CX3CR1

CX3C chemokine receptor 1 (CX3CR1) also known as the fractalkine receptor or G-protein coupled receptor 13 (GPR13) is a protein that in humans is encoded by the CX3CR1 gene. As the name suggests, this receptor binds the chemokine CX3CL1 (also called neurotactin or fractalkine).

Function

The fractalkine ligand CX3CL1 is a transmembrane protein and chemokine involved in the adhesion and migration of leukocytes. The protein encoded by the CX3R1 gene is a receptor for the fractalkine ligand.

Expression of this receptor appears to be associated with lymphocytes. CX3CR1 is also expressed by monocytes and plays a major role in the survival of monocytes.

Fractalkine signalling has also recently been discovered to play a developmental role in the migration of microglia in the central nervous system to their synaptic targets, where phagocytosis and synaptic refinement occur. CX3CR1 knockout mice had more synapses on cortical neurons than wild-type mice.

Clinical significance

CX3CR1 also is a coreceptor for HIV-1, and some variations in this gene lead to increased susceptibility to HIV-1 infection and rapid progression to AIDS.