title: The chemokine CXC4 and CC2 receptors form homo- and heterooligomers that can engage their signaling G-protein effectors and βarrestin.
abstract: G-protein-coupled receptors have been shown to assemble at least as dimers early in the biosynthetic path, but some evidence suggests that they can also form larger oligomeric complexes. Using the human chemokine receptors CXCR4 and CCR2 as models, we directly probed the existence of higher order homo- and heterooligomers in human embryonic kidney cells. Combining bimolecular fluorescence and luminescence complementation (BiFC, BiLC) with bioluminescence resonance energy transfer (BRET) assays, we show that CXCR4 and CCR2 can assemble as homo- and heterooligomers, forming at least tetramers. Selective activation of CCR2 with the human monocyte chemotactic protein 1 (MCP-1) resulted in trans-conformational rearrangement of the CXCR4 dimer with an EC50 of 19.9 nM, compatible with a CCR2 action. Moreover, MCP-1 promoted the engagement of Gαi1, Gα13, Gαz, and βarrestin2 to the heterooligomer, resulting in calcium signaling that was synergistically potentiated on coactivation of CCR2 and CXCR4, demonstrating that complexes larger than dimers reach the cell surface as functional units. A mutation of CXCR4 (N119K), which prevents Gi activation, also affects the CCR2-promoted engagement of Gαi1 and βarrestin2 by the heterooligomer, supporting the occurrence of transprotomer regulation. Together, the results demonstrate that homo- and heteromultimeric CXCR4 and CCR2 can form functional signaling complexes that have unique properties.
authors: Department of Biochemistry, Institute for Research in Immunology and Cancer, and Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 5203, Institut National de la Santé et de la Recherche Médicale (INSERM) U661, University of Montpellier 1 and 2, Montpellier, France.
authors: Sylvain
authors: S
authors: Armando
authors: Department of Biochemistry, Institute for Research in Immunology and Cancer, and.
authors: Julie
authors: J
authors: Quoyer
authors: Department of Biochemistry, Institute for Research in Immunology and Cancer, and.
authors: Viktorya
authors: V
authors: Lukashova
authors: Department of Biochemistry, Institute for Research in Immunology and Cancer, and.
authors: Arhamatoulaye
authors: A
authors: Maiga
authors: Department of Biochemistry, Institute for Research in Immunology and Cancer, and.
authors: Yann
authors: Y
authors: Percherancier
authors: Department of Biochemistry, Research Centre/Hôpital Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada; and.
authors: Nikolaus
authors: N
authors: Heveker
authors: Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 5203, Institut National de la Santé et de la Recherche Médicale (INSERM) U661, University of Montpellier 1 and 2, Montpellier, France.
authors: Jean-Philippe
authors: JP
authors: Pin
authors: Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 5203, Institut National de la Santé et de la Recherche Médicale (INSERM) U661, University of Montpellier 1 and 2, Montpellier, France.
authors: Laurent
authors: L
authors: Prézeau
authors: Department of Biochemistry, Institute for Research in Immunology and Cancer, and michel.bouvier@umontreal.ca.
authors: Michel
authors: M
authors: Bouvier
mesh_terms: D019390:Arrestins / Q000378:metabolism*; D018932:Chemokine CCL2 / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D011485:Protein Binding; D055503:Protein Multimerization; D054390:Receptors, CCR2 / Q000378:metabolism*; D019718:Receptors, CXCR4 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; C111835:CCL2 protein, human; C515334:CCR2 protein, human; C527276:CXCR4 protein, human; D018932:Chemokine CCL2; D044385:GTP-Binding Protein alpha Subunits; D054390:Receptors, CCR2; D019718:Receptors, CXCR4; D000071557:beta-Arrestins
keywords: GPCR; allosteric regulation; complex formation; protein complementation assays; resonance energy transfer; transactivation