FIGURE 8.

Phosphorylated eIF3h is likely the activated isoform of eIF3h. A, cell extracts of 3T3/pcDNA5, 3T3/eIF3h(S183A), 3T3/eIF3h, 3T3/eIF3h(S183D), and 3T3/eIF3h(S183E) cells were analyzed by immunoblots probed with anti-eIF3h and anti-actin antibodies. Relative eIF3h band intensities are shown below the blots. B, 3T3 cells as in A were lysed and subjected to immunoprecipitation (IP) with anti-HA resin as described under “Experimental Procedures.” The immunoprecipitations were analyzed by SDS-PAGE and immunoblotting with antiserum specific for eIF3a, eIF3b, and eIF3c. C, growth curves of the indicated cell lines, determined as described in the legend to Fig. 3B. D, colonies formed in soft agar with the same cell lines. Colony forming units (CFU) measured as described in the legend to Fig. 3D are shown below. E, indicated cell lines were transfected with a vector expressing Myc; 48 h post-infection the cells were treated with the indicated concentrations of camptothecin for 24 h. Cell viability was measured as described in Ref. 7. F, immunoblot analysis with anti-PARP after treatment of the Myc-transfected cells with 1.5 μm camptothecin for 24 h. The relative PARP levels are shown below the blots. The results shown above are a representative of three independent experiments.