CXCR3
Description
The CXCR3 (C-X-C motif chemokine receptor 3) is a protein-coding gene located on chromosome X.
CXCR3 is a Gαi protein-coupled receptor in the CXC chemokine receptor family. Other names for CXCR3 are G protein-coupled receptor 9 (GPR9) and CD183. There are three isoforms of CXCR3 in humans: CXCR3-A, CXCR3-B, and chemokine receptor 3-alternative (CXCR3-alt). CXCR3-A binds to the CXC chemokines CXCL9 (MIG), CXCL10 (IP-10), and CXCL11 (I-TAC), whereas CXCR3-B can also bind to CXCL4 in addition to CXCL9, CXCL10, and CXCL11. CXCR3 is expressed primarily on activated T lymphocytes and NK cells, and some epithelial cells. CXCR3 and CCR5 are preferentially expressed on Th1 cells, whereas Th2 cells favor the expression of CCR3 and CCR4. CXCR3 ligands that attract Th1 cells can concomitantly block the migration of Th2 cells in response to CCR3 ligands, thus enhancing the polarization of effector T cell recruitment. Binding of CXCL9, CXCL10, and CXCL11 to CXCR3 is able to elicit increases in intracellular Ca2++ levels and activate phosphoinositide 3-kinase and mitogen-activated protein kinase (MAPK). Detailed signaling pathway has not yet been established, but may include the same enzymes that were identified in the signaling cascade induced by other chemokine receptors. CXCR3 is able to regulate leukocyte trafficking.
CXCR3 is also known as CD182, CD183, CKR-L2, CMKAR3, GPR9, IP10-R, Mig-R, MigR.
