Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8298942 | Biochimica et Biophysica Acta (BBA) - Bioenergetics | 2010 | 10 Pages |
Abstract
Nitrate and ammonium constitute primary inorganic nitrogen sources that can be incorporated into carbon skeletons in photosynthetic eukaryotes. In Chlamydomonas, previous studies and the present one showed that the mitochondrial AOX is up-regulated in nitrate-grown cells in comparison with ammonium-grown cells. In this work, we have performed a comparative proteomic analysis of the soluble mitochondrial proteome of Chlamydomonas cells growth either on nitrate or ammonium. Our results highlight important proteomics modifications mostly related to primary metabolism in cells grown on nitrate. We could note an up-regulation of some TCA cycle enzymes and a down-regulation of cytochrome c1 together with an up-regulation of l-arginine and purine catabolism enzymes and of ROS scavenging systems. Hence, in nitrate-grown cells, AOX may play a dual role: (1) lowering the ubiquinone pool reduction level and (2) permitting the export of mitochondrial reducing power under the form of malate for nitrate and nitrite reduction. This role of AOX in the mitochondrial plasticity makes logical the localization of Aox1 in a nitrate assimilation gene cluster.
Keywords
NIRP450norHRGPGOGATIDHCOARNSGDHAOXHCP2D-DIGEROSMetabolic flexibilityAlternative oxidaseIsocitrate dehydrogenaseBioenergeticsNitrogen sourceMitochondrianitrate reductasenitrite reductaseComparative proteomicsTCA cycletricarboxylic acid cyclecoenzyme Aglutathione reductaseglutathione peroxidaseglutamate dehydrogenaseGlutamine synthasehydroxyproline-rich glycoproteinreactive nitrogen speciesReactive oxygen species
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Authors
Stéphanie Gérin, Grégory Mathy, Arnaud Blomme, Fabrice Franck, Francis E. Sluse,