Chlamydomonas reinhardtii mitochondria as revealed by proteomics

Ariane Atteia1,2, Annie Adrait3, Sabine Brugière3, Robert van Lis1,2, Marianne Tardiff3, Jérôme Garin3, Jacques Joyard1 William Martin4 and Norbert Rolland1

1Laboratoire de Physiologie Cellulaire Végétale, CNRS (UMR5168)/Université Joseph Fourier/INRA (UM1200)/CEA, iRTSV CEA-Grenoble, 38054 Grenoble, France 2Unité de Bioénergétique et Ingénierie des Protéines, IBSM-CNRS, 31 Chemin J. Aiguier, 13 402 Marseille Cedex 20, France 3Laboratoire dÕEtude de la Dynamique des Protéomes, INSERM (U880)/CEA/Université Joseph Fourier, iRTSV CEA-Grenoble, 38054 Grenoble, France 4Institut of Botany, University of Düsseldorf, Germany

Mitochondria play a key role in the life, death, and energy of eukaryotic cells, but the full spectrum of mitochondrial functions is far from being completely understood, especially among photosynthetic organisms. An extensive proteomic analysis of Percoll-gradient purified mitochondria from mixotrophically grown Chlamydomonas reinhardtii was performed using denaturing or native gel electrophoresis and subsequent mass spectrometry. With the identification of 513 non-redundant proteins, this analysis represents a major step towards a (more) complete inventory of mitochondrial and mitochondria-associated proteins in the green alga. A variety of typical mitochondrial functions were identified including TCA cycle, oxidative phosphorylation, amino and fatty acid metabolisms. This mitochondrial proteome of C. reinhardtii however also revealed significant differences with mitochondrial proteomes of yeast, human and plants, such as the occurrence of a unique repertoire of bacterial-type fermentative enzymes and of photorespiratory enzymes including a glycolate dehydrogenase.

e-mail address of presenting author: Ariane.Atteia@ibsm.cnrs-mrs.fr