CXC chemokine receptor type 6, member of the class A family of seven-transmembrane G protein-coupled receptors
CXCR6 binds specifically to the chemokine CXCL16, which is expressed on dendritic cells, monocyte/macrophages, activated T cells, fibroblastic reticular cells, and cancer cells. CXCR6 is phylogenetically more closely related to CC-type chemokine receptors (CCR6 and CCR9) than other CXC receptors. Chemokines are principal regulators for leukocyte trafficking, recruitment, and activation. Chemokine family membership is defined on the basis of sequence homology and on the presence of variations on a conserved cysteine motif, which allows the family to further divide into four subfamilies (CC, CXC, XC, and CX3C). Chemokines interact with seven-transmembrane receptors which are typically coupled to G protein for signaling. Currently, there are ten known receptors for CC chemokines, seven for CXC chemokines, and single receptors for the XC and CX3C chemokines.