Gabaldon, Toni;Huynen, Martijn - Evolution of the mitochondrial ancestor proteome

ECCB 2002 Poster sorted by: Author | Number

Next | Previous poster (in order of the view you have selected)

Title: Evolution of the mitochondrial ancestor proteome	P42
Gabaldon, Toni; Huynen, Martijn T.Gabaldon@cmbi.kun.nl CMBI, University of Nijmegen (The Netherlands)

Mitochondria play a central role in the energy metabolism of eukaryotic cells, not only many catabolic reactions but also the synthesis of important compounds take place inside this organell. Recently mitochondria have also been found to be involved in processes such as aging and apoptosis. The impairment of many of these pathways leads to severe degenerative diseases, mainly affecting the nervous and muscular systems. Leigh's and Leber's syndromes, Alzheimer, Friedrich's ataxia and Parkinson, are all examples of mitochondrial related diseases. Thus, a better understanding of the biochemical pathways in the mitochondria is of great importance. The study of the evolution of the mitochondrial proteome has also and intrinsic value for the understanding of the processes that lead to the transformation of an endosymbiont into a Eukaryotic organell. The mitochondrial ancestor arose from within a subdivision of the alpha-proteobacteria that contains the genus Rickettsia, an obligate intracellular parasite of eukaryotic cells. Since that event, the mitochondrial proteome -the subset of proteins that work in the mitochondria- has been re-shaped, adapting to its new function inside the Eukaryotic cell.

The availability of the complete genome sequences of some of the closest relatives of the mitochondria -Rickettsia prowazekii, Rickettsia conorii and other alphaproteobacteria- allow us to use comparative genomics to study the mitochondrial ancestor proteome and its evolution. Using phylogenetic analyses, we have developed an automated procedure to identify the alpha-proteobacterial proteins and their eukaryotic orthologs that are likely to be derived from the common ancestor of mitochondria and alpha-proteobacteria. The procedure involves the construction of the complete set of phylogenetic trees of the proteins encoded by the alpha-proteobacterial genomes, the so called "Phylome". By identifying eukaryotic proteins with an alpha-proteobacterial origin we obtain a minimal estimate of the mitochondrial ancestor proteome and how it evolved through the different eukaryotic lineages. By studying which proteins have coevolved with each other, we predict new pathways in the mitochondria and more specific interaction patterns between proteins in known pathways. A strong emphasis is devoted to disease-related pathways.

[1] B. Snel, P. Bork and M. A. Huynen. Genomes in flux: the evolution of archaeal and proteobacterial gene content. Genome Research 12, 17-25 (2002).
[2] J.H.P. Hackstein, A. Akhmanova, F. Voncken, A. van Hoek, T. Alen, B. Boxma, S. Y. Moon-van der Staay, G. Staay, J. Leunissen, M. A. Huynen, J. Rosenberg and M. Veenhuis. Hydrogenosomes: convergent adaptations of mitochondria to anaerobic environments. Zoology, 104, 290-302 (2001).
[3] M. A. Huynen, B. Snel, W. Lathe and P. Bork. "Predicting protein function by genomic context: quantitative evaluation and qualitative inferences'', Genome Research, 10, 1204-1210 (2000).
[4] M. A. Huynen, B. Snel, W. Lathe and P. Bork. ``Exploitation of gene context,'' Current Opinion in Structural Biology, 10, 366-370 (2000).