title: Constitutive activation of tethered-peptide/corticotropin-releasing factor receptor chimeras.
abstract: Constitutive activity, or ligand-independent activity, of mutant G protein-coupled receptors (GPCRs) has been described extensively and implicated in the pathology of many diseases. Using the corticotropin-releasing factor (CRF) receptor and the thrombin receptor as a model, we present a ligand-dependent constitutive activation of a GPCR. A chimera in which the N-terminal domain of the CRF receptor is replaced by the amino-terminal 16 residues of CRF displays significant levels of constitutive activation. The activity, as measured by intracellular levels of cAMP, is blocked in a dose-dependent manner by the nonpeptide antagonist antalarmin. These results support a propinquity effect in CRF receptor activation, in which the amino-terminal portion of the CRF peptide is presented to the body of the receptor in the proper proximity for activation. This form of ligand-dependent constitutive activation may be of general applicability for the creation of constitutively activated GPCRs that are regulated by peptide ligands such as CRF. These chimeras may prove useful in analyzing mechanisms of receptor regulation and in the structural analysis of ligand activated receptors.
authors.affiliation: The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute for Biological Science, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Nielsen
authors.forename: L Z
authors.initials: LZ
authors.lastname: Nielsen
authors.forename: S A
authors.initials: SA
authors.lastname: Hjorth
authors.forename: M H
authors.initials: MH
authors.lastname: Perrin
authors.forename: W W
authors.initials: WW
authors.lastname: Vale
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D017433:Protein Structure, Secondary; D018019:Receptors, Corticotropin-Releasing Hormone / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D018179:Receptors, Thrombin / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D054832:Urocortins
chemical_list: D008024:Ligands; D010446:Peptide Fragments; D018019:Receptors, Corticotropin-Releasing Hormone; D018179:Receptors, Thrombin; D011993:Recombinant Fusion Proteins; D054832:Urocortins; C104416:astressin; D003346:Corticotropin-Releasing Hormone