Publication Information
Wang et al., 2013
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Abstract
Proc Natl Acad Sci U S A. 2013 Jul 2;110(27):11205-10. doi:
10.1073/pnas.1308974110. Epub 2013 Jun 17.
Quantitative phosphoproteomics identifies SnRK2 protein kinase substrates and
reveals the effectors of abscisic acid action.
Wang P(1), Xue L, Batelli G, Lee S, Hou YJ, Van Oosten MJ, Zhang H, Tao WA, Zhu
JK.
Author information:
(1)Department of Horticulture and Landscape Architecture, Purdue University,
West Lafayette, IN 47907, USA.
Sucrose nonfermenting 1 (SNF1)-related protein kinase 2s (SnRK2s) are central
components of abscisic acid (ABA) signaling pathways. The snrk2.2/2.3/2.6
triple-mutant plants are nearly completely insensitive to ABA, suggesting that
most of the molecular actions of ABA are triggered by the SnRK2s-mediated
phosphorylation of substrate proteins. Only a few substrate proteins of the
SnRK2s are known. To identify additional substrate proteins of the SnRK2s and
provide insight into the molecular actions of ABA, we used quantitative
phosphoproteomics to compare the global changes in phosphopeptides in WT and
snrk2.2/2.3/2.6 triple mutant seedlings in response to ABA treatment. Among the
5,386 unique phosphorylated peptides identified in this study, we found that ABA
can increase the phosphorylation of 166 peptides and decrease the
phosphorylation of 117 peptides in WT seedlings. In the snrk2.2/2.3/2.6 triple
mutant, 84 of the 166 peptides, representing 58 proteins, could not be
phosphorylated, or phosphorylation was not increased under ABA treatment. In
vitro kinase assays suggest that most of the 58 proteins can serve as substrates
of the SnRK2s. The SnRK2 substrates include proteins involved in flowering time
regulation, RNA and DNA binding, miRNA and epigenetic regulation, signal
transduction, chloroplast function, and many other cellular processes.
Consistent with the SnRK2 phosphorylation of flowering time regulators, the
snrk2.2/2.3/2.6 triple mutant flowered significantly earlier than WT. These
results shed new light on the role of the SnRK2 protein kinases and on the
downstream effectors of ABA action, and improve our understanding of plant
responses to adverse environments.
DOI: 10.1073/pnas.1308974110
PMCID: PMC3703982
PMID: 23776212 [Indexed for MEDLINE]
Conflict of interest statement: The authors declare no conflict of interest.
