title: Tobacco transcription factor WRKY1 is phosphorylated by the MAP kinase SIPK and mediates HR-like cell death in tobacco.
abstract: The salicylic acid-induced protein kinase (SIPK) of tobacco, which is a mitogen-activated protein kinase (MAPK), is activated by various biotic and abiotic treatments. Overexpression of SIPK has been shown to trigger cell death. In this study, a targeted yeast two-hybrid approach identified the tobacco transcription factor WRKY1 as a potential substrate. SIPK phosphorylated WRKY1, which resulted in enhanced DNA-binding activity of WRKY1 to its cognate binding site, a W box sequence from the tobacco chitinase gene CHN50. SIPK-mediated enhancement of WRKY1 DNA-binding activity was inhibited by staurosporine, a general kinase inhibitor. Co-expression of SIPK and WRKY1 in Nicotiana benthamiana led to more rapid cell death than expression of SIPK alone, suggesting that WRKY1 is involved in the formation of hypersensitive response-like cell death and may be a component of the signaling cascade downstream of SIPK.
authors.affiliation: Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
authors.forename: Frank L H
authors.initials: FL
authors.lastname: Menke
authors.forename: Hong-Gu
authors.initials: HG
authors.lastname: Kang
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Chen
authors.forename: Jeong Mee
authors.initials: JM
authors.lastname: Park
authors.forename: Dhirendra
authors.initials: D
authors.lastname: Kumar
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Klessig
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism* / Q000502:physiology; D016923:Cell Death / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D024202:Electrophoretic Mobility Shift Assay; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D010940:Plant Proteins; D030821:Plants, Genetically Modified; D011485:Protein Binding; D014026:Nicotiana / Q000166:cytology* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism* / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors; C499621:ZAP1 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; C106405:SA-induced protein kinase