Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism - CEA - Commissariat à l’énergie atomique et aux énergies alternatives Accéder directement au contenu
Article Dans Une Revue Proceedings of the National Academy of Sciences of the United States of America Année : 2015

Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism

Xiaobo Li
Jaruswan Warakanont
  • Fonction : Auteur
Alexandra Dubini
  • Fonction : Auteur
Mark Page
  • Fonction : Auteur
Sarah D’adamo
  • Fonction : Auteur
Marko Boehm
  • Fonction : Auteur
Christoph Benning
  • Fonction : Auteur
Sabeeha Merchant
  • Fonction : Auteur
Matthew Posewitz
  • Fonction : Auteur
Arthur Grossman

Résumé

Photosynthetic microorganisms typically have multiple isoforms of the electron transfer protein ferredoxin, although we know little about their exact functions. Surprisingly, a Chlamydomonas reinhardtii mutant null for the ferredoxin-5 gene (FDX5) completely ceased growth in the dark, with both photosynthetic and respiratory functions severely compromised; growth in the light was unaffected. Thylakoid membranes in dark-maintained fdx5 mutant cells became severely disorganized concomitant with a marked decrease in the ratio of monogalactosyldiacylglycerol to digalactosyldiacylglycerol, major lipids in photosynthetic membranes, and the accumulation of triacylglycerol. Furthermore, FDX5 was shown to physically interact with the fatty acid desaturases CrΔ4FAD and CrFAD6, likely donating electrons for the desaturation of fatty acids that stabilize monogalactosyldiacylglycerol. Our results suggest that in photosynthetic organisms, specific redox reactions sustain dark metabolism, with little impact on daytime growth, likely reflecting the tailoring of electron carriers to unique intracellular metabolic circuits under these two very distinct redox conditions.

Dates et versions

cea-01820387 , version 1 (21-06-2018)

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Citer

Wenqiang Yang, Tyler Wittkopp, Xiaobo Li, Jaruswan Warakanont, Alexandra Dubini, et al.. Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism. Proceedings of the National Academy of Sciences of the United States of America, 2015, 112 (48), pp.14978 - 14983. ⟨10.1073/pnas.1515240112⟩. ⟨cea-01820387⟩
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