Mitochondrial translation initiation machinery: conservation and diversification

Biochimie. 2014 May;100(100):132-40. doi: 10.1016/j.biochi.2013.07.024. Epub 2013 Aug 14.


The highly streamlined mitochondrial genome encodes almost exclusively a handful of transmembrane components of the respiratory chain complex. In order to ensure the correct assembly of the respiratory chain, the products of these genes must be produced in the correct stoichiometry and inserted into the membrane, posing a unique challenge to the mitochondrial translational system. In this review we describe the proteins orchestrating mitochondrial translation initiation: bacterial-like general initiation factors mIF2 and mIF3, as well as mitochondria-specific components - mRNA-specific translational activators and mRNA-nonspecific accessory initiation factors. We consider how the fast rate of evolution in these organelles has not only created a system that is divergent from that of its bacterial ancestors, but has led to a huge diversity in lineage specific mechanistic features of mitochondrial translation initiation among eukaryotes.

Keywords: IF2; IF3; Mitochondria; Ribosome; Translational activators.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Biological Evolution
  • Electron Transport / genetics
  • Humans
  • Mitochondria / genetics*
  • Mitochondria / metabolism
  • Mitochondrial Proteins / genetics*
  • Mitochondrial Proteins / metabolism
  • Molecular Sequence Data
  • Peptide Chain Initiation, Translational*
  • Prokaryotic Initiation Factor-2 / genetics
  • Prokaryotic Initiation Factor-2 / metabolism
  • Prokaryotic Initiation Factor-3 / genetics
  • Prokaryotic Initiation Factor-3 / metabolism
  • Pseudomonas / genetics
  • Pseudomonas / metabolism
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Ribosomes / genetics
  • Ribosomes / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Sequence Homology, Amino Acid


  • Mitochondrial Proteins
  • Prokaryotic Initiation Factor-2
  • Prokaryotic Initiation Factor-3
  • RNA, Messenger