Distinct Residues in the Carboxyl Tail Mediate Agonist-induced Desensitization and Internalization of the Human Dopamine D1 Receptor
| Autor: | Brian F. O'Dowd, Susan R. George, Miles D. Thompson, Marek Sawzdargo, Michael Lamey, Hong Chi, George Varghese |
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| Rok vydání: | 2002 |
| Předmět: |
Agonist
medicine.drug_class media_common.quotation_subject Molecular Sequence Data CHO Cells Biology Biochemistry Serine Structure-Activity Relationship Dopamine receptor D1 Cricetinae Homologous desensitization medicine Animals Humans Amino Acid Sequence Phosphorylation Receptor Internalization Molecular Biology media_common Receptors Dopamine D1 Chinese hamster ovary cell Cell Biology Cyclic AMP-Dependent Protein Kinases Molecular biology Cell biology beta-Adrenergic Receptor Kinases Dopamine Agonists Receptors Adrenergic beta-2 |
| Zdroj: | Journal of Biological Chemistry. 277:9415-9421 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m111811200 |
| Popis: | We have shown in a previous study that desensitization and internalization of the human dopamine D1 receptor following short-term agonist exposure are mediated by temporally and biochemically distinct mechanisms. In the present study, we have used site-directed mutagenesis to remove potential phosphorylation sites in the third intracellular loop and carboxyl tail of the dopamine D1 receptor to study these processes. Mutant D1 receptors were stably transfected into Chinese hamster ovary cells, and kinetic parameters were measured. Mutations of Ser/Thr residues to alanine in the carboxyl tail demonstrated that the single substitution of Thr-360 abolished agonist-induced phosphorylation and desensitization of the receptor. Isolated mutation of the adjacent glutamic acid Glu-359 also abolished agonist-induced phosphorylation and desensitization of the receptor. These data suggest that Thr-360 in conjunction with Glu-359 may comprise a motif necessary for GRK2-mediated phosphorylation and desensitization. Agonist-induced internalization was not affected with mutation of either the Thr-360 or the Glu-359 residues. However, receptors with Ser/Thr residues mutated in the distal carboxyl tail (Thr-446, Thr-439, and Ser-431) failed to internalize in response to agonist activation, but were able to desensitize normally. These results indicate that agonist-induced desensitization and internalization are regulated by separate and distinct serine and threonine residues within the carboxyl tail of the human dopamine D1 receptor. |
| Databáze: | OpenAIRE |
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