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Arabidopsis E3 ligase KEG associates with and ubiquitinates MKK4 and MKK5 to regulate plant immunity
- Source :
- Journal of Integrative Plant Biology. 63:327-339
- Publication Year :
- 2020
- Publisher :
- Wiley, 2020.
-
Abstract
- Mitogen-activated protein kinase (MAPK) cascades are highly conserved signaling modules that regulate plant immune responses. The Arabidopsis thaliana Raf-like MAPK kinase kinase ENHANCED DISEASE RESISTANCE1 (EDR1) is a key negative regulator of plant immunity that affects the protein levels of MKK4 and MKK5, two important MAPK cascade members, but the underlying mechanism is poorly understood. Here, genome-wide phosphorylation analysis demonstrated that the E3 ligase KEEP ON GOING (KEG) is phosphorylated in the edr1 mutant but not the wild type, suggesting that EDR1 negatively affects KEG phosphorylation. The identified phosphorylation sites in KEG appear to be important for its accumulation. The keg-4 mutant, a previously identified edr1 suppressor, enhances susceptibility to the powdery mildew pathogen Golovinomyces cichoracearum. In addition, MKK4 and MKK5 protein levels are reduced in the keg-4 mutant. Furthermore, we demonstrate that MKK4 and MKK5 associate with full-length KEG, but not with truncated KEG-RK or KEG-RKA, and that KEG ubiquitinates and mediates the degradation of MKK4 and MKK5. Taken together, these results indicate that MKK4 and MKK5 protein levels are regulated by KEG via ubiquitination, uncovering a mechanism by which plants fine-tune immune responses by regulating the homeostasis of key MAPK cascade members via ubiquitination and degradation.
- Subjects :
- 0106 biological sciences
0301 basic medicine
MAPK/ERK pathway
Ubiquitin-Protein Ligases
Green Fluorescent Proteins
Arabidopsis
Plant Science
MAPK cascade
Models, Biological
01 natural sciences
Biochemistry
General Biochemistry, Genetics and Molecular Biology
03 medical and health sciences
Ascomycota
Arabidopsis thaliana
Plant Immunity
Amino Acid Sequence
Phosphorylation
Protein kinase A
Plant Diseases
Mitogen-Activated Protein Kinase Kinases
biology
Arabidopsis Proteins
Kinase
Ubiquitination
biology.organism_classification
Ubiquitin ligase
Cell biology
030104 developmental biology
Mutation
biology.protein
Protein Binding
010606 plant biology & botany
Subjects
Details
- ISSN :
- 17447909 and 16729072
- Volume :
- 63
- Database :
- OpenAIRE
- Journal :
- Journal of Integrative Plant Biology
- Accession number :
- edsair.doi.dedup.....5976a0621b4da4e71924f2664d460ef4