Pleiotropic regulation of mitochondrial translational factors in governing proliferation, apoptosis and metastasis during cancer progression

Figure 3 Schematic representation of mitochondrial translation. A-C: Initiation: The small mitochondrial ribosomal subunit (28S) associates with messenger RNA (mRNA) and initiator formylmethionyl-transfer RNA, facilitated by initiation factors mitochondrial initiation factor 2 and mitochondrial initiation factor 3 The large subunit (39S) then joins to form the complete 55S mitoribosome; D and E: Elongation: Aminoacyl-transfer RNAs are delivered to the ribosome by the elongation factor mitochondrial elongation factor Tu, and peptide bond formation occurs. Mitochondrial elongation factor Ts helps in the exchange of guanosine triphosphate with guanosine triphosphate for mitochondrial elongation factor Tu, and mitochondrial elongation factor G1 assists in the translocation step; F and G: Termination: Release factors (Mitochondrial release factor 1A) promote polypeptide chain release upon reaching a stop codon; H and I: Ribosome recycling: Ribosome recycling factors (mitochondrial ribosome recycling factor, mitochondrial elongation factor G2) facilitate dissociation of the ribosomal subunits and release of mRNA. Inset (left): The ribosome’s E, P, and A sites and the entry/exit channels for mRNA. Inset (bottom left): Legend of translation factors and cofactors involved in each step. fMET: Formylmethionyl; tRNA: Transfer RNA; mRNA: Messenger RNA; MTIF: Mitochondrial initiation factor; TUFM: Mitochondrial elongation factor Tu; TSFM: Mitochondrial elongation factor Ts; GFM1: Mitochondrial elongation factor G1; MTRF1 L: Mitochondrial release factor 1A; GFM2: Mitochondrial elongation factor G2; MRRF: Mitochondrial ribosome recycling factor; GTP: Guanosine triphosphate; GDP: Guanosine diphosphate. All cartoons in this figure were prepared using BioRender (Supplementary material).