The plant mitochondrial protein import apparatus - the differences make it interesting.
BACKGROUND
Mitochondria play essential roles in the life and death of almost all eukaryotic cells, ranging from single-celled to multi-cellular organisms that display tissue and developmental differentiation. As mitochondria only arose once in evolution, much can be learned from studying single celled model systems such as yeast and applying this knowledge to other organisms. However, two billion years of evolution have also resulted in substantial divergence in mitochondrial function between eukaryotic organisms.


METHODS
Here we review our current understanding of the mechanisms of mitochondrial protein import between plants and yeast (Saccharomyces cerevisiae) and identify a high level of conservation for the essential subunits of plant mitochondrial import apparatus. Furthermore, we investigate examples whereby divergence and acquisition of functions have arisen and highlight the emerging examples of interactions between the import apparatus and components of the respiratory chain.


CONCLUSIONS
After more than three decades of research into the components and mechanisms of mitochondrial protein import of plants and yeast, the differences between these systems are examined. Specifically, expansions of the small gene families that encode the mitochondrial protein import apparatus in plants are detailed, and their essential role in seed viability is revealed.


CONCLUSIONS
These findings point to the essential role of the inner mitochondrial protein translocases in Arabidopsis, establishing their necessity for seed viability and the crucial role of mitochondrial biogenesis during germination. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
ARC Centre of Excellence in Plant Energy Biology, Bayliss Building M316, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia. Electronic address: monika.murcha@uwa.edu.au.
Monika W
MW
Murcha
ARC Centre of Excellence in Plant Energy Biology, Bayliss Building M316, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia.
Yan
Y
Wang
ARC Centre of Excellence in Plant Energy Biology, Bayliss Building M316, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia; Computational Systems Biology, Bayliss Building M316, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia.
Reena
R
Narsai
ARC Centre of Excellence in Plant Energy Biology, Bayliss Building M316, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia; Department of Botany, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia.
James
J
Whelan
D026901:Membrane Transport Proteins / Q000502:physiology*; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D010944:Plants / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins
Gene families; Mitochondrial biogenesis; Plant mitochondria; Protein import; TIM; TOM