Regulatory interaction of PRL1 WD protein with Arabidopsis SNF1-like protein kinases
- Rishikesh P. Bhalerao*,†,
- Klaus Salchert*,
- László Bakó*,
- László Ökrész‡,
- László Szabados‡,
- Toshiya Muranaka§,
- Yasunori Machida¶,
- Jeff Schell*, and
- Csaba Koncz*,‡,‖
- *Max-Planck Institut für Züchtungsforschung, D-50829 Cologne, Germany; ‡Institute of Plant Biology, Biological Research Center of Hungarian Academy of Sciences, H-6701 Szeged, Hungary; §Biotechnology Laboratory, Sumitomo Chemical Co. Ltd., Hyogo 665, Japan; and ¶Department of Biology, Faculty of Science, Nagoya University, Nagoya 464-01, Japan
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Contributed by Jeff Schell
Abstract
Mutation of the PRL1 gene, encoding a regulatory WD protein, results in glucose hypersensitivity and derepression of glucose-regulated genes in Arabidopsis. The yeast SNF1 protein kinase, a key regulator of glucose signaling, and Arabidopsis SNF1 homologs AKIN10 and AKIN11, which can complement the Δsnf1 mutation, were found to interact with an N-terminal domain of the PRL1 protein in the two-hybrid system and in vitro. AKIN10 and AKIN11 suppress the yeast Δsnf4 mutation and interact with the SNF4p-activating subunit of SNF1. PRL1 and SNF4 bind independently to adjacent C-terminal domains of AKIN10 and AKIN11, and these protein interactions are negatively regulated by glucose in yeast. AKIN10 and AKIN11, purified in fusion with glutathione S-transferase, undergo autophosphorylation and phosphorylate a peptide of sucrose phosphate synthase in vitro. The sucrose phosphate synthase-peptide kinase activity of AKIN complexes detected by immunoprecipitation is stimulated by sucrose in light-grown Arabidopsis plants. In comparison with wild type, the activation level of AKIN immunocomplexes is higher in the prl1 mutant, suggesting that PRL1 is a negative regulator of Arabidopsis SNF1 homologs. This conclusion is supported by the observation that PRL1 is an inhibitor of AKIN10 and AKIN11 in vitro.
Footnotes
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↵ † Present address: Department of Forest Genetics and Plant Physiology, The Swedish University of Agricultural Sciences, S-90183 Umea, Sweden.
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↵ ‖ To whom reprint requests should be addressed at: Max-Planck Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany. e-mail: koncz{at}mpiz-koeln.mpg.de.
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Data deposition: The sequences reported in this paper have been deposited in the GenBank database [accession nos. X99279 (AKIN11) and AJ006021 (PIPC)].
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A Commentary on this article begins on page 4746.
- ABBREVIATIONS:
- PRL1,
- Arabidopsis pleiotropic regulatory locus;
- AKIN,
- Arabidopsis SNF1 kinase homolog;
- GST,
- glutathione S-transferase, GBD, GAL4 DNA-binding domain;
- GAD,
- GAL4 activation domain, TRX, thioredoxin;
- SPS,
- sucrose phosphate synthase
- Copyright © 1999, The National Academy of Sciences
