TB2 is an alias for the gene, Receptor accessory protein 5, in humans. Other names include: Receptor expression-enhancing protein 5; Protein TB2; Polyposis locus protein 1; deleted in polyposis 1; polyposis coli region hypothetical protein DP1; C5orf18; D5S346; YOP1. The encoded protein has an amino acid length of 189 and a mass of 21.5 kDa. Other isoforms may exist. TB2 is a member of the DP1 family. This gene shares homology with other species, including: Mouse, Rat, Zebrafish, Frog, Chicken.