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. Expressed at high levels in heart, and at lower levels in skeletal muscle, spleen and lung. Expressed at low levels in brain regions where nascent and immature neurons are present. Expressed at E8. In brain, expression increases between E14 and E16, reaches a plateau at E18, and subsequently decreases. Belongs to the BZW family.