The mitochondrial monothiol glutaredoxin S15 is essential for iron-sulfur protein maturation in Arabidopsis thaliana.
The iron-sulfur cluster (ISC) is an ancient and essential cofactor of many proteins involved in electron transfer and metabolic reactions. In Arabidopsis, three pathways exist for the maturation of iron-sulfur proteins in the cytosol, plastids, and mitochondria. We functionally characterized the role of mitochondrial glutaredoxin S15 (GRXS15) in biogenesis of ISC containing aconitase through a combination of genetic, physiological, and biochemical approaches. Two Arabidopsis T-DNA insertion mutants were identified as null mutants with early embryonic lethal phenotypes that could be rescued by GRXS15. Furthermore, we showed that recombinant GRXS15 is able to coordinate and transfer an ISC and that this coordination depends on reduced glutathione (GSH). We found the Arabidopsis GRXS15 able to complement growth defects based on disturbed ISC protein assembly of a yeast Δgrx5 mutant. Modeling of GRXS15 onto the crystal structures of related nonplant proteins highlighted amino acid residues that after mutation diminished GSH and subsequently ISC coordination, as well as the ability to rescue the yeast mutant. When used for plant complementation, one of these mutant variants, GRXS15K83/A, led to severe developmental delay and a pronounced decrease in aconitase activity by approximately 65%. These results indicate that mitochondrial GRXS15 is an essential protein in Arabidopsis, required for full activity of iron-sulfur proteins.
Institute of Crop Science and Resource Conservation (INRES)-Chemical Signalling, University of Bonn, 53113 Bonn, Germany;
Anna
A
Moseler
Institute of Crop Science and Resource Conservation (INRES)-Chemical Signalling, University of Bonn, 53113 Bonn, Germany;
Isabel
I
Aller
INRES-Plant Energy Biology, University of Bonn, 53113 Bonn, Germany;
Stephan
S
Wagner
INRES-Plant Energy Biology, University of Bonn, 53113 Bonn, Germany;
Thomas
T
Nietzel
Unité Mixte de Recherche (UMR) 1136 Interactions Arbres/Microorganismes, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; UMR 1136 Interactions Arbres/Microorganismes, Centre Institut National de la Recherche Agronomique (INRA) Nancy Lorraine, INRA, 54280 Champenoux, France;
Jonathan
J
Przybyla-Toscano
Institut für Zytobiologie, Philipps-Universität Marburg, 35032 Marburg, Germany;
Ulrich
U
Mühlenhoff
Institut für Zytobiologie, Philipps-Universität Marburg, 35032 Marburg, Germany;
Roland
R
Lill
Department of Neurology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany;
Carsten
C
Berndt
Unité Mixte de Recherche (UMR) 1136 Interactions Arbres/Microorganismes, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; UMR 1136 Interactions Arbres/Microorganismes, Centre Institut National de la Recherche Agronomique (INRA) Nancy Lorraine, INRA, 54280 Champenoux, France; Institut für Zytobiologie, Philipps-Universität Marburg, 35032 Marburg, Germany;
Nicolas
N
Rouhier
INRES-Plant Energy Biology, University of Bonn, 53113 Bonn, Germany;
Markus
M
Schwarzländer
Institute of Crop Science and Resource Conservation (INRES)-Chemical Signalling, University of Bonn, 53113 Bonn, Germany; Bioeconomy Science Center, c/o Forschungszentrum Jülich, 52425 Jülich, Germany andreas.meyer@uni-bonn.de.
Andreas J
AJ
Meyer
D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D005816:Genetic Complementation Test; D054477:Glutaredoxins / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*
D054477:Glutaredoxins; D007506:Iron-Sulfur Proteins
aconitase; glutaredoxin; glutathione; iron-sulfur cluster; mitochondria