Human Chemokine C-X-C-Motif Receptor 6 (CXCR6) Protein

Background

CXCR6 is a G protein-coupled receptor primarily expressed on T cells, natural killer T (NKT) cells, and some epithelial and endothelial cells. It binds its unique ligand CXCL16, which exists as both a soluble and membrane-bound form, facilitating cell adhesion and migration. CXCR6 plays a key role in T cell homing to inflamed tissues and tumor microenvironments, as well as in the maintenance of resident memory T cells. Inflammatory diseases such as rheumatoid arthritis, atherosclerosis, and liver fibrosis are associated with CXCR6-mediated immune cell recruitment. In cancer, CXCR6 expression is elevated in tumor-infiltrating lymphocytes and cancer cells, where CXCL16-CXCR6 signaling promotes cell adhesion, migration, and tumor progression. It has been implicated in prostate, breast, and lung cancers, enhancing metastasis to specific organs like the liver. CXCR6 also contributes to chronic viral infections, such as HIV and hepatitis, by directing immune cells to persistently infected tissues. Its signaling activates pathways like PI3K and MAPK, promoting cell survival and proliferation. CXCR6 is important for immune surveillance but, when dysregulated, supports chronic inflammation and disease progression, positioning it as a target for therapies in inflammation, cancer, and viral infections.