The Immune receptor Translocation Associated genes/proteins consist of a five-member family of immunoglobulin-like cell surface receptors. The IRTAs were initially discovered by analysis of the breakpoints of a multiple myeloma cell line which contained a Iq21 chromosomal rearrangement. Each of the IRTA glycoproteins contains between 3 to 9 extracellular Ig-like domains. IRTAs are also characterized by having a cytoplasmic domain containing 3 to 5 tyrosine residues contained within particular motifs, suggesting the presence of immunotyrosine inhibitory motifs (ITIM) and immunotyrosine activation-like (ITAM-like) motifs.