@article {Lagane1966, author = {Bernard Lagane and S{\'e}bastien Ballet and Thierry Planchenault and Karl Balabanian and Emmanuel Le Poul and C{\'e}dric Blanpain and Yann Percherancier and Isabelle Staropoli and Gilbert Vassart and Martin Oppermann and Marc Parmentier and Fran{\c c}oise Bachelerie}, title = {Mutation of the DRY Motif Reveals Different Structural Requirements for the CC Chemokine Receptor 5-Mediated Signaling and Receptor Endocytosis}, volume = {67}, number = {6}, pages = {1966--1976}, year = {2005}, doi = {10.1124/mol.104.009779}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {CC chemokine receptor 5 (CCR5) is a G protein-coupled receptor that governs migration of leukocytes and serves as a coreceptor for the R5 tropic strains of human immunodeficiency virus (HIV). CCR5-mediated signaling in response to CC chemokines relies on G protein activation. Desensitization, which rapidly turns off G protein-dependent signaling, involves phosphorylation of CCR5 that promotes interaction of the receptor with β-arrestins for endocytosis. Whether coupling to G proteins, desensitization, and endocytosis of CCR5 require the same structural determinants remains a matter of investigation. Here, we show that CCR5 displayed agonist-independent coupling to G proteins. This constitutive activity of the receptor was abrogated by TAK779 (N,N-dimethyl-N-[4-[[[2-(4-methylphenyl)-6,7-dihydro-5H-benzocyclohepten-8-yl]carbonyl]amino]benzyl]tetrahydro-2H-pyran-4-aminium chloride), a nonpeptidic CCR5 ligand that inhibits HIV infection and was found to depend on the integrity of the Asp-Arg-Tyr (DRY) motif. Changing Arg-126 by the neutral residue Asn (R126N-CCR5 mutant) abolished CCR5-mediated activation of G proteins, either constitutively or in response to agonists. In contrast, R126N-CCR5 not only retained agonist-promoted phosphorylation and β-arrestin-dependent endocytosis but also displayed a higher basal phosphorylation than wild-type CCR5. Expression of β-arrestin in R126N-CCR5-expressing cells resulted in receptor down-regulation, thereby suggesting that R126N-CCR5 spontaneously interacts with β-arrestins. However, although expression of β-arrestin favored wild-type CCR5-mediated chemotaxis, it failed to promote migration of cells expressing R126N-CCR5. Overall, these data indicate that structural requirements for CCR5-mediated activation of G proteins, albeit not involved in receptor desensitization and internalization, are needed for β-arrestin-mediated chemotaxis. These results have implications for how distinct biological responses of CCR5 might rely on a different set of receptor conformations.}, issn = {0026-895X}, URL = {https://molpharm.aspetjournals.org/content/67/6/1966}, eprint = {https://molpharm.aspetjournals.org/content/67/6/1966.full.pdf}, journal = {Molecular Pharmacology} }