FIG. 2. DR5 and c-FLIPL interact in vitro.
A, interaction of a c-FLIP peptide with DR5 protein. We displayed on the phage a c-FLIP peptide segment resembling the sequence of the peptide ligand selected by the DD of DR5 from a phage-displayed combinatorial peptide library. In this format, the c-FLIP peptide specifically interacts with GST-DR5 protein, but not to unrelated GST fusion proteins, in an ELISA. B, interaction of full-length c-FLIPL with DR5 in a GST pull-down assay. Cell lysates were prepared from HEK 293 cells ectopically expressing FLAG-tagged c-FLIPL or FLAG-tagged c-FLIPp12. These cell lysates were used in a GST pull-down assay with GST fusion proteins of DR5 and immunoblotted with an anti-FLAG antibody. Total cell lysate is used as a control to monitor expression of c-FLIPL and c-FLIPp12.