CCR9

The protein encoded by this gene is a G protein-coupled receptor with seven transmembrane domains that belongs to the beta chemokine receptor family. Chemokines and their receptors are key regulators of thymocyte migration and maturation in normal and inflammation conditions. This gene is differentially expressed in T lymphocytes of the small intestine and colon, and its interaction with chemokine 25 contributes to intestinal intra-epithelial lymphocyte homing to the small intestine. This suggests a role for this gene in directing immune responses to different segments of the gastrointestinal tract. This gene and its exclusive ligand, chemokine 25, are overexpressed in a variety of malignant tumors and are closely associated with tumor proliferation, apoptosis, invasion, migration and drug resistance. This gene maps to the chemokine receptor gene cluster. Multiple transcript variants encoding different isoforms have been found for this gene.