Subtype-specific conformational landscape of NMDA receptor gating
Julia Bleier,
Philipe Ribeiro Furtado de Mendonca,
Chris H. Habrian,
Cherise Stanley,
Vojtech Vyklicky,
Ehud Y. Isacoff
Affiliations
Julia Bleier
Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
Philipe Ribeiro Furtado de Mendonca
Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
Chris H. Habrian
Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
Cherise Stanley
Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
Vojtech Vyklicky
Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
Ehud Y. Isacoff
Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Weill Neurohub, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biology & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Corresponding author
Summary: N-methyl-D-aspartate receptors are ionotropic glutamate receptors that mediate synaptic transmission and plasticity. Variable GluN2 subunits in diheterotetrameric receptors with identical GluN1 subunits set very different functional properties. To understand this diversity, we use single-molecule fluorescence resonance energy transfer (smFRET) to measure the conformations of the ligand binding domain and modulatory amino-terminal domain of the common GluN1 subunit in receptors with different GluN2 subunits. Our results demonstrate a strong influence of the GluN2 subunits on GluN1 rearrangements, both in non-agonized and partially agonized activation intermediates, which have been elusive to structural analysis, and in the fully liganded state. Chimeric analysis reveals structural determinants that contribute to these subtype differences. Our study provides a framework for understanding the conformational landscape that supports highly divergent levels of activity, desensitization, and agonist potency in receptors with different GluN2s and could open avenues for the development of subtype-specific modulators.
