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J Biol Chem. 2016 Apr 1;291(14):7583-93. doi: 10.1074/jbc.M115.711218. Epub 2016 Feb 17.

Redox Control of the Human Iron-Sulfur Repair Protein MitoNEET Activity via Its Iron-Sulfur Cluster.

Author information

1
From the Institut de Chimie des Substances Naturelles (ICSN), CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, 91190 Gif-sur-Yvette, France, marie-pierre.golinelli@cnrs.fr.
2
From the Institut de Chimie des Substances Naturelles (ICSN), CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, 91190 Gif-sur-Yvette, France.
3
Université Grenoble Alpes, Laboratoire Chimie et Biologie des Métaux (LCBM), and Commissariat à l'Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), Institut de Recherche en Technologies et Sciences pour le Vivant (iRTSV), LCBM, Equipe Physicochimie des Métaux en Biologie (PMB), and CNRS UMR 5249, LCBM, 38054 Grenoble, France, and.
4
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91190 Gif-sur-Yvette, France.
5
From the Institut de Chimie des Substances Naturelles (ICSN), CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, 91190 Gif-sur-Yvette, France, cecile.bouton@cnrs.fr.

Abstract

Human mitoNEET (mNT) is the first identified Fe-S protein of the mammalian outer mitochondrial membrane. Recently, mNT has been implicated in cytosolic Fe-S repair of a key regulator of cellular iron homeostasis. Here, we aimed to decipher the mechanism by which mNT triggers its Fe-S repair capacity. By using tightly controlled reactions combined with complementary spectroscopic approaches, we have determined the differential roles played by both the redox state of the mNT cluster and dioxygen in cluster transfer and protein stability. We unambiguously demonstrated that only the oxidized state of the mNT cluster triggers cluster transfer to a generic acceptor protein and that dioxygen is neither required for the cluster transfer reaction nor does it affect the transfer rate. In the absence of apo-acceptors, a large fraction of the oxidized holo-mNT form is converted back to reduced holo-mNT under low oxygen tension. Reduced holo-mNT, which holds a [2Fe-2S](+)with a global protein fold similar to that of the oxidized form is, by contrast, resistant in losing its cluster or in transferring it. Our findings thus demonstrate that mNT uses an iron-based redox switch mechanism to regulate the transfer of its cluster. The oxidized state is the "active state," which reacts promptly to initiate Fe-S transfer independently of dioxygen, whereas the reduced state is a "dormant form." Finally, we propose that the redox-sensing function of mNT is a key component of the cellular adaptive response to help stress-sensitive Fe-S proteins recover from oxidative injury.

KEYWORDS:

Fe-S lability; Fe-S transfer; Mossbauer spectroscopy; Raman spectroscopy; iron-sulfur protein; mitoNEET; nuclear magnetic resonance (NMR); protein stability

PMID:
26887944
PMCID:
PMC4817186
DOI:
10.1074/jbc.M115.711218
[Indexed for MEDLINE]
Free PMC Article

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