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An inositol polyphosphate 5‐phosphatase: SNF1‐like kinase complex is involved in ABA response in Arabidopsis plants
Author(s) -
Ananieva Elitsa Antonova,
Erickson F Les,
Ely Amanda,
Gillaspy Glenda E
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a257
Subject(s) - arabidopsis , inositol , phosphatase , signal transduction , kinase , mutant , second messenger system , biology , microbiology and biotechnology , arabidopsis thaliana , biochemistry , protein kinase a , polyphosphate , phosphorylation , gene , receptor , phosphate
Inositol signaling pathways are important for many different developmental and physiological processes in eukaryotes. In plants, inositol signaling is used during drought stress, with the drought hormone, ABA, causing an increase in second messenger Ins(1,4,5)P3 levels. In order to better understand inositol signaling pathways in plants, we have investigated Arabidopsis inositol polyphosphate 5‐phosphatases (EC 3.1.3.56 ; At5PTase). Like some other plant 5PTase enzymes, At5PTase13 is unique in that it contains WD repeats implicated in protein‐protein interactions. We used the WD region as bait in the yeast two‐hybrid system to identify protein partners of At5PTase13. We identified the Arabidopsis SNF1‐like kinase as an interacting protein and confirmed this interaction in vitro. The plant SNF1‐like kinases have been implicated in stress signaling pathways, so we characterized At5PTase13 loss‐of‐function mutants and their response to stresses. We found that two mutants, At5pt13‐1 and At5pt13‐2 display decreased sensitivity to ABA in a concentration dependent manner. Consistent with the decreased sensitivity to ABA, the endogenous Ins(1,4,5)P3 level is reduced in both mutants upon exposure to 6% glucose which induces ABA synthesis. Together these data suggest that plants use an At5PTase13:SNF1‐like kinase complex as an Ins(1,4,5)P3 sensor to control drought‐sensing signal transduction pathways. USDA NRI award to G.G.