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Zarges C, Riemer J. Oxidative protein folding in the intermembrane space of human mitochondria. FEBS Open Bio 2024; 14:1610-1626. [PMID: 38867508 PMCID: PMC11452306 DOI: 10.1002/2211-5463.13839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/03/2024] [Accepted: 05/23/2024] [Indexed: 06/14/2024] Open
Abstract
The mitochondrial intermembrane space hosts a machinery for oxidative protein folding, the mitochondrial disulfide relay. This machinery imports a large number of soluble proteins into the compartment, where they are retained through oxidative folding. Additionally, the disulfide relay enhances the stability of many proteins by forming disulfide bonds. In this review, we describe the mitochondrial disulfide relay in human cells, its components, and their coordinated collaboration in mechanistic detail. We also discuss the human pathologies associated with defects in this machinery and its protein substrates, providing a comprehensive overview of its biological importance and implications for health.
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Affiliation(s)
| | - Jan Riemer
- Institute for BiochemistryUniversity of CologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneGermany
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2
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Jacobs LJHC, Riemer J. Maintenance of small molecule redox homeostasis in mitochondria. FEBS Lett 2023; 597:205-223. [PMID: 36030088 DOI: 10.1002/1873-3468.14485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 01/26/2023]
Abstract
Compartmentalisation of eukaryotic cells enables fundamental otherwise often incompatible cellular processes. Establishment and maintenance of distinct compartments in the cell relies not only on proteins, lipids and metabolites but also on small redox molecules. In particular, small redox molecules such as glutathione, NAD(P)H and hydrogen peroxide (H2 O2 ) cooperate with protein partners in dedicated machineries to establish specific subcellular redox compartments with conditions that enable oxidative protein folding and redox signalling. Dysregulated redox homeostasis has been directly linked with a number of diseases including cancer, neurological disorders, cardiovascular diseases, obesity, metabolic diseases and ageing. In this review, we will summarise mechanisms regulating establishment and maintenance of redox homeostasis in the mitochondrial subcompartments of mammalian cells.
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Affiliation(s)
- Lianne J H C Jacobs
- Institute for Biochemistry and Center of Excellence for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany
| | - Jan Riemer
- Institute for Biochemistry and Center of Excellence for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany
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3
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Dong Y, Zhang Y, Feng Y, An W. The protective roles of augmenter of liver regeneration in hepatocytes in the non-alcoholic fatty liver disease. Front Pharmacol 2022; 13:928606. [PMID: 36304168 PMCID: PMC9592723 DOI: 10.3389/fphar.2022.928606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/20/2022] [Indexed: 11/23/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) occurs in 25% of the global population and manifests as lipid deposition, hepatocyte injury, activation of Kupffer and stellate cells, and steatohepatitis. Predominantly expressed in hepatocytes, the augmenter of liver regeneration (ALR) is a key factor in liver regulation that can alleviate fatty liver disease and protect the liver from abnormal liver lipid metabolism. ALR has three isoforms (15-, 21-, and 23-kDa), amongst which 23-kDa ALR is the most extensively studied. The 23-kDa ALR isoform is a sulfhydryl oxidase that resides primarily in the mitochondrial intermembrane space (IMS), whereby it protects the liver against various types of injury. In this review, we describe the role of ALR in regulating hepatocytes in the context of NAFLD. We also discuss questions about ALR that remain to be explored in the future. In conclusion, ALR appears to be a promising therapeutic target for treating NAFLD.
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Affiliation(s)
- Yuan Dong
- Department of Science and Technology, Beijing Youan Hospital, Capital Medical University, Beijing, China
| | - Yuejie Zhang
- Department of Science and Technology, Beijing Youan Hospital, Capital Medical University, Beijing, China
| | - Yingmei Feng
- Department of Science and Technology, Beijing Youan Hospital, Capital Medical University, Beijing, China
- *Correspondence: Yingmei Feng, ; Wei An,
| | - Wei An
- Department of Cell Biology, Capital Medical University and the Municipal Key Laboratory for Liver Protection and Regulation of Regeneration, Beijing, China
- *Correspondence: Yingmei Feng, ; Wei An,
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4
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Finger Y, Riemer J. Protein import by the mitochondrial disulfide relay in higher eukaryotes. Biol Chem 2021; 401:749-763. [PMID: 32142475 DOI: 10.1515/hsz-2020-0108] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/24/2020] [Indexed: 12/19/2022]
Abstract
The proteome of the mitochondrial intermembrane space (IMS) contains more than 100 proteins, all of which are synthesized on cytosolic ribosomes and consequently need to be imported by dedicated machineries. The mitochondrial disulfide relay is the major import machinery for soluble proteins in the IMS. Its major component, the oxidoreductase MIA40, interacts with incoming substrates, retains them in the IMS, and oxidatively folds them. After this reaction, MIA40 is reoxidized by the sulfhydryl oxidase augmenter of liver regeneration, which couples disulfide formation by this machinery to the activity of the respiratory chain. In this review, we will discuss the import of IMS proteins with a focus on recent findings showing the diversity of disulfide relay substrates, describing the cytosolic control of this import system and highlighting the physiological relevance of the disulfide relay machinery in higher eukaryotes.
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Affiliation(s)
- Yannik Finger
- Institute for Biochemistry, Redox Biochemistry, University of Cologne, Zülpicher Str. 47a/R. 3.49, D-50674 Cologne, Germany
| | - Jan Riemer
- Department of Chemistry, Institute for Biochemistry, Redox Biochemistry, University of Cologne, and Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases, Zülpicher Str. 47a/R. 3.49, D-50674 Cologne, Germany
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Chang HC, Shapiro JS, Jiang X, Senyei G, Sato T, Geier J, Sawicki KT, Ardehali H. Augmenter of liver regeneration regulates cellular iron homeostasis by modulating mitochondrial transport of ATP-binding cassette B8. eLife 2021; 10:e65158. [PMID: 33835027 PMCID: PMC8055271 DOI: 10.7554/elife.65158] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/06/2021] [Indexed: 12/15/2022] Open
Abstract
Chronic loss of Augmenter of Liver Regeneration (ALR) results in mitochondrial myopathy with cataracts; however, the mechanism for this disorder remains unclear. Here, we demonstrate that loss of ALR, a principal component of the MIA40/ALR protein import pathway, results in impaired cytosolic Fe/S cluster biogenesis in mammalian cells. Mechanistically, MIA40/ALR facilitates the mitochondrial import of ATP-binding cassette (ABC)-B8, an inner mitochondrial membrane protein required for cytoplasmic Fe/S cluster maturation, through physical interaction with ABCB8. Downregulation of ALR impairs mitochondrial ABCB8 import, reduces cytoplasmic Fe/S cluster maturation, and increases cellular iron through the iron regulatory protein-iron response element system. Our finding thus provides a mechanistic link between MIA40/ALR import machinery and cytosolic Fe/S cluster maturation through the mitochondrial import of ABCB8, and offers a potential explanation for the pathology seen in patients with ALR mutations.
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Affiliation(s)
- Hsiang-Chun Chang
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Jason Solomon Shapiro
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Xinghang Jiang
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Grant Senyei
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Teruki Sato
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Justin Geier
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Konrad T Sawicki
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
| | - Hossein Ardehali
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University School of MedicineChicagoUnited States
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Fekri A, Keshk EM, Khalil AGM, Taha I. Synthesis of novel antioxidant and antitumor 5-aminopyrazole derivatives, 2D/3D QSAR, and molecular docking. Mol Divers 2021; 26:781-800. [PMID: 33683569 DOI: 10.1007/s11030-021-10184-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 01/16/2021] [Indexed: 12/12/2022]
Abstract
5-Aminopyrazole serves as a vital precursor for several biologically active pyrazoloazines, including pyrazolopyridine, pyrazolopyrimidine, and pyrazolotriazine, as well as Schiff bases, thiourea, and phthalimide derivatives. In this study, we structurally characterized novel pyrazole derivatives by spectral IR, 1H and 13C NMR, and MASS spectroscopy. We also evaluated antioxidant activity of various derivatives using ABTS and DPPH methods and cytotoxicity in the hepatocellular carcinoma Hep-G2 cells by SRB assay. The most potent antitumor molecules were 5-aminopyrazole derivative 3, chloroacetanilide derivative 8, maleimide derivative 10a, pyrazolopyrimidine 16, and enamine 19, with IC50 values of 41, 3.6, 37, 24.4, and 17.7 μM, respectively. Complementary computational studies predicted QSAR and bioactivity of these molecules. Interestingly, the most effective compounds were also predicted to be kinase inhibitors; in addition, molecular docking with liver receptors (3MBG, 4XCU, and 4G9C) predicted promising interactions.
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Affiliation(s)
- Ahmed Fekri
- Chemistry Department, Faculty of Science, Mansoura University, 25 El Gomhouria St, Mansoura, Dakahlia Governorate, 35516, Egypt.
| | - Eman M Keshk
- Chemistry Department, Faculty of Science, Mansoura University, 25 El Gomhouria St, Mansoura, Dakahlia Governorate, 35516, Egypt
| | - Abdel-Galil M Khalil
- Chemistry Department, Faculty of Science, Mansoura University, 25 El Gomhouria St, Mansoura, Dakahlia Governorate, 35516, Egypt
| | - Israa Taha
- Chemistry Department, Faculty of Science, Mansoura University, 25 El Gomhouria St, Mansoura, Dakahlia Governorate, 35516, Egypt
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Effects of Liposome and Cardiolipin on Folding and Function of Mitochondrial Erv1. Int J Mol Sci 2020; 21:ijms21249402. [PMID: 33321986 PMCID: PMC7764442 DOI: 10.3390/ijms21249402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 11/25/2022] Open
Abstract
Erv1 (EC number 1.8.3.2) is an essential mitochondrial enzyme catalyzing protein import and oxidative folding in the mitochondrial intermembrane space. Erv1 has both oxidase and cytochrome c reductase activities. While both Erv1 and cytochrome c were reported to be membrane associated in mitochondria, it is unknown how the mitochondrial membrane environment may affect the function of Erv1. Here, in this study, we used liposomes to mimic the mitochondrial membrane and investigated the effect of liposomes and cardiolipin on the folding and function of yeast Erv1. Enzyme kinetics of both the oxidase and cytochrome c reductase activity of Erv1 were studied using oxygen consumption analysis and spectroscopic methods. Our results showed that the presence of liposomes has mild impacts on Erv1 oxidase activity, but significantly inhibited the catalytic efficiency of Erv1 cytochrome c reductase activity in a cardiolipin-dependent manner. Taken together, the results of this study provide important insights into the function of Erv1 in the mitochondria, suggesting that molecular oxygen is a better substrate than cytochrome c for Erv1 in the yeast mitochondria.
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Meyer AJ, Riemer J, Rouhier N. Oxidative protein folding: state-of-the-art and current avenues of research in plants. THE NEW PHYTOLOGIST 2019; 221:1230-1246. [PMID: 30230547 DOI: 10.1111/nph.15436] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 08/01/2018] [Indexed: 06/08/2023]
Abstract
Contents Summary 1230 I. Introduction 1230 II. Formation and isomerization of disulfides in the ER and the Golgi apparatus 1231 III. The disulfide relay in the mitochondrial intermembrane space: why are plants different? 1236 IV. Disulfide bond formation on luminal proteins in thylakoids 1240 V. Conclusion 1242 Acknowledgements 1242 References 1242 SUMMARY: Disulfide bonds are post-translational modifications crucial for the structure and function of thousands of proteins. Their formation and isomerization, referred to as oxidative folding, require specific protein machineries found in oxidizing subcellular compartments, namely the endoplasmic reticulum and the associated endomembrane system, the intermembrane space of mitochondria and the thylakoid lumen of chloroplasts. At least one protein component is required for transferring electrons from substrate proteins to an acceptor that is usually molecular oxygen. For oxidation reactions, incoming reduced substrates are oxidized by thiol-oxidoreductase proteins (or domains in case of chimeric proteins), which are usually themselves oxidized by a single thiol oxidase, the enzyme generating disulfide bonds de novo. By contrast, the description of the molecular actors and pathways involved in proofreading and isomerization of misfolded proteins, which require a tightly controlled redox balance, lags behind. Herein we provide a general overview of the knowledge acquired on the systems responsible for oxidative protein folding in photosynthetic organisms, highlighting their particularities compared to other eukaryotes. Current research challenges are discussed including the importance and specificity of these oxidation systems in the context of the existence of reducing systems in the same compartments.
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Affiliation(s)
- Andreas J Meyer
- INRES-Chemical Signalling, University of Bonn, 53113, Bonn, Germany
| | - Jan Riemer
- Institute of Biochemistry, University of Cologne, 50674, Cologne, Germany
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Augmenter of liver regeneration: Essential for growth and beyond. Cytokine Growth Factor Rev 2018; 45:65-80. [PMID: 30579845 DOI: 10.1016/j.cytogfr.2018.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/12/2018] [Accepted: 12/14/2018] [Indexed: 12/11/2022]
Abstract
Liver regeneration is a well-orchestrated process that is triggered by tissue loss due to trauma or surgical resection and by hepatocellular death induced by toxins or viral infections. Due to the central role of the liver for body homeostasis, intensive research was conducted to identify factors that might contribute to hepatic growth and regeneration. Using a model of partial hepatectomy several factors including cytokines and growth factors that regulate this process were discovered. Among them, a protein was identified to specifically support liver regeneration and therefore was named ALR (Augmenter of Liver Regeneration). ALR protein is encoded by GFER (growth factor erv1-like) gene and can be regulated by various stimuli. ALR is expressed in different tissues in three isoforms which are associated with multiple functions: The long forms of ALR were found in the inner-mitochondrial space (IMS) and the cytosol. Mitochondrial ALR (23 kDa) was shown to cooperate with Mia40 to insure adequate protein folding during import into IMS. On the other hand short form ALR, located mainly in the cytosol, was attributed with anti-apoptotic and anti-oxidative properties as well as its inflammation and metabolism modulating effects. Although a considerable amount of work has been devoted to summarizing the knowledge on ALR, an investigation of ALR expression in different organs (location, subcellular localization) as well as delineation between the isoforms and function of ALR is still missing. This review provides a comprehensive evaluation of ALR structure and expression of different ALR isoforms. Furthermore, we highlight the functional role of endogenously expressed and exogenously applied ALR, as well as an analysis of the clinical importance of ALR, with emphasis on liver disease and in vivo models, as well as the consequences of mutations in the GFER gene.
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Mitochondrial diseases caused by dysfunctional mitochondrial protein import. Biochem Soc Trans 2018; 46:1225-1238. [PMID: 30287509 DOI: 10.1042/bst20180239] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/20/2018] [Accepted: 08/31/2018] [Indexed: 12/18/2022]
Abstract
Mitochondria are essential organelles which perform complex and varied functions within eukaryotic cells. Maintenance of mitochondrial health and functionality is thus a key cellular priority and relies on the organelle's extensive proteome. The mitochondrial proteome is largely encoded by nuclear genes, and mitochondrial proteins must be sorted to the correct mitochondrial sub-compartment post-translationally. This essential process is carried out by multimeric and dynamic translocation and sorting machineries, which can be found in all four mitochondrial compartments. Interestingly, advances in the diagnosis of genetic disease have revealed that mutations in various components of the human import machinery can cause mitochondrial disease, a heterogenous and often severe collection of disorders associated with energy generation defects and a multisystem presentation often affecting the cardiovascular and nervous systems. Here, we review our current understanding of mitochondrial protein import systems in human cells and the molecular basis of mitochondrial diseases caused by defects in these pathways.
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Habich M, Salscheider SL, Riemer J. Cysteine residues in mitochondrial intermembrane space proteins: more than just import. Br J Pharmacol 2018; 176:514-531. [PMID: 30129023 DOI: 10.1111/bph.14480] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/20/2018] [Accepted: 06/26/2018] [Indexed: 12/13/2022] Open
Abstract
The intermembrane space (IMS) is a very small mitochondrial sub-compartment with critical relevance for many cellular processes. IMS proteins fulfil important functions in transport of proteins, lipids, metabolites and metal ions, in signalling, in metabolism and in defining the mitochondrial ultrastructure. Our understanding of the IMS proteome has become increasingly refined although we still lack information on the identity and function of many of its proteins. One characteristic of many IMS proteins are conserved cysteines. Different post-translational modifications of these cysteine residues can have critical roles in protein function, localization and/or stability. The close localization to different ROS-producing enzyme systems, a dedicated machinery for oxidative protein folding, and a unique equipment with antioxidative systems, render the careful balancing of the redox and modification states of the cysteine residues, a major challenge in the IMS. In this review, we discuss different functions of human IMS proteins, the involvement of cysteine residues in these functions, the consequences of cysteine modifications and the consequences of cysteine mutations or defects in the machinery for disulfide bond formation in terms of human health. LINKED ARTICLES: This article is part of a themed section on Chemical Biology of Reactive Sulfur Species. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.4/issuetoc.
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Affiliation(s)
- Markus Habich
- Department of Chemistry, Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Silja Lucia Salscheider
- Department of Chemistry, Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Jan Riemer
- Department of Chemistry, Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
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Peleh V, Zannini F, Backes S, Rouhier N, Herrmann JM. Erv1 of Arabidopsis thaliana can directly oxidize mitochondrial intermembrane space proteins in the absence of redox-active Mia40. BMC Biol 2017; 15:106. [PMID: 29117860 PMCID: PMC5679390 DOI: 10.1186/s12915-017-0445-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/19/2017] [Indexed: 11/20/2022] Open
Abstract
Background Many proteins of the mitochondrial intermembrane space (IMS) contain structural disulfide bonds formed by the mitochondrial disulfide relay. In fungi and animals, the sulfhydryl oxidase Erv1 ‘generates’ disulfide bonds that are passed on to the oxidoreductase Mia40, which oxidizes substrate proteins. A different structural organization of plant Erv1 proteins compared to that of animal and fungal orthologs was proposed to explain its inability to complement the corresponding yeast mutant. Results Herein, we have revisited the biochemical and functional properties of Arabidopsis thaliana Erv1 by both in vitro reconstituted activity assays and complementation of erv1 and mia40 yeast mutants. These mutants were viable, however, they showed severe defects in the biogenesis of IMS proteins. The plant Erv1 was unable to oxidize yeast Mia40 and rather even blocked its activity. Nevertheless, it was able to mediate the import and folding of mitochondrial proteins. Conclusions We observed that plant Erv1, unlike its homologs in fungi and animals, can promote protein import and oxidative protein folding in the IMS independently of the oxidoreductase Mia40. In accordance to the absence of Mia40 in many protists, our study suggests that the mitochondrial disulfide relay evolved in a stepwise reaction from an Erv1-only system to which Mia40 was added in order to improve substrate specificity. The mitochondrial disulfide relay evolved in a step-wise manner from an Erv1-only system. ![]()
Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0445-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Valentina Peleh
- Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663, Kaiserslautern, Germany
| | - Flavien Zannini
- Unité Mixte de Recherches 1136 Interactions Arbres-Microorganismes, Université de Lorraine/INRA, Faculté des sciences et technologies, 54500 Vandoeuvre-lès-Nancy, Nancy, France
| | - Sandra Backes
- Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663, Kaiserslautern, Germany
| | - Nicolas Rouhier
- Unité Mixte de Recherches 1136 Interactions Arbres-Microorganismes, Université de Lorraine/INRA, Faculté des sciences et technologies, 54500 Vandoeuvre-lès-Nancy, Nancy, France.
| | - Johannes M Herrmann
- Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663, Kaiserslautern, Germany.
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Senćanski M, Djordjević I, Grubišić S. Assessing the dispersive and electrostatic components of the selenium–aromatic interaction energy by DFT. J Mol Model 2017; 23:162. [DOI: 10.1007/s00894-017-3330-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/27/2017] [Indexed: 11/28/2022]
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Wasilewski M, Chojnacka K, Chacinska A. Protein trafficking at the crossroads to mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:125-137. [PMID: 27810356 DOI: 10.1016/j.bbamcr.2016.10.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 12/14/2022]
Abstract
Mitochondria are central power stations in the cell, which additionally serve as metabolic hubs for a plethora of anabolic and catabolic processes. The sustained function of mitochondria requires the precisely controlled biogenesis and expression coordination of proteins that originate from the nuclear and mitochondrial genomes. Accuracy of targeting, transport and assembly of mitochondrial proteins is also needed to avoid deleterious effects on protein homeostasis in the cell. Checkpoints of mitochondrial protein transport can serve as signals that provide information about the functional status of the organelles. In this review, we summarize recent advances in our understanding of mitochondrial protein transport and discuss examples that involve communication with the nucleus and cytosol.
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Affiliation(s)
- Michal Wasilewski
- International Institute of Molecular and Cell Biology in Warsaw, Poland.
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15
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Mitochondrial disulfide relay and its substrates: mechanisms in health and disease. Cell Tissue Res 2016; 367:59-72. [DOI: 10.1007/s00441-016-2481-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/18/2016] [Indexed: 01/06/2023]
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Lipid deposition in liver cells: The influence of short form augmenter of liver regeneration. Clin Res Hepatol Gastroenterol 2016; 40:186-94. [PMID: 26476698 DOI: 10.1016/j.clinre.2015.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/11/2015] [Accepted: 07/15/2015] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND OBJECTIVE The short form augmenter of liver regeneration (sfALR) is a novel human hepatotrophic growth factor. The aim of this study was to investigate the potential role of sfALR in NAFLD. METHODS The free fatty acids (FFA) induced lipid accumulation in mouse liver parenchymal cells was examined by Oil Red O staining and triglyceride level determination. The cell cycle was determined by flow cytometry and the proliferation was assessed by CCK8. The expression levels of gfer, miR-122, srebp-1c, fas, dgat2, acc1 and Lrp1B were assessed by quantitative real-time PCR. Furthermore, the MAPK pathway was detected by western blot. RESULTS The results showed that sfALR could alleviate the lipid accumulation in mice both in vivo and in vitro. sfALR relieved the proliferation inhibition and G2 arrest of mouse liver parenchymal cells induced by FFAs. Free fatty acids affected gfer expression in a time-and dose-dependent way. And sfALR suppressed JNK activation, increased miR-122 level and reduced fatty acid synthesis-related gene expression. CONCLUSION These findings suggested that sfALR could alleviate the severity of fatty liver in mice.
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Calderwood L, Holm IA, Teot LA, Anselm I. Adrenal Insufficiency in Mitochondrial Disease: A Rare Case of GFER-Related Mitochondrial Encephalomyopathy and Review of the Literature. J Child Neurol 2016; 31:190-4. [PMID: 26018198 DOI: 10.1177/0883073815587327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 04/24/2015] [Indexed: 11/15/2022]
Abstract
GFER-related mitochondrial encephalomyopathy has been previously described only in 3 siblings of a consanguineous Moroccan family. Their phenotype included congenital cataracts, hypotonia, developmental delay, and sensorineural hearing loss. Multiple mitochondrial respiratory chain complex deficiencies were identified on muscle biopsy. We describe a now-19-year-old woman with adrenal insufficiency, lactic acidosis, congenital cataracts, and respiratory insufficiency secondary to mitochondrial disorder, who was reported by North et al (1996) as a toddler. Compound heterozygous GFER mutations c.373C>T (Q125X) and c.581G>A (R194 H) were recently discovered in this patient. The purpose of this report is (1) to expand the phenotype this ultra-rare disorder and (2) to provide a review of the literature describing the unique finding of adrenal insufficiency in patients with molecularly confirmed disorders of mitochondrial metabolism.
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Affiliation(s)
- Laurel Calderwood
- Department of Obstetrics and Gynecology, Boston University School of Medicine, Boston, MA, USA
| | - Ingrid A Holm
- Division of Genetics and Genomics, Division of Endocrinology, Department of Medicine, Manton Center for Orphan Diseases Research, Boston Children's Hospital, Boston, MA, USA Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Lisa A Teot
- Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Irina Anselm
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
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Abstract
Erv1 (essential for respiration and viability 1) is a FAD-dependent sulphydryl oxidase with a tryptophan-rich catalytic domain. We show that Trp95 and Trp183 are important for stabilizing the folding, FAD-binding, and function of Erv1, whilst other four tryptophan residues are not functionally important. Erv1 is an FAD-dependent thiol oxidase of the ERV (essential for respiration and viability)/ALR (augmenter of liver regeneration) sub-family and an essential component of the mitochondrial import and assembly pathway. Erv1 contains six tryptophan residues, which are all located in the highly conserved C-terminal FAD-binding domain. Though important structural roles were predicted for the invariable Trp95, no experimental study has been reported. In the present study, we investigated the structural and functional roles of individual tryptophan residues of Erv1. Six single tryptophan-to-phenylalanine yeast mutant strains were generated and their effects on cell viability were tested at various temperatures. Then, the mutants were purified from Escherichia coli. Their effects on folding, FAD-binding and Erv1 activity were characterized. Our results showed that Erv1W95F has the strongest effect on the stability and function of Erv1 and followed by Erv1W183F. Erv1W95F results in a decrease in the Tm of Erv1 by 23°C, a significant loss of the oxidase activity and thus causing cell growth defects at both 30°C and 37°C. Erv1W183F induces changes in the oligomerization state of Erv1, along with a pronounced effect on the stability of Erv1 and its function at 37°C, whereas the other mutants had no clear effect on the function of Erv1 including the highly conserved Trp157 mutant. Finally, computational analysis indicates that Trp95 plays a key role in stabilizing the isoalloxazine ring to interact with Cys133. Taken together, the present study provided important insights into the molecular mechanism of how thiol oxidases use FAD in catalysing disulfide bond formation.
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A Perspective on Transport of Proteins into Mitochondria: A Myriad of Open Questions. J Mol Biol 2015; 427:1135-58. [DOI: 10.1016/j.jmb.2015.02.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/22/2022]
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Prehna G, Ramirez BE, Lovering AL. The lifestyle switch protein Bd0108 of Bdellovibrio bacteriovorus is an intrinsically disordered protein. PLoS One 2014; 9:e115390. [PMID: 25514156 PMCID: PMC4267844 DOI: 10.1371/journal.pone.0115390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 11/21/2014] [Indexed: 01/15/2023] Open
Abstract
Bdellovibrio bacteriovorus is a δ-proteobacterium that preys upon Salmonella spp., E. coli, and other Gram-negative bacteria. Bdellovibrio can grow axenically (host-independent, HI, rare and mutation-driven) or subsist via a predatory lifecycle (host-dependent, HD, the usual case). Upon contact with prey, B. bacteriovorus enters the host periplasm from where it slowly drains the host cytosol of nutrients for its own replication. At the core of this mechanism is a retractile pilus, whose architecture is regulated by the protein Bd0108 and its interaction with the neighboring gene product Bd0109. Deletion of bd0108 results in negligible pilus formation, whereas an internal deletion (the one that instigates host-independence) causes mis-regulation of pilus length. These mutations, along with a suite of naturally occurring bd0108 mutant strains, act to control the entry to HI growth. To further study the molecular mechanism of predatory regulation, we focused on the apparent lifecycle switch protein Bd0108. Here we characterize the solution structure and dynamics of Bd0108 using nuclear magnetic resonance (NMR) spectroscopy complemented with additional biophysical methods. We then explore the interaction between Bd0108 and Bd0109 in detail utilizing isothermal titration calorimetry (ITC) and NMR spectroscopy. Together our results demonstrate that Bd0108 is an intrinsically disordered protein (IDP) and that the interaction with Bd0109 is of low affinity. Furthermore, we observe that Bd0108 retains an IDP nature while binding Bd0109. From our data we conclude that Bdellovibrio bacteriovorus utilizes an intrinsically disordered protein to regulate its pilus and control predation signaling.
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Affiliation(s)
- Gerd Prehna
- Center for Structural Biology, Research Resources Center, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Benjamin E. Ramirez
- Center for Structural Biology, Research Resources Center, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Andrew L. Lovering
- Institute of Microbiology & Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
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21
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The disease-associated mutation of the mitochondrial thiol oxidase Erv1 impairs cofactor binding during its catalytic reaction. Biochem J 2014; 464:449-59. [DOI: 10.1042/bj20140679] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Erv1 is a mitochondrial FAD-dependent thiol oxidase. We show that the Erv1 R182H mutant impairs cofactor binding to its catalytic intermediates, providing a model for molecular basis of the functional defect of the disease-associated mutation.
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Balancing oxidative protein folding: The influences of reducing pathways on disulfide bond formation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1383-90. [DOI: 10.1016/j.bbapap.2014.02.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/31/2014] [Accepted: 02/07/2014] [Indexed: 11/20/2022]
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23
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Mitochondrial protein translocases for survival and wellbeing. FEBS Lett 2014; 588:2484-95. [DOI: 10.1016/j.febslet.2014.05.028] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/15/2014] [Accepted: 05/15/2014] [Indexed: 11/20/2022]
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24
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Schaefer-Ramadan S, Thorpe C, Rozovsky S. Site-specific insertion of selenium into the redox-active disulfide of the flavoprotein augmenter of liver regeneration. Arch Biochem Biophys 2014; 548:60-5. [PMID: 24582598 PMCID: PMC4009370 DOI: 10.1016/j.abb.2014.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/29/2014] [Accepted: 02/03/2014] [Indexed: 11/23/2022]
Abstract
Augmenter of liver regeneration (sfALR) is a small disulfide-bridged homodimeric flavoprotein with sulfhydryl oxidase activity. Here, we investigate the catalytic and spectroscopic consequences of selectively replacing C145 by a selenocysteine to complement earlier studies in which random substitution of ∼90% of the 6 cysteine residues per sfALR monomer was achieved growing Escherichia coli on selenite. A selenocysteine insertion sequence (SECIS) element was installed within the gene for human sfALR. SecALR2 showed a spectrum comparable to that of wild-type sfALR. The catalytic efficiency of SecALR2 towards dithiothreitol was 6.8-fold lower than a corresponding construct in which position 145 was returned to a cysteine residue while retaining the additional mutations introduced with the SECIS element. This all-cysteine control enzyme formed a mixed disulfide between C142 and β-mercaptoethanol releasing C145 to form a thiolate-flavin charge transfer absorbance band at ∼530nm. In contrast, SecALR2 showed a prominent long-wavelength absorbance at 585 nm consistent with the expectation that a selenolate would be a better charge-transfer donor to the isoalloxazine ring. These data show the robustness of the ALR protein fold towards the multiple mutations required to insert the SECIS element and provide the first example of a selenolate to flavin charge-transfer complex.
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Affiliation(s)
| | - Colin Thorpe
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States.
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25
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The mitochondrial disulfide relay system: roles in oxidative protein folding and beyond. Int J Cell Biol 2013; 2013:742923. [PMID: 24348563 PMCID: PMC3848088 DOI: 10.1155/2013/742923] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/01/2013] [Indexed: 12/31/2022] Open
Abstract
Disulfide bond formation drives protein import of most proteins of the mitochondrial intermembrane space (IMS). The main components of this disulfide relay machinery are the oxidoreductase Mia40 and the sulfhydryl oxidase Erv1/ALR. Their precise functions have been elucidated in molecular detail for the yeast and human enzymes in vitro and in intact cells. However, we still lack knowledge on how Mia40 and Erv1/ALR impact cellular and organism physiology and whether they have functions beyond their role in disulfide bond formation. Here we summarize the principles of oxidation-dependent protein import mediated by the mitochondrial disulfide relay. We proceed by discussing recently described functions of Mia40 in the hypoxia response and of ALR in influencing mitochondrial morphology and its importance for tissue development and embryogenesis. We also include a discussion of the still mysterious function of Erv1/ALR in liver regeneration.
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26
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Schaefer-Ramadan S, Gannon SA, Thorpe C. Human augmenter of liver regeneration: probing the catalytic mechanism of a flavin-dependent sulfhydryl oxidase. Biochemistry 2013; 52:8323-32. [PMID: 24147449 DOI: 10.1021/bi401305w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Augmenter of liver regeneration is a member of the ERV family of small flavin-dependent sulfhydryl oxidases that contain a redox-active CxxC disulfide bond in redox communication with the isoalloxazine ring of bound FAD. These enzymes catalyze the oxidation of thiol substrates with the reduction of molecular oxygen to hydrogen peroxide. This work studies the catalytic mechanism of the short, cytokine form of augmenter of liver regeneration (sfALR) using model thiol substrates of the enzyme. The redox potential of the proximal disulfide in sfALR was found to be approximately 57 mV more reducing than the flavin chromophore, in agreement with titration experiments. Rapid reaction studies show that dithiothreitol (DTT) generates a transient mixed disulfide intermediate with sfALR signaled by a weak charge-transfer interaction between the thiolate of C145 and the oxidized flavin. The subsequent transfer of reducing equivalents to the flavin ring is relatively slow, with a limiting apparent rate constant of 12.4 s(-1). However, reoxidation of the reduced flavin by molecular oxygen is even slower (2.3 s(-1) at air saturation) and thus largely limits turnover at 5 mM DTT. The nature of the charge-transfer complexes observed with DTT was explored using a range of simple monothiols to mimic the initial nucleophilic attack on the proximal disulfide. While β-mercaptoethanol is a very poor substrate of sfALR (∼0.3 min(-1) at 100 mM thiol), it rapidly generates a mixed disulfide intermediate allowing the thiolate of C145 to form a strong charge-transfer complex with the flavin. Unlike the other monothiols tested, glutathione is unable to form charge-transfer complexes and is an undetectable substrate of the oxidase. These data are rationalized on the basis of the stringent steric requirements for thiol-disulfide exchange reactions. The inability of the relatively bulky glutathione to attain the in-line geometry required for efficient disulfide exchange in sfALR may be physiologically important in preventing the oxidase from catalyzing the potentially harmful oxidation of intracellular glutathione.
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Affiliation(s)
- Stephanie Schaefer-Ramadan
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716-2522, United States
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27
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Kallergi E, Kalef-Ezra E, Karagouni-Dalakoura K, Tokatlidis K. Common Players in Mitochondria Biogenesis and Neuronal Protection Against Stress-Induced Apoptosis. Neurochem Res 2013; 39:546-55. [DOI: 10.1007/s11064-013-1109-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
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28
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Banci L, Bertini I, Cefaro C, Ciofi-Baffoni S, Gajda K, Felli IC, Gallo A, Pavelkova A, Kallergi E, Andreadaki M, Katrakili N, Pozidis C, Tokatlidis K. An intrinsically disordered domain has a dual function coupled to compartment-dependent redox control. J Mol Biol 2013; 425:594-608. [PMID: 23207295 DOI: 10.1016/j.jmb.2012.11.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 11/03/2012] [Accepted: 11/25/2012] [Indexed: 11/20/2022]
Abstract
The functional role of unstructured protein domains is an emerging field in the frame of intrinsically disordered proteins. The involvement of intrinsically disordered domains (IDDs) in protein targeting and biogenesis processes in mitochondria is so far not known. Here, we have characterized the structural/dynamic and functional properties of an IDD of the sulfhydryl oxidase ALR (augmenter of liver regeneration) located in the intermembrane space of mitochondria. At variance to the unfolded-to-folded structural transition of several intrinsically disordered proteins, neither substrate recognition events nor redox switch of its shuttle cysteine pair is linked to any such structural change. However, this unstructured domain performs a dual function in two cellular compartments: it acts (i) as a mitochondrial targeting signal in the cytosol and (ii) as a crucial recognition site in the disulfide relay system of intermembrane space. This domain provides an exciting new paradigm for IDDs ensuring two distinct functions that are linked to intracellular organelle targeting.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
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29
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Fraga H, Ventura S. Oxidative folding in the mitochondrial intermembrane space in human health and disease. Int J Mol Sci 2013; 14:2916-27. [PMID: 23364613 PMCID: PMC3588022 DOI: 10.3390/ijms14022916] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 01/21/2013] [Accepted: 01/23/2013] [Indexed: 11/22/2022] Open
Abstract
Oxidative folding in the mitochondrial intermembrane space (IMS) is a key cellular event associated with the folding and import of a large and still undetermined number of proteins. This process is catalyzed by an oxidoreductase, Mia40 that is able to recognize substrates with apparently little or no homology. Following substrate oxidation, Mia40 is reduced and must be reoxidized by Erv1/Alr1 that consequently transfers the electrons to the mitochondrial respiratory chain. Although our understanding of the physiological relevance of this process is still limited, an increasing number of pathologies are being associated with the impairment of this pathway; especially because oxidative folding is fundamental for several of the proteins involved in defense against oxidative stress. Here we review these aspects and discuss recent findings suggesting that oxidative folding in the IMS is modulated by the redox state of the cell.
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Affiliation(s)
- Hugo Fraga
- Department of Biochemistry and Molecular Biology, Autonomous University of Barcelona, Bellaterra E-08193, Spain
- Authors to whom correspondence should be addressed; E-Mails: (H.F.); (S.V.); Tel.: +34-93-581-2154 (H.F.); +34-93-586-8956 (S.V.); Fax: +34-93-581-1264 (H.F. & S.V.)
| | - Salvador Ventura
- Department of Biochemistry and Molecular Biology, Autonomous University of Barcelona, Bellaterra E-08193, Spain
- Institute of Biotechnology and Biomedicine, Autonomous University of Barcelona, Bellaterra E-08193, Spain
- Authors to whom correspondence should be addressed; E-Mails: (H.F.); (S.V.); Tel.: +34-93-581-2154 (H.F.); +34-93-586-8956 (S.V.); Fax: +34-93-581-1264 (H.F. & S.V.)
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30
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Divergence of Erv1-associated mitochondrial import and export pathways in trypanosomes and anaerobic protists. EUKARYOTIC CELL 2012; 12:343-55. [PMID: 23264646 DOI: 10.1128/ec.00304-12] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In yeast (Saccharomyces cerevisiae) and animals, the sulfhydryl oxidase Erv1 functions with Mia40 in the import and oxidative folding of numerous cysteine-rich proteins in the mitochondrial intermembrane space (IMS). Erv1 is also required for Fe-S cluster assembly in the cytosol, which uses at least one mitochondrially derived precursor. Here, we characterize an essential Erv1 orthologue from the protist Trypanosoma brucei (TbERV1), which naturally lacks a Mia40 homolog. We report kinetic parameters for physiologically relevant oxidants cytochrome c and O(2), unexpectedly find O(2) and cytochrome c are reduced simultaneously, and demonstrate that efficient reduction of O(2) by TbERV1 is not dependent upon a simple O(2) channel defined by conserved histidine and tyrosine residues. Massive mitochondrial swelling following TbERV1 RNA interference (RNAi) provides evidence that trypanosome Erv1 functions in IMS protein import despite the natural absence of the key player in the yeast and animal import pathways, Mia40. This suggests significant evolutionary divergence from a recently established paradigm in mitochondrial cell biology. Phylogenomic profiling of genes also points to a conserved role for TbERV1 in cytosolic Fe-S cluster assembly. Conversely, loss of genes implicated in precursor delivery for cytosolic Fe-S assembly in Entamoeba, Trichomonas, and Giardia suggests fundamental differences in intracellular trafficking pathways for activated iron or sulfur species in anaerobic versus aerobic eukaryotes.
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31
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Sztolsztener ME, Brewinska A, Guiard B, Chacinska A. Disulfide bond formation: sulfhydryl oxidase ALR controls mitochondrial biogenesis of human MIA40. Traffic 2012. [PMID: 23186364 DOI: 10.1111/tra.12030] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The conserved MIA pathway is responsible for the import and oxidative folding of proteins destined for the intermembrane space of mitochondria. In contrast to a wealth of information obtained from studies with yeast, the function of the MIA pathway in higher eukaryotes has remained enigmatic. Here, we took advantage of the molecular understanding of the MIA pathway in yeast and designed a model of the human MIA pathway. The yeast model for MIA consists of two critical components, the disulfide bond carrier Mia40 and sulfhydryl oxidase Erv1/ALR. Human MIA40 and ALR substituted for their yeast counterparts in the essential function for the oxidative biogenesis of mitochondrial intermembrane space proteins. In addition, the sulfhydryl oxidases ALR/Erv1 were found to be involved in the mitochondrial localization of human MIA40. Furthermore, the defective accumulation of human MIA40 in mitochondria underlies a recently identified disease that is caused by amino acid exchange in ALR. Thus, human ALR is an important factor that controls not only the ability of MIA40 to bind and oxidize protein clients but also the localization of human MIA40 in mitochondria.
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Affiliation(s)
- Malgorzata E Sztolsztener
- International Institute of Molecular and Cell Biology, Laboratory of Mitochondrial Biogenesis Warsaw, 02-109, Poland
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32
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Eckers E, Petrungaro C, Gross D, Riemer J, Hell K, Deponte M. Divergent molecular evolution of the mitochondrial sulfhydryl:cytochrome C oxidoreductase Erv in opisthokonts and parasitic protists. J Biol Chem 2012; 288:2676-88. [PMID: 23233680 DOI: 10.1074/jbc.m112.420745] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mia40 and the sulfhydryl:cytochrome c oxidoreductase Erv1/ALR are essential for oxidative protein import into the mitochondrial intermembrane space in yeast and mammals. Although mitochondrial protein import is functionally conserved in the course of evolution, many organisms seem to lack Mia40. Moreover, except for in organello import studies and in silico analyses, nothing is known about the function and properties of protist Erv homologues. Here we compared Erv homologues from yeast, the kinetoplastid parasite Leishmania tarentolae, and the non-related malaria parasite Plasmodium falciparum. Both parasite proteins have altered cysteine motifs, formed intermolecular disulfide bonds in vitro and in vivo, and could not replace Erv1 from yeast despite successful mitochondrial protein import in vivo. To analyze its enzymatic activity, we established the expression and purification of recombinant full-length L. tarentolae Erv and compared the mechanism with related and non-related flavoproteins. Enzyme assays indeed confirmed an electron transferase activity with equine and yeast cytochrome c, suggesting a conservation of the enzymatic activity in different eukaryotic lineages. However, although Erv and non-related flavoproteins are intriguing examples of convergent molecular evolution resulting in similar enzyme properties, the mechanisms of Erv homologues from parasitic protists and opisthokonts differ significantly. In summary, the Erv-mediated reduction of cytochrome c might be highly conserved throughout evolution despite the apparent absence of Mia40 in many eukaryotes. Nevertheless, the knowledge on mitochondrial protein import in yeast and mammals cannot be generally transferred to all other eukaryotes, and the corresponding pathways, components, and mechanisms remain to be analyzed.
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Affiliation(s)
- Elisabeth Eckers
- Department of Parasitology, Ruprecht-Karls University, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany
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Schaefer SA, Dong M, Rubenstein RP, Wilkie WA, Bahnson BJ, Thorpe C, Rozovsky S. (77)Se enrichment of proteins expands the biological NMR toolbox. J Mol Biol 2012; 425:222-31. [PMID: 23159557 DOI: 10.1016/j.jmb.2012.11.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 11/06/2012] [Accepted: 11/07/2012] [Indexed: 10/27/2022]
Abstract
Sulfur, a key contributor to biological reactivity, is not amendable to investigations by biological NMR spectroscopy. To utilize selenium as a surrogate, we have developed a generally applicable (77)Se isotopic enrichment method for heterologous proteins expressed in Escherichia coli. We demonstrate (77)Se NMR spectroscopy of multiple selenocysteine and selenomethionine residues in the sulfhydryl oxidase augmenter of liver regeneration (ALR). The resonances of the active-site residues were assigned by comparing the NMR spectra of ALR bound to oxidized and reduced flavin adenine dinucleotide. An additional resonance appears only in the presence of the reducing agent and disappears readily upon exposure to air and subsequent reoxidation of the flavin. Hence, (77)Se NMR spectroscopy can be used to report the local electronic environment of reactive and structural sulfur sites, as well as changes taking place in those locations during catalysis.
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Affiliation(s)
- Stephanie A Schaefer
- 136 Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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34
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Guo PC, Ma JD, Jiang YL, Wang SJ, Bao ZZ, Yu XJ, Chen Y, Zhou CZ. Structure of yeast sulfhydryl oxidase erv1 reveals electron transfer of the disulfide relay system in the mitochondrial intermembrane space. J Biol Chem 2012; 287:34961-34969. [PMID: 22910915 DOI: 10.1074/jbc.m112.394759] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The disulfide relay system in the mitochondrial intermembrane space drives the import of proteins with twin CX(9)C or twin CX(3)C motifs by an oxidative folding mechanism. This process requires disulfide bond transfer from oxidized Mia40 to a substrate protein. Reduced Mia40 is reoxidized/regenerated by the FAD-linked sulfhydryl oxidase Erv1 (EC 1.8.3.2). Full-length Erv1 consists of a flexible N-terminal shuttle domain (NTD) and a conserved C-terminal core domain (CTD). Here, we present crystal structures at 2.0 Å resolution of the CTD and at 3.0 Å resolution of a C30S/C133S double mutant of full-length Erv1 (Erv1FL). Similar to previous homologous structures, the CTD exists as a homodimer, with each subunit consisting of a conserved four-helix bundle that accommodates the isoalloxazine ring of FAD and an additional single-turn helix. The structure of Erv1FL enabled us to identify, for the first time, the three-dimensional structure of the Erv1NTD, which is an amphipathic helix flanked by two flexible loops. This structure also represents an intermediate state of electron transfer from the NTD to the CTD of another subunit. Comparative structural analysis revealed that the four-helix bundle of the CTD forms a wide platform for the electron donor NTD. Moreover, computational simulation combined with multiple-sequence alignment suggested that the amphipathic helix close to the shuttle redox enter is critical for the recognition of Mia40, the upstream electron donor. These findings provide structural insights into electron transfer from Mia40 via the shuttle domain of one subunit of Erv1 to the CTD of another Erv1 subunit.
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Affiliation(s)
- Peng-Chao Guo
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Jin-Di Ma
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Yong-Liang Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Shu-Jie Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Zhang-Zhi Bao
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Xiao-Jie Yu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Yuxing Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China
| | - Cong-Zhao Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230027, China.
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Kallergi E, Andreadaki M, Kritsiligkou P, Katrakili N, Pozidis C, Tokatlidis K, Banci L, Bertini I, Cefaro C, Ciofi-Baffoni S, Gajda K, Peruzzini R. Targeting and maturation of Erv1/ALR in the mitochondrial intermembrane space. ACS Chem Biol 2012; 7:707-14. [PMID: 22296668 DOI: 10.1021/cb200485b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interaction of Mia40 with Erv1/ALR is central to the oxidative protein folding in the intermembrane space of mitochondria (IMS) as Erv1/ALR oxidizes reduced Mia40 to restore its functional state. Here we address the role of Mia40 in the import and maturation of Erv1/ALR. The C-terminal FAD-binding domain of Erv1/ALR has an essential role in the import process by creating a transient intermolecular disulfide bond with Mia40. The action of Mia40 is selective for the formation of both intra and intersubunit structural disulfide bonds of Erv1/ALR, but the complete maturation process requires additional binding of FAD. Both of these events must follow a specific sequential order to allow Erv1/ALR to reach the fully functional state, illustrating a new paradigm for protein maturation in the IMS.
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Affiliation(s)
- Emmanouela Kallergi
- Institute of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion 71110, Crete, Greece
- Department of Biology, University of Crete, Heraklion 71409, Crete, Greece
| | - Maria Andreadaki
- Institute of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion 71110, Crete, Greece
- Department of Biology, University of Crete, Heraklion 71409, Crete, Greece
| | - Paraskevi Kritsiligkou
- Institute of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion 71110, Crete, Greece
- Department of Biology, University of Crete, Heraklion 71409, Crete, Greece
| | - Nitsa Katrakili
- Institute of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion 71110, Crete, Greece
| | - Charalambos Pozidis
- Institute of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion 71110, Crete, Greece
| | - Kostas Tokatlidis
- Institute of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion 71110, Crete, Greece
- Department of Materials Science
and Technology, University of Crete, Heraklion
71003, Crete, Greece
| | - Lucia Banci
- Magnetic
Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019
Sesto Fiorentino, Florence, Italy
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019
Sesto Fiorentino, Florence, Italy
| | - Ivano Bertini
- Magnetic
Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019
Sesto Fiorentino, Florence, Italy
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019
Sesto Fiorentino, Florence, Italy
| | - Chiara Cefaro
- Magnetic
Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019
Sesto Fiorentino, Florence, Italy
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019
Sesto Fiorentino, Florence, Italy
| | - Simone Ciofi-Baffoni
- Magnetic
Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019
Sesto Fiorentino, Florence, Italy
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019
Sesto Fiorentino, Florence, Italy
| | - Karolina Gajda
- Magnetic
Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019
Sesto Fiorentino, Florence, Italy
| | - Riccardo Peruzzini
- Magnetic
Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019
Sesto Fiorentino, Florence, Italy
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36
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Sevier CS. Erv2 and quiescin sulfhydryl oxidases: Erv-domain enzymes associated with the secretory pathway. Antioxid Redox Signal 2012; 16:800-8. [PMID: 22142242 DOI: 10.1089/ars.2011.4450] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
SIGNIFICANCE Members of the Erv/ALR/QSOX protein family contain an Erv sequence module and catalyze protein disulfide bond formation. Erv enzymes impact protein function within and outside cells that affects both normal and malignant cell growth. This protein family is named for its founding members: Erv1 (essential for respiratory and vegetative growth 1) and ALR (augmenter of liver regeneration), homologous mitochondrial proteins from yeast and mammals, respectively, and QSOX (quiescin sulfhydryl oxidase), an oxidase secreted from quiescent cells. This review will focus on a subset of Erv proteins that are localized within the secretory pathway: Erv2-like proteins, proteins present in the endoplasmic reticulum of fungi, and QSOX proteins, proteins localized within the secretory pathway and extracellular space and present in most eukaryotes, but not fungi. RECENT ADVANCES A wealth of structural and biochemical data has been obtained for Erv2 and QSOX proteins. These data have identified a generally conserved catalytic mechanism and structure for the Erv2 and QSOX proteins with unique features for each enzyme. CRITICAL ISSUES Many fundamental questions remain about the activity for these proteins in living cells including the partners, pathways, and locations utilized by these enzymes in vivo. FUTURE DIRECTIONS A more comprehensive understanding of the cellular roles for Erv2 and QSOX enzymes will require identification of their partners and substrates. Also, determining when Erv2 and QSOX function during growth and development, and how changes in levels of active Erv2 and QSOX impact cell function, is necessary to facilitate a better understanding of these intriguing enzymes.
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Affiliation(s)
- Carolyn S Sevier
- Department of Molecular Medicine, Cornell University, Ithaca, New York 14853, USA.
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37
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Li Y, Farooq M, Sheng D, Chandramouli C, Lan T, Mahajan NK, Kini RM, Hong Y, Lisowsky T, Ge R. Augmenter of liver regeneration (alr) promotes liver outgrowth during zebrafish hepatogenesis. PLoS One 2012; 7:e30835. [PMID: 22292055 PMCID: PMC3266923 DOI: 10.1371/journal.pone.0030835] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 12/29/2011] [Indexed: 02/06/2023] Open
Abstract
Augmenter of Liver Regeneration (ALR) is a sulfhydryl oxidase carrying out fundamental functions facilitating protein disulfide bond formation. In mammals, it also functions as a hepatotrophic growth factor that specifically stimulates hepatocyte proliferation and promotes liver regeneration after liver damage or partial hepatectomy. Whether ALR also plays a role during vertebrate hepatogenesis is unknown. In this work, we investigated the function of alr in liver organogenesis in zebrafish model. We showed that alr is expressed in liver throughout hepatogenesis. Knockdown of alr through morpholino antisense oligonucleotide (MO) leads to suppression of liver outgrowth while overexpression of alr promotes liver growth. The small-liver phenotype in alr morphants results from a reduction of hepatocyte proliferation without affecting apoptosis. When expressed in cultured cells, zebrafish Alr exists as dimer and is localized in mitochondria as well as cytosol but not in nucleus or secreted outside of the cell. Similar to mammalian ALR, zebrafish Alr is a flavin-linked sulfhydryl oxidase and mutation of the conserved cysteine in the CxxC motif abolishes its enzymatic activity. Interestingly, overexpression of either wild type Alr or enzyme-inactive Alr(C131S) mutant promoted liver growth and rescued the liver growth defect of alr morphants. Nevertheless, alr(C131S) is less efficacious in both functions. Meantime, high doses of alr MOs lead to widespread developmental defects and early embryonic death in an alr sequence-dependent manner. These results suggest that alr promotes zebrafish liver outgrowth using mechanisms that are dependent as well as independent of its sulfhydryl oxidase activity. This is the first demonstration of a developmental role of alr in vertebrate. It exemplifies that a low-level sulfhydryl oxidase activity of Alr is essential for embryonic development and cellular survival. The dose-dependent and partial suppression of alr expression through MO-mediated knockdown allows the identification of its late developmental role in vertebrate liver organogenesis.
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Affiliation(s)
- Yan Li
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Muhammad Farooq
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Zoology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Donglai Sheng
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Chanchal Chandramouli
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Tian Lan
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Nilesh K. Mahajan
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - R. Manjunatha Kini
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Biochemistry and Molecular Biology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Yunhan Hong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | | | - Ruowen Ge
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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38
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Banci L, Bertini I, Calderone V, Cefaro C, Ciofi-Baffoni S, Gallo A, Tokatlidis K. An Electron-Transfer Path through an Extended Disulfide Relay System: The Case of the Redox Protein ALR. J Am Chem Soc 2012; 134:1442-5. [DOI: 10.1021/ja209881f] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center, University of Florence, via L. Sacconi 6, Sesto Fiorentino,
Italy
- Department of Chemistry, University of Florence, via della Lastruccia 3, Sesto
Fiorentino, Italy
| | - Ivano Bertini
- Magnetic Resonance Center, University of Florence, via L. Sacconi 6, Sesto Fiorentino,
Italy
- Department of Chemistry, University of Florence, via della Lastruccia 3, Sesto
Fiorentino, Italy
| | - Vito Calderone
- Magnetic Resonance Center, University of Florence, via L. Sacconi 6, Sesto Fiorentino,
Italy
- Department of Chemistry, University of Florence, via della Lastruccia 3, Sesto
Fiorentino, Italy
| | - Chiara Cefaro
- Magnetic Resonance Center, University of Florence, via L. Sacconi 6, Sesto Fiorentino,
Italy
- Department of Chemistry, University of Florence, via della Lastruccia 3, Sesto
Fiorentino, Italy
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center, University of Florence, via L. Sacconi 6, Sesto Fiorentino,
Italy
- Department of Chemistry, University of Florence, via della Lastruccia 3, Sesto
Fiorentino, Italy
| | - Angelo Gallo
- Magnetic Resonance Center, University of Florence, via L. Sacconi 6, Sesto Fiorentino,
Italy
- Department of Chemistry, University of Florence, via della Lastruccia 3, Sesto
Fiorentino, Italy
| | - Kostas Tokatlidis
- Institute
of Molecular Biology
and Biotechnology, Foundation for Research and Technology Hellas, Heraklion 70013, Crete, Greece
- Department of Materials Science
and Technology, University of Crete, Heraklion
71003, Crete, Greece
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39
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Daithankar VN, Wang W, Trujillo JR, Thorpe C. Flavin-linked Erv-family sulfhydryl oxidases release superoxide anion during catalytic turnover. Biochemistry 2011; 51:265-72. [PMID: 22148553 DOI: 10.1021/bi201672h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Typically, simple flavoprotein oxidases couple the oxidation of their substrates with the formation of hydrogen peroxide without release of significant levels of the superoxide ion. However, two evolutionarily related single-domain sulfhydryl oxidases (Erv2p; a yeast endoplasmic reticulum resident protein and augmenter of liver regeneration, ALR, an enzyme predominantly found in the mitochondrial intermembrane) release up to ~30% of the oxygen they reduce as the superoxide ion. Both enzymes oxidize dithiol substrates via a redox-active disulfide adjacent to the flavin cofactor within the helix-rich Erv domain. Subsequent reduction of the flavin is followed by transfer of reducing equivalents to molecular oxygen. Superoxide release was initially detected using tris(3-hydroxypropyl)phosphine (THP) as an alternative reducing substrate to dithiothreitol (DTT). THP, and other phosphines, showed anomalously high turnover numbers with Erv2p and ALR in the oxygen electrode, but oxygen consumption was drastically suppressed upon the addition of superoxide dismutase. The superoxide ion initiates a radical chain reaction promoting the aerobic oxidation of phosphines with the formation of hydrogen peroxide. Use of a known flux of superoxide generated by the xanthine/xanthine oxidase system showed that one superoxide ion stimulates the reduction of 27 and 4.5 molecules of oxygen using THP and tris(2-carboxyethyl)phosphine (TCEP), respectively. This superoxide-dependent amplification of oxygen consumption by phosphines provides a new kinetic method for the detection of superoxide. Superoxide release was also observed by a standard chemiluminescence method using a luciferin analogue (MCLA) when 2 mM DTT was employed as a substrate of Erv2p and ALR. The percentage of superoxide released from Erv2p increased to ~65% when monomeric mutants of the normally homodimeric enzyme were used. In contrast, monomeric multidomain quiescin sulfhydryl oxidase enzymes that also contain an Erv FAD-binding fold release only 1-5% of their total reduced oxygen species as the superoxide ion. Aspects of the mechanism and possible physiological significance of superoxide release from these Erv-domain flavoproteins are discussed.
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Affiliation(s)
- Vidyadhar N Daithankar
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716-2522, United States
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40
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Herrmann JM, Riemer J. Mitochondrial disulfide relay: redox-regulated protein import into the intermembrane space. J Biol Chem 2011; 287:4426-33. [PMID: 22157015 DOI: 10.1074/jbc.r111.270678] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
99% of all mitochondrial proteins are synthesized in the cytosol, from where they are imported into mitochondria. In contrast to matrix proteins, many proteins of the intermembrane space (IMS) lack presequences and are imported in an oxidation-driven reaction by the mitochondrial disulfide relay. Incoming polypeptides are recognized and oxidized by the IMS-located receptor Mia40. Reoxidation of Mia40 is facilitated by the sulfhydryl oxidase Erv1 and the respiratory chain. Although structurally unrelated, the mitochondrial disulfide relay functionally resembles the Dsb (disufide bond) system of the bacterial periplasm, the compartment from which the IMS was derived 2 billion years ago.
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Affiliation(s)
- Johannes M Herrmann
- Department of Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany.
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41
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Structure of a baculovirus sulfhydryl oxidase, a highly divergent member of the erv flavoenzyme family. J Virol 2011; 85:9406-13. [PMID: 21752922 DOI: 10.1128/jvi.05149-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Genomes of nucleocytoplasmic large DNA viruses (NCLDVs) encode enzymes that catalyze the formation of disulfide bonds between cysteine amino acid residues in proteins, a function essential for the proper assembly and propagation of NCLDV virions. Recently, a catalyst of disulfide formation was identified in baculoviruses, a group of large double-stranded DNA viruses considered phylogenetically distinct from NCLDVs. The NCLDV and baculovirus disulfide catalysts are flavin adenine dinucleotide (FAD)-binding sulfhydryl oxidases related to the cellular Erv enzyme family, but the baculovirus enzyme, the product of the Ac92 gene in Autographa californica multiple nucleopolyhedrovirus (AcMNPV), is highly divergent at the amino acid sequence level. The crystal structure of the Ac92 protein presented here shows a configuration of the active-site cysteine residues and bound cofactor similar to that observed in other Erv sulfhydryl oxidases. However, Ac92 has a complex quaternary structural arrangement not previously seen in cellular or viral enzymes of this family. This novel assembly comprises a dimer of pseudodimers with a striking 40-degree kink in the interface helix between subunits. The diversification of the Erv sulfhydryl oxidase enzymes in large double-stranded DNA viruses exemplifies the extreme degree to which these viruses can push the boundaries of protein family folds.
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42
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Faccio G, Nivala O, Kruus K, Buchert J, Saloheimo M. Sulfhydryl oxidases: sources, properties, production and applications. Appl Microbiol Biotechnol 2011; 91:957-66. [DOI: 10.1007/s00253-011-3440-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/10/2011] [Accepted: 06/11/2011] [Indexed: 01/24/2023]
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43
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Molecular recognition and substrate mimicry drive the electron-transfer process between MIA40 and ALR. Proc Natl Acad Sci U S A 2011; 108:4811-6. [PMID: 21383138 DOI: 10.1073/pnas.1014542108] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oxidative protein folding in the mitochondrial intermembrane space requires the transfer of a disulfide bond from MIA40 to the substrate. During this process MIA40 is reduced and regenerated to a functional state through the interaction with the flavin-dependent sulfhydryl oxidase ALR. Here we present the mechanistic basis of ALR-MIA40 interaction at atomic resolution by biochemical and structural analyses of the mitochondrial ALR isoform and its covalent mixed disulfide intermediate with MIA40. This ALR isoform contains a folded FAD-binding domain at the C-terminus and an unstructured, flexible N-terminal domain, weakly and transiently interacting one with the other. A specific region of the N-terminal domain guides the interaction with the MIA40 substrate binding cleft (mimicking the interaction of the substrate itself), without being involved in the import of ALR. The hydrophobicity-driven binding of this region ensures precise protein-protein recognition needed for an efficient electron transfer process.
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