CX3CL1

Chemokine (C-X3-C motif) ligand 1
PDB rendering based on 1b2t.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1B2T, 1F2L, 3ONA, 4XT1, 4XT3
Identifiers
Symbols	CX3CL1 ; ABCD-3; C3Xkine; CXC3; CXC3C; NTN; NTT; SCYD1; fractalkine; neurotactin
External IDs	OMIM: 601880 MGI: 1097153 HomoloGene: 2251 GeneCards: CX3CL1 Gene
Gene ontology Molecular function • receptor binding • protein binding • chemokine activity • CCR chemokine receptor binding Cellular component • extracellular region • extracellular space • plasma membrane • cell surface • integral component of membrane • cell projection • perinuclear region of cytoplasm Biological process • response to hypoxia • microglial cell activation • positive regulation of neuroblast proliferation • monocyte chemotaxis • chemotaxis • defense response • immune response • cell adhesion • G-protein coupled receptor signaling pathway • aging • positive regulation of macrophage chemotaxis • cytokine-mediated signaling pathway • platelet activation • neutrophil chemotaxis • leukocyte chemotaxis • positive regulation of transforming growth factor beta1 production • positive regulation of GTPase activity • positive regulation of angiogenesis • negative regulation of vasoconstriction • eosinophil chemotaxis • macrophage chemotaxis • lymphocyte chemotaxis • positive regulation of smooth muscle cell proliferation • negative regulation of cytokine secretion • positive regulation of inflammatory response • leukocyte adhesive activation • positive regulation of calcium-independent cell-cell adhesion • angiogenesis involved in wound healing • inhibitory postsynaptic potential • chemokine-mediated signaling pathway • positive regulation of ERK1 and ERK2 cascade • cellular response to interferon-gamma • cellular response to interleukin-1 • cellular response to tumor necrosis factor • negative regulation of extrinsic apoptotic signaling pathway in absence of ligand Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	6376	20312
Ensembl	ENSG00000006210	ENSMUSG00000031778
UniProt	P78423	O35188
RefSeq (mRNA)	NM_001304392	NM_009142
RefSeq (protein)	NP_001291321	NP_033168
Location (UCSC)	Chr 16: 57.37 – 57.39 Mb	Chr 8: 94.77 – 94.78 Mb
PubMed search	[1]	[2]

Fractalkine also known as chemokine (C-X3-C motif) ligand 1 is a protein that in humans is encoded by the CX3CL1 gene.

Function

Fractalkine is a large cytokine protein of 373 amino acids, it contains multiple domains and is the only known member of the CX₃C chemokine family. It is also commonly known under the names fractalkine (in humans) and neurotactin (in mice). The polypeptide structure of CXC3L1 differs from the typical structure of other chemokines. For example, the spacing of the characteristic N-terminal cysteines differs; there are three amino acids separating the initial pair of cysteines in CX3CL1, with none in CC chemokines and only one intervening amino acid in CXC chemokines. CX3CL1 is produced as a long protein (with 373-amino acid in humans) with an extended mucin-like stalk and a chemokine domain on top. The mucin-like stalk permits it to bind to the surface of certain cells. However a soluble (90 kD) version of this chemokine has also been observed. Soluble CX3CL1 potently chemoattracts T cells and monocytes, while the cell-bound chemokine promotes strong adhesion of leukocytes to activated endothelial cells, where it is primarily expressed. CX3CL1 elicits its adhesive and migratory functions by interacting with the chemokine receptor CX3CR1. Its gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.

CX3CL1 is up-regulated in the hippocampus during a brief temporal window following spatial learning, the purpose of which may be to regulate glutamate-mediated neurotransmission tone. This indicates a possible role for the chemokine in the protective plasticity process of synaptic scaling.