Fig. 3. TIAM1 is cleaved by a caspase-3 family caspase in vitro. TIAM1 C1199 was in vitro transcribed and translated in the presence of [35S]methionine. The in vitro translated product was either left untreated (-) or incubated with extracts prepared from control Jurkat cells (0) or cells that had been stimulated with anti-Fas for 2 h (2). Extracts were prepared from wild-type Jurkat cells (WT) or I2.1, a Jurkat clone that is deficient in Fas-associated death domain. DEVD-CHO (100 nM) was added where indicated. Poly(ADP-ribose) polymerase, a defined caspase substrate, was used as a positive control. Reactions were resolved by SDS-PAGE and visualized by autoradiography. Arrow, TIAM1 cleavage peptide produced in vitro.