Biased Signaling Pathways in β 2 -Adrenergic Receptor Characterized by 19 F-NMR
2012; American Association for the Advancement of Science; Volume: 335; Issue: 6072 Linguagem: Inglês
10.1126/science.1215802
ISSN1095-9203
AutoresJeffrey J. Liu, Reto Horst, Vsevolod Katritch, Raymond C. Stevens, Kurt Wüthrich,
Tópico(s)Neuroscience and Neuropharmacology Research
ResumoExtracellular ligand binding to G protein-coupled receptors (GPCRs) modulates G protein and β-arrestin signaling by changing the conformational states of the cytoplasmic region of the receptor. Using site-specific (19)F-NMR (fluorine-19 nuclear magnetic resonance) labels in the β(2)-adrenergic receptor (β(2)AR) in complexes with various ligands, we observed that the cytoplasmic ends of helices VI and VII adopt two major conformational states. Changes in the NMR signals reveal that agonist binding primarily shifts the equilibrium toward the G protein-specific active state of helix VI. In contrast, β-arrestin-biased ligands predominantly impact the conformational states of helix VII. The selective effects of different ligands on the conformational equilibria involving helices VI and VII provide insights into the long-range structural plasticity of β(2)AR in partial and biased agonist signaling.
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