The third intracellular loop of D1 and D5 dopaminergic receptors dictates their subtype-specific PKC-induced sensitization and desensitization in a receptor conformation-dependent manner
Autor: | Bianca Plouffe, Xiaodi Yang, Mario Tiberi |
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Rok vydání: | 2011 |
Předmět: |
medicine.medical_specialty
Gs alpha subunit Indoles Protein Conformation medicine.medical_treatment Dopamine Recombinant Fusion Proteins Amino Acid Motifs Enzyme Activators Stimulation Maleimides 03 medical and health sciences 0302 clinical medicine Internal medicine medicine Cyclic AMP Humans Receptors Dopamine D5 Phosphorylation Receptor Sensitization Protein Kinase C 030304 developmental biology Desensitization (medicine) G protein-coupled receptor 0303 health sciences Dose-Response Relationship Drug Chemistry Receptors Dopamine D1 Colforsin Wild type Cell Biology Cell biology Isoenzymes Endocrinology medicine.anatomical_structure HEK293 Cells Dopamine receptor Tetradecanoylphorbol Acetate 030217 neurology & neurosurgery Adenylyl Cyclases |
Zdroj: | Cellular signalling. 24(1) |
ISSN: | 1873-3913 |
Popis: | We previously showed that phorbol-12-myristate-13-acetate (PMA) mediates a robust PKC-dependent sensitization and desensitization of the highly homologous human Gs protein and adenylyl cyclase (AC)-linked D1 (hD1R) and D5 (hD5R) dopaminergic receptors, respectively. Here, we demonstrate using forskolin-mediated AC stimulation that PMA-mediated hD1R sensitization and hD5R desensitization is not associated with changes in AC activity. We next employed a series of chimeric hD1R and hD5R to delineate the underlying structural determinants dictating the subtype-specific regulation of human D1-like receptors by PMA. We first used chimeric receptors in which the whole terminal region (TR) spanning from the extracellular face of transmembrane domain 6 to the end of cytoplasmic tail (CT) or CT alone were exchanged between hD1R and hD5R. CT and TR swaps lead to chimeric hD1R and hD5R retaining PMA-induced sensitization and desensitization of wild type parent receptors. In striking contrast, hD1R sensitization and hD5R desensitization mediated by PMA are correspondingly switched to PMA-induced receptor desensitization and sensitization following the IL3 swap between hD1R and hD5R. Cell treatment with the PKC blocker, Go6983, inhibits PMA-induced regulation of these chimeric receptors in a similar fashion to wild type receptors. Further studies with chimeras constructed by exchanging IL3 and TR show that PMA-induced regulation of these chimeras remains fully switched relative to their respective wild type parent receptor. Interestingly, results obtained with the exchange of IL3 and TR also reveal that the D1-like subtype-specific regulation by PMA, while fully dictated by IL3, can be modulated in a receptor conformation-dependent manner. Overall, our results strongly suggest that IL3 is the critical determinant underlying the subtype-specific regulation of human D1-like receptor responsiveness by PKC. |
Databáze: | OpenAIRE |
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