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Horten P, Song K, Garlich J, Hardt R, Colina-Tenorio L, Horvath SE, Schulte U, Fakler B, van der Laan M, Becker T, Stuart RA, Pfanner N, Rampelt H. Identification of MIMAS, a multifunctional mega-assembly integrating metabolic and respiratory biogenesis factors of mitochondria. Cell Rep 2024; 43:113772. [PMID: 38393949 PMCID: PMC11010658 DOI: 10.1016/j.celrep.2024.113772] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/03/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
The mitochondrial inner membrane plays central roles in bioenergetics and metabolism and contains several established membrane protein complexes. Here, we report the identification of a mega-complex of the inner membrane, termed mitochondrial multifunctional assembly (MIMAS). Its large size of 3 MDa explains why MIMAS has escaped detection in the analysis of mitochondria so far. MIMAS combines proteins of diverse functions from respiratory chain assembly to metabolite transport, dehydrogenases, and lipid biosynthesis but not the large established supercomplexes of the respiratory chain, ATP synthase, or prohibitin scaffold. MIMAS integrity depends on the non-bilayer phospholipid phosphatidylethanolamine, in contrast to respiratory supercomplexes whose stability depends on cardiolipin. Our findings suggest that MIMAS forms a protein-lipid mega-assembly in the mitochondrial inner membrane that integrates respiratory biogenesis and metabolic processes in a multifunctional platform.
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Affiliation(s)
- Patrick Horten
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Kuo Song
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Joshua Garlich
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Robert Hardt
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany
| | - Lilia Colina-Tenorio
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Susanne E Horvath
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Martin van der Laan
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine, Saarland University, 66421 Homburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany
| | - Rosemary A Stuart
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
| | - Heike Rampelt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
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2
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Vaglio-Garro A, Kozlov AV, Smirnova YD, Weidinger A. Pathological Interplay between Inflammation and Mitochondria Aggravates Glutamate Toxicity. Int J Mol Sci 2024; 25:2276. [PMID: 38396952 PMCID: PMC10889519 DOI: 10.3390/ijms25042276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/06/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Mitochondrial dysfunction and glutamate toxicity are associated with neural disorders, including brain trauma. A review of the literature suggests that toxic and transmission actions of neuronal glutamate are spatially and functionally separated. The transmission pathway utilizes synaptic GluN2A receptors, rapidly released pool of glutamate, evoked release of glutamate mediated by Synaptotagmin 1 and the amount of extracellular glutamate regulated by astrocytes. The toxic pathway utilizes extrasynaptic GluN2B receptors and a cytoplasmic pool of glutamate, which results from the spontaneous release of glutamate mediated by Synaptotagmin 7 and the neuronal 2-oxoglutarate dehydrogenase complex (OGDHC), a tricarboxylic acid (TCA) cycle enzyme. Additionally, the inhibition of OGDHC observed upon neuro-inflammation is due to an excessive release of reactive oxygen/nitrogen species by immune cells. The loss of OGDHC inhibits uptake of glutamate by mitochondria, thus facilitating its extracellular accumulation and stimulating toxic glutamate pathway without affecting transmission. High levels of extracellular glutamate lead to dysregulation of intracellular redox homeostasis and cause ferroptosis, excitotoxicity, and mitochondrial dysfunction. The latter affects the transmission pathway demanding high-energy supply and leading to cell death. Mitochondria aggravate glutamate toxicity due to impairments in the TCA cycle and become a victim of glutamate toxicity, which disrupts oxidative phosphorylation. Thus, therapies targeting the TCA cycle in neurological disorders may be more efficient than attempting to preserve mitochondrial oxidative phosphorylation.
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Affiliation(s)
- Annette Vaglio-Garro
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (Y.D.S.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Andrey V. Kozlov
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (Y.D.S.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Yuliya D. Smirnova
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (Y.D.S.); (A.W.)
- Laboratory of Metagenomics and Food Biotechnology, Voronezh State University of Engineering Technologies, 394036 Voronezh, Russia
| | - Adelheid Weidinger
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (Y.D.S.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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3
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Goyal S, Cambronne XA. Layered mechanisms regulating the human mitochondrial NAD+ transporter SLC25A51. Biochem Soc Trans 2023; 51:1989-2004. [PMID: 38108469 PMCID: PMC10802112 DOI: 10.1042/bst20220318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/28/2023] [Accepted: 12/08/2023] [Indexed: 12/19/2023]
Abstract
SLC25A51 is the primary mitochondrial NAD+ transporter in humans and controls many local reactions by mediating the influx of oxidized NAD+. Intriguingly, SLC25A51 lacks several key features compared with other members in the mitochondrial carrier family, thus its molecular mechanism has been unclear. A deeper understanding would shed light on the control of cellular respiration, the citric acid cycle, and free NAD+ concentrations in mammalian mitochondria. This review discusses recent insights into the transport mechanism of SLC25A51, and in the process highlights a multitiered regulation that governs NAD+ transport. The aspects regulating SLC25A51 import activity can be categorized as contributions from (1) structural characteristics of the transporter itself, (2) its microenvironment, and (3) distinctive properties of the transported ligand. These unique mechanisms further evoke compelling new ideas for modulating the activity of this transporter, as well as new mechanistic models for the mitochondrial carrier family.
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Affiliation(s)
- Shivansh Goyal
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712
| | - Xiaolu A. Cambronne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712
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4
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Fernandez-Fuente G, Overmyer KA, Lawton AJ, Kasza I, Shapiro SL, Gallego-Muñoz P, Coon JJ, Denu JM, Alexander CM, Puglielli L. The citrate transporters SLC13A5 and SLC25A1 elicit different metabolic responses and phenotypes in the mouse. Commun Biol 2023; 6:926. [PMID: 37689798 PMCID: PMC10492862 DOI: 10.1038/s42003-023-05311-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023] Open
Abstract
Cytosolic citrate is imported from the mitochondria by SLC25A1, and from the extracellular milieu by SLC13A5. In the cytosol, citrate is used by ACLY to generate acetyl-CoA, which can then be exported to the endoplasmic reticulum (ER) by SLC33A1. Here, we report the generation of mice with systemic overexpression (sTg) of SLC25A1 or SLC13A5. Both animals displayed increased cytosolic levels of citrate and acetyl-CoA; however, SLC13A5 sTg mice developed a progeria-like phenotype with premature death, while SLC25A1 sTg mice did not. Analysis of the metabolic profile revealed widespread differences. Furthermore, SLC13A5 sTg mice displayed increased engagement of the ER acetylation machinery through SLC33A1, while SLC25A1 sTg mice did not. In conclusion, our findings point to different biological responses to SLC13A5- or SLC25A1-mediated import of citrate and suggest that the directionality of the citrate/acetyl-CoA pathway can transduce different signals.
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Affiliation(s)
- Gonzalo Fernandez-Fuente
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Katherine A Overmyer
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
| | - Alexis J Lawton
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Ildiko Kasza
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Samantha L Shapiro
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Patricia Gallego-Muñoz
- Department of Cell Biology, Genetics, Histology and Pharmacology, Faculty of Medicine, University of Valladolid, Valladolid, Spain
| | - Joshua J Coon
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - John M Denu
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Caroline M Alexander
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA.
- Geriatric Research Education Clinical Center, Veterans Affairs Medical Center, Madison, WI, USA.
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA.
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5
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Odendaal C, Jager EA, Martines ACMF, Vieira-Lara MA, Huijkman NCA, Kiyuna LA, Gerding A, Wolters JC, Heiner-Fokkema R, van Eunen K, Derks TGJ, Bakker BM. Personalised modelling of clinical heterogeneity between medium-chain acyl-CoA dehydrogenase patients. BMC Biol 2023; 21:184. [PMID: 37667308 PMCID: PMC10478272 DOI: 10.1186/s12915-023-01652-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 06/21/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Monogenetic inborn errors of metabolism cause a wide phenotypic heterogeneity that may even differ between family members carrying the same genetic variant. Computational modelling of metabolic networks may identify putative sources of this inter-patient heterogeneity. Here, we mainly focus on medium-chain acyl-CoA dehydrogenase deficiency (MCADD), the most common inborn error of the mitochondrial fatty acid oxidation (mFAO). It is an enigma why some MCADD patients-if untreated-are at risk to develop severe metabolic decompensations, whereas others remain asymptomatic throughout life. We hypothesised that an ability to maintain an increased free mitochondrial CoA (CoASH) and pathway flux might distinguish asymptomatic from symptomatic patients. RESULTS We built and experimentally validated, for the first time, a kinetic model of the human liver mFAO. Metabolites were partitioned according to their water solubility between the bulk aqueous matrix and the inner membrane. Enzymes are also either membrane-bound or in the matrix. This metabolite partitioning is a novel model attribute and improved predictions. MCADD substantially reduced pathway flux and CoASH, the latter due to the sequestration of CoA as medium-chain acyl-CoA esters. Analysis of urine from MCADD patients obtained during a metabolic decompensation showed an accumulation of medium- and short-chain acylcarnitines, just like the acyl-CoA pool in the MCADD model. The model suggested some rescues that increased flux and CoASH, notably increasing short-chain acyl-CoA dehydrogenase (SCAD) levels. Proteome analysis of MCADD patient-derived fibroblasts indeed revealed elevated levels of SCAD in a patient with a clinically asymptomatic state. This is a rescue for MCADD that has not been explored before. Personalised models based on these proteomics data confirmed an increased pathway flux and CoASH in the model of an asymptomatic patient compared to those of symptomatic MCADD patients. CONCLUSIONS We present a detailed, validated kinetic model of mFAO in human liver, with solubility-dependent metabolite partitioning. Personalised modelling of individual patients provides a novel explanation for phenotypic heterogeneity among MCADD patients. Further development of personalised metabolic models is a promising direction to improve individualised risk assessment, management and monitoring for inborn errors of metabolism.
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Affiliation(s)
- Christoff Odendaal
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Emmalie A Jager
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
- Section of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Anne-Claire M F Martines
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Marcel A Vieira-Lara
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Nicolette C A Huijkman
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Ligia A Kiyuna
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Albert Gerding
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
- Department of Laboratory Medicine, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Justina C Wolters
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Karen van Eunen
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Terry G J Derks
- Section of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.
| | - Barbara M Bakker
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.
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6
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Skulachev VP, Vyssokikh MY, Chernyak BV, Mulkidjanian AY, Skulachev MV, Shilovsky GA, Lyamzaev KG, Borisov VB, Severin FF, Sadovnichii VA. Six Functions of Respiration: Isn't It Time to Take Control over ROS Production in Mitochondria, and Aging Along with It? Int J Mol Sci 2023; 24:12540. [PMID: 37628720 PMCID: PMC10454651 DOI: 10.3390/ijms241612540] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/04/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Cellular respiration is associated with at least six distinct but intertwined biological functions. (1) biosynthesis of ATP from ADP and inorganic phosphate, (2) consumption of respiratory substrates, (3) support of membrane transport, (4) conversion of respiratory energy to heat, (5) removal of oxygen to prevent oxidative damage, and (6) generation of reactive oxygen species (ROS) as signaling molecules. Here we focus on function #6, which helps the organism control its mitochondria. The ROS bursts typically occur when the mitochondrial membrane potential (MMP) becomes too high, e.g., due to mitochondrial malfunction, leading to cardiolipin (CL) oxidation. Depending on the intensity of CL damage, specific programs for the elimination of damaged mitochondria (mitophagy), whole cells (apoptosis), or organisms (phenoptosis) can be activated. In particular, we consider those mechanisms that suppress ROS generation by enabling ATP synthesis at low MMP levels. We discuss evidence that the mild depolarization mechanism of direct ATP/ADP exchange across mammalian inner and outer mitochondrial membranes weakens with age. We review recent data showing that by protecting CL from oxidation, mitochondria-targeted antioxidants decrease lethality in response to many potentially deadly shock insults. Thus, targeting ROS- and CL-dependent pathways may prevent acute mortality and, hopefully, slow aging.
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Affiliation(s)
- Vladimir P. Skulachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
| | - Mikhail Yu. Vyssokikh
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
| | - Boris V. Chernyak
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
| | | | - Maxim V. Skulachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
- Institute of Mitoengineering, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Gregory A. Shilovsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Kharkevich Institute for Information Transmission Problems of the Russian Academy of Sciences, 127051 Moscow, Russia
| | - Konstantin G. Lyamzaev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
- The “Russian Clinical Research Center for Gerontology” of the Ministry of Healthcare of the Russian Federation, Pirogov Russian National Research Medical University, 129226 Moscow, Russia
| | - Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
| | - Fedor F. Severin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.P.S.); (M.Y.V.); (B.V.C.); (M.V.S.); (G.A.S.); (K.G.L.); (F.F.S.)
| | - Victor A. Sadovnichii
- Faculty of Mechanics and Mathematics, Lomonosov Moscow State University, 119991 Moscow, Russia;
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7
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Holeček M. Roles of malate and aspartate in gluconeogenesis in various physiological and pathological states. Metabolism 2023:155614. [PMID: 37286128 DOI: 10.1016/j.metabol.2023.155614] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 06/09/2023]
Abstract
Gluconeogenesis, a pathway for glucose synthesis from non-carbohydrate substances, begins with the synthesis of oxaloacetate (OA) from pyruvate and intermediates of citric acid cycle in hepatocyte mitochondria. The traditional view is that OA does not cross the mitochondrial membrane and must be shuttled to the cytosol, where most enzymes involved in gluconeogenesis are compartmentalized, in the form of malate. Thus, the possibility of transporting OA in the form of aspartate has been ignored. In the article is shown that malate supply to the cytosol increases only when fatty acid oxidation in the liver is activated, such as during starvation or untreated diabetes. Alternatively, aspartate synthesized from OA by mitochondrial aspartate aminotransferase (AST) is transported to the cytosol in exchange for glutamate via the aspartate-glutamate carrier 2 (AGC2). If the main substrate for gluconeogenesis is an amino acid, aspartate is converted to OA via urea cycle, therefore, ammonia detoxification and gluconeogenesis are simultaneously activated. If the main substrate is lactate, OA is synthesized by cytosolic AST, glutamate is transported to the mitochondria through AGC2, and nitrogen is not lost. It is concluded that, compared to malate, aspartate is a more suitable form of OA transport from the mitochondria for gluconeogenesis.
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Affiliation(s)
- Milan Holeček
- Department of Physiology, Charles University, Faculty of Medicine in Hradec Králové, Czech Republic.
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8
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Weidinger A, Milivojev N, Hosmann A, Duvigneau JC, Szabo C, Törö G, Rauter L, Vaglio-Garro A, Mkrtchyan GV, Trofimova L, Sharipov RR, Surin AM, Krasilnikova IA, Pinelis VG, Tretter L, Moldzio R, Bayır H, Kagan VE, Bunik VI, Kozlov AV. Oxoglutarate dehydrogenase complex controls glutamate-mediated neuronal death. Redox Biol 2023; 62:102669. [PMID: 36933393 PMCID: PMC10031542 DOI: 10.1016/j.redox.2023.102669] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 03/14/2023] Open
Abstract
Brain injury is accompanied by neuroinflammation, accumulation of extracellular glutamate and mitochondrial dysfunction, all of which cause neuronal death. The aim of this study was to investigate the impact of these mechanisms on neuronal death. Patients from the neurosurgical intensive care unit suffering aneurysmal subarachnoid hemorrhage (SAH) were recruited retrospectively from a respective database. In vitro experiments were performed in rat cortex homogenate, primary dissociated neuronal cultures, B35 and NG108-15 cell lines. We employed methods including high resolution respirometry, electron spin resonance, fluorescent microscopy, kinetic determination of enzymatic activities and immunocytochemistry. We found that elevated levels of extracellular glutamate and nitric oxide (NO) metabolites correlated with poor clinical outcome in patients with SAH. In experiments using neuronal cultures we showed that the 2-oxoglutarate dehydrogenase complex (OGDHC), a key enzyme of the glutamate-dependent segment of the tricarboxylic acid (TCA) cycle, is more susceptible to the inhibition by NO than mitochondrial respiration. Inhibition of OGDHC by NO or by succinyl phosphonate (SP), a highly specific OGDHC inhibitor, caused accumulation of extracellular glutamate and neuronal death. Extracellular nitrite did not substantially contribute to this NO action. Reactivation of OGDHC by its cofactor thiamine (TH) reduced extracellular glutamate levels, Ca2+ influx into neurons and cell death rate. Salutary effect of TH against glutamate toxicity was confirmed in three different cell lines. Our data suggest that the loss of control over extracellular glutamate, as described here, rather than commonly assumed impaired energy metabolism, is the critical pathological manifestation of insufficient OGDHC activity, leading to neuronal death.
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Affiliation(s)
- Adelheid Weidinger
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Nadja Milivojev
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Arthur Hosmann
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - J Catharina Duvigneau
- Institute for Medical Biochemistry, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Csaba Szabo
- University of Fribourg, Section of Science and Medicine, Department of Oncology, Microbiology and Immunology, Section of Pharmacology, Fribourg, Switzerland; Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, USA
| | - Gabor Törö
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, USA
| | - Laurin Rauter
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Annette Vaglio-Garro
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Garik V Mkrtchyan
- A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234, Moscow, Russia
| | - Lidia Trofimova
- Biological Faculty, Department of Biophysics, Lomonosov Moscow State University, Moscow, Russia
| | - Rinat R Sharipov
- Institute of General Pathology and Pathophysiology, Laboratory of Fundamental and Applied Problems of Pain, Moscow, Russia
| | - Alexander M Surin
- Institute of General Pathology and Pathophysiology, Laboratory of Fundamental and Applied Problems of Pain, Moscow, Russia; National Medical Research Center of Children's Health, Russian Ministry of Health, Laboratory of Neurobiology and Brain Development, Moscow, Russia
| | - Irina A Krasilnikova
- National Medical Research Center of Children's Health, Russian Ministry of Health, Laboratory of Neurobiology and Brain Development, Moscow, Russia
| | - Vsevolod G Pinelis
- National Medical Research Center of Children's Health, Russian Ministry of Health, Laboratory of Neurobiology and Brain Development, Moscow, Russia
| | - Laszlo Tretter
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Rudolf Moldzio
- Institute for Medical Biochemistry, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Hülya Bayır
- Departments of Environmental and Occupational Health, Pharmacology and Chemical Biology, Chemistry and Center for Free Radical and Antioxidant Health University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, Safar Center for Resuscitation Research, Children's Neuroscience Institute, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA
| | - Valerian E Kagan
- Departments of Environmental and Occupational Health, Pharmacology and Chemical Biology, Chemistry and Center for Free Radical and Antioxidant Health University of Pittsburgh, Pittsburgh, PA, USA
| | - Victoria I Bunik
- A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234, Moscow, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia; Department of Biochemistry, Sechenov University, Moscow, Russia
| | - Andrey V Kozlov
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria.
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9
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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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10
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Li H, Liang Z, Li Y, Wen J, Zhang R. Molecular docking and molecular dynamics simulation study on the toxicity mechanism of bongkrekic acid. Toxicon 2023; 223:107021. [PMID: 36621683 DOI: 10.1016/j.toxicon.2023.107021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/14/2022] [Accepted: 01/02/2023] [Indexed: 01/07/2023]
Abstract
BKA belongs to gram-negative brevibacterium. It can cause poisoning in humans or animals and can be fatal in severe cases. There are few investigations on toxic mechanisms of BKA because of foodborne factors. MD simulations were used to study the stability and intermolecular interactions of BKA and ANT complexes to reveal the mechanism of BKA in this paper. BKA blocked ANT protein translocation mainly through Van der Waals force, hydrophobic and hydrogen bonding interactions by the MD simulations. The conformational flexibility of the complex system during different simulation times indicated that BKA affected the conformational changes of ANT through strong interactions of hydrogen bonds with active domain residues Gln-93, Tyr-196, Arg-287 and Arg-245. The results of binding free energy, principal component analysis, hydrophobic interactions and root-mean-square fluctuation showed that the prominent binding force of Tyr-196 with C26 of BKA was significant to the toxicity. The active site interactions analysis indicated that the essential positively charged polar amino acids which play a crucial role within the active site of the ANT protein undergo conformational changes with BKA as the branch point.
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Affiliation(s)
- Hongmei Li
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Zhen Liang
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Ying Li
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Jiazhen Wen
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Rong Zhang
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China.
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11
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Intracellular Citrate/acetyl-CoA flux and endoplasmic reticulum acetylation: Connectivity is the answer. Mol Metab 2022; 67:101653. [PMID: 36513219 PMCID: PMC9792894 DOI: 10.1016/j.molmet.2022.101653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/29/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Key cellular metabolites reflecting the immediate activity of metabolic enzymes as well as the functional metabolic state of intracellular organelles can act as powerful signal regulators to ensure the activation of homeostatic responses. The citrate/acetyl-CoA pathway, initially recognized for its role in intermediate metabolism, has emerged as a fundamental branch of this nutrient-sensing homeostatic response. Emerging studies indicate that fluctuations in acetyl-CoA availability within different cellular organelles and compartments provides substrate-level regulation of many biological functions. A fundamental aspect of these regulatory functions involves Nε-lysine acetylation. SCOPE OF REVIEW Here, we will examine the emerging regulatory functions of the citrate/acetyl-CoA pathway and the specific role of the endoplasmic reticulum (ER) acetylation machinery in the maintenance of intracellular crosstalk and homeostasis. These functions will be analyzed in the context of associated human diseases and specific mouse models of dysfunctional ER acetylation and citrate/acetyl-CoA flux. A primary objective of this review is to highlight the complex yet integrated response of compartment- and organelle-specific Nε-lysine acetylation to the intracellular availability and flux of acetyl-CoA, linking this important post-translational modification to cellular metabolism. MAJOR CONCLUSIONS The ER acetylation machinery regulates the proteostatic functions of the organelle as well as the metabolic crosstalk between different intracellular organelles and compartments. This crosstalk enables the cell to impart adaptive responses within the ER and the secretory pathway. However, it also enables the ER to impart adaptive responses within different cellular organelles and compartments. Defects in the homeostatic balance of acetyl-CoA flux and ER acetylation reflect different but converging disease states in humans as well as converging phenotypes in relevant mouse models. In conclusion, citrate and acetyl-CoA should not only be seen as metabolic substrates of intermediate metabolism but also as signaling molecules that direct functional adaptation of the cell to both intracellular and extracellular messages. Future discoveries in CoA biology and acetylation are likely to yield novel therapeutic approaches.
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12
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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: 67] [Impact Index Per Article: 33.5] [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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13
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Citrate Regulates the Saccharomyces cerevisiae Mitochondrial GDP/GTP Carrier (Ggc1p) by Triggering Unidirectional Transport of GTP. J Fungi (Basel) 2022; 8:jof8080795. [PMID: 36012783 PMCID: PMC9410265 DOI: 10.3390/jof8080795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 02/01/2023] Open
Abstract
The yeast mitochondrial transport of GTP and GDP is mediated by Ggc1p, a member of the mitochondrial carrier family. The physiological role of Ggc1p in S. cerevisiae is probably to transport GTP into mitochondria in exchange for GDP generated in the matrix. ggc1Δ cells exhibit lower levels of GTP and increased levels of GDP in mitochondria, are unable to grow on nonfermentable substrates and lose mtDNA. Because in yeast, succinyl-CoA ligase produces ATP instead of GTP, and the mitochondrial nucleoside diphosphate kinase is localized in the intermembrane space, Ggc1p is the only supplier of mitochondrial GTP required for the maturation of proteins containing Fe-S clusters, such as aconitase [4Fe-4S] and ferredoxin [2Fe-2S]. In this work, it was demonstrated that citrate is a regulator of purified and reconstituted Ggc1p by trans-activating unidirectional transport of GTP across the proteoliposomal membrane. It was also shown that the binding site of Ggc1p for citrate is different from the binding site for the substrate GTP. It is proposed that the citrate-induced GTP uniport (CIGU) mediated by Ggc1p is involved in the homeostasis of the guanine nucleotide pool in the mitochondrial matrix.
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14
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Monné M, Marobbio CMT, Agrimi G, Palmieri L, Palmieri F. Mitochondrial transport and metabolism of the major methyl donor and versatile cofactor S-adenosylmethionine, and related diseases: A review †. IUBMB Life 2022; 74:573-591. [PMID: 35730628 DOI: 10.1002/iub.2658] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/19/2022] [Indexed: 11/08/2022]
Abstract
S-adenosyl-L-methionine (SAM) is a coenzyme and the most commonly used methyl-group donor for the modification of metabolites, DNA, RNA and proteins. SAM biosynthesis and SAM regeneration from the methylation reaction product S-adenosyl-L-homocysteine (SAH) take place in the cytoplasm. Therefore, the intramitochondrial SAM-dependent methyltransferases require the import of SAM and export of SAH for recycling. Orthologous mitochondrial transporters belonging to the mitochondrial carrier family have been identified to catalyze this antiport transport step: Sam5p in yeast, SLC25A26 (SAMC) in humans, and SAMC1-2 in plants. In mitochondria SAM is used by a vast number of enzymes implicated in the following processes: the regulation of replication, transcription, translation, and enzymatic activities; the maturation and assembly of mitochondrial tRNAs, ribosomes and protein complexes; and the biosynthesis of cofactors, such as ubiquinone, lipoate, and molybdopterin. Mutations in SLC25A26 and mitochondrial SAM-dependent enzymes have been found to cause human diseases, which emphasizes the physiological importance of these proteins.
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Affiliation(s)
- Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,Department of Sciences, University of Basilicata, Potenza, Italy
| | - Carlo M T Marobbio
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Gennaro Agrimi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Luigi Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
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15
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Miniero DV, Monné M, Di Noia MA, Palmieri L, Palmieri F. Evidence for Non-Essential Salt Bridges in the M-Gates of Mitochondrial Carrier Proteins. Int J Mol Sci 2022; 23:ijms23095060. [PMID: 35563451 PMCID: PMC9104175 DOI: 10.3390/ijms23095060] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial carriers, which transport metabolites, nucleotides, and cofactors across the mitochondrial inner membrane, have six transmembrane α-helices enclosing a translocation pore with a central substrate binding site whose access is controlled by a cytoplasmic and a matrix gate (M-gate). The salt bridges formed by the three PX[DE]XX[RK] motifs located on the odd-numbered transmembrane α-helices greatly contribute to closing the M-gate. We have measured the transport rates of cysteine mutants of the charged residue positions in the PX[DE]XX[RK] motifs of the bovine oxoglutarate carrier, the yeast GTP/GDP carrier, and the yeast NAD+ transporter, which all lack one of these charged residues. Most single substitutions, including those of the non-charged and unpaired charged residues, completely inactivated transport. Double mutations of charged pairs showed that all three carriers contain salt bridges non-essential for activity. Two double substitutions of these non-essential charge pairs exhibited higher transport rates than their corresponding single mutants, whereas swapping the charged residues in these positions did not increase activity. The results demonstrate that some of the residues in the charged residue positions of the PX[DE]XX[KR] motifs are important for reasons other than forming salt bridges, probably for playing specific roles related to the substrate interaction-mediated conformational changes leading to the M-gate opening/closing.
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Affiliation(s)
- Daniela Valeria Miniero
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
- Department of Sciences, University of Basilicata, Via Ateneo Lucano 10, 85100 Potenza, Italy
| | - Maria Antonietta Di Noia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
| | - Luigi Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
- Correspondence: (L.P.); (F.P.)
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
- Correspondence: (L.P.); (F.P.)
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16
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Li N, Xu H, Liu X, Gao R, He J, Ding Y, Li F, Geng Y, Mu X, Chen X. Exposure to benzo(a)pyrene suppresses mitophagy via ANT1-PINK1-Parkin pathway in ovarian corpus luteum during early pregnancy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:152759. [PMID: 34986425 DOI: 10.1016/j.scitotenv.2021.152759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/17/2021] [Accepted: 12/25/2021] [Indexed: 06/14/2023]
Abstract
Exposure to benzo (a)pyrene (BaP) has been confirmed to interfere with embryo implantation. As the primary organ of progesterone synthesis during early pregnancy, the ovarian corpus luteum (CL) is essential for embryo implantation and pregnancy maintenance. We previously demonstrated that BaP impaired luteal function, but the molecular mechanism remains unclear. In CL cells, mitochondria are the main sites of progesterone synthesis. Mitophagy, a particular type of autophagy, regulates mitochondrial quality by degrading damaged mitochondria and ensuring the homeostasis of cell physiology. Therefore, the present study investigated the effects and the potential molecular mechanisms of BaP on ovarian mitophagy during early pregnancy. We found that BaP and its metabolite, BPDE, inhibited autophagy and PINK1/Parkin-mediated mitophagy in the pregnant ovaries and luteinized granulosa cell, KGN. Notably, adenine nucleotide translocator 1 (ANT1), a crucial mediator of PINK1-dependent mitophagy, was suppressed by BaP and BPDE both in vivo and in vitro. The inhibition of ANT1 leads to the decrease in the PINK1 bound to the outer membrane of mitochondria and consequently reduces recruitment of Parkin to the mitochondria, which is required for the subsequent clearance of mitochondria. Meanwhile, exposure to BPDE also damaged mitochondrial function, causing the reduction in mitochondrial potential and ATP production. Overexpression of ANT1 in KGN cells partially relieved the inhibition of mitophagy caused by BPDE, restored mitochondrial function and expression of hormone synthesis-associated genes. Collectively, our study firstly clarified that BaP and BPDE suppress mitophagy of CL cells via the ANT1-PINK1-Parkin pathway, which provides a new insight to explore the detailed mechanism of the BaP-induced ovarian toxicity.
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Affiliation(s)
- Nanyan Li
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China
| | - Hanting Xu
- Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China; College of Basic Medicine, Chongqing Medical University, Chongqing 400016, PR China
| | - Xueqing Liu
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China
| | - Rufei Gao
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China
| | - Junlin He
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China
| | - Yubin Ding
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China
| | - Fangfang Li
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China
| | - Yanqing Geng
- Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China; College of Basic Medicine, Chongqing Medical University, Chongqing 400016, PR China
| | - Xinyi Mu
- Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China; College of Basic Medicine, Chongqing Medical University, Chongqing 400016, PR China
| | - Xuemei Chen
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, PR China; Joint International Research Laboratory of Reproduction & Development, Chongqing Medical University, Chongqing 400016, PR China.
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17
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Palmieri F, Monné M, Fiermonte G, Palmieri L. Mitochondrial transport and metabolism of the vitamin B-derived cofactors thiamine pyrophosphate, coenzyme A, FAD and NAD + , and related diseases: A review. IUBMB Life 2022; 74:592-617. [PMID: 35304818 PMCID: PMC9311062 DOI: 10.1002/iub.2612] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 01/19/2023]
Abstract
Multiple mitochondrial matrix enzymes playing key roles in metabolism require cofactors for their action. Due to the high impermeability of the mitochondrial inner membrane, these cofactors need to be synthesized within the mitochondria or be imported, themselves or one of their precursors, into the organelles. Transporters belonging to the protein family of mitochondrial carriers have been identified to transport the coenzymes: thiamine pyrophosphate, coenzyme A, FAD and NAD+ , which are all structurally similar to nucleotides and derived from different B-vitamins. These mitochondrial cofactors bind more or less tightly to their enzymes and, after having been involved in a specific reaction step, are regenerated, spontaneously or by other enzymes, to return to their active form, ready for the next catalysis round. Disease-causing mutations in the mitochondrial cofactor carrier genes compromise not only the transport reaction but also the activity of all mitochondrial enzymes using that particular cofactor and the metabolic pathways in which the cofactor-dependent enzymes are involved. The mitochondrial transport, metabolism and diseases of the cofactors thiamine pyrophosphate, coenzyme A, FAD and NAD+ are the focus of this review.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,Department of Sciences, University of Basilicata, Potenza, Italy
| | - Giuseppe Fiermonte
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
| | - Luigi Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
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18
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Jhawar S, Arakawa Y, Kumar S, Varghese D, Kim YS, Roper N, Elloumi F, Pommier Y, Pacak K, Del Rivero J. New Insights on the Genetics of Pheochromocytoma and Paraganglioma and Its Clinical Implications. Cancers (Basel) 2022; 14:cancers14030594. [PMID: 35158861 PMCID: PMC8833412 DOI: 10.3390/cancers14030594] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Pheochromocytoma and paraganglioma (together PPGL) are rare neuroendocrine tumors that arise from chromaffin tissue and produce catecholamines. Approximately 40% of cases of PPGL carry a germline mutation, suggesting that they have a high degree of heritability. The underlying mutation influences the PPGL clinical presentation such as cell differentiation, specific catecholamine production, tumor location, malignant potential and genetic anticipation, which helps to better understand the clinical course and tailor treatment accordingly. Genetic testing for pheochromocytoma and paraganglioma allows an early detection of hereditary syndromes and facilitates a close follow-up of high-risk patients. In this review article, we present the most recent advances in the field of genetics and we discuss the latest guidelines on the surveillance of asymptomatic SDHx mutation carriers. Abstract Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors that arise from chromaffin cells. PHEOs arise from the adrenal medulla, whereas PGLs arise from the neural crest localized outside the adrenal gland. Approximately 40% of all cases of PPGLs (pheochromocytomas/paragangliomas) are associated with germline mutations and 30–40% display somatic driver mutations. The mutations associated with PPGLs can be classified into three groups. The pseudohypoxic group or cluster I includes the following genes: SDHA, SDHB, SDHC, SDHD, SDHAF2, FH, VHL, IDH1/2, MHD2, EGLN1/2 and HIF2/EPAS; the kinase group or cluster II includes RET, NF1, TMEM127, MAX and HRAS; and the Wnt signaling group or cluster III includes CSDE1 and MAML3. Underlying mutations can help understand the clinical presentation, overall prognosis and surveillance follow-up. Here we are discussing the new genetic insights of PPGLs.
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Affiliation(s)
- Sakshi Jhawar
- Life Bridge Health Center, Internal Medicine Program, Sinai Hospital of Baltimore, Baltimore, MD 21215, USA
| | - Yasuhiro Arakawa
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Suresh Kumar
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Diana Varghese
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Yoo Sun Kim
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Nitin Roper
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Fathi Elloumi
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Yves Pommier
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Karel Pacak
- Section on Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Jaydira Del Rivero
- Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
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19
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Jasper L, Scarcia P, Rust S, Reunert J, Palmieri F, Marquardt T. Uridine Treatment of the First Known Case of SLC25A36 Deficiency. Int J Mol Sci 2021; 22:ijms22189929. [PMID: 34576089 PMCID: PMC8470663 DOI: 10.3390/ijms22189929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 11/16/2022] Open
Abstract
SLC25A36 is a pyrimidine nucleotide carrier playing an important role in maintaining mitochondrial biogenesis. Deficiencies in SLC25A36 in mouse embryonic stem cells have been associated with mtDNA depletion as well as mitochondrial dysfunction. In human beings, diseases triggered by SLC25A36 mutations have not been described yet. We report the first known case of SLC25A36 deficiency in a 12-year-old patient with hypothyroidism, hyperinsulinism, hyperammonemia, chronical obstipation, short stature, along with language and general developmental delay. Whole exome analysis identified the homozygous mutation c.803dupT, p.Ser269llefs*35 in the SLC25A36 gene. Functional analysis of mutant SLC25A36 protein in proteoliposomes showed a virtually abolished transport activity. Immunoblotting results suggest that the mutant SLC25A36 protein in the patient undergoes fast degradation. Supplementation with oral uridine led to an improvement of thyroid function and obstipation, increase of growth and developmental progress. Our findings suggest an important role of SLC25A36 in hormonal regulations and oral uridine as a safe and effective treatment.
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Affiliation(s)
- Luisa Jasper
- Department of Pediatrics, University Hospital of Münster, Albert-Schweitzer-Campus 1, Gebäude A13, 48149 Münster, Germany; (L.J.); (S.R.); (J.R.)
| | - Pasquale Scarcia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy;
| | - Stephan Rust
- Department of Pediatrics, University Hospital of Münster, Albert-Schweitzer-Campus 1, Gebäude A13, 48149 Münster, Germany; (L.J.); (S.R.); (J.R.)
| | - Janine Reunert
- Department of Pediatrics, University Hospital of Münster, Albert-Schweitzer-Campus 1, Gebäude A13, 48149 Münster, Germany; (L.J.); (S.R.); (J.R.)
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy;
- Correspondence: (F.P.); (T.M.)
| | - Thorsten Marquardt
- Department of Pediatrics, University Hospital of Münster, Albert-Schweitzer-Campus 1, Gebäude A13, 48149 Münster, Germany; (L.J.); (S.R.); (J.R.)
- Correspondence: (F.P.); (T.M.)
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20
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Welcome to the Family: Identification of the NAD + Transporter of Animal Mitochondria as Member of the Solute Carrier Family SLC25. Biomolecules 2021; 11:biom11060880. [PMID: 34198503 PMCID: PMC8231866 DOI: 10.3390/biom11060880] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
Subcellular compartmentation is a fundamental property of eukaryotic cells. Communication and metabolic and regulatory interconnectivity between organelles require that solutes can be transported across their surrounding membranes. Indeed, in mammals, there are hundreds of genes encoding solute carriers (SLCs) which mediate the selective transport of molecules such as nucleotides, amino acids, and sugars across biological membranes. Research over many years has identified the localization and preferred substrates of a large variety of SLCs. Of particular interest has been the SLC25 family, which includes carriers embedded in the inner membrane of mitochondria to secure the supply of these organelles with major metabolic intermediates and coenzymes. The substrate specificity of many of these carriers has been established in the past. However, the route by which animal mitochondria are supplied with NAD+ had long remained obscure. Only just recently, the existence of a human mitochondrial NAD+ carrier was firmly established. With the realization that SLC25A51 (or MCART1) represents the major mitochondrial NAD+ carrier in mammals, a long-standing mystery in NAD+ biology has been resolved. Here, we summarize the functional importance and structural features of this carrier as well as the key observations leading to its discovery.
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Kell DB. A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation. Adv Microb Physiol 2021; 78:1-177. [PMID: 34147184 DOI: 10.1016/bs.ampbs.2021.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in the same, closed membrane. These views are correct. The textbooks also state that, according to the chemiosmotic coupling hypothesis, a (or the) kinetically and thermodynamically competent intermediate linking the two half-reactions is the electrochemical difference of protons that is in equilibrium with that between the two bulk phases that the coupling membrane serves to separate. This gradient consists of a membrane potential term Δψ and a pH gradient term ΔpH, and is known colloquially as the protonmotive force or pmf. Artificial imposition of a pmf can drive phosphorylation, but only if the pmf exceeds some 150-170mV; to achieve in vivo rates the imposed pmf must reach 200mV. The key question then is 'does the pmf generated by electron transport exceed 200mV, or even 170mV?' The possibly surprising answer, from a great many kinds of experiment and sources of evidence, including direct measurements with microelectrodes, indicates it that it does not. Observable pH changes driven by electron transport are real, and they control various processes; however, compensating ion movements restrict the Δψ component to low values. A protet-based model, that I outline here, can account for all the necessary observations, including all of those inconsistent with chemiosmotic coupling, and provides for a variety of testable hypotheses by which it might be refined.
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Affiliation(s)
- Douglas B Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative, Biology, University of Liverpool, Liverpool, United Kingdom; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
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Tonazzi A, Giangregorio N, Console L, Palmieri F, Indiveri C. The Mitochondrial Carnitine Acyl-carnitine Carrier (SLC25A20): Molecular Mechanisms of Transport, Role in Redox Sensing and Interaction with Drugs. Biomolecules 2021; 11:biom11040521. [PMID: 33807231 PMCID: PMC8066319 DOI: 10.3390/biom11040521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 12/22/2022] Open
Abstract
The SLC25A20 transporter, also known as carnitine acyl-carnitine carrier (CAC), catalyzes the transport of short, medium and long carbon chain acyl-carnitines across the mitochondrial inner membrane in exchange for carnitine. The 30-year story of the protein responsible for this function started with its purification from rat liver mitochondria. Even though its 3D structure is not yet available, CAC is one of the most deeply characterized transport proteins of the inner mitochondrial membrane. Other than functional, kinetic and mechanistic data, post-translational modifications regulating the transport activity of CAC have been revealed. CAC interactions with drugs or xenobiotics relevant to human health and toxicology and the response of the carrier function to dietary compounds have been discovered. Exploiting combined approaches of site-directed mutagenesis with chemical targeting and bioinformatics, a large set of data on structure/function relationships have been obtained, giving novel information on the molecular mechanism of the transport catalyzed by this protein.
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Affiliation(s)
- Annamaria Tonazzi
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
| | - Nicola Giangregorio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
| | - Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy;
| | - Ferdinando Palmieri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
- Correspondence: (F.P.); (C.I.); Tel.: +39-080-544-3323 (F.P.); Tel.: +39-0984-492939 (C.I.)
| | - Cesare Indiveri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy;
- Correspondence: (F.P.); (C.I.); Tel.: +39-080-544-3323 (F.P.); Tel.: +39-0984-492939 (C.I.)
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23
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Pleiotropic effects of alpha-ketoglutarate as a potential anti-ageing agent. Ageing Res Rev 2021; 66:101237. [PMID: 33340716 DOI: 10.1016/j.arr.2020.101237] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/23/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023]
Abstract
An intermediate of tricarboxylic acid cycle alpha-ketoglutarate (AKG) is involved in pleiotropic metabolic and regulatory pathways in the cell, including energy production, biosynthesis of certain amino acids, collagen biosynthesis, epigenetic regulation of gene expression, regulation of redox homeostasis, and detoxification of hazardous substances. Recently, AKG supplement was found to extend lifespan and delay the onset of age-associated decline in experimental models such as nematodes, fruit flies, yeasts, and mice. This review summarizes current knowledge on metabolic and regulatory functions of AKG and its potential anti-ageing effects. Impact on epigenetic regulation of ageing via being an obligate substrate of DNA and histone demethylases, direct antioxidant properties, and function as mimetic of caloric restriction and hormesis-induced agent are among proposed mechanisms of AKG geroprotective action. Due to influence on mitochondrial respiration, AKG can stimulate production of reactive oxygen species (ROS) by mitochondria. According to hormesis hypothesis, moderate stimulation of ROS production could have rather beneficial biological effects, than detrimental ones, because of the induction of defensive mechanisms that improve resistance to stressors and age-related diseases and slow down functional senescence. Discrepancies found in different models and limitations of AKG as a geroprotective drug are discussed.
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Škulj S, Brkljača Z, Kreiter J, Pohl EE, Vazdar M. Molecular Dynamics Simulations of Mitochondrial Uncoupling Protein 2. Int J Mol Sci 2021; 22:ijms22031214. [PMID: 33530558 PMCID: PMC7866055 DOI: 10.3390/ijms22031214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 11/16/2022] Open
Abstract
Molecular dynamics (MD) simulations of uncoupling proteins (UCP), a class of transmembrane proteins relevant for proton transport across inner mitochondrial membranes, represent a complicated task due to the lack of available structural data. In this work, we use a combination of homology modelling and subsequent microsecond molecular dynamics simulations of UCP2 in the DOPC phospholipid bilayer, starting from the structure of the mitochondrial ATP/ADP carrier (ANT) as a template. We show that this protocol leads to a structure that is impermeable to water, in contrast to MD simulations of UCP2 structures based on the experimental NMR structure. We also show that ATP binding in the UCP2 cavity is tight in the homology modelled structure of UCP2 in agreement with experimental observations. Finally, we corroborate our results with conductance measurements in model membranes, which further suggest that the UCP2 structure modeled from ANT protein possesses additional key functional elements, such as a fatty acid-binding site at the R60 region of the protein, directly related to the proton transport mechanism across inner mitochondrial membranes.
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Affiliation(s)
- Sanja Škulj
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
| | - Jürgen Kreiter
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, 1210 Vienna, Austria;
| | - Elena E. Pohl
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, 1210 Vienna, Austria;
- Correspondence: (E.E.P.); (M.V.)
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague, Czech Republic
- Correspondence: (E.E.P.); (M.V.)
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25
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The metabolic importance of the glutaminase II pathway in normal and cancerous cells. Anal Biochem 2020; 644:114083. [PMID: 33352190 DOI: 10.1016/j.ab.2020.114083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/08/2020] [Accepted: 12/15/2020] [Indexed: 02/08/2023]
Abstract
In rapidly dividing cells, including many cancer cells, l-glutamine is a major energy source. Utilization of glutamine is usually depicted as: l-glutamine → l-glutamate (catalyzed by glutaminase isozymes; GLS1 and GLS2), followed by l-glutamate → α-ketoglutarate [catalyzed by glutamate-linked aminotransferases or by glutamate dehydrogenase (GDH)]. α-Ketoglutarate is a major anaplerotic component of the tricarboxylic acid (TCA) cycle. However, the glutaminase II pathway also converts l-glutamine to α-ketoglutarate. This pathway consists of a glutamine transaminase coupled to ω-amidase [Net reaction: l-Glutamine + α-keto acid + H2O → α-ketoglutarate + l-amino acid + NH4+]. This review focuses on the biological importance of the glutaminase II pathway, especially in relation to metabolism of cancer cells. Our studies suggest a component enzyme of the glutaminase II pathway, ω-amidase, is utilized by tumor cells to provide anaplerotic carbon. Inhibitors of GLS1 are currently in clinical trials as anti-cancer agents. However, this treatment will not prevent the glutaminase II pathway from providing anaplerotic carbon derived from glutamine. Specific inhibitors of ω-amidase, perhaps in combination with a GLS1 inhibitor, may provide greater therapeutic efficacy.
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26
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Biochemical and functional characterization of a mitochondrial citrate carrier in Arabidopsis thaliana. Biochem J 2020; 477:1759-1777. [PMID: 32329787 DOI: 10.1042/bcj20190785] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022]
Abstract
A homolog of the mitochondrial succinate/fumarate carrier from yeast (Sfc1p) has been found in the Arabidopsis genome, named AtSFC1. The AtSFC1 gene was expressed in Escherichia coli, and the gene product was purified and reconstituted in liposomes. Its transport properties and kinetic parameters demonstrated that AtSFC1 transports citrate, isocitrate and aconitate and, to a lesser extent, succinate and fumarate. This carrier catalyzes a fast counter-exchange transport as well as a low uniport of substrates, exhibits a higher transport affinity for tricarboxylates than dicarboxylates, and is inhibited by pyridoxal 5'-phosphate and other inhibitors of mitochondrial carriers to various degrees. Gene expression analysis indicated that the AtSFC1 transcript is mainly present in heterotrophic tissues, and fusion with a green-fluorescent protein localized AtSFC1 to the mitochondria. Furthermore, 35S-AtSFC1 antisense lines were generated and characterized at metabolic and physiological levels in different organs and at various developmental stages. Lower expression of AtSFC1 reduced seed germination and impaired radicle growth, a phenotype that was related to reduced respiration rate. These findings demonstrate that AtSFC1 might be involved in storage oil mobilization at the early stages of seedling growth and in nitrogen assimilation in root tissue by catalyzing citrate/isocitrate or citrate/succinate exchanges.
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27
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Peroxisomal Cofactor Transport. Biomolecules 2020; 10:biom10081174. [PMID: 32806597 PMCID: PMC7463629 DOI: 10.3390/biom10081174] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 12/20/2022] Open
Abstract
Peroxisomes are eukaryotic organelles that are essential for growth and development. They are highly metabolically active and house many biochemical reactions, including lipid metabolism and synthesis of signaling molecules. Most of these metabolic pathways are shared with other compartments, such as Endoplasmic reticulum (ER), mitochondria, and plastids. Peroxisomes, in common with all other cellular organelles are dependent on a wide range of cofactors, such as adenosine 5′-triphosphate (ATP), Coenzyme A (CoA), and nicotinamide adenine dinucleotide (NAD). The availability of the peroxisomal cofactor pool controls peroxisome function. The levels of these cofactors available for peroxisomal metabolism is determined by the balance between synthesis, import, export, binding, and degradation. Since the final steps of cofactor synthesis are thought to be located in the cytosol, cofactors must be imported into peroxisomes. This review gives an overview about our current knowledge of the permeability of the peroxisomal membrane with the focus on ATP, CoA, and NAD. Several members of the mitochondrial carrier family are located in peroxisomes, catalyzing the transfer of these organic cofactors across the peroxisomal membrane. Most of the functions of these peroxisomal cofactor transporters are known from studies in yeast, humans, and plants. Parallels and differences between the transporters in the different organisms are discussed here.
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28
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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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29
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Horten P, Colina-Tenorio L, Rampelt H. Biogenesis of Mitochondrial Metabolite Carriers. Biomolecules 2020; 10:E1008. [PMID: 32645990 PMCID: PMC7408425 DOI: 10.3390/biom10071008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/28/2022] Open
Abstract
: Metabolite carriers of the mitochondrial inner membrane are crucial for cellular physiology since mitochondria contribute essential metabolic reactions and synthesize the majority of the cellular ATP. Like almost all mitochondrial proteins, carriers have to be imported into mitochondria from the cytosol. Carrier precursors utilize a specialized translocation pathway dedicated to the biogenesis of carriers and related proteins, the carrier translocase of the inner membrane (TIM22) pathway. After recognition and import through the mitochondrial outer membrane via the translocase of the outer membrane (TOM) complex, carrier precursors are ushered through the intermembrane space by hexameric TIM chaperones and ultimately integrated into the inner membrane by the TIM22 carrier translocase. Recent advances have shed light on the mechanisms of TOM translocase and TIM chaperone function, uncovered an unexpected versatility of the machineries, and revealed novel components and functional crosstalk of the human TIM22 translocase.
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Affiliation(s)
- Patrick Horten
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (P.H.); (L.C.-T.)
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Lilia Colina-Tenorio
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (P.H.); (L.C.-T.)
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Heike Rampelt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (P.H.); (L.C.-T.)
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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30
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Bround MJ, Bers DM, Molkentin JD. A 20/20 view of ANT function in mitochondrial biology and necrotic cell death. J Mol Cell Cardiol 2020; 144:A3-A13. [PMID: 32454061 DOI: 10.1016/j.yjmcc.2020.05.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/16/2020] [Accepted: 05/20/2020] [Indexed: 12/25/2022]
Abstract
The adenosine nucleotide translocase (ANT) family of proteins are inner mitochondrial membrane proteins involved in energy homeostasis and cell death. The primary function of ANT proteins is to exchange cytosolic ADP with matrix ATP, facilitating the export of newly synthesized ATP to the cell while providing new ADP substrate to the mitochondria. As such, the ANT proteins are central to maintaining energy homeostasis in all eukaryotic cells. Evidence also suggests that the ANTs constitute a pore-forming component of the mitochondrial permeability transition pore (MPTP), a structure that forms in the inner mitochondrial membrane that is thought to underlie regulated necrotic cell death. Additionally, emerging studies suggest that ANT proteins are also critical for mitochondrial uncoupling and for promoting mitophagy. Thus, the ANTs are multifunctional proteins that are poised to participate in several aspects of mitochondrial biology and the greater regulation of cell death, which will be discussed here.
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Affiliation(s)
- Michael J Bround
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, 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 Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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31
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Palmieri F, Scarcia P, Monné M. Diseases Caused by Mutations in Mitochondrial Carrier Genes SLC25: A Review. Biomolecules 2020; 10:biom10040655. [PMID: 32340404 PMCID: PMC7226361 DOI: 10.3390/biom10040655] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
In the 1980s, after the mitochondrial DNA (mtDNA) had been sequenced, several diseases resulting from mtDNA mutations emerged. Later, numerous disorders caused by mutations in the nuclear genes encoding mitochondrial proteins were found. A group of these diseases are due to defects of mitochondrial carriers, a family of proteins named solute carrier family 25 (SLC25), that transport a variety of solutes such as the reagents of ATP synthase (ATP, ADP, and phosphate), tricarboxylic acid cycle intermediates, cofactors, amino acids, and carnitine esters of fatty acids. The disease-causing mutations disclosed in mitochondrial carriers range from point mutations, which are often localized in the substrate translocation pore of the carrier, to large deletions and insertions. The biochemical consequences of deficient transport are the compartmentalized accumulation of the substrates and dysfunctional mitochondrial and cellular metabolism, which frequently develop into various forms of myopathy, encephalopathy, or neuropathy. Examples of diseases, due to mitochondrial carrier mutations are: combined D-2- and L-2-hydroxyglutaric aciduria, carnitine-acylcarnitine carrier deficiency, hyperornithinemia-hyperammonemia-homocitrillinuria (HHH) syndrome, early infantile epileptic encephalopathy type 3, Amish microcephaly, aspartate/glutamate isoform 1 deficiency, congenital sideroblastic anemia, Fontaine progeroid syndrome, and citrullinemia type II. Here, we review all the mitochondrial carrier-related diseases known until now, focusing on the connections between the molecular basis, altered metabolism, and phenotypes of these inherited disorders.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
- Correspondence: (F.P.); (M.M.); Tel.: +39-0805443323 (F.P.)
| | - Pasquale Scarcia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
- Department of Sciences, University of Basilicata, via Ateneo Lucano 10, 85100 Potenza, Italy
- Correspondence: (F.P.); (M.M.); Tel.: +39-0805443323 (F.P.)
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32
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Hu X, Go YM, Jones DP. Omics Integration for Mitochondria Systems Biology. Antioxid Redox Signal 2020; 32:853-872. [PMID: 31891667 PMCID: PMC7074923 DOI: 10.1089/ars.2019.8006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Abstract
Significance: Elucidation of the central importance of mitophagy in homeostasis of cells and organisms emphasizes that mitochondrial functions extend far beyond short-term needs for energy production. In mitochondria systems biology, the mitochondrial genome, proteome, and metabolome operate as a functional network in coordination of cell activities. Organization occurs through subnetworks that are interconnected by membrane potential, transport activities, allosteric and cooperative interactions, redox signaling mechanisms, rheostatic control by post-translational modifications, and metal ion homeostasis. These subnetworks enable use of varied energy precursors, defense against environmental stressors, and macromolecular rewiring to titrate energy production, biosynthesis, and detoxification according to cell-specific needs. Rewiring mechanisms, termed mitochondrial reprogramming, enhance fitness to respond to metabolic resources and challenges from the environment. Maladaptive responses can cause cell death. Maladaptive rewiring can cause disease. In cancer, adaptive rewiring can interfere with effective treatment. Recent Advances: Many recent advances have been facilitated by the development of new omics tools, which create opportunities to use data-driven analysis of omics data to address these complex adaptive and maladaptive mechanisms of mitochondrial reprogramming in human disease. Critical Issues: Application of omics integration to model systems reveals a critical role for metal ion homeostasis broadly impacting mitochondrial reprogramming. Importantly, data show that trans-omics associations are more robust and biologically relevant than single omics associations. Future Directions: Application of omics integration to mitophagy research creates new opportunities to link the complex, interactive functions of mitochondrial form and function in mitochondria systems biology.
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Affiliation(s)
- Xin Hu
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia
| | - Young-Mi Go
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia
| | - Dean P. Jones
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia
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Antonio K, Valdez MMN, Mercado-Asis L, Taïeb D, Pacak K. Pheochromocytoma/paraganglioma: recent updates in genetics, biochemistry, immunohistochemistry, metabolomics, imaging and therapeutic options. Gland Surg 2020; 9:105-123. [PMID: 32206603 DOI: 10.21037/gs.2019.10.25] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pheochromocytomas and paragangliomas (PPGLs), rare chromaffin/neural crest cell tumors, are commonly benign in their clinical presentation. However, there are a number of cases presenting as metastatic and their diagnosis and management becomes a dilemma because of their rarity. PPGLs are constantly evolving entities in the field of endocrinology brought about by endless research and discoveries, especially in genetics. Throughout the years, our knowledge and perception of these tumors and their genetic background has greatly expanded and changed, and each new discovery leads to advancement in the diagnosis, treatment and follow-up of PPGLs. In this review, we discuss the recent updates in the genetics, biochemistry, immunohistochemistry, metabolomics, imaging and treatment options of PPGLs.
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Affiliation(s)
- Karren Antonio
- Section on Medical Neuroendocrinology, The Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Division of Endocrinology, University of Santo Tomas Hospital, Manila, Philippines
| | - Ma Margarita Noreen Valdez
- Section on Medical Neuroendocrinology, The Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Division of Endocrinology, University of Santo Tomas Hospital, Manila, Philippines
| | | | - David Taïeb
- Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Aix-Marseille University, Marseille, France
| | - Karel Pacak
- Section on Medical Neuroendocrinology, The Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Mitochondrial Carriers for Aspartate, Glutamate and Other Amino Acids: A Review. Int J Mol Sci 2019; 20:ijms20184456. [PMID: 31510000 PMCID: PMC6769469 DOI: 10.3390/ijms20184456] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/05/2019] [Accepted: 09/06/2019] [Indexed: 12/19/2022] Open
Abstract
Members of the mitochondrial carrier (MC) protein family transport various molecules across the mitochondrial inner membrane to interlink steps of metabolic pathways and biochemical processes that take place in different compartments; i.e., are localized partly inside and outside the mitochondrial matrix. MC substrates consist of metabolites, inorganic anions (such as phosphate and sulfate), nucleotides, cofactors and amino acids. These compounds have been identified by in vitro transport assays based on the uptake of radioactively labeled substrates into liposomes reconstituted with recombinant purified MCs. By using this approach, 18 human, plant and yeast MCs for amino acids have been characterized and shown to transport aspartate, glutamate, ornithine, arginine, lysine, histidine, citrulline and glycine with varying substrate specificities, kinetics, influences of the pH gradient, and capacities for the antiport and uniport mode of transport. Aside from providing amino acids for mitochondrial translation, the transport reactions catalyzed by these MCs are crucial in energy, nitrogen, nucleotide and amino acid metabolism. In this review we dissect the transport properties, phylogeny, regulation and expression levels in different tissues of MCs for amino acids, and summarize the main structural aspects known until now about MCs. The effects of their disease-causing mutations and manipulation of their expression levels in cells are also considered as clues for understanding their physiological functions.
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Ruprecht JJ, Kunji ER. Structural changes in the transport cycle of the mitochondrial ADP/ATP carrier. Curr Opin Struct Biol 2019; 57:135-144. [PMID: 31039524 PMCID: PMC6700394 DOI: 10.1016/j.sbi.2019.03.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/15/2019] [Accepted: 03/20/2019] [Indexed: 11/27/2022]
Abstract
The mitochondrial ADP/ATP carrier, also called adenine nucleotide translocase, accomplishes one of the most important transport activities in eukaryotic cells, importing ADP into the mitochondrial matrix for ATP synthesis, and exporting ATP to fuel cellular activities. In the transport cycle, the carrier changes between a cytoplasmic and matrix state, in which the central substrate binding site is alternately accessible to these compartments. A structure of a cytoplasmic state was known, but recently, a structure of a matrix-state in complex with bongkrekic acid was solved. Comparison of the two states explains the function of highly conserved sequence features and reveals that the transport mechanism is unique, involving the coordinated movement of six dynamic elements around a central translocation pathway.
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Affiliation(s)
- Jonathan J Ruprecht
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
| | - Edmund Rs Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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36
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Deletion of Neuronal GLT-1 in Mice Reveals Its Role in Synaptic Glutamate Homeostasis and Mitochondrial Function. J Neurosci 2019; 39:4847-4863. [PMID: 30926746 DOI: 10.1523/jneurosci.0894-18.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 02/07/2019] [Accepted: 03/10/2019] [Indexed: 01/19/2023] Open
Abstract
The glutamate transporter GLT-1 is highly expressed in astrocytes but also in neurons, primarily in axon terminals. We generated a conditional neuronal GLT-1 KO using synapsin 1-Cre (synGLT-1 KO) to elucidate the metabolic functions of GLT-1 expressed in neurons, here focusing on the cerebral cortex. Both synaptosomal uptake studies and electron microscopic immunocytochemistry demonstrated knockdown of GLT-1 in the cerebral cortex in the synGLT-1 KO mice. Aspartate content was significantly reduced in cerebral cortical extracts as well as synaptosomes from cerebral cortex of synGLT-1 KO compared with control littermates. 13C-Labeling of tricarboxylic acid cycle intermediates originating from metabolism of [U-13C]-glutamate was significantly reduced in synGLT-1 KO synaptosomes. The decreased aspartate content was due to diminished entry of glutamate into the tricarboxylic acid cycle. Pyruvate recycling, a pathway necessary for full glutamate oxidation, was also decreased. ATP production was significantly increased, despite unaltered oxygen consumption, in isolated mitochondria from the synGLT-1 KO. The density of mitochondria in axon terminals and perisynaptic astrocytes was increased in the synGLT-1 KO. Intramitochondrial cristae density of synGLT-1 KO mice was increased, suggesting increased mitochondrial efficiency, perhaps in compensation for reduced access to glutamate. SynGLT-1 KO synaptosomes exhibited an elevated oxygen consumption rate when stimulated with veratridine, despite a lower baseline oxygen consumption rate in the presence of glucose. GLT-1 expressed in neurons appears to be required to provide glutamate to synaptic mitochondria and is linked to neuronal energy metabolism and mitochondrial function.SIGNIFICANCE STATEMENT All synaptic transmitters need to be cleared from the extracellular space after release, and transporters are used to clear glutamate released from excitatory synapses. GLT-1 is the major glutamate transporter, and most GLT-1 is expressed in astrocytes. Only 5%-10% is expressed in neurons, primarily in axon terminals. The function of GLT-1 in axon terminals remains unknown. Here, we used a conditional KO approach to investigate the significance of the expression of GLT-1 in neurons. We found multiple abnormalities of mitochondrial function, suggesting impairment of glutamate utilization by synaptic mitochondria in the neuronal GLT-1 KO. These data suggest that GLT-1 expressed in axon terminals may be important in maintaining energy metabolism and biosynthetic activities mediated by presynaptic mitochondria.
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Ruprecht JJ, King MS, Zögg T, Aleksandrova AA, Pardon E, Crichton PG, Steyaert J, Kunji ERS. The Molecular Mechanism of Transport by the Mitochondrial ADP/ATP Carrier. Cell 2019; 176:435-447.e15. [PMID: 30611538 PMCID: PMC6349463 DOI: 10.1016/j.cell.2018.11.025] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/25/2018] [Accepted: 11/16/2018] [Indexed: 11/30/2022]
Abstract
Mitochondrial ADP/ATP carriers transport ADP into the mitochondrial matrix for ATP synthesis, and ATP out to fuel the cell, by cycling between cytoplasmic-open and matrix-open states. The structure of the cytoplasmic-open state is known, but it has proved difficult to understand the transport mechanism in the absence of a structure in the matrix-open state. Here, we describe the structure of the matrix-open state locked by bongkrekic acid bound in the ADP/ATP-binding site at the bottom of the central cavity. The cytoplasmic side of the carrier is closed by conserved hydrophobic residues, and a salt bridge network, braced by tyrosines. Glycine and small amino acid residues allow close-packing of helices on the matrix side. Uniquely, the carrier switches between states by rotation of its three domains about a fulcrum provided by the substrate-binding site. Because these features are highly conserved, this mechanism is likely to apply to the whole mitochondrial carrier family. Video Abstract
Structure of the matrix-open state of the mitochondrial ADP/ATP carrier solved The inhibitor bongkrekic acid locks the state by occupying the substrate-binding site Conformational changes during transport are highly dynamic, using six mobile elements Roles of all conserved sequence features in mitochondrial carriers are now explained
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Affiliation(s)
- Jonathan J Ruprecht
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
| | - Martin S King
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Thomas Zögg
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Antoniya A Aleksandrova
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Els Pardon
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Paul G Crichton
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Jan Steyaert
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Edmund R S Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
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Spinelli JB, Haigis MC. The multifaceted contributions of mitochondria to cellular metabolism. Nat Cell Biol 2018; 20:745-754. [PMID: 29950572 PMCID: PMC6541229 DOI: 10.1038/s41556-018-0124-1] [Citation(s) in RCA: 883] [Impact Index Per Article: 147.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/17/2018] [Indexed: 02/07/2023]
Abstract
Although classically appreciated for their role as the powerhouse of the cell, the metabolic functions of mitochondria reach far beyond bioenergetics. In this Review, we discuss how mitochondria catabolize nutrients for energy, generate biosynthetic precursors for macromolecules, compartmentalize metabolites for the maintenance of redox homeostasis and function as hubs for metabolic waste management. We address the importance of these roles in both normal physiology and in disease.
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Affiliation(s)
- Jessica B Spinelli
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Ludwig Center, Harvard Medical School, Boston, MA, USA
| | - Marcia C Haigis
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
- Ludwig Center, Harvard Medical School, Boston, MA, USA.
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Darbani B, Kell DB, Borodina I. Energetic evolution of cellular Transportomes. BMC Genomics 2018; 19:418. [PMID: 29848286 PMCID: PMC5977736 DOI: 10.1186/s12864-018-4816-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Transporter proteins mediate the translocation of substances across the membranes of living cells. Many transport processes are energetically expensive and the cells use 20 to 60% of their energy to power the transportomes. We hypothesized that there may be an evolutionary selection pressure for lower energy transporters. RESULTS We performed a genome-wide analysis of the compositional reshaping of the transportomes across the kingdoms of bacteria, archaea, and eukarya. We found that the share of ABC transporters is much higher in bacteria and archaea (ca. 27% of the transportome) than in primitive eukaryotes (13%), algae and plants (10%) and in fungi and animals (5-6%). This decrease is compensated by an increased occurrence of secondary transporters and ion channels. The share of ion channels is particularly high in animals (ca. 30% of the transportome) and algae and plants with (ca. 13%), when compared to bacteria and archaea with only 6-7%. Therefore, our results show a move to a preference for the low-energy-demanding transporters (ion channels and carriers) over the more energy-costly transporter classes (ATP-dependent families, and ABCs in particular) as part of the transition from prokaryotes to eukaryotes. The transportome analysis also indicated seven bacterial species, including Neorickettsia risticii and Neorickettsia sennetsu, as likely origins of the mitochondrion in eukaryotes, based on the phylogenetically restricted presence therein of clear homologues of modern mitochondrial solute carriers. CONCLUSIONS The results indicate that the transportomes of eukaryotes evolved strongly towards a higher energetic efficiency, as ATP-dependent transporters diminished and secondary transporters and ion channels proliferated. These changes have likely been important in the development of tissues performing energetically costly cellular functions.
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Affiliation(s)
- Behrooz Darbani
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Douglas B. Kell
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN UK
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark
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Buffet A, Morin A, Castro-Vega LJ, Habarou F, Lussey-Lepoutre C, Letouzé E, Lefebvre H, Guilhem I, Haissaguerre M, Raingeard I, Padilla-Girola M, Tran T, Tchara L, Bertherat J, Amar L, Ottolenghi C, Burnichon N, Gimenez-Roqueplo AP, Favier J. Germline Mutations in the Mitochondrial 2-Oxoglutarate/Malate Carrier SLC25A11 Gene Confer a Predisposition to Metastatic Paragangliomas. Cancer Res 2018; 78:1914-1922. [PMID: 29431636 DOI: 10.1158/0008-5472.can-17-2463] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/14/2017] [Accepted: 01/31/2018] [Indexed: 11/16/2022]
Abstract
Comprehensive genetic analyses have identified germline SDHB and FH gene mutations as predominant causes of metastatic paraganglioma and pheochromocytoma. However, some suspicious cases remain unexplained. In this study, we performed whole-exome sequencing of a paraganglioma exhibiting an SDHx-like molecular profile in the absence of SDHx or FH mutations and identified a germline mutation in the SLC25A11 gene, which encodes the mitochondrial 2-oxoglutarate/malate carrier. Germline SLC25A11 mutations were identified in six other patients, five of whom had metastatic disease. These mutations were associated with loss of heterozygosity, suggesting that SLC25A11 acts as a tumor-suppressor gene. Pseudohypoxic and hypermethylator phenotypes comparable with those described in SDHx- and FH-related tumors were observed both in tumors with mutated SLC25A11 and in Slc25a11Δ/Δ immortalized mouse chromaffin knockout cells generated by CRISPR-Cas9 technology. These data show that SLC25A11 is a novel paraganglioma susceptibility gene for which loss of function correlates with metastatic presentation.Significance: A gene encoding a mitochondrial carrier is implicated in a hereditary cancer predisposition syndrome, expanding the role of mitochondrial dysfunction in paraganglioma. Cancer Res; 78(8); 1914-22. ©2018 AACR.
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Affiliation(s)
- Alexandre Buffet
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Aurélie Morin
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Luis-Jaime Castro-Vega
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Florence Habarou
- Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Necker-Enfants Malades, Service de Biochimie Métabolique, Paris, France
| | - Charlotte Lussey-Lepoutre
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Eric Letouzé
- Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Programme Cartes d'Identité des Tumeurs, Ligue Nationale Contre Le Cancer, Paris, France.,INSERM, UMR-1162, Génomique Fonctionnelle des Tumeurs Solides, Equipe Labellisée Ligue Contre le Cancer, Institut Universitaire d'Hématologie, Paris, France.,Université Paris 13, Sorbonne Paris Cité, Unité de Formation et de Recherche Santé, Médecine, Biologie Humaine, Bobigny, France.,Université Paris Diderot, Paris, France
| | - Hervé Lefebvre
- Service d'Endocrinologie, Diabète et Maladies Métaboliques, INSERM U982, Centre Hospitalier Universitaire de Rouen, Rouen Cedex, France
| | - Isabelle Guilhem
- Service d'Endocrinologie-Diabétologie-Nutrition, CHU de Rennes, Hôpital Sud, Rennes, France
| | | | - Isabelle Raingeard
- Service d'Endocrinologie, CHU Montpellier, Hôpital Lapeyronie, Montpellier Cedex 5, France
| | - Mathilde Padilla-Girola
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer
| | - Thi Tran
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Lucien Tchara
- Assistance Publique-Hôpitaux de Paris, Hôpital Necker-Enfants Malades, Service de Biochimie Métabolique, Paris, France
| | - Jérôme Bertherat
- Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Service d'Endocrinologie "Centre de référence maladies rares de la surrénale", Hôpital Cochin, Assistance Publique, Hôpitaux de Paris, Paris, France.,Centre Expert National COMETE-Cancer de la surrénale, Paris, France
| | - Laurence Amar
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Centre Expert National COMETE-Cancer de la surrénale, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'hypertension artérielle et médecine vasculaire, Paris, France
| | - Chris Ottolenghi
- Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Necker-Enfants Malades, Service de Biochimie Métabolique, Paris, France
| | - Nelly Burnichon
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer.,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
| | - Anne-Paule Gimenez-Roqueplo
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer. .,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France.,Centre Expert National COMETE-Cancer de la surrénale, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
| | - Judith Favier
- INSERM, UMR970, Paris-Centre de Recherche Cardiovasculaire, Paris, France; Equipe labellisée Ligue contre le Cancer. .,Université Paris Descartes, PRES Sorbonne Paris Cité, Faculté de Médecine, Paris, France
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Sengers Syndrome-Associated Mitochondrial Acylglycerol Kinase Is a Subunit of the Human TIM22 Protein Import Complex. Mol Cell 2017; 67:457-470.e5. [DOI: 10.1016/j.molcel.2017.06.014] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/28/2017] [Accepted: 06/13/2017] [Indexed: 11/19/2022]
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Ravasz D, Kacso G, Fodor V, Horvath K, Adam-Vizi V, Chinopoulos C. Catabolism of GABA, succinic semialdehyde or gamma-hydroxybutyrate through the GABA shunt impair mitochondrial substrate-level phosphorylation. Neurochem Int 2017; 109:41-53. [PMID: 28300620 DOI: 10.1016/j.neuint.2017.03.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 10/20/2022]
Abstract
GABA is catabolized in the mitochondrial matrix through the GABA shunt, encompassing transamination to succinic semialdehyde followed by oxidation to succinate by the concerted actions of GABA transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH), respectively. Gamma-hydroxybutyrate (GHB) is a neurotransmitter and a psychoactive drug that could enter the citric acid cycle through transhydrogenation with α-ketoglutarate to succinic semialdehyde and d-hydroxyglutarate, a reaction catalyzed by hydroxyacid-oxoacid transhydrogenase (HOT). Here, we tested the hypothesis that the elevation in matrix succinate concentration caused by exogenous addition of GABA, succinic semialdehyde or GHB shifts the equilibrium of the reversible reaction catalyzed by succinate-CoA ligase towards ATP (or GTP) hydrolysis, effectively negating substrate-level phosphorylation (SLP). Mitochondrial SLP was addressed by interrogating the directionality of the adenine nucleotide translocase during anoxia in isolated mouse brain and liver mitochondria. GABA eliminated SLP, and this was rescued by the GABA-T inhibitors vigabatrin and aminooxyacetic acid. Succinic semialdehyde was an extremely efficient substrate energizing mitochondria during normoxia but mimicked GABA in abolishing SLP in anoxia, in a manner refractory to vigabatrin and aminooxyacetic acid. GHB could moderately energize liver but not brain mitochondria consistent with the scarcity of HOT expression in the latter. In line with these results, GHB abolished SLP in liver but not brain mitochondria during anoxia and this was unaffected by either vigabatrin or aminooxyacetic acid. It is concluded that when mitochondria catabolize GABA or succinic semialdehyde or GHB through the GABA shunt, their ability to perform SLP is impaired.
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Affiliation(s)
- Dora Ravasz
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Gergely Kacso
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Viktoria Fodor
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Kata Horvath
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Laboratory for Neurobiochemistry, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary.
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Kooijman EE, Swim LA, Graber ZT, Tyurina YY, Bayır H, Kagan VE. Magic angle spinning 31P NMR spectroscopy reveals two essentially identical ionization states for the cardiolipin phosphates in phospholipid liposomes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:61-68. [PMID: 27984017 PMCID: PMC5362297 DOI: 10.1016/j.bbamem.2016.10.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 10/20/2016] [Accepted: 10/25/2016] [Indexed: 01/04/2023]
Abstract
Specific membrane lipid composition is crucial for optimized structural and functional organization of biological membranes. Cardiolipin is a unique phospholipid and important component of the inner mitochondrial membrane. It is involved in energy metabolism, inner mitochondrial membrane transport, regulation of multiple metabolic reactions and apoptotic cell death. The physico-chemical properties of cardiolipin have been studied extensively but despite all these efforts there is still lingering controversy regarding the ionization of the two phosphate groups of cardiolipin. Results obtained in the 1990s and early 2000s suggested that cardiolipin has two disparate pKa values where one of the protons was proposed to be stabilized by an intramolecular hydrogen bond. This has led to extensive speculations on the roles of these two putative ionization states of cardiolipin in mitochondria. More recently the notion of two pKa values has been challenged and rejected by several groups. These studies relied on external measurements of proton adsorption or electrophoretic mobility of membranes but did not take into account the low pH phase behavior and chemical stability of cardiolipin. Here we used 31P NMR to show that in the physiologically relevant membrane phospholipid environment, cardiolipin carries two negative charges at physiological pH. We additionally demonstrate the pH dependent phase behavior and chemical stability of cardiolipin containing membranes.
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Affiliation(s)
- E E Kooijman
- Department of Biological Sciences, Kent State University, Kent, OH, United States.
| | - L A Swim
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Z T Graber
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, United States
| | - Y Y Tyurina
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - H Bayır
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - V E Kagan
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, United States
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Janer A, Prudent J, Paupe V, Fahiminiya S, Majewski J, Sgarioto N, Des Rosiers C, Forest A, Lin ZY, Gingras AC, Mitchell G, McBride HM, Shoubridge EA. SLC25A46 is required for mitochondrial lipid homeostasis and cristae maintenance and is responsible for Leigh syndrome. EMBO Mol Med 2016; 8:1019-38. [PMID: 27390132 PMCID: PMC5009808 DOI: 10.15252/emmm.201506159] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondria form a dynamic network that responds to physiological signals and metabolic stresses by altering the balance between fusion and fission. Mitochondrial fusion is orchestrated by conserved GTPases MFN1/2 and OPA1, a process coordinated in yeast by Ugo1, a mitochondrial metabolite carrier family protein. We uncovered a homozygous missense mutation in SLC25A46, the mammalian orthologue of Ugo1, in a subject with Leigh syndrome. SLC25A46 is an integral outer membrane protein that interacts with MFN2, OPA1, and the mitochondrial contact site and cristae organizing system (MICOS) complex. The subject mutation destabilizes the protein, leading to mitochondrial hyperfusion, alterations in endoplasmic reticulum (ER) morphology, impaired cellular respiration, and premature cellular senescence. The MICOS complex is disrupted in subject fibroblasts, resulting in strikingly abnormal mitochondrial architecture, with markedly shortened cristae. SLC25A46 also interacts with the ER membrane protein complex EMC, and phospholipid composition is altered in subject mitochondria. These results show that SLC25A46 plays a role in a mitochondrial/ER pathway that facilitates lipid transfer, and link altered mitochondrial dynamics to early‐onset neurodegenerative disease and cell fate decisions.
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Affiliation(s)
- Alexandre Janer
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Julien Prudent
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Vincent Paupe
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | | | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Nicolas Sgarioto
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Christine Des Rosiers
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada Research Centre, Montreal Heart Institute, Montreal, QC, Canada
| | - Anik Forest
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada Research Centre, Montreal Heart Institute, Montreal, QC, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Grant Mitchell
- Division of Medical Genetics, Department of Pediatrics, CHU Sainte-Justine and Université de Montréal, Montreal, QC, Canada
| | - Heidi M McBride
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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45
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Lindahl PA, Moore MJ. Labile Low-Molecular-Mass Metal Complexes in Mitochondria: Trials and Tribulations of a Burgeoning Field. Biochemistry 2016; 55:4140-53. [PMID: 27433847 DOI: 10.1021/acs.biochem.6b00216] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Iron, copper, zinc, manganese, cobalt, and molybdenum play important roles in mitochondrial biochemistry, serving to help catalyze reactions in numerous metalloenzymes. These metals are also found in labile "pools" within mitochondria. Although the composition and cellular function of these pools are largely unknown, they are thought to be comprised of nonproteinaceous low-molecular-mass (LMM) metal complexes. Many problems must be solved before these pools can be fully defined, especially problems stemming from the lability of such complexes. This lability arises from inherently weak coordinate bonds between ligands and metals. This is an advantage for catalysis and trafficking, but it makes characterization difficult. The most popular strategy for investigating such pools is to detect them using chelator probes with fluorescent properties that change upon metal coordination. Characterization is limited because of the inevitable destruction of the complexes during their detection. Moreover, probes likely react with more than one type of metal complex, confusing analyses. An alternative approach is to use liquid chromatography (LC) coupled with inductively coupled plasma mass spectrometry (ICP-MS). With help from a previous lab member, the authors recently developed an LC-ICP-MS approach to analyze LMM extracts from yeast and mammalian mitochondria. They detected several metal complexes, including Fe580, Fe1100, Fe1500, Cu5000, Zn1200, Zn1500, Mn1100, Mn2000, Co1200, Co1500, and Mo780 (numbers refer to approximate masses in daltons). Many of these may be used to metalate apo-metalloproteins as they fold inside the organelle. The LC-based approach also has challenges, e.g., in distinguishing artifactual metal complexes from endogenous ones, due to the fact that cells must be disrupted to form extracts before they are passed through chromatography columns prior to analysis. Ultimately, both approaches will be needed to characterize these intriguing complexes and to elucidate their roles in mitochondrial biochemistry.
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Affiliation(s)
- Paul A Lindahl
- Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States.,Department of Biochemistry and Biophysics, Texas A&M University , College Station, Texas 77843-2128, United States
| | - Michael J Moore
- Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States
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Saidijam M, Azizpour S, Patching SG. Amino acid composition analysis of human secondary transport proteins and implications for reliable membrane topology prediction. J Biomol Struct Dyn 2016; 35:929-949. [PMID: 27159787 DOI: 10.1080/07391102.2016.1167622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Secondary transporters in humans are a large group of proteins that transport a wide range of ions, metals, organic and inorganic solutes involved in energy transduction, control of membrane potential and osmotic balance, metabolic processes and in the absorption or efflux of drugs and xenobiotics. They are also emerging as important targets for development of new drugs and as target sites for drug delivery to specific organs or tissues. We have performed amino acid composition (AAC) and phylogenetic analyses and membrane topology predictions for 336 human secondary transport proteins and used the results to confirm protein classification and to look for trends and correlations with structural domains and specific substrates and/or function. Some proteins showed statistically high contents of individual amino acids or of groups of amino acids with similar physicochemical properties. One recurring trend was a correlation between high contents of charged and/or polar residues with misleading results in predictions of membrane topology, which was especially prevalent in Mitochondrial Carrier family proteins. We demonstrate how charged or polar residues located in the middle of transmembrane helices can interfere with their identification by membrane topology tools resulting in missed helices in the prediction. Comparison of AAC in the human proteins with that in 235 secondary transport proteins from Escherichia coli revealed similar overall trends along with differences in average contents for some individual amino acids and groups of similar amino acids that are presumed to result from a greater number of functions and complexity in the higher organism.
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Affiliation(s)
- Massoud Saidijam
- a Department of Molecular Medicine and Genetics, Research Centre for Molecular Medicine, School of Medicine , Hamadan University of Medical Sciences , Hamadan , Iran
| | - Sonia Azizpour
- a Department of Molecular Medicine and Genetics, Research Centre for Molecular Medicine, School of Medicine , Hamadan University of Medical Sciences , Hamadan , Iran
| | - Simon G Patching
- b School of BioMedical Sciences and the Astbury Centre for Structural Molecular Biology , University of Leeds , Leeds LS2 9JT , UK
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Loss of Muscle MTCH2 Increases Whole-Body Energy Utilization and Protects from Diet-Induced Obesity. Cell Rep 2016; 14:1602-1610. [PMID: 26876167 DOI: 10.1016/j.celrep.2016.01.046] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 12/01/2015] [Accepted: 01/13/2016] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial carrier homolog 2 (MTCH2) is a repressor of mitochondrial oxidative phosphorylation (OXPHOS), and its locus is associated with increased BMI in humans. Here, we demonstrate that mice deficient in muscle MTCH2 are protected from diet-induced obesity and hyperinsulinemia and that they demonstrate increased energy expenditure. Deletion of muscle MTCH2 also increases mitochondrial OXPHOS and mass, triggers conversion from glycolytic to oxidative fibers, increases capacity for endurance exercise, and increases heart function. Moreover, metabolic profiling of mice deficient in muscle MTCH2 reveals a preference for carbohydrate utilization and an increase in mitochondria and glycolytic flux in muscles. Thus, MTCH2 is a critical player in muscle biology, modulating metabolism and mitochondria mass as well as impacting whole-body energy homeostasis.
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Wolff NA, Garrick LM, Zhao L, Garrick MD, Thévenod F. Mitochondria represent another locale for the divalent metal transporter 1 (DMT1). Channels (Austin) 2015; 8:458-66. [PMID: 25483589 DOI: 10.4161/19336950.2014.956564] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The divalent metal transporter (DMT1) is well known for its roles in duodenal iron absorption across the apical enterocyte membrane, in iron efflux from the endosome during transferrin-dependent cellular iron acquisition, as well as in uptake of non-transferrin bound iron in many cells. Recently, using multiple approaches, we have obtained evidence that the mitochondrial outer membrane is another subcellular locale of DMT1 expression. While iron is of vital importance for mitochondrial energy metabolism, its delivery is likely to be tightly controlled due to iron's damaging redox properties. Here we provide additional support for a role of DMT1 in mitochondrial iron acquisition by immunofluorescence colocalization with mitochondrial markers in cells and isolated mitochondria, as well as flow cytometric quantification of DMT1-positive mitochondria from an inducible expression system. Physiological consequences of mitochondrial DMT1 expression are discussed also in consideration of other DMT1 substrates, such as manganese, relevant to mitochondrial antioxidant defense.
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Key Words
- AIF, apoptosis-inducing factor
- BSA, bovine serum albumin
- CHO, Chinese hamster ovary
- COXII, cytochrome C oxidase subunit II
- DMT1, divalent metal transporter 1
- HEK293, human embryonic kidney cells
- IRE, iron responsive element
- Lamp1, lysosome-associated membrane protein 1
- MRB, Mitochondrial Resuspending Buffer
- OMM, outer mitochondrial membrane
- PBS, phosphate-buffered saline
- Tf, transferrin
- Tom6/Tom20, translocase of the outer mitochondrial membrane 6 kDa subunit homolog/20 kDa subunit, respectively
- VDAC1, voltage-dependent anion-selective channel protein 1
- divalent metal transporter 1 (DMT1)
- flow cytometry
- immunofluorescence microscopy
- iron transport
- mitochondrial outer membrane
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Affiliation(s)
- Natascha A Wolff
- a Institute of Physiology; Pathophysiology & Toxicology ; University of Witten/Herdecke ; Witten , Germany
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Evidence that the Entamoeba histolytica Mitochondrial Carrier Family Links Mitosomal and Cytosolic Pathways through Exchange of 3'-Phosphoadenosine 5'-Phosphosulfate and ATP. EUKARYOTIC CELL 2015; 14:1144-50. [PMID: 26385892 PMCID: PMC4621310 DOI: 10.1128/ec.00130-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022]
Abstract
Entamoeba histolytica, a microaerophilic protozoan parasite, possesses mitosomes. Mitosomes are mitochondrion-related organelles that have largely lost typical mitochondrial functions, such as those involved in the tricarboxylic acid cycle and oxidative phosphorylation. The biological roles of Entamoeba mitosomes have been a long-standing enigma. We previously demonstrated that sulfate activation, which is not generally compartmentalized to mitochondria, is a major function of E. histolytica mitosomes. Sulfate activation cooperates with cytosolic enzymes, i.e., sulfotransferases (SULTs), for the synthesis of sulfolipids, one of which is cholesteryl sulfate. Notably, cholesteryl sulfate plays an important role in encystation, an essential process in the Entamoeba life cycle. These findings identified a biological role for Entamoeba mitosomes; however, they simultaneously raised a new issue concerning how the reactions of the pathway, separated by the mitosomal membranes, cooperate. Here, we demonstrated that the E. histolytica mitochondrial carrier family (EhMCF) has the capacity to exchange 3'-phosphoadenosine 5'-phosphosulfate (PAPS) with ATP. We also confirmed the cytosolic localization of all the E. histolytica SULTs, suggesting that in Entamoeba, PAPS, which is produced through mitosomal sulfate activation, is translocated to the cytosol and becomes a substrate for SULTs. In contrast, ATP, which is produced through cytosolic pathways, is translocated into the mitosomes and is a necessary substrate for sulfate activation. Taking our findings collectively, we suggest that EhMCF functions as a PAPS/ATP antiporter and plays a crucial role in linking the mitosomal sulfate activation pathway to cytosolic SULTs for the production of sulfolipids.
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50
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Substrate-modulated ADP/ATP-transporter dynamics revealed by NMR relaxation dispersion. Nat Struct Mol Biol 2015; 22:636-41. [PMID: 26167881 PMCID: PMC4527935 DOI: 10.1038/nsmb.3059] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 06/16/2015] [Indexed: 12/02/2022]
Abstract
The ADP/ATP carrier (AAC) transports ADP and ATP across the inner mitochondrial membrane. Unlike most transporters that have 2-fold direct or inverted quasi-symmetry, AAC has the apparent 3-fold rotational symmetry. Further, its transport rate is fast for transporters that carry large solutes. Here, we perform comprehensive NMR relaxation dispersion measurements for the yeast AAC carrier 3, which provide residue-specific information on the protein conformational exchange. Our data indicate that AAC is predominantly in the cytosol-facing open state and converts to a lowly populated state in an asymmetric manner despite its three-fold structural symmetry. Binding of the substrate ADP significantly increases the rate of conformational exchange, whereas the inhibitor CATR slows the exchange. These results suggest that while the transporter catalyzes the translocation of substrate, the substrate also facilitates interconversion between alternating states that may be relevant to the transport function.
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