TRAF-like <p> The tumour necrosis factor receptor (TNFR) associated factors (TRAFs) act as signal transducers for both TNFRs and interleukin-1/Toll-like receptors. TRAFs function in immunity, embryonic development, stress response and bone metabolism through their induction of cell proliferation, differentiation, and apoptosis [<cite idref="PUB00011818"/>]. TRAFs are characterised by two domains: an N-terminal domain containing RING and zinc finger motifs that is essential for the activation of downstream effectors, and a C-terminal TRAF domain that is essential for self-association and receptor interaction [<cite idref="PUB00011815"/>]. The TRAF-domain like fold is a beta-sandwich consisting of 8 strands in 2 beta sheets and has a circularly permuted greek-key immunoglobulin-fold topology that contains an extra strand.</p> <p> The substrate-binding domain (SBD) of the SIAH (seven in absentia homolog) family of proteins is structurally highly similar to the TRAF domain. The SIAH SBD interacts with a number of proteins, and is involved in TNF-alpha-mediated NFkappaB activation [<cite idref="PUB00011819"/>].</p>