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Light-sensing via hydrogen peroxide and a peroxiredoxin

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Bodvard, Kristofer | Peeters, Ken | Roger, Friederike | Romanov, Natalie | Igbaria, Aeid | Welkenhuysen, Niek | Palais, Gael | Reiter, Wolfgang | Toledano, Michel B. | Käll, Mikael | Molin, Mikael

Edité par CCSD ; Nature Publishing Group -

International audience. Yeast lacks dedicated photoreceptors; however, blue light still causes pronounced oscillations of the transcription factor Msn2 into and out of the nucleus. Here we show that this poorly understood phenomenon is initiated by a peroxisomal oxidase, which converts light into a hydrogen peroxide (H$_2$ O$_2$) signal that is sensed by the peroxiredoxin Tsa1 and transduced to thioredoxin, to counteract PKA-dependent Msn2 phosphorylation. Upon H$_2$ O$_2$ , the nuclear retention of PKA catalytic subunits, which contributes to delayed Msn2 nuclear concentration , is antagonized in a Tsa1-dependent manner. Conversely, peroxiredoxin hyperoxidation interrupts the H$_2$ O$_2$ signal and drives Msn2 oscillations by superimposing on PKA feedback regulation. Our data identify a mechanism by which light could be sensed in all cells lacking dedicated photoreceptors. In particular, the use of H$_2$ O$_2$ as a second messenger in signalling is common to Msn2 oscillations and to light-induced entrainment of circadian rhythms and suggests conserved roles for peroxiredoxins in endogenous rhythms.

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