A heterodimeric protein that is a cell surface antigen associated with lymphocyte activation. The initial characterization of this protein revealed one identifiable heavy chain (FUSION REGULATORY PROTEIN 1, HEAVY CHAIN) and an indeterminate smaller light chain. It is now known that a variety of light chain subunits (FUSION REGULATORY PROTEIN 1, LIGHT CHAINS) can dimerize with the heavy chain. Depending upon its light chain composition a diverse array of functions can be found for this protein. Functions include: type L amino acid transport, type y+L amino acid transport and regulation of cellular fusion.

Synonyms: 4F2-antigen, Fusion Regulatory Protein-1, Human Lymphocyte Activation Antigen 4F2, Antigens, CD98, 4F2 Antigen, FRP-1 protein, H4F2 Antigen, Human 4F2 Antigen, Regulatory Protein-1, Fusion, CD98 Antigens, FRP 1 protein, 0, Transport Proteins, CD98, Fusion Regulatory Protein 1, Human 4F2 Cell-Surface Antigen, Antigen 4F2, 4F2 Antigen, Human, Antigen, CD98, Human 4F2 Cell Surface Antigen, CD98 Antigen, CD98 Transport Proteins