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Measurements of Physiological Stress Responses in C. Elegans
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EXECUTER2 modulates the EXECUTER1 signalosome through its singlet oxygen-dependent oxidation
Vivek Dogra1, Rahul Mohan Singh1, Mengping Li2
1Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
Molecular Plant
|December 30, 2021
Summary
The EXECUTER2 (EX2) protein negatively regulates singlet oxygen (1O2) signaling in Arabidopsis thaliana by undergoing oxidation and degradation, thereby modulating EXECUTER1 (EX1) activity. This discovery reveals a new mechanism controlling plant stress responses.
Area of Science:
- Plant molecular biology
- Chloroplast signaling
- Reactive oxygen species metabolism
Background:
- Oxidative post-translational modifications initiate retrograde signaling.
- EXECUTER1 (EX1) is a chloroplast protein sensing singlet oxygen (1O2) via tryptophan (Trp) 643 oxidation, leading to EX1 degradation and signaling.
- 1O2 is a chloroplast-derived, light-dependent reactive oxygen species.
Purpose of the Study:
- To investigate the role of the EX1-like protein EX2 in 1O2 signaling.
- To elucidate the regulatory mechanism of EX1-mediated 1O2 signaling by EX2.
Main Methods:
- Analysis of 1O2-dependent tryptophan oxidation in EX2.
- Investigation of FtsH protease-dependent turnover of EX2.
- Phenotypic analysis of EX2 loss-of-function and overexpression mutants.
- Phylogenetic analysis of EX2 evolution.
Main Results:
- EX2 undergoes 1O2-dependent Trp530 oxidation and FtsH-dependent degradation.
- EX2 attenuates 1O2 signaling by slowing EX1 oxidation and degradation.
- Loss of EX2 function enhances EX1-dependent signaling, while EX2 overexpression has opposite effects.
- Phylogenetic analysis suggests EX2 evolved to modulate EX1 sensitivity to 1O2.
Conclusions:
- EX2 acts as a negative regulator of the EX1 signalosome.
- EX2's own 1O2-dependent oxidation and turnover provide feedback regulation.
- This study offers new insights into the control of EX1-mediated 1O2 signaling in plants.
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