Step-wise activation of a Family C GPCR.
Kumar, K.K., Wang, H., Habrian, C., Latorraca, N.R., Xu, J., O'Brien, E.S., Zhang, C., Montabana, E., Koehl, A., Marqusee, S., Isacoff, E.Y., Kobilka, B.K.(2023) Biorxiv 
- PubMed: 37693614 
- DOI: https://doi.org/10.1101/2023.08.29.555158
- Primary Citation of Related Structures:  
8T6J, 8T7H, 8T8M, 8TAO - PubMed Abstract: 
Metabotropic glutamate receptors belong to a family of G protein-coupled receptors that are obligate dimers and possess a large extracellular ligand-binding domain (ECD) that is linked via a cysteine-rich domain (CRDs) to their 7-transmembrane (TM) domain. Upon activation, these receptors undergo a large conformational change to transmit the ligand binding signal from the ECD to the G protein-coupling TM. In this manuscript, we propose a model for a sequential, multistep activation mechanism of metabotropic glutamate receptor subtype 5. We present a series of structures in lipid nanodiscs, from inactive to fully active, including agonist-bound intermediate states. Further, using bulk and single-molecule fluorescence imaging we reveal distinct receptor conformations upon allosteric modulator and G protein binding.
Organizational Affiliation: 
Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA.