CCR9

C-C chemokine receptor type 9 is a protein that in humans is encoded by the CCR9 gene.

CCR9 has also recently been designated CDw199 (cluster of differentiation w199).

The protein encoded by this gene is a member of the beta chemokine receptor family. It is predicted to be a seven transmembrane protein similar to G protein-coupled receptors. Chemokines and their receptors are key regulators of thymocyte migration and maturation in normal and inflammatory conditions. The specific ligand of this receptor is CCL25. It has been found that this gene is differentially expressed by T lymphocytes of small intestine and colon, suggested a role in thymocyte recruitment and development that may permit functional specialization of immune responses in different segments of the gastrointestinal tract. This gene is mapped to the chemokine receptor gene cluster region. Two alternatively spliced transcript variants have been described.