Figure 7. PABP and eIF4B compete for binding to the eIF4G central region. In A and B, the amount of GST-eIF4G1100–1489, which contains the interaction domain for eIF4B and PABP, bound to glutathione Sepharose for each pull-down assay is shown in the Coomassie-stained gels (bottom panels). His-PABP1–393 was added to each reaction in a 1:1 molar ratio to GST-eIF4G1100–1489. (A) Full-length eIF4B (i.e., residues 1–527) or (B) His-eIF4B45–280 was added in increasing amounts to the binding reactions. The amount of PABP bound to GST-eIF4G1100–1489 was detected by Western analysis (top panels).