Translation initiation factor 3 (eIF3), the largest, most complex translation initiation factor, is involved in almost the entire process of translation initiation regulation, including ribosomal recruitment of the ternary complex, attachment of 43S complexes to mRNA via interaction with eIF4G, selection of the initiation codon (AUG), and prevention of premature association of the 40 and 60 S ribosomal subunits.