Agonist- and Protein Kinase C-Induced Phosphorylation Have Similar Functional Consequences for Gastrin-Releasing Peptide Receptor Signaling via Gq
| Autor: | James F. Battey, Kirk L. Ives, Pei-Wen Chen, Patrick J. Cahill, Roxanne A. Ally, Iman Eltounsi, Mark R. Hellmich, Elie Traube, Glenn S. Kroog |
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| Rok vydání: | 2003 |
| Předmět: |
inorganic chemicals
Agonist medicine.drug_class Molecular Sequence Data macromolecular substances environment and public health Mice Arrestin medicine Gastrin-releasing peptide receptor Animals Amino Acid Sequence Phosphorylation Protein Kinase C Protein kinase C G protein-coupled receptor Pharmacology Mice Inbred BALB C biology Kinase Beta adrenergic receptor kinase Biological Transport 3T3 Cells Molecular biology Protein Structure Tertiary Cell biology Receptors Bombesin enzymes and coenzymes (carbohydrates) Mutation biology.protein bacteria Molecular Medicine Bombesin Calcium Signal Transduction |
| Zdroj: | Molecular Pharmacology. 64:890-904 |
| ISSN: | 1521-0111 0026-895X |
| DOI: | 10.1124/mol.64.4.890 |
| Popis: | Acute desensitization of many guanine nucleotide-binding protein-coupled receptors (GPCRs) requires receptor phosphorylation and subsequent binding of an arrestin. GPCRs are substrates for phosphorylation by several classes of kinases. Gastrin-releasing peptide receptor (GRPr) is phosphorylated by a kinase other than protein kinase C (PKC) after exposure to agonist and is also a substrate for PKC-dependent phosphorylation after treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA). Using GRPr mutants, we examined receptor domains required for agonist- and TPA-induced phosphorylation of GRPr and consequences of these phosphorylation events on GRPr signaling via Gq. Agonist- and TPA-stimulated GRPr phosphorylation in cells require an intact carboxyl terminal domain (CTD). GRPr is phosphorylated in vitro by GPCR kinase 2 (GRK2) and multiple PKC isoforms. An intact DRY motif is required for agonist-stimulated phosphorylation in cells, and agonist-dependent GRK2 phosphorylation in vitro. Although GRPr CTD mutants do not show enhanced in vitro coupling to Gq relative to intact GRPr, CTD mutants have more potent Gq-dependent signaling in cells. Acute desensitization involves CTD-independent processes because desensitization can precede ligand binding in intact GRPr and CTD mutants. TPA-mediated impairment of GRPr-Gq signaling in cells also requires an intact CTD. Similar to GRK2 phosphorylation, PKC phosphorylation reduces GRPr-Gq coupling by approximately 80% in vitro. Arrestin translocation to plasma membrane requires agonist, an intact DRY motif, and GRPr phosphorylation. Therefore, agonist- and PKC-induced GRPr phosphorylation sites are in nearby regions of the receptor, and phosphorylation at both sites has similar functional consequences for Gq signaling. |
| Databáze: | OpenAIRE |
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