Evolution of the molecular machines for protein import into mitochondria.
In creating mitochondria some 2 billion years ago, the first eukaryotes needed to establish protein import machinery in the membranes of what was a bacterial endosymbiont. Some of the preexisting protein translocation apparatus of the endosymbiont appears to have been commandeered, including molecular chaperones, the signal peptidase, and some components of the protein-targeting machinery. However, the protein translocases that drive protein import into mitochondria have no obvious counterparts in bacteria, making it likely that these machines were created de novo. The presence of similar translocase subunits in all eukaryotic genomes sequenced to date suggests that all eukaryotes can be considered descendants of a single ancestor species that carried an ancestral "protomitochondria."
Dolezal
Pavel
P
Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville 3010, Australia.
Likic
Vladimir
V
Tachezy
Jan
J
Lithgow
Trevor
T
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D005057:Eukaryotic Cells / Q000378:metabolism; D019143:Evolution, Molecular; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism; D021381:Protein Transport; D012697:Serine Endopeptidases / Q000378:metabolism; D013559:Symbiosis
D001426:Bacterial Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; D012697:Serine Endopeptidases; C026515:type I signal peptidase