The TRAF (TNF receptor-associated factor) family is a group of adapter proteins (TRAFs 1-6) that link a wide variety of cell surface receptors to diverse signaling cascades leading to the activation of NF-kB and mitogen-activated protein kinases (reviewed in Chung et al, 2002). TRAFs are major signal transducers for both the TNF and IL- 1:TLR receptor superfamilies and collectively play important functions in both adaptive and innate immunity. The carboxy-terminal region of TRAFs is required for self-association and interaction with receptor cytoplasmic domains following ligand-induced oligomerization. TRAFs interact with a variety of proteins that regulate receptor-induced cell death or survival, and TRAF-mediated signaling can promote cell survival or interfere with death receptor-induced apoptosis. Human TRAF4 is a 470aa protein.