AD - Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK. radu@mrc-lmb.cam.ac.uk. LA - eng GR - MC_EX_MR/L009609/2/MRC_/Medical Research Council/United Kingdom GR - MR/L009609/1/MRC_/Medical Research Council/United Kingdom GR - MC_UP_1201/15/MRC_/Medical Research Council/United Kingdom GR - MC_UP_A025_1013/MRC_/Medical Research Council/United Kingdom GR - P01 GM058448/GM/NIGMS NIH HHS/United States GR - A14414/CRUK_/Cancer Research UK/United Kingdom PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20190102 PL - England TA - Nature JT - Nature JID - 0410462 RN - 0 (Lipid Bilayers) RN - 0 (Phosphatidylinositol 4,5-Diphosphate) RN - 0 (Protein Isoforms) RN - 0 (Receptors, GABA-A) SB - IM CIN - Nature. 2019 Jan;565(7740):436-438. PMID: 30666053 MH - Allosteric Regulation MH - Amino Acid Sequence MH - Binding Sites MH - *Cryoelectron Microscopy MH - Electric Conductivity MH - Humans MH - Lipid Bilayers/*chemistry MH - Models, Molecular MH - Molecular Docking Simulation MH - Nanostructures/chemistry/ultrastructure MH - Phosphatidylinositol 4,5-Diphosphate/chemistry/metabolism MH - Protein Isoforms/chemistry/metabolism/ultrastructure MH - Protein Structure, Quaternary MH - Receptors, GABA-A/*chemistry/metabolism/*ultrastructure PMC - PMC6364807 MID - EMS80767 COIS- The authors declare no competing interests. EDAT- 2019/01/04 06:00 MHDA- 2019/06/14 06:00 PMCR- 2019/07/02 CRDT- 2019/01/04 06:00 PHST- 2018/06/28 00:00 [received] PHST- 2018/12/03 00:00 [accepted] PHST- 2019/01/04 06:00 [pubmed] PHST- 2019/06/14 06:00 [medline] PHST- 2019/01/04 06:00 [entrez] PHST- 2019/07/02 00:00 [pmc-release] AID - 10.1038/s41586-018-0833-4 [pii] AID - 10.1038/s41586-018-0833-4 [doi] PST - ppublish SO - Nature. 2019 Jan;565(7740):516-520. doi: 10.1038/s41586-018-0833-4. Epub 2019 Jan 2.