CD27 protein is a member of the TNF-receptor superfamily. It is required for generation and long-term maintenance of T cell immunity. This receptor binds to ligand CD70, and plays a crytical role in regulating B-cell activation and immunoglobulin synthesis. It transduces signals that lead to the activation of NF-kappaB and MAPK8/JNK. Adaptor proteins TRAF2 and TRAF5 have been shown to mediate the signaling process of this receptor. CD27-binding protein (SIVA), a proapoptotic protein, can bind to this receptor and is thought to play an important role in the apoptosis induced by this receptor.