The mitochondrial Hsp70 chaperone Ssq1 facilitates Fe/S cluster transfer from Isu1 to Grx5 by complex formation
| Autor: | Sven-Andreas Freibert, Marta A. Uzarska, Rafal Dutkiewicz, Roland Lill, Ulrich Mühlenhoff |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Scaffold protein
Iron-Sulfur Proteins Saccharomyces cerevisiae Proteins Immunoprecipitation Biosynthesis and Biodegradation Plasma protein binding Mitochondrial Proteins chemistry.chemical_compound Adenosine Triphosphate Cytosol Glutaredoxin HSP70 Heat-Shock Proteins Binding site Molecular Biology Glutaredoxins Binding Sites biology Cell Biology Articles Mitochondria Adenosine Diphosphate chemistry Biochemistry Chaperone (protein) Mutation biology.protein Biophysics Electrophoresis Polyacrylamide Gel Adenosine triphosphate Molecular Chaperones Protein Binding |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| Popis: | The monothiol glutaredoxin Grx5 is defined as a core member of mitochondrial Fe/S protein biogenesis. Grx5 undergoes a highly specific protein interaction with the dedicated Hsp70 chaperone Ssq1. The simultaneous presence of the scaffold protein Isu1 and Grx5 on Ssq1 facilitates the transfer of newly synthesized Fe/S clusters from Isu1 to Grx5. The mitochondrial Hsp70 chaperone Ssq1 plays a dedicated role in the maturation of iron–sulfur (Fe/S) proteins, an essential process of mitochondria. Similar to its bacterial orthologue HscA, Ssq1 binds to the scaffold protein Isu1, thereby facilitating dissociation of the newly synthesized Fe/S cluster on Isu1 and its transfer to target apoproteins. Here we use in vivo and in vitro approaches to show that Ssq1 also interacts with the monothiol glutaredoxin 5 (Grx5) at a binding site different from that of Isu1. Grx5 binding does not stimulate the ATPase activity of Ssq1 and is most pronounced for the ADP-bound form of Ssq1, which interacts with Isu1 most tightly. The vicinity of Isu1 and Grx5 on the Hsp70 chaperone facilitates rapid Fe/S cluster transfer from Isu1 to Grx5. Grx5 and its bound Fe/S cluster are required for maturation of all cellular Fe/S proteins, regardless of the type of bound Fe/S cofactor and subcellular localization. Hence Grx5 functions as a late-acting component of the core Fe/S cluster (ISC) assembly machinery linking the Fe/S cluster synthesis reaction on Isu1 with late assembly steps involving Fe/S cluster targeting to dedicated apoproteins. |
| Databáze: | OpenAIRE |
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