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Article Dans Une Revue PLoS ONE Année : 2017

Blue-light induced accumulation of reactive oxygen species is a consequence of the Drosophila cryptochrome photocycle

Mohamed El-Esawi
  • Fonction : Auteur
Alain d'Harlingue
  • Fonction : Auteur
Pierre-Etienne Bouchet
  • Fonction : Auteur
Jacques Witczak
  • Fonction : Auteur
Thorsten Ritz
  • Fonction : Auteur
Andre Klarsfeld
  • Fonction : Auteur
Serge Birman
Robert J. Usselman
  • Fonction : Auteur
Ute Hoecker
  • Fonction : Auteur
Carlos F. Martino
  • Fonction : Auteur
Margaret Ahmad
  • Fonction : Auteur
Louis-David Arthaut
  • Fonction : Auteur
Nathalie Jourdan
  • Fonction : Auteur
Ali Mteyrek
  • Fonction : Auteur
Maria Procopio
  • Fonction : Auteur

Résumé

Cryptochromes are evolutionarily conserved blue-light absorbing flavoproteins which participate in many important cellular processes including in entrainment of the circadian clock in plants, Drosophila and humans. Drosophila melanogaster cryptochrome (DmCry) absorbs light through a flavin (FAD) cofactor that undergoes photoreduction to the anionic radical (FAD(center dot-)) redox state both in vitro and in vivo. However, recent efforts to link this photoconversion to the initiation of a biological response have remained controversial. Here, we show by kinetic modeling of the DmCry photocycle that the fluence dependence, quantum yield, and half-life of flavin redox state interconversion are consistent with the anionic radical (FAD(center dot-)) as the signaling state in vivo. We show by fluorescence detection techniques that illumination of purified DmCry results in enzymatic conversion of molecular oxygen (O-2) to reactive oxygen species (ROS). We extend these observations in living cells to demonstrate transient formation of superoxide (O-2(center dot-)), and accumulation of hydrogen peroxide (H2O2) in the nucleus of insect cell cultures upon DmCry illumination. These results define the kinetic parameters of the Drosophila cryptochrome photocycle and support light-driven electron transfer to the flavin in DmCry signaling. They furthermore raise the intriguing possibility that light-dependent formation of ROS as a byproduct of the cryptochrome photocycle may contribute to its signaling role.

Dates et versions

hal-01545362 , version 1 (22-06-2017)

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Citer

Mohamed El-Esawi, Alain d'Harlingue, Pierre-Etienne Bouchet, Jacques Witczak, Thorsten Ritz, et al.. Blue-light induced accumulation of reactive oxygen species is a consequence of the Drosophila cryptochrome photocycle. PLoS ONE, 2017, 12 (3), pp.e0171836. ⟨10.1371/journal.pone.0171836⟩. ⟨hal-01545362⟩
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