Mapping the diatom redox-sensitive proteome provides insight into response to nitrogen stress in the marine environment

Shilo Rosenwasser, Shiri Graff van Creveld, Daniella Schatz, Sergey Malitsky, Oren Tzfadia, Asaph Aharoni, Yishai Levin, Alexandra Gabashvili, Ester Feldmesser, Assaf Vardi

Research output: Contribution to journalArticle

Abstract

Diatoms are ubiquitous marine photosynthetic eukaryotes responsible for approximately 20% of global photosynthesis. Little is known about the redox-based mechanisms that mediate diatom sensing and acclimation to environmental stress. Here we used a quantitative mass spectrometry-based approach to elucidate the redox-sensitive signaling network (redoxome) mediating the response of diatoms to oxidative stress. We quantified the degree of oxidation of 3,845 cysteines in the Phaeodactylum tricornutum proteome and identified approximately 300 redox-sensitive proteins. Intriguingly, we found redox-sensitive thiols in numerous enzymes composing the nitrogen assimilation pathway and the recently discovered diatom urea cycle. In agreement with this finding, the flux from nitrate into glutamine and glutamate, measured by the incorporation of (15)N, was strongly inhibited under oxidative stress conditions. Furthermore, by targeting the redox-sensitive GFP sensor to various subcellular localizations, we mapped organelle-specific oxidation patterns in response to variations in nitrogen quota and quality. We propose that redox regulation of nitrogen metabolism allows rapid metabolic plasticity to ensure cellular homeostasis, and thus is essential for the ecological success of diatoms in the marine ecosystem.

Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number7
Pages (from-to)2740-5
Number of pages6
ISSN0027-8424
DOIs
Publication statusPublished - 18-Feb-2014

Keywords

  • Acclimatization/physiology
  • Chromatography, Liquid
  • Diatoms/metabolism
  • Homeostasis/physiology
  • Mass Spectrometry
  • Nitrogen/metabolism
  • Oxidation-Reduction
  • Oxidative Stress/genetics
  • Proteome/metabolism
  • Signal Transduction/physiology

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