title: The impact of Arabidopsis thaliana SNF1-related-kinase 1 (SnRK1)-activating kinase 1 (SnAK1) and SnAK2 on SnRK1 phosphorylation status: characterization of a SnAK double mutant.
abstract: Arabidopsis thaliana SNF1-related-kinase 1 (SnRK1)-activating kinase 1 (AtSnAK1) and AtSnAK2 have been shown to phosphorylate in vitro and activate the energy signalling integrator, SnRK1. To clarify this signalling cascade in planta, a genetic- and molecular-based approach was developed. Homozygous single AtSnAK1 and AtSnAK2 T-DNA insertional mutants did not display an apparent phenotype. Crossing of the single mutants did not allow the isolation of double-mutant plants, whereas self-pollinating the S1-/- S2+/- sesquimutant specifically gave approximatively 22% individuals in their offspring that, when rescued on sugar-supplemented media in vitro, were shown to be AtSnAK1 AtSnAK2 double mutants. Interestingly, this was not obtained in the case of the other sesquimutant, S1+/- S2-/-. Although reduced in size, the double mutant had the capacity to produce flowers, but not seeds. Immunological characterization established the T-loop of the SnRK1 catalytic subunit to be non-phosphorylated in the absence of both SnAKs. When the double mutant was complemented with a DNA construct containing an AtSnAK2 open reading frame driven by its own promoter, a normal phenotype was restored. Therefore, wild-type plant growth and development is dependent on the presence of SnAK in vivo, and this is correlated with SnRK1 phosphorylation. These data show that both SnAKs are kinases phosphorylating SnRK1, and thereby they contribute to energy signalling in planta.
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Glab
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Oury
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Guérinier
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Domenichini
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Crozet
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Vidal
authors.affiliation: Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Sud, INRA, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Université Paris-Saclay, Bâtiment 630, 91405, Orsay Cedex, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Hodges
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D016366:Open Reading Frames / Q000235:genetics; D010766:Phosphorylation / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D017346:Protein Serine-Threonine Kinases; C490996:At5g01820 protein, Arabidopsis
keywords: 
  Arabidopsis thaliana
  ; SNF1-related protein kinase-1; SnRK1-activating kinase; double mutant; phosphorylation; signalling cascade