Work

Cryo-EM structures of the triheteromeric NMDA receptor and its allosteric modulation

Year: 2017

Type: article

Abstract: -methyl-d-aspartate receptors (NMDARs) are heterotetrameric ion channels assembled as diheteromeric or triheteromeric complexes. Here, we report structures of the triheteromeric GluN1/GluN2A/GluN2B receptor in the absence or presence of the GluN2B-specific allosteric modulator Ro 25-6981 (Ro), determined by cryogenic electron microscopy (cryo-EM). In the absence of Ro, the GluN2A and GluN2B amino-terminal domains (ATDs) adopt "closed" and "open" clefts, respectively. Upon binding Ro, the GluN2B ATD clamshell transitions from an open to a closed conformation. Consistent with a predominance of the GluN2A subunit in ion channel gating, the GluN2A subunit interacts more extensively with GluN1 subunits throughout the receptor, in comparison with the GluN2B subunit. Differences in the conformation of the pseudo-2-fold-related GluN1 subunits further reflect receptor asymmetry. The triheteromeric NMDAR structures provide the first view of the most common NMDA receptor assembly and show how incorporation of two different GluN2 subunits modifies receptor symmetry and subunit interactions, allowing each subunit to uniquely influence receptor structure and function, thus increasing receptor complexity.

Source: Science

DOI: 10.1126/science.aal3729

Authors: Wei Lü, Juan Du, April Goehring, Eric Gouaux

Institutions: Oregon Health & Science University, Vollum Institute, Howard Hughes Medical Institute

Language: English

Topic: Neuroscience and Neuropharmacology Research

Subfield: Cellular and Molecular Neuroscience

Field: Neuroscience

Domain: Life Sciences

Open Access status: green

Funders: Howard Hughes Medical Institute, National Institutes of Health, National Institute of Neurological Disorders and Stroke

Awards: G5202540343, 3D Structure and Function of Ligand-Gated Ion Channels