Chemokine (C-X3-C motif) receptor 1 (CX3CR1) is an HIV coreceptor and also a leukocyte chemotactic/adhesion receptor for fractalkine, also known as neurotactin. CX3CR1 mediates chemotactic responses to the soluble form of fractalkine in neutrophils and T cells, and cytoadhesion to cells expressing membrane-anchored fractalkine, such as monocytes, T cells, and neutrophils. Cells transfected with CX3CR1 exhibited chemotaxis and transient increases in intracellular calcium concentration when exposed to fractalkine. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804