title: Stress-responsive mitogen-activated protein kinases interact with the EAR motif of a poplar zinc finger protein and mediate its degradation through the 26S proteasome.
abstract: Mitogen-activated protein kinases (MAPKs) contribute to the establishment of plant disease resistance by regulating downstream signaling components, including transcription factors. In this study, we identified MAPK-interacting proteins, and among the newly discovered candidates was a Cys-2/His-2-type zinc finger protein named PtiZFP1. This putative transcription factor belongs to a family of transcriptional repressors that rely on an ERF-associated amphiphilic repression (EAR) motif for their repression activity. Amino acids located within this repression motif were also found to be essential for MAPK binding. Close examination of the primary protein sequence revealed a functional bipartite MAPK docking site that partially overlaps with the EAR motif. Transient expression assays in Arabidopsis (Arabidopsis thaliana) protoplasts suggest that MAPKs promote PtiZFP1 degradation through the 26S proteasome. Since features of the MAPK docking site are conserved among other EAR repressors, our study suggests a novel mode of defense mechanism regulation involving stress-responsive MAPKs and EAR repressors.
authors.affiliation: Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, Quebec, Canada.
authors.forename: Louis-Philippe
authors.initials: LP
authors.lastname: Hamel
authors.forename: Meriem
authors.initials: M
authors.lastname: Benchabane
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Nicole
authors.forename: Ian T
authors.initials: IT
authors.lastname: Major
authors.forename: Marie-Josée
authors.initials: MJ
authors.lastname: Morency
authors.forename: Gervais
authors.initials: G
authors.lastname: Pelletier
authors.forename: Nathalie
authors.initials: N
authors.lastname: Beaudoin
authors.forename: Jen
authors.initials: J
authors.lastname: Sheen
authors.forename: Armand
authors.initials: A
authors.lastname: Séguin
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D017360:Arabidopsis / Q000378:metabolism; D001665:Binding Sites; D002467:Cell Nucleus / Q000201:enzymology; D017124:Conserved Sequence / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D018515:Plant Leaves / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D032107:Populus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D059748:Proteolysis; D011523:Protoplasts / Q000378:metabolism; D016335:Zinc Fingers
chemical_list: D000596:Amino Acids; D010940:Plant Proteins; D020928:Mitogen-Activated Protein Kinases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease