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The CC‐type chemokine receptor 1 (CCR1) is constitutively associated with βarrestin2: Role of receptor domains
Author(s) -
Gilliland Christian Taylor,
Salanga Catherina,
Trejo JoAnn,
Handel Tracy
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.972.7
Subject(s) - ccr1 , g protein coupled receptor , internalization , chemokine receptor , receptor , microbiology and biotechnology , chemistry , förster resonance energy transfer , arrestin , agonist , biophysics , biology , biochemistry , chemokine , fluorescence , quantum mechanics , physics
Careful regulation of the signaling activity of chemokine receptors is crucial to prevent inappropriate inflammatory responses, and arrestins play a key role in this process. The purpose of this study was to determine how arrestins associate with CCR1 and to identify the receptor's structural features that mediate this interaction. Using the bioluminescence resonance energy transfer (BRET) assay, it was observed that CCR1 is constitutively associated with βarrestin 2 and that this association is dependent upon a series of Ser/Thr residues in its distal C‐terminal tail. This ligand‐independent interaction was confirmed by co‐immunoprecipitation and fluorescence microscopy assays in endogenous and transient receptor expression systems. This can be explained by the observation that CCR1 is basally phosphorylated. Mutation of the Ser/Thr clusters inhibited receptor desensitization and internalization as well. Agonist binding to CCR1 was shown to primarily induce a conformational change in a pre‐formed CCR1/βarrestin 2 complex, as demonstrated in a BRET saturation assay. This represents the first report of ligand‐independent association of βarrestin 2 with CCR1 and could play an important role in developing CCR1 ligands that selectively modulate this interaction for therapeutic benefit. This work was supported by the NIH Pharmacological Sciences Training Grant and NIH grant R01AI037113‐14A1.