Rat Fractalkine, FK ELI

Acts as a ligand for both CX3CR1 and integrins.

Binds to CX3CR1 and to integrins ITGAV:ITGB3 and ITGA4:ITGB1.

Can activate integrins in both a CX3CR1-dependent and CX3CR1-independent manner.

In the presence of CX3CR1, activates integrins by binding to the classical ligand-binding site (site 1) in integrins.

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.

The soluble form is chemotactic for T-cells and monocytes, but not for neutrophils.

The membrane-bound form promotes adhesion of those leukocytes to endothelial cells.

May play a role in regulating leukocyte adhesion and migration processes at the endothelium.