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Global Quantitative Analysis of Protein Phosphorylation Status in Fish Exposed to Microcystin

  • Karim Mezhoud
  • Daniele Praseuth
  • Jean-Christophe Francois
  • Cecile Bernard
  • Marc Edery
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 617)

Summary

The hepatotoxins, microcystins (MCs) are potent inhibitors of protein phosphatases PP1 and PP2A. These nonribosomal peptides are getting more and more attention because of their acute toxicity and potent tumor-promoting activity. These toxins are produced by freshwater cyanobacteria. Herein, we report a toxicological study conducted on aquatic animal models such as the medaka fish. To date, the detailed mechanisms underlying the toxicity of microcystins are unknown. MC-leucine-arginine (MC-LR) is the most toxic and the most commonly encountered variant of MCs in aquatic environment. It has been used for toxicological investigations on the liver of intoxicated medaka. We performed differential proteome analyses of MC-LR-treated and untreated medaka fish to investigate the mechanisms of establishment of early responses to the toxin. The identification of proteins involved in these early responses might constitute candidates of biomarkers of MC-LR exposure. Cytosolic proteins from livers of exposed or nonexposed medaka were resolved by 2D electrophoresis and detected using stains specific for phosphoproteins and for whole protein content. Overall, 15 spots were found to vary significantly on the proteomic 2D maps or on the phosphoproteomic 2D maps. Of these 15 proteins, only two could not be identified by mass spectrometry. Among the other proteins that were identified, phenylalanine hydroxylase and keratin 18 (type I) showed variations in phoshoryl content in agreement with inhibition of PP2A activity after exposure of the fish to MC-LR. The other identified proteins exhibited variations in their expression level. The identified proteins appear to be involved in cytoskeleton assembly, cell signalling, oxidative stress, and apoptosis. The functional implications of responses to MC-LR exposure of these proteins are discussed. The methodology described in this report should be widely used to a number of tissues and organisms, thus helping in the search for biomarkers of MC-LR contamination.

Keywords

Peptide Mass Fingerprinting NCBI Accession Phenylalanine Hydroxylase PP2A Activity Medaka Fish 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Jacquet C, et al. (2004) Effects of microcystin-LR on development of medaka fish embryos (Oryzias latipes).Toxicon 43, 141–147.PubMedCrossRefGoogle Scholar
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    Schulenberg B, Aggeler R, Beechem, et al. (2003) Analysis of steady-state protein phosphorylation in mitochondria using a novel fluorescent phosphosensor dye. J. Biol. Chem. 278, 27251–27255.PubMedCrossRefGoogle Scholar
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    Imanishi S, Harada K (2004) Proteomics approach on microcystin binding proteins in mouse liver for investigation of microcystin toxicity. Toxicon 43, 651–659.PubMedCrossRefGoogle Scholar

Copyright information

© Springer 2008

Authors and Affiliations

  • Karim Mezhoud
  • Daniele Praseuth
  • Jean-Christophe Francois
  • Cecile Bernard
  • Marc Edery
    • 1
  1. 1.Museum National D’Histoire NaturelleParisFrance

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