Ligand engagement of specific membrane receptors such as TNFR1, CD40, RANK, and TLR4 trigger the recruitment of specific adaptor proteins (TNF receptor 1-associated death domain protein (TRADD), MyD88, MAL, TIR domain-containing adaptor-inducing IFNβ (TRIF)), kinases (RIP1, IRAK1, IRAK4), and ubiquitin ligases (TRAF2, TRAF6, cIAP1, cIAP2) to the receptor.