[en] The Alternative oxidase (AOX) is an ubiquinol-oxygen oxidoreductase found in the mitochondrial inner membrane of plants, fungi and protists. In mitochondria, AOX activation creates an electron partitioning between the cytochrome pathway (CIII + CIV) and AOX. This partitioning leads to a decrease of proton pumping efficiency by the respiratory chain complexes per O2 consumed. Two closely related physiological roles are attributed to AOX: First, AOX in conjunction with rotenone insensitive NADH dehydrogenases, generates a fully non-coupled (energy dissipative) electron transport chain in the mitochondria, which is believed to play an important role in regenerating oxidized cofactors required for others metabolic demands. The second proposed role of AOX is to prevent an important increase the QR/Qt ratio and consequently, to prevent reactive oxygen species (ROS) production. In Chlamydomonas reinhartii AOX is encoded by two different genes, the AOX1 gene being much more transcribed than AOX2. In addition, the expression of the AOX1 gene is generally unresponsive to a number of known AOX allosteric effectors, but is down-regulated by ammonium and up-regulated by nitrate. In the present work, we performed a comparative proteomic study of isolated mitochondria by using the 2D-DIGE methodology to evidence the effects of AOX1 silencing on Chlamydomonas mitochondrial soluble proteome cultivated on nitrate in myxotrophic conditions
