cd04089

eRF3_II: domain II of the eukaryotic class II release factor (eRF3). In eukaryotes, translation termination is mediated by two interacting release factors, eRF1 and eRF3, which act as class I and II factors, respectively. eRF1 functions as an omnipotent release factor, decoding all three stop codons and triggering the release of the nascent peptide catalyzed by the ribsome. eRF3 is a GTPase, which enhances the termination efficiency by stimulating the eRF1 activity in a GTP-dependent manner. Sequence comparison of class II release factors with elongation factors shows that eRF3 is more similar to eEF1alpha whereas prokaryote RF3 is more similar to EF-G, implying that their precise function may differ. Only eukaryote RF3s are found in this group. Saccharomyces cerevisiae eRF3 (Sup35p) is a translation termination factor which is divided into three regions N, M and a C-terminal eEF1a-like region essential for translation termination. Sup35NM is a non-pathogenic prion-like protein with the property of aggregating into polymer-like fibrils.