Related Experiment Video
Updated: Dec 28, 2025

A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators
Published on: February 20, 2018
Activation of G-protein Galpha subunits by receptors through Galpha-Gbeta and Galpha-Ggamma interactions
Jacqueline Cherfils1, Marc Chabre
1Laboratoire d'Enzymologie et Biochimie Structurales, UPR 9063 CNRS, 1, avenue de la Terrasse, 91198 cedex, Gif sur Yvette, France. cherfils@lebs.cnrs-gif.fr
Abstract:
Activation of the Galpha subunit of heterotrimeric GTP-binding proteins by transmembrane receptors requires the propagation of structural signals from the receptor-binding site to the nucleotide-binding site at the opposite side of the protein. In a previous model, it was suggested that the Gbeta-Ggamma dimer is tilted away from Galpha by a lever-arm motion of the Galpha N-terminal helix. Here, we propose that the motion occurs in the opposite direction, close-packing the Galpha-Gbeta interface and creating a novel interface between the helical domain of Galpha and the N terminus of Ggamma, which determines the specificity of activation.
Related Concept Videos
Activation and Inactivation of G Proteins
Transducer Mechanism: G Protein–Coupled Receptors
GPCRs are also called heptahelical,...
G Protein-coupled Receptors
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
G-protein Coupled Receptors
GPCRs Regulate Adenylyl Cylase Activity
G-Protein Gated Ion Channels
Sensory...

