Tumor necrosis factor Receptor II (TNF RII) is also known as tumor necrosis factor receptor superfamily member 1B (TNFRSF1B). This protein forms a heterogenic complex with TNF RI that mediates the recruitment of two anti-apoptotic proteins c-IAP1 and c-IAP2 with E3 ubiquitin ligase activity. The function of IAPs in TNF receptor signaling is unknown, however c-IAP1 is thought to enhance TNF induced apoptosis by ubiquitinating and degrading TNF receptor-associated factor 2 (TRAF2), which mediates anti-apoptotic signaling. Gene knockout experiments in mice have shown that the protein plays a role in protecting neurons from apoptosis by stimulating antioxidant pathways.