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. 2000 Dec 19;97(26):14376–14381. doi: 10.1073/pnas.97.26.14376

Figure 3.

Figure 3

IGFIR-IC-induced cell death is blocked by a catalytic mutant of pro-caspase-9. (A and B) 293T cells were transfected with 2 μg of DNA consisting of either pcDNA3, 0.5 μg pIGFR-IC + 1.5 μg pcDNA3, or 0.5 μg pIGFR-IC + 1.5 μg dominant negative caspase-9 (pC9DN, in A) or dominant negative caspase-7 (pC7DN, in B) expression constructs. Forty-eight hours after transfection, dead cells were counted. Asterisks denote a highly significant difference from the control as determined by one-way ANOVA. In A, F = 25.2, P = 0.0002 with P = 0.0001 for pIGFIR-IC (Bonferroni/Dunn posthoc test). In B, F = 118.487, P < 0.0001, with P < 0.0001 for pIGFIR-IC and pIGFIR-IC + pC7DN (Bonferroni/Dunn posthoc test). Error bars represent the SEM from three independent experiments. (C) Protein extracts from cells cotransfected with pIGFR-IC wild type or mutants, as indicated, and FLAG-tagged C9DN expression constructs were subjected to immunoprecipitation (IP) using an anti-IGFIR polyclonal antibody. Immunoprecipitates then were resolved by 15% SDS/PAGE, and Western blotting was performed by using a mAb against the FLAG epitope to detect caspase-9. WCE = whole-cell extract.