PVR is a member of Ig-superfamily with 3 Ig-domains in arrangement V-C-C. Four mRNAs are produced from single gene for PVR, (mapped to human chromosome band 19q13.1-13.2). Two of the mRNAs (called H20A and H20B or α and δ,) encode cell surface molecules of about 43kDa and 45kDa polypeptide backbone, respectively. Two other splice variants, β and γ and encode secreted molecules of about 44kDa. The cytoplasmic tails are short (aa 35-50) and are rich in serine phosphorylated residues.