C-X-C chemokine receptor type 7 (CXCR-7) is a protein that in humans is encoded by the CXCR7gene.
This gene encodes a member of the G protein-coupled receptor family. This protein was earlier thought to be a receptor for vasoactive intestinal peptide (VIP) and was considered to be an orphan receptor. It is now classified as a chemokine receptor able to bind the chemokines CXCL12/SDF-1 and CXCL11. The protein is also a coreceptor for human immunodeficiency viruses (HIV). Translocations involving this gene and HMGA2 on chromosome 12 have been observed in lipomas. Alternatively spliced transcript variants encoding the same protein isoform have been found for this gene. Whereas some reports claim that the receptor induces signaling following ligand binding, recent findings in zebrafish suggest that CXCR7 functions primarily by sequestering the chemokine CXCL12.
However, another recent study has provided evidence that ligand binding to CXCR7 activates MAP kinases through Beta-arrestins, and thus has functions beyond ligand sequestration.
^Balabanian K, Lagane B, Infantino S, Chow KY, Harriague J, Moepps B, Arenzana-Seisdedos F, Thelen M, Bachelerie F (Oct 2005). "The chemokine SDF-1/CXCL12 binds to and signals through the orphan receptor RDC1 in T lymphocytes". J Biol Chem280 (42): 35760–6. doi:10.1074/jbc.M508234200. PMID16107333.
Libert F, Passage E, Parmentier M et al. (1992). "Chromosomal mapping of A1 and A2 adenosine receptors, VIP receptor, and a new subtype of serotonin receptor.". Genomics11 (1): 225–7. doi:10.1016/0888-7543(91)90125-X. PMID1662665.
Broberg K, Zhang M, Strömbeck B et al. (2003). "Fusion of RDC1 with HMGA2 in lipomas as the result of chromosome aberrations involving 2q35-37 and 12q13-15.". Int. J. Oncol.21 (2): 321–6. doi:10.3892/ijo.21.2.321. PMID12118328.
Hillier LW, Graves TA, Fulton RS et al. (2005). "Generation and annotation of the DNA sequences of human chromosomes 2 and 4.". Nature434 (7034): 724–31. doi:10.1038/nature03466. PMID15815621.
Infantino S, Moepps B, Thelen M (2006). "Expression and regulation of the orphan receptor RDC1 and its putative ligand in human dendritic and B cells.". J. Immunol.176 (4): 2197–207. doi:10.4049/jimmunol.176.4.2197. PMID16455976.
Proost P, Mortier A, Loos T et al. (2007). "Proteolytic processing of CXCL11 by CD13/aminopeptidase N impairs CXCR3 and CXCR7 binding and signaling and reduces lymphocyte and endothelial cell migration.". Blood110 (1): 37–44. doi:10.1182/blood-2006-10-049072. PMID17363734.
Wang J, Shiozawa Y, Wang J et al. (2008). "The role of CXCR7/RDC1 as a chemokine receptor for CXCL12/SDF-1 in prostate cancer.". J Biol Chem283 (7): 4283–4294. doi:10.1074/jbc.M707465200. PMID18057003.