Translation initiation regulator which represses non-AUG initiated translation and repeat-associated non-AUG (RAN) initiated translation by acting as a competitive inhibitor of eukaryotic translation initiation factor 5 (EIF5) function (PubMed:21745818, PubMed:28981728, PubMed:34260931, PubMed:29470543). Increases the accuracy of translation initiation by impeding EIF5-dependent translation from non-AUG codons by competing with it for interaction with EIF2S2 within the 43S pre-initiation complex (PIC) in an EIF3C-binding dependent manner (PubMed:21745818, PubMed:28981728, PubMed:34260931). Interacts with EIF3E (PubMed:21745818). Interacts with EIF2S2 (PubMed:21745818, PubMed:25147208, PubMed:34260931). Interacts with EIF3C (PubMed:34260931). Belongs to the BZW family. Contaminating sequence. Potential poly-A sequence.