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 (By similarity). 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 (By similarity). Interacts with EIF3E, EIF2S2 and EIF3C. Belongs to the BZW family.