PMID: 30044221

Authors:

Phulera S, Zhu H, Yu J, Claxton DP, Yoder N, Yoshioka C, Gouaux E

Title:

Cryo-EM structure of the benzodiazepine-sensitive alpha1beta1gamma2S tri-heteromeric GABAA receptor in complex with GABA.

Journal:

Elife. 2018 Jul 25;7. pii: 39383. doi: 10.7554/eLife.39383.

Abstract:

Fast inhibitory neurotransmission in mammalian nervous system is largely mediated by GABAA receptors, chloride-selective members of the superfamily of pentameric Cys-loop receptors. Native GABAA receptors are heteromeric assemblies sensitive to many important drugs, from sedatives to anesthetics and anticonvulsant agents, with mutant forms of GABAA receptors implicated in multiple neurological diseases. Despite profound importance of heteromeric GABAA receptors in neuroscience and medicine, they have proven recalcitrant to structure determination. Here we present the structure of tri-heteromeric alpha1beta1gamma2SEM GABAA receptor in complex with GABA, determined by single particle cryo-EM at 3.1-3.8 A resolution, elucidating molecular principles of receptor assembly and agonist binding. Remarkable N-linked glycosylation on the alpha1 subunit occludes the extracellular vestibule of the ion channel and is poised to modulate receptor assembly and perhaps ion channel gating. Our work provides a pathway to structural studies of heteromeric GABAA receptors and a framework for rational design of novel therapeutic agents.