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bioRxiv · 10.1101/660837

Structural insights into ligand efficacy and activation of the glucagon receptor

Hilger, D.·Krishna Kumar, K.·Hu, H.·Pedersen, M. F.·Giehm, L.·Mathiesen, J. M.·Skiniotis, G.·Kobilka, B. K.
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Abstract

The glucagon receptor family comprises Class B G protein-coupled receptors (GPCRs) that play a crucial role in regulating blood sugar levels. Receptors of this family represent important therapeutic targets for the treatment of diabetes and obesity. Despite intensive structural studies, we only have a poor understanding of the mechanism of peptide hormone-induced Class B receptor activation. This process involves the formation of a sharp kink in transmembrane helix 6 that moves out to allow formation of the nucleotide-free G protein complex. Here, we present the cryo-EM structure of the glucagon receptor (GCGR), a prototypical Class B GPCR, in complex with an engineered soluble glucagon derivative and the heterotrimeric G-protein, Gs. Comparison with the previously determined crystal structures of GCGR bound to a partial agonist reveals a structural framework to explain the molecular basis of ligand efficacy that is further supported by mutagenesis data.

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Hilger, D., Krishna Kumar, K., Hu, H., Pedersen, M. F., Giehm, L., Mathiesen, J. M., Skiniotis, G., Kobilka, B. K.. 2019-06-05. Structural insights into ligand efficacy and activation of the glucagon receptor. https://doi.org/10.1101/660837

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