CX3CL1

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