Mitochondrial and plastid evolution in eukaryotes: an outsiders' perspective.
The eukaryotic organelles mitochondrion and plastid originated from eubacterial endosymbionts. Here we propose that, in both cases, prokaryote-to-organelle conversion was driven by the internalization of host-encoded factors progressing from the outer membrane of the endosymbionts towards the intermembrane space, inner membrane and finally the organelle interior. This was made possible by an outside-to-inside establishment in the endosymbionts of host-controlled protein-sorting components, which enabled the gradual integration of organelle functions into the nuclear genome. Such a convergent trajectory for mitochondrion and plastid establishment suggests a novel paradigm for organelle evolution that affects theories of eukaryogenesis.
Gross
Jeferson
J
Department of Biology, Roy J. Carver Center for Comparative Genomics, University of Iowa, 446 Biology Building, Iowa City, Iowa 52242, USA.
Bhattacharya
Debashish
D
D000818:Animals; D005057:Eukaryotic Cells / Q000502:physiology*; D019143:Evolution, Molecular; D006801:Humans; D010944:Plants; D018087:Plastids / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology