Related Experiment Video
Updated: Jun 16, 2026
07:16
Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
Trp521 oxidation affects FtsH2 stability and its role in PSII repair
Jingzhi Zhang1,2, Keun Pyo Lee1, Yujie Lou2,3
1State Key Laboratory of Plant Trait Design, Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
The New Phytologist
|June 14, 2026
Summary
Oxidative modification of FtsH2, a key protease in chloroplasts, impacts its function in photosystem II (PSII) repair. This research reveals how redox-sensitive residues regulate PSII protein homeostasis and plant stress responses.
Area of Science:
- Plant Biology
- Molecular Biology
- Biochemistry
Background:
- Photosynthesis produces reactive oxygen species (ROS), causing damage to photosystem II (PSII).
- The D1 protein is a primary target of singlet oxygen (1O2) damage during photooxidative stress.
- FtsH metalloprotease complex degrades damaged D1 protein for PSII repair.
Purpose of the Study:
- To investigate the role of oxidative modification in FtsH complex function, particularly FtsH2.
- To elucidate the mechanism by which redox-sensitive residues in FtsH2 affect PSII repair and chloroplast protein homeostasis.
Main Methods:
- Utilized *Arabidopsis thaliana* as a model organism.
- Generated transgenic plants expressing FtsH2 variants with specific tryptophan residue substitutions.
- Analyzed FtsH2 stability, D1 degradation efficiency, and plant growth under various stress conditions.
Main Results:
- Identified a conserved, oxidation-prone tryptophan residue in type B FtsH isomers (FtsH2/8).
- Demonstrated that tryptophan oxidation in FtsH2 affects its stability and D1 degradation activity.
- Observed that oxidation-mimicking FtsH2 variants impair plant growth and survival, while oxidation-insensitive variants enhance PSII repair and growth.
Conclusions:
- Oxidative modification of FtsH2 is a critical regulatory mechanism influencing PSII repair efficiency.
- Redox-sensitive residues in FtsH2 play a key role in maintaining chloroplast protein homeostasis under stress.
- Findings provide mechanistic insights into the regulation of PSII repair and plant adaptation to photooxidative stress.
Related Concept Videos
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
01:19Translocation of Proteins into the Mitochondria
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
01:37The Unfolded Protein Response
The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...