Fig 3.

bVAD-fmk trapping of activated initiator caspase-8. (A) TRAIL-sensitive U343MG cells and TRAIL-resistant LN443 cells were pre-treated with bVAD-fmk for 2 hrs and stimulated with 300 ng/ml TRAIL for the times indicated above the panel. The cells were lysed and subjected to Western blotting for cleavage of caspase-8 (Casp-8) and caspase-3 (Casp-3). (B) U343MG and LN443 cells were treated with bVAD-fmk and then TRAIL- and bVAD-fmk-trapped activated caspases were pulled down by streptavidin and examined by Western blotting, with acetyl-CoA carboxylase as a control for precipitation and loading.