1. Glutaredoxin GRXS17 Associates with the Cytosolic Iron-Sulfur Cluster Assembly Pathway.
- Author
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Iñigo S, Durand AN, Ritter A, Le Gall S, Termathe M, Klassen R, Tohge T, De Coninck B, Van Leene J, De Clercq R, Cammue BP, Fernie AR, Gevaert K, De Jaeger G, Leidel SA, Schaffrath R, Van Lijsebettens M, Pauwels L, and Goossens A
- Subjects
- Arabidopsis genetics, Arabidopsis metabolism, Arabidopsis Proteins genetics, DNA Damage, Gene Expression Regulation, Plant, Glutaredoxins genetics, Immunoblotting, Mutation, Plant Leaves genetics, Plant Leaves metabolism, Plant Roots genetics, Plant Roots metabolism, Plants, Genetically Modified, Protein Binding, Reverse Transcriptase Polymerase Chain Reaction, Xanthine Dehydrogenase genetics, Xanthine Dehydrogenase metabolism, Arabidopsis Proteins metabolism, Biosynthetic Pathways, Cytosol metabolism, Glutaredoxins metabolism, Iron-Sulfur Proteins metabolism
- Abstract
Cytosolic monothiol glutaredoxins (GRXs) are required in iron-sulfur (Fe-S) cluster delivery and iron sensing in yeast and mammals. In plants, it is unclear whether they have similar functions. Arabidopsis (Arabidopsis thaliana) has a sole class II cytosolic monothiol GRX encoded by GRXS17 Here, we used tandem affinity purification to establish that Arabidopsis GRXS17 associates with most known cytosolic Fe-S assembly (CIA) components. Similar to mutant plants with defective CIA components, grxs17 loss-of-function mutants showed some degree of hypersensitivity to DNA damage and elevated expression of DNA damage marker genes. We also found that several putative Fe-S client proteins directly bind to GRXS17, such as XANTHINE DEHYDROGENASE1 (XDH1), involved in the purine salvage pathway, and CYTOSOLIC THIOURIDYLASE SUBUNIT1 and CYTOSOLIC THIOURIDYLASE SUBUNIT2, both essential for the 2-thiolation step of 5-methoxycarbonylmethyl-2-thiouridine (mcm
5 s2 U) modification of tRNAs. Correspondingly, profiling of the grxs17-1 mutant pointed to a perturbed flux through the purine degradation pathway and revealed that it phenocopied mutants in the elongator subunit ELO3, essential for the mcm5 tRNA modification step, although we did not find XDH1 activity or tRNA thiolation to be markedly reduced in the grxs17-1 mutant. Taken together, our data suggest that plant cytosolic monothiol GRXs associate with the CIA complex, as in other eukaryotes, and contribute to, but are not essential for, the correct functioning of client Fe-S proteins in unchallenged conditions., (© 2016 American Society of Plant Biologists. All Rights Reserved.)- Published
- 2016
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