Cxcl6

Chemokines, a subgroup of cytokines, are small (size between 8 and 10 kDa), chemotactically active proteins (signal proteins). They are common in all vertebrates, some virus types and bacteria. In humans, about 50 chemokines are currently known. A strongly conserved structural feature of all chemokines is a fixed group of cysteine residues that is stabilized by 1 or 2 disulfide bridges. This key structural position in the molecule is responsible for its fixed 3-dimensional structure (see below chemokines).

In the CC-chemokines the cysteines follow each other directly, in the CXC-chemokines they are separated by 1 (see figure), in the CXXXC-chemokines by 3 other amino acids. Chemokines are produced and secreted by a large number of immune cells. They mediate their signals by means of specific chemokine receptors via G-proteins.

The fact that chemokines and their receptors are not only expressed on inflammatory cells, but also by epithelial cells, mesenchymal cells, neurogenic cells, endothelial cells, and various tumor cell lines, suggests that they participate in numerous regulatory cell functions.

C-X-C motif chemokine 6 (CXCL6) is a protein of the CXC chemokine family. The coding CXCL6 gene is located on chromosome 4 in a gene cluster with genes from other CXC chemokines.

CXCL6 is produced by macrophages, epithelial and mesenchymal cells during an inflammatory reaction. By binding and activating its receptors (CXCR1 and CXCR2), this chemokine activates neutrophil granulocytes. Furthermore, it has angiogenetic effects and apparently has direct antibacterial effects. This has been shown for pathogenic Gram-positive and Gram-negative chemokines. CXCL6 is overexpressed together with other CXC chemokines(CXCL1,6,8) in rosacea papulopustulosa.

1. Wuyts A et al (1997) Characterization of synthetic human granulocyte chemotactic protein 2: usage of chemokine receptors CXCR1 and CXCR2 and in vivo inflammatory properties. Biochemistry 36:2716-2723.