Cytotoxic And Regulatory T-Cell Molecule (CRTAM)

The deduced 393-amino acid human protein shares 72% amino acid identity with mouse Crtam. It contains a 17-amino acid leader sequence, followed by a 269-amino acid extracellular region, a 25-amino acid transmembrane domain, and an 82-amino acid cytoplasmic domain. The extracellular region has 5 potential N-glycosylation sites and 5 conserved cysteines, 4 of which appear to form 2 Ig-like domains. The cytoplasmic region has 3 conserved phosphorylation sites. Northern blot analysis detected high expression of 2.5- and 1.8-kb CRTAM transcripts in activated human CD8-positive cells, with lower levels in unactivated CD8-positive cells and CD4-positive cells. Among human tissues, CRTAM was abundantly expressed in spleen, thymus, small intestine, and peripheral blood leukocytes, with lower levels in testis, ovary, and colon.