The Translation Termination Factor eRF3 Interacts Sequentially with eRF1 and ABCE1 on the Ribosome

Abstract

To elucidate the molecular mechanisms connecting translation termination and ribosome recycling, interactions among eRF1, eRF3, and ABCE1, were genetically investigated in Saccharomyces cerevisiae. Heterologous factors from Pneumocystis carinii and humans, along with their mutants were successfully used for co-functional studies in conditional double knockout, double tetOFF strains. Combination of P. carinii eRF3 mutants with S. cerevisiae eRF1 and ABCE1 revealed that all the eRF3 mutants co-functioned with eRF1, but exhibited varying interactions with ABCE1 depending on the mutants. These findings provide evidence that eRF3 remains bound to the GTPase center of the ribosome, awaiting ABCE1. Thus, eRF3 sequentially interacts with eRF1 and ABCE1 during the final steps of translation.