Exploring the chloroplast ABC1-like kinase phosphoprotein network: roles in remodeling thylakoid lipid composition, photosynthesis and beyond
| Responsable du projet | Félix Kessler |
| Résumé |
Countless cellular processes are regulated by protein
phosphorylation. Kinases transfer the phosphate groups to specific
target proteins. Addition of a phosphate group may affect the
activity or the ability of the substrate to interact with other
proteins. Phosphatase activity is directly opposite to kinase
activity and removes phosphate groups from target proteins
reversing its effects. In agreement with the large number of
processes regulated by protein phosphorylation the Arabidopsis
genome accounts for an estimated 1160 kinases. However,
surprisingly few predicted kinases (around a dozen) are present in
chloroplasts. The best studied of these kinases are STN7 and STN8
implicated in state transition and D1 repair at the thylakoid
membrane and thus function to optimize photosynthetic activity at
the protein level. In contrast, the non-typical ABC1-like kinases
(ABC1Ks) in chloroplasts reside on lipid droplets (plastoglobules,
PG) 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) and photoprotectants (carotenoids). This
project aims at unraveling the ABC1K phosphoprotein network using
state of the art techniques including phosphoproteomics using the
Chlorophos 1.0 peptide chip covering the known chloroplast
phosphoproteome and lipidomics to analyze the downstream effects of
target phosphorylation. The question whether the prototypical
ABC1-like is itself a target of kinase regulation will be
addressed. By analyzing the known ABC1K target, tocopherol cyclase
(VTE1) we will determine whether phosphorylation affects activity
of the enzyme or its attachment to its site of action, the lipid
droplets. The effects of ABC1K activity on lipid droplet protein
and lipid composition will also be determined. The results will
give important insight in the activity of the major group of
chloroplast kinases and give way to translation into crop plants
such as tomato. |
| Mots-clés |
Photosynthesis, Phosphoprotein network, Chloroplast, Phosphorylation, Lipid metabolism, Plastoglobules, Kinase, Lipids droplets, Phosphoproteomics |
| Type de projet | Recherche fondamentale |
| Domaine de recherche | Biologie cellulaire, cytologie |
| Source de financement | FNS - Encouragement de projets (Div. I-III) |
| Etat | Terminé |
| Début de projet | 1-1-2015 |
| Fin du projet | 31-12-2017 |
| Budget alloué | 429'814.00 |
| Contact | Félix Kessler |