Abstract
Frataxin is an essential mitochondrial protein whose reduced expression causes Friedreich's ataxia (FRDA), a lethal neurodegenerative disease. It is believed that frataxin is an iron chaperone that participates in iron metabolism. We have tested this hypothesis using the bacterial frataxin ortholog, CyaY, and different biochemical and biophysical techniques. We observe that CyaY participates in iron-sulfur (Fe-S) cluster assembly as an iron-dependent inhibitor of cluster formation, through binding to the desulfurase IscS. The interaction with IscS involves the iron binding surface of CyaY, which is conserved throughout the frataxin family. We propose that frataxins are iron sensors that act as regulators of Fe-S cluster formation to fine-tune the quantity of Fe-S cluster formed to the concentration of the available acceptors. Our observations provide new perspectives for understanding FRDA and a mechanistic model that rationalizes the available knowledge on frataxin.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$189.00 per year
only $15.75 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Pandolfo, M. Iron and Friedreich's ataxia. J. Neural Transm. Suppl. 70, 143–146 (2006).
Campuzano, V. et al. Friedreich's ataxia: autosomal recessive disease caused by an intronic GAA triplet repeat expansion. Science 271, 1423–1427 (1996).
Koutnikova, H. et al. Studies of human, mouse and yeast homologues indicate a mitochondrial function for frataxin. Nat. Genet. 16, 345–351 (1997).
Adinolfi, S., Trifuoggi, M., Politou, A.S., Martin, S. & Pastore, A. A structural approach to understanding the iron-binding properties of phylogenetically different frataxins. Hum. Mol. Genet. 11, 1865–1877 (2002).
He, Y. et al. Yeast frataxin solution structure, iron binding & ferrochelatase interaction. Biochemistry 43, 16254–16262 (2004).
Nair, M. et al. Solution structure of the bacterial frataxin ortholog, CyaY: mapping the iron binding sites. Structure 12, 2037–2048 (2004).
Cook, J.D. et al. Monomeric yeast frataxin is an iron-binding protein. Biochemistry 45, 7767–7777 (2006).
Foury, F. & Cazzalini, O. Deletion of the yeast homologue of the human gene associated with Friedreich's ataxia elicits iron accumulation in mitochondria. FEBS Lett. 411, 373–377 (1997).
Lesuisse, E. et al. Iron use for haeme synthesis is under control of the yeast frataxin homologue (Yfh1). Hum. Mol. Genet. 12, 879–889 (2003).
Yoon, T. & Cowan, J.P. Frataxin-mediated iron delivery to ferrochelatase in the final step of heme biosynthesis. J. Biol. Chem. 279, 25943–25946 (2004).
Gerber, J., Muhlenhoff, U. & Lill, R. An interaction between frataxin and Isu1/Nfs1 that is crucial for Fe/S cluster synthesis on Isu1. EMBO Rep. 4, 906–911 (2003).
Ramazzotti, A., Vanmansart, V. & Foury, F. Mitochondrial functional interactions between frataxin and Isu1p, the iron-sulfur cluster scaffold protein, in Saccharomyces cerevisiae. FEBS Lett. 557, 215–220 (2004).
Layer, G., Ollagnier-de Choudens, S., Sanakis, Y. & Fontecave, M. Iron-sulfur cluster biosynthesis: characterization of Escherichia coli CYaY as an iron donor for the assembly of [2Fe-2S] clusters in the scaffold IscU. J. Biol. Chem. 281, 16256–16263 (2006).
Yoon, T. & Cowan, J.A. Iron-sulfur cluster biosynthesis characterization of frataxin as an iron donor for assembly of [2Fe-2S] clusters in ISU-type proteins. J. Am. Chem. Soc. 125, 6078–6084 (2003).
Adamec, J. et al. Iron-dependent self-assembly of recombinant yeast frataxin: implications for Friedreich ataxia. Am. J. Hum. Genet. 67, 549–562 (2000).
Johnson, D.C., Dean, D.R., Smith, A.D. & Johnson, M.K. Structure, function, and formation of biological iron-sulfur clusters. Annu. Rev. Biochem. 74, 247–281 (2005).
Nuth, M., Yoon, T. & Cowan, J.A. Iron-sulfur cluster biosynthesis: characterization of iron nucleation sites for assembly of the [2Fe-2S]2+ cluster core in IscU proteins. J. Am. Chem. Soc. 124, 8774–8775 (2002).
Agar, J.N., Krebs, C., Frazzon, J., Hanh Huynh, B. & Dean, D.R. IscU as a scaffold for iron-sulfur cluster biosynthesis: sequential assembly of [2Fe-2S] and [4Fe-4S] clusters in IscU. Biochemistry 39, 7856–7862 (2000).
Yuvaniyama, P., Agar, J.N., Cash, V.L., Johnson, M.K. & Dean, D.R. NifS-directed assembly of a transient [2Fe-2S] cluster within the NifU protein. Proc. Natl. Acad. Sci. USA 97, 599–604 (2000).
Urbina, H.D., Silberg, J.J., Hoff, K.G. & Vickery, L.E. Transfer of sulfur from IscS to IscU during Fe/S cluster assembly. J. Biol. Chem. 276, 44521–44526 (2001).
Mansy, S.S. Wu, G., Surerus, K.K. & Cowan, J.A. Iron-sulfur cluster biosynthesis. Thermatoga maritima IscU is a structured iron-sulfur cluster assembly protein. J. Biol. Chem. 277, 21397–21404 (2002).
Bou-Abdallah, F., Adinolfi, S., Pastore, A., Laue, T.M. & Chasteen, D.N. Iron binding & oxidation kinetics in frataxin CyaY of Escherichia coli. J. Mol. Biol. 341, 605–615 (2004).
Bonomi, F., Pagani, S. & Kurtz, D.M. Jr. Enzymatic synthesis of the 4Fe-4S clusters of Clostridium pasteurianum ferredoxin. Eur. J. Biochem. 148, 67–73 (1985).
Bonomi, F., Iametti, S., Ta, D. & Vickery, L.E. Multiple turnover transfer of [2Fe2S] clusters by the iron-sulfur cluster assembly scaffold proteins IscU and IscA. J. Biol. Chem. 280, 29513–29518 (2005).
Musco, G. et al. Towards a structural understanding of Friedreich's ataxia: the solution structure of frataxin. Structure 8, 695–707 (2000).
Pastore, C., Franzese, M., Sica, F., Temussi, P. & Pastore, A. Understanding the binding properties of an unusual metal binding protein: a study of bacterial frataxin. FEBS J. 274, 4199–4210 (2007).
Foury, F., Pastore, A. & Trincal, M. Acidic residues of yeast frataxin have an essential role in Fe-S cluster assembly. EMBO Rep. 8, 194–199 (2007).
Labuda, M., Poirier, J. & Pandolfo, M. A missense mutation (W155R) in an American patient with Friedreich Ataxia. Hum. Mutat. 13, 506–509 (1999).
Correia, A.R., Adinolfi, S., Pastore, A. & Gomes, C. Conformational stability of human frataxin and effect of Friedreich's ataxia related mutations on protein folding. Biochem. J. 398, 605–611 (2006).
Bedekovics, T., Gajdos, G.B., Kispal, G. & Isaya, G. Partial conservation of functions between eukaryotic frataxin and the Escherichia coli frataxin homolog CyaY. FEMS Yeast Res. 7, 1276–1284 (2007).
Cavadini, P., Gellera, C., Patel, P.I. & Isaya, G. Human frataxin maintains mitochondrial iron homeostasis in Saccharomyces cerevisiae. Hum. Mol. Genet. 9, 2523–2530 (2000).
Huang, J., Dizin, E. & Cowan, J.A. Mapping iron binding sites on human frataxin: implications for cluster assembly on the ISU Fe-S cluster scaffold protein. J. Biol. Inorg. Chem. 13, 825–836 (2008).
Schwartz, C.J. et al. IscR, an Fe-S cluster-containing transcription factor, represses expression of Escherichia coli genes encoding Fe-S cluster assembly proteins. Proc. Natl. Acad. Sci. USA 98, 14895–14900 (2001).
Cossee, M. et al. Inactivation of the Friedreich ataxia mouse gene leads to early embryonic lethality without iron accumulation. Hum. Mol. Genet. 9, 1219–1226 (2000).
Leidgens, S. The function of yeast frataxin in iron-sulfur cluster biogenesis: a systematic mutagenesis of the solvent-exposed side chains of the beta-sheet platform. PhD thesis Louvain la Neuf (Belgium) (2008).
Levi, S. et al. A human mitochondrial ferritin encoded by an intronless gene. J. Biol. Chem. 276, 24437–24440 (2001).
Aloria, K., Schilke, B., Andrew, A. & Craig, E.A. Iron-induced oligomerization of yeast frataxin homologue Yfh1 is dispensable in vivo. EMBO Rep. 5, 1096–1101 (2004).
Acknowledgements
We dedicate this work to the memory of Margie Nair. We are thankful to R.A.G. Williams, F. Foury, M. Pandolfo and H. Puccio for stimulating discussions, P. Temussi for moral support, L. Temussi for technical discussions and the Mill Hill NMR Centre for technical support. The project was supported by PUR funds (F.B. and S.I., University of Milan).
Author information
Authors and Affiliations
Corresponding author
Supplementary information
Supplementary Text and Figures
Supplementary Figures 1 and 2 and Supplementary Methods (PDF 282 kb)
Rights and permissions
About this article
Cite this article
Adinolfi, S., Iannuzzi, C., Prischi, F. et al. Bacterial frataxin CyaY is the gatekeeper of iron-sulfur cluster formation catalyzed by IscS. Nat Struct Mol Biol 16, 390–396 (2009). https://doi.org/10.1038/nsmb.1579
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nsmb.1579
This article is cited by
-
Description and genomic characterization of Gallaecimonas kandeliae sp. nov., isolated from the sediments of mangrove plant Kandelia obovate
Antonie van Leeuwenhoek (2023)
-
Physiologically relevant reconstitution of iron-sulfur cluster biosynthesis uncovers persulfide-processing functions of ferredoxin-2 and frataxin
Nature Communications (2019)
-
Backbone resonance assignments and secondary structure of the apo-Drosophila melanogaster frataxin homolog (Dfh)
Biomolecular NMR Assignments (2019)
-
Assessment of cell-free levels of iron and copper in patients with Friedreich’s ataxia
BioMetals (2019)
-
The cold denaturation of IscU highlights structure–function dualism in marginally stable proteins
Communications Chemistry (2018)