Consequences of ChemR23 heteromerization with the chemokine receptors CXCR4 and CCR7

• Published in: PloS one Vol. 8; no. 2; p. e58075
• Main Authors: de Poorter, Cédric, Baertsoen, Kevin, Lannoy, Vincent, Parmentier, Marc, Springael, Jean-Yves
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28-02-2013; Public Library of Science (PLoS)
• Subjects: Adipocytes; Animals; Binding; Biology; Bone marrow; CC chemokine receptors; CCR2 protein; CCR5 protein; CCR7 protein; Cell Membrane - drug effects; Cell Membrane - metabolism; Chemokine receptors; Chemokines; CHO Cells; Cooperativity; Cricetinae; Cricetulus; CXCL12 protein; CXCR4 protein; Dendritic cells; Gene Expression Regulation - drug effects; Heterocyclic Compounds - pharmacology; Humans; Leukocytes; Ligands; Medicine; Metabolism; Mice; Monocyte chemoattractant protein 1; Penicillin; Phosphorylation; Protein Multimerization - drug effects; Protein Structure, Quaternary; Proteins; Receptors; Receptors, CCR7 - chemistry; Receptors, CCR7 - metabolism; Receptors, Chemokine - chemistry; Receptors, Chemokine - metabolism; Receptors, CXCR4 - antagonists & inhibitors; Receptors, CXCR4 - chemistry; Receptors, CXCR4 - metabolism; Substrate Specificity
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0058075

Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed.