Figure 5.

TGFβ-mediated caspase-8 activation is FADD-independent. (A) Independent clones of BL41 cells producing either endogenous FADD only or various amounts of the truncated form of FADD were cultured for 48 h without (−) or with TGFβ (1 ng/ml). Shrunken cells were counted by flow cytometry, as described in Figure 1. The production of FADD and FADD-DN was assessed by immunoblotting of the cell lysates obtained from each of the unstimulated clones. (B) After 48 h of incubation with or without TGFβ, the cleavage of caspase-8 was determined by immunoblotting the cell lysates obtained from clones 7 and 4. The blot was reprobed with anti-FADD antibodies to determine FADD and FADD-DN levels.