Cellular Metabolites Enhance the Light Sensitivity of Arabidopsis Cryptochrome through Alternate Electron Transfer Pathways - Biological Adaptation and Ageing Accéder directement au contenu
Article Dans Une Revue The Plant cell Année : 2014

Cellular Metabolites Enhance the Light Sensitivity of Arabidopsis Cryptochrome through Alternate Electron Transfer Pathways

Christopher Engelhard
  • Fonction : Auteur
Xuecong Wang
  • Fonction : Auteur
David Robles
  • Fonction : Auteur
Julia Moldt
  • Fonction : Auteur
Lars-Oliver Essen
Alfred Batschauer
  • Fonction : Auteur
Robert Bittl
  • Fonction : Auteur
Margaret Ahmad
  • Fonction : Auteur

Résumé

Cryptochromes are blue light receptors with multiple signaling roles in plants and animals. Plant cryptochrome (cry1 and cry2) biological activity has been linked to flavin photoreduction via an electron transport chain comprising three evolutionarily conserved tryptophan residues known as the Trp triad. Recently, it has been reported that cry2 Trp triad mutants, which fail to undergo photoreduction in vitro, nonetheless show biological activity in vivo, raising the possibility of alternate signaling pathways. Here, we show that Arabidopsis thaliana cry2 proteins containing Trp triad mutations indeed undergo robust photoreduction in living cultured insect cells. UV/Vis and electron paramagnetic resonance spectroscopy resolves the discrepancy between in vivo and in vitro photochemical activity, as small metabolites, including NADPH, NADH, and ATP, were found to promote cry photoreduction even in mutants lacking the classic Trp triad electron transfer chain. These metabolites facilitate alternate electron transfer pathways and increase light-induced radical pair formation. We conclude that cryptochrome activation is consistent with a mechanism of light-induced electron transfer followed by flavin photoreduction in vivo. We further conclude that in vivo modulation by cellular compounds represents a feature of the cryptochrome signaling mechanism that has important consequences for light responsivity and activation.

Dates et versions

hal-01545369 , version 1 (22-06-2017)

Identifiants

Citer

Christopher Engelhard, Xuecong Wang, David Robles, Julia Moldt, Lars-Oliver Essen, et al.. Cellular Metabolites Enhance the Light Sensitivity of Arabidopsis Cryptochrome through Alternate Electron Transfer Pathways. The Plant cell, 2014, 26 (11), pp.4519-4531. ⟨10.1105/tpc.114.129809⟩. ⟨hal-01545369⟩
112 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More