Related Experiment Video
Updated: Mar 31, 2026
Ubiquitin Chain Analysis by Parallel Reaction Monitoring
Published on: June 17, 2020
Identification of an unstable 4-hydroxynoneal modification on the 20S proteasome subunit α7 by recombinant antibody
Jesper Just1, Tobias Jung2, Niels Anton Friis1
1Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10, 8000 Aarhus C, Denmark.
Abstract:
Numerous cellular functions rely on an active proteasome allowing degradation of damaged or misfolded proteins. Therefore changes in the proteasomal activity have important physiological consequences. During oxidative stress the production of free radicals can result in the formation of 4-hydroxynonenal (HNE) following lipid peroxidiation. The HNE moiety is highly reactive and via a nucleophilic attack readily forms covalent links to cysteine, histidine and lysine side chains. However, as the chemical properties of these amino acids differ, so does the kinetics of the reactions. While covalent linkage through Michael addition is well established, reversible and unstable associations have only been indicated in a few cases. In the present study we have identified an unstable HNE adduct on the α7 subunit of the 20S proteasome using phage display of recombinant antibodies. This recombinant antibody fragment recognized HNE modified proteasomes in vitro and showed that this epitope was easily HNE modified, yet unstable, and influenced by experimental procedures. Hence unstable HNE-adducts could be overlooked as a regulatory mechanism of proteasomal activity and a participating factor in the decreased proteasomal activity associated with oxidative stress.
Insights
Oxidative stress can cause unstable 4-hydroxynonenal (HNE) adducts on proteasomes, potentially impacting proteasomal activity and cellular functions. These transient modifications may be overlooked in studies of oxidative stress.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Proteasome activity is crucial for degrading damaged proteins and maintaining cellular homeostasis.
- Oxidative stress generates reactive aldehydes like 4-hydroxynonenal (HNE) from lipid peroxidation.
- HNE can modify proteins, but the nature and stability of these adducts are not fully understood.
Purpose of the Study:
- To investigate the formation and characteristics of 4-hydroxynonenal (HNE) adducts on the 20S proteasome.
- To determine if HNE adducts can represent a regulatory mechanism for proteasomal activity.
Main Methods:
- Utilized phage display technology to generate recombinant antibodies against HNE-modified proteasomes.
- Employed in vitro assays to characterize the HNE epitope on the α7 subunit of the 20S proteasome.
Main Results:
- Identified an unstable HNE adduct on the α7 subunit of the 20S proteasome.
- Demonstrated that this HNE epitope is readily formed but sensitive to experimental conditions.
- The antibody fragment recognized HNE-modified proteasomes, confirming the adduct's presence.
Conclusions:
- Unstable HNE adducts on the proteasome may represent a previously overlooked regulatory mechanism.
- These transient modifications could contribute to the observed decrease in proteasomal activity during oxidative stress.
- Further research is needed to fully elucidate the role of unstable HNE adducts in cellular regulation.
More Related Videos
08:12Utilizing a Comprehensive Immunoprecipitation Enrichment System to Identify an Endogenous Post-translational Modification Profile for Target Proteins
Published on: January 8, 2018
11:54Detection of Protein Ubiquitination Sites by Peptide Enrichment and Mass Spectrometry
Published on: March 23, 2020
Related Concept Videos
01:13The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
01:17The Proteasome Structure
The proteasome is an...