FIG. 2.

Electrophoresis of radiolabeled CrmA and Serp2 proteins after incubation with ICE (caspase-1). ³⁵S-labeled CrmA and Serp2 proteins from transcription and translation in vitro were treated with ICE, and the products were resolved by electrophoresis on SDS or native (nondenaturing, nonreducing) 10% acrylamide gels and visualized by autoradiography. (A) SDS-polyacrylamide gel of CrmA incubated without ICE (lane 1), crmA with 50 U of ICE incubated for 15 min at 37°C (lane 2), Serp2 without ICE (lane 3), and Serp2 with ICE (lane 4). The positions of Kaleidoscope-prestained standards (Bio-Rad) are indicated to the left. (B) Native polyacrylamide minigel of CrmA without ICE (lane 1) or incubated with 50 U of ICE for 15 min (lane 2). The CrmA-ICE complex is indicated by the arrow. The positions of the Kaleidoscope markers are shown on the left: B, blue (myosin); M, magenta (β-galactosidase); G, green (bovine serum albumin); V, violet (carbonic anhydrase); and O, orange (soybean trypsin inhibitor). (C) Section of native polyacrylamide gel showing results of incubation of Serp2 with 50 U of ICE for various times at 37°C (lanes 1 to 4) or for 30 min at 37°C with various amounts of ICE (lanes 5 to 11) as shown above the lanes. Serp2 was left without ICE (lane 1) or was treated with 50 U of ICE for 30, 60, or 300 min (lanes 2 to 4, respectively). Serp2 was also incubated for 30 min with 0, 0.2, 1, 5, 25, 50, and 225 U of ICE (lanes 5 to 11, respectively). The position of the magenta (M) and green (G) Kaleidoscope markers are shown. (D) SDS gel of radiolabeled CrmA (lanes 1 to 4) and Serp2 (lanes 5 to 8) after treatment with ICE and/or the cross-linking agent EDC. Lanes: 1, untreated crmA; 2, EDC-treated (cross-linked) CrmA; 3, ICE-treated CrmA; 4, ICE- and EDC-treated CrmA; 5, untreated Serp2; 6, cross-linked Serp2; 7, ICE-treated Serp2; 8, ICE- and EDC-treated Serp2. The cross-linked ICE-CrmA complex in lane 4 is indicated by the arrow.