Discovering genome-wide thiol-dependent metabolic regulation in photosynthesis with redox chemoproteomics: CHLARABIDOX

Programme(s): H2020-EU.1.3.2. - Nurturing excellence by means of cross-border and cross-sector mobility

Topic(s): MSCA-IF-2019 - Individual Fellowships

Call for proposal: H2020-MSCA-IF-2019

Funding Scheme: MSCA-IF-GF - Global Fellowships

Grant agreement ID: 887992

Project description:

Coming out of the darkness: understanding metabolic fluxes in phototrophic eukaryotes

Most of us are familiar with circadian rhythms, oscillatory internal timing conforming to the 24-hour rotation of the Earth. Metabolic processes are strongly linked to them to optimise energy use across the light-dark cycle. Similarly, dark-light transitions are very important to phototrophs, which get their energy from sunlight through photosynthesis. Dark-light transitions provoke changes in the redox state of photosynthetic components that modulate metabolic fluxes. The EU-funded CHLARABIDOX project studies the proteome-wide dynamics in response to light in two phototrophic species (the green alga Chlamydomonas reinhardtii and the plant Arabidopsis thaliana). High temporal resolution of light-induced redox-related metabolic changes could help manipulate energy processes for biofuels production and identify modifications that help plants adjust to climate change.

Objective:

Most organisms exhibit a diurnal metabolic cycle, especially phototrophs, whose metabolism is strictly dependent on light. Dark-light transitions are accompanied by dramatic changes in the redox state of photosynthetic components, which drives redox-based post-translational modification of protein cysteines, whose oxidation state can considerably impact protein activity, and thus regulate metabolism. Given the central role of redox metabolism in biology, the operation of thiol-disulphide based switches are well-appreciated as a metabolic acclimation strategy, and the study of cysteine modifications in proteomes is a major interest of contemporary biology. The objective of CHLARABIDOX is to go beyond inventories of redox modified proteins by monitoring the proteome-wide dynamics of disulphide-dithiol status in the context of a diurnal metabolic cycle in phototrophic eukaryotes, specifically, the green alga Chlamydomonas reinhardtii and the land plant Arabidopsis thaliana. An innovative chemoproteomic isoTOP-ABPP approach will be used in an experimental design with deep temporal resolution to capture a good fraction of the proteome with site specificity and quantitative information about reactivity. The discoveries will be made in the context of a body of literature on thioredoxin-dependent redox regulation of central carbon metabolism, which will serve as a priori validation. The outcome of the project is a proteome-wide view of the operation of regulatory redox sensors, anchored to accompanying rich datasets on physiology, metabolic potential, transcriptomics, proteomics and central metabolites, which would inform the operation of light-driven metabolic networks. Both systems are compatible with downstream modelling of diurnal metabolic fluxes and validation by reverse genetics approaches. A long term impact on strategies for manipulating metabolism for biofuels production, or manipulating photosynthesis for better acclimation to climate change is also envisioned.