Control of G protein–coupled receptor function via membrane-interacting intrinsically disordered C-terminal domains

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 121; no. 29; p. e2407744121
• Main Authors: Mancinelli, Chiara D., Marx, Dagan C., Gonzalez-Hernandez, Alberto J., Huynh, Kevin, Mancinelli, Lucia, Arefin, Anisul, Khelashvilli, George, Levitz, Joshua, Eliezer, David
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 16.07.2024
• Subjects: Arrestin; Binding; Biological Sciences; Cell Membrane - metabolism; Composition; G protein-coupled receptors; Glutamic acid receptors (metabotropic); HEK293 Cells; Humans; Intracellular; Intracellular signalling; Intrinsically Disordered Proteins - chemistry; Intrinsically Disordered Proteins - genetics; Intrinsically Disordered Proteins - metabolism; Kinases; Lipid composition; Lipids; Magnetic resonance spectroscopy; Membrane composition; Membrane proteins; Membranes; Molecular dynamics; Molecular Dynamics Simulation; Molecular structure; Mutagenesis; NMR spectroscopy; Phosphorylation; Physical Sciences; Protein Binding; Protein Domains; Proteins; Receptor mechanisms; Receptors; Receptors, G-Protein-Coupled - chemistry; Receptors, G-Protein-Coupled - metabolism; Receptors, Metabotropic Glutamate - chemistry; Receptors, Metabotropic Glutamate - genetics; Receptors, Metabotropic Glutamate - metabolism; Residues; Signal Transduction; Structure-function relationships; Transducers; GPCR; NMR; disordered protein; β-arrestin; mGluR
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.2407744121

G protein–coupled receptors (GPCRs) control intracellular signaling cascades via agonist-dependent coupling to intracellular transducers including heterotrimeric G proteins, GPCR kinases (GRKs), and arrestins. In addition to their critical interactions with the transmembrane core of active GPCRs, all three classes of transducers have also been reported to interact with receptor C-terminal domains (CTDs). An underexplored aspect of GPCR CTDs is their possible role as lipid sensors given their proximity to the membrane. CTD–membrane interactions have the potential to control the accessibility of key regulatory CTD residues to downstream effectors and transducers. Here, we report that the CTDs of two closely related family C GPCRs, metabotropic glutamate receptor 2 (mGluR2) and mGluR3, bind to membranes and that this interaction can regulate receptor function. We first characterize CTD structure with NMR spectroscopy, revealing lipid composition-dependent modes of membrane binding. Using molecular dynamics simulations and structure-guided mutagenesis, we then identify key conserved residues and cancer-associated mutations that modulate CTD–membrane binding. Finally, we provide evidence that mGluR3 transducer coupling is controlled by CTD–membrane interactions in live cells, which may be subject to regulation by CTD phosphorylation and changes in membrane composition. This work reveals an additional mechanism of GPCR modulation, suggesting that CTD–membrane binding may be a general regulatory mode throughout the broad GPCR superfamily.