Z-REX uncovers a bifurcation in function of Keap1 paralogs
- École Polytechnique Fédérale de Lausanne, Switzerland
- Brigham and Women's Hospital, United States
- University of Utah, United States
- Xiamen University, China
- University of Sydney, Australia
- University of Lausanne, Switzerland
Abstract
Studying electrophile signaling is marred by difficulties in parsing changes in pathway flux attributable to on-target, vis-à-vis off-target, modifications. By combining bolus dosing, knockdown, and Z-REX-a tool investigating on-target/on-pathway electrophile signaling, we document that electrophile labeling of one zebrafish-Keap1-paralog (zKeap1b) stimulates Nrf2- driven antioxidant response (AR) signaling (like the human-ortholog). Conversely, zKeap1a is a dominant-negative regulator of electrophile-promoted Nrf2-signaling, and itself is nonpermissive for electrophile-induced Nrf2-upregulation. This behavior is recapitulated in human cells, wherein following electrophile treatment: (1) zKeap1b-transfected cells are permissive for augmented AR-signaling through reduced zKeap1b-Nrf2 binding; (2) zKeap1a-transfected cells are non-permissive for AR-upregulation, as zKeap1a-Nrf2 binding capacity remains unaltered; (3) 1:1 ZKeap1a:zKeap1b-transfected cells show no Nrf2-release from the Keap1-complex, rendering these cells unable to upregulate AR. We identified a zKeap1a-specific point-mutation (C273I) responsible for zKeap1a's behavior. Human-Keap1(C273I), of known diminished Nrf2-regulatory capacity, dominantly muted electrophile-induced Nrf2-signaling. These studies highlight divergent and interdependent electrophile signaling behaviors, despite conserved electrophile sensing.
Data availability
The data generated in this study using these materials are provided in Main Figure 1-8, accompanied by 17 associated Figure Supplements, and the Source Data Files associated with Main Figure 1-8 and 17 associated Figure Supplements.
Article and author information
Author details
Alexandra Van Hall-Beauvais
Funding
Novartis FreeNovation
- Yimon Aye
European Research Council
- Yimon Aye
Swiss Federal Institute od Technology
- Yimon Aye
National Institutes of Health (NIH T32GM008500)
- Jesse R Poganik
AHA predoctoral Fellowship (17PRE33670395)
- Jesse R Poganik
HHMI International Fellow
- Saba Parvez
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All procedures performed at Cornell (2017-2018) and EPFL (2018-present) conform to the animal care, maintenance, and experimentation procedures followed by Cornell University's and EPFL's Institutional Animal Care and Use Committee (IACUC) guidelines and approved by the respective institutional committees. All experiments with zebrafish performed at EPFL (2018-present) have been performed in accordance with the Swiss regulations on Animal Experimentation (Animal Welfare Act SR 455 and Animal Welfare Ordinance SR 455.1), in the EPFL zebrafish unit, cantonal veterinary authorization VD-H23).
Copyright
© 2022, Van Hall-Beauvais et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Z-REX uncovers a bifurcation in function of Keap1 paralogs
eLife 11:e83373.
https://doi.org/10.7554/eLife.83373
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