title: Quantitative phosphoproteomics reveals the role of the AMPK plant ortholog SnRK1 as a metabolic master regulator under energy deprivation.
abstract: Since years, research on SnRK1, the major cellular energy sensor in plants, has tried to define its role in energy signalling. However, these attempts were notoriously hampered by the lethality of a complete knockout of SnRK1. Therefore, we generated an inducible amiRNA::SnRK1α2 in a snrk1α1 knock out background (snrk1α1/α2) to abolish SnRK1 activity to understand major systemic functions of SnRK1 signalling under energy deprivation triggered by extended night treatment. We analysed the in vivo phosphoproteome, proteome and metabolome and found that activation of SnRK1 is essential for repression of high energy demanding cell processes such as protein synthesis. The most abundant effect was the constitutively high phosphorylation of ribosomal protein S6 (RPS6) in the snrk1α1/α2 mutant. RPS6 is a major target of TOR signalling and its phosphorylation correlates with translation. Further evidence for an antagonistic SnRK1 and TOR crosstalk comparable to the animal system was demonstrated by the in vivo interaction of SnRK1α1 and RAPTOR1B in the cytosol and by phosphorylation of RAPTOR1B by SnRK1α1 in kinase assays. Moreover, changed levels of phosphorylation states of several chloroplastic proteins in the snrk1α1/α2 mutant indicated an unexpected link to regulation of photosynthesis, the main energy source in plants.
authors.affiliation: Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.
authors.forename: Ella
authors.initials: E
authors.lastname: Nukarinen
authors.affiliation: Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.|Vienna Metabolomics Center (VIME), University of Vienna, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nägele
authors.affiliation: Julius-von-Sachs-Institut, Julius-Maximilians-Universität Würzburg, Würzburg, Germany.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pedrotti
authors.affiliation: Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wurzinger
authors.affiliation: Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mair
authors.affiliation: Plant Health, Plant Metabolism Group, Leibniz-Institute of Vegetable and Ornamental Crops, Großbeeren, Germany.
authors.forename: Ramona
authors.initials: R
authors.lastname: Landgraf
authors.affiliation: Plant Health, Plant Metabolism Group, Leibniz-Institute of Vegetable and Ornamental Crops, Großbeeren, Germany.|Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Börnke
authors.affiliation: Department of Plant Physiology, Umeå University, Umeå, Sweden.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hanson
authors.affiliation: Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Teige
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, Portugal.
authors.forename: Elena
authors.initials: E
authors.lastname: Baena-Gonzalez
authors.affiliation: Julius-von-Sachs-Institut, Julius-Maximilians-Universität Würzburg, Würzburg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dröge-Laser
authors.affiliation: Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.|Vienna Metabolomics Center (VIME), University of Vienna, Vienna, Austria.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Weckwerth
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics
chemical_list: D029681:Arabidopsis Proteins; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; C531469:At3g01090 protein, Arabidopsis