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Regulation of Iron Metabolism by [2Fe‐2S]‐Binding Glutaredoxins
Author(s) -
Outten Caryn E.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.477.2
Subject(s) - glutaredoxin , saccharomyces cerevisiae , chemistry , yeast , biochemistry , iron–sulfur cluster , transcription factor , microbiology and biotechnology , biophysics , biology , glutathione , gene , enzyme
Disruptions in iron metabolism have been implicated in human diseases such as iron overload disorders, neurodegenerative diseases, and mitochondrial dysfunction disorders. To better understand iron regulation at the cellular and molecular level, our research group is teasing out the mechanistic details of iron sensing and regulation in the model eukaryotes S. cerevisiae and S. pombe . Our studies are focused on characterizing the monothiol glutaredoxins Grx3 and Grx4 that utilize glutathione to bind [2Fe‐2S] 2+ clusters and regulate the function of transcription factors that control iron uptake, storage, and utilization genes. Using a combination of protein biochemistry, spectroscopy, mutagenesis, and yeast genetics and cell biology we have demonstrated that Fe‐S clusters play a key role in signaling iron bioavailability in both budding and fission yeast (1–3). In S. cerevisiae , Grx3 and Grx4 interact specifically with the low iron sensing transcriptional activators Aft1 and Aft2, transferring an Fe‐S cluster to Aft1/2 that inhibits its DNA binding activity. To define the mechanistic details of complex formation and Fe‐S transfer between Grx3, Fra2, and Aft2, we are probing the kinetics and thermodynamics of these reactions and identifying which residues in Fra2, Grx3, and Aft2 play key roles in donor‐target recognition and/or Fe‐S cluster transfer. Our findings demonstrate that substitution of the Fra2 cluster ligands His103 and Cys66 have specific and differential effects on the transfer reaction. Furthermore, we have identified the Fe‐S binding ligands in Aft2 and their individual roles in the transfer process. Overall, these studies provide a detailed picture of the dynamic interactions between these Fe‐S binding partners that govern iron regulation in yeast and higher eukaryotes. Support or Funding Information This research was supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM118164.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .