How does il-1 differ from tnf in activating cells?
From the above descriptions of IL-1R and IL-1 signal transduction, many of these pathways are shared with TNF. Although the receptors for TNF and IL-1 are clearly different, the postreceptor events are amazingly similar. Thus, the finding that IL-1 and TNF activate the same portfolio of genes is not surprising; however, given the same cell and given the same array of activated genes, IL-1 does not result in programmed cell death, whereas TNF does. This can be seen in TNF responsive fibroblast in which IL-1 and TNF induce IL-8 but in the presence of actinomycin C or cycloheximide, TNF induces classical apoptosis but IL-1 does not. IL-1 will often synergize with TNF for NO induction and under those conditions, NO mediates cell death. The best example of this can be found in the insulin-producing cells in the islets of Langerhans in the pancreas (Reimers et al, 1994). Unlike IL-1, the receptors for TNF are homodimers and trimers and hence the recruitment of kinases is somewhat different;
