Oxidation and phosphorylation of MAP kinase 4 cause protein aggregation

Mitogen-activated protein kinase (MPK) cascades are highly conserved signaling pathways that respond to environmental cues. Arabidopsis MPK4 has been identified as a stress-responsive protein kinase. Here we demonstrate that Brassica napus MPK4 (BnMPK4) is activated by hydrogen peroxide (H2O2) and p...

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Published in:Biochimica et biophysica acta 2015-02, Vol.1854 (2), p.156-165
Main Authors: Zhang, Tong, Zhu, Mengmeng, Song, Wen-yuan, Harmon, Alice C., Chen, Sixue
Format: Article
Language:English
Subjects:
Abscisic Acid - pharmacology
Arabidopsis
Arabidopsis Proteins - genetics
Arabidopsis Proteins - metabolism
Brassica napus
Brassica napus - drug effects
Brassica napus - enzymology
Gene Expression Regulation, Plant - drug effects
Hydrogen Peroxide - pharmacology
MAP kinase 4
Mitogen-Activated Protein Kinases - genetics
Mitogen-Activated Protein Kinases - metabolism
Nicotiana benthamiana
Oxidation-Reduction
Phosphorylation
Phosphorylation - drug effects
Protein Aggregates - genetics
Protein aggregation
Reactive Oxygen Species - metabolism
ROS
Signal Transduction - drug effects
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Summary:Mitogen-activated protein kinase (MPK) cascades are highly conserved signaling pathways that respond to environmental cues. Arabidopsis MPK4 has been identified as a stress-responsive protein kinase. Here we demonstrate that Brassica napus MPK4 (BnMPK4) is activated by hydrogen peroxide (H2O2) and phytohormone abscisic acid (ABA). Transient expression of a constitutively active BnMPK4 causes H2O2 production and cell death in Nicotiana benthamiana leaves. However, little is known about how H2O2 contributes to the regulation of MPK4 kinase function. Biochemical analysis revealed that recombinant BnMPK4 autophosphorylates on both threonine and tyrosine residues in the activation loop. In the presence of H2O2, phosphorylation of BnMPK4 caused protein aggregation in vitro. The aggregation of BnMPK4 could be reversed to the monomeric form by reducing reagents. Point-mutation of cysteine codons indicated that cysteine 232 is involved in protein aggregation. Our results suggest that BnMPK4 is involved in reactive oxygen species (ROS) signaling and metabolism, and its aggregation may be modulated by redox. [Display omitted] •MPK4 is activated by stress, and active MPK4 promotes ROS production.•MPK4 phosphorylation sites were mapped.•MPK4 autophosphorylation led to protein aggregation in the presence of H2O2in vitro.
ISSN:1570-9639
0006-3002
1878-1454
1878-2434
DOI:10.1016/j.bbapap.2014.11.006