Directs the termination of nascent peptide synthesis (translation) in response to the termination codons UAA, UAG and UGA (By similarity). Component of the transient SURF complex which recruits UPF1 to stalled ribosomes in the context of nonsense-mediated decay (NMD) of mRNAs containing premature stop codons.
Heterodimer of two subunits, one of which binds GTP. Component of the transient SURF (SMG1-UPF1-eRF1-eRF3) complex (By similarity). Interacts with Moloney murine leukemia virus (MoLV) reverse transcriptase/Ribonuclease H p80 (via RT and RNase domains); this interaction is essential for translational readthrough of amber codon between viral gag and pol genes. Interacts with MoLV Gag-Pol precursor.