The function of CX3CL1 (C-X3-C motif chemokine ligand 1, ENSG00000006210) is as follows. Chemokine that acts as a ligand for both CX3CR1 and integrins ITGAV:ITGB3 and ITGA4:ITGB1 (PubMed:12055230, PubMed:21829356, PubMed:23125415, PubMed:9782118, PubMed:9931005). The CX3CR1-CX3CL1 signaling exerts distinct functions in different tissue compartments, such as immune response, inflammation, cell adhesion and chemotaxis (PubMed:12055230, PubMed:9024663, PubMed:9177350, PubMed:9782118). Regulates leukocyte adhesion and migration processes at the endothelium (PubMed:9024663, PubMed:9177350). Can activate integrins in both a CX3CR1-dependent and CX3CR1-independent manner (PubMed:23125415, PubMed:24789099). In the presence of CX3CR1, activates integrins by binding to the classical ligand-binding site (site 1) in integrins (PubMed:23125415, PubMed:24789099). In the absence of CX3CR1, binds to a second site (site 2) in integrins which is distinct from site 1 and enhances the binding of other integrin ligands to site 1 (PubMed:23125415, PubMed:24789099). {ECO:0000269|PubMed:12055230, ECO:0000269|PubMed:21829356, ECO:0000269|PubMed:23125415, ECO:0000269|PubMed:24789099, ECO:0000269|PubMed:9024663, ECO:0000269|PubMed:9177350, ECO:0000269|PubMed:9782118, ECO:0000269|PubMed:9931005}. [Processed fractalkine]: The soluble form is chemotactic for T-cells and monocytes, but not for neutrophils. . [Fractalkine]: The membrane-bound form promotes adhesion of those leukocytes to endothelial cells. . (Microbial infection) Mediates the cytoadherence of erythrocytes infected with parasite P.falciparum (strain 3D7) with endothelial cells by interacting with P.falciparum CBP1 and CBP2 expressed at the surface of erythrocytes (PubMed:27653778). The adhesion prevents the elimination of infected erythrocytes by the spleen (Probable). {ECO:0000269|PubMed:27653778, ECO:0000305|PubMed:27653778}.