Importantly, addition of RNase disrupts the Sbp1–Pab1 as well as Sbp1–Pab1–eIF4G1 interactions on 5′UTRPab1 (Figs. 3A, 4), but leaves Sbp1RGG–Pab1 and Pab1–eIF4G1 interactions unchanged (Figs. 3B, 4). These results confirm that the exposure and conformation of the RGG domain in Sbp1 by RNA binding is important for the protein–protein interaction, which explains why the interaction between Sbp1–Pab1 is RNA-dependent. Furthermore, we noticed that the RGG repeats in Sbp1 are located in between the two RRM domains, much unlike many other RGG-motif proteins which contain the RGG repeats in the terminal regions (data not shown). This domain organization of Sbp1 would likely remodel the RNA structure that it binds by positioning of the central RGG repeats for protein interactions in an RNA-dependent manner.