Chemokine receptor CXCR

Mohle R, Bautz F, Rafii S, Moore MA, Brugger W, Kanz L The chemokine receptor CXCR-4 is expressed on CD34+ hematopoietic progenitors and leukemic cells and mediates transendothelial migration induced by stromal cell-derived factor-1. Blood 1998 91 4523-4530. 

Venkatakrishnan G, SalgiaR, Groopman JE. Chemokine receptors CXCR-1/2 activate mitogen-activated protein kinase via the epidermal growth factor receptor in ovarian cancer cells. J Biol Chem 2000 275 6868-6875. 

A systematic nomenclature has been developed for the chemokine receptors (see Table 1). Thus, receptors for CC chemokines are referred to as CCR, receptors for CXC chemokines as CXCR, and the receptors for the XC and CX3C chemokines as XCR and CX3CR, respectively. To date, there are 10 CCRs (CCRs 1 to 10), 7 CXCRs, a single XCR, and a single CX3CR. The numbering is based on the date of deposition of the chemokine receptor sequence within the nucleic acid databases. For orphan receptors, this date refers to the point of identification of the orphan receptors as chemokine receptors and not to the date of initial deposition in the cDNA databases. 

Zamarchi R, Allavena P, Borsetti A, et al. Expression and functional activity of CXCR-4 and CCR-5 chemokine receptors in human thymocytes. Clin Exp Immunol... 

Milligan G, Wilson S, Lopez-Gimenez JF. The specificity and molecular basis of alphal-adrenoceptor and CXCR chemokine receptor dimerization. J Mol Neurosci 2005 26 161-168. 

Chemokine receptors are a family of G protein-coupled receptors that contain seven transmembrane domains. Chemokine receptors are present on the cell surface membrane of leukocytes. As was the case for chemokines, these receptors are also divided into four subgroups CCR is specific for CC chemokines, CXCR for CXC chemokines, XCR1 for C chemokines and CX3CR1 for CX3C chemokines. The CC chemokine receptor family has eleven members, the CXC chemokine receptor family has seven members, and both the C chemokine receptor family and the CX3C chemokine receptor family have one member each. The signal transduction is mediated via the standard G protein-dependent pathway. 

Cytokine and chemokine receptors An association between systemic sclerosis and polymorphisms in the CXCR-2 gene has been reported (Renzoni et al., 2000). 

Sehgal A., Keener C., Boynton A. L., et al. (1998) CXCR-4, a chemokine receptor, is overexpressed in and required for proliferationof glioblastoma tumor cells. J Surg Oncol., 69, 99-104. 

Ludwig A, Petersen F, Zahn S, et al. The CXC-chemokine neutrophU-activating peptide-2 induces two distinct optima of neutrophil chemotaxis by differential interaction with interleukin-8 receptors CXCR-1 and CXCR-2. Blood 1997 90 4588-4597. 

The chemokines are a family of small (8-12kDa) secreted chemoattractant cytokines that share a common structure dictated by the pattern of disulfide bonds that form between conserved cysteine (C) residues. The number and spacing of cysteines in the amino-terminus defines four chemokine classes, CXC, CC, XC and CX3C, where X represents any amino acid (aa) except C (Baggiolini and Loetscher 2000). A majority of chemokines have two sets of disulfide bonds formed by the pairing the first two cysteines (Ci and C2) with two others in a C1-C3 and C2-C4 pattern. These secreted proteins bind to G protein-coupled heptahelical receptors found on leukocytes that are designated by the class of chemokine bound (CXCRs, CCRs, XCRs, and CX3CR, respectively) (Rossi and Zlotnik 2000). 

Feil, C. and Augustin, H.G. (1998) Endothelial cells differentially express functional CXC-chemokine receptor-4 (CXCR-4/fusin) under the control of autocrine activity and exogenous cytokines. Biochemical and Biophysical Research Communications, 247, 38-45. 

ORF, open reading frame CXCR, CXC chemokine receptor CCR, CC chemokine receptor CPB, chemokine-binding protein. 

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