1
|
Bell M, Kane MS, Ouyang X, Young ME, Jegga AG, Chatham JC, Darley-Usmar V, Zhang J. Acute increase of protein O-GlcNAcylation in mice leads to transcriptome changes in the brain opposite to what is observed in Alzheimer's Disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.19.613769. [PMID: 39345543 PMCID: PMC11429956 DOI: 10.1101/2024.09.19.613769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
Enhancing protein O-GlcNAcylation by pharmacological inhibition of the enzyme O-GlcNAcase (OGA) is explored as a strategy to decrease tau and amyloid-beta phosphorylation, aggregation, and pathology in Alzheimer's disease (AD). There is still more to be learned about the impact of enhancing global protein O-GlcNAcylation, which is important for understanding the mechanistic path of using OGA inhibition to treat AD. In this study, we investigated the acute effect of pharmacologically increasing O-GlcNAc levels, using OGA inhibitor Thiamet G (TG), on normal mouse brains. We hypothesized that the transcritome signature in respones to TG treatment provides a comprehensive view of the effect of OGA inhibition. We sacrificed the mice and dissected their brains after 3 hours of saline or 50 mg/kg TG treatment, and then performed mRNA sequencing using NovaSeq PE 150 (n=5 each group). We identified 1,234 significant differentially expressed genes with TG versus saline treatment. Functional enrichment analysis of the upregulated genes identified several upregulated pathways, including genes normally down in AD. Among the downregulated pathways were the cell adhesion pathway as well as genes normally up in AD and aging. When comparing acute to chronic TG treatment, protein autophosphorylation and kinase activity pathways were upregulated, whereas cell adhesion and astrocyte markers were downregulated in both datasets. Interestingly, mitochondrial genes and genes normally down in AD were up in acute treatment and down in chronic treatment. Data from this analysis will enable the evaluation of the mechanisms underlying the potential benefits of OGA inhibition in the treatment of AD. In particular, although OGA inhibitors are promising to treat AD, their downstream chronic effects related to bioenergetics may be a limiting factor. Abstract Figure
Collapse
|
2
|
Paquay S, Duraffourd J, Bury M, Heremans IP, Caligiore F, Gerin I, Stroobant V, Jacobs J, Pinon A, Graff J, Vertommen D, Van Schaftingen E, Dewulf JP, Bommer GT. ACAD10 and ACAD11 allow entry of 4-hydroxy fatty acids into β-oxidation. Cell Mol Life Sci 2024; 81:367. [PMID: 39174697 PMCID: PMC11342911 DOI: 10.1007/s00018-024-05397-8] [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: 04/27/2024] [Revised: 08/02/2024] [Accepted: 08/05/2024] [Indexed: 08/24/2024]
Abstract
Hydroxylated fatty acids are important intermediates in lipid metabolism and signaling. Surprisingly, the metabolism of 4-hydroxy fatty acids remains largely unexplored. We found that both ACAD10 and ACAD11 unite two enzymatic activities to introduce these metabolites into mitochondrial and peroxisomal β-oxidation, respectively. First, they phosphorylate 4-hydroxyacyl-CoAs via a kinase domain, followed by an elimination of the phosphate to form enoyl-CoAs catalyzed by an acyl-CoA dehydrogenase (ACAD) domain. Studies in knockout cell lines revealed that ACAD10 preferentially metabolizes shorter chain 4-hydroxy fatty acids than ACAD11 (i.e. 6 carbons versus 10 carbons). Yet, recombinant proteins showed comparable activity on the corresponding 4-hydroxyacyl-CoAs. This suggests that the localization of ACAD10 and ACAD11 to mitochondria and peroxisomes, respectively, might influence their physiological substrate spectrum. Interestingly, we observed that ACAD10 is cleaved internally during its maturation generating a C-terminal part consisting of the ACAD domain, and an N-terminal part comprising the kinase domain and a haloacid dehalogenase (HAD) domain. HAD domains often exhibit phosphatase activity, but negligible activity was observed in the case of ACAD10. Yet, inactivation of a presumptive key residue in this domain significantly increased the kinase activity, suggesting that this domain might have acquired a regulatory function to prevent accumulation of the phospho-hydroxyacyl-CoA intermediate. Taken together, our work reveals that 4-hydroxy fatty acids enter mitochondrial and peroxisomal fatty acid β-oxidation via two enzymes with an overlapping substrate repertoire.
Collapse
Affiliation(s)
- Stéphanie Paquay
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
- Department of Pediatric Neurology and Metabolic Diseases, Cliniques Universitaires St. Luc, Université Catholique de Louvain, 1200, Brussels, Belgium
| | - Julia Duraffourd
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Marina Bury
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Isaac P Heremans
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Francesco Caligiore
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Isabelle Gerin
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | | | - Jean Jacobs
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Aymeric Pinon
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Julie Graff
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Didier Vertommen
- Protein Phosphorylation Unit, de Duve Institute & MASSPROT Platform, Université Catholique de Louvain, 1200, Brussels, Belgium
| | - Emile Van Schaftingen
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Joseph P Dewulf
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
- Department of Laboratory Medicine, Cliniques Universitaires St. Luc, Université Catholique de Louvain, 1200, Brussels, Belgium
| | - Guido T Bommer
- Metabolic Research Group, de Duve Institute & WELRI, Université Catholique de Louvain, 1200, Brussels, Belgium.
- WELBIO Department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium.
| |
Collapse
|
3
|
Karpov OA, Stotland A, Raedschelders K, Chazarin B, Ai L, Murray CI, Van Eyk JE. Proteomics of the heart. Physiol Rev 2024; 104:931-982. [PMID: 38300522 PMCID: PMC11381016 DOI: 10.1152/physrev.00026.2023] [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: 07/03/2023] [Revised: 12/25/2023] [Accepted: 01/14/2024] [Indexed: 02/02/2024] Open
Abstract
Mass spectrometry-based proteomics is a sophisticated identification tool specializing in portraying protein dynamics at a molecular level. Proteomics provides biologists with a snapshot of context-dependent protein and proteoform expression, structural conformations, dynamic turnover, and protein-protein interactions. Cardiac proteomics can offer a broader and deeper understanding of the molecular mechanisms that underscore cardiovascular disease, and it is foundational to the development of future therapeutic interventions. This review encapsulates the evolution, current technologies, and future perspectives of proteomic-based mass spectrometry as it applies to the study of the heart. Key technological advancements have allowed researchers to study proteomes at a single-cell level and employ robot-assisted automation systems for enhanced sample preparation techniques, and the increase in fidelity of the mass spectrometers has allowed for the unambiguous identification of numerous dynamic posttranslational modifications. Animal models of cardiovascular disease, ranging from early animal experiments to current sophisticated models of heart failure with preserved ejection fraction, have provided the tools to study a challenging organ in the laboratory. Further technological development will pave the way for the implementation of proteomics even closer within the clinical setting, allowing not only scientists but also patients to benefit from an understanding of protein interplay as it relates to cardiac disease physiology.
Collapse
Affiliation(s)
- Oleg A Karpov
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Aleksandr Stotland
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Koen Raedschelders
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Blandine Chazarin
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Lizhuo Ai
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Christopher I Murray
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Jennifer E Van Eyk
- Smidt Heart Institute, Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| |
Collapse
|
4
|
Grba DN, Wright JJ, Yin Z, Fisher W, Hirst J. Molecular mechanism of the ischemia-induced regulatory switch in mammalian complex I. Science 2024; 384:1247-1253. [PMID: 38870289 DOI: 10.1126/science.ado2075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/01/2024] [Indexed: 06/15/2024]
Abstract
Respiratory complex I is an efficient driver for oxidative phosphorylation in mammalian mitochondria, but its uncontrolled catalysis under challenging conditions leads to oxidative stress and cellular damage. Ischemic conditions switch complex I from rapid, reversible catalysis into a dormant state that protects upon reoxygenation, but the molecular basis for the switch is unknown. We combined precise biochemical definition of complex I catalysis with high-resolution cryo-electron microscopy structures in the phospholipid bilayer of coupled vesicles to reveal the mechanism of the transition into the dormant state, modulated by membrane interactions. By implementing a versatile membrane system to unite structure and function, attributing catalytic and regulatory properties to specific structural states, we define how a conformational switch in complex I controls its physiological roles.
Collapse
Affiliation(s)
| | | | | | | | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| |
Collapse
|
5
|
Dieckmann CL. A hub for regulation of mitochondrial metabolism: Fatty acid and lipoic acid biosynthesis. IUBMB Life 2024; 76:332-344. [PMID: 38088214 DOI: 10.1002/iub.2802] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/21/2023] [Indexed: 05/28/2024]
Abstract
Having evolved from a prokaryotic origin, mitochondria retain pathways required for the catabolism of energy-rich molecules and for the biosynthesis of molecules that aid catabolism and/or participate in other cellular processes essential for life of the cell. Reviewed here are details of the mitochondrial fatty acid biosynthetic pathway (FAS II) and its role in building both the octanoic acid precursor for lipoic acid biosynthesis (LAS) and longer-chain fatty acids functioning in chaperoning the assembly of mitochondrial multisubunit complexes. Also covered are the details of mitochondrial lipoic acid biosynthesis, which is distinct from that of prokaryotes, and the attachment of lipoic acid to subunits of pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and glycine cleavage system complexes. Special emphasis has been placed on presenting what is currently known about the interconnected paths and loops linking the FAS II-LAS pathway and two other mitochondrial realms, the organellar translation machinery and Fe-S cluster biosynthesis and function.
Collapse
Affiliation(s)
- Carol L Dieckmann
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| |
Collapse
|
6
|
Jimenez-Blasco D, Almeida A, Bolaños JP. Brightness and shadows of mitochondrial ROS in the brain. Neurobiol Dis 2023:106199. [PMID: 37321421 DOI: 10.1016/j.nbd.2023.106199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023] Open
Abstract
Mitochondrial reactive oxygen species (mROS) have been generally considered harmful byproducts wanted to clear when elevated to avoid brain damage. However, the abundance of mROS in astrocytes is very high -about one order of magnitude above that in neurons-, despite they are essential to preserve cell metabolism and animal behavior. Here, we have focused on this apparent ambiguity by discussing (i) the intrinsic mechanisms accounting for the higher production of mROS by the mitochondrial respiratory chain in astrocytes than in neurons, (ii) the specific molecular targets of astrocytic beneficial mROS, and (iii) how decreased astrocytic mROS causes excess neuronal mROS leading to cellular and organismal damage. We hope that this mini-review serves to clarifying the apparent controversy on the beneficial versus deleterious faces of ROS in the brain from molecular to higher-order organismal levels.
Collapse
Affiliation(s)
- Daniel Jimenez-Blasco
- Instituto de Biología Funcional y Genómica (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain.
| | - Angeles Almeida
- Instituto de Biología Funcional y Genómica (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain.
| | - Juan P Bolaños
- Instituto de Biología Funcional y Genómica (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain.
| |
Collapse
|
7
|
Liang Y, Plourde A, Bueler SA, Liu J, Brzezinski P, Vahidi S, Rubinstein JL. Structure of mycobacterial respiratory complex I. Proc Natl Acad Sci U S A 2023; 120:e2214949120. [PMID: 36952383 PMCID: PMC10068793 DOI: 10.1073/pnas.2214949120] [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: 09/04/2022] [Accepted: 02/10/2023] [Indexed: 03/24/2023] Open
Abstract
Oxidative phosphorylation, the combined activity of the electron transport chain (ETC) and adenosine triphosphate synthase, has emerged as a valuable target for the treatment of infection by Mycobacterium tuberculosis and other mycobacteria. The mycobacterial ETC is highly branched with multiple dehydrogenases transferring electrons to a membrane-bound pool of menaquinone and multiple oxidases transferring electrons from the pool. The proton-pumping type I nicotinamide adenine dinucleotide (NADH) dehydrogenase (Complex I) is found in low abundance in the plasma membranes of mycobacteria in typical in vitro culture conditions and is often considered dispensable. We found that growth of Mycobacterium smegmatis in carbon-limited conditions greatly increased the abundance of Complex I and allowed isolation of a rotenone-sensitive preparation of the enzyme. Determination of the structure of the complex by cryoEM revealed the "orphan" two-component response regulator protein MSMEG_2064 as a subunit of the assembly. MSMEG_2064 in the complex occupies a site similar to the proposed redox-sensing subunit NDUFA9 in eukaryotic Complex I. An apparent purine nucleoside triphosphate within the NuoG subunit resembles the GTP-derived molybdenum cofactor in homologous formate dehydrogenase enzymes. The membrane region of the complex binds acyl phosphatidylinositol dimannoside, a characteristic three-tailed lipid from the mycobacterial membrane. The structure also shows menaquinone, which is preferentially used over ubiquinone by gram-positive bacteria, in two different positions along the quinone channel, comparable to ubiquinone in other structures and suggesting a conserved quinone binding mechanism.
Collapse
Affiliation(s)
- Yingke Liang
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, TorontoM5S 1A8, Canada
| | - Alicia Plourde
- Department of Molecular and Cellular Biology, University of Guelph, TorontoN1G 2W1, Canada
| | - Stephanie A. Bueler
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
| | - Jun Liu
- Department of Molecular Genetics, University of Toronto, TorontoM5S 1A8, Canada
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91Stockholm, Sweden
| | - Siavash Vahidi
- Department of Molecular and Cellular Biology, University of Guelph, TorontoN1G 2W1, Canada
| | - John L. Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, TorontoM5S 1A8, Canada
- Department of Medical Biophysics, University of Toronto, TorontoM5G 1L7, Canada
| |
Collapse
|
8
|
Rahman MT, Koski MK, Panecka-Hofman J, Schmitz W, Kastaniotis AJ, Wade RC, Wierenga RK, Hiltunen JK, Autio KJ. An engineered variant of MECR reductase reveals indispensability of long-chain acyl-ACPs for mitochondrial respiration. Nat Commun 2023; 14:619. [PMID: 36739436 PMCID: PMC9899272 DOI: 10.1038/s41467-023-36358-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 01/25/2023] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial fatty acid synthesis (mtFAS) is essential for respiratory function. MtFAS generates the octanoic acid precursor for lipoic acid synthesis, but the role of longer fatty acid products has remained unclear. The structurally well-characterized component of mtFAS, human 2E-enoyl-ACP reductase (MECR) rescues respiratory growth and lipoylation defects of a Saccharomyces cerevisiae Δetr1 strain lacking native mtFAS enoyl reductase. To address the role of longer products of mtFAS, we employed in silico molecular simulations to design a MECR variant with a shortened substrate binding cavity. Our in vitro and in vivo analyses indicate that the MECR G165Q variant allows synthesis of octanoyl groups but not long chain fatty acids, confirming the validity of our computational approach to engineer substrate length specificity. Furthermore, our data imply that restoring lipoylation in mtFAS deficient yeast strains is not sufficient to support respiration and that long chain acyl-ACPs generated by mtFAS are required for mitochondrial function.
Collapse
Affiliation(s)
- M Tanvir Rahman
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - Joanna Panecka-Hofman
- Faculty of Physics, University of Warsaw, Warsaw, Poland
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
| | - Werner Schmitz
- Faculty of Biochemistry and Molecular Biology, University of Würzburg, Würzburg, Germany
| | | | - Rebecca C Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
- Zentrum für Molekulare Biologie (ZMBH), DKFZ-ZMBH Alliance and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
| | - Rik K Wierenga
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
| |
Collapse
|
9
|
Bridges HR, Blaza JN, Yin Z, Chung I, Pollak MN, Hirst J. Structural basis of mammalian respiratory complex I inhibition by medicinal biguanides. Science 2023; 379:351-357. [PMID: 36701435 PMCID: PMC7614227 DOI: 10.1126/science.ade3332] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The molecular mode of action of biguanides, including the drug metformin, which is widely used in the treatment of diabetes, is incompletely characterized. Here, we define the inhibitory drug-target interaction(s) of a model biguanide with mammalian respiratory complex I by combining cryo-electron microscopy and enzyme kinetics. We interpret these data to explain the selectivity of biguanide binding to different enzyme states. The primary inhibitory site is in an amphipathic region of the quinone-binding channel, and an additional binding site is in a pocket on the intermembrane-space side of the enzyme. An independent local chaotropic interaction, not previously described for any drug, displaces a portion of a key helix in the membrane domain. Our data provide a structural basis for biguanide action and enable the rational design of medicinal biguanides.
Collapse
Affiliation(s)
- Hannah R. Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK,Authors for correspondence: and
| | - James N. Blaza
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK,Structural Biology Laboratory and York Biomedical Research Institute, Department of Chemistry, The University of York, YO10 5DD, UK
| | - Zhan Yin
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Injae Chung
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Michael N. Pollak
- Lady Davis Institute of the Jewish General Hospital and Department of Oncology, McGill University, Montreal, QC H3T 1E2, Canada
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK,Authors for correspondence: and
| |
Collapse
|
10
|
Spiegel SJ, Sadun AA. Solutions to a Radical Problem: Overview of Current and Future Treatment Strategies in Leber's Hereditary Opic Neuropathy. Int J Mol Sci 2022; 23:13205. [PMID: 36361994 PMCID: PMC9656544 DOI: 10.3390/ijms232113205] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 09/23/2023] Open
Abstract
Leber's Hereditary Optic Neuropathy (LHON) is the most common primary mitochondrial DNA disorder. It is characterized by bilateral severe central subacute vision loss due to specific loss of Retinal Ganglion Cells and their axons. Historically, treatment options have been quite limited, but ongoing clinical trials show promise, with significant advances being made in the testing of free radical scavengers and gene therapy. In this review, we summarize management strategies and rational of treatment based on current insights from molecular research. This includes preventative recommendations for unaffected genetic carriers, current medical and supportive treatments for those affected, and emerging evidence for future potential therapeutics.
Collapse
Affiliation(s)
- Samuel J. Spiegel
- Gavin Herbert Eye Institute, University of California, Irvine, CA 92617, USA
| | - Alfredo A. Sadun
- Jules Stein and Doheny Eye Institute, University of California, Los Angeles, CA 90095, USA
| |
Collapse
|
11
|
Vikramdeo KS, Sudan SK, Singh AP, Singh S, Dasgupta S. Mitochondrial respiratory complexes: Significance in human mitochondrial disorders and cancers. J Cell Physiol 2022; 237:4049-4078. [PMID: 36074903 DOI: 10.1002/jcp.30869] [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: 11/17/2021] [Revised: 07/18/2022] [Accepted: 08/23/2022] [Indexed: 11/07/2022]
Abstract
Mitochondria are pivotal organelles that govern cellular energy production through the oxidative phosphorylation system utilizing five respiratory complexes. In addition, mitochondria also contribute to various critical signaling pathways including apoptosis, damage-associated molecular patterns, calcium homeostasis, lipid, and amino acid biosynthesis. Among these diverse functions, the energy generation program oversee by mitochondria represents an immaculate orchestration and functional coordination between the mitochondria and nuclear encoded molecules. Perturbation in this program through respiratory complexes' alteration results in the manifestation of various mitochondrial disorders and malignancy, which is alarmingly becoming evident in the recent literature. Considering the clinical relevance and importance of this emerging medical problem, this review sheds light on the timing and nature of molecular alterations in various respiratory complexes and their functional consequences observed in various mitochondrial disorders and human cancers. Finally, we discussed how this wealth of information could be exploited and tailored to develop respiratory complex targeted personalized therapeutics and biomarkers for better management of various incurable human mitochondrial disorders and cancers.
Collapse
Affiliation(s)
- Kunwar Somesh Vikramdeo
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Sarabjeet Kour Sudan
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Ajay P Singh
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Seema Singh
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Santanu Dasgupta
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| |
Collapse
|
12
|
Beck EA, Bassham S, Cresko WA. Extreme intraspecific divergence in mitochondrial haplotypes makes the threespine stickleback fish an emerging evolutionary mutant model for mito-nuclear interactions. Front Genet 2022; 13:925786. [PMID: 36159975 PMCID: PMC9499175 DOI: 10.3389/fgene.2022.925786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial DNA is primarily maternally inherited in most animals and evolves about 10 times faster than biparentally inherited nuclear DNA. Mitochondrial dysfunction (mt-dys) arises when interactions between the co-evolving mitochondrial and nuclear genomes are perturbed in essential processes like oxidative phosphorylation (OXPHOS). Over time mt-dys can lead to mitochondrial diseases (mt-diseases), which are surprisingly prevalent and include common diseases such as Alzheimer's, Parkinson's, and diabetes. Unfortunately, the strong impact that intraspecific mitochondrial and nuclear genetic variation has on mt-disease complicates its study and the development of effective treatments. Animal models have advanced our understanding of mt-disease but their relevance to human conditions is often limited by their relatively low nuclear genetic diversity. Many traditional laboratory models also typically have a single mitochondrial haplotype (mitotype), in stark contrast to over 5,000 mitotypes in humans worldwide. The threespine stickleback fish has an evolutionary history that has made it a favorable evolutionary mutant model (EMM) for studying mito-nuclear interactions and possibly mt-diseases. EMMs are species with naturally evolved states that mimic maladaptive human diseases. In threespine stickleback, a period of isolation followed by introgression of the mitochondrial genome from a sister species resulted in the maintenance of two distinct mitochondrial haplotypes which continue to segregate within many populations of wild stickleback. The existence of two mitogenomes segregating in numerous genetically diverse populations provides a unique system for exploring complex mito-nuclear dynamics. Here we provide the first complete coding region analysis of the two threespine stickleback mitotypes, whose mitogenomic divergence exceeds that of other mammalian models for mitochondrial disease and even that between ancient and modern humans. We find that divergence is not uniform across the mitogenome, but primarily impacts protein coding genes, and significantly impacts proteins in Complex I of OXPHOS. The full characterization of these highly divergent intraspecific mitotypes provides a foundation for the development of threespine stickleback as an EMM for mito-nuclear interactions.
Collapse
Affiliation(s)
- Emily A. Beck
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
- Presidential Initiative in Data Science, University of Oregon, Eugene, OR, United States
| | - Susan Bassham
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - William A. Cresko
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
- Presidential Initiative in Data Science, University of Oregon, Eugene, OR, United States
| |
Collapse
|
13
|
Li Y, Zhang Y, Jiang G, Wang Y, He C, Zhao X, Liu L, Li L. Case report: novel mutations of NDUFS6 and NHLRC2 genes potentially cause the quick postnatal death of a Chinese Hani minority neonate with mitochondrial complex I deficiency and FINCA syndrome. Medicine (Baltimore) 2022; 101:e29239. [PMID: 35801790 PMCID: PMC9259100 DOI: 10.1097/md.0000000000029239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
INTRODUCTION Mitochondrial complex I deficiency (MCID) and abbFINCA syndrome are lethal congenital diseases and cases in the neonatal period are rarely reported. Here, we identified a Chinese Hani minority neonate with rare MCID and FINCA syndrome. This study was to analyze the clinical manifestations and pathogenic gene variations, and to investigate causes of quick postnatal death of patient and possible molecular pathogenic mechanisms. PATIENT CONCERNS A 17-day-old patient had reduced muscle tension, diminished primitive reflexes, significantly abnormal blood gas analysis, and progressively increased blood lactate and blood glucose. Imaging studies revealed pneumonia, pulmonary hypertension, and brain abnormalities. DIAGNOSIS Whole-exome sequencing revealed that the NDUFS6 gene of the patient carried c. 344G > T (p.C115F) novel homozygous variation, and the NHLRC2 gene carried c. 1749C > G (p.F583L) and c. 2129C > T (p.T710M) novel compound heterozygous variation. INTERVENTIONS AND OUTCOMES The patient was given endotracheal intubation, respiratory support, high-frequency ventilation, antishock therapy, as well as iNO and Alprostadil to reduce pulmonary hypertension and maintain homeostatic equilibrium. However, the patient was critically ill and died in 27 days. CONCLUSION The patient has MCID due to a novel mutation in NDUFS6 and FINCA syndrome due to novel mutations in NHLRC2, which is the main reason for the rapid onset and quick death of the patient.
Collapse
Affiliation(s)
- Yangfang Li
- Department of Neonatology, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Yu Zhang
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children’s Major Disease Research, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Gengpan Jiang
- Department of Neonatology, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Yan Wang
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children’s Major Disease Research, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Canlin He
- Department of Neonatology, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Xiaofen Zhao
- Department of Neonatology, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Ling Liu
- Department of Neonatology, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
| | - Li Li
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children’s Major Disease Research, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, Kunming 650228, Yunnan, China
- *Correspondence: Li Li, Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children’s Major Disease Research, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, Kunming 650228, Yunnan, China (e-mail: )
| |
Collapse
|
14
|
Cryo-EM structures define ubiquinone-10 binding to mitochondrial complex I and conformational transitions accompanying Q-site occupancy. Nat Commun 2022; 13:2758. [PMID: 35589726 PMCID: PMC9120487 DOI: 10.1038/s41467-022-30506-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/04/2022] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial complex I is a central metabolic enzyme that uses the reducing potential of NADH to reduce ubiquinone-10 (Q10) and drive four protons across the inner mitochondrial membrane, powering oxidative phosphorylation. Although many complex I structures are now available, the mechanisms of Q10 reduction and energy transduction remain controversial. Here, we reconstitute mammalian complex I into phospholipid nanodiscs with exogenous Q10. Using cryo-EM, we reveal a Q10 molecule occupying the full length of the Q-binding site in the 'active' (ready-to-go) resting state together with a matching substrate-free structure, and apply molecular dynamics simulations to propose how the charge states of key residues influence the Q10 binding pose. By comparing ligand-bound and ligand-free forms of the 'deactive' resting state (that require reactivating to catalyse), we begin to define how substrate binding restructures the deactive Q-binding site, providing insights into its physiological and mechanistic relevance.
Collapse
|
15
|
TAT-Conjugated NDUFS8 Can Be Transduced into Mitochondria in a Membrane-Potential-Independent Manner and Rescue Complex I Deficiency. Int J Mol Sci 2021; 22:ijms22126524. [PMID: 34204592 PMCID: PMC8234171 DOI: 10.3390/ijms22126524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 12/21/2022] Open
Abstract
NADH dehydrogenase (ubiquinone) Fe-S protein 8 (NDUFS8) is a nuclear-encoded core subunit of human mitochondrial complex I. Defects in NDUFS8 are associated with Leigh syndrome and encephalomyopathy. Cell-penetrating peptide derived from the HIV-1 transactivator of transcription protein (TAT) has been successfully applied as a carrier to bring fusion proteins into cells without compromising the biological function of the cargoes. In this study, we developed a TAT-mediated protein transduction system to rescue complex I deficiency caused by NDUFS8 defects. Two fusion proteins (TAT-NDUFS8 and NDUFS8-TAT) were exogenously expressed and purified from Escherichia coli for transduction of human cells. In addition, similar constructs were generated and used in transfection studies for comparison. The results showed that both exogenous TAT-NDUFS8 and NDUFS8-TAT were delivered into mitochondria and correctly processed. Interestingly, the mitochondrial import of TAT-containing NDUFS8 was independent of mitochondrial membrane potential. Treatment with TAT-NDUFS8 not only significantly improved the assembly of complex I in an NDUFS8-deficient cell line, but also partially rescued complex I functions both in the in-gel activity assay and the oxygen consumption assay. Our current findings suggest the considerable potential of applying the TAT-mediated protein transduction system for treatment of complex I deficiency.
Collapse
|
16
|
Biochemical consequences of two clinically relevant ND-gene mutations in Escherichia coli respiratory complex I. Sci Rep 2021; 11:12641. [PMID: 34135385 PMCID: PMC8209014 DOI: 10.1038/s41598-021-91631-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/28/2021] [Indexed: 11/28/2022] Open
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) plays a major role in energy metabolism by coupling electron transfer from NADH to quinone with proton translocation across the membrane. Complex I deficiencies were found to be the most common source of human mitochondrial dysfunction that manifest in a wide variety of neurodegenerative diseases. Seven subunits of human complex I are encoded by mitochondrial DNA (mtDNA) that carry an unexpectedly large number of mutations discovered in mitochondria from patients’ tissues. However, whether or how these genetic aberrations affect complex I at a molecular level is unknown. Here, we used Escherichia coli as a model system to biochemically characterize two mutations that were found in mtDNA of patients. The V253AMT-ND5 mutation completely disturbed the assembly of complex I, while the mutation D199GMT-ND1 led to the assembly of a stable complex capable to catalyze redox-driven proton translocation. However, the latter mutation perturbs quinone reduction leading to a diminished activity. D199MT-ND1 is part of a cluster of charged amino acid residues that are suggested to be important for efficient coupling of quinone reduction and proton translocation. A mechanism considering the role of D199MT-ND1 for energy conservation in complex I is discussed.
Collapse
|
17
|
Accessory Subunits of the Matrix Arm of Mitochondrial Complex I with a Focus on Subunit NDUFS4 and Its Role in Complex I Function and Assembly. Life (Basel) 2021; 11:life11050455. [PMID: 34069703 PMCID: PMC8161149 DOI: 10.3390/life11050455] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 12/19/2022] Open
Abstract
NADH:ubiquinone-oxidoreductase (complex I) is the largest membrane protein complex of the respiratory chain. Complex I couples electron transfer to vectorial proton translocation across the inner mitochondrial membrane. The L shaped structure of complex I is divided into a membrane arm and a matrix arm. Fourteen central subunits are conserved throughout species, while some 30 accessory subunits are typically found in eukaryotes. Complex I dysfunction is associated with mutations in the nuclear and mitochondrial genome, resulting in a broad spectrum of neuromuscular and neurodegenerative diseases. Accessory subunit NDUFS4 in the matrix arm is a hot spot for mutations causing Leigh or Leigh-like syndrome. In this review, we focus on accessory subunits of the matrix arm and discuss recent reports on the function of accessory subunit NDUFS4 and its interplay with NDUFS6, NDUFA12, and assembly factor NDUFAF2 in complex I assembly.
Collapse
|
18
|
Bandara AB, Drake JC, James CC, Smyth JW, Brown DA. Complex I protein NDUFS2 is vital for growth, ROS generation, membrane integrity, apoptosis, and mitochondrial energetics. Mitochondrion 2021; 58:160-168. [PMID: 33744462 DOI: 10.1016/j.mito.2021.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022]
Abstract
Complex I is the largest and most intricate of the protein complexes of mitochondrial electron transport chain (ETC). This L-shaped enzyme consists of a peripheral hydrophilic matrix domain and a membrane-bound orthogonal hydrophobic domain. The interfacial region between these two arms is known to be critical for binding of ubiquinone moieties and has also been shown to be the binding site of Complex I inhibitors. Knowledge on specific roles of the ETC interfacial region proteins is scarce due to lack of knockout cell lines and animal models. Here we mutated nuclear encoded NADH dehydrogenase [ubiquinone] iron-sulfur protein 2 (NDUFS2), one of three protein subunits of the interfacial region, in a human embryonic kidney cell line 293 using a CRISPR/Cas9 procedure. Disruption of NDUFS2 significantly decreased cell growth in medium, Complex I specific respiration, glycolytic capacity, ATP pool and cell-membrane integrity, but significantly increased Complex II respiration, ROS generation, apoptosis, and necrosis. Treatment with idebenone, a clinical benzoquinone currently being investigated in other indications, partially restored growth, ATP pool, and oxygen consumption of the mutant. Overall, our results suggest that NDUFS2 is vital for growth and metabolism of mammalian cells, and respiratory defects of NDUFS2 dysfunction can be partially corrected with treatment of an established mitochondrial therapeutic candidate. This is the first report to use CRISPR/Cas9 approach to construct a knockout NDUFS2 cell line and use the constructed mutant to evaluate the efficacy of a known mitochondrial therapeutic to enhance bioenergetic capacity.
Collapse
Affiliation(s)
- Aloka B Bandara
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA 24061, United States; Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, United States.
| | - Joshua C Drake
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA 24061, United States
| | - Carissa C James
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, United States; Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, United States
| | - James W Smyth
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, United States; Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, United States; Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, United States
| | - David A Brown
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA 24061, United States; Mitochondrial Solutions, LLC, 800 Draper Road, Blacksburg VA 24060, United States
| |
Collapse
|
19
|
Pamplona R, Jové M, Mota-Martorell N, Barja G. Is the NDUFV2 subunit of the hydrophilic complex I domain a key determinant of animal longevity? FEBS J 2021; 288:6652-6673. [PMID: 33455045 DOI: 10.1111/febs.15714] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/02/2020] [Accepted: 01/14/2021] [Indexed: 12/18/2022]
Abstract
Complex I, a component of the electron transport chain, plays a central functional role in cell bioenergetics and the biology of free radicals. The structural and functional N module of complex I is one of the main sites of the generation of free radicals. The NDUFV2 subunit/N1a cluster is a component of this module. Furthermore, the rate of free radical production is linked to animal longevity. In this review, we explore the hypothesis that NDUFV2 is the only conserved core subunit designed with a regulatory function to ensure correct electron transfer and free radical production, that low gene expression and protein abundance of the NDUFV2 subunit is an evolutionary adaptation needed to achieve a longevity phenotype, and that these features are determinants of the lower free radical generation at the mitochondrial level and a slower rate of aging of long-lived animals.
Collapse
Affiliation(s)
- Reinald Pamplona
- Department of Experimental Medicine, University of Lleida-Lleida Biomedical Research Institute (UdL-IRBLleida), Lleida, Spain
| | - Mariona Jové
- Department of Experimental Medicine, University of Lleida-Lleida Biomedical Research Institute (UdL-IRBLleida), Lleida, Spain
| | - Natalia Mota-Martorell
- Department of Experimental Medicine, University of Lleida-Lleida Biomedical Research Institute (UdL-IRBLleida), Lleida, Spain
| | - Gustavo Barja
- Department of Genetics, Physiology and Microbiology, Complutense University of Madrid, Madrid, Spain
| |
Collapse
|
20
|
Cytochrome c oxidase deficiency. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148335. [PMID: 33171185 DOI: 10.1016/j.bbabio.2020.148335] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 12/23/2022]
Abstract
Cytochrome c oxidase (COX) deficiency is characterized by a high degree of genetic and phenotypic heterogeneity, partly reflecting the extreme structural complexity, multiple post-translational modification, variable, tissue-specific composition, and the high number of and intricate connections among the assembly factors of this enzyme. In fact, decreased COX specific activity can manifest with different degrees of severity, affect the whole organism or specific tissues, and develop a wide spectrum of disease natural history, including disease onsets ranging from birth to late adulthood. More than 30 genes have been linked to COX deficiency, but the list is still incomplete and in fact constantly updated. We here discuss the current knowledge about COX in health and disease, focusing on genetic aetiology and link to clinical manifestations. In addition, information concerning either fundamental biological features of the enzymes or biochemical signatures of its defects have been provided by experimental in vivo models, including yeast, fly, mouse and fish, which expanded our knowledge on the functional features and the phenotypical consequences of different forms of COX deficiency.
Collapse
|
21
|
Čunátová K, Reguera DP, Houštěk J, Mráček T, Pecina P. Role of cytochrome c oxidase nuclear-encoded subunits in health and disease. Physiol Res 2020; 69:947-965. [PMID: 33129245 DOI: 10.33549/physiolres.934446] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cytochrome c oxidase (COX), the terminal enzyme of mitochondrial electron transport chain, couples electron transport to oxygen with generation of proton gradient indispensable for the production of vast majority of ATP molecules in mammalian cells. The review summarizes current knowledge of COX structure and function of nuclear-encoded COX subunits, which may modulate enzyme activity according to various conditions. Moreover, some nuclear-encoded subunits posess tissue-specific and development-specific isoforms, possibly enabling fine-tuning of COX function in individual tissues. The importance of nuclear-encoded subunits is emphasized by recently discovered pathogenic mutations in patients with severe mitopathies. In addition, proteins substoichiometrically associated with COX were found to contribute to COX activity regulation and stabilization of the respiratory supercomplexes. Based on the summarized data, a model of three levels of quaternary COX structure is postulated. Individual structural levels correspond to subunits of the i) catalytic center, ii) nuclear-encoded stoichiometric subunits and iii) associated proteins, which may constitute several forms of COX with varying composition and differentially regulated function.
Collapse
Affiliation(s)
- K Čunátová
- Department of Bioenergetics, Institute of Physiology CAS, Prague, Czech Republic. ,
| | | | | | | | | |
Collapse
|
22
|
Kadenbach B. Regulation of cytochrome c oxidase contributes to health and optimal life. World J Biol Chem 2020; 11:52-61. [PMID: 33024517 PMCID: PMC7520645 DOI: 10.4331/wjbc.v11.i2.52] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/01/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
The generation of cellular energy in the form of ATP occurs mainly in mitochondria by oxidative phosphorylation. Cytochrome c oxidase (CytOx), the oxygen accepting and rate-limiting step of the respiratory chain, regulates the supply of variable ATP demands in cells by “allosteric ATP-inhibition of CytOx.” This mechanism is based on inhibition of oxygen uptake of CytOx at high ATP/ADP ratios and low ferrocytochrome c concentrations in the mitochondrial matrix via cooperative interaction of the two substrate binding sites in dimeric CytOx. The mechanism keeps mitochondrial membrane potential ΔΨm and reactive oxygen species (ROS) formation at low healthy values. Stress signals increase cytosolic calcium leading to Ca2+-dependent dephosphorylation of CytOx subunit I at the cytosolic side accompanied by switching off the allosteric ATP-inhibition and monomerization of CytOx. This is followed by increase of ΔΨm and formation of ROS. A hypothesis is presented suggesting a dynamic change of binding of NDUFA4, originally identified as a subunit of complex I, between monomeric CytOx (active state with high ΔΨm, high ROS and low efficiency) and complex I (resting state with low ΔΨm, low ROS and high efficiency).
Collapse
Affiliation(s)
- Bernhard Kadenbach
- Department of Chemistry/Biochemistry, Fachbereich Chemie, Philipps-Universität Marburg, Marburg D-35043, Hessen, Germany
| |
Collapse
|
23
|
Bergman O, Karry R, Milhem J, Ben-Shachar D. NDUFV2 pseudogene (NDUFV2P1) contributes to mitochondrial complex I deficits in schizophrenia. Mol Psychiatry 2020; 25:805-820. [PMID: 30531937 DOI: 10.1038/s41380-018-0309-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/06/2018] [Accepted: 11/14/2018] [Indexed: 12/18/2022]
Abstract
Mitochondria together with other cellular components maintain a constant crosstalk, modulating transcriptional and posttranslational processes. We and others demonstrated mitochondrial multifaceted dysfunction in schizophrenia, with aberrant complex I (CoI) as a major cause. Here we show deficits in CoI activity and homeostasis in schizophrenia-derived cell lines. Focusing on a core CoI subunit, NDUFV2, one of the most severely affected subunits in schizophrenia, we observed reduced protein level and functioning, with no change in mRNA transcripts. We further show that NDUFV2 pseudogene (NDUFV2P1) expression is increased in schizophrenia-derived cells and in postmortem brain specimens. In schizophrenia and controls pooled samples, NDUFV2P1 level demonstrated a significant inverse correlation with NDUFV2 pre- and matured protein level and with CoI-driven cellular respiration. Our data suggest a role for a pseudogene in its parent-gene regulation and possibly in CoI dysfunction in schizophrenia. The abnormal expression of the pseudogene may be one element of a vicious circle in which CoI deficits lead to mitochondrial dysfunction potentially affecting genome-wide regulation of gene expression, including the expression of pseudogenes.
Collapse
Affiliation(s)
- Oded Bergman
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rachel Karry
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel
| | - Jumana Milhem
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel
| | - Dorit Ben-Shachar
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel.
| |
Collapse
|
24
|
Abstract
Biology students today are taught that mitochondria are 'the powerhouse of the cell'. This gross over-simplification of their cellular role has arguably led to a paucity of knowledge concerning the many other tasks carried out by this multifunctional organelle. Mitochondrial fatty acid synthesis (mtFAS) is one such under-appreciated pathway that is crucial for mitochondrial function, although even mitochondrial experts are often surprised to learn of its existence. For many years, the only function of mtFAS was thought to be the production of lipoic acid, an important co-factor for several mitochondrial enzymes. However, recent advances have revealed a far wider role for mtFAS in mitochondrial physiology. The discovery of human patients with mutations in mtFAS enzymes has brought renewed interest in understanding the full significance of this novel mode of mitochondrial metabolic regulation. We now appreciate that mtFAS is a nutrient-sensitive pathway that provides an elegant mechanism whereby acetyl-CoA regulates its own consumption via coordination of lipoic acid synthesis and tricarboxylic acid (TCA) cycle activity, iron-sulfur (FeS) cluster biogenesis, assembly of oxidative phosphorylation complexes, and mitochondrial translation. In this minireview, we describe and build upon the important discoveries that led to our current understanding of this elegant mechanism of coordination of nutrient status and metabolism.
Collapse
|
25
|
Ni Y, Hagras MA, Konstantopoulou V, Mayr JA, Stuchebrukhov AA, Meierhofer D. Mutations in NDUFS1 Cause Metabolic Reprogramming and Disruption of the Electron Transfer. Cells 2019; 8:cells8101149. [PMID: 31557978 PMCID: PMC6829531 DOI: 10.3390/cells8101149] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 01/07/2023] Open
Abstract
Complex I (CI) is the first enzyme of the mitochondrial respiratory chain and couples the electron transfer with proton pumping. Mutations in genes encoding CI subunits can frequently cause inborn metabolic errors. We applied proteome and metabolome profiling of patient-derived cells harboring pathogenic mutations in two distinct CI genes to elucidate underlying pathomechanisms on the molecular level. Our results indicated that the electron transfer within CI was interrupted in both patients by different mechanisms. We showed that the biallelic mutations in NDUFS1 led to a decreased stability of the entire N-module of CI and disrupted the electron transfer between two iron–sulfur clusters. Strikingly interesting and in contrast to the proteome, metabolome profiling illustrated that the pattern of dysregulated metabolites was almost identical in both patients, such as the inhibitory feedback on the TCA cycle and altered glutathione levels, indicative for reactive oxygen species (ROS) stress. Our findings deciphered pathological mechanisms of CI deficiency to better understand inborn metabolic errors.
Collapse
Affiliation(s)
- Yang Ni
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
- Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
- Present address: Laboratory of Angiogenesis and Vascular Metabolism, VIB-KU Leuven Center for Cancer Biology, 3000 Leuven, Belgium
| | - Muhammad A. Hagras
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA; (M.A.H.); (A.A.S.)
- Present address: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Vassiliki Konstantopoulou
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria;
| | - Johannes A. Mayr
- Department of Pediatrics, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria;
| | - Alexei A. Stuchebrukhov
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA; (M.A.H.); (A.A.S.)
| | - David Meierhofer
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
- Correspondence: ; Tel.: +49-30-8413-1567
| |
Collapse
|
26
|
Yang D, Wan Y. Molecular determinants for the polarization of macrophage and osteoclast. Semin Immunopathol 2019; 41:551-563. [PMID: 31506868 PMCID: PMC6815265 DOI: 10.1007/s00281-019-00754-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/29/2019] [Indexed: 12/31/2022]
Abstract
Emerging evidence suggest that macrophage and osteoclast are two competing differentiation outcomes from myeloid progenitors. In this review, we summarize recent advances in the understanding of the molecular mechanisms controlling the polarization of macrophage and osteoclast. These include nuclear receptors/transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ) and estrogen-related receptor α (ERRα), their transcription cofactor PPARγ coactivator 1-β (PGC-1β), metabolic factors such as mitochondrial complex I (CI) component NADH:ubiquinone oxidoreductase iron-sulfur protein 4 (Ndufs4), as well as transmembrane receptors such as very-low-density-lipoprotein receptor (VLDLR). These molecular rheostats promote osteoclast differentiation but suppress proinflammatory macrophage activation and inflammation, by acting lineage-intrinsically, systemically or cross generation. These findings provide new insights to the understanding of the interactions between innate immunity and bone remodeling, advancing the field of osteoimmunology.
Collapse
Affiliation(s)
- Dengbao Yang
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Yihong Wan
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| |
Collapse
|
27
|
Masud AJ, Kastaniotis AJ, Rahman MT, Autio KJ, Hiltunen JK. Mitochondrial acyl carrier protein (ACP) at the interface of metabolic state sensing and mitochondrial function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118540. [PMID: 31473256 DOI: 10.1016/j.bbamcr.2019.118540] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 12/20/2022]
Abstract
Acyl carrier protein (ACP) is a principal partner in the cytosolic and mitochondrial fatty acid synthesis (FAS) pathways. The active form holo-ACP serves as FAS platform, using its 4'-phosphopantetheine group to present covalently attached FAS intermediates to the enzymes responsible for the acyl chain elongation process. Mitochondrial unacylated holo-ACP is a component of mammalian mitoribosomes, and acylated ACP species participate as interaction partners in several ACP-LYRM (leucine-tyrosine-arginine motif)-protein heterodimers that act either as assembly factors or subunits of the electron transport chain and Fe-S cluster assembly complexes. Moreover, octanoyl-ACP provides the C8 backbone for endogenous lipoic acid synthesis. Accumulating evidence suggests that mtFAS-generated acyl-ACPs act as signaling molecules in an intramitochondrial metabolic state sensing circuit, coordinating mitochondrial acetyl-CoA levels with mitochondrial respiration, Fe-S cluster biogenesis and protein lipoylation.
Collapse
Affiliation(s)
- Ali J Masud
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - M Tanvir Rahman
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
| |
Collapse
|
28
|
Barshad G, Zlotnikov-Poznianski N, Gal L, Schuldiner M, Mishmar D. Disease-causing mutations in subunits of OXPHOS complex I affect certain physical interactions. Sci Rep 2019; 9:9987. [PMID: 31292494 PMCID: PMC6620328 DOI: 10.1038/s41598-019-46446-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 06/28/2019] [Indexed: 11/09/2022] Open
Abstract
Mitochondrial complex I (CI) is the largest multi-subunit oxidative phosphorylation (OXPHOS) protein complex. Recent availability of a high-resolution human CI structure, and from two non-human mammals, enabled predicting the impact of mutations on interactions involving each of the 44 CI subunits. However, experimentally assessing the impact of the predicted interactions requires an easy and high-throughput method. Here, we created such a platform by cloning all 37 nuclear DNA (nDNA) and 7 mitochondrial DNA (mtDNA)-encoded human CI subunits into yeast expression vectors to serve as both 'prey' and 'bait' in the split murine dihydrofolate reductase (mDHFR) protein complementation assay (PCA). We first demonstrated the capacity of this approach and then used it to examine reported pathological OXPHOS CI mutations that occur at subunit interaction interfaces. Our results indicate that a pathological frame-shift mutation in the MT-ND2 gene, causing the replacement of 126 C-terminal residues by a stretch of only 30 amino acids, resulted in loss of specificity in ND2-based interactions involving these residues. Hence, the split mDHFR PCA is a powerful assay for assessing the impact of disease-causing mutations on pairwise protein-protein interactions in the context of a large protein complex, thus offering a possible mechanistic explanation for the underlying pathogenicity.
Collapse
Affiliation(s)
- Gilad Barshad
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - Lihi Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Dan Mishmar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| |
Collapse
|
29
|
Ligas J, Pineau E, Bock R, Huynen MA, Meyer EH. The assembly pathway of complex I in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:447-459. [PMID: 30347487 DOI: 10.1111/tpj.14133] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/09/2018] [Accepted: 10/16/2018] [Indexed: 05/23/2023]
Abstract
All present-day mitochondria originate from a single endosymbiotic event that gave rise to the last eukaryotic common ancestor more than a billion years ago. However, to date, many aspects of mitochondrial evolution have remained unresolved. Comparative genomics and proteomics have revealed a complex evolutionary origin for many mitochondrial components. To understand the evolution of the respiratory chain, we have examined both the components and the mechanisms of the assembly pathway of complex I. Complex I represents the first enzyme in the respiratory chain, and complex I deficiencies have dramatic consequences in both animals and plants. The complex is located in the mitochondrial inner membrane and possesses two arms: one embedded in the inner membrane and one protruding in the matrix. Here, we describe the assembly pathway of complex I in the model plant Arabidopsis thaliana. Using a proteomics approach called complexome profiling, we have resolved the different steps in the assembly process in plants. We propose a model for the stepwise assembly of complex I, including every subunit. We then compare this pathway with the corresponding pathway in humans and find that complex I assembly in plants follows a different, and likely ancestral, pathway compared with the one in humans. We show that the main evolutionary changes in complex I structure and assembly in humans occurred at the level of the membrane arm, whereas the matrix arm remained rather conserved.
Collapse
Affiliation(s)
- Joanna Ligas
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Emmanuelle Pineau
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 Rue du Général Zimmer, 67084, Strasbourg, France
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics, Radboud Centre for Mitochondrial Medicine, Radboud University, Nijmegen, The Netherlands
| | - Etienne H Meyer
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 Rue du Général Zimmer, 67084, Strasbourg, France
| |
Collapse
|
30
|
Strangers in strange lands: mitochondrial proteins found at extra-mitochondrial locations. Biochem J 2019; 476:25-37. [DOI: 10.1042/bcj20180473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 12/18/2022]
Abstract
Abstract
The mitochondrial proteome is estimated to contain ∼1100 proteins, the vast majority of which are nuclear-encoded, with only 13 proteins encoded by the mitochondrial genome. The import of these nuclear-encoded proteins into mitochondria was widely believed to be unidirectional, but recent discoveries have revealed that many these ‘mitochondrial’ proteins are exported, and have extra-mitochondrial activities divergent from their mitochondrial function. Surprisingly, three of the exported proteins discovered thus far are mitochondrially encoded and have significantly different extra-mitochondrial roles than those performed within the mitochondrion. In this review, we will detail the wide variety of proteins once thought to only reside within mitochondria, but now known to ‘emigrate’ from mitochondria in order to attain ‘dual citizenship’, present both within mitochondria and elsewhere.
Collapse
|
31
|
Abstract
Leigh syndrome (LS) is a common neurodegenerative disease affecting neonates with devastating sequences. One of the characteristic features for LS is the phenotypic polymorphism, which-in part-can be dedicated to variety of genetic causes. A strong correlation with mitochondrial dysfunction has been assumed as the main cause of LS. This was based on the fact that most genetic causes are related to mitochondrial complex I genome. The first animal LS model was designed based on NDUFS4 knockdown. Interestingly, however, this one or others could not recapitulate the whole spectrum of manifestations encountered in different cases of LS. We show in this chapter a new animal model for LS based on silencing of one gene that is reported previously in clinical cases, FOXRED1. The new model carries some differences from previous models in the fact that more histopathological degeneration in dopaminergic system is seen and more behavioral changes can be recognized. FOXRED1 is an interesting gene that is related to complex I assembly, hence, plays important role in different neurodegenerative disorders leading to different clinical manifestations.
Collapse
Affiliation(s)
- Sara El-Desouky
- Medical Experimental Research Center (MERC), Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Yasmeen M Taalab
- Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
- German Institute of Disaster Medicine and Emergency Medicine, Tubingen, Germany
| | - Mohamed El-Gamal
- Medical Experimental Research Center (MERC), Faculty of Medicine, Mansoura University, Mansoura, Egypt
- Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Wael Mohamed
- Clinical Pharmacology Department, Faculty of Medicine, Menoufia University, Al Minufya, Egypt
- Department of Basic Medical Science, Kulliyyah of Medicine, International Islamic University, Kuantan, Pahang, Malaysia
| | - Mohamed Salama
- Medical Experimental Research Center (MERC), Faculty of Medicine, Mansoura University, Mansoura, Egypt.
- Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
- Atlantic Fellow for Global Brain Health Institute (GBHI), Trinity College Dublin (TCD), Dublin, Ireland.
| |
Collapse
|
32
|
|
33
|
Chorev DS, Baker LA, Wu D, Beilsten-Edmands V, Rouse SL, Zeev-Ben-Mordehai T, Jiko C, Samsudin F, Gerle C, Khalid S, Stewart AG, Matthews SJ, Grünewald K, Robinson CV. Protein assemblies ejected directly from native membranes yield complexes for mass spectrometry. Science 2018; 362:829-834. [PMID: 30442809 PMCID: PMC6522346 DOI: 10.1126/science.aau0976] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
Abstract
Membrane proteins reside in lipid bilayers and are typically extracted from this environment for study, which often compromises their integrity. In this work, we ejected intact assemblies from membranes, without chemical disruption, and used mass spectrometry to define their composition. From Escherichia coli outer membranes, we identified a chaperone-porin association and lipid interactions in the β-barrel assembly machinery. We observed efflux pumps bridging inner and outer membranes, and from inner membranes we identified a pentameric pore of TonB, as well as the protein-conducting channel SecYEG in association with F1FO adenosine triphosphate (ATP) synthase. Intact mitochondrial membranes from Bos taurus yielded respiratory complexes and fatty acid-bound dimers of the ADP (adenosine diphosphate)/ATP translocase (ANT-1). These results highlight the importance of native membrane environments for retaining small-molecule binding, subunit interactions, and associated chaperones of the membrane proteome.
Collapse
Affiliation(s)
- Dror S Chorev
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Lindsay A Baker
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Di Wu
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Victoria Beilsten-Edmands
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Sarah L Rouse
- Department of Life Sciences, Imperial College, London, South Kensington Campus, London SW7 2AZ, UK
| | | | - Chimari Jiko
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Japan
| | - Firdaus Samsudin
- School of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Christoph Gerle
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
- Core Research for Evolutional Science and Technology, Japan and Science and Technology Agency, Kawaguchi, Japan
| | - Syma Khalid
- School of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Alastair G Stewart
- Molecular, Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - Stephen J Matthews
- Department of Life Sciences, Imperial College, London, South Kensington Campus, London SW7 2AZ, UK
| | - Kay Grünewald
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Centre of Structural Systems Biology (CSSB), Notkestr. 85, D-22607, Heinrich-Pette Institute/University of Hamburg, Hamburg, Germany
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK.
| |
Collapse
|
34
|
Impaired Mitochondrial Fatty Acid Synthesis Leads to Neurodegeneration in Mice. J Neurosci 2018; 38:9781-9800. [PMID: 30266742 DOI: 10.1523/jneurosci.3514-17.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 08/31/2018] [Accepted: 09/19/2018] [Indexed: 01/07/2023] Open
Abstract
There has been a growing interest toward mitochondrial fatty acid synthesis (mtFAS) since the recent discovery of a neurodegenerative human disorder termed MEPAN (mitochondrial enoyl reductase protein associated neurodegeneration), which is caused by mutations in the mitochondrial enoyl-CoA/ACP (acyl carrier protein) reductase (MECR) carrying out the last step of mtFAS. We show here that MECR protein is highly expressed in mouse Purkinje cells (PCs). To elucidate mtFAS function in neural tissue, here, we generated a mouse line with a PC-specific knock-out (KO) of Mecr, leading to inactivation of mtFAS confined to this cell type. Both sexes were studied. The mitochondria in KO PCs displayed abnormal morphology, loss of protein lipoylation, and reduced respiratory chain enzymatic activities by the time these mice were 6 months of age, followed by nearly complete loss of PCs by 9 months of age. These animals exhibited balancing difficulties ∼7 months of age and ataxic symptoms were evident from 8-9 months of age on. Our data show that impairment of mtFAS results in functional and ultrastructural changes in mitochondria followed by death of PCs, mimicking aspects of the clinical phenotype. This KO mouse represents a new model for impaired mitochondrial lipid metabolism and cerebellar ataxia with a distinct and well trackable cellular phenotype. This mouse model will allow the future investigation of the feasibility of metabolite supplementation approaches toward the prevention of neurodegeneration due to dysfunctional mtFAS.SIGNIFICANCE STATEMENT We have recently reported a novel neurodegenerative disorder in humans termed MEPAN (mitochondrial enoyl reductase protein associated neurodegeneration) (Heimer et al., 2016). The cause of neuron degeneration in MEPAN patients is the dysfunction of the highly conserved mitochondrial fatty acid synthesis (mtFAS) pathway due to mutations in MECR, encoding mitochondrial 2-enoyl-CoA/ACP reductase. The report presented here describes the analysis of the first mouse model suffering from mtFAS-defect-induced neurodegenerative changes due to specific disruption of the Mecr gene in Purkinje cells. Our work sheds a light on the mechanisms of neurodegeneration caused by mtFAS deficiency and provides a test bed for future treatment approaches.
Collapse
|
35
|
Mitochondrial complex I in the post-ischemic heart: reperfusion-mediated oxidative injury and protein cysteine sulfonation. J Mol Cell Cardiol 2018; 121:190-204. [PMID: 30031815 DOI: 10.1016/j.yjmcc.2018.07.244] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 12/20/2022]
Abstract
A serious consequence of ischemia-reperfusion injury (I/R) is oxidative damage leading to mitochondrial dysfunction. Such I/R-induced mitochondrial dysfunction is observed as impaired state 3 respiration and overproduction of O2-. The cascading ROS can propagate cysteine oxidation on mitochondrial complex I and add insult to injury. Herein we employed LC-MS/MS to identify protein sulfonation of complex I in mitochondria from the infarct region of rat hearts subjected to 30-min of coronary ligation and 24-h of reperfusion in vivo as well as the mitochondria of sham controls. Mitochondrial preparations from the I/R regions had enhanced sulfonation levels on the cysteine ligands of iron‑sulfur clusters, including N3 (C425), N1b (C92), N4 (C226), N2 (C158/C188), and N1a (C134/C139). The 4Fe-4S centers of N3, N1b, N4, and N2 are key redox-active components of complex I, thus sulfonation of metal-binding sites impaired the main electron transfer pathway. The binuclear N1a has a very low redox potential and an antioxidative function. Increased C134/C139 sulfonation by I/R impaired the N1a cluster, potentially contributing to overall O2- generation by the FMN moiety of complex I. MS analysis also revealed I/R-mediated increased sulfonation at the core subunits of 51 kDa (C125, C187, C206, C238, C255, C286), 75 kDa (C367, C554, C564, C727), 49 kDa (C146, C326, C347), and PSST (C188). These results were consistent with the consensus indicating that 51 kDa and 75 kDa are two of major subunits hosting regulatory thiols, and their enhanced sulfonation by I/R predisposed the myocardium to further oxidant stress with impaired ubiquinone reduction. MS analysis further showed I/R-mediated enhanced sulfonation at the supernumerary subunits of 42 kDa (C67, C112, C183, C253), 15 kDa (C43), and 13 kDa (C79). The 42 kDa protein is metazoan-specific, which was reported to stabilize mammalian complex I. C43 of the 15 kDa subunit forms an intramolecular disulfide bond with C56, which was reported to stabilize complex I structure. C79 of the 13 kDa subunit is involved in Zn2+-binding, which was reported functionally important for complex I assembly. C79 sulfonation by I/R was found to impair Zn2+-binding. No significant enhancement of protein sulfonation was observed in mitochondrial complex I from the rat heart subjected to 30-min ischemia alone in vivo despite a decreased state 3 respiration, suggesting that the physiologic conditions of hyperoxygenation during reperfusion mediated an increase in complex I sulfonation and oxidative injury. In conclusion, sulfonation of specific cysteines of complex I mediates I/R-induced mitochondrial dysfunction via impaired ETC activity, increasing •O2- production, and mediating redox dysfunction of complex I.
Collapse
|
36
|
Plant mitochondrial protein import: the ins and outs. Biochem J 2018; 475:2191-2208. [PMID: 30018142 DOI: 10.1042/bcj20170521] [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: 05/24/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 01/29/2023]
Abstract
The majority of the mitochondrial proteome, required to fulfil its diverse range of functions, is cytosolically synthesised and translocated via specialised machinery. The dedicated translocases, receptors, and associated proteins have been characterised in great detail in yeast over the last several decades, yet many of the mechanisms that regulate these processes in higher eukaryotes are still unknown. In this review, we highlight the current knowledge of mitochondrial protein import in plants. Despite the fact that the mechanisms of mitochondrial protein import have remained conserved across species, many unique features have arisen in plants to encompass the developmental, tissue-specific, and stress-responsive regulation in planta. An understanding of unique features and mechanisms in plants provides us with a unique insight into the regulation of mitochondrial biogenesis in higher eukaryotes.
Collapse
|
37
|
Abstract
Codon usage depends on mutation bias, tRNA-mediated selection, and the need for high efficiency and accuracy in translation. One codon in a synonymous codon family is often strongly over-used, especially in highly expressed genes, which often leads to a high dN/dS ratio because dS is very small. Many different codon usage indices have been proposed to measure codon usage and codon adaptation. Sense codon could be misread by release factors and stop codons misread by tRNAs, which also contribute to codon usage in rare cases. This chapter outlines the conceptual framework on codon evolution, illustrates codon-specific and gene-specific codon usage indices, and presents their applications. A new index for codon adaptation that accounts for background mutation bias (Index of Translation Elongation) is presented and contrasted with codon adaptation index (CAI) which does not consider background mutation bias. They are used to re-analyze data from a recent paper claiming that translation elongation efficiency matters little in protein production. The reanalysis disproves the claim.
Collapse
|
38
|
Miranda-Astudillo HV, Yadav KNS, Colina-Tenorio L, Bouillenne F, Degand H, Morsomme P, Boekema EJ, Cardol P. The atypical subunit composition of respiratory complexes I and IV is associated with original extra structural domains in Euglena gracilis. Sci Rep 2018; 8:9698. [PMID: 29946152 PMCID: PMC6018760 DOI: 10.1038/s41598-018-28039-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/14/2018] [Indexed: 11/10/2022] Open
Abstract
In mitochondrial oxidative phosphorylation, electron transfer from NADH or succinate to oxygen by a series of large protein complexes in the inner mitochondrial membrane (complexes I-IV) is coupled to the generation of an electrochemical proton gradient, the energy of which is utilized by complex V to generate ATP. In Euglena gracilis, a non-parasitic secondary green alga related to trypanosomes, these respiratory complexes totalize more than 40 Euglenozoa-specific subunits along with about 50 classical subunits described in other eukaryotes. In the present study the Euglena proton-pumping complexes I, III, and IV were purified from isolated mitochondria by a two-steps liquid chromatography approach. Their atypical subunit composition was further resolved and confirmed using a three-steps PAGE analysis coupled to mass spectrometry identification of peptides. The purified complexes were also observed by electron microscopy followed by single-particle analysis. Even if the overall structures of the three oxidases are similar to the structure of canonical enzymes (e.g. from mammals), additional atypical domains were observed in complexes I and IV: an extra domain located at the tip of the peripheral arm of complex I and a "helmet-like" domain on the top of the cytochrome c binding region in complex IV.
Collapse
Affiliation(s)
- H V Miranda-Astudillo
- Laboratoire de Génétique et Physiologie des microalgues, InBioS/Phytosystems, Institut de Botanique, Université de Liège, Liege, Belgium
| | - K N S Yadav
- Department of Electron Microscopy, Groningen Biological Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - L Colina-Tenorio
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico, Mexico
| | - F Bouillenne
- InBioS/Center for Protein Engineering, Université de Liège, Liege, Belgium
| | - H Degand
- Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - P Morsomme
- Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - E J Boekema
- Department of Electron Microscopy, Groningen Biological Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - P Cardol
- Laboratoire de Génétique et Physiologie des microalgues, InBioS/Phytosystems, Institut de Botanique, Université de Liège, Liege, Belgium.
| |
Collapse
|
39
|
The accumulation of assembly intermediates of the mitochondrial complex I matrix arm is reduced by limiting glucose uptake in a neuronal-like model of MELAS syndrome. Biochim Biophys Acta Mol Basis Dis 2018; 1864:1596-1608. [PMID: 29454073 DOI: 10.1016/j.bbadis.2018.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 02/06/2023]
Abstract
Ketogenic diet (KD) which combined carbohydrate restriction and the addition of ketone bodies has emerged as an alternative metabolic intervention used as an anticonvulsant therapy or to treat different types of neurological or mitochondrial disorders including MELAS syndrome. MELAS syndrome is a severe mitochondrial disease mainly due to the m.3243A > G mitochondrial DNA mutation. The broad success of KD is due to multiple beneficial mechanisms with distinct effects of very low carbohydrates and ketones. To evaluate the metabolic part of carbohydrate restriction, transmitochondrial neuronal-like cybrid cells carrying the m.3243A > G mutation, shown to be associated with a severe complex I deficiency was exposed during 3 weeks to glucose restriction. Mitochondrial enzyme defects were combined with an accumulation of complex I (CI) matrix intermediates in the untreated mutant cells, leading to a drastic reduction in CI driven respiration. The severe reduction of CI was also paralleled in post-mortem brain tissue of a MELAS patient carrying high mutant load. Importantly, lowering significantly glucose concentration in cell culture improved CI assembly with a significant reduction of matrix assembly intermediates and respiration capacities were restored in a sequential manner. In addition, OXPHOS protein expression and mitochondrial DNA copy number were significantly increased in mutant cells exposed to glucose restriction. The accumulation of CI matrix intermediates appeared as a hallmark of MELAS pathophysiology highlighting a critical pathophysiological mechanism involving CI disassembly, which can be alleviated by lowering glucose fuelling and the induction of mitochondrial biogenesis, emphasizing the usefulness of metabolic interventions in MELAS syndrome.
Collapse
|
40
|
Abstract
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP. The three proton pumping complexes of the electron transfer chain are NADH-ubiquinone oxidoreductase or complex I, ubiquinone-cytochrome c oxidoreductase or complex III, and cytochrome c oxidase or complex IV. Succinate dehydrogenase or complex II does not pump protons, but contributes reduced ubiquinone. The structures of complex II, III and IV were determined by x-ray crystallography several decades ago, but complex I and ATP synthase have only recently started to reveal their secrets by advances in x-ray crystallography and cryo-electron microscopy. The complexes I, III and IV occur to a certain extent as supercomplexes in the membrane, the so-called respirasomes. Several hypotheses exist about their function. Recent cryo-electron microscopy structures show the architecture of the respirasome with near-atomic detail. ATP synthase occurs as dimers in the inner mitochondrial membrane, which by their curvature are responsible for the folding of the membrane into cristae and thus for the huge increase in available surface that makes mitochondria the efficient energy plants of the eukaryotic cell.
Collapse
Affiliation(s)
- Joana S Sousa
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Edoardo D'Imprima
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| |
Collapse
|
41
|
Angerer H, Schönborn S, Gorka J, Bahr U, Karas M, Wittig I, Heidler J, Hoffmann J, Morgner N, Zickermann V. Acyl modification and binding of mitochondrial ACP to multiprotein complexes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1913-1920. [PMID: 28802701 DOI: 10.1016/j.bbamcr.2017.08.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 01/06/2023]
Abstract
The mitochondrial acyl carrier protein (ACPM/NDUFAB1) is a central element of the mitochondrial fatty acid synthesis type II machinery. Originally ACPM was detected as a subunit of respiratory complex I but the reason for the association with the large enzyme complex remained elusive. Complex I from the aerobic yeast Yarrowia lipolytica comprises two different ACPMs, ACPM1 and ACPM2. They are anchored to the protein complex by LYR (leucine-tyrosine-arginine) motif containing protein (LYRM) subunits LYRM3 (NDUFB9) and LYRM6 (NDUFA6). The ACPM1-LYRM6 and ACPM2-LYRM3 modules are essential for complex I activity and assembly/stability, respectively. We show that in addition to the complex I bound fraction, ACPM1 is present as a free matrix protein and in complex with the soluble LYRM4(ISD11)/NFS1 complex implicated in Fe-S cluster biogenesis. We show that the presence of a long acyl chain bound to the phosphopantetheine cofactor is important for docking ACPMs to protein complexes and we propose that association of ACPMs and LYRMs is universally based on a new protein-protein interaction motif.
Collapse
Affiliation(s)
- Heike Angerer
- Goethe University Frankfurt, Medical School, Institute of Biochemistry II, Structural Bioenergetics Group, Max-von-Laue Str. 9, 60438 Frankfurt, Germany.
| | - Stefan Schönborn
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Jan Gorka
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Ute Bahr
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Michael Karas
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Ilka Wittig
- Functional Proteomics, SFB 815 core unit, Goethe-University Frankfurt, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Juliana Heidler
- Functional Proteomics, SFB 815 core unit, Goethe-University Frankfurt, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Jan Hoffmann
- Goethe University Frankfurt, Institute of Physical and Theoretical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Nina Morgner
- Goethe University Frankfurt, Institute of Physical and Theoretical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Volker Zickermann
- Goethe University Frankfurt, Medical School, Institute of Biochemistry II, Structural Bioenergetics Group, Max-von-Laue Str. 9, 60438 Frankfurt, Germany; Cluster of Excellence Macromolecular Complexes, Goethe University Frankfurt, Germany.
| |
Collapse
|
42
|
Cory SA, Van Vranken JG, Brignole EJ, Patra S, Winge DR, Drennan CL, Rutter J, Barondeau DP. Structure of human Fe-S assembly subcomplex reveals unexpected cysteine desulfurase architecture and acyl-ACP-ISD11 interactions. Proc Natl Acad Sci U S A 2017; 114:E5325-E5334. [PMID: 28634302 PMCID: PMC5502623 DOI: 10.1073/pnas.1702849114] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In eukaryotes, sulfur is mobilized for incorporation into multiple biosynthetic pathways by a cysteine desulfurase complex that consists of a catalytic subunit (NFS1), LYR protein (ISD11), and acyl carrier protein (ACP). This NFS1-ISD11-ACP (SDA) complex forms the core of the iron-sulfur (Fe-S) assembly complex and associates with assembly proteins ISCU2, frataxin (FXN), and ferredoxin to synthesize Fe-S clusters. Here we present crystallographic and electron microscopic structures of the SDA complex coupled to enzyme kinetic and cell-based studies to provide structure-function properties of a mitochondrial cysteine desulfurase. Unlike prokaryotic cysteine desulfurases, the SDA structure adopts an unexpected architecture in which a pair of ISD11 subunits form the dimeric core of the SDA complex, which clarifies the critical role of ISD11 in eukaryotic assemblies. The different quaternary structure results in an incompletely formed substrate channel and solvent-exposed pyridoxal 5'-phosphate cofactor and provides a rationale for the allosteric activator function of FXN in eukaryotic systems. The structure also reveals the 4'-phosphopantetheine-conjugated acyl-group of ACP occupies the hydrophobic core of ISD11, explaining the basis of ACP stabilization. The unexpected architecture for the SDA complex provides a framework for understanding interactions with acceptor proteins for sulfur-containing biosynthetic pathways, elucidating mechanistic details of eukaryotic Fe-S cluster biosynthesis, and clarifying how defects in Fe-S cluster assembly lead to diseases such as Friedreich's ataxia. Moreover, our results support a lock-and-key model in which LYR proteins associate with acyl-ACP as a mechanism for fatty acid biosynthesis to coordinate the expression, Fe-S cofactor maturation, and activity of the respiratory complexes.
Collapse
Affiliation(s)
- Seth A Cory
- Department of Chemistry, Texas A&M University, College Station, TX 77842
| | - Jonathan G Van Vranken
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Edward J Brignole
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Shachin Patra
- Department of Chemistry, Texas A&M University, College Station, TX 77842
| | - Dennis R Winge
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Catherine L Drennan
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112
- Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - David P Barondeau
- Department of Chemistry, Texas A&M University, College Station, TX 77842;
| |
Collapse
|
43
|
Scanlon DP, Bah A, Krzeminski M, Zhang W, Leduc-Pessah HL, Dong YN, Forman-Kay JD, Salter MW. An evolutionary switch in ND2 enables Src kinase regulation of NMDA receptors. Nat Commun 2017; 8:15220. [PMID: 28508887 PMCID: PMC5440837 DOI: 10.1038/ncomms15220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/10/2017] [Indexed: 12/22/2022] Open
Abstract
The non-receptor tyrosine kinase Src is a key signalling hub for upregulating the function of N-methyl D-aspartate receptors (NMDARs). Src is anchored within the NMDAR complex via NADH dehydrogenase subunit 2 (ND2), a mitochondrially encoded adaptor protein. The interacting regions between Src and ND2 have been broadly identified, but the interaction between ND2 and the NMDAR has remained elusive. Here we generate a homology model of ND2 and dock it onto the NMDAR via the transmembrane domain of GluN1. This interaction is enabled by the evolutionary loss of three helices in bilaterian ND2 proteins compared to their ancestral homologues. We experimentally validate our model and demonstrate that blocking this interaction with an ND2 fragment identified in our experimental studies prevents Src-mediated upregulation of NMDAR currents in neurons. Our findings establish the mode of interaction between an NMDAR accessory protein with one of the core subunits of the receptor. N-methyl D-aspartate receptor (NMDAR) activity is modulated by Src tyrosine kinase via the mitochondrial protein NADH dehydrogenase subunit 2 (ND2). Here the authors show that ND2 interacts with the transmembrane region of NMDAR GluN1 subunit, a process that is crucial for Src regulation of NMDAR activity.
Collapse
Affiliation(s)
- David P Scanlon
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Alaji Bah
- Program in Molecular Medicine, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Mickaël Krzeminski
- Program in Molecular Medicine, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Wenbo Zhang
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Heather L Leduc-Pessah
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Yi Na Dong
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Julie D Forman-Kay
- Program in Molecular Medicine, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Michael W Salter
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| |
Collapse
|
44
|
Bridges HR, Mohammed K, Harbour ME, Hirst J. Subunit NDUFV3 is present in two distinct isoforms in mammalian complex I. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2017; 1858:197-207. [PMID: 27940020 PMCID: PMC5293009 DOI: 10.1016/j.bbabio.2016.12.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 11/29/2016] [Accepted: 12/07/2016] [Indexed: 01/10/2023]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) is the first enzyme of the electron transport chain in mammalian mitochondria. Extensive proteomic and structural analyses of complex I from Bos taurus heart mitochondria have shown it comprises 45 subunits encoded on both the nuclear and mitochondrial genomes; 44 of them are different and one is present in two copies. The bovine heart enzyme has provided a model for studying the composition of complex I in other mammalian species, including humans, but the possibility of additional subunits or isoforms in other species or tissues has not been explored. Here, we describe characterization of the complexes I purified from five rat tissues and from a rat hepatoma cell line. We identify a~50kDa isoform of subunit NDUFV3, for which the canonical isoform is only ~10kDa in size. We combine LC-MS and MALDI-TOF mass spectrometry data from two different purification methods (chromatography and immuno-purification) with information from blue native PAGE analyses to show the long isoform is present in the mature complex, but at substoichiometric levels. It is also present in complex I in cultured human cells. We describe evidence that the long isoform is more abundant in both the mitochondria and purified complexes from brain (relative to in heart, liver, kidney and skeletal muscle) and more abundant still in complex I in cultured cells. We propose that the long 50kDa isoform competes with its canonical 10kDa counterpart for a common binding site on the flavoprotein domain of complex I.
Collapse
Affiliation(s)
- Hannah R Bridges
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K
| | - Khairunnisa Mohammed
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K
| | - Michael E Harbour
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K..
| |
Collapse
|
45
|
The Assembly Pathway of Mitochondrial Respiratory Chain Complex I. Cell Metab 2017; 25:128-139. [PMID: 27720676 DOI: 10.1016/j.cmet.2016.09.002] [Citation(s) in RCA: 281] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/21/2016] [Accepted: 09/10/2016] [Indexed: 11/20/2022]
Abstract
Mitochondrial complex I is the largest integral membrane enzyme of the respiratory chain and consists of 44 different subunits encoded in the mitochondrial and nuclear genome. Its biosynthesis is a highly complicated and multifaceted process involving at least 14 additional assembly factors. How these subunits assemble into a functional complex I and where the assembly factors come into play is largely unknown. Here, we applied a dynamic complexome profiling approach to elucidate the assembly of human mitochondrial complex I and its further incorporation into respiratory chain supercomplexes. We delineate the stepwise incorporation of all but one subunit into a series of distinct assembly intermediates and their association with known and putative assembly factors, which had not been implicated in this process before. The resulting detailed and comprehensive model of complex I assembly is fully consistent with recent structural data and the remarkable modular architecture of this multiprotein complex.
Collapse
|
46
|
Papa F, Lippolis R, Sardaro N, Gnoni A, Scacco S. All trans retinoic acid depresses the content and activity of the mitochondrial ATP synthase in human keratinocytes. Biochem Biophys Res Commun 2017; 482:301-304. [PMID: 27856255 DOI: 10.1016/j.bbrc.2016.11.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022]
Abstract
Proteomic analysis shows that treatment of keratinocytes cultures with all trans retinoic acid (ATRA), under condition in which it inhibits cell growth, results in marked decrease of the level of the F1-β subunit of the catalytic sector of the mitochondrial FoF1 ATP synthase complex. Enzymatic analysis shows in ATRA-treated keratinocytes a consistent depression of the ATPase activity, with decreased olygomycin sensitivity, indicating an overall alteration of the ATP synthase complex. These findings, together with the previously reported inhibition of respiratory complex I, show that depression of the activity of oxidative phosphorylation enzymes is involved in the cell growth inhibitory action of ATRA.
Collapse
Affiliation(s)
- F Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University 'A. Moro', Bari, Italy
| | - R Lippolis
- Institute of Biomembranes and Bioenergetics, Italian National Research Council (CNR), Via G. Amendola 165/A, Italy
| | - N Sardaro
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University 'A. Moro', Bari, Italy
| | - A Gnoni
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University 'A. Moro', Bari, Italy
| | - S Scacco
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University 'A. Moro', Bari, Italy.
| |
Collapse
|
47
|
Fiedorczuk K, Letts JA, Degliesposti G, Kaszuba K, Skehel M, Sazanov LA. Atomic structure of the entire mammalian mitochondrial complex I. Nature 2016; 538:406-410. [PMID: 27595392 DOI: 10.1038/nature19794] [Citation(s) in RCA: 359] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 08/26/2016] [Indexed: 12/15/2022]
Abstract
Mitochondrial complex I (also known as NADH:ubiquinone oxidoreductase) contributes to cellular energy production by transferring electrons from NADH to ubiquinone coupled to proton translocation across the membrane. It is the largest protein assembly of the respiratory chain with a total mass of 970 kilodaltons. Here we present a nearly complete atomic structure of ovine (Ovis aries) mitochondrial complex I at 3.9 Å resolution, solved by cryo-electron microscopy with cross-linking and mass-spectrometry mapping experiments. All 14 conserved core subunits and 31 mitochondria-specific supernumerary subunits are resolved within the L-shaped molecule. The hydrophilic matrix arm comprises flavin mononucleotide and 8 iron-sulfur clusters involved in electron transfer, and the membrane arm contains 78 transmembrane helices, mostly contributed by antiporter-like subunits involved in proton translocation. Supernumerary subunits form an interlinked, stabilizing shell around the conserved core. Tightly bound lipids (including cardiolipins) further stabilize interactions between the hydrophobic subunits. Subunits with possible regulatory roles contain additional cofactors, NADPH and two phosphopantetheine molecules, which are shown to be involved in inter-subunit interactions. We observe two different conformations of the complex, which may be related to the conformationally driven coupling mechanism and to the active-deactive transition of the enzyme. Our structure provides insight into the mechanism, assembly, maturation and dysfunction of mitochondrial complex I, and allows detailed molecular analysis of disease-causing mutations.
Collapse
Affiliation(s)
- Karol Fiedorczuk
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria.,MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, UK
| | - James A Letts
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | | | - Karol Kaszuba
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | - Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge CB2 OQH, UK
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| |
Collapse
|
48
|
Kastaniotis AJ, Autio KJ, Kerätär JM, Monteuuis G, Mäkelä AM, Nair RR, Pietikäinen LP, Shvetsova A, Chen Z, Hiltunen JK. Mitochondrial fatty acid synthesis, fatty acids and mitochondrial physiology. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:39-48. [PMID: 27553474 DOI: 10.1016/j.bbalip.2016.08.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 07/20/2016] [Accepted: 08/17/2016] [Indexed: 02/07/2023]
Abstract
Mitochondria and fatty acids are tightly connected to a multiplicity of cellular processes that go far beyond mitochondrial fatty acid metabolism. In line with this view, there is hardly any common metabolic disorder that is not associated with disturbed mitochondrial lipid handling. Among other aspects of mitochondrial lipid metabolism, apparently all eukaryotes are capable of carrying out de novo fatty acid synthesis (FAS) in this cellular compartment in an acyl carrier protein (ACP)-dependent manner. The dual localization of FAS in eukaryotic cells raises the questions why eukaryotes have maintained the FAS in mitochondria in addition to the "classic" cytoplasmic FAS and what the products are that cannot be substituted by delivery of fatty acids of extramitochondrial origin. The current evidence indicates that mitochondrial FAS is essential for cellular respiration and mitochondrial biogenesis. Although both β-oxidation and FAS utilize thioester chemistry, CoA acts as acyl-group carrier in the breakdown pathway whereas ACP assumes this role in the synthetic direction. This arrangement metabolically separates these two pathways running towards opposite directions and prevents futile cycling. A role of this pathway in mitochondrial metabolic sensing has recently been proposed. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
Collapse
Affiliation(s)
- Alexander J Kastaniotis
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland.
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Juha M Kerätär
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Geoffray Monteuuis
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anne M Mäkelä
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Remya R Nair
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Laura P Pietikäinen
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Antonina Shvetsova
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Zhijun Chen
- State Key Laboratory of Supramolecular Structure and Materials and Institute of Theoretical Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland; State Key Laboratory of Supramolecular Structure and Materials and Institute of Theoretical Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China.
| |
Collapse
|
49
|
Van Vranken JG, Jeong MY, Wei P, Chen YC, Gygi SP, Winge DR, Rutter J. The mitochondrial acyl carrier protein (ACP) coordinates mitochondrial fatty acid synthesis with iron sulfur cluster biogenesis. eLife 2016; 5. [PMID: 27540631 PMCID: PMC4991935 DOI: 10.7554/elife.17828] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/22/2016] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial fatty acid synthesis (FASII) and iron sulfur cluster (FeS) biogenesis are both vital biosynthetic processes within mitochondria. In this study, we demonstrate that the mitochondrial acyl carrier protein (ACP), which has a well-known role in FASII, plays an unexpected and evolutionarily conserved role in FeS biogenesis. ACP is a stable and essential subunit of the eukaryotic FeS biogenesis complex. In the absence of ACP, the complex is destabilized resulting in a profound depletion of FeS throughout the cell. This role of ACP depends upon its covalently bound 4’-phosphopantetheine (4-PP)-conjugated acyl chain to support maximal cysteine desulfurase activity. Thus, it is likely that ACP is not simply an obligate subunit but also exploits the 4-PP-conjugated acyl chain to coordinate mitochondrial fatty acid and FeS biogenesis. DOI:http://dx.doi.org/10.7554/eLife.17828.001 Like animals and plants, yeast cells contain structures called mitochondria. These structures are commonly referred to as the powerhouses of the cell because they provide much of the energy that cells need to survive. All mitochondria contain a protein called acyl carrier protein (ACP), which cells need in order to live. The ACP protein has a number of known roles including manufacturing the molecules that make up certain fats and helping to organise other proteins that are important for energy production. However, neither of these roles explain why yeast cells require ACP because the other proteins required for these processes are not required for survival. Mitochondria are also the sites where iron and sulfur atoms are joined together to make the iron sulfur clusters that many proteins need in order to carry out their roles. Van Vranken, Jeong et al. now show that the ACP protein associates with a molecular machine that makes iron sulfur clusters in the mitochondria of budding yeast cells. The experiments show that this interaction is needed to produce iron sulfur clusters, and without it the other proteins involved in the process are not able to work together. Since iron sulfur clusters are essential for life, this could explain why cells cannot survive without ACP. Van Vranken et al. also showed that ACP is only able to efficiently produce iron sulfur clusters when a chemical called a “4-PP-conjugated acyl chain” is attached to it. It is possible to separate the activity of ACP in making iron sulfur clusters from its previously known roles. Van Vranken et al. suggest that the addition of the 4-PP-conjugated acyl chain to ACP may help to balance the use of ACP between its different activities. Moving forward, Van Vranken et al. hope to determine the structure of ACP in more detail to understand how it contributes to iron sulfur cluster formation, and why this single protein has evolved to perform so many distinct roles. DOI:http://dx.doi.org/10.7554/eLife.17828.002
Collapse
Affiliation(s)
- Jonathan G Van Vranken
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Mi-Young Jeong
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States.,Department of Medicine, University of Utah School of Medicine, Salt Lake City, United States
| | - Peng Wei
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Yu-Chan Chen
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Steven P Gygi
- Department of Cell Biology, Harvard University School of Medicine, Boston, United States
| | - Dennis R Winge
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States.,Department of Medicine, University of Utah School of Medicine, Salt Lake City, United States
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States.,Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, United States
| |
Collapse
|
50
|
Sheeran FL, Pepe S. Posttranslational modifications and dysfunction of mitochondrial enzymes in human heart failure. Am J Physiol Endocrinol Metab 2016; 311:E449-60. [PMID: 27406740 DOI: 10.1152/ajpendo.00127.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/28/2016] [Indexed: 11/22/2022]
Abstract
Deficiency of energy supply is a major complication contributing to the syndrome of heart failure (HF). Because the concurrent activity profile of mitochondrial bioenergetic enzymes has not been studied collectively in human HF, our aim was to examine the mitochondrial enzyme defects in left ventricular myocardium obtained from explanted end-stage failing hearts. Compared with nonfailing donor hearts, activity rates of complexes I and IV and the Krebs cycle enzymes isocitrate dehydrogenase, malate dehydrogenase, and aconitase were lower in HF, as determined spectrophotometrically. However, activity rates of complexes II and III and citrate synthase did not differ significantly between the two groups. Protein expression, determined by Western blotting, did not differ between the groups, implying posttranslational perturbation. In the face of diminished total glutathione and coenzyme Q10 levels, oxidative modification was explored as an underlying cause of enzyme dysfunction. Of the three oxidative modifications measured, protein carbonylation was increased significantly by 31% in HF (P < 0.01; n = 18), whereas levels of 4-hydroxynonenal and protein nitration, although elevated, did not differ. Isolation of complexes I and IV and F1FoATP synthase by immunocapture revealed that proteins containing iron-sulphur or heme redox centers were targets of oxidative modification. Energy deficiency in end-stage failing human left ventricle involves impaired activity of key electron transport chain and Krebs cycle enzymes without altered expression of protein levels. Augmented oxidative modification of crucial enzyme subunit structures implicates dysfunction due to diminished capacity for management of mitochondrial reactive oxygen species, thus contributing further to reduced bioenergetics in human HF.
Collapse
Affiliation(s)
- Freya L Sheeran
- Heart Research, Clinical Sciences, Murdoch Children's Research Institute, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia; and Department of Surgery at Alfred Hospital, Monash University, Melbourne, Australia
| | - Salvatore Pepe
- Heart Research, Clinical Sciences, Murdoch Children's Research Institute, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia; and Department of Surgery at Alfred Hospital, Monash University, Melbourne, Australia
| |
Collapse
|