The plant TOR pathway: impact on translation – TRANSLATOR
Signaling and adaptation of plants to the environment
Mecanistic studies of signaling pathways involving the TOR protein and its link with protein synthesis in Arabidopsis thaliana
Study of molecular mechanisms involved in signaling and adaption to the environment in plants
Plant growth is plastic and adapts to the environment. Growth is strongly linked to protein synthesis. The eucaryotic TOR kinase is an environmental sensor that modify protein synthesis. The goal of the project is to understand plant specific molecular feature lying upstream of TOR, protein complexes involving TOR and its links with protein synthesis.
Protein complexes involving the Arabidopsis TOR kinase will be purified using affinity chromatography of tagged proteins or m7GTP affinity (for cap binding complex proteins) Proteomic analysis will reveal proteins differentailly associated or differentially phosphorylated when the TOR kinase is inactivated either genetically or pharmacologically. Reverse genetic analysis of the corresponding genes will indicate their role in signaling and protein synthesis.
Proteomic analysis of complexes associated to mRNA m7GTP cap , ribosomal complexes polysomal complexes has been undertaken. The differential phospphorylation of the S6 ribosomal protein was confirmed (some of this work was undetaken before the beginning of the project)
The project is still is still in its developement phase. Proteins differentially associated with cap complexes, ribosomes and polysomes will tested for their phosphorylation by the TOR kinase. An in vivo or in vitro TOR phosphorylation assay will have to be set up. The role of candidates proteins on protein synthesis will be then adressed in vivo and in vitro.
Prospective and Review paper discussing future researchs concerning the TOR and SnRK signaling in plants.
Sensing nutrient and energy status by SnRK1 and TOR kinases.
Robaglia C, Thomas M, Meyer C.
Curr Opin Plant Biol. 2012 Jun;15(3):301-7. Epub 2012 Feb 2.
The integration of signals originating from nutritional, biotic and abiotic stresses (environmental changes, starvation, pathogens) to drive and adjust growth and development is at the heart of life. One major signaling pathway connecting environnemental perception to growth decisions is known as the TOR (Target Of Rapamycin) pathway, which has been identified in all eucaryotes. TOR is a very large protein kinase engaged in several complexes that act in a direct or indirect fashion on many cellular processes and particularly on the protein synthesis machinery (mRNA translation and ribosome biogenesis). The plant TOR pathway is less well described than in other organisms. Plants, as immobile organisms, have a strong need to continually monitor environmental inputs, including the presence of pathogens, and to transduce them into growth processes which are particularly plastic in plants. This project concerns the study of the plant TOR pathway using Arabidopsis thaliana as a model system. The main objective is to determine the role of the TOR pathway in the control of translation and ribosome biogenesis in both normal and stressed conditions and to integrate it with our knowledge of the adaptation of plants to abiotic and biotic stresses. We will identify and investigate targets of the TOR pathway in the translational machinery, using biochemical purification of translation initiation complexes and polysomes, and the role of the TOR pathway in regulating translation in interaction with the eIF3 translation initiation factor. This project also includes the study of a viral protein that triggers reinitiation of mRNA translation and recruits the TOR protein. We will then investigate the connection between the TOR pathway and the phytohormones abscissic acid (ABA) and salycilic acid (SA) which are involved in stress responses. This consortium of laboratories has pionneered the study of the plant TOR pathway and has long standing knowledge in translational control of cellular and viral RNA and in the regulation of plant signaling pathways.
Monsieur christophe ROBAGLIA (UNIVERSITE AIX-MARSEILLE II [DE LA MEDITERRANEE]) – firstname.lastname@example.org
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
INRA-IJPB INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE - CENTRE DE RECHERCHE DE VERSAILLES GRIGNON
CNRS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE ALSACE
LGBP UMR6191 UNIVERSITE AIX-MARSEILLE II [DE LA MEDITERRANEE]
Help of the ANR 440,992 euros
Beginning and duration of the scientific project: December 2011 - 48 Months