title: Biased signaling pathways in β2-adrenergic receptor characterized by 19F-NMR.
abstract: Extracellular 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.
authors.affiliation: Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Liu
authors.forename: Reto
authors.initials: R
authors.lastname: Horst
authors.forename: Vsevolod
authors.initials: V
authors.lastname: Katritch
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Stevens
authors.forename: Kurt
authors.initials: K
authors.lastname: Wüthrich
mesh_terms: D058666:Adrenergic beta-2 Receptor Agonists / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D019390:Arrestins / Q000378:metabolism; D001665:Binding Sites; D002227:Carbazoles / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000077261:Carvedilol; D003593:Cytoplasm / Q000737:chemistry; D054333:Drug Partial Agonism; D005461:Fluorine; D007528:Isoetharine / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D007545:Isoproterenol / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011412:Propanolamines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D018343:Receptors, Adrenergic, beta-2 / Q000737:chemistry* / Q000378:metabolism*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D000071557:beta-Arrestins
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D019390:Arrestins; D002227:Carbazoles; D008024:Ligands; D011412:Propanolamines; D018343:Receptors, Adrenergic, beta-2; D000071557:beta-Arrestins; D000077261:Carvedilol; D005461:Fluorine; D007545:Isoproterenol; D007528:Isoetharine