Arabidopsis eIF2alpha kinase GCN2 is essential for growth in stress conditions and is activated by wounding.
BACKGROUND
Phosphorylation of eIF2alpha provides a key mechanism for down-regulating protein synthesis in response to nutrient starvation or stresses in mammalian and yeast cells. However, this process has not been well characterized in plants


RESULTS
We show here that in response to amino acid and purine starvations, UV, cold shock and wounding, the Arabidopsis GCN2 kinase (AtGCN2) is activated and phosphorylates eIF2alpha. We show that AtGCN2 is essential for plant growth in stress situations and that its activity results in a strong reduction in global protein synthesis.


CONCLUSIONS
Our results suggest that a general amino acid control response is conserved between yeast and plants but that the plant enzyme evolved to fulfill a more general function as an upstream sensor and regulator of diverse stress-response pathways. The activation of AtGCN2 following wounding or exposure to methyl jasmonate, the ethylene precursor 1-Aminocyclopropane-1-carboxylic acid (ACC) and salicylic acid, further suggests that this enzyme could play a role in plant defense against insect herbivores.
Lageix
Sébastien
S
Université de Perpignan Via Domitia, CNRS-IRD UMR5096 LGDP, 52 avenue Paul Alduy, 66860 Perpignan Cedex, France. Sebastien.LAGEIX@univ-bpclermont.fr
Lanet
Elodie
E
Pouch-Pélissier
Marie-Noëlle
MN
Espagnol
Marie-Claude
MC
Robaglia
Christophe
C
Deragon
Jean-Marc
JM
Pélissier
Thierry
T
D000085:Acetates / Q000494:pharmacology; D000596:Amino Acids / Q000378:metabolism; D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000494:pharmacology; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D054883:Oxylipins / Q000494:pharmacology; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020156:Salicylic Acid / Q000494:pharmacology; D013312:Stress, Physiological
D000085:Acetates; D000596:Amino Acids; D000598:Amino Acids, Cyclic; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D015852:Eukaryotic Initiation Factor-2; D054883:Oxylipins; C023863:1-aminocyclopropane-1-carboxylic acid; C072239:methyl jasmonate; D011494:Protein Kinases; C480318:GCN2 protein, Arabidopsis; D020156:Salicylic Acid