New thioredoxin targets in the unicellular photosynthetic eukaryote Chlamydomonas reinhardtii.
Proteomics were used to identify the proteins from the eukaryotic unicellular green alga Chlamydomonas reinhardtii that can be reduced by thioredoxin. These proteins were retained specifically on a thioredoxin affinity column made of a monocysteinic thioredoxin mutant able to form mixed disulfides with its targets. Of a total of 55 identified targets, 29 had been found previously in higher plants or Synechocystis, but 26 were new targets. Biochemical tests were performed on three of them, showing a thioredoxin-dependent activation of isocitrate lyase and isopropylmalate dehydrogenase and a thioredoxin-dependent deactivation of catalase that is redox insensitive in Arabidopsis. In addition, we identified a Ran protein, a previously uncharacterized nuclear target in a photosynthetic organism. The metabolic and evolutionary implications of these findings are discussed.
Lemaire
Stéphane D
SD
Institut de Biotechnologie des Plantes, Bâtiment 630, Unité Mixte de Recherche 8618, Centre National de la Recherche Scientifique/Université Paris-Sud, F-91405 Orsay-Cedex, France. lemaire@ibp.u-psud.fr
Guillon
Blanche
B
Le Maréchal
Pierre
P
Keryer
Eliane
E
Miginiac-Maslow
Myroslawa
M
Decottignies
Paulette
P
D000085:Acetates / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000596:Amino Acids / Q000096:biosynthesis; D000818:Animals; D002244:Carbon / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D002846:Chromatography, Affinity; D002952:Citric Acid Cycle; D015180:Electrophoresis, Gel, Two-Dimensional; D005227:Fatty Acids / Q000096:biosynthesis; D009584:Nitrogen / Q000378:metabolism; D018384:Oxidative Stress; D010788:Photosynthesis; D014176:Protein Biosynthesis; D017510:Protein Folding; D013455:Sulfur / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism*
D000085:Acetates; D000596:Amino Acids; D005227:Fatty Acids; D013879:Thioredoxins; D013455:Sulfur; D002244:Carbon; D000255:Adenosine Triphosphate; D009584:Nitrogen