Chemokine (C-X-C motif) ligand 17 (CXCL17) is a smallcytokine initially thought to belong to the CXCchemokine family, then addressed as chemokine-like protein, that has been identified in humans and mice.
CXCL17 has been previously reported to attract dendritic cells and monocytes, but there are also studies not reporting this activity;[1] it is also regulated in tumors. It was formerly known asVEGF co-regulated chemokine 1 (VCC-1) anddendritic cell- and monocyte-attracting chemokine-like protein (DMC).[2][3] This chemokine is constitutively expressed in the respiratory tract and more specifically in the lung.[3] The gene for human CXCL17 is located onchromosome 19.[3] Human and murine CXCL17 protein share 71% of amino acid sequence identity.[4]
Doubt has been expressed that CXCL17 should truly be considered a member of the chemokine ligand family and it has therefore been described as a "Black Sheep".[5]
Being expressed in the respiratory tract mucosa, CXCL17 is likely to exert functions related to both immune surveillance of the tissue by fostering immune activation and immune suppression in case of overactivation of the immune system against harmless environmental antigens that can be commonly inhaled.CXCL17 also shows some anti-microbial activity against some bacteria, such as E.coli, S. aureus, Salmonella, P. aeruginosa and C. albicans strains.
The receptor for CXCL17 is aG protein-coupled receptor (GPCR). The GPCRGPR35 was thought to be a receptor of CXCL17[6] Subsequent research has suggested that GPR35 is not a receptor for CXCL17.[7][8] Indeed, recentlyGPR25 has been uniquely identified as CXCL17 receptor[1]
^Weinstein EJ, Head R, Griggs DW, Sun D, Evans RJ, Swearingen ML, Westlin MM, Mazzarella R (November 2006). "VCC-1, a novel chemokine, promotes tumor growth".Biochemical and Biophysical Research Communications.350 (1):74–81.Bibcode:2006BBRC..350...74W.doi:10.1016/j.bbrc.2006.08.194.PMID16989774.
