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

Louis-Philippe Hamel,Marie-Josée Morency,Armand Séguin,Meriem Benchabane,Nathalie Beaudoin,Ian T Major,Jen Sheen,Gervais Pelletier,Marie-Claude Nicole

doi:10.1104/pp.111.178343

Louis-Philippe Hamel, Marie-Josée Morency + Show 7 more

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https://doi.org/10.1104/pp.111.178343

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Journal: Plant Physiology	Publication Date: Aug 26, 2011
Citations: 29	License type: CC BY 4.0

Affiliation: Massachusetts General Hospital

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.

Highlights

Mitogen-activated protein kinases (MAPKs) contribute to the establishment of plant disease resistance by regulating downstream signaling components, including transcription factors
Given the importance of AtMPK3 in both the priming (Beckers et al, 2009) and regulation of defense mechanisms against bacteria and fungi (Asai et al, 2002; Ren et al, 2008), a yeast two-hybrid screen was performed to find putative interactors of poplar PtiMPK3-1. This approach allowed the identification of a novel MAPK-interacting protein, P. trichocarpa Zinc Finger Protein1 (PtiZFP1), a Transcription factors (TFs) that belongs to the Cys-2/His-2type zinc finger protein family and that is characterized by the presence of an ERF-associated amphiphilic repression (EAR) motif at the C terminus
To address the question of MAPK function in stress signal transduction, we searched for proteins that interact with PtiMPK3-1

Summary

Introduction

Mitogen-activated protein kinases (MAPKs) contribute to the establishment of plant disease resistance by regulating downstream signaling components, including transcription factors. Given the importance of AtMPK3 (and its orthologs) in both the priming (Beckers et al, 2009) and regulation of defense mechanisms against bacteria and fungi (Asai et al, 2002; Ren et al, 2008), a yeast two-hybrid screen was performed to find putative interactors of poplar PtiMPK3-1 This approach allowed the identification of a novel MAPK-interacting protein, PtiZFP1, a TF that belongs to the Cys-2/His-2type zinc finger protein family and that is characterized by the presence of an ERF-associated amphiphilic repression (EAR) motif at the C terminus. These results support a novel hypothesis in which MAPKs could serve as a molecular cue for the targeted degradation of EAR repressors and subsequent derepression of target genes

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