CD253 (TRAIL; TNF-Related Apoptosis Inducing Ligand or Apo2) is a type II membrane protein from the TNF family. TRAIL is a cytotoxic protein which activates rapid apoptosis in tumor cells, but not in normal cells. TRAIL-induced apotosis, is achieved through binding to two dealth-signaling receptors, DR4 (CD261 / TRAIL-R1) and DR5 (CD262 / TRAIL-R2).