Mutations in the 'DRY' motif of the CB1 cannabinoid receptor result in biased receptor variants
Autor: | Dániel Tímár, László Hunyady, András Tóth, Pál Gyombolai, Gábor Turu |
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Rok vydání: | 2014 |
Předmět: |
Agonist
GTPase-activating protein G protein medicine.drug_class Arrestins Amino Acid Motifs Mutation Missense CHO Cells Biology GTP-Binding Protein alpha Subunits Gi-Go Endocrinology Cricetulus Receptor Cannabinoid CB1 Heterotrimeric G protein Cricetinae medicine Animals Humans 5-HT5A receptor Receptor Molecular Biology beta-Arrestins G protein-coupled receptor kinase Molecular biology beta-Arrestin 2 Rats Protein Transport beta-Arrestin 1 Signal transduction HeLa Cells |
Zdroj: | Journal of molecular endocrinology. 54(1) |
ISSN: | 1479-6813 |
Popis: | The role of the highly conserved ‘DRY’ motif in the signaling of the CB1cannabinoid receptor (CB1R) was investigated by inducing single-, double-, and triple-alanine mutations into this site of the receptor. We found that the CB1R-R3.50A mutant displays a partial decrease in its ability to activate heterotrimeric Goproteins (∼80% of WT CB1R (CB1R-WT)). Moreover, this mutant showed an enhanced basal β-arrestin2 (β-arr2) recruitment. More strikingly, the double-mutant CB1R-D3.49A/R3.50A was biased toward β-arrs, as it gained a robustly increased β-arr1 and β-arr2 recruitment ability compared with the WT receptor, while its G-protein activation was decreased. In contrast, the double-mutant CB1R-R3.50A/Y3.51A proved to be G-protein-biased, as it was practically unable to recruit β-arrs in response to agonist stimulus, while still activating G-proteins, although at a reduced level (∼70% of CB1R-WT). Agonist-induced ERK1/2 activation of the CB1R mutants showed a good correlation with their β-arr recruitment ability but not with their G-protein activation or inhibition of cAMP accumulation. Our results suggest that G-protein activation and β-arr binding of the CB1R are mediated by distinct receptor conformations, and the conserved ‘DRY’ motif plays different roles in the stabilization of these conformations, thus mediating both G-protein- and β-arr-mediated functions of CB1R. |
Databáze: | OpenAIRE |
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