CTACK is a keratinocyte-derived CC chemokine which signals through the CCR10 receptor. Both CTACK and CCR10 are expressed in normal and irritated epithelial cells. CTACK selectively attracts CLA T-cells and directs them into the skin. CTACK contains the four highly conserved cysteine residues present in most CC chemokines. The mature protein contains 88 amino acid residues. Recombinant human CTACK is a 10.2 kDa protein containing 88 amino acid residues.