CX3C chemokines

Combadiere C, Salzwedel K, Smith ED et al (1998b) Identification of CX3CR1. A chemotactic receptor for the human CX3C chemokine fractaUdne and a fusion coreceptor for HlV-1. J Biol Chem 273 23799-23804... 

Chen S, Bacon KB, Li L, et al. In vivo inhibition of CC and CX3C chemokine-induced leukocyte infiltration and attenuation of glomerulonephritis in Wistar-Kyoto (WKY) rats by vMIP-II. J Exp Med 1998 188 193-8. 

Mizoue LS, Bazan JF, Johnson EC, Handel TM. Solution structure and dynamics of the CX3C chemokine domain of fractalkine and its interaction with an N-terminal fragment of CX3CR1. Biochemistry 1999 38 1402-14. 

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. 

Combadiere C, Gao J, Tiffany HL, Murphy PM. Gene cloning, RNA distribution, and functional expression of mCX3CRl, a mouse chemotactic receptor for the CX3C chemokine fractalkine. Biochem Biophys Res Commun 1998 253(3) 728-732. 

Lucas AD, Bursill C, Guzik TJ, Sadowski J, Channon KM, Greaves DR. Smooth muscle cells in human atherosclerotic plaques express the fractalkine receptor CX3CR1 and undergo chemotaxis to the CX3C chemokine fractalkine (CX3CL1). Circulation 2003 108(20) 2498-2504. 

Umehara H, Goda S, finai T, et al. Fractalkine, a CX3C-chemokine, functions predominantly as an adhesion molecule in monocytic cell line THP-1. Immunol Cell Biol 2001 79(3) 298-302. 

Rimaniol AC, Till SJ, Garcia G, et al. The CX3C chemokine fractalkine in allergic asthma and rhinitis. J Allergy Clin Immunol 2003 112(6) 1139—1146. 

Also termed 8-chemokines, CX3C Chemokines are composed of three amino acids between the two cysteines. This subgroup has only one member, fractalkine (CX3CL1). CX3C chemokines are secreted as well as present on the cell surface and serve both as a chemoattractant and as an adhesion molecule. 

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. 

Mizoue LS, Sullivan SK, King DS, Kledal TN, Schwartz TW, Bacon KB, Handel TM (2001) Molecular determinants of receptor binding and signaling by the CX3C chemokine fractalkine. J Biol Chem 276 33906-33914. 

Chemokine family. The mediators are divided into four subclasses according to chemical characteristics of the ligands, namely the number or positions of cyteine residues, as follows CC chemokines CXC chemokines CX3C chemokine C chemokines. These chemokines act at receptors largely named after the peptides themselves, and include CCCRl-8 and CXRl-4. (Chemokines recognized include MIP-la MIP-ip MCP-1 MCP-2 MCP-3 MCP-4 MIP-5 RANTES LCRl leukotactin-1 eotaxin, eotaxin-1 and some other chemokines. 

Human fractalkine is the only CX3C chemokine identified to date, and is unique beeause there are three amino acids between the first two cysteines and... 

Kledal, T. N., Rosenkilde, M. M., and Schwartz, T. W. (1998). Selective recognition of the membrane-bound CX3C chemokine, fractalkine, by the human cytomegalovirus-encoded broad-spectrum receptor US28. FEBS Lett. 441, 209-214. 

Chemokines are a family of pro-inflammatory activation-inducible cytokines or small protein signals secreted by cells. Chemokines induce directed chemotaxis in nearby responsive cells and therefore the name c/iemotactic cytokines. Four types of chemokines exist (1) C chemokine the first and the third conserved cysteine residues in the mature protein are missing (2) CC chemokine the first two conserved cysteine residues are adjacent in the mature protein (3) CXC chemokine one amino acid residue separates the first two conserved cysteine residues in the mature protein and (4) CX3C chemokine three amino acid residues separate the first two conserved cysteine residues in the mature protein. 

Goda, S., Imai, T., Yoshie, O., Yoneda, O., Inoue, H., Nagano, Y, Okazaki, T., Imai, H., Bloom, E. T., Domae, N., and Umehara, H. (2000). CX3C-chemokine, fractalkine-enhanced adhesion of THP-1 cells to endothelial cells through integrin-dependent and -independent mechanisms. J. Immunol. 164, 4313-4320. 

WUhanks A, Zondlo SC, Murphy K, et al. Expression cloning of the STRL33/ BONZO/TYMSTR ligand reveals elements of CC, CXC, and CX3C chemokines. J Immunol 2001 166 5145-5154. 

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