CX3CR1

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

Function
Fractalkine is a transmembrane protein and chemokine involved in the adhesion and migration of is_associated_with::leukocytes. The protein encoded by this gene is a receptor for fractalkine.

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

Fractalkine has also recently been discovered to play a developmental role in the migration of is_associated_with::microglia in the is_associated_with::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 is_associated_with::AIDS.

CX3CR1 variants have been described to modify the survival time and the progression rate of patients with is_associated_with::amyotrophic lateral sclerosis.

Mutations in CX3CR1 are associated to dysplasia of the hip.