The function of MTIF3 (mitochondrial translational initiation factor 3, Ensembl gene identifier ENSG00000122033) is as follows. IF-3 binds to the 28S ribosomal subunit and shifts the equilibrium between 55S ribosomes and their 39S and 28S subunits in favor of the free subunits, thus enhancing the availability of 28S subunits on which protein synthesis initiation begins. .