Figure 4.

TAK1 and caspase are reciprocally regulated. Recent evidence indicates that apoptosis and necroptosis are reciprocally regulated. Inhibition of caspase or deletion of c-FLIP induces necroptosis, whereas inhibition of TAK1 or RIPK3 induces apoptosis. We propose that the balance between apoptotic and necroptotic signals prevents cell death under normal conditions, and any event that causes imbalance between these reciprocal inhibitions, such as treatment with a caspase inhibitor, leads to cell death