CD48 is a protein that in humans is encoded by CD48 gene. CD48 is a member of the CD2 subfamily of the immunoglobulin superfamily (IgSF) which includes SLAM (signaling lymphocyte activation molecules) proteins, such as CD84, CD150, CD229 and CD244. CD48 is found on the surface of lymphocytes and other immune cells, dendritic cells and endothelial cells, and participates in activation and differentiation pathways in these cells. The gene for CD48 is located in chromosome 1q23 and contains 4 exons, each exon encoding one of the 4 domains of CD48: signal peptide, variable (V) domain, constant 2 (C2) domain and the glycophosphatidylinositol anchor (GPI anchor). The cDNA sequence of 1137 nucleotides encodes a 243 amino acid polypeptide of about 45 kDa.