ABSTRACT
NEET proteins are conserved 2Fe-2S proteins that regulate the levels of iron and reactive oxygen species in plant and mammalian cells. Previous studies of seedlings with constitutive expression of AtNEET, or its dominant-negative variant H89C (impaired in 2Fe-2S cluster transfer), revealed that disrupting AtNEET function causes oxidative stress, chloroplast iron overload, activation of iron-deficiency responses, and cell death. Because disrupting AtNEET function is deleterious to plants, we developed an inducible expression system to study AtNEET function in mature plants using a time-course proteomics approach. Here, we report that suppression of AtNEET cluster transfer function results in drastic changes in the expression of different members of the ferredoxin (Fd), Fd-thioredoxin (TRX) reductase (FTR), and TRX network of Arabidopsis, as well as in cytosolic cluster assembly proteins. In addition, the expression of Yellow Stripe-Like 6 (YSL6), involved in iron export from chloroplasts was elevated. Taken together, our findings reveal new roles for AtNEET in supporting the Fd-TFR-TRX network of plants, iron mobilization from the chloroplast, and cytosolic 2Fe-2S cluster assembly. In addition, we show that AtNEET function is linked to the expression of glutathione peroxidases (GPXs) which play a key role in the regulation of ferroptosis and redox balance in different organisms.
Highlight Using proteomics analysis and an inducible expression system, the iron-sulfur cluster transfer function of AtNEET was found to support the ferredoxin-thioredoxin network of Arabidopsis.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Email addresses: sizquier{at}uji.es (SIZ); luhuas2010{at}gmail.com (LS); rachel{at}mail.huji.ac.il (RN); mendozad{at}missouri.edu (DGM-C); mittlerr{at}missouri.edu (RM).
Abbreviations
- CIA
- cytosolic iron-sulfur cluster assembly
- CISD
- CDGSH Iron-Sulfur Domain
- DEX
- dexamethasone
- Fd
- ferredoxin
- FTR
- ferredoxin:thioredoxin reductase
- GSH
- glutathione;
- GPX
- glutathione peroxidase
- GR
- glutathione reductase
- MDAR
- monodehydroascorbate reductase
- MS
- mass spectrometry
- ROS
- reactive oxygen species
- TRX
- thioredoxin
- TXNIP
- thioredoxin interacting protein