Regulation of TNFRSF and innate immune signalling complexes by TRAFs and cIAPs

There have been a number of recent discoveries relating to the functions of inhibitors of Apoptosis (IAPs) and TNF receptor-associated factors (TRAFs) in regulating signalling from TNF Receptor Superfamily (TNFRSF) members and some tantalizing glimpses into a wider area of influence, that of innate immune signalling. Discoveries relating to the function of these ubiquitin E3 Ligases in regulating signalling from the eponymous member of the family, TNF-R1, are dealt with superbly in a separate review by Wertz and Dixit and so we will confine our discussion to the subset of the TNFRSF that does not contain a death domain (DD). In line with the available data we will divide the review into two parts, the first is restricted to the role of TRAFs 2 and 3 and cIAPs in regulating TNFRSF signalling, whereas the second will be more speculative, asking what role IAPs and TRAFs have in innate immune signalling.