FIG. 4.
Treatment of recombinant Rac GTPases with recombinant caspases 3 and 8 in vitro. (A) Purified Rac1 (100 ng/μl) containing a His tag at the N terminus was incubated with caspase 3 (5 ng/μl) under the conditions described for Fig. 3. Upper panel, Western blot probed with a polyclonal antibody to Rac1 (C-11) against a C-terminal peptide of Rac1 (amino acids 177 to 184). Bottom panel, following stripping of the blot in the upper panel, it was reprobed with an anti-(His)6 antibody to detect the N-terminal fragments. (B) Western blot immunoassay of Rac1 incubated with recombinant caspase 8. (C and D) Cleavage patterns of recombinant His-tagged Rac2 incubated with caspase 3 or 8, respectively, under the conditions described for His-tagged Rac1 and analyzed with an anti-Rac2 (C-11) antibody.