Pab1 and eIF4G were known to interact with each other (Tarun and Sachs 1996; Tarun et al. 1997; Kessler and Sachs 1998). Furthermore, Sbp1 was shown to interact with eIF4G1, eIF4G2, and Pab1 in the cell in a proteomic investigation using open-reading frame tagging, affinity purification, and mass spectrometry (Gavin et al. 2002, 2006). It is conceivable that higher-order complexes can be formed on RNA by these proteins. Indeed, interactions between Sbp1, Pab1, and eIF4G1 on 5′UTRPab1 were observed (Fig. 4).