1
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Garcia GC, Gupta K, Bartol TM, Sejnowski TJ, Rangamani P. Mitochondrial morphology governs ATP production rate. J Gen Physiol 2023; 155:e202213263. [PMID: 37615622 PMCID: PMC10450615 DOI: 10.1085/jgp.202213263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 03/21/2023] [Accepted: 07/07/2023] [Indexed: 08/25/2023] Open
Abstract
Life is based on energy conversion. In particular, in the nervous system, significant amounts of energy are needed to maintain synaptic transmission and homeostasis. To a large extent, neurons depend on oxidative phosphorylation in mitochondria to meet their high energy demand. For a comprehensive understanding of the metabolic demands in neuronal signaling, accurate models of ATP production in mitochondria are required. Here, we present a thermodynamically consistent model of ATP production in mitochondria based on previous work. The significant improvement of the model is that the reaction rate constants are set such that detailed balance is satisfied. Moreover, using thermodynamic considerations, the dependence of the reaction rate constants on membrane potential, pH, and substrate concentrations are explicitly provided. These constraints assure that the model is physically plausible. Furthermore, we explore different parameter regimes to understand in which conditions ATP production or its export are the limiting steps in making ATP available in the cytosol. The outcomes reveal that, under the conditions used in our simulations, ATP production is the limiting step and not its export. Finally, we performed spatial simulations with nine 3-D realistic mitochondrial reconstructions and linked the ATP production rate in the cytosol with morphological features of the organelles.
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Affiliation(s)
- Guadalupe C. Garcia
- Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Kavya Gupta
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Thomas M. Bartol
- Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Terrence J. Sejnowski
- Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, USA
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2
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Frigo E, Tommasin L, Lippe G, Carraro M, Bernardi P. The Haves and Have-Nots: The Mitochondrial Permeability Transition Pore across Species. Cells 2023; 12:1409. [PMID: 37408243 PMCID: PMC10216546 DOI: 10.3390/cells12101409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 07/07/2023] Open
Abstract
The demonstration that F1FO (F)-ATP synthase and adenine nucleotide translocase (ANT) can form Ca2+-activated, high-conductance channels in the inner membrane of mitochondria from a variety of eukaryotes led to renewed interest in the permeability transition (PT), a permeability increase mediated by the PT pore (PTP). The PT is a Ca2+-dependent permeability increase in the inner mitochondrial membrane whose function and underlying molecular mechanisms have challenged scientists for the last 70 years. Although most of our knowledge about the PTP comes from studies in mammals, recent data obtained in other species highlighted substantial differences that could be perhaps attributed to specific features of F-ATP synthase and/or ANT. Strikingly, the anoxia and salt-tolerant brine shrimp Artemia franciscana does not undergo a PT in spite of its ability to take up and store Ca2+ in mitochondria, and the anoxia-resistant Drosophila melanogaster displays a low-conductance, selective Ca2+-induced Ca2+ release channel rather than a PTP. In mammals, the PT provides a mechanism for the release of cytochrome c and other proapoptotic proteins and mediates various forms of cell death. In this review, we cover the features of the PT (or lack thereof) in mammals, yeast, Drosophila melanogaster, Artemia franciscana and Caenorhabditis elegans, and we discuss the presence of the intrinsic pathway of apoptosis and of other forms of cell death. We hope that this exercise may help elucidate the function(s) of the PT and its possible role in evolution and inspire further tests to define its molecular nature.
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Affiliation(s)
- Elena Frigo
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
| | - Ludovica Tommasin
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
| | - Giovanna Lippe
- Department of Medicine, University of Udine, Piazzale Kolbe 4, I-33100 Udine, Italy;
| | - Michela Carraro
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
| | - Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
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3
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Endlicher R, Drahota Z, Štefková K, Červinková Z, Kučera O. The Mitochondrial Permeability Transition Pore-Current Knowledge of Its Structure, Function, and Regulation, and Optimized Methods for Evaluating Its Functional State. Cells 2023; 12:cells12091273. [PMID: 37174672 PMCID: PMC10177258 DOI: 10.3390/cells12091273] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
The mitochondrial permeability transition pore (MPTP) is a calcium-dependent, ion non-selective membrane pore with a wide range of functions. Although the MPTP has been studied for more than 50 years, its molecular structure remains unclear. Short-term (reversible) opening of the MPTP protects cells from oxidative damage and enables the efflux of Ca2+ ions from the mitochondrial matrix and cell signaling. However, long-term (irreversible) opening induces processes leading to cell death. Ca2+ ions, reactive oxygen species, and changes in mitochondrial membrane potential regulate pore opening. The sensitivity of the pore to Ca2+ ions changes as an organism ages, and MPTP opening plays a key role in the pathogenesis of many diseases. Most studies of the MPTP have focused on elucidating its molecular structure. However, understanding the mechanisms that will inhibit the MPTP may improve the treatment of diseases associated with its opening. To evaluate the functional state of the MPTP and its inhibitors, it is therefore necessary to use appropriate methods that provide reproducible results across laboratories. This review summarizes our current knowledge of the function and regulation of the MPTP. The latter part of the review introduces two optimized methods for evaluating the functional state of the pore under standardized conditions.
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Affiliation(s)
- René Endlicher
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, 500 03 Hradec Králové, Czech Republic
- Department of Anatomy, Faculty of Medicine in Hradec Králové, Charles University, 500 03 Hradec Králové, Czech Republic
| | - Zdeněk Drahota
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, 500 03 Hradec Králové, Czech Republic
- Institute of Physiology, Czech Academy of Sciences, 142 00 Prague, Czech Republic
| | - Kateřina Štefková
- Department of Anatomy, Faculty of Medicine in Hradec Králové, Charles University, 500 03 Hradec Králové, Czech Republic
| | - Zuzana Červinková
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, 500 03 Hradec Králové, Czech Republic
| | - Otto Kučera
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, 500 03 Hradec Králové, Czech Republic
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4
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Pedriali G, Ramaccini D, Bouhamida E, Branchini A, Turrin G, Tonet E, Scala A, Patergnani S, Pinotti M, Trapella C, Giorgi C, Tremoli E, Campo G, Morciano G, Pinton P. 1,3,8-Triazaspiro[4.5]decane Derivatives Inhibit Permeability Transition Pores through a FO-ATP Synthase c Subunit Glu119-Independent Mechanism That Prevents Oligomycin A-Related Side Effects. Int J Mol Sci 2023; 24:ijms24076191. [PMID: 37047160 PMCID: PMC10094280 DOI: 10.3390/ijms24076191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/17/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Permeability transition pore (PTP) molecular composition and activity modulation have been a matter of research for several years, especially due to their importance in ischemia reperfusion injury (IRI). Notably, c subunit of ATP synthase (Csub) has been identified as one of the PTP-forming proteins and as a target for cardioprotection. Oligomycin A is a well-known Csub interactor that has been chemically modified in-depth for proposed new pharmacological approaches against cardiac reperfusion injury. Indeed, by taking advantage of its scaffold and through focused chemical improvements, innovative Csub-dependent PTP inhibitors (1,3,8-Triazaspiro[4.5]decane) have been synthetized in the past. Interestingly, four critical amino acids have been found to be involved in Oligomycin A-Csub binding in yeast. However, their position on the human sequence is unknown, as is their function in PTP inhibition. The aims of this study are to (i) identify for the first time the topologically equivalent residues in the human Csub sequence; (ii) provide their in vitro validation in Oligomycin A-mediated PTP inhibition and (iii) understand their relevance in the binding of 1,3,8-Triazaspiro[4.5]decane small molecules, as Oligomycin A derivatives, in order to provide insights into Csub interactions. Notably, in this study we demonstrated that 1,3,8-Triazaspiro[4.5]decane derivatives inhibit permeability transition pores through a FO-ATP synthase c subunit Glu119-independent mechanism that prevents Oligomycin A-related side effects.
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5
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Bernardi P, Carraro M, Lippe G. The mitochondrial permeability transition: Recent progress and open questions. FEBS J 2022; 289:7051-7074. [PMID: 34710270 PMCID: PMC9787756 DOI: 10.1111/febs.16254] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 10/27/2021] [Indexed: 01/13/2023]
Abstract
Major progress has been made in defining the basis of the mitochondrial permeability transition, a Ca2+ -dependent permeability increase of the inner membrane that has puzzled mitochondrial research for almost 70 years. Initially considered an artefact of limited biological interest by most, over the years the permeability transition has raised to the status of regulator of mitochondrial ion homeostasis and of druggable effector mechanism of cell death. The permeability transition is mediated by opening of channel(s) modulated by matrix cyclophilin D, the permeability transition pore(s) (PTP). The field has received new impulse (a) from the hypothesis that the PTP may originate from a Ca2+ -dependent conformational change of F-ATP synthase and (b) from the reevaluation of the long-standing hypothesis that it originates from the adenine nucleotide translocator (ANT). Here, we provide a synthetic account of the structure of ANT and F-ATP synthase to discuss potential and controversial mechanisms through which they may form high-conductance channels; and review some intriguing findings from the wealth of early studies of PTP modulation that still await an explanation. We hope that this review will stimulate new experiments addressing the many outstanding problems, and thus contribute to the eventual solution of the puzzle of the permeability transition.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
| | - Michela Carraro
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
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6
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Zhang L, Liu Y, Zhou R, He B, Wang W, Zhang B. Cyclophilin D: Guardian or Executioner for Tumor Cells? Front Oncol 2022; 12:939588. [PMID: 35860554 PMCID: PMC9289278 DOI: 10.3389/fonc.2022.939588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
Cyclophilin D (CypD) is a peptide-proline cis-trans isomerase (PPIase) distributed in the mitochondrial matrix. CypD regulates the opening of the mitochondrial permeability conversion pore (mPTP) and mitochondrial bioenergetics through PPIase activity or interaction with multiple binding partners in mitochondria. CypD initially attracted attention due to its regulation of mPTP overopening-mediated cell death. However, recent studies on the effects of CypD on tumors have shown conflicting results. Although CypD has been proven to promote the aerobic glycolysis in tumor cells, its regulation of malignant characteristics such as the survival, invasion and drug resistance of tumor cells remains controversial. Here, we elaborate the main biological functions of CypD and its relationships with tumor progression identified in recent years, focusing on the dual role of CypD in tumors.
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Affiliation(s)
- Ling Zhang
- School of Nursing, Jining Medical University, Jining, China
- *Correspondence: Bin Zhang, ; Ling Zhang,
| | - Yi Liu
- School of Nursing, Jining Medical University, Jining, China
- School of Public Health, North China University of Science and Technology, Tangshan, China
| | - Rou Zhou
- Department of Laboratory Medicine, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, China
| | - Baoyu He
- Department of Laboratory Medicine, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, China
| | - Wenjun Wang
- School of Nursing, Jining Medical University, Jining, China
| | - Bin Zhang
- Department of Laboratory Medicine, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, China
- Institute of Forensic Medicine and Laboratory Medicine, Jining Medical University, Jining, China
- *Correspondence: Bin Zhang, ; Ling Zhang,
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7
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Mitochondrial Ca 2+ Homeostasis: Emerging Roles and Clinical Significance in Cardiac Remodeling. Int J Mol Sci 2022; 23:ijms23063025. [PMID: 35328444 PMCID: PMC8954803 DOI: 10.3390/ijms23063025] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are the sites of oxidative metabolism in eukaryotes where the metabolites of sugars, fats, and amino acids are oxidized to harvest energy. Notably, mitochondria store Ca2+ and work in synergy with organelles such as the endoplasmic reticulum and extracellular matrix to control the dynamic balance of Ca2+ concentration in cells. Mitochondria are the vital organelles in heart tissue. Mitochondrial Ca2+ homeostasis is particularly important for maintaining the physiological and pathological mechanisms of the heart. Mitochondrial Ca2+ homeostasis plays a key role in the regulation of cardiac energy metabolism, mechanisms of death, oxygen free radical production, and autophagy. The imbalance of mitochondrial Ca2+ balance is closely associated with cardiac remodeling. The mitochondrial Ca2+ uniporter (mtCU) protein complex is responsible for the uptake and release of mitochondrial Ca2+ and regulation of Ca2+ homeostasis in mitochondria and consequently, in cells. This review summarizes the mechanisms of mitochondrial Ca2+ homeostasis in physiological and pathological cardiac remodeling and the regulatory effects of the mitochondrial calcium regulatory complex on cardiac energy metabolism, cell death, and autophagy, and also provides the theoretical basis for mitochondrial Ca2+ as a novel target for the treatment of cardiovascular diseases.
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8
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Johar D, Elmehrath AO, Khalil RM, Elberry MH, Zaky S, Shalabi SA, Bernstein LH. Protein networks linking Warburg and reverse Warburg effects to cancer cell metabolism. Biofactors 2021; 47:713-728. [PMID: 34453457 DOI: 10.1002/biof.1768] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/22/2021] [Indexed: 12/11/2022]
Abstract
It was 80 years after the Otto Warburg discovery of aerobic glycolysis, a major hallmark in the understanding of cancer. The Warburg effect is the preference of cancer cell for glycolysis that produces lactate even when sufficient oxygen is provided. "reverse Warburg effect" refers to the interstitial tissue communications with adjacent epithelium, that in the process of carcinogenesis, is needed to be explored. Among these cell-cell communications, the contact between epithelial cells; between epithelial cells and matrix; and between fibroblasts and inflammatory cells in the underlying matrix. Cancer involves dysregulation of Warburg and reverse Warburg cellular metabolic pathways. How these gene and protein-based regulatory mechanisms have functioned has been the basis for this review. The importance of the Warburg in oxidative phosphorylation suppression, with increased glycolysis in cancer growth and proliferation is emphasized. Studies that are directed at pathways that would be expected to shift cell metabolism to an increased oxidation and to a decrease in glycolysis are emphasized. Key enzymes required for oxidative phosphorylation, and affect the inhibition of fatty acid metabolism and glutamine dependence are conferred. The findings are of special interest to cancer pharmacotherapy. Studies described in this review are concerned with the effects of therapeutic modalities that are intimately related to the Warburg effect. These interactions described may be helpful as adjuvant therapy in controlling the process of proliferation and metastasis.
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Affiliation(s)
- Dina Johar
- Department of Biochemistry and Nutrition, Faculty of Women for Arts, Sciences and Education, Ain Shams University, Heliopolis, Cairo, Egypt
| | | | - Rania M Khalil
- Department of Biochemistry, Pharmacy College, Delta University for Science and Technology, Gamasa, Egypt
| | - Mostafa H Elberry
- Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Samy Zaky
- Hepatogastroenterology and Infectious Diseases, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
| | - Samy A Shalabi
- Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
- Consultant Pathologist, Kuwait, Kuwait
| | - Larry H Bernstein
- Emeritus Prof. Department of Pathology, Yale University, Connecticut, USA
- Triplex Consulting Pharmaceuticals, 54 Firethorn Lane Northampton, MA 01060, USA
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9
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Carrer A, Tommasin L, Šileikytė J, Ciscato F, Filadi R, Urbani A, Forte M, Rasola A, Szabò I, Carraro M, Bernardi P. Defining the molecular mechanisms of the mitochondrial permeability transition through genetic manipulation of F-ATP synthase. Nat Commun 2021; 12:4835. [PMID: 34376679 PMCID: PMC8355262 DOI: 10.1038/s41467-021-25161-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022] Open
Abstract
F-ATP synthase is a leading candidate as the mitochondrial permeability transition pore (PTP) but the mechanism(s) leading to channel formation remain undefined. Here, to shed light on the structural requirements for PTP formation, we test cells ablated for g, OSCP and b subunits, and ρ0 cells lacking subunits a and A6L. Δg cells (that also lack subunit e) do not show PTP channel opening in intact cells or patch-clamped mitoplasts unless atractylate is added. Δb and ΔOSCP cells display currents insensitive to cyclosporin A but inhibited by bongkrekate, suggesting that the adenine nucleotide translocator (ANT) can contribute to channel formation in the absence of an assembled F-ATP synthase. Mitoplasts from ρ0 mitochondria display PTP currents indistinguishable from their wild-type counterparts. In this work, we show that peripheral stalk subunits are essential to turn the F-ATP synthase into the PTP and that the ANT provides mitochondria with a distinct permeability pathway.
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Affiliation(s)
- Andrea Carrer
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ludovica Tommasin
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Justina Šileikytė
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Francesco Ciscato
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy
| | - Andrea Urbani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Michael Forte
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Andrea Rasola
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ildikò Szabò
- Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy.,Department of Biology, University of Padova, Padova, Italy
| | - Michela Carraro
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
| | - Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, Padova, Italy. .,Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy.
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10
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Peoples JN, Ghazal N, Duong DM, Hardin KR, Manning JR, Seyfried NT, Faundez V, Kwong JQ. Loss of the mitochondrial phosphate carrier SLC25A3 induces remodeling of the cardiac mitochondrial protein acylome. Am J Physiol Cell Physiol 2021; 321:C519-C534. [PMID: 34319827 DOI: 10.1152/ajpcell.00156.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria are recognized as signaling organelles because, under stress, mitochondria can trigger various signaling pathways to coordinate the cell's response. The specific pathway(s) engaged by mitochondria in response to mitochondrial energy defects in vivo and in high-energy tissues like the heart are not fully understood. Here, we investigated cardiac pathways activated in response to mitochondrial energy dysfunction by studying mice with cardiomyocyte-specific loss of the mitochondrial phosphate carrier (SLC25A3), an established model that develops cardiomyopathy as a result of defective mitochondrial ATP synthesis. Mitochondrial energy dysfunction induced a striking pattern of acylome remodeling, with significantly increased post-translational acetylation and malonylation. Mass spectrometry-based proteomics further revealed that energy dysfunction-induced remodeling of the acetylome and malonylome preferentially impacts mitochondrial proteins. Acetylation and malonylation modified a highly interconnected interactome of mitochondrial proteins, and both modifications were present on the enzyme isocitrate dehydrogenase 2 (IDH2). Intriguingly, IDH2 activity was enhanced in SLC25A3-deleted mitochondria, and further study of IDH2 sites targeted by both acetylation and malonylation revealed that these modifications can have site-specific and distinct functional effects. Finally, we uncovered a novel crosstalk between the two modifications, whereby mitochondrial energy dysfunction-induced acetylation of sirtuin 5 (SIRT5), inhibited its function. Because SIRT5 is a mitochondrial deacylase with demalonylase activity, this finding suggests that acetylation can modulate the malonylome. Together, our results position acylations as an arm of the mitochondrial response to energy dysfunction and suggest a mechanism by which focal disruption to the energy production machinery can have an expanded impact on global mitochondrial function.
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Affiliation(s)
- Jessica N Peoples
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Nasab Ghazal
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Duc M Duong
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States
| | - Katherine R Hardin
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, United States
| | - Janet R Manning
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States
| | - Victor Faundez
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Jennifer Q Kwong
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, United States.,Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
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11
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Morciano G, Naumova N, Koprowski P, Valente S, Sardão VA, Potes Y, Rimessi A, Wieckowski MR, Oliveira PJ. The mitochondrial permeability transition pore: an evolving concept critical for cell life and death. Biol Rev Camb Philos Soc 2021; 96:2489-2521. [PMID: 34155777 DOI: 10.1111/brv.12764] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 02/06/2023]
Abstract
In this review, we summarize current knowledge of perhaps one of the most intriguing phenomena in cell biology: the mitochondrial permeability transition pore (mPTP). This phenomenon, which was initially observed as a sudden loss of inner mitochondrial membrane impermeability caused by excessive calcium, has been studied for almost 50 years, and still no definitive answer has been provided regarding its mechanisms. From its initial consideration as an in vitro artifact to the current notion that the mPTP is a phenomenon with physiological and pathological implications, a long road has been travelled. We here summarize the role of mitochondria in cytosolic calcium control and the evolving concepts regarding the mitochondrial permeability transition (mPT) and the mPTP. We show how the evolving mPTP models and mechanisms, which involve many proposed mitochondrial protein components, have arisen from methodological advances and more complex biological models. We describe how scientific progress and methodological advances have allowed milestone discoveries on mPTP regulation and composition and its recognition as a valid target for drug development and a critical component of mitochondrial biology.
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Affiliation(s)
- Giampaolo Morciano
- Maria Cecilia Hospital, GVM Care & Research, Via Corriera 1, Cotignola, Ravenna, 48033, Italy.,Department of Medical Sciences, Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Via Fossato di Mortara 70, Ferrara, 44121, Italy
| | - Natalia Naumova
- Department of Cardiac Thoracic and Vascular Sciences and Public Health, University of Padua Medical School, Via Giustiniani 2, Padova, 35128, Italy
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, Warsaw, 02-093, Poland
| | - Sara Valente
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, UC Biotech, Biocant Park, Cantanhede, 3060-197, Portugal
| | - Vilma A Sardão
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, UC Biotech, Biocant Park, Cantanhede, 3060-197, Portugal
| | - Yaiza Potes
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, Warsaw, 02-093, Poland
| | - Alessandro Rimessi
- Department of Medical Sciences, Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Via Fossato di Mortara 70, Ferrara, 44121, Italy
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, Warsaw, 02-093, Poland
| | - Paulo J Oliveira
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, UC Biotech, Biocant Park, Cantanhede, 3060-197, Portugal
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12
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Suzuki T, Terada N, Higashiyama S, Kametani K, Shirai Y, Honda M, Kai T, Li W, Tabuchi K. Non-microtubule tubulin-based backbone and subordinate components of postsynaptic density lattices. Life Sci Alliance 2021; 4:4/7/e202000945. [PMID: 34006534 PMCID: PMC8326785 DOI: 10.26508/lsa.202000945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 12/28/2022] Open
Abstract
This study proposes a postsynaptic density (PSD) lattice model comprising a non-microtubule tubulin-based backbone structure and its associated proteins, including various PSD scaffold/adaptor proteins and other PSD proteins. A purification protocol was developed to identify and analyze the component proteins of a postsynaptic density (PSD) lattice, a core structure of the PSD of excitatory synapses in the central nervous system. “Enriched”- and “lean”-type PSD lattices were purified by synaptic plasma membrane treatment to identify the protein components by comprehensive shotgun mass spectrometry and group them into minimum essential cytoskeleton (MEC) and non-MEC components. Tubulin was found to be a major component of the MEC, with non-microtubule tubulin widely distributed on the purified PSD lattice. The presence of tubulin in and around PSDs was verified by post-embedding immunogold labeling EM of cerebral cortex. Non-MEC proteins included various typical scaffold/adaptor PSD proteins and other class PSD proteins. Thus, this study provides a new PSD lattice model consisting of non-microtubule tubulin-based backbone and various non-MEC proteins. Our findings suggest that tubulin is a key component constructing the backbone and that the associated components are essential for the versatile functions of the PSD.
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Affiliation(s)
- Tatsuo Suzuki
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan
| | - Nobuo Terada
- Health Science Division, Department of Medical Sciences, Graduate School of Medicine, Science and Technology, Shinshu University, Matsumoto, Nagano, Japan
| | - Shigeki Higashiyama
- Department of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, To-on, Ehime, Japan
| | - Kiyokazu Kametani
- Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Yoshinori Shirai
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan
| | - Mamoru Honda
- Bioscience Group, Center for Precision Medicine Supports, Pharmaceuticals and Life Sciences Division, Shimadzu Techno-Research, INC, Kyoto, Japan
| | - Tsutomu Kai
- Bioscience Group, Center for Precision Medicine Supports, Pharmaceuticals and Life Sciences Division, Shimadzu Techno-Research, INC, Kyoto, Japan
| | - Weidong Li
- Bio-X Institutes, Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai, China.,Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research Shinshu University, Matsumoto, Japan
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan.,Department of Biological Sciences for Intractable Neurological Diseases, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research Shinshu University, Matsumoto, Japan
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13
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Docampo R, Vercesi AE, Huang G, Lander N, Chiurillo MA, Bertolini M. Mitochondrial Ca 2+ homeostasis in trypanosomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:261-289. [PMID: 34253297 PMCID: PMC10424509 DOI: 10.1016/bs.ircmb.2021.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mitochondrial calcium ion (Ca2+) uptake is important for buffering cytosolic Ca2+ levels, for regulating cell bioenergetics, and for cell death and autophagy. Ca2+ uptake is mediated by a mitochondrial Ca2+ uniporter (MCU) and the discovery of this channel in trypanosomes has been critical for the identification of the molecular nature of the channel in all eukaryotes. However, the trypanosome uniporter, which has been studied in detail in Trypanosoma cruzi, the agent of Chagas disease, and T. brucei, the agent of human and animal African trypanosomiasis, has lineage-specific adaptations which include the lack of some homologues to mammalian subunits, and the presence of unique subunits. Here, we review newly emerging insights into the role of mitochondrial Ca2+ homeostasis in trypanosomes, the composition of the uniporter, its functional characterization, and its role in general physiology.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States.
| | - Anibal E Vercesi
- Departamento de Patologia Clinica, Universidade Estadual de Campinas, São Paulo, Brazil
| | - Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Noelia Lander
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Miguel A Chiurillo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Mayara Bertolini
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
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14
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Ordered Clusters of the Complete Oxidative Phosphorylation System in Cardiac Mitochondria. Int J Mol Sci 2021; 22:ijms22031462. [PMID: 33540542 PMCID: PMC7867189 DOI: 10.3390/ijms22031462] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/26/2021] [Accepted: 01/30/2021] [Indexed: 01/10/2023] Open
Abstract
The existence of a complete oxidative phosphorylation system (OXPHOS) supercomplex including both electron transport system and ATP synthases has long been assumed based on functional evidence. However, no structural confirmation of the docking between ATP synthase and proton pumps has been obtained. In this study, cryo-electron tomography was used to reveal the supramolecular architecture of the rat heart mitochondria cristae during ATP synthesis. Respirasome and ATP synthase structure in situ were determined using subtomogram averaging. The obtained reconstructions of the inner mitochondrial membrane demonstrated that rows of respiratory chain supercomplexes can dock with rows of ATP synthases forming oligomeric ordered clusters. These ordered clusters indicate a new type of OXPHOS structural organization. It should ensure the quickness, efficiency, and damage resistance of OXPHOS, providing a direct proton transfer from pumps to ATP synthase along the lateral pH gradient without energy dissipation.
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15
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Zhang H, Alder NN, Wang W, Szeto H, Marcinek DJ, Rabinovitch PS. Reduction of elevated proton leak rejuvenates mitochondria in the aged cardiomyocyte. eLife 2020; 9:e60827. [PMID: 33319746 PMCID: PMC7738186 DOI: 10.7554/elife.60827] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022] Open
Abstract
Aging-associated diseases, including cardiac dysfunction, are increasingly common in the population. However, the mechanisms of physiologic aging in general, and cardiac aging in particular, remain poorly understood. Age-related heart impairment is lacking a clinically effective treatment. Using the model of naturally aging mice and rats, we show direct evidence of increased proton leak in the aged heart mitochondria. Moreover, our data suggested ANT1 as the most likely site of mediating increased mitochondrial proton permeability in old cardiomyocytes. Most importantly, the tetra-peptide SS-31 prevents age-related excess proton entry, decreases the mitochondrial flash activity and mitochondrial permeability transition pore opening, rejuvenates mitochondrial function by direct association with ANT1 and the mitochondrial ATP synthasome, and leads to substantial reversal of diastolic dysfunction. Our results uncover the excessive proton leak as a novel mechanism of age-related cardiac dysfunction and elucidate how SS-31 can reverse this clinically important complication of cardiac aging.
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Affiliation(s)
- Huiliang Zhang
- Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
| | - Nathan N Alder
- Department of Molecular and Cell Biology, University of ConnecticutStorrsUnited States
| | - Wang Wang
- Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine, University of WashingtonSeattleUnited States
| | - Hazel Szeto
- Social Profit Network Research Lab, Alexandria LaunchLabsNew YorkUnited States
| | - David J Marcinek
- Department of Radiology, University of WashingtonSeattleUnited States
| | - Peter S Rabinovitch
- Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
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16
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Mitochondrial respiratory supercomplexes in mammalian cells: structural versus functional role. J Mol Med (Berl) 2020; 99:57-73. [PMID: 33201259 DOI: 10.1007/s00109-020-02004-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/06/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023]
Abstract
Mitochondria are recognized as the main source of ATP to meet the energy demands of the cell. ATP production occurs by oxidative phosphorylation when electrons are transported through the electron transport chain (ETC) complexes and develop the proton motive force across the inner mitochondrial membrane that is used for ATP synthesis. Studies since the 1960s have been concentrated on the two models of structural organization of ETC complexes known as "solid-state" and "fluid-state" models. However, advanced new techniques such as blue-native gel electrophoresis, mass spectroscopy, and cryogenic electron microscopy for analysis of macromolecular protein complexes provided new data in favor of the solid-state model. According to this model, individual ETC complexes are assembled into macromolecular structures known as respiratory supercomplexes (SCs). A large number of studies over the last 20 years proposed the potential role of SCs to facilitate substrate channeling, maintain the integrity of individual ETC complexes, reduce electron leakage and production of reactive oxygen species, and prevent excessive and random aggregation of proteins in the inner mitochondrial membrane. However, many other studies have challenged the proposed functional role of SCs. Recently, a third model known as the "plasticity" model was proposed that partly reconciles both "solid-state" and "fluid-state" models. According to the "plasticity" model, respiratory SCs can co-exist with the individual ETC complexes. To date, the physiological role of SCs remains unknown, although several studies using tissue samples of patients or animal/cell models of human diseases revealed an associative link between functional changes and the disintegration of SC assembly. This review summarizes and discusses previous studies on the mechanisms and regulation of SC assembly under physiological and pathological conditions.
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17
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Licznerski P, Park HA, Rolyan H, Chen R, Mnatsakanyan N, Miranda P, Graham M, Wu J, Cruz-Reyes N, Mehta N, Sohail S, Salcedo J, Song E, Effman C, Effman S, Brandao L, Xu GN, Braker A, Gribkoff VK, Levy RJ, Jonas EA. ATP Synthase c-Subunit Leak Causes Aberrant Cellular Metabolism in Fragile X Syndrome. Cell 2020; 182:1170-1185.e9. [PMID: 32795412 DOI: 10.1016/j.cell.2020.07.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/04/2020] [Accepted: 07/10/2020] [Indexed: 12/26/2022]
Abstract
Loss of the gene (Fmr1) encoding Fragile X mental retardation protein (FMRP) causes increased mRNA translation and aberrant synaptic development. We find neurons of the Fmr1-/y mouse have a mitochondrial inner membrane leak contributing to a "leak metabolism." In human Fragile X syndrome (FXS) fibroblasts and in Fmr1-/y mouse neurons, closure of the ATP synthase leak channel by mild depletion of its c-subunit or pharmacological inhibition normalizes stimulus-induced and constitutive mRNA translation rate, decreases lactate and key glycolytic and tricarboxylic acid (TCA) cycle enzyme levels, and triggers synapse maturation. FMRP regulates leak closure in wild-type (WT), but not FX synapses, by stimulus-dependent ATP synthase β subunit translation; this increases the ratio of ATP synthase enzyme to its c-subunit, enhancing ATP production efficiency and synaptic growth. In contrast, in FXS, inability to close developmental c-subunit leak prevents stimulus-dependent synaptic maturation. Therefore, ATP synthase c-subunit leak closure encourages development and attenuates autistic behaviors.
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Affiliation(s)
- Pawel Licznerski
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Han-A Park
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Human Nutrition and Hospitality Management, College of Human Environmental Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Harshvardhan Rolyan
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Rongmin Chen
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Nelli Mnatsakanyan
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Paige Miranda
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Morven Graham
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jing Wu
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | | | - Nikita Mehta
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Sana Sohail
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Jorge Salcedo
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Erin Song
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | | | - Samuel Effman
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Lucas Brandao
- Department of Biology, Clark University, Worcester, MA 01610, USA
| | - Gulan N Xu
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Amber Braker
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Valentin K Gribkoff
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Richard J Levy
- Department of Anesthesiology, Columbia University Medical Center, New York, NY 10032, USA
| | - Elizabeth A Jonas
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06511, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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18
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Zhang Y, Fernie AR. On the Detection and Functional Significance of the Protein-Protein Interactions of Mitochondrial Transport Proteins. Biomolecules 2020; 10:E1107. [PMID: 32722450 PMCID: PMC7464641 DOI: 10.3390/biom10081107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/23/2022] Open
Abstract
Protein-protein assemblies are highly prevalent in all living cells. Considerable evidence has recently accumulated suggesting that particularly transient association/dissociation of proteins represent an important means of regulation of metabolism. This is true not only in the cytosol and organelle matrices, but also at membrane surfaces where, for example, receptor complexes, as well as those of key metabolic pathways, are common. Transporters also frequently come up in lists of interacting proteins, for example, binding proteins that catalyze the production of their substrates or that act as relays within signal transduction cascades. In this review, we provide an update of technologies that are used in the study of such interactions with mitochondrial transport proteins, highlighting the difficulties that arise in their use for membrane proteins and discussing our current understanding of the biological function of such interactions.
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Affiliation(s)
- Youjun Zhang
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Alisdair R. Fernie
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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19
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A Comparative Study of the Action of Protonophore Uncouplers and Decoupling Agents as Inducers of Free Respiration in Mitochondria in States 3 and 4: Theoretical and Experimental Approaches. Cell Biochem Biophys 2020; 78:203-216. [PMID: 32367259 DOI: 10.1007/s12013-020-00914-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/17/2020] [Indexed: 02/07/2023]
Abstract
Theoretical and experimental studies have revealed that that in the liver mitochondria an increase in the rate of free respiration in state 3 induced by protonophore uncouplers 2,4-dinitrophenol and сarbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone is equal to or slightly greater than the increase in respiration rate in state 4 induced by these uncouplers. In contrast to these protonophore uncouplers, the decoupler α,ω-tetradecanedioic acid, increasing the rate of respiration in state 4, does not significantly affect the rate of free respiration in state 3. We have proposed quantitative indicators that allow determining the constituent part of the rate of respiration in state 4, associated with the decoupling effect of the uncoupler. Using the example of palmitic acid, we have found out the fundamental possibility of the simultaneous functioning of uncouplers by two mechanisms: as protonophores and as decouplers. The data obtained contradict the delocalized version of Mitchell's chemiosmotic theory, but are in complete agreement with its local version. It can be assumed that the F0F1-ATP synthase and nearby respiratory chain complexes form a local zone of coupled respiration and oxidative ATP synthesis (zones of oxidative phosphorylation). The uncoupler-induced stimulation of mitochondrial free respiration of mitochondria in state 3 is mainly due to the return of protons to the matrix in local zones, where the generation of a proton motive force (Δр) by respiratory chain complexes is associated with various transport processes, but not with ATP synthesis (zones of protonophore uncoupling). In contrast, respiratory stimulation in state 4 by decouplers is realized in local zones of oxidative phosphorylation by switching the respiratory chain complexes to the idle mode of operation in the absence of ATP synthesis.
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20
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Huang G, Docampo R. The Mitochondrial Calcium Uniporter Interacts with Subunit c of the ATP Synthase of Trypanosomes and Humans. mBio 2020; 11:e00268-20. [PMID: 32184243 PMCID: PMC7078472 DOI: 10.1128/mbio.00268-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 02/12/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial Ca2+ transport mediated by the uniporter complex (MCUC) plays a key role in the regulation of cell bioenergetics in both trypanosomes and mammals. Here we report that Trypanosoma brucei MCU (TbMCU) subunits interact with subunit c of the mitochondrial ATP synthase (ATPc), as determined by coimmunoprecipitation and split-ubiquitin membrane-based yeast two-hybrid (MYTH) assays. Mutagenesis analysis in combination with MYTH assays suggested that transmembrane helices (TMHs) are determinants of this specific interaction. In situ tagging, followed by immunoprecipitation and immunofluorescence microscopy, revealed that T. brucei ATPc (TbATPc) coimmunoprecipitates with TbMCUC subunits and colocalizes with them to the mitochondria. Blue native PAGE and immunodetection analyses indicated that the TbMCUC is present together with the ATP synthase in a large protein complex with a molecular weight of approximately 900 kDa. Ablation of the TbMCUC subunits by RNA interference (RNAi) significantly increased the AMP/ATP ratio, revealing the downregulation of ATP production in the cells. Interestingly, the direct physical MCU-ATPc interaction is conserved in Trypanosoma cruzi and human cells. Specific interaction between human MCU (HsMCU) and human ATPc (HsATPc) was confirmed in vitro by mutagenesis and MYTH assays and in vivo by coimmunoprecipitation. In summary, our study has identified that MCU complex physically interacts with mitochondrial ATP synthase, possibly forming an MCUC-ATP megacomplex that couples ADP and Pi transport with ATP synthesis, a process that is stimulated by Ca2+ in trypanosomes and human cells.IMPORTANCE The mitochondrial calcium uniporter (MCU) is essential for the regulation of oxidative phosphorylation in mammalian cells, and we have shown that in Trypanosoma brucei, the etiologic agent of sleeping sickness, this channel is essential for its survival and infectivity. Here we reveal that that Trypanosoma brucei MCU subunits interact with subunit c of the mitochondrial ATP synthase (ATPc). Interestingly, the direct physical MCU-ATPc interaction is conserved in T. cruzi and human cells.
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Affiliation(s)
- Guozhong Huang
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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21
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Mitochondrial morphology provides a mechanism for energy buffering at synapses. Sci Rep 2019; 9:18306. [PMID: 31797946 PMCID: PMC6893035 DOI: 10.1038/s41598-019-54159-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/24/2019] [Indexed: 01/27/2023] Open
Abstract
Mitochondria as the main energy suppliers of eukaryotic cells are highly dynamic organelles that fuse, divide and are transported along the cytoskeleton to ensure cellular energy homeostasis. While these processes are well established, substantial evidence indicates that the internal structure is also highly variable in dependence on metabolic conditions. However, a quantitative mechanistic understanding of how mitochondrial morphology affects energetic states is still elusive. To address this question, we here present an agent-based multiscale model that integrates three-dimensional morphologies from electron microscopy tomography with the molecular dynamics of the main ATP producing components. We apply our modeling approach to mitochondria at the synapse which is the largest energy consumer within the brain. Interestingly, comparing the spatiotemporal simulations with a corresponding space-independent approach, we find minor spatial effects when the system relaxes toward equilibrium but a qualitative difference in fluctuating environments. These results suggest that internal mitochondrial morphology is not only optimized for ATP production but also provides a mechanism for energy buffering and may represent a mechanism for cellular robustness.
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22
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Nath S. Consolidation of Nath's torsional mechanism of ATP synthesis and two-ion theory of energy coupling in oxidative phosphorylation and photophosphorylation. Biophys Chem 2019; 257:106279. [PMID: 31757522 DOI: 10.1016/j.bpc.2019.106279] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/08/2019] [Indexed: 01/09/2023]
Abstract
In a recent publication, Manoj raises criticisms against consensus views on the ATP synthase. The radical statements and assertions are shown to contradict a vast body of available knowledge that includes i) pioneering single-molecule biochemical and biophysical studies from the respected experimental groups of Kinosita, Yoshida, Noji, Börsch, Dunn, Gräber, Frasch, and Dimroth etc., ii) state-of-the-art X-ray and EM/cryo-EM structural information garnered over the decades by the expert groups of Leslie-Walker, Kühlbrandt, Mueller, Meier, Rubinstein, Sazanov, Duncan, and Pedersen on ATP synthase, iii) the pioneering energy-based computer simulations of Warshel, and iv) the novel theoretical and experimental works of Nath. Valid objections against Mitchell's chemiosmotic theory and Boyer's binding change mechanism put forth by Manoj have been addressed satisfactorily by Nath's torsional mechanism of ATP synthesis and two-ion theory of energy coupling and published 10 to 20 years ago, but these papers are not cited by him. This communication shows conclusively and in great detail that none of his objections apply to Nath's mechanism/theory. Nath's theory is further consolidated based on its previous predictive record, its consistency with biochemical evidence, its unified nature, its application to other related energy transductions and to disease, and finally its ability to guide the design of new experiments. Some constructive suggestions for high-resolution structural experiments that have the power to delve into the heart of the matter and throw unprecedented light on the nature of coupled ion translocation in the membrane-bound FO portion of F1FO-ATP synthase are made.
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Affiliation(s)
- Sunil Nath
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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23
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Milenkovic VM, Slim D, Bader S, Koch V, Heinl ES, Alvarez-Carbonell D, Nothdurfter C, Rupprecht R, Wetzel CH. CRISPR-Cas9 Mediated TSPO Gene Knockout alters Respiration and Cellular Metabolism in Human Primary Microglia Cells. Int J Mol Sci 2019; 20:ijms20133359. [PMID: 31323920 PMCID: PMC6651328 DOI: 10.3390/ijms20133359] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/04/2019] [Accepted: 07/07/2019] [Indexed: 02/06/2023] Open
Abstract
The 18 kDa translocator protein (TSPO) is an evolutionary conserved cholesterol binding protein localized in the outer mitochondrial membrane. It has been implicated in the regulation of various cellular processes including oxidative stress, proliferation, apoptosis, and steroid hormone biosynthesis. Since the expression of TSPO in activated microglia is upregulated in various neuroinflammatory and neurodegenerative disorders, we set out to examine the role of TSPO in an immortalized human microglia C20 cell line. To this end, we performed a dual approach and used (i) lentiviral shRNA silencing to reduce TSPO expression, and (ii) the CRISPR/Cas9 technology to generate complete TSPO knockout microglia cell lines. Functional characterization of control and TSPO knockdown as well as knockout cells, revealed only low de novo steroidogenesis in C20 cells, which was not dependent on the level of TSPO expression or influenced by the treatment with TSPO-specific ligands. In contrast to TSPO knockdown C20 cells, which did not show altered mitochondrial function, the TSPO deficient knockout cells displayed a significantly decreased mitochondrial membrane potential and cytosolic Ca2+ levels, as well as reduced respiratory function. Performing the rescue experiment by lentiviral overexpression of TSPO in knockout cells, increased oxygen consumption and restored respiratory function. Our study provides further evidence for a significant role of TSPO in cellular and mitochondrial metabolism and demonstrates that different phenotypes of mitochondrial function are dependent on the level of TSPO expression.
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Affiliation(s)
- Vladimir M Milenkovic
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Dounia Slim
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Stefanie Bader
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Victoria Koch
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Elena-Sofia Heinl
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - David Alvarez-Carbonell
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Christian H Wetzel
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany.
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24
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Chen R, Park HA, Mnatsakanyan N, Niu Y, Licznerski P, Wu J, Miranda P, Graham M, Tang J, Boon AJW, Cossu G, Mandemakers W, Bonifati V, Smith PJS, Alavian KN, Jonas EA. Parkinson's disease protein DJ-1 regulates ATP synthase protein components to increase neuronal process outgrowth. Cell Death Dis 2019; 10:469. [PMID: 31197129 PMCID: PMC6565618 DOI: 10.1038/s41419-019-1679-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/10/2019] [Accepted: 05/19/2019] [Indexed: 12/17/2022]
Abstract
Familial Parkinson’s disease (PD) protein DJ-1 mutations are linked to early onset PD. We have found that DJ-1 binds directly to the F1FO ATP synthase β subunit. DJ-1’s interaction with the β subunit decreased mitochondrial uncoupling and enhanced ATP production efficiency while in contrast mutations in DJ-1 or DJ-1 knockout increased mitochondrial uncoupling, and depolarized neuronal mitochondria. In mesencephalic DJ-1 KO cultures, there was a progressive loss of neuronal process extension. This was ameliorated by a pharmacological reagent, dexpramipexole, that binds to ATP synthase, closing a mitochondrial inner membrane leak and enhancing ATP synthase efficiency. ATP synthase c-subunit can form an uncoupling channel; we measured, therefore, ATP synthase F1 (β subunit) and c-subunit protein levels. We found that ATP synthase β subunit protein level in the DJ-1 KO neurons was approximately half that found in their wild-type counterparts, comprising a severe defect in ATP synthase stoichiometry and unmasking c-subunit. We suggest that DJ-1 enhances dopaminergic cell metabolism and growth by its regulation of ATP synthase protein components.
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Affiliation(s)
- Rongmin Chen
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Han-A Park
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA.,Department of Human Nutrition and Hospitality Management, University of Alabama, Tuscaloosa, AL, USA
| | - Nelli Mnatsakanyan
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Yulong Niu
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Pawel Licznerski
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Jing Wu
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Paige Miranda
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Morven Graham
- Department of Cell Biology, Yale University, New Haven, CT, USA
| | - Jack Tang
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA
| | - Agnita J W Boon
- Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
| | - Giovanni Cossu
- Neurology Service and Stroke Unit, Brotzu General Hospital, Cagliari, Italy
| | - Wim Mandemakers
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Vincenzo Bonifati
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Peter J S Smith
- Institute of Life Sciences, University of Southampton, Southampton, England.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Kambiz N Alavian
- Marine Biological Laboratory, Woods Hole, MA, USA.,Division of Brain Sciences, Department of Medicine, Imperial College, London, UK
| | - Elizabeth A Jonas
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, CT, USA. .,Marine Biological Laboratory, Woods Hole, MA, USA. .,Department of Neuroscience, Yale University, New Haven, CT, USA.
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25
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Galber C, Valente G, von Stockum S, Giorgio V. Purification of Functional F-ATP Synthase from Blue Native PAGE. Methods Mol Biol 2019; 1925:233-243. [PMID: 30674031 DOI: 10.1007/978-1-4939-9018-4_20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the presence of Ca2+, F-ATP synthase preparations eluted from Blue Native gels generate electrophysiological currents that are typical of an inner mitochondrial membrane mega-channel, the permeability transition pore. Here we describe an experimental protocol for purification of F-ATP synthase that allows to maintain the enzyme assembly and activity that are essential for catalysis and channel formation.
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Affiliation(s)
- Chiara Galber
- Neuroscience Institute and Department of Biomedical Sciences, CNR and University of Padua, Padua, Italy
| | - Giulia Valente
- Neuroscience Institute and Department of Biomedical Sciences, CNR and University of Padua, Padua, Italy
| | - Sophia von Stockum
- Department of Biology, University of Padua, Padua, Italy
- Fondazione Ospedale San Camillo, IRCCS, Venezia, Italy
| | - Valentina Giorgio
- Neuroscience Institute and Department of Biomedical Sciences, CNR and University of Padua, Padua, Italy.
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26
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Briston T, Selwood DL, Szabadkai G, Duchen MR. Mitochondrial Permeability Transition: A Molecular Lesion with Multiple Drug Targets. Trends Pharmacol Sci 2018; 40:50-70. [PMID: 30527591 DOI: 10.1016/j.tips.2018.11.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 12/13/2022]
Abstract
Mitochondrial permeability transition, as the consequence of opening of a mitochondrial permeability transition pore (mPTP), is a cellular catastrophe. Initiating bioenergetic collapse and cell death, it has been implicated in the pathophysiology of major human diseases, including neuromuscular diseases of childhood, ischaemia-reperfusion injury, and age-related neurodegenerative disease. Opening of the mPTP represents a major therapeutic target, as it can be mitigated by a number of compounds. However, clinical studies have so far been disappointing. We therefore address the prospects and challenges faced in translating in vitro findings to clinical benefit. We review the role of mPTP opening in disease, discuss recent findings defining the putative structure of the mPTP, and explore strategies to identify novel, clinically useful mPTP inhibitors, highlighting key considerations in the drug discovery process.
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Affiliation(s)
- Thomas Briston
- Neurology Innovation Centre, Hatfield Research Laboratories, Eisai Ltd., Hatfield, UK.
| | - David L Selwood
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, UK; Department of Biomedical Sciences, University of Padua, Padua, Italy; The Francis Crick Institute, London, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, UK
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27
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Intracellular Energy-Transfer Networks and High-Resolution Respirometry: A Convenient Approach for Studying Their Function. Int J Mol Sci 2018; 19:ijms19102933. [PMID: 30261663 PMCID: PMC6213097 DOI: 10.3390/ijms19102933] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/19/2018] [Accepted: 09/21/2018] [Indexed: 12/21/2022] Open
Abstract
Compartmentalization of high-energy phosphate carriers between intracellular micro-compartments is a phenomenon that ensures efficient energy use. To connect these sites, creatine kinase (CK) and adenylate kinase (AK) energy-transfer networks, which are functionally coupled to oxidative phosphorylation (OXPHOS), could serve as important regulators of cellular energy fluxes. Here, we introduce how selective permeabilization of cellular outer membrane and high-resolution respirometry can be used to study functional coupling between CK or AK pathways and OXPHOS in different cells and tissues. Using the protocols presented here the ability of creatine or adenosine monophosphate to stimulate OXPHOS through CK and AK reactions, respectively, is easily observable and quantifiable. Additionally, functional coupling between hexokinase and mitochondria can be investigated by monitoring the effect of glucose on respiration. Taken together, high-resolution respirometry in combination with permeabilization is a convenient approach for investigating energy-transfer networks in small quantities of cells and tissues in health and in pathology.
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28
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Sgarbi G, Barbato S, Costanzini A, Solaini G, Baracca A. The role of the ATPase inhibitor factor 1 (IF 1) in cancer cells adaptation to hypoxia and anoxia. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2018; 1859:99-109. [PMID: 29097244 DOI: 10.1016/j.bbabio.2017.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/19/2017] [Accepted: 10/27/2017] [Indexed: 12/23/2022]
Abstract
The physiological role of the mitochondrial ATP synthase complex is to generate ATP through oxidative phosphorylation. Indeed, the enzyme can reverse its activity and hydrolyze ATP under ischemic conditions, as shown in isolated mitochondria and in mammalian heart and liver. However, what occurs when cancer cells experience hypoxia or anoxia has not been well explored. In the present study, we investigated the bioenergetics of cancer cells under hypoxic/anoxic conditions with particular emphasis on ATP synthase, and the conditions driving it to work in reverse. In this context, we further examined the role exerted by its endogenous inhibitor factor, IF1, that it is overexpressed in cancer cells. Metabolic and bioenergetic analysis of cancer cells exposed to severe hypoxia (down to 0.1% O2) unexpectedly showed that Δψm is preserved independently of the presence of IF1 and that ATP synthase still phosphorylates ADP though at a much lower rate than in normoxia. However, when we induced an anoxia-mimicking condition by collapsing ΔμΗ+ with the FCCP uncoupler, the IF1-silenced clones only reversed the ATP synthase activity hydrolyzing ATP in order to reconstitute the electrochemical proton gradient. Notably, in cancer cells IF1 overexpression fully prevents ATP synthase hydrolytic activity activation under uncoupling conditions. Therefore, our results suggest that IF1 overexpression promotes cancer cells survival under temporary anoxic conditions by preserving cellular ATP despite mitochondria dysfunction.
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Affiliation(s)
- G Sgarbi
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy
| | - S Barbato
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy
| | - A Costanzini
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy
| | - G Solaini
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy.
| | - A Baracca
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy.
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29
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Liu F, Lössl P, Rabbitts BM, Balaban RS, Heck AJR. The interactome of intact mitochondria by cross-linking mass spectrometry provides evidence for coexisting respiratory supercomplexes. Mol Cell Proteomics 2018; 17:216-232. [PMID: 29222160 PMCID: PMC5795388 DOI: 10.1074/mcp.ra117.000470] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Indexed: 12/22/2022] Open
Abstract
Mitochondria exert an immense amount of cytophysiological functions, but the structural basis of most of these processes is still poorly understood. Here we use cross-linking mass spectrometry to probe the organization of proteins in native mouse heart mitochondria. Our approach provides the largest survey of mitochondrial protein interactions reported so far. In total, we identify 3,322 unique residue-to-residue contacts involving half of the mitochondrial proteome detected by bottom-up proteomics. The obtained mitochondrial protein interactome gives insights in the architecture and submitochondrial localization of defined protein assemblies, and reveals the mitochondrial localization of four proteins not yet included in the MitoCarta database. As one of the highlights, we show that the oxidative phosphorylation complexes I-V exist in close spatial proximity, providing direct evidence for supercomplex assembly in intact mitochondria. The specificity of these contacts is demonstrated by comparative analysis of mitochondria after high salt treatment, which disrupts the native supercomplexes and substantially changes the mitochondrial interactome.
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Affiliation(s)
- Fan Liu
- From the ‡Biomolecular Mass Spectrometry and Proteomics. Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- §Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- ¶Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Rössle-Straβe 10, 13125 Berlin, Germany
| | - Philip Lössl
- From the ‡Biomolecular Mass Spectrometry and Proteomics. Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- §Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Beverley M Rabbitts
- ‖Laboratory of Cardiac Energetics, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Robert S Balaban
- ‖Laboratory of Cardiac Energetics, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Albert J R Heck
- From the ‡Biomolecular Mass Spectrometry and Proteomics. Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands;
- §Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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30
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Boulet A, Vest KE, Maynard MK, Gammon MG, Russell AC, Mathews AT, Cole SE, Zhu X, Phillips CB, Kwong JQ, Dodani SC, Leary SC, Cobine PA. The mammalian phosphate carrier SLC25A3 is a mitochondrial copper transporter required for cytochrome c oxidase biogenesis. J Biol Chem 2017; 293:1887-1896. [PMID: 29237729 DOI: 10.1074/jbc.ra117.000265] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/09/2017] [Indexed: 01/01/2023] Open
Abstract
Copper is required for the activity of cytochrome c oxidase (COX), the terminal electron-accepting complex of the mitochondrial respiratory chain. The likely source of copper used for COX biogenesis is a labile pool found in the mitochondrial matrix. In mammals, the proteins that transport copper across the inner mitochondrial membrane remain unknown. We previously reported that the mitochondrial carrier family protein Pic2 in budding yeast is a copper importer. The closest Pic2 ortholog in mammalian cells is the mitochondrial phosphate carrier SLC25A3. Here, to investigate whether SLC25A3 also transports copper, we manipulated its expression in several murine and human cell lines. SLC25A3 knockdown or deletion consistently resulted in an isolated COX deficiency in these cells, and copper addition to the culture medium suppressed these biochemical defects. Consistent with a conserved role for SLC25A3 in copper transport, its heterologous expression in yeast complemented copper-specific defects observed upon deletion of PIC2 Additionally, assays in Lactococcus lactis and in reconstituted liposomes directly demonstrated that SLC25A3 functions as a copper transporter. Taken together, these data indicate that SLC25A3 can transport copper both in vitro and in vivo.
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Affiliation(s)
- Aren Boulet
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan 7N 5E5, Canada
| | - Katherine E Vest
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | - Margaret K Maynard
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | - Micah G Gammon
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | | | - Alexander T Mathews
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | - Shelbie E Cole
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | - Xinyu Zhu
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | - Casey B Phillips
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849
| | - Jennifer Q Kwong
- Department of Pediatrics, Emory University, Atlanta, Georgia 30322, and
| | - Sheel C Dodani
- the Department of Chemistry and Biochemistry, University of Texas at Dallas, Dallas, Texas 75080
| | - Scot C Leary
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan 7N 5E5, Canada
| | - Paul A Cobine
- the Department of Biological Sciences, Auburn University, Auburn, Alabama 36849,
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31
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Javadov S, Jang S, Parodi-Rullán R, Khuchua Z, Kuznetsov AV. Mitochondrial permeability transition in cardiac ischemia-reperfusion: whether cyclophilin D is a viable target for cardioprotection? Cell Mol Life Sci 2017; 74:2795-2813. [PMID: 28378042 PMCID: PMC5977999 DOI: 10.1007/s00018-017-2502-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/28/2017] [Accepted: 03/06/2017] [Indexed: 12/13/2022]
Abstract
Growing number of studies provide strong evidence that the mitochondrial permeability transition pore (PTP), a non-selective channel in the inner mitochondrial membrane, is involved in the pathogenesis of cardiac ischemia-reperfusion and can be targeted to attenuate reperfusion-induced damage to the myocardium. The molecular identity of the PTP remains unknown and cyclophilin D is the only protein commonly accepted as a major regulator of the PTP opening. Therefore, cyclophilin D is an attractive target for pharmacological or genetic therapies to reduce ischemia-reperfusion injury in various animal models and humans. Most animal studies demonstrated cardioprotective effects of PTP inhibition; however, a recent large clinical trial conducted by international groups demonstrated that cyclosporine A, a cyclophilin D inhibitor, failed to protect the heart in patients with myocardial infarction. These studies, among others, raise the question of whether cyclophilin D, which plays an important physiological role in the regulation of cell metabolism and mitochondrial bioenergetics, is a viable target for cardioprotection. This review discusses previous studies to provide comprehensive information on the physiological role of cyclophilin D as well as PTP opening in the cell that can be taken into consideration for the development of new PTP inhibitors.
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Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico.
| | - Sehwan Jang
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico
| | - Rebecca Parodi-Rullán
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico
| | - Zaza Khuchua
- Cincinnati Children's Research Foundation, University of Cincinnati, 240 Albert Sabin Way, Cincinnati, OH, 54229, USA
| | - Andrey V Kuznetsov
- Cardiac Surgery Research Laboratory, Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria
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32
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Cardouat G, Duparc T, Fried S, Perret B, Najib S, Martinez LO. Ectopic adenine nucleotide translocase activity controls extracellular ADP levels and regulates the F 1-ATPase-mediated HDL endocytosis pathway on hepatocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:832-841. [PMID: 28504211 DOI: 10.1016/j.bbalip.2017.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 04/22/2017] [Accepted: 05/09/2017] [Indexed: 11/26/2022]
Abstract
Ecto-F1-ATPase is a complex related to mitochondrial ATP synthase which has been identified as a plasma membrane receptor for apolipoprotein A-I (apoA-I), the major protein of high-density lipoprotein (HDL), and has been shown to contribute to HDL endocytosis in several cell types. On hepatocytes, apoA-I binding to ecto-F1-ATPase stimulates extracellular ATP hydrolysis into ADP, which subsequently activates a P2Y13-mediated HDL endocytosis pathway. Interestingly, other mitochondrial proteins have been found to be expressed at the plasma membrane of several cell types. Among these, adenine nucleotide translocase (ANT) is an ADP/ATP carrier but its role in controlling extracellular ADP levels and F1-ATPase-mediated HDL endocytosis has never been investigated. Here we confirmed the presence of ANT at the plasma membrane of human hepatocytes. We then showed that ecto-ANT activity increases or reduces extracellular ADP level, depending on the extracellular ADP/ATP ratio. Interestingly, ecto-ANT co-localized with ecto-F1-ATPase at the hepatocyte plasma membrane and pharmacological inhibition of ecto-ANT activity increased extracellular ADP level when ecto-F1-ATPase was activated by apoA-I. This increase in the bioavailability of extracellular ADP accordingly translated into an increase of HDL endocytosis on human hepatocytes. This study thus uncovered a new location and function of ANT for which activity at the cell surface of hepatocytes modulates the concentration of extracellular ADP and regulates HDL endocytosis.
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Affiliation(s)
- G Cardouat
- Institute of Metabolic and Cardiovascular diseases, I2MC, Inserm, Université de Toulouse, UMR 1048, Toulouse 31000, France
| | - T Duparc
- Institute of Metabolic and Cardiovascular diseases, I2MC, Inserm, Université de Toulouse, UMR 1048, Toulouse 31000, France
| | - S Fried
- Institute of Metabolic and Cardiovascular diseases, I2MC, Inserm, Université de Toulouse, UMR 1048, Toulouse 31000, France
| | - B Perret
- Institute of Metabolic and Cardiovascular diseases, I2MC, Inserm, Université de Toulouse, UMR 1048, Toulouse 31000, France; Service de Biochimie, Pôle biologie, Hôpital de Purpan, CHU de Toulouse, Toulouse, France
| | - S Najib
- Institute of Metabolic and Cardiovascular diseases, I2MC, Inserm, Université de Toulouse, UMR 1048, Toulouse 31000, France.
| | - L O Martinez
- Institute of Metabolic and Cardiovascular diseases, I2MC, Inserm, Université de Toulouse, UMR 1048, Toulouse 31000, France.
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33
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Lu YW, Acoba MG, Selvaraju K, Huang TC, Nirujogi RS, Sathe G, Pandey A, Claypool SM. Human adenine nucleotide translocases physically and functionally interact with respirasomes. Mol Biol Cell 2017; 28:1489-1506. [PMID: 28404750 PMCID: PMC5449148 DOI: 10.1091/mbc.e17-03-0195] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 03/30/2017] [Accepted: 04/04/2017] [Indexed: 11/11/2022] Open
Abstract
A network of interactions for human adenine nucleotide translocases, required for oxidative phosphorylation, is reported. Of particular interest is an evolutionarily conserved and functionally important association with respiratory supercomplexes, which is surprising because the respirasomes of yeast and mammals are different. Members of the adenine nucleotide translocase (ANT) family exchange ADP for ATP across the mitochondrial inner membrane, an activity that is essential for oxidative phosphorylation (OXPHOS). Mutations in or dysregulation of ANTs is associated with progressive external ophthalmoplegia, cardiomyopathy, nonsyndromic intellectual disability, apoptosis, and the Warburg effect. Binding partners of human ANTs have not been systematically identified. The absence of such information has prevented a detailed molecular understanding of the assorted ANT-associated diseases, including insight into their disparate phenotypic manifestations. To fill this void, in this study, we define the interactomes of two human ANT isoforms. Analogous to its yeast counterpart, human ANTs associate with heterologous partner proteins, including the respiratory supercomplex (RSC) and other solute carriers. The evolutionarily conserved ANT–RSC association is particularly noteworthy because the composition, and thereby organization, of RSCs in yeast and human is different. Surprisingly, absence of the major ANT isoform only modestly impairs OXPHOS in HEK293 cells, indicating that the low levels of other isoforms provide functional redundancy. In contrast, pharmacological inhibition of OXPHOS expression and function inhibits ANT-dependent ADP/ATP exchange. Thus ANTs and the OXPHOS machinery physically interact and functionally cooperate to enhance ANT transport capacity and mitochondrial respiration.
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Affiliation(s)
- Ya-Wen Lu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Michelle Grace Acoba
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Kandasamy Selvaraju
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Tai-Chung Huang
- McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185.,Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University Cancer Center, Taipei 10051, Taiwan
| | - Raja S Nirujogi
- McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Gajanan Sathe
- McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Akhilesh Pandey
- McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
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34
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Yadav KS, Miranda-Astudillo HV, Colina-Tenorio L, Bouillenne F, Degand H, Morsomme P, González-Halphen D, Boekema EJ, Cardol P. Atypical composition and structure of the mitochondrial dimeric ATP synthase from Euglena gracilis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:267-275. [DOI: 10.1016/j.bbabio.2017.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/22/2016] [Accepted: 01/10/2017] [Indexed: 11/26/2022]
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35
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Cho J, Zhang Y, Park SY, Joseph AM, Han C, Park HJ, Kalavalapalli S, Chun SK, Morgan D, Kim JS, Someya S, Mathews CE, Lee YJ, Wohlgemuth SE, Sunny NE, Lee HY, Choi CS, Shiratsuchi T, Oh SP, Terada N. Mitochondrial ATP transporter depletion protects mice against liver steatosis and insulin resistance. Nat Commun 2017; 8:14477. [PMID: 28205519 PMCID: PMC5316896 DOI: 10.1038/ncomms14477] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 01/04/2017] [Indexed: 12/31/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disorder in obese individuals. Adenine nucleotide translocase (ANT) exchanges ADP/ATP through the mitochondrial inner membrane, and Ant2 is the predominant isoform expressed in the liver. Here we demonstrate that targeted disruption of Ant2 in mouse liver enhances uncoupled respiration without damaging mitochondrial integrity and liver functions. Interestingly, liver specific Ant2 knockout mice are leaner and resistant to hepatic steatosis, obesity and insulin resistance under a lipogenic diet. Protection against fatty liver is partially recapitulated by the systemic administration of low-dose carboxyatractyloside, a specific inhibitor of ANT. Targeted manipulation of hepatic mitochondrial metabolism, particularly through inhibition of ANT, may represent an alternative approach in NAFLD and obesity treatment. Adenine nucleotide translocase (ANT) 2 promotes ADP/ATP exchange across the mitochondrial inner membrane. Cho et al. show that liver specific Ant2 deletion increases uncoupled respiration and protects mice against fatty liver and obesity-induced insulin resistance.
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Affiliation(s)
- Joonseok Cho
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Yujian Zhang
- Otsuka Maryland Medicinal Laboratories, Rockville, Maryland 20850, USA
| | - Shi-Young Park
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Anna-Maria Joseph
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Chul Han
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Hyo-Jin Park
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Srilaxmi Kalavalapalli
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Sung-Kook Chun
- Department of Surgery, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Drake Morgan
- Department of Psychiatry, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Jae-Sung Kim
- Department of Surgery, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Shinichi Someya
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Clayton E Mathews
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Young Jae Lee
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Stephanie E Wohlgemuth
- Department of Animal Sciences, University of Florida College of Medicine, Gainesville, Florida 32611, USA
| | - Nishanth E Sunny
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Hui-Young Lee
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Cheol Soo Choi
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea.,Endocrinology, Internal Medicine, Gachon University Gil Medical Center, Incheon 405-760, Korea
| | | | - S Paul Oh
- Department of Physiology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Naohiro Terada
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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Liu GJ, Middleton RJ, Kam WWY, Chin DY, Hatty CR, Chan RHY, Banati RB. Functional gains in energy and cell metabolism after TSPO gene insertion. Cell Cycle 2017; 16:436-447. [PMID: 28103132 PMCID: PMC5351937 DOI: 10.1080/15384101.2017.1281477] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Recent loss-of-function studies in tissue-specific as well as global Tspo (Translocator Protein 18 kDa) knockout mice have not confirmed its long assumed indispensability for the translocation of cholesterol across the mitochondrial inter-membrane space, a rate-limiting step in steroid biosynthesis. Instead, recent studies in global Tspo knockout mice indicate that TSPO may play a more fundamental role in cellular bioenergetics, which may include the indirect down-stream regulation of transport or metabolic functions. To examine whether overexpression of the TSPO protein alters the cellular bioenergetic profile, Jurkat cells with low to absent endogenous expression were transfected with a TSPO construct to create a stable cell line with de novo expression of exogenous TSPO protein. Expression of TSPO was confirmed by RT-qPCR, radioligand binding with [3H]PK11195 and immunocytochemistry with a TSPO antibody. We demonstrate that TSPO gene insertion causes increased transcription of genes involved in the mitochondrial electron transport chain. Furthermore, TSPO insertion increased mitochondrial ATP production as well as cell excitability, reflected in a decrease in patch clamp recorded rectified K channel currents. These functional changes were accompanied by an increase in cell proliferation and motility, which were inhibited by PK11195, a selective ligand for TSPO. We suggest that TSPO may serve a range of functions that can be viewed as downstream regulatory effects of its primary, evolutionary conserved role in cell metabolism and energy production.
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Affiliation(s)
- Guo-Jun Liu
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
| | - Ryan J Middleton
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia
| | - Winnie Wai-Ying Kam
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,c Department of Health Technology and Informatics , Hong Kong Polytechnic University , Hung Hom, Hong Kong , China
| | - David Y Chin
- d NCRIS Biologics Facility, Australian Institute for Bioengineering and Nanotechnology, University of Queensland , QLD , Australia
| | - Claire R Hatty
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
| | - Ronald H Y Chan
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
| | - Richard B Banati
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
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Seifert EL, Gál A, Acoba MG, Li Q, Anderson-Pullinger L, Golenár T, Moffat C, Sondheimer N, Claypool SM, Hajnóczky G. Natural and Induced Mitochondrial Phosphate Carrier Loss: DIFFERENTIAL DEPENDENCE OF MITOCHONDRIAL METABOLISM AND DYNAMICS AND CELL SURVIVAL ON THE EXTENT OF DEPLETION. J Biol Chem 2016; 291:26126-26137. [PMID: 27780865 DOI: 10.1074/jbc.m116.744714] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/06/2016] [Indexed: 12/22/2022] Open
Abstract
The relevance of mitochondrial phosphate carrier (PiC), encoded by SLC25A3, in bioenergetics is well accepted. However, little is known about the mechanisms mediating the cellular impairments induced by pathological SLC25A3 variants. To this end, we investigated the pathogenicity of a novel compound heterozygous mutation in SLC25A3 First, each variant was modeled in yeast, revealing that substituting GSSAS for QIP within the fifth matrix loop is incompatible with survival on non-fermentable substrate, whereas the L200W variant is functionally neutral. Next, using skin fibroblasts from an individual expressing these variants and HeLa cells with varying degrees of PiC depletion, PiC loss of ∼60% was still compatible with uncompromised maximal oxidative phosphorylation (oxphos), whereas lower maximal oxphos was evident at ∼85% PiC depletion. Furthermore, intact mutant fibroblasts displayed suppressed mitochondrial bioenergetics consistent with a lower substrate availability rather than phosphate limitation. This was accompanied by slowed proliferation in glucose-replete medium; however, proliferation ceased when only mitochondrial substrate was provided. Both mutant fibroblasts and HeLa cells with 60% PiC loss showed a less interconnected mitochondrial network and a mitochondrial fusion defect that is not explained by altered abundance of OPA1 or MFN1/2 or relative amount of different OPA1 forms. Altogether these results indicate that PiC depletion may need to be profound (>85%) to substantially affect maximal oxphos and that pathogenesis associated with PiC depletion or loss of function may be independent of phosphate limitation when ATP requirements are not high.
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Affiliation(s)
- Erin L Seifert
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107,
| | - Aniko Gál
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Michelle G Acoba
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - Qipei Li
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Lauren Anderson-Pullinger
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Tunde Golenár
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Cynthia Moffat
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Neal Sondheimer
- Division of Clinical and Metabolic Genetics, Hospital for Sick Children and Department of Paediatrics, University of Toronto, Toronto, Ontario M5G 1X8, Canada
| | - Steven M Claypool
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - György Hajnóczky
- From the MitoCare Center for Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107,
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38
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Nath S. The thermodynamic efficiency of ATP synthesis in oxidative phosphorylation. Biophys Chem 2016; 219:69-74. [PMID: 27770651 DOI: 10.1016/j.bpc.2016.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 10/12/2016] [Accepted: 10/12/2016] [Indexed: 12/20/2022]
Abstract
As the chief energy source of eukaryotic cells, it is important to determine the thermodynamic efficiency of ATP synthesis in oxidative phosphorylation (OX PHOS). Previous estimates of the thermodynamic efficiency of this vital process have ranged from Lehninger's original back-of-the-envelope calculation of 38% to the often quoted value of 55-60% in current textbooks of biochemistry, to high values of 90% from recent information theoretic considerations, and reports of realizations of close to ideal 100% efficiencies by single molecule experiments. Hence this problem has been reinvestigated from first principles. The overall thermodynamic efficiency of ATP synthesis in the mitochondrial energy transduction OX PHOS process has been found to lie between 40 and 41% from four different approaches based on a) estimation using structural and biochemical data, b) fundamental nonequilibrium thermodynamic analysis, c) novel insights arising from Nath's torsional mechanism of energy transduction and ATP synthesis, and d) the overall balance of cellular energetics. The torsional mechanism also offers an explanation for the observation of a thermodynamic efficiency approaching 100% in some experiments. Applications of the unique, molecular machine mode of functioning of F1FO-ATP synthase involving direct inter-conversion of chemical and mechanical energies in the design and fabrication of novel, man-made mechanochemical devices have been envisaged, and some new ways to exorcise Maxwell's demon have been proposed. It is hoped that analysis of the fundamental problem of energy transduction in OX PHOS from a fresh perspective will catalyze new avenues of research in this interdisciplinary field.
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Affiliation(s)
- Sunil Nath
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India.
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39
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Biasutto L, Azzolini M, Szabò I, Zoratti M. The mitochondrial permeability transition pore in AD 2016: An update. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:2515-30. [PMID: 26902508 DOI: 10.1016/j.bbamcr.2016.02.012] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
Abstract
Over the past 30years the mitochondrial permeability transition - the permeabilization of the inner mitochondrial membrane due to the opening of a wide pore - has progressed from being considered a curious artifact induced in isolated mitochondria by Ca(2+) and phosphate to a key cell-death-inducing process in several major pathologies. Its relevance is by now universally acknowledged and a pharmacology targeting the phenomenon is being developed. The molecular nature of the pore remains to this day uncertain, but progress has recently been made with the identification of the FOF1 ATP synthase as the probable proteic substrate. Researchers sharing this conviction are however divided into two camps: these believing that only the ATP synthase dimers or oligomers can form the pore, presumably in the contact region between monomers, and those who consider that the ring-forming c subunits in the FO sector actually constitute the walls of the pore. The latest development is the emergence of a new candidate: Spastic Paraplegia 7 (SPG7), a mitochondrial AAA-type membrane protease which forms a 6-stave barrel. This review summarizes recent developments of research on the pathophysiological relevance and on the molecular nature of the mitochondrial permeability transition pore. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Lucia Biasutto
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy
| | - Michele Azzolini
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy
| | - Ildikò Szabò
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biology, Viale G. Colombo 3, 35121 Padova, Italy
| | - Mario Zoratti
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy.
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Ying Y, Padanilam BJ. Regulation of necrotic cell death: p53, PARP1 and cyclophilin D-overlapping pathways of regulated necrosis? Cell Mol Life Sci 2016; 73:2309-24. [PMID: 27048819 PMCID: PMC5490387 DOI: 10.1007/s00018-016-2202-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 03/18/2016] [Indexed: 12/15/2022]
Abstract
In contrast to apoptosis and autophagy, necrotic cell death was considered to be a random, passive cell death without definable mediators. However, this dogma has been challenged by recent developments suggesting that necrotic cell death can also be a regulated process. Regulated necrosis includes multiple cell death modalities such as necroptosis, parthanatos, ferroptosis, pyroptosis, and mitochondrial permeability transition pore (MPTP)-mediated necrosis. Several distinctive executive molecules, particularly residing on the mitochondrial inner and outer membrane, amalgamating to form the MPTP have been defined. The c-subunit of the F1F0ATP synthase on the inner membrane and Bax/Bak on the outer membrane are considered to be the long sought components that form the MPTP. Opening of the MPTP results in loss of mitochondrial inner membrane potential, disruption of ATP production, increased ROS production, organelle swelling, mitochondrial dysfunction and consequent necrosis. Cyclophilin D, along with adenine nucleotide translocator and the phosphate carrier are considered to be important regulators involved in the opening of MPTP. Increased production of ROS can further trigger other necrotic pathways mediated through molecules such as PARP1, leading to irreversible cell damage. This review examines the roles of PARP1 and cyclophilin D in necrotic cell death. The hierarchical role of p53 in regulation and integration of key components of signaling pathway to elicit MPTP-mediated necrosis and ferroptosis is explored. In the context of recent insights, the indistinct role of necroptosis signaling in tubular necrosis after ischemic kidney injury is scrutinized. We conclude by discussing the participation of p53, PARP1 and cyclophilin D and their overlapping pathways to elicit MPTP-mediated necrosis and ferroptosis in acute kidney injury.
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Affiliation(s)
- Yuan Ying
- Department of Cellular and Integrative Physiology, 985850 University of Nebraska Medical Center, Omaha, NE, 68198-5850, USA
| | - Babu J Padanilam
- Department of Cellular and Integrative Physiology, 985850 University of Nebraska Medical Center, Omaha, NE, 68198-5850, USA.
- Department of Internal Medicine, Division of Nephrology, University of Nebraska Medical Center, Omaha, NE, USA.
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41
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The transport mechanism of the mitochondrial ADP/ATP carrier. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2379-93. [PMID: 27001633 DOI: 10.1016/j.bbamcr.2016.03.015] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 12/18/2022]
Abstract
The mitochondrial ADP/ATP carrier imports ADP from the cytosol and exports ATP from the mitochondrial matrix, which are key transport steps for oxidative phosphorylation in eukaryotic organisms. The transport protein belongs to the mitochondrial carrier family, a large transporter family in the inner membrane of mitochondria. It is one of the best studied members of the family and serves as a paradigm for the molecular mechanism of mitochondrial carriers. Structurally, the carrier consists of three homologous domains, each composed of two transmembrane α-helices linked with a loop and short α-helix on the matrix side. The transporter cycles between a cytoplasmic and matrix state in which a central substrate binding site is alternately accessible to these compartments for binding of ADP or ATP. On both the cytoplasmic and matrix side of the carrier are networks consisting of three salt bridges each. In the cytoplasmic state, the matrix salt bridge network is formed and the cytoplasmic network is disrupted, opening the central substrate binding site to the intermembrane space and cytosol, whereas the converse occurs in the matrix state. In the transport cycle, tighter substrate binding in the intermediate states allows the interconversion of conformations by lowering the energy barrier for disruption and formation of these networks, opening and closing the carrier to either side of the membrane in an alternating way. Conversion between cytoplasmic and matrix states might require the simultaneous rotation of three domains around a central translocation pathway, constituting a unique mechanism among transport proteins. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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42
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Baburina Y, Azarashvili T, Grachev D, Krestinina O, Galvita A, Stricker R, Reiser G. Mitochondrial 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) interacts with mPTP modulators and functional complexes (I-V) coupled with release of apoptotic factors. Neurochem Int 2015; 90:46-55. [PMID: 26188334 DOI: 10.1016/j.neuint.2015.07.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 01/03/2023]
Abstract
We previously reported that 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) is present in rat brain and liver mitochondria, in the outer membrane and mitoplasts. Substrates of CNP, 2',3'-cAMP and 2',3'-cNADP, were found to accelerate opening of mitochondrial permeability transition pore (mPTP). In purified non-synaptic mitochondria, CNP was observed to co-immunoprecipitate with main modulators of mPTP, i.e. VDAC, ANT, and cyclophilin D, as well as with tubulin and COX IV. Using Blue Native Electrophoresis, with following Western blot, CNP was revealed to associate with functional inner membrane mitochondrial complexes I-V. In Ca(2+) -overloaded mitochondria, association of CNP with complexes I-V was decreased. Cyclosporine A increased the association of CNP with complexes I and III, supporting the idea of the involvement of these complexes in mPTP function. 2',3'-cAMP enhanced CNP dissociation from complexes I, III, IV and V in Ca(2+)-overloaded mitochondria (i.e. when pore is opened). Association of CNP with complexes I, III, IV, and V was shown in mitochondria isolated from brain, liver and heart. Stimulation of the opening of the non-selective pore in mitochondria correlated with CNP release from mitochondria in parallel with release of cytochrome c, AIF and Endo G. In Ca(2+)-overloaded mitochondria, 2',3'-cAMP further accelerated the release of AIF, Endo G and CNP, but did not alter cytochrome c release. These results provide strong evidence that CNP, one of the possible regulators of mPTP complex, might be involved in the control of respiration and energy production in mitochondria. This reveals a new function of CNP outside the myelin structure.
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Affiliation(s)
- Yulia Baburina
- Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Institut für Neurobiochemie (Institut für Inflammation und Neurodegeneration), Leipziger Straße 44, 39120 Magdeburg, Germany; Institute of Theoretical and Experimental Biophysics Russian Academy of Science, RU-142290 Pushchino, Moscow region, Russia
| | - Tamara Azarashvili
- Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Institut für Neurobiochemie (Institut für Inflammation und Neurodegeneration), Leipziger Straße 44, 39120 Magdeburg, Germany; Institute of Theoretical and Experimental Biophysics Russian Academy of Science, RU-142290 Pushchino, Moscow region, Russia
| | - Dmitry Grachev
- Institute of Theoretical and Experimental Biophysics Russian Academy of Science, RU-142290 Pushchino, Moscow region, Russia
| | - Olga Krestinina
- Institute of Theoretical and Experimental Biophysics Russian Academy of Science, RU-142290 Pushchino, Moscow region, Russia
| | - Anastasya Galvita
- Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Institut für Neurobiochemie (Institut für Inflammation und Neurodegeneration), Leipziger Straße 44, 39120 Magdeburg, Germany
| | - Rolf Stricker
- Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Institut für Neurobiochemie (Institut für Inflammation und Neurodegeneration), Leipziger Straße 44, 39120 Magdeburg, Germany
| | - Georg Reiser
- Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Institut für Neurobiochemie (Institut für Inflammation und Neurodegeneration), Leipziger Straße 44, 39120 Magdeburg, Germany.
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43
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Mitochondrial ATP synthasome: Expression and structural interaction of its components. Biochem Biophys Res Commun 2015; 464:787-93. [PMID: 26168732 DOI: 10.1016/j.bbrc.2015.07.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/07/2015] [Indexed: 11/20/2022]
Abstract
Mitochondrial ATP synthase, ADP/ATP translocase (ANT), and inorganic phosphate carrier (PiC) are supposed to form a supercomplex called ATP synthasome. Our protein and transcript analysis of rat tissues indicates that the expression of ANT and PiC is transcriptionally controlled in accordance with the biogenesis of ATP synthase. In contrast, the content of ANT and PiC is increased in ATP synthase deficient patients' fibroblasts, likely due to a post-transcriptional adaptive mechanism. A structural analysis of rat heart mitochondria by immunoprecipitation, blue native/SDS electrophoresis, immunodetection and MS analysis revealed the presence of ATP synthasome. However, the majority of PiC and especially ANT did not associate with ATP synthase, suggesting that most of PiC, ANT and ATP synthase exist as separate entities.
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44
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Gutiérrez-Aguilar M, Uribe-Carvajal S. The mitochondrial unselective channel in Saccharomyces cerevisiae. Mitochondrion 2015; 22:85-90. [PMID: 25889953 DOI: 10.1016/j.mito.2015.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 11/30/2022]
Abstract
Opening of the mitochondrial permeability transition (MPT) pore mediates the increase in the unselective permeability to ions and small molecules across the inner mitochondrial membrane. MPT results from the opening of channels of unknown identity in mitochondria from plants, animals and yeast. However, the effectors and conditions required for MPT to occur in different species are remarkably disparate. Here we critically review previous and recent findings concerning the mitochondrial unselective channel of the yeast Saccharomyces cerevisiae to determine if it can be considered a counterpart of the mammalian MPT pore.
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Affiliation(s)
- Manuel Gutiérrez-Aguilar
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA.
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45
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Bonora M, Wieckowski MR, Chinopoulos C, Kepp O, Kroemer G, Galluzzi L, Pinton P. Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition. Oncogene 2015; 34:1475-86. [PMID: 24727893 DOI: 10.1038/onc.2014.96] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 12/14/2022]
Abstract
The term mitochondrial permeability transition (MPT) is commonly used to indicate an abrupt increase in the permeability of the inner mitochondrial membrane to low molecular weight solutes. Widespread MPT has catastrophic consequences for the cell, de facto marking the boundary between cellular life and death. MPT results indeed in the structural and functional collapse of mitochondria, an event that commits cells to suicide via regulated necrosis or apoptosis. MPT has a central role in the etiology of both acute and chronic diseases characterized by the loss of post-mitotic cells. Moreover, cancer cells are often relatively insensitive to the induction of MPT, underlying their increased resistance to potentially lethal cues. Thus, intense efforts have been dedicated not only at the understanding of MPT in mechanistic terms, but also at the development of pharmacological MPT modulators. In this setting, multiple mitochondrial and extramitochondrial proteins have been suspected to critically regulate the MPT. So far, however, only peptidylprolyl isomerase F (best known as cyclophilin D) appears to constitute a key component of the so-called permeability transition pore complex (PTPC), the supramolecular entity that is believed to mediate MPT. Here, after reviewing the structural and functional features of the PTPC, we summarize recent findings suggesting that another of its core components is represented by the c subunit of mitochondrial ATP synthase.
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Affiliation(s)
- M Bonora
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
| | - M R Wieckowski
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - C Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - O Kepp
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - G Kroemer
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France [4] Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - L Galluzzi
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - P Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
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46
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Šubrtová K, Panicucci B, Zíková A. ATPaseTb2, a unique membrane-bound FoF1-ATPase component, is essential in bloodstream and dyskinetoplastic trypanosomes. PLoS Pathog 2015; 11:e1004660. [PMID: 25714685 PMCID: PMC4340940 DOI: 10.1371/journal.ppat.1004660] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 01/06/2015] [Indexed: 12/21/2022] Open
Abstract
In the infectious stage of Trypanosoma brucei, an important parasite of humans and livestock, the mitochondrial (mt) membrane potential (Δψm) is uniquely maintained by the ATP hydrolytic activity and subsequent proton pumping of the essential FoF1-ATPase. Intriguingly, this multiprotein complex contains several trypanosome-specific subunits of unknown function. Here, we demonstrate that one of the largest novel subunits, ATPaseTb2, is membrane-bound and localizes with monomeric and multimeric assemblies of the FoF1-ATPase. Moreover, RNAi silencing of ATPaseTb2 quickly leads to a significant decrease of the Δψm that manifests as a decreased growth phenotype, indicating that the FoF1-ATPase is impaired. To further explore the function of this protein, we employed a trypanosoma strain that lacks mtDNA (dyskinetoplastic, Dk) and thus subunit a, an essential component of the proton pore in the membrane Fo-moiety. These Dk cells generate the Δψm by combining the hydrolytic activity of the matrix-facing F1-ATPase and the electrogenic exchange of ATP4- for ADP3- by the ATP/ADP carrier (AAC). Surprisingly, in addition to the expected presence of F1-ATPase, the monomeric and multimeric FoF1-ATPase complexes were identified. In fact, the immunoprecipitation of a F1-ATPase subunit demonstrated that ATPaseTb2 was a component of these complexes. Furthermore, RNAi studies established that the membrane-bound ATPaseTb2 subunit is essential for maintaining normal growth and the Δψm of Dk cells. Thus, even in the absence of subunit a, a portion of the FoF1-ATPase is assembled in Dk cells.
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Affiliation(s)
- Karolína Šubrtová
- Institute of Parasitology, Biology Centre, CAS, České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre, CAS, České Budějovice, Czech Republic
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, CAS, České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Kwong JQ, Molkentin JD. Physiological and pathological roles of the mitochondrial permeability transition pore in the heart. Cell Metab 2015; 21:206-214. [PMID: 25651175 PMCID: PMC4616258 DOI: 10.1016/j.cmet.2014.12.001] [Citation(s) in RCA: 291] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prolonged mitochondrial permeability transition pore (MPTP) opening results in mitochondrial energetic dysfunction, organelle swelling, rupture, and typically a type of necrotic cell death. However, acute opening of the MPTP has a critical physiologic role in regulating mitochondrial Ca(2+) handling and metabolism. Despite the physiological and pathological roles that the MPTP orchestrates, the proteins that comprise the pore itself remain an area of ongoing investigation. Here, we will discuss the molecular composition of the MPTP and its role in regulating cardiac physiology and disease. A better understanding of MPTP structure and function will likely suggest novel cardioprotective therapeutic approaches.
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Affiliation(s)
- Jennifer Q Kwong
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA; Howard Hughes Medical Institute, Cincinnati, OH 45229, USA.
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The ADP/ATP carrier and its relationship to oxidative phosphorylation in ancestral protist trypanosoma brucei. EUKARYOTIC CELL 2015; 14:297-310. [PMID: 25616281 DOI: 10.1128/ec.00238-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The highly conserved ADP/ATP carrier (AAC) is a key energetic link between the mitochondrial (mt) and cytosolic compartments of all aerobic eukaryotic cells, as it exchanges the ATP generated inside the organelle for the cytosolic ADP. Trypanosoma brucei, a parasitic protist of medical and veterinary importance, possesses a single functional AAC protein (TbAAC) that is related to the human and yeast ADP/ATP carriers. However, unlike previous studies performed with these model organisms, this study showed that TbAAC is most likely not a stable component of either the respiratory supercomplex III+IV or the ATP synthasome but rather functions as a physically separate entity in this highly diverged eukaryote. Therefore, TbAAC RNA interference (RNAi) ablation in the insect stage of T. brucei does not impair the activity or arrangement of the respiratory chain complexes. Nevertheless, RNAi silencing of TbAAC caused a severe growth defect that coincides with a significant reduction of mt ATP synthesis by both substrate and oxidative phosphorylation. Furthermore, TbAAC downregulation resulted in a decreased level of cytosolic ATP, a higher mt membrane potential, an elevated amount of reactive oxygen species, and a reduced consumption of oxygen in the mitochondria. Interestingly, while TbAAC has previously been demonstrated to serve as the sole ADP/ATP carrier for ADP influx into the mitochondria, our data suggest that a second carrier for ATP influx may be present and active in the T. brucei mitochondrion. Overall, this study provides more insight into the delicate balance of the functional relationship between TbAAC and the oxidative phosphorylation (OXPHOS) pathway in an early diverged eukaryote.
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Killing multiple myeloma cells with the small molecule 3-bromopyruvate: implications for therapy. Anticancer Drugs 2015; 25:673-82. [PMID: 24557015 DOI: 10.1097/cad.0000000000000094] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The small molecule 3-bromopyruvate (3-BP), which has emerged recently as the first member of a new class of potent anticancer agents, was tested for its capacity to kill multiple myeloma (MM) cancer cells. Human MM cells (RPMI 8226) begin to lose viability significantly within 8 h of incubation in the presence of 3-BP. The Km (0.3 mmol/l) for intracellular accumulation of 3-BP in MM cells is 24 times lower than that in control cells (7.2 mmol/l). Therefore, the uptake of 3-BP by MM cells is significantly higher than that by peripheral blood mononuclear cells. Further, the IC50 values for human MM cells and control peripheral blood mononuclear cells are 24 and 58 µmol/l, respectively. Therefore, specificity and selectivity of 3-BP toward MM cancer cells are evident on the basis of the above. In MM cells the transcription levels of the gene encoding the monocarboxylate transporter MCT1 is significantly amplified compared with control cells. The level of intracellular ATP in MM cells decreases by over 90% within 1 h after addition of 100 µmol/l 3-BP. The cytotoxicity of 3-BP, exemplified by a marked decrease in viability of MM cells, is potentiated by the inhibitor of glutathione synthesis buthionine sulfoximine. In addition, the lack of mutagenicity and its superior capacity relative to Glivec to kill MM cancer cells are presented in this study.
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50
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Alavian KN, Dworetzky SI, Bonanni L, Zhang P, Sacchetti S, Li H, Signore AP, Smith PJS, Gribkoff VK, Jonas EA. The mitochondrial complex V-associated large-conductance inner membrane current is regulated by cyclosporine and dexpramipexole. Mol Pharmacol 2014; 87:1-8. [PMID: 25332381 DOI: 10.1124/mol.114.095661] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inefficiency of oxidative phosphorylation can result from futile leak conductance through the inner mitochondrial membrane. Stress or injury may exacerbate this leak conductance, putting cells, and particularly neurons, at risk of dysfunction and even death when energy demand exceeds cellular energy production. Using a novel method, we have recently described an ion conductance consistent with mitochondrial permeability transition pore (mPTP) within the c-subunit of the ATP synthase. Excitotoxicity, reactive oxygen species-producing stimuli, or elevated mitochondrial matrix calcium opens the channel, which is inhibited by cyclosporine A and ATP/ADP. Here we show that ATP and the neuroprotective drug dexpramipexole (DEX) inhibited an ion conductance consistent with this c-subunit channel (mPTP) in brain-derived submitochondrial vesicles (SMVs) enriched for F1FO ATP synthase (complex V). Treatment of SMVs with urea denatured extramembrane components of complex V, eliminated DEX- but not ATP-mediated current inhibition, and reduced binding of [(14)C]DEX. Direct effects of DEX on the synthesis and hydrolysis of ATP by complex V suggest that interaction of the compound with its target results in functional conformational changes in the enzyme complex. [(14)C]DEX bound specifically to purified recombinant b and oligomycin sensitivity-conferring protein subunits of the mitochondrial F1FO ATP synthase. Previous data indicate that DEX increased the efficiency of energy production in cells, including neurons. Taken together, these studies suggest that modulation of a complex V-associated inner mitochondrial membrane current is metabolically important and may represent an avenue for the development of new therapeutics for neurodegenerative disorders.
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Affiliation(s)
- Kambiz N Alavian
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Steven I Dworetzky
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Laura Bonanni
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Ping Zhang
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Silvio Sacchetti
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Hongmei Li
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Armando P Signore
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Peter J S Smith
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Valentin K Gribkoff
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
| | - Elizabeth A Jonas
- Department of Internal Medicine (K.N.A., P.Z., S.S., H.L., E.A.J.) and Department of Neurobiology (E.A.J.), Yale University School of Medicine, New Haven, Connecticut; Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom (K.N.A.); Department of Neuroscience, Imaging and Clinical Sciences, University G.d'Annunzio of Chieti-Pescara, Chieti-Pescara, Italy (L.B.); Knopp Biosciences LLC, Pittsburgh, Pennsylvania (S.I.D., A.P.S., V.K.G.); and Biocurrents Research Center, Marine Biological Laboratory, Woods Hole, Massachusetts (P.J.S.S.)
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