Mammalian Fe–S proteins: definition of a consensus motif recognized by the co-chaperone HSC20

Maio, Nunziata; Rouault, Tracey A.

doi:10.1039/c6mt00167j

Cited by 31 publications

(40 citation statements)

References 172 publications

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“…Likewise, the mutant protein is unable to receive a [2Fe-2S] cluster from typical iron-sulfur scaffold proteins such as Isa1 and IscU (Table 5), which have been shown to deliver a cluster into native NFU1 [10, 14]. Current models for Fe/S cluster biogenesis indicate that transfer from IscU is promoted with assistance from heat shock chaperone proteins [16, 37, 47, 55]. We have found that transfer from holo IscU to apo native NFU1 or G208C NFU1 does not occur in the presence of the chaperones (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…5B), indicating that human IscU is incapable of transferring cluster into G208C NFU1 (data not shown). Because involvement by Hsc co-chaperones has been implicated in IscU-promoted cluster delivery to target proteins [16, 37, 47], we also examined the kinetics of transfer from holo human IscU to apo human NFU1 and G208C NFU1 in the presence of HSPA9, Hsc20, MgCl 2 and ATP. With the chaperones, IscU was unable to transfer cluster in to either the native or the mutant (Fig.…”

Section: Functional Impairment Of G208c Nfu1mentioning

confidence: 99%

“…The thermodynamic stability of NFU1 has been studied in depth to reveal that the isolated C-terminal domain of human NFU1 exhibits characteristics of a molten globular state [4, 30], while the isolated N-terminal domain demonstrates a highly ordered structure. However, when the two domains come together the overall protein maintains a relatively well-folded structure, suggesting a requirement for the unique N-terminal domain of the human protein to provide structural stabilization as well as serving a potential functional role [4, 30] that may include a protein oligomerization surface or a binding site for chaperones, such as Hsc20 [5, 37]. Structure-function characteristics of human NFU1 remain unclear, because this protein has been implicated in a variety of cellular roles.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the Molecular Basis of Multiple Mitochondrial Dysfunctions Syndrome 1 (MMDS1)—Impact of a Disease-Causing Gly208Cys Substitution on Structure and Activity of NFU1 in the Fe/S Cluster Biosynthetic Pathway

Wachnowsky

Wesley

Fidai

et al. 2017

Journal of Molecular Biology

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Iron-sulfur (Fe/S) cluster-containing proteins constitute one of the largest protein classes, with varied functions that include electron transport, regulation of gene expression, substrate binding and activation, and radical generation. Consequently, the biosynthetic machinery for Fe/S clusters is evolutionarily conserved, and mutations in a variety of putative intermediate Fe/S cluster scaffold proteins can cause disease states, including multiple mitochondrial dysfunctions syndrome (MMDS), sideroblastic anemia and mitochondrial encephalomyopathy. Herein, we have characterized the impact of defects occurring in the MMDS1 disease state that result from a point mutation (Gly208Cys) near the active site of NFU1, an iron-sulfur scaffold protein, via an in vitro investigation into the structural and functional consequences. Analysis of protein stability and oligomeric state demonstrates that the mutant increases the propensity to dimerize and perturbs the secondary structure composition. These changes appear to underlie the severely decreased ability of mutant NFU1 to accept an iron-sulfur cluster from physiologically relevant sources. Therefore, the point mutation on NFU1 impairs downstream cluster trafficking and results in the disease phenotype, because there does not appear to be an alternative in vivo reconstitution path, most likely due to greater protein oligomerization from a minor structural change.

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Section: Discussionmentioning

confidence: 99%

Section: Functional Impairment Of G208c Nfu1mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Understanding the Molecular Basis of Multiple Mitochondrial Dysfunctions Syndrome 1 (MMDS1)—Impact of a Disease-Causing Gly208Cys Substitution on Structure and Activity of NFU1 in the Fe/S Cluster Biosynthetic Pathway

Wachnowsky

Wesley

Fidai

et al. 2017

Journal of Molecular Biology

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“…In addition, some Fe-S clusters are deeply buried within proteins, suggesting that they must be inserted during folding, and in some cases, they may contribute to the tertiary structure of the protein, by drawing distal cysteine residues into proximity (75,76).…”

Section: How Are Fe-s Clusters Delivered To Correct Recipient Proteins?mentioning

confidence: 99%

“…If Fe-S proteins prove to be fairly abundant, it would affect the calculations about cysteines, disulfide bonds, and redox status, as many cysteines would be engaged in ligating Fe-S cofactors (98). Bioinformatics approaches can foster identification of candidate Fe-S proteins, in combination with sophisticated biochemical techniques that enable researchers to study these labile prosthetic groups under protected conditions (75).…”

Section: How Are Fe-s Clusters Delivered To Correct Recipient Proteins?mentioning

confidence: 99%

Biogenesis and functions of mammalian iron-sulfur proteins in the regulation of iron homeostasis and pivotal metabolic pathways

Rouault

Maio

2017

Journal of Biological Chemistry

129

109

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Fe-S cofactors are composed of iron and inorganic sulfur in various stoichiometries. A complex assembly pathway conducts their initial synthesis and subsequent binding to recipient proteins. In this minireview, we discuss how discovery of the role of the mammalian cytosolic aconitase, known as iron regulatory protein 1 (IRP1), led to the characterization of the function of its Fe-S cluster in sensing and regulating cellular iron homeostasis. Moreover, we present an overview of recent studies that have provided insights into the mechanism of Fe-S cluster transfer to recipient Fe-S proteins. Discovery of a regulatory role for an iron-sulfur cluster in iron regulatory protein 1Interest in understanding how mammalian cells regulated iron uptake and distribution in the 1980s led to the discovery of a post-transcriptional regulatory mechanism, which was found to be crucial for cellular and systemic iron homeostasis in vertebrates. It was known that the expression of a major iron storage protein, ferritin (Ft), 2 was primarily regulated at the translational rather than transcriptional level (1, 2). However, it was not possible to dissect how ferritin levels were controlled under different conditions of iron availability until the genes encoding H and L ferritin were cloned in 1984 (2). At that time, gel-shift assays were commonly used to demonstrate direct binding of specific transcription factors to DNA sequences. A similar approach revealed that one or more cytosolic proteins were bound to the 5Ј-untranslated (5Ј-UTR) region of ferritin transcripts in mammalian cells (3-5). Moreover, it appeared that the binding factors reflected the iron status of the cell, as ferritin translation and gel-shift binding activity were reduced in cells that were iron-deficient, while conversely increasing in cells that were iron-loaded. The region of the ferritin transcripts responsible for mediating translational regulation was identified and subsequently named the IRE, for iron-responsive element. The IRE was defined through mutagenesis and sequence homology as a short stem-loop structure located near the 5Ј-end of the ferritin transcript. Intensive efforts to identify cytosolic factors that bound to the IRE resulted in cloning of two major cytosolic regulatory proteins, iron regulatory proteins 1 and 2 (IRP1 and IRP2) (5). It was immediately apparent, upon inspection of its primary amino acid sequence, that IRP1 was remarkably similar to mitochondrial aconitase, which was a well-characterized Fe-S protein. A cubane [Fe 4 -S 4 ] cluster in the IRP1 active-site cleft was known to be critical for the reversible aconitase-mediated conversion of citrate to isocitrate (6), which is essential for cholesterol and fatty acid metabolism, as citrate is the substrate of ATP-citrate lyase, which generates acetyl-coenzyme A utilized for cholesterol and lipid biosynthesis. Additionally, citrate has important regulatory roles in glycolysis and fatty acid synthesis and oxidation (7). Isocitrate is also metabolized by the cytosolic NADP-dependent iso...

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Iron–sulfur clusters: from metals through mitochondria biogenesis to disease

2018

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Iron–sulfur clusters are ubiquitous inorganic co-factors that contribute to a wide range of cell pathways including the maintenance of DNA integrity, regulation of gene expression and protein translation, energy production, and antiviral response. Specifically, the iron–sulfur cluster biogenesis pathways include several proteins dedicated to the maturation of apoproteins in different cell compartments. Given the complexity of the biogenesis process itself, the iron–sulfur research area constitutes a very challenging and interesting field with still many unaddressed questions. Mutations or malfunctions affecting the iron–sulfur biogenesis machinery have been linked with an increasing amount of disorders such as Friedreich’s ataxia and various cardiomyopathies. This review aims to recap the recent discoveries both in the yeast and human iron–sulfur cluster arena, covering recent discoveries from chemistry to disease.

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Mammalian Fe–S proteins: definition of a consensus motif recognized by the co-chaperone HSC20

Cited by 31 publications

References 172 publications

Understanding the Molecular Basis of Multiple Mitochondrial Dysfunctions Syndrome 1 (MMDS1)—Impact of a Disease-Causing Gly208Cys Substitution on Structure and Activity of NFU1 in the Fe/S Cluster Biosynthetic Pathway

Understanding the Molecular Basis of Multiple Mitochondrial Dysfunctions Syndrome 1 (MMDS1)—Impact of a Disease-Causing Gly208Cys Substitution on Structure and Activity of NFU1 in the Fe/S Cluster Biosynthetic Pathway

Biogenesis and functions of mammalian iron-sulfur proteins in the regulation of iron homeostasis and pivotal metabolic pathways

Iron–sulfur clusters: from metals through mitochondria biogenesis to disease

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