Structural revelations of TRAF2 function in TNF receptor signaling pathway.

The tumor necrosis factor (TNF) receptor (TNFR) superfamily consists of over 20 type-I transmembrane proteins with conserved N-terminal cysteine-rich domains (CRDs) in the extracellular ligand binding region, which are specifically activated by the corresponding superfamily of TNF-like ligands. Members of this receptor superfamily have wide tissue distribution and play important roles in biological processes such as lymphoid and neuronal development, innate and adaptive immune response, and cellular homeostasis. A remarkable feature of the TNFR superfamily is the ability of these receptors to induce effects either for cell survival or apoptotic cell death. The downstream intracellular mediators of cell survival signal are a group of proteins known as TNFR associated factors (TRAFs). There are currently six canonical mammalian TRAFs. This review will focus on the unique structural features of TRAF2 protein and its role in cell survival signaling.