CCL27, also known as CTACK (cutaneous T cell-attracting chemokine), ALP, ILC, and ESkine, is a member of the CC family of chemokines. Mature human CCL27 is an 88 amino acid (aa) protein that shares 57% aa sequence identity with mouse and rat CCL27. It shares 11% - 35% aa sequence identity with other human CC chemokines. An alternately spliced form of mouse CCL27, known as PESKY, is localized to the nucleus and promotes cellular migration. CCL27 is constitutively expressed by keratinocytes and is upregulated by inflammatory stimuli and in wounded skin. CCL27 binds the chemokine receptor CCR10, glycosaminoglycans in the extracellular matrix, sulfated tyrosine residues on PSGL-1, and determinants on the surface of fibroblasts and endothelial cells . CCL27 cooperates with CCL17/TARC in inducing the migration of cutaneous lymphocyte antigen (CLA) positive memory T cells to the skin during inflammation. Endothelial cell-bound CCL27 can mediate the adhesion of those cells to CLA+ T cells. CCL27 also induces the migration of keratinocyte precursors from bone marrow to the skin, thereby promoting wound healing. In humans, serum CCL27 levels are elevated and correlate with disease severity in atopic dermatitis, psoriasis vulgaris, and mycosis fungoides.
