April 10, 2013
The SnRK2 subfamily of plant kinases is activated both by the hormone abscisic acid (ABA) and by dehydration stress in plants. Umezawaet al. analyzed the phosphoproteome and transcriptome of wild-type and SnRK2 triple-mutant plants exposed to ABA or dehydration. Motif analysis of the peptides that exhibited altered phosphorylation enabled the authors to identify both direct and indirect targets of SnRK2. The phosphoproteomic analysis indicated that SnRK2 primarily functioned in ABA signaling and regulated fewer targets in response to dehydration. Biochemical or genetic experiments confirmed the regulation of three of the SnRK2 targets in response to ABA: the mitogen-activated protein kinases AtMPK1 and AtMPK2, the transcription factor AREB1, and the previously uncharacterized protein SNS1.
Science Signaling doi: 10.1126/scisignal.2003509
T. Umezawa, N. Sugiyama, F. Takahashi, J. C. Anderson, Y. Ishihama, S.C. Peck, K. Shinozaki,
"Genetics and Phosphoproteomics Reveal a Protein Phosphorylation Network in the Abscisic Acid Signaling Pathway in Arabidopsis thaliana".
Gene Discovery Research Group