RIPK1 and colon carcinoma: RIP1 is ubiquitinated within the TNFR1-associated signaling complex-I, and RIP1 deubiquitination is reported to be necessary for the assembly of cytoplasmic complex-II.10, 33, 34 To investigate the ubiquitination status of RIP1 during necroptosis, human colon carcinoma HT29 cells were induced to undergo necroptosis with TNFα, IAP antagonist BV6 and the pancaspase inhibitor zVAD-fmk (combination hereafter referred as TBZ).