SnRK1 (SNF1-related kinase 1) has a central role in sugar and ABA signalling in Arabidopsis thaliana.
The proteins kinases SNF1/AMPK/SnRK1 are a subfamily of serine/threonine kinases that act as metabolite sensors to constantly adapt metabolism to the supply of, and demand for, energy. In the yeast Saccharomyces cerevisiae, the SNF1 complex is a central component of the regulatory response to glucose starvation. AMP activated protein kinase (AMPK) the mammalian homologue of SNF1, plays a central role in the regulation of energy homeostasis at the cellular as well as the whole-body levels. In Arabidopsis thaliana, SnRK1.1 and SnRK1.2 have recently been described as central integrators of a transcription network for stress and energy signalling. In this study, biochemical analysis established SnRK1.1 as the major SnRK1 isoform both in isolated cells and leaves. In order to elucidate the function of SnRK1.1 in Arabidopsis thaliana, transgenic plants over-expressing SnRK1.1 were produced. Genetic, biochemical, physiological and molecular analyses of these plants revealed that SnRK1.1 is implicated in sugar and ABA signalling pathways. Modifications of the starch and soluble sugar content were observed in the 35S:SnRK1.1 transgenic lines. Our studies also revealed modifications of the activity of essential enzymes such as nitrate reductase or ADP-glucose pyrophosphorylase, and of the expression of several sugar-regulated genes, confirming the central role of the protein kinase SnRK1 in the regulation of metabolism.
Jossier
Mathieu
M
Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France.
Bouly
Jean-Pierre
JP
Meimoun
Patrice
P
Arjmand
Alaleh
A
Lessard
Philippe
P
Hawley
Simon
S
Grahame Hardie
D
D
Thomas
Martine
M
D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D018506:Gene Expression Regulation, Plant; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D020033:Protein Isoforms; D017346:Protein Serine-Threonine Kinases; C531469:At3g01090 protein, Arabidopsis