scholarly journals Mouse Knock-out of IOP1 Protein Reveals Its Essential Role in Mammalian Cytosolic Iron-Sulfur Protein Biogenesis

2011 ◽  
Vol 286 (18) ◽  
pp. 15797-15805 ◽  
Author(s):  
Daisheng Song ◽  
Frank S. Lee
Keyword(s):  
Mammalian Cells ◽  
Essential Role ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Knock Out ◽  
Adult Mice ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Iron Sulfur Protein ◽  
Cellular Compartments

Iron-sulfur proteins play an essential role in a variety of biologic processes and exist in multiple cellular compartments. The biogenesis of these proteins has been the subject of extensive investigation, and particular focus has been placed on the pathways that assemble iron-sulfur clusters in the different cellular compartments. Iron-only hydrogenase-like protein 1 (IOP1; also known as nuclear prelamin A recognition factor like protein, or NARFL) is a human protein that is homologous to Nar1, a protein in Saccharomyces cerevisiae that, in turn, is an essential component of the cytosolic iron-sulfur protein assembly pathway in yeast. Previous siRNA-induced knockdown studies using mammalian cells point to a similar role for IOP1 in mammals. In the present studies, we pursued this further by knocking out Iop1 in Mus musculus. We find that Iop1 knock-out results in embryonic lethality before embryonic day 10.5. Acute, inducible global knock-out of Iop1 in adult mice results in lethality and significantly diminished activity of cytosolic aconitase, an iron-sulfur protein, in liver extracts. Inducible knock-out of Iop1 in mouse embryonic fibroblasts results in diminished activity of cytosolic but not mitochondrial aconitase and loss of cell viability. Therefore, just as with knock-out of Nar1 in yeast, we find that knock-out of Iop1/Narfl in mice results in lethality and defective cytosolic iron-sulfur cluster assembly. The findings demonstrate an essential role for IOP1 in this pathway.

scholarly journals IBA57 mutations abrogate iron-sulfur cluster assembly leading to cavitating leukoencephalopathy

2017 ◽  
Vol 3 (5) ◽  
pp. e184 ◽  
Author(s):  
Akihiko Ishiyama ◽  
Chika Sakai ◽  
Yuichi Matsushima ◽  
Satoru Noguchi ◽  
Satomi Mitsuhashi ◽  
...  
Keyword(s):  
Protein Expression ◽  
Lipoic Acid ◽  
Protein Assembly ◽  
Assembly System ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Mitochondrial Iron ◽  
Sulfur Protein ◽  
Iron Sulfur Protein

Objective:To determine the molecular factors contributing to progressive cavitating leukoencephalopathy (PCL) to help resolve the underlying genotype-phenotype associations in the mitochondrial iron-sulfur cluster (ISC) assembly system.Methods:The subjects were 3 patients from 2 families who showed no inconsistencies in either clinical or brain MRI findings as PCL. We used exome sequencing, immunoblotting, and enzyme activity assays to establish a molecular diagnosis and determine the roles of ISC-associated factors in PCL.Results:We performed genetic analyses on these 3 patients and identified compound heterozygosity for the IBA57 gene, which encodes the mitochondrial iron-sulfur protein assembly factor. Protein expression analysis revealed substantial decreases in IBA57 protein expression in myoblasts and fibroblasts. Immunoblotting revealed substantially reduced expression of SDHB, a subunit of complex II, and lipoic acid synthetase (LIAS). Levels of pyruvate dehydrogenase complex-E2 and α-ketoglutarate dehydrogenase-E2, which use lipoic acid as a cofactor, were also reduced. In activity staining, SDH activity was clearly reduced, but it was ameliorated in mitochondrial fractions from rescued myoblasts. In addition, NFU1 protein expression was also decreased, which is required for the assembly of a subset of iron-sulfur proteins to SDH and LIAS in the mitochondrial ISC assembly system.Conclusions:Defects in IBA57 essentially regulate NFU1 expression, and aberrant NFU1 ultimately affects SDH activity and LIAS expression in the ISC biogenesis pathway. This study provides new insights into the role of the iron-sulfur protein assembly system in disorders related to mitochondrial energy metabolism associated with leukoencephalopathy with cavities.

scholarly journals NapF Is a Cytoplasmic Iron-Sulfur Protein Required for Fe-S Cluster Assembly in the Periplasmic Nitrate Reductase

2004 ◽  
Vol 279 (48) ◽  
pp. 49727-49735 ◽  
Author(s):  
M. Francisca Olmo-Mira ◽  
Mónica Gavira ◽  
David J. Richardson ◽  
Francisco Castillo ◽  
Conrado Moreno-Vivián ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Cluster Assembly ◽  
Periplasmic Nitrate Reductase ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Iron Sulfur Protein

Dependence of heme biosynthesis on iron-sulfur cluster biogenesis: human ALAD is an unrecognized iron-sulfur protein

2020 ◽  
Author(s):  
Gang Liu ◽  
Debangsu Sil ◽  
Wing-Hang Tong ◽  
Nunziata Maio ◽  
J. Martin Bollinger ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Biosynthetic Pathway ◽  
Aminolevulinic Acid ◽  
Heme Biosynthesis ◽  
Second Step ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Iron Sulfur Protein

Abstract Heme biosynthesis and iron-sulfur cluster (ISC) biogenesis are two major mammalian metabolic pathways that require iron. It has long been known that these two pathways interconnect, but the previously described interactions do not fully explain why heme biosynthesis depends on intact ISC biogenesis. Herein we have identified a previously unrecognized connection between these two pathways through our discovery that human aminolevulinic acid dehydratase (ALAD), which catalyzes the second step of heme biosynthesis, is an Fe-S protein. We found that several highly conserved cysteines and an Ala306-Phe307-Arg308 motif of human ALAD are important for [Fe4S4] cluster acquisition and coordination. The enzymatic activity of human ALAD was greatly reduced upon loss of its Fe-S cluster, which resulted in reduced heme biosynthesis in human cells. Our findings explain why heme biosynthesis depends on intact ISC biogenesis, as ALAD provides an early Fe-S-dependent checkpoint in the heme biosynthetic pathway.

Mechanisms of Mitochondrial Iron-Sulfur Protein Biogenesis

2020 ◽  
Vol 89 (1) ◽  
pp. 471-499 ◽  
Author(s):  
Roland Lill ◽  
Sven-A. Freibert
Keyword(s):  
Molecular Mechanisms ◽  
De Novo ◽  
Lipid Synthesis ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Atp Production ◽  
Cellular Iron ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
S Proteins

Mitochondria are essential in most eukaryotes and are involved in numerous biological functions including ATP production, cofactor biosyntheses, apoptosis, lipid synthesis, and steroid metabolism. Work over the past two decades has uncovered the biogenesis of cellular iron-sulfur (Fe/S) proteins as the essential and minimal function of mitochondria. This process is catalyzed by the bacteria-derived iron-sulfur cluster assembly (ISC) machinery and has been dissected into three major steps: de novo synthesis of a [2Fe-2S] cluster on a scaffold protein; Hsp70 chaperone–mediated trafficking of the cluster and insertion into [2Fe-2S] target apoproteins; and catalytic conversion of the [2Fe-2S] into a [4Fe-4S] cluster and subsequent insertion into recipient apoproteins. ISC components of the first two steps are also required for biogenesis of numerous essential cytosolic and nuclear Fe/S proteins, explaining the essentiality of mitochondria. This review summarizes the molecular mechanisms underlying the ISC protein–mediated maturation of mitochondrial Fe/S proteins and the importance for human disease.

scholarly journals Thio Modification of Yeast Cytosolic tRNA Is an Iron-Sulfur Protein-Dependent Pathway

2007 ◽  
Vol 27 (8) ◽  
pp. 2841-2847 ◽  
Author(s):  
Yumi Nakai ◽  
Masato Nakai ◽  
Roland Lill ◽  
Tsutomu Suzuki ◽  
Hideyuki Hayashi
Keyword(s):  
Scaffold Proteins ◽  
Yeast Cells ◽  
Cluster Assembly ◽  
Cysteine Desulfurase ◽  
S Protein ◽  
Iron Sulfur ◽  
Severe Impairment ◽  
Sulfur Protein ◽  
Iron Sulfur Protein ◽  
Dependent Pathway

ABSTRACT Defects in the yeast cysteine desulfurase Nfs1 cause a severe impairment in the 2-thio modification of uridine of mitochondrial tRNAs (mt-tRNAs) and cytosolic tRNAs (cy-tRNAs). Nfs1 can also provide the sulfur atoms of the iron-sulfur (Fe/S) clusters generated by the mitochondrial and cytosolic Fe/S cluster assembly machineries, termed ISC and CIA, respectively. Therefore, a key question remains as to whether the biosynthesis of Fe/S clusters is a prerequisite for the 2-thio modification of the tRNAs in both of the subcellular compartments of yeast cells. To elucidate this question, we asked whether mitochondrial ISC and/or cytosolic CIA components besides Nfs1 were involved in the 2-thio modification of these tRNAs. We demonstrate here that the three CIA components, Cfd1, Nbp35, and Cia1, are required for the 2-thio modification of cy-tRNAs but not of mt-tRNAs. Interestingly, the mitochondrial scaffold proteins Isu1 and Isu2 are required for the 2-thio modification of the cy-tRNAs but not of the mt-tRNAs, while mitochondrial Nfs1 is required for both 2-thio modifications. These results clearly indicate that the 2-thio modification of cy-tRNAs is Fe/S protein dependent and thus requires both CIA and ISC machineries but that of mt-tRNAs is Fe/S cluster independent and does not require key mitochondrial ISC components except for Nfs1.

Identification and characterization of mitochondrial Mia40 as an iron–sulfur protein

2013 ◽  
Vol 455 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Michael P. Spiller ◽  
Swee Kim Ang ◽  
Efrain Ceh-Pavia ◽  
Karl Fisher ◽  
Qi Wang ◽  
...  
Keyword(s):  
Essential Role ◽  
Mitochondrial Protein ◽  
Mitochondrial Proteins ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Iron Sulfur Protein ◽  
Identification And Characterization

Mia40 is a highly conserved mitochondrial protein playing an essential role during biogenesis of mitochondrial proteins. Here we show that Mia40 is a novel iron–sulfur protein that binds a [2Fe–2S] cluster in a dimer form with its CPC motifs.

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