Exploring the chloroplast ABC1-like kinase phosphoprotein network: roles in remodeling thylakoid lipid composition, photosynthesis and beyond.

At the beginning of 2015, we launched a new project that will examine the role that the recently discovered ABC1-kinases play in the regulation of vitamin E content of plants and in the protection against harmful oxidative stress. Countless cellular processes are regulated by protein phosphorylation, including photosynthesis in plants. Kinases transfer the phosphate groups to specific target proteins, which may affect their ability to interact with other proteins. Phosphatases act in the opposite way and reverse the effects of kinases by removing phosphate groups from target proteins. In chloroplasts, non-typical ABC1-like kinases reside on lipid droplets, the so-called plastoglobules, and function to optimize photosynthesis by modifying the neutral lipid composition of the thylakoid membrane. This includes key electron transporters (plastoquinone and phylloquinone), antioxidants (tocopherols aka vitamin E) and photoprotectants (carotenoids). For example, under high light conditions, a plant produces much more vitamin E to protect the photosynthetic apparatus from oxidation. The project aims at unravelling the role of the ABC1 kinase phosphoprotein network in this process. It will strongly rely on the continued services of the Neuchâtel Platform of Analytical Chemistry (NPAC), which is implied in metabolomics analyses. The results of the project will provide important insight into the activity of the major group of chloroplast kinases and give opportunities for translation into crop plants. Modern techniques will be employed to screen for new tomato varieties, which thanks to mutations in the ABC1 kinases naturally produce large amounts of vitamin E.

research database P3 of SNF