CD98, also known as 4F2, FRP-1, or RL-388, is the heavy subunit of the cell-surface protein complex that induces the uptake of dibasic and neutral amino acids. CD98 heavy chain (CD98hc) is an 80-85 kDa, type II membrane glycoprotein that is disulfide-linked to one of several non-glycosylated 40-45 kDa light chains (LAT1, the integrin a 3 subunit, or one of several members of the glycoprotein-associat ed amino acid transporter family). The CD98 complex is a multi-functional protein that plays a role in the regulation of virus-mediated cell fusion, oncogenesis, amino acid transport, integrin regulation, and Na + -Ca 2+ exchange. It is widely expressed on the surface of activated lymphocytes and various tumor cells.Synonyms: 4F2 cell-surface antigen heavy chain, 4F2 heavy chain antigen, 4F2hc, Lymphocyte activation antigen 4F2 large subunit, MDU1