Mitochondrial translational initiation factor 3 (MTIF3)

Mitochondrial translational initiation factor 3 (MTIF3) is a nuclear-encoded protein that is imported into mitochondria, where it plays a key role in the initiation phase of protein synthesis by binding to the small (28S) subunit of the mitochondrial ribosome. This action promotes the dissociation of mitochondrial 55S ribosomes into their 39S (large) and 28S (small) subunits, increasing the pool of available small subunits for translation initiation. MTIF3 is distinct from its bacterial counterpart in both structure and function, containing mitochondria-specific extensions and displaying different mechanisms in the assembly of the translation initiation complex. Loss of MTIF3 does not completely abolish mitochondrial translation but leads to defects such as selective reduction in the synthesis of certain proteins (e.g., ATP6), impairing the assembly of mitochondrial ATP synthase and mitochondrial energy production. Genetic variants in MTIF3 have been associated with combined oxidative phosphorylation deficiency and may play a role in neurodegenerative diseases, including Parkinson’s disease.

Other names

Translation initiation factor IF-3, mitochondrialIF3mtIF-3mtIF-3(Mt)DC38IF3(mt)IF3(Mt)