Tumor necrosis factor receptor II (TNFRII), also known as tumor necrosis factor receptor superfamily member 1B (TNFRSF1B), is a membrane receptor that binds tumor necrosis factor-alpha (TNF-α). This protein and TNF-receptor I form a heterocomplex that mediates the recruitment of two anti-apoptotic proteins, c-IAP1 and c-IAP2, which possess E3 ubiquitin ligase activity. The function of IAPs in TNF-receptor signalling is unknown, however, c-IAP1 is thought to potentiate TNF-induced apoptosis by the ubiquitination and degradation of TNF-receptor-associated factor 2 (TRAF2), which mediates anti-apoptotic signals. Knockout studies in mice also suggest a role of this protein in protecting neurons from apoptosis by stimulating antioxidative pathways.