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Del Castillo J, Tool ATJ, van Leeuwen K, van Alphen FPJ, Brands MM, Suijker MH, Meijer AB, Hoogendijk AJ, Kuijpers TW. Platelet proteomic profiling in sitosterolemia suggests thrombocytopenia is driven by lipid disorder and not platelet aberrations. Blood Adv 2024; 8:2466-2477. [PMID: 38513134 PMCID: PMC11112606 DOI: 10.1182/bloodadvances.2023012018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/23/2024] Open
Abstract
ABSTRACT Sitosterolemia is a rare autosomal recessive genetic disorder in which patients develop hypercholesterolemia and may exhibit abnormal hematologic and/or liver test results. In this disease, dysfunction of either ABCG5 or ABCG8 results in the intestinal hyperabsorption of all sterols, including cholesterol and, more specifically, plant sterols or xenosterols, as well as in the impaired ability to excrete xenosterols into the bile. It remains unknown how and why some patients develop hematologic abnormalities. Only a few unrelated patients with hematologic abnormalities at the time of diagnosis have been reported. Here, we report on 2 unrelated pedigrees who were believed to have chronic immune thrombocytopenia as their most prominent feature. Both consanguineous families showed recessive gene variants in ABCG5, which were associated with the disease by in silico protein structure analysis and clinical segregation. Hepatosplenomegaly was absent. Thrombopoietin levels and megakaryocyte numbers in the bone marrow were normal. Metabolic analysis confirmed the presence of strongly elevated plasma levels of xenosterols. Potential platelet proteomic aberrations were longitudinally assessed following dietary restrictions combined with administration of the sterol absorption inhibitor ezetimibe. No significant effects on platelet protein content before and after the onset of treatment were demonstrated. Although we cannot exclude that lipotoxicity has a direct and platelet-specific impact in patients with sitosterolemia, our data suggest that thrombocytopenia is neither caused by a lack of megakaryocytes nor driven by proteomic aberrations in the platelets themselves.
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Affiliation(s)
- Jessica Del Castillo
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Anton T. J. Tool
- Department of Blood Cell Research, Sanquin Research, Amsterdam, The Netherlands
| | - Karin van Leeuwen
- Department of Research Facilities, Sanquin Research, Amsterdam, The Netherlands
| | | | - Marion M. Brands
- Department of Pediatric Metabolic Diseases, Emma Children’s Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Monique H. Suijker
- Department of Pediatric Hematology, Emma Children’s Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alexander B. Meijer
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Arie J. Hoogendijk
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Taco W. Kuijpers
- Department of Blood Cell Research, Sanquin Research, Amsterdam, The Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children’s Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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2
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Rostovtseva TK, Weinrich M, Jacobs D, Rosencrans WM, Bezrukov SM. Dimeric Tubulin Modifies Mechanical Properties of Lipid Bilayer, as Probed Using Gramicidin A Channel. Int J Mol Sci 2024; 25:2204. [PMID: 38396879 PMCID: PMC10889239 DOI: 10.3390/ijms25042204] [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: 12/07/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Using the gramicidin A channel as a molecular probe, we show that tubulin binding to planar lipid membranes changes the channel kinetics-seen as an increase in the lifetime of the channel dimer-and thus points towards modification of the membrane's mechanical properties. The effect is more pronounced in the presence of non-lamellar lipids in the lipid mixture used for membrane formation. To interpret these findings, we propose that tubulin binding redistributes the lateral pressure of lipid packing along the membrane depth, making it closer to the profile expected for lamellar lipids. This redistribution happens because tubulin perturbs the lipid headgroup spacing to reach the membrane's hydrophobic core via its amphiphilic α-helical domain. Specifically, it increases the forces of repulsion between the lipid headgroups and reduces such forces in the hydrophobic region. We suggest that the effect is reciprocal, meaning that alterations in lipid bilayer mechanics caused by membrane remodeling during cell proliferation in disease and development may also modulate tubulin membrane binding, thus exerting regulatory functions. One of those functions includes the regulation of protein-protein interactions at the membrane surface, as exemplified by VDAC complexation with tubulin.
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Affiliation(s)
- Tatiana K. Rostovtseva
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
| | - Michael Weinrich
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Daniel Jacobs
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
| | - William M. Rosencrans
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sergey M. Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
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3
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Nestorovich EM, Bezrukov SM. Beta-Barrel Channel Response to High Electric Fields: Functional Gating or Reversible Denaturation? Int J Mol Sci 2023; 24:16655. [PMID: 38068977 PMCID: PMC10706840 DOI: 10.3390/ijms242316655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/16/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Ion channels exhibit gating behavior, fluctuating between open and closed states, with the transmembrane voltage serving as one of the essential regulators of this process. Voltage gating is a fundamental functional aspect underlying the regulation of ion-selective, mostly α-helical, channels primarily found in excitable cell membranes. In contrast, there exists another group of larger, and less selective, β-barrel channels of a different origin, which are not directly associated with cell excitability. Remarkably, these channels can also undergo closing, or "gating", induced by sufficiently strong electric fields. Once the field is removed, the channels reopen, preserving a memory of the gating process. In this study, we explored the hypothesis that the voltage-induced closure of the β-barrel channels can be seen as a form of reversible protein denaturation by the high electric fields applied in model membranes experiments-typically exceeding twenty million volts per meter-rather than a manifestation of functional gating. Here, we focused on the bacterial outer membrane channel OmpF reconstituted into planar lipid bilayers and analyzed various characteristics of the closing-opening process that support this idea. Specifically, we considered the nearly symmetric response to voltages of both polarities, the presence of multiple closed states, the stabilization of the open conformation in channel clusters, the long-term gating memory, and the Hofmeister effects in closing kinetics. Furthermore, we contemplate the evolutionary aspect of the phenomenon, proposing that the field-induced denaturation of membrane proteins might have served as a starting point for their development into amazing molecular machines such as voltage-gated channels of nerve and muscle cells.
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Affiliation(s)
- Ekaterina M. Nestorovich
- Department of Biology, The Catholic University of America, Washington, DC 20064, USA
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Sergey M. Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA;
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4
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Chen Z, Jasinska W, Ashraf M, Rosental L, Hong J, Zhang D, Brotman Y, Shi J. Lipidomic insights into the response of Arabidopsis sepals to mild heat stress. ABIOTECH 2023; 4:224-237. [PMID: 37970465 PMCID: PMC10638258 DOI: 10.1007/s42994-023-00103-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/03/2023] [Indexed: 11/17/2023]
Abstract
Arabidopsis sepals coordinate flower opening in the morning as ambient temperature rises; however, the underlying molecular mechanisms are poorly understood. Mutation of one heat shock protein encoding gene, HSP70-16, impaired sepal heat stress responses (HSR), disrupting lipid metabolism, especially sepal cuticular lipids, leading to abnormal flower opening. To further explore, to what extent, lipids play roles in this process, in this study, we compared lipidomic changes in sepals of hsp70-16 and vdac3 (mutant of a voltage-dependent anion channel, VDAC3, an HSP70-16 interactor) grown under both normal (22 °C) and mild heat stress (27 °C, mild HS) temperatures. Under normal temperature, neither hsp70-16 nor vdac3 sepals showed significant changes in total lipids; however, vdac3 but not hsp70-16 sepals exhibited significant reductions in the ratios of all detected 11 lipid classes, except the monogalactosyldiacylglycerols (MGDGs). Under mild HS temperature, hsp70-16 but not vdac3 sepals showed dramatic reduction in total lipids. In addition, vdac3 sepals exhibited a significant accumulation of plastidic lipids, especially sulfoquinovosyldiacylglycerols (SQDGs) and phosphatidylglycerols (PGs), whereas hsp70-16 sepals had a significant accumulation of triacylglycerols (TAGs) and simultaneous dramatic reductions in SQDGs and phospholipids (PLs), such as phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), and phosphatidylserines (PSs). These findings revealed that the impact of mild HS on sepal lipidome is influenced by genetic factors, and further, that HSP70-16 and VDAC3 differently affect sepal lipidomic responses to mild HS. Our studies provide a lipidomic insight into functions of HSP and VDAC proteins in the plant's HSR, in the context of floral development. Supplementary Information The online version contains supplementary material available at 10.1007/s42994-023-00103-x.
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Affiliation(s)
- Zican Chen
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Weronika Jasinska
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, 84105 Israel
| | - Muhammad Ashraf
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Leah Rosental
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, 84105 Israel
| | - Jung Hong
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA 5064 Australia
- Yazhou Bay Institute of Deepsea Sci-Tech, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Yariv Brotman
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, 84105 Israel
| | - Jianxin Shi
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240 China
- Yazhou Bay Institute of Deepsea Sci-Tech, Shanghai Jiao Tong University, Shanghai, 200240 China
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5
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Ngo VA, Queralt-Martín M, Khan F, Bergdoll L, Abramson J, Bezrukov SM, Rostovtseva TK, Hoogerheide DP, Noskov SY. The Single Residue K12 Governs the Exceptional Voltage Sensitivity of Mitochondrial Voltage-Dependent Anion Channel Gating. J Am Chem Soc 2022; 144:14564-14577. [PMID: 35925797 DOI: 10.1021/jacs.2c03316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The voltage-dependent anion channel (VDAC) is a β-barrel channel of the mitochondrial outer membrane (MOM) that passively transports ions, metabolites, polypeptides, and single-stranded DNA. VDAC responds to a transmembrane potential by "gating," i.e. transitioning to one of a variety of low-conducting states of unknown structure. The gated state results in nearly complete suppression of multivalent mitochondrial metabolite (such as ATP and ADP) transport, while enhancing calcium transport. Voltage gating is a universal property of β-barrel channels, but VDAC gating is anomalously sensitive to transmembrane potential. Here, we show that a single residue in the pore interior, K12, is responsible for most of VDAC's voltage sensitivity. Using the analysis of over 40 μs of atomistic molecular dynamics (MD) simulations, we explore correlations between motions of charged residues inside the VDAC pore and geometric deformations of the β-barrel. Residue K12 is bistable; its motions between two widely separated positions along the pore axis enhance the fluctuations of the β-barrel and augment the likelihood of gating. Single channel electrophysiology of various K12 mutants reveals a dramatic reduction of the voltage-induced gating transitions. The crystal structure of the K12E mutant at a resolution of 2.6 Å indicates a similar architecture of the K12E mutant to the wild type; however, 60 μs of atomistic MD simulations using the K12E mutant show restricted motion of residue 12, due to enhanced connectivity with neighboring residues, and diminished amplitude of barrel motions. We conclude that β-barrel fluctuations, governed particularly by residue K12, drive VDAC gating transitions.
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Affiliation(s)
- Van A Ngo
- Center for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada.,Advanced Computing for Life Sciences and Engineering, Computing and Computational Sciences, National Center for Computational Sciences, Oak Ridge National Lab, Oak Ridge, Tennessee 37830, United States
| | - María Queralt-Martín
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States.,Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071 Castellón, Spain
| | - Farha Khan
- Department of Physiology, University of California, Los Angeles, California 90095, United States
| | - Lucie Bergdoll
- LISM UMR 7255, CNRS and Aix-Marseille University, Marseille cedex 20, 13402, France
| | - Jeff Abramson
- Department of Physiology, University of California, Los Angeles, California 90095, United States
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sergei Yu Noskov
- Center for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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6
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Rajendran M, Queralt-Martín M, Gurnev PA, Rosencrans WM, Rovini A, Jacobs D, Abrantes K, Hoogerheide DP, Bezrukov SM, Rostovtseva TK. Restricting α-synuclein transport into mitochondria by inhibition of α-synuclein-VDAC complexation as a potential therapeutic target for Parkinson's disease treatment. Cell Mol Life Sci 2022; 79:368. [PMID: 35718804 PMCID: PMC11072225 DOI: 10.1007/s00018-022-04389-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/13/2022] [Accepted: 05/20/2022] [Indexed: 11/03/2022]
Abstract
Involvement of alpha-synuclein (αSyn) in Parkinson's disease (PD) is complicated and difficult to trace on cellular and molecular levels. Recently, we established that αSyn can regulate mitochondrial function by voltage-activated complexation with the voltage-dependent anion channel (VDAC) on the mitochondrial outer membrane. When complexed with αSyn, the VDAC pore is partially blocked, reducing the transport of ATP/ADP and other metabolites. Further, αSyn can translocate into the mitochondria through VDAC, where it interferes with mitochondrial respiration. Recruitment of αSyn to the VDAC-containing lipid membrane appears to be a crucial prerequisite for both the blockage and translocation processes. Here we report an inhibitory effect of HK2p, a small membrane-binding peptide from the mitochondria-targeting N-terminus of hexokinase 2, on αSyn membrane binding, and hence on αSyn complex formation with VDAC and translocation through it. In electrophysiology experiments, the addition of HK2p at micromolar concentrations to the same side of the membrane as αSyn results in a dramatic reduction of the frequency of blockage events in a concentration-dependent manner, reporting on complexation inhibition. Using two complementary methods of measuring protein-membrane binding, bilayer overtone analysis and fluorescence correlation spectroscopy, we found that HK2p induces detachment of αSyn from lipid membranes. Experiments with HeLa cells using proximity ligation assay confirmed that HK2p impedes αSyn entry into mitochondria. Our results demonstrate that it is possible to regulate αSyn-VDAC complexation by a rationally designed peptide, thus suggesting new avenues in the search for peptide therapeutics to alleviate αSyn mitochondrial toxicity in PD and other synucleinopathies.
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Affiliation(s)
- Megha Rajendran
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - María Queralt-Martín
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, Castellón, 12071, Spain
| | - Philip A Gurnev
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - William M Rosencrans
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Amandine Rovini
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Daniel Jacobs
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Kaitlin Abrantes
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Sergey M Bezrukov
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Tatiana K Rostovtseva
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA.
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7
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Altabella T, Ramirez-Estrada K, Ferrer A. Phytosterol metabolism in plant positive-strand RNA virus replication. PLANT CELL REPORTS 2022; 41:281-291. [PMID: 34665312 DOI: 10.1007/s00299-021-02799-x] [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: 06/19/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
The genome of most plant viruses consists of a single positive-strand of RNA (+ ssRNA). Successful replication of these viruses is fully dependent on the endomembrane system of the infected cells, which experiences a massive proliferation and a profound reshaping that enables assembly of the macromolecular complexes where virus genome replication occurs. Assembly of these viral replicase complexes (VRCs) requires a highly orchestrated interplay of multiple virus and co-opted host cell factors to create an optimal microenvironment for efficient assembly and functioning of the virus genome replication machinery. It is now widely accepted that VRC formation involves the recruitment of high levels of sterols, but the specific role of these essential components of cell membranes and the precise molecular mechanisms underlying sterol enrichment at VRCs are still poorly known. In this review, we intend to summarize the most relevant knowledge on the role of sterols in ( +)ssRNA virus replication and discuss the potential of manipulating the plant sterol pathway to help plants fight these infectious agents.
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Affiliation(s)
- Teresa Altabella
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Cerdanyola, 08193, Barcelona, Spain.
- Department of Biology, Healthcare and the Environment, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028, Barcelona, Spain.
| | - Karla Ramirez-Estrada
- Laboratory of Cell Metabolism, Faculty of Chemistry, Autonomous University of Nuevo León, San Nicolás de los Garza, NL, 66451, México
| | - Albert Ferrer
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Cerdanyola, 08193, Barcelona, Spain.
- Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028, Barcelona, Spain.
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8
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Jethva J, Schmidt RR, Sauter M, Selinski J. Try or Die: Dynamics of Plant Respiration and How to Survive Low Oxygen Conditions. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11020205. [PMID: 35050092 PMCID: PMC8780655 DOI: 10.3390/plants11020205] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 05/09/2023]
Abstract
Fluctuations in oxygen (O2) availability occur as a result of flooding, which is periodically encountered by terrestrial plants. Plant respiration and mitochondrial energy generation rely on O2 availability. Therefore, decreased O2 concentrations severely affect mitochondrial function. Low O2 concentrations (hypoxia) induce cellular stress due to decreased ATP production, depletion of energy reserves and accumulation of metabolic intermediates. In addition, the transition from low to high O2 in combination with light changes-as experienced during re-oxygenation-leads to the excess formation of reactive oxygen species (ROS). In this review, we will update our current knowledge about the mechanisms enabling plants to adapt to low-O2 environments, and how to survive re-oxygenation. New insights into the role of mitochondrial retrograde signaling, chromatin modification, as well as moonlighting proteins and mitochondrial alternative electron transport pathways (and their contribution to low O2 tolerance and survival of re-oxygenation), are presented.
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Affiliation(s)
- Jay Jethva
- Department of Plant Developmental Biology and Plant Physiology, Faculty of Mathematics and Natural Sciences, Botanical Institute, Christian-Albrechts University, D-24118 Kiel, Germany; (J.J.); (M.S.)
| | - Romy R. Schmidt
- Department of Plant Biotechnology, Faculty of Biology, University of Bielefeld, D-33615 Bielefeld, Germany;
| | - Margret Sauter
- Department of Plant Developmental Biology and Plant Physiology, Faculty of Mathematics and Natural Sciences, Botanical Institute, Christian-Albrechts University, D-24118 Kiel, Germany; (J.J.); (M.S.)
| | - Jennifer Selinski
- Department of Plant Cell Biology, Botanical Institute, Faculty of Mathematics and Natural Sciences, Christian-Albrechts University, D-24118 Kiel, Germany
- Correspondence: ; Tel.: +49-(0)431-880-4245
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9
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Lapshin NK, Piotrovskii MS, Trofimova MS. Sterol Extraction from Isolated Plant Plasma Membrane Vesicles Affects H +-ATPase Activity and H +-Transport. Biomolecules 2021; 11:1891. [PMID: 34944535 PMCID: PMC8699270 DOI: 10.3390/biom11121891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Plasma membrane H+-ATPase is known to be detected in detergent-resistant sterol-enriched fractions, also called "raft" domains. Studies on H+-ATPase reconstituted in artificial or native membrane vesicles have shown both sterol-mediated stimulations and inhibitions of its activity. Here, using sealed isolated plasma membrane vesicles, we investigated the effects of sterol depletion in the presence of methyl-β-cyclodextrin (MβCD) on H+-ATPase activity. The rate of ATP-dependent ∆µH+ generation and the kinetic parameters of ATP hydrolysis were evaluated. We show that the relative sterols content in membrane vesicles decreased gradually after treatment with MβCD and reached approximately 40% of their initial level in 30 mM probe solution. However, changes in the hydrolytic and H+-transport activities of the enzyme were nonlinear. The extraction of up to 20% of the initial sterols was accompanied by strong stimulation of ATP-dependent H+-transport in comparison with the hydrolytic activity of enzymes. Further sterol depletion led to a significant inhibition of active proton transport with an increase in passive H+-leakage. The solubilization of control and sterol-depleted vesicles in the presence of dodecyl maltoside negated the differences in the kinetics parameters of ATP hydrolysis, and all samples demonstrated maximal hydrolytic activities. The mechanisms behind the sensitivity of ATP-dependent H+-transport to sterols in the lipid environment of plasma membrane H+-ATPase are discussed.
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Affiliation(s)
| | | | - Marina S. Trofimova
- K.A. Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences (IPP RAS), 35 Botanicheskaya St., 127276 Moscow, Russia; (N.K.L.); (M.S.P.)
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10
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Hoogerheide DP, Gurnev PA, Rostovtseva TK, Bezrukov SM. Voltage-activated complexation of α-synuclein with three diverse β-barrel channels: VDAC, MspA, and α-hemolysin. Proteomics 2021; 22:e2100060. [PMID: 34813679 DOI: 10.1002/pmic.202100060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 01/07/2023]
Abstract
Voltage-activated complexation is the process by which a transmembrane potential drives complex formation between a membrane-embedded channel and a soluble or membrane-peripheral target protein. Metabolite and calcium flux across the mitochondrial outer membrane was shown to be regulated by voltage-activated complexation of the voltage-dependent anion channel (VDAC) and either dimeric tubulin or α-synuclein (αSyn). However, the roles played by VDAC's characteristic attributes-its anion selectivity and voltage gating behavior-have remained unclear. Here, we compare in vitro measurements of voltage-activated complexation of αSyn with three well-characterized β-barrel channels-VDAC, MspA, and α-hemolysin-that differ widely in their organism of origin, structure, geometry, charge density distribution, and voltage gating behavior. The voltage dependences of the complexation dynamics for the different channels are observed to differ quantitatively but have similar qualitative features. In each case, energy landscape modeling describes the complexation dynamics in a manner consistent with the known properties of the individual channels, while voltage gating does not appear to play a role. The reaction free energy landscapes thus calculated reveal a non-trivial dependence of the αSyn/channel complex stability on the surface density of αSyn.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Philip A Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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11
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Ashraf M, Mao Q, Hong J, Shi L, Ran X, Liaquat F, Uzair M, Liang W, Fernie AR, Shi J. HSP70-16 and VDAC3 jointly inhibit seed germination under cold stress in Arabidopsis. PLANT, CELL & ENVIRONMENT 2021; 44:3616-3627. [PMID: 34173257 DOI: 10.1111/pce.14138] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/09/2021] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Abscisic acid (ABA) transport plays a crucial role in seed germination under unfavourable conditions such as cold stress. Both heat shock protein 70 (HSP70) and voltage-dependent anion channel (VDAC) protein are involved in cold stress responses in Arabidopsis. However, their roles in seed germination with regard to ABA signaling remain unknown. Here we demonstrated that Arabidopsis HSP70-16 and VDAC3 jointly suppress seed germination under cold stress conditions. At 4°C, both HSP70-16 and VDAC3 facilitated the efflux of ABA from the endosperm to the embryo and thus inhibited seed germination. HSP70-16 interacted with VDAC3 on the plasma membrane and in the nucleus, and the interplay between HSP70-16 and VDAC3 activated the opening of the VDAC3 ion channel. Our work established a novel function of HSP70-16 in seed germination under cold stress and a possible association of VDAC3 activity with ABA transportation from endosperm to embryo under cold stress conditions. This study reveals that HSP70-16 interacts with VDAC3 and facilitates the opening of the VDAC3 ion channel, which influences ABA efflux from endosperm to embryo, thus negatively regulates seed germination under cold stress.
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Affiliation(s)
- Muhammad Ashraf
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qionglei Mao
- CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jun Hong
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Shi
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoruo Ran
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Fiza Liaquat
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Muhammad Uzair
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Alisdair R Fernie
- Department of Molecular Physiology, Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Jianxin Shi
- Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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12
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Benz R. Historical Perspective of Pore-Forming Activity Studies of Voltage-Dependent Anion Channel (Eukaryotic or Mitochondrial Porin) Since Its Discovery in the 70th of the Last Century. Front Physiol 2021; 12:734226. [PMID: 35547863 PMCID: PMC9083909 DOI: 10.3389/fphys.2021.734226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/24/2021] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic porin, also known as Voltage-Dependent Anion Channel (VDAC), is the most frequent protein in the outer membrane of mitochondria that are responsible for cellular respiration. Mitochondria are most likely descendants of strictly aerobic Gram-negative bacteria from the α-proteobacterial lineage. In accordance with the presumed ancestor, mitochondria are surrounded by two membranes. The mitochondrial outer membrane contains besides the eukaryotic porins responsible for its major permeability properties a variety of other not fully identified channels. It encloses also the TOM apparatus together with the sorting mechanism SAM, responsible for the uptake and assembly of many mitochondrial proteins that are encoded in the nucleus and synthesized in the cytoplasm at free ribosomes. The recognition and the study of electrophysiological properties of eukaryotic porin or VDAC started in the late seventies of the last century by a study of Schein et al., who reconstituted the pore from crude extracts of Paramecium mitochondria into planar lipid bilayer membranes. Whereas the literature about structure and function of eukaryotic porins was comparatively rare during the first 10years after the first study, the number of publications started to explode with the first sequencing of human Porin 31HL and the recognition of the important function of eukaryotic porins in mitochondrial metabolism. Many genomes contain more than one gene coding for homologs of eukaryotic porins. More than 100 sequences of eukaryotic porins are known to date. Although the sequence identity between them is relatively low, the polypeptide length and in particular, the electrophysiological characteristics are highly preserved. This means that all eukaryotic porins studied to date are anion selective in the open state. They are voltage-dependent and switch into cation-selective substates at voltages in the physiological relevant range. A major breakthrough was also the elucidation of the 3D structure of the eukaryotic pore, which is formed by 19 β-strands similar to those of bacterial porin channels. The function of the presumed gate an α-helical stretch of 20 amino acids allowed further studies with respect to voltage dependence and function, but its exact role in channel gating is still not fully understood.
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13
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Hoogerheide DP, Rostovtseva TK, Bezrukov SM. Exploring lipid-dependent conformations of membrane-bound α-synuclein with the VDAC nanopore. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183643. [PMID: 33971161 PMCID: PMC8255272 DOI: 10.1016/j.bbamem.2021.183643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023]
Abstract
Regulation of VDAC by α-synuclein (αSyn) is a rich and instructive example of protein-protein interactions catalyzed by a lipid membrane surface. αSyn, a peripheral membrane protein involved in Parkinson's disease pathology, is known to bind to membranes in a transient manner. αSyn's negatively charged C-terminal domain is then available to be electromechanically trapped by the VDAC β-barrel, a process that is observed in vitro as the reversible reduction of ion flow through a single voltage-biased VDAC nanopore. Binding of αSyn to the lipid bilayer is a prerequisite of the channel-protein interaction; surprisingly, however, we find that the strength of αSyn binding to the membrane does not correlate in any simple way with its efficiency of blocking VDAC, suggesting that the lipid-dependent conformations of the membrane-bound αSyn control the interaction. Quantitative models of the free energy landscape governing the capture and release processes allow us to discriminate between several αSyn (sub-) conformations on the membrane surface. These results, combined with known structural features of αSyn on anionic lipid membranes, point to a model in which the lipid composition determines the fraction of αSyn molecules for which the charged C terminal domain is constrained to be close, but not tightly bound, to the membrane surface and thus readily captured by the VDAC nanopore. We speculate that changes in the mitochondrial membrane lipid composition may be key regulators of the αSyn-VDAC interaction and consequently of VDAC-facilitated transport of ions and metabolites in and out of mitochondria and, i.e. mitochondrial metabolism.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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14
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The Role of Voltage-Dependent Anion Channel in Mitochondrial Dysfunction and Human Disease. Cells 2021; 10:cells10071737. [PMID: 34359907 PMCID: PMC8305817 DOI: 10.3390/cells10071737] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/03/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023] Open
Abstract
The voltage-dependent anion channel (VDAC) is a β-barrel membrane protein located in the outer mitochondrial membrane (OMM). VDAC has two conductance states: an open anion selective state, and a closed and slightly cation-selective state. VDAC conductance states play major roles in regulating permeability of ATP/ADP, regulation of calcium homeostasis, calcium flux within ER-mitochondria contact sites, and apoptotic signaling events. Three reported structures of VDAC provide information on the VDAC open state via X-ray crystallography and nuclear magnetic resonance (NMR). Together, these structures provide insight on how VDAC aids metabolite transport. The interaction partners of VDAC, together with the permeability of the pore, affect the molecular pathology of diseases including Parkinson’s disease (PD), Friedreich’s ataxia (FA), lupus, and cancer. To fully address the molecular role of VDAC in disease pathology, major questions must be answered on the structural conformers of VDAC. For example, further information is needed on the structure of the closed state, how binding partners or membrane potential could lead to the open/closed states, the function and mobility of the N-terminal α-helical domain of VDAC, and the physiological role of VDAC oligomers. This review covers our current understanding of the various states of VDAC, VDAC interaction partners, and the roles they play in mitochondrial regulation pertaining to human diseases.
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15
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Hiser C, Montgomery BL, Ferguson-Miller S. TSPO protein binding partners in bacteria, animals, and plants. J Bioenerg Biomembr 2021; 53:463-487. [PMID: 34191248 PMCID: PMC8243069 DOI: 10.1007/s10863-021-09905-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/12/2021] [Indexed: 12/11/2022]
Abstract
The ancient membrane protein TSPO is phylogenetically widespread from archaea and bacteria to insects, vertebrates, plants, and fungi. TSPO’s primary amino acid sequence is only modestly conserved between diverse species, although its five transmembrane helical structure appears mainly conserved. Its cellular location and orientation in membranes have been reported to vary between species and tissues, with implications for potential diverse binding partners and function. Most TSPO functions relate to stress-induced changes in metabolism, but in many cases it is unclear how TSPO itself functions—whether as a receptor, a sensor, a transporter, or a translocator. Much evidence suggests that TSPO acts indirectly by association with various protein binding partners or with endogenous or exogenous ligands. In this review, we focus on proteins that have most commonly been invoked as TSPO binding partners. We suggest that TSPO was originally a bacterial receptor/stress sensor associated with porphyrin binding as its most ancestral function and that it later developed additional stress-related roles in eukaryotes as its ability to bind new partners evolved.
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Affiliation(s)
- Carrie Hiser
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA. .,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
| | - Beronda L Montgomery
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
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16
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Saidani H, Léonetti M, Kmita H, Homblé F. The Open State Selectivity of the Bean Seed VDAC Depends on Stigmasterol and Ion Concentration. Int J Mol Sci 2021; 22:ijms22063034. [PMID: 33809742 PMCID: PMC8002290 DOI: 10.3390/ijms22063034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 03/12/2021] [Indexed: 11/16/2022] Open
Abstract
The voltage-dependent anion channel (VDAC) is the major pathway for metabolites and ions transport through the mitochondrial outer membrane. It can regulate the flow of solutes by switching to a low conductance state correlated with a selectivity reversal, or by a selectivity inversion of its open state. The later one was observed in non-plant VDACs and is poorly characterized. We aim at investigating the selectivity inversion of the open state using plant VDAC purified from Phaseolus coccineus (PcVDAC) to evaluate its physiological role. Our main findings are: (1) The VDAC selectivity inversion of the open state occurs in PcVDAC, (2) Ion concentration and stigmasterol affect the occurrence of the open state selectivity inversion and stigmasterol appears to interact directly with PcVDAC. Interestingly, electrophysiological data concerning the selectivity inversion of the PcVDAC open state suggests that the phenomenon probably does not have a significant physiological effect in vivo.
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Affiliation(s)
- Hayet Saidani
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Bruxelles, Belgium;
- Laboratory of Functional Neurophysiology and Pathology, Research Unit, UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, 1068 Tunis, Tunisia
| | - Marc Léonetti
- Université de. Grenoble Alpes, CNRS, LRP, 38000 Grenoble, France;
| | - Hanna Kmita
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland;
| | - Fabrice Homblé
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Bruxelles, Belgium;
- Correspondence: ; Tel.: +32-2-650-5383
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17
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Najbauer EE, Becker S, Giller K, Zweckstetter M, Lange A, Steinem C, de Groot BL, Griesinger C, Andreas LB. Structure, gating and interactions of the voltage-dependent anion channel. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:159-172. [PMID: 33782728 PMCID: PMC8071794 DOI: 10.1007/s00249-021-01515-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 02/19/2021] [Accepted: 03/08/2021] [Indexed: 12/14/2022]
Abstract
The voltage-dependent anion channel (VDAC) is one of the most highly abundant proteins found in the outer mitochondrial membrane, and was one of the earliest discovered. Here we review progress in understanding VDAC function with a focus on its structure, discussing various models proposed for voltage gating as well as potential drug targets to modulate the channel's function. In addition, we explore the sensitivity of VDAC structure to variations in the membrane environment, comparing DMPC-only, DMPC with cholesterol, and near-native lipid compositions, and use magic-angle spinning NMR spectroscopy to locate cholesterol on the outside of the β-barrel. We find that the VDAC protein structure remains unchanged in different membrane compositions, including conditions with cholesterol.
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Affiliation(s)
- Eszter E Najbauer
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum Für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut Für Molekulare Pharmakologie, 13125, Berlin, Germany
- Institut Für Biologie, Humboldt-Universität Zu Berlin, 10115, Berlin, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
- Max-Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Bert L de Groot
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Griesinger
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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18
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Rostovtseva TK, Queralt-Martín M, Rosencrans WM, Bezrukov SM. Targeting the Multiple Physiologic Roles of VDAC With Steroids and Hydrophobic Drugs. Front Physiol 2020; 11:446. [PMID: 32457654 PMCID: PMC7221028 DOI: 10.3389/fphys.2020.00446] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/09/2020] [Indexed: 12/12/2022] Open
Abstract
There is accumulating evidence that endogenous steroids and non-polar drugs are involved in the regulation of mitochondrial physiology. Many of these hydrophobic compounds interact with the Voltage Dependent Anion Channel (VDAC). This major metabolite channel in the mitochondrial outer membrane (MOM) regulates the exchange of ions and water-soluble metabolites, such as ATP and ADP, across the MOM, thus governing mitochondrial respiration. Proteomics and biochemical approaches together with molecular dynamics simulations have identified an impressively large number of non-polar compounds, including endogenous, able to bind to VDAC. These findings have sparked speculation that both natural steroids and synthetic hydrophobic drugs regulate mitochondrial physiology by directly affecting VDAC ion channel properties and modulating its metabolite permeability. Here we evaluate recent studies investigating the effect of identified VDAC-binding natural steroids and non-polar drugs on VDAC channel functioning. We argue that while many compounds are found to bind to the VDAC protein, they do not necessarily affect its channel functions in vitro. However, they may modify other aspects of VDAC physiology such as interaction with its cytosolic partner proteins or complex formation with other mitochondrial membrane proteins, thus altering mitochondrial function.
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Affiliation(s)
- Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - María Queralt-Martín
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - William M Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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19
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Kanwar P, Samtani H, Sanyal SK, Srivastava AK, Suprasanna P, Pandey GK. VDAC and its interacting partners in plant and animal systems: an overview. Crit Rev Biotechnol 2020; 40:715-732. [PMID: 32338074 DOI: 10.1080/07388551.2020.1756214] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Molecular trafficking between different subcellular compartments is the key for normal cellular functioning. Voltage-dependent anion channels (VDACs) are small-sized proteins present in the outer mitochondrial membrane, which mediate molecular trafficking between mitochondria and cytoplasm. The conductivity of VDAC is dependent on the transmembrane voltage, its oligomeric state and membrane lipids. VDAC acts as a convergence point to a diverse variety of mitochondrial functions as well as cell survival. This functional diversity is attained due to their interaction with a plethora of proteins inside the cell. Although, there are hints toward functional conservation/divergence between animals and plants; knowledge about the functional role of the VDACs in plants is still limited. We present here a comparative overview to provide an integrative picture of the interactions of VDAC with different proteins in both animals and plants. Also discussed are their physiological functions from the perspective of cellular movements, signal transduction, cellular fate, disease and development. This in-depth knowledge of the biological importance of VDAC and its interacting partner(s) will assist us to explore their function in the applied context in both plant and animal.
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Affiliation(s)
- Poonam Kanwar
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Harsha Samtani
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Sibaji K Sanyal
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Ashish K Srivastava
- Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Penna Suprasanna
- Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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20
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Uzureau S, Lecordier L, Uzureau P, Hennig D, Graversen JH, Homblé F, Mfutu PE, Oliveira Arcolino F, Ramos AR, La Rovere RM, Luyten T, Vermeersch M, Tebabi P, Dieu M, Cuypers B, Deborggraeve S, Rabant M, Legendre C, Moestrup SK, Levtchenko E, Bultynck G, Erneux C, Pérez-Morga D, Pays E. APOL1 C-Terminal Variants May Trigger Kidney Disease through Interference with APOL3 Control of Actomyosin. Cell Rep 2020; 30:3821-3836.e13. [PMID: 32187552 PMCID: PMC7090385 DOI: 10.1016/j.celrep.2020.02.064] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/17/2020] [Accepted: 02/14/2020] [Indexed: 11/18/2022] Open
Abstract
The C-terminal variants G1 and G2 of apolipoprotein L1 (APOL1) confer human resistance to the sleeping sickness parasite Trypanosoma rhodesiense, but they also increase the risk of kidney disease. APOL1 and APOL3 are death-promoting proteins that are partially associated with the endoplasmic reticulum and Golgi membranes. We report that in podocytes, either APOL1 C-terminal helix truncation (APOL1Δ) or APOL3 deletion (APOL3KO) induces similar actomyosin reorganization linked to the inhibition of phosphatidylinositol-4-phosphate [PI(4)P] synthesis by the Golgi PI(4)-kinase IIIB (PI4KB). Both APOL1 and APOL3 can form K+ channels, but only APOL3 exhibits Ca2+-dependent binding of high affinity to neuronal calcium sensor-1 (NCS-1), promoting NCS-1-PI4KB interaction and stimulating PI4KB activity. Alteration of the APOL1 C-terminal helix triggers APOL1 unfolding and increased binding to APOL3, affecting APOL3-NCS-1 interaction. Since the podocytes of G1 and G2 patients exhibit an APOL1Δ or APOL3KO-like phenotype, APOL1 C-terminal variants may induce kidney disease by preventing APOL3 from activating PI4KB, with consecutive actomyosin reorganization of podocytes.
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Affiliation(s)
- Sophie Uzureau
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Laurence Lecordier
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Pierrick Uzureau
- Laboratory of Experimental Medicine (ULB222), CHU Charleroi, Université Libre de Bruxelles, Montigny le Tilleul, Belgium
| | - Dorle Hennig
- Department of Molecular Medicine, Cancer and Inflammation Research, University of Southern Denmark, 5000 Odense C, Denmark
| | - Jonas H Graversen
- Department of Molecular Medicine, Cancer and Inflammation Research, University of Southern Denmark, 5000 Odense C, Denmark
| | - Fabrice Homblé
- Laboratory of Structure and Function of Biological Membranes, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Pepe Ekulu Mfutu
- Pediatric Nephrology, University Hospital Leuven, 3000 Leuven, Belgium
| | | | - Ana Raquel Ramos
- Institute of Interdisciplinary Research in Human and Molecular Biology, Campus Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Rita M La Rovere
- Laboratory of Molecular and Cellular Signalling, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Tomas Luyten
- Laboratory of Molecular and Cellular Signalling, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Marjorie Vermeersch
- Center for Microscopy and Molecular Imaging (CMMI), Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Patricia Tebabi
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Marc Dieu
- URBC-Narilis, University of Namur, 5000 Namur, Belgium
| | - Bart Cuypers
- Biomedical Sciences Department, Institute of Tropical Medicine, 2000 Antwerpen, Belgium; Adrem Data Lab, Department of Mathematics and Computer Science, University of Antwerp, 2000 Antwerpen, Belgium
| | - Stijn Deborggraeve
- Biomedical Sciences Department, Institute of Tropical Medicine, 2000 Antwerpen, Belgium
| | - Marion Rabant
- Adult Nephrology-Transplantation Department, Paris Hospitals and Paris Descartes University, 75006 Paris, France
| | - Christophe Legendre
- Pathology Department, Paris Hospitals and Paris Descartes University, 75006 Paris, France
| | - Søren K Moestrup
- Department of Molecular Medicine, Cancer and Inflammation Research, University of Southern Denmark, 5000 Odense C, Denmark; Department of Biomedicine, University of Aarhus, 8000 Aarhus, Denmark
| | - Elena Levtchenko
- Pediatric Nephrology, University Hospital Leuven, 3000 Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Christophe Erneux
- Institute of Interdisciplinary Research in Human and Molecular Biology, Campus Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - David Pérez-Morga
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium; Center for Microscopy and Molecular Imaging (CMMI), Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Etienne Pays
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium.
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21
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Fuchs P, Rugen N, Carrie C, Elsässer M, Finkemeier I, Giese J, Hildebrandt TM, Kühn K, Maurino VG, Ruberti C, Schallenberg-Rüdinger M, Steinbeck J, Braun HP, Eubel H, Meyer EH, Müller-Schüssele SJ, Schwarzländer M. Single organelle function and organization as estimated from Arabidopsis mitochondrial proteomics. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:420-441. [PMID: 31520498 DOI: 10.1111/tpj.14534] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/23/2019] [Accepted: 08/28/2019] [Indexed: 05/14/2023]
Abstract
Mitochondria host vital cellular functions, including oxidative phosphorylation and co-factor biosynthesis, which are reflected in their proteome. At the cellular level plant mitochondria are organized into hundreds of discrete functional entities, which undergo dynamic fission and fusion. It is the individual organelle that operates in the living cell, yet biochemical and physiological assessments have exclusively focused on the characteristics of large populations of mitochondria. Here, we explore the protein composition of an individual average plant mitochondrion to deduce principles of functional and structural organisation. We perform proteomics on purified mitochondria from cultured heterotrophic Arabidopsis cells with intensity-based absolute quantification and scale the dataset to the single organelle based on criteria that are justified by experimental evidence and theoretical considerations. We estimate that a total of 1.4 million protein molecules make up a single Arabidopsis mitochondrion on average. Copy numbers of the individual proteins span five orders of magnitude, ranging from >40 000 for Voltage-Dependent Anion Channel 1 to sub-stoichiometric copy numbers, i.e. less than a single copy per single mitochondrion, for several pentatricopeptide repeat proteins that modify mitochondrial transcripts. For our analysis, we consider the physical and chemical constraints of the single organelle and discuss prominent features of mitochondrial architecture, protein biogenesis, oxidative phosphorylation, metabolism, antioxidant defence, genome maintenance, gene expression, and dynamics. While assessing the limitations of our considerations, we exemplify how our understanding of biochemical function and structural organization of plant mitochondria can be connected in order to obtain global and specific insights into how organelles work.
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Affiliation(s)
- Philippe Fuchs
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
- Institut für Nutzpflanzenforschung und Ressourcenschutz (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, 53113, Bonn, Germany
| | - Nils Rugen
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Chris Carrie
- Department Biologie I - Botanik, Ludwig-Maximilians-Universität München, Grosshadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Marlene Elsässer
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
- Institut für Nutzpflanzenforschung und Ressourcenschutz (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, 53113, Bonn, Germany
- Institut für Zelluläre und Molekulare Botanik (IZMB), Rheinische Friedrich-Wilhelms-Universität Bonn, Kirschallee 1, 53115, Bonn, Germany
| | - Iris Finkemeier
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
| | - Jonas Giese
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
| | - Tatjana M Hildebrandt
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Kristina Kühn
- Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 10, 06120, Halle/Saale, Germany
| | - Veronica G Maurino
- Institute of Developmental and Molecular Biology of Plants, and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Cristina Ruberti
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
| | - Mareike Schallenberg-Rüdinger
- Institut für Zelluläre und Molekulare Botanik (IZMB), Rheinische Friedrich-Wilhelms-Universität Bonn, Kirschallee 1, 53115, Bonn, Germany
| | - Janina Steinbeck
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
| | - Hans-Peter Braun
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Holger Eubel
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Etienne H Meyer
- Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 10, 06120, Halle/Saale, Germany
| | - Stefanie J Müller-Schüssele
- Institut für Nutzpflanzenforschung und Ressourcenschutz (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, 53113, Bonn, Germany
| | - Markus Schwarzländer
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität, Schlossplatz 7-8, 48143, Münster, Germany
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22
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Corradi V, Sejdiu BI, Mesa-Galloso H, Abdizadeh H, Noskov SY, Marrink SJ, Tieleman DP. Emerging Diversity in Lipid-Protein Interactions. Chem Rev 2019; 119:5775-5848. [PMID: 30758191 PMCID: PMC6509647 DOI: 10.1021/acs.chemrev.8b00451] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Indexed: 02/07/2023]
Abstract
Membrane lipids interact with proteins in a variety of ways, ranging from providing a stable membrane environment for proteins to being embedded in to detailed roles in complicated and well-regulated protein functions. Experimental and computational advances are converging in a rapidly expanding research area of lipid-protein interactions. Experimentally, the database of high-resolution membrane protein structures is growing, as are capabilities to identify the complex lipid composition of different membranes, to probe the challenging time and length scales of lipid-protein interactions, and to link lipid-protein interactions to protein function in a variety of proteins. Computationally, more accurate membrane models and more powerful computers now enable a detailed look at lipid-protein interactions and increasing overlap with experimental observations for validation and joint interpretation of simulation and experiment. Here we review papers that use computational approaches to study detailed lipid-protein interactions, together with brief experimental and physiological contexts, aiming at comprehensive coverage of simulation papers in the last five years. Overall, a complex picture of lipid-protein interactions emerges, through a range of mechanisms including modulation of the physical properties of the lipid environment, detailed chemical interactions between lipids and proteins, and key functional roles of very specific lipids binding to well-defined binding sites on proteins. Computationally, despite important limitations, molecular dynamics simulations with current computer power and theoretical models are now in an excellent position to answer detailed questions about lipid-protein interactions.
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Affiliation(s)
- Valentina Corradi
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Besian I. Sejdiu
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Haydee Mesa-Galloso
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Haleh Abdizadeh
- Groningen
Biomolecular Sciences and Biotechnology Institute and Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Sergei Yu. Noskov
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute and Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - D. Peter Tieleman
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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23
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Queralt-Martín M, Bergdoll L, Jacobs D, Bezrukov SM, Abramson J, Rostovtseva TK. Assessing the role of residue E73 and lipid headgroup charge in VDAC1 voltage gating. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2019; 1860:22-29. [PMID: 30412693 PMCID: PMC8283775 DOI: 10.1016/j.bbabio.2018.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/05/2018] [Accepted: 11/04/2018] [Indexed: 12/25/2022]
Abstract
The voltage-dependent anion channel (VDAC) is the most abundant protein of the mitochondrial outer membrane (MOM) where it regulates transport of ions and metabolites in and out of the organelle. VDAC function is extensively studied in a lipid bilayer system that allows conductance monitoring of reconstituted channels under applied voltage. The process of switching from a high-conductance state, open to metabolites, to a variety of low-conducting states, which excludes metabolite transport, is termed voltage gating and the mechanism remains poorly understood. Recent studies have implicated the involvement of the membrane-solvated residue E73 in the gating process through β-barrel destabilization. However, there has been no direct experimental evidence of E73 involvement in VDAC1 voltage gating. Here, using electrophysiology measurements, we exclude the involvement of E73 in murine VDAC1 (mVDAC1) voltage gating process. With an established protocol of assessing voltage gating of VDACs reconstituted into planar lipid membranes, we definitively show that mVDAC1 gating properties do not change when E73 is replaced by either a glutamine or an alanine. We further demonstrate that cholesterol has no effect on mVDAC1 gating characteristics, though it was shown that E73 is coordinating residue in the cholesterol binding site. In contrast, we found a pronounced gating effect based on the charge of the phospholipid headgroup, where the positive charge stimulates and negative charge suppresses gating. These findings call for critical evaluation of the existing models of VDAC gating and contribute to our understanding of VDAC's role in control of MOM permeability and regulation of mitochondrial respiration and metabolism.
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Affiliation(s)
- María Queralt-Martín
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Lucie Bergdoll
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | - Daniel Jacobs
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sergey M. Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | - Tatiana K. Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA,To whom correspondence should be addressed: Tatiana K. Rostovtseva, Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 9, Room 1E-106, Bethesda, MD 20892-0924. Phone: (301) 402-4702, ; Jeff Abramson, Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095. Phone: (310) 825-3913,
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24
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Van Liefferinge F, Krammer EM, Sengupta D, Prévost M. Lipid composition and salt concentration as regulatory factors of the anion selectivity of VDAC studied by coarse-grained molecular dynamics simulations. Chem Phys Lipids 2018; 220:66-76. [PMID: 30448398 DOI: 10.1016/j.chemphyslip.2018.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/08/2018] [Accepted: 11/12/2018] [Indexed: 12/27/2022]
Abstract
The voltage-dependent anion channel (VDAC) is a mitochondrial outer membrane protein whose fundamental function is to facilitate and regulate the flow of metabolites between the cytosol and the mitochondrial intermembrane space. Using coarse-grained molecular dynamics simulations, we investigated the dependence of VDAC selectivity towards small inorganic anions on two factors: the ionic strength and the lipid composition. In agreement with experimental data we found that VDAC becomes less anion selective with increasing salt concentration due to the screening of a few basic residues that point into the pore lumen. The molecular dynamics simulations provide insight into the regulation mechanism of VDAC selectivity by the composition in the lipid membrane and suggest that the ion distribution is differently modulated by POPE compared to the POPC bilayer. This occurs through the more persistent interactions of acidic residues located at both rims of the β-barrel with head groups of POPE which in turn impact the electrostatic potential and thereby the selectivity of the pore. This mechanism occurs not only in POPE single component membranes but also in a mixed POPE/POPC bilayer by an enrichment of POPE over POPC lipids on the surface of VDAC. Thus we show here that computationally-inexpensive coarse-grained simulations are able to capture, in a semi-quantitative way, essential features of VDAC anion selectivity and could pave the way toward a molecular level understanding of metabolite transport in natural membranes.
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Affiliation(s)
- F Van Liefferinge
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - E-M Krammer
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - D Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - M Prévost
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Brussels, Belgium.
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25
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Kojima S, Iwamoto M, Oiki S, Tochigi S, Takahashi H. Thylakoid membranes contain a non-selective channel permeable to small organic molecules. J Biol Chem 2018; 293:7777-7785. [PMID: 29602906 DOI: 10.1074/jbc.ra118.002367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/20/2018] [Indexed: 11/06/2022] Open
Abstract
The thylakoid lumen is a membrane-enclosed aqueous compartment. Growing evidence indicates that the thylakoid lumen is not only a sink for protons and inorganic ions translocated during photosynthetic reactions but also a place for metabolic activities, e.g. proteolysis of photodamaged proteins, to sustain efficient photosynthesis. However, the mechanism whereby organic molecules move across the thylakoid membranes to sustain these lumenal activities is not well understood. In a recent study of Cyanophora paradoxa chloroplasts (muroplasts), we fortuitously detected a conspicuous diffusion channel activity in the thylakoid membranes. Here, using proteoliposomes reconstituted with the thylakoid membranes from muroplasts and from two other phylogenetically distinct organisms, cyanobacterium Synechocystis sp. PCC 6803 and spinach, we demonstrated the existence of nonselective channels large enough for enabling permeation of small organic compounds (e.g. carbohydrates and amino acids with Mr < 1500) in the thylakoid membranes. Moreover, we purified, identified, and characterized a muroplast channel named here CpTPOR. Osmotic swelling experiments revealed that CpTPOR forms a nonselective pore with an estimated radius of ∼1.3 nm. A lipid bilayer experiment showed variable-conductance channel activity with a typical single-channel conductance of 1.8 nS in 1 m KCl with infrequent closing transitions. The CpTPOR amino acid sequence was moderately similar to that of a voltage-dependent anion-selective channel of the mitochondrial outer membrane, although CpTPOR exhibited no obvious selectivity for anions and no voltage-dependent gating. We propose that transmembrane diffusion pathways are ubiquitous in the thylakoid membranes, presumably enabling rapid transfer of various metabolites between the lumen and stroma.
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Affiliation(s)
- Seiji Kojima
- From the Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8577, Japan, .,the Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan, and
| | - Masayuki Iwamoto
- the Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Shigetoshi Oiki
- the Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Saeko Tochigi
- From the Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8577, Japan.,the Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan, and
| | - Hideyuki Takahashi
- the Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan, and
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26
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Muallem S, Chung WY, Jha A, Ahuja M. Lipids at membrane contact sites: cell signaling and ion transport. EMBO Rep 2017; 18:1893-1904. [PMID: 29030479 DOI: 10.15252/embr.201744331] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/10/2017] [Accepted: 09/21/2017] [Indexed: 12/14/2022] Open
Abstract
Communication between organelles is essential to coordinate cellular functions and the cell's response to physiological and pathological stimuli. Organellar communication occurs at membrane contact sites (MCSs), where the endoplasmic reticulum (ER) membrane is tethered to cellular organelle membranes by specific tether proteins and where lipid transfer proteins and cell signaling proteins are located. MCSs have many cellular functions and are the sites of lipid and ion transfer between organelles and generation of second messengers. This review discusses several aspects of MCSs in the context of lipid transfer, formation of lipid domains, generation of Ca2+ and cAMP second messengers, and regulation of ion transporters by lipids.
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Affiliation(s)
- Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | - Woo Young Chung
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | - Archana Jha
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
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27
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Mlayeh L, Krammer EM, Léonetti M, Prévost M, Homblé F. The mitochondrial VDAC of bean seeds recruits phosphatidylethanolamine lipids for its proper functioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:786-794. [PMID: 28666835 DOI: 10.1016/j.bbabio.2017.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/28/2017] [Accepted: 06/24/2017] [Indexed: 12/31/2022]
Abstract
The voltage-dependent anion-selective channel (VDAC) is the main pathway for inorganic ions and metabolites through the mitochondrial outer membrane. Studies recently demonstrated that membrane lipids regulate its function. It remains, however, unclear how this regulation takes place. In this study, we show that phospholipids are key regulators of Phaseolus VDAC function and, furthermore, that the salt concentration modulates this regulation. Both selectivity and voltage dependence of Phaseolus VDAC are very sensitive to a change in the lipid polar head from PC to PE. Interestingly enough, this dependence is observed only at low salt concentration. Furthermore, significant changes in VDAC functional properties also occur with the gradual methylation of the PE group pointing to the role of subtle chemical variations in the lipid head group. The dependence of PcVDAC gating upon the introduction of a small mole fraction of PE in a PC bilayer has prompted us to propose the existence of a specific interaction site for PE on the outer surface of PcVDAC. Eventually, comparative modeling and molecular dynamics simulations suggest a potential mechanism to get insight into the anion selectivity enhancement of PcVDAC observed in PE relative to PC.
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Affiliation(s)
- Lamia Mlayeh
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Brussels, Belgium
| | - Eva-Maria Krammer
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Brussels, Belgium.
| | - Marc Léonetti
- I.R.P.H.E., Aix-Marseille Université, CNRS, Technopôle de Château-Gombert, F-13384, Marseille Cedex 13, France.
| | - Martine Prévost
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Brussels, Belgium.
| | - Fabrice Homblé
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Brussels, Belgium.
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28
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Budelier MM, Cheng WWL, Bergdoll L, Chen ZW, Janetka JW, Abramson J, Krishnan K, Mydock-McGrane L, Covey DF, Whitelegge JP, Evers AS. Photoaffinity labeling with cholesterol analogues precisely maps a cholesterol-binding site in voltage-dependent anion channel-1. J Biol Chem 2017; 292:9294-9304. [PMID: 28396346 DOI: 10.1074/jbc.m116.773069] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/31/2017] [Indexed: 12/31/2022] Open
Abstract
Voltage-dependent anion channel-1 (VDAC1) is a highly regulated β-barrel membrane protein that mediates transport of ions and metabolites between the mitochondria and cytosol of the cell. VDAC1 co-purifies with cholesterol and is functionally regulated by cholesterol, among other endogenous lipids. Molecular modeling studies based on NMR observations have suggested five cholesterol-binding sites in VDAC1, but direct experimental evidence for these sites is lacking. Here, to determine the sites of cholesterol binding, we photolabeled purified mouse VDAC1 (mVDAC1) with photoactivatable cholesterol analogues and analyzed the photolabeled sites with both top-down mass spectrometry (MS), and bottom-up MS paired with a clickable, stable isotope-labeled tag, FLI-tag. Using cholesterol analogues with a diazirine in either the 7 position of the steroid ring (LKM38) or the aliphatic tail (KK174), we mapped a binding pocket in mVDAC1 localized to Thr83 and Glu73, respectively. When Glu73 was mutated to a glutamine, KK174 no longer photolabeled this residue, but instead labeled the nearby Tyr62 within this same binding pocket. The combination of analytical strategies employed in this work permits detailed molecular mapping of a cholesterol-binding site in a protein, including an orientation of the sterol within the site. Our work raises the interesting possibility that cholesterol-mediated regulation of VDAC1 may be facilitated through a specific binding site at the functionally important Glu73 residue.
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Affiliation(s)
- Melissa M Budelier
- From the Departments of Anesthesiology.,Biochemistry and Molecular Biophysics
| | | | | | - Zi-Wei Chen
- From the Departments of Anesthesiology.,the Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, Missouri 63110
| | | | - Jeff Abramson
- the Departments of Physiology and.,the Institute for Stem Cell Biology and Regenerative Medicine, Nation Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065 Karnataka, India
| | | | | | - Douglas F Covey
- From the Departments of Anesthesiology.,the Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, Missouri 63110.,Developmental Biology, and.,Psychiatry, and
| | - Julian P Whitelegge
- Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, and
| | - Alex S Evers
- From the Departments of Anesthesiology, .,the Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, Missouri 63110.,Developmental Biology, and
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29
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Maurya SR, Mahalakshmi R. Mitochondrial VDAC2 and cell homeostasis: highlighting hidden structural features and unique functionalities. Biol Rev Camb Philos Soc 2016; 92:1843-1858. [PMID: 28980434 DOI: 10.1111/brv.12311] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023]
Abstract
Voltage-dependent anion channels (VDACs) are the gateway to mitochondrial processes, interlinking the cytosolic and mitochondrial compartments. The mitochondrion acts as a storehouse for cytochrome c, the effector of apoptosis, and hence VDACs become intricately involved in the apoptotic pathway. Isoform 1 of VDAC is abundant in the outer mitochondrial membrane of many cell types, while isoform 2 is the preferred channel in specialized cells including brain and some cancer cells. The primary role of VDACs is metabolite flux. The pro- and anti-apoptotic role of VDAC1 and VDAC2, respectively, are secondary, and are influenced by external factors and interacting proteins. Herein, we focus on the less-studied VDAC2, and shed light on its unique functions and features. VDAC2, along with sharing many of its functions with VDAC1, such as metabolite and Ca2+ transport, also has many delineating functions. VDAC2 is closely engaged in the gametogenesis and steroidogenesis pathways and in protection from oxidative stress as well as in neurodegenerative diseases like Alzheimer's and epilepsy. A closer examination of the functional pathways of VDACs indicates that the unique functions of VDAC2 are a result of the different interactome of this isoform. We couple functional differences to the structural and biophysical evidence obtained for the VDACs, and present a testament of why the two VDAC isoforms with >90% sequence similarity, are functionally diverse. Based on these differences, we suggest that the VDAC isoforms now be considered as paralogs. An in-depth understanding of VDAC2 will help us to design better biomolecule targets for cancer and neurodegenerative diseases.
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Affiliation(s)
- Svetlana Rajkumar Maurya
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462066, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, 462066, India
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30
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Tsai KJ, Lin CY, Ting CY, Shih MC. Ethylene-Regulated Glutamate Dehydrogenase Fine-Tunes Metabolism during Anoxia-Reoxygenation. PLANT PHYSIOLOGY 2016; 172:1548-1562. [PMID: 27677986 PMCID: PMC5100772 DOI: 10.1104/pp.16.00985] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/24/2016] [Indexed: 05/19/2023]
Abstract
Ethylene is an essential hormone in plants that is involved in low-oxygen and reoxygenation responses. As a key transcription factor in ethylene signaling, ETHYLENE INSENSITIVE3 (EIN3) activates targets that trigger various responses. However, most of these targets are still poorly characterized. Through analyses of our microarray data and the published Arabidopsis (Arabidopsis thaliana) EIN3 chromatin immunoprecipitation sequencing data set, we inferred the putative targets of EIN3 during anoxia-reoxygenation. Among them, GDH2, which encodes one subunit of glutamate dehydrogenase (GDH), was chosen for further studies for its role in tricarboxylic acid cycle replenishment. We demonstrated that both GDH1 and GDH2 are induced during anoxia and reoxygenation and that this induction is mediated via ethylene signaling. In addition, the results of enzymatic assays showed that the level of GDH during anoxia-reoxygenation decreased in the ethylene-insensitive mutants ein2-5 and ein3eil1 Global metabolite analysis indicated that the deamination activity of GDH might regenerate 2-oxoglutarate, which is a cosubstrate that facilitates the breakdown of alanine by alanine aminotransferase when reoxygenation occurs. Moreover, ineffective tricarboxylic acid cycle replenishment, disturbed carbohydrate metabolism, reduced phytosterol biosynthesis, and delayed energy regeneration were found in gdh1gdh2 and ethylene mutants during reoxygenation. Taken together, these data illustrate the essential role of EIN3-regulated GDH activity in metabolic adjustment during anoxia-reoxygenation.
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Affiliation(s)
- Kuen-Jin Tsai
- Institute of Plant Biology, National Taiwan University, Taipei 115, Taiwan (K.-J.T., M.-C.S.); and
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (K.-J.T., C.-Y.L., C.-Y.T., M.-C.S.)
| | - Chih-Yu Lin
- Institute of Plant Biology, National Taiwan University, Taipei 115, Taiwan (K.-J.T., M.-C.S.); and
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (K.-J.T., C.-Y.L., C.-Y.T., M.-C.S.)
| | - Chen-Yun Ting
- Institute of Plant Biology, National Taiwan University, Taipei 115, Taiwan (K.-J.T., M.-C.S.); and
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (K.-J.T., C.-Y.L., C.-Y.T., M.-C.S.)
| | - Ming-Che Shih
- Institute of Plant Biology, National Taiwan University, Taipei 115, Taiwan (K.-J.T., M.-C.S.); and
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (K.-J.T., C.-Y.L., C.-Y.T., M.-C.S.)
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31
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Carraretto L, Checchetto V, De Bortoli S, Formentin E, Costa A, Szabó I, Teardo E. Calcium Flux across Plant Mitochondrial Membranes: Possible Molecular Players. FRONTIERS IN PLANT SCIENCE 2016; 7:354. [PMID: 27065186 PMCID: PMC4814809 DOI: 10.3389/fpls.2016.00354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 03/07/2016] [Indexed: 05/24/2023]
Abstract
Plants, being sessile organisms, have evolved the ability to integrate external stimuli into metabolic and developmental signals. A wide variety of signals, including abiotic, biotic, and developmental stimuli, were observed to evoke specific spatio-temporal Ca(2+) transients which are further transduced by Ca(2+) sensor proteins into a transcriptional and metabolic response. Most of the research on Ca(2+) signaling in plants has been focused on the transport mechanisms for Ca(2+) across the plasma- and the vacuolar membranes as well as on the components involved in decoding of cytoplasmic Ca(2+) signals, but how intracellular organelles such as mitochondria are involved in the process of Ca(2+) signaling is just emerging. The combination of the molecular players and the elicitors of Ca(2+) signaling in mitochondria together with newly generated detection systems for measuring organellar Ca(2+) concentrations in plants has started to provide fruitful grounds for further discoveries. In the present review we give an updated overview of the currently identified/hypothesized pathways, such as voltage-dependent anion channels, homologs of the mammalian mitochondrial uniporter (MCU), LETM1, a plant glutamate receptor family member, adenine nucleotide/phosphate carriers and the permeability transition pore (PTP), that may contribute to the transport of Ca(2+) across the outer and inner mitochondrial membranes in plants. We briefly discuss the relevance of the mitochondrial Ca(2+) homeostasis for ensuring optimal bioenergetic performance of this organelle.
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Affiliation(s)
| | - Vanessa Checchetto
- Department of Biology, University of PadovaPadova, Italy
- Department of Biomedical Sciences, University of PadovaPadova, Italy
| | | | - Elide Formentin
- Department of Biology, University of PadovaPadova, Italy
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
| | - Alex Costa
- Department of Biosciences, University of MilanMilan, Italy
- CNR, Institute of Biophysics, Consiglio Nazionale delle RicercheMilan, Italy
| | - Ildikó Szabó
- Department of Biology, University of PadovaPadova, Italy
- CNR, Institute of NeurosciencesPadova, Italy
| | - Enrico Teardo
- Department of Biology, University of PadovaPadova, Italy
- CNR, Institute of NeurosciencesPadova, Italy
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32
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The N-terminus of VDAC: Structure, mutational analysis, and a potential role in regulating barrel shape. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1350-61. [PMID: 26997586 DOI: 10.1016/j.bbamem.2016.03.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/12/2016] [Accepted: 03/17/2016] [Indexed: 01/24/2023]
Abstract
A novel feature of the voltage-dependent anion channel (VDAC, mitochondrial porin), is the barrel, comprising an odd number of β-strands and closed by parallel strands. Recent research has focused on the N-terminal segment, which in the available structures, resides in the lumen and is not part of the barrel. In this review, the structural data obtained from vertebrate VDAC are integrated with those from VDAC in artificial bilayers, emphasizing the array of native and tagged versions of VDAC used. The data are discussed with respect to a recent gating model (Zachariae et al. (2012) Structure 20:1-10), in which the N-terminus acts not as a gate on a stable barrel, but rather stabilizes the barrel, preventing its shift into a partially collapsed, low-conductance, closed state. Additionally, the role of the N-terminus in VDAC oligomerization, apoptosis through interactions with hexokinase and its interaction with ATP are discussed briefly.
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33
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Karachitos A, Grobys D, Antoniewicz M, Jedut S, Jordan J, Kmita H. Human VDAC isoforms differ in their capability to interact with minocycline and to contribute to its cytoprotective activity. Mitochondrion 2016; 28:38-48. [PMID: 26994639 DOI: 10.1016/j.mito.2016.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/21/2016] [Accepted: 03/14/2016] [Indexed: 11/19/2022]
Abstract
It has been previously demonstrated that cytoprotective activity displayed by minocycline in the case of the yeast Saccharomyces cerevisiae cells pretreated with H2O2 requires the presence of functional VDAC (YVDAC1). Thus, we decided to transform YVDAC1-depleted yeast cells (Δpor1 cells) with plasmids expressing human VDAC isoforms (HVDAC1, HVDAC2, HVDAC3) to estimate their involvement in the minocycline cytoprotective effect. We observed that only expression of HVDAC3 in Δpor1 cells provided minocycline-mediated cytoprotection against H2O2 although all human isoforms are functional in Δpor1 cells. The observation appears to be important for on-going discussion concerning VDAC isoform roles in mitochondria and cell functioning.
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Affiliation(s)
- Andonis Karachitos
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Daria Grobys
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Monika Antoniewicz
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Sylwia Jedut
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Joaquin Jordan
- Department of Medical Sciences, University of Castilla-La Mancha, School of Medicine, Albacete, Spain
| | - Hanna Kmita
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
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34
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Lange Y, Steck TL. Active membrane cholesterol as a physiological effector. Chem Phys Lipids 2016; 199:74-93. [PMID: 26874289 DOI: 10.1016/j.chemphyslip.2016.02.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/04/2016] [Accepted: 02/08/2016] [Indexed: 02/05/2023]
Abstract
Sterols associate preferentially with plasma membrane sphingolipids and saturated phospholipids to form stoichiometric complexes. Cholesterol in molar excess of the capacity of these polar bilayer lipids has a high accessibility and fugacity; we call this fraction active cholesterol. This review first considers how active cholesterol serves as an upstream regulator of cellular sterol homeostasis. The mechanism appears to utilize the redistribution of active cholesterol down its diffusional gradient to the endoplasmic reticulum and mitochondria, where it binds multiple effectors and directs their feedback activity. We have also reviewed a broad literature in search of a role for active cholesterol (as opposed to bulk cholesterol or lipid domains such as rafts) in the activity of diverse membrane proteins. Several systems provide such evidence, implicating, in particular, caveolin-1, various kinds of ABC-type cholesterol transporters, solute transporters, receptors and ion channels. We suggest that this larger role for active cholesterol warrants close attention and can be tested easily.
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Affiliation(s)
- Yvonne Lange
- Department of Pathology, Rush University Medical Center, 1653 W. Congress Parkway, Chicago, IL 60612, USA.
| | - Theodore L Steck
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
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35
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Saidani H, Grobys D, Léonetti M, Kmita H, Homblé F. Towards understanding of plant mitochondrial VDAC proteins: an overview of bean ( Phaseolus) VDAC proteins. AIMS BIOPHYSICS 2016. [DOI: 10.3934/biophy.2017.1.43] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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36
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Krammer EM, Vu GT, Homblé F, Prévost M. Dual mechanism of ion permeation through VDAC revealed with inorganic phosphate ions and phosphate metabolites. PLoS One 2015; 10:e0121746. [PMID: 25860993 PMCID: PMC4393092 DOI: 10.1371/journal.pone.0121746] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/03/2015] [Indexed: 11/19/2022] Open
Abstract
In the exchange of metabolites and ions between the mitochondrion and the cytosol, the voltage-dependent anion channel (VDAC) is a key element, as it forms the major transport pathway for these compounds through the mitochondrial outer membrane. Numerous experimental studies have promoted the idea that VDAC acts as a regulator of essential mitochondrial functions. In this study, using a combination of molecular dynamics simulations, free-energy calculations, and electrophysiological measurements, we investigated the transport of ions through VDAC, with a focus on phosphate ions and metabolites. We showed that selectivity of VDAC towards small anions including monovalent phosphates arises from short-lived interactions with positively charged residues scattered throughout the pore. In dramatic contrast, permeation of divalent phosphate ions and phosphate metabolites (AMP and ATP) involves binding sites along a specific translocation pathway. This permeation mechanism offers an explanation for the decrease in VDAC conductance measured in the presence of ATP or AMP at physiological salt concentration. The binding sites occur at similar locations for the divalent phosphate ions, AMP and ATP, and contain identical basic residues. ATP features a marked affinity for a central region of the pore lined by two lysines and one arginine of the N-terminal helix. This cluster of residues together with a few other basic amino acids forms a "charged brush" which facilitates the passage of the anionic metabolites through the pore. All of this reveals that VDAC controls the transport of the inorganic phosphates and phosphate metabolites studied here through two different mechanisms.
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Affiliation(s)
- Eva-Maria Krammer
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Giang Thi Vu
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Fabrice Homblé
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Martine Prévost
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Brussels, Belgium
- * E-mail: (MP)
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37
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Mitochondrial cholesterol: mechanisms of import and effects on mitochondrial function. J Bioenerg Biomembr 2014; 48:137-51. [PMID: 25425472 DOI: 10.1007/s10863-014-9592-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/14/2014] [Indexed: 12/23/2022]
Abstract
Mitochondria require cholesterol for biogenesis and membrane maintenance, and for the synthesis of steroids, oxysterols and hepatic bile acids. Multiple pathways mediate the transport of cholesterol from different subcellular pools to mitochondria. In steroidogenic cells, the steroidogenic acute regulatory protein (StAR) interacts with a mitochondrial protein complex to mediate cholesterol delivery to the inner mitochondrial membrane for conversion to pregnenolone. In non-steroidogenic cells, several members of a protein family defined by the presence of a StAR-related lipid transfer (START) domain play key roles in the delivery of cholesterol to mitochondrial membranes. Subdomains of the endoplasmic reticulum (ER), termed mitochondria-associated ER membranes (MAM), form membrane contact sites with mitochondria and may contribute to the transport of ER cholesterol to mitochondria, either independently or in conjunction with lipid-transfer proteins. Model systems of mitochondria enriched with cholesterol in vitro and mitochondria isolated from cells with (patho)physiological mitochondrial cholesterol accumulation clearly demonstrate that mitochondrial cholesterol levels affect mitochondrial function. Increased mitochondrial cholesterol levels have been observed in several diseases, including cancer, ischemia, steatohepatitis and neurodegenerative diseases, and influence disease pathology. Hence, a deeper understanding of the mechanisms maintaining mitochondrial cholesterol homeostasis may reveal additional targets for therapeutic intervention. Here we give a brief overview of mitochondrial cholesterol import in steroidogenic cells, and then focus on cholesterol trafficking pathways that deliver cholesterol to mitochondrial membranes in non-steroidogenic cells. We also briefly discuss the consequences of increased mitochondrial cholesterol levels on mitochondrial function and their potential role in disease pathology.
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38
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Goulart CL, Bisch PM, von Krüger WMA, Homblé F. VCA1008: An Anion-Selective Porin of Vibrio Cholerae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:680-7. [PMID: 25462170 DOI: 10.1016/j.bbamem.2014.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 11/05/2014] [Accepted: 11/10/2014] [Indexed: 01/14/2023]
Abstract
A putative porin function has been assigned to VCA1008 of Vibrio cholerae. Its coding gene, vca1008, is expressed upon colonization of the small intestine in infant mice and human volunteers, and is essential for infection. In vitro, vca1008 is expressed under inorganic phosphate limitation and, in this condition, VCA1008 is the major outer membrane protein of the bacterium. Here, we provide the first functional characterization of VCA1008 reconstituted into planar lipid bilayers. Our main findings were: 1) VCA1008 forms an ion channel that, at high voltage (~±100 mV), presents a voltage-dependent activity and displays closures typical of trimeric porins, with a conductance of 4.28±0.04 nS (n=164) in 1M KCl; 2) It has a preferred selectivity for anions over cations; 3) Its conductance saturates with increasing inorganic phosphate concentration, suggesting VCA1008 contains binding site(s) for this anion; 4) Its ion selectivity is controlled by both fixed charged residues within the channel and diffusion along the pore; 5) Partitioning of poly (ethylene glycol)s (PEGs) of different molecular mass suggests that VCA1008 channel has a pore exclusion limit of 0.9 nm.
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Affiliation(s)
- Carolina L Goulart
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Faculté des Sciences, Université Libre de Bruxelles, Campus Plaine (CP 206/2), B - 1050 Brussels, Belgium
| | - Paulo M Bisch
- Laboratório de Física Biológica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanda M A von Krüger
- Laboratório de Física Biológica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabrice Homblé
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Faculté des Sciences, Université Libre de Bruxelles, Campus Plaine (CP 206/2), B - 1050 Brussels, Belgium.
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39
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Weiser BP, Bu W, Wong D, Eckenhoff RG. Sites and functional consequence of VDAC-alkylphenol anesthetic interactions. FEBS Lett 2014; 588:4398-403. [PMID: 25448677 DOI: 10.1016/j.febslet.2014.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 09/10/2014] [Accepted: 10/10/2014] [Indexed: 10/24/2022]
Abstract
General anesthetics have previously been shown to bind mitochondrial VDAC. Here, using a photoactive analog of the anesthetic propofol, we determined that alkylphenol anesthetics bind to Gly56 and Val184 on rat VDAC1. By reconstituting rat VDAC into planar bilayers, we determined that propofol potentiates VDAC gating with asymmetry at the voltage polarities; in contrast, propofol does not affect the conductance of open VDAC. Additional experiments showed that propofol also does not affect gramicidin A properties that are sensitive to lipid bilayer mechanics. Together, this suggests propofol affects VDAC function through direct protein binding, likely at the lipid-exposed channel surface, and that gating can be modulated by ligand binding to the distal ends of VDAC β-strands where Gly56 and Val184 are located.
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Affiliation(s)
- Brian P Weiser
- Department of Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States; Department of Pharmacology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Weiming Bu
- Department of Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - David Wong
- Drexel University College of Medicine, Philadelphia, PA 19129, United States
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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40
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Weiser BP, Salari R, Eckenhoff RG, Brannigan G. Computational investigation of cholesterol binding sites on mitochondrial VDAC. J Phys Chem B 2014; 118:9852-60. [PMID: 25080204 PMCID: PMC4141696 DOI: 10.1021/jp504516a] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
The
mitochondrial voltage-dependent anion channel (VDAC) allows
passage of ions and metabolites across the mitochondrial outer membrane.
Cholesterol binds mammalian VDAC, and we investigated the effects
of binding to human VDAC1 with atomistic molecular dynamics simulations
that totaled 1.4 μs. We docked cholesterol to specific sites
on VDAC that were previously identified with NMR, and we tested the
reliability of multiple docking results in each site with simulations.
The most favorable binding modes were used to build a VDAC model with
cholesterol occupying five unique sites, and during multiple 100 ns
simulations, cholesterol stably and reproducibly remained bound to
the protein. For comparison, VDAC was simulated in systems with identical
components but with cholesterol initially unbound. The dynamics of
loops that connect adjacent β-strands were most affected by
bound cholesterol, with the averaged root-mean-square fluctuation
(RMSF) of multiple residues altered by 20–30%. Cholesterol
binding also stabilized charged residues inside the channel and localized
the surrounding electrostatic potentials. Despite this, ion diffusion
through the channel was not significantly affected by bound cholesterol,
as evidenced by multi-ion potential of mean force measurements. Although
we observed modest effects of cholesterol on the open channel, our
model will be particularly useful in experiments that investigate
how cholesterol affects VDAC function under applied electrochemical
forces and also how other ligands and proteins interact with the channel.
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Affiliation(s)
- Brian P Weiser
- Department of Anesthesiology and Critical Care and ‡Department of Pharmacology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104, United States
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41
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Salinas T, El Farouk-Ameqrane S, Ubrig E, Sauter C, Duchêne AM, Maréchal-Drouard L. Molecular basis for the differential interaction of plant mitochondrial VDAC proteins with tRNAs. Nucleic Acids Res 2014; 42:9937-48. [PMID: 25114051 PMCID: PMC4150812 DOI: 10.1093/nar/gku728] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In plants, the voltage-dependent anion-selective channel (VDAC) is a major component of a pathway involved in transfer RNA (tRNA) translocation through the mitochondrial outer membrane. However, the way in which VDAC proteins interact with tRNAs is still unknown. Potato mitochondria contain two major mitochondrial VDAC proteins, VDAC34 and VDAC36. These two proteins, composed of a N-terminal α-helix and of 19 β-strands forming a β-barrel structure, share 75% sequence identity. Here, using both northwestern and gel shift experiments, we report that these two proteins interact differentially with nucleic acids. VDAC34 binds more efficiently with tRNAs or other nucleic acids than VDAC36. To further identify specific features and critical amino acids required for tRNA binding, 21 VDAC34 mutants were constructed and analyzed by northwestern. This allowed us to show that the β-barrel structure of VDAC34 and the first 50 amino acids that contain the α-helix are essential for RNA binding. Altogether the work shows that during evolution, plant mitochondrial VDAC proteins have diverged so as to interact differentially with nucleic acids, and this may reflect their involvement in various specialized biological functions.
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Affiliation(s)
- Thalia Salinas
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France
| | - Samira El Farouk-Ameqrane
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France
| | - Elodie Ubrig
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France
| | - Claude Sauter
- Institut de Biologie Moléculaire et Cellulaire, UPR 9002 CNRS, associated with Strasbourg University, 15 rue René Descartes 67084 Strasbourg cedex, France
| | - Anne-Marie Duchêne
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France
| | - Laurence Maréchal-Drouard
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, associated with Strasbourg University, 12 rue du Général Zimmer 67084 Strasbourg cedex, France
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42
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Poveda J, Giudici A, Renart M, Molina M, Montoya E, Fernández-Carvajal A, Fernández-Ballester G, Encinar J, González-Ros J. Lipid modulation of ion channels through specific binding sites. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1560-7. [DOI: 10.1016/j.bbamem.2013.10.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/24/2013] [Accepted: 10/30/2013] [Indexed: 01/08/2023]
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43
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Kennedy BE, Madreiter CT, Vishnu N, Malli R, Graier WF, Karten B. Adaptations of energy metabolism associated with increased levels of mitochondrial cholesterol in Niemann-Pick type C1-deficient cells. J Biol Chem 2014; 289:16278-89. [PMID: 24790103 DOI: 10.1074/jbc.m114.559914] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Niemann-Pick type C1 (NPC1) is a late endosomal transmembrane protein, which, together with NPC2 in the endosome lumen, mediates the transport of endosomal cholesterol to the plasma membrane and endoplasmic reticulum. Loss of function of NPC1 or NPC2 leads to cholesterol accumulation in late endosomes and causes neuronal dysfunction and neurodegeneration. Recent studies indicate that cholesterol also accumulates in mitochondria of NPC1-deficient cells and brain tissue and that NPC1 deficiency leads to alterations in mitochondrial function and energy metabolism. Here, we have investigated the effects of increased mitochondrial cholesterol levels on energy metabolism, using RNA interference to deplete Chinese hamster ovary cells of NPC1 alone or in combination with MLN64, which mediates endosomal cholesterol transport to mitochondria. Mitochondrial cholesterol levels were also altered by depletion of NPC2 in combination with the expression of NPC2 mutants. We found that the depletion of NPC1 increased lactate secretion, decreased glutamine-dependent mitochondrial respiration, and decreased ATP transport across mitochondrial membranes. These metabolic alterations did not occur when transport of endosomal cholesterol to mitochondria was blocked. In addition, the elevated mitochondrial cholesterol levels in NPC1-depleted cells and in NPC2-depleted cells expressing mutant NPC2 that allows endosomal cholesterol trafficking to mitochondria were associated with increased expression of the antioxidant response factor Nrf2. Antioxidant treatment not only prevented the increase in Nrf2 mRNA levels but also prevented the increased lactate secretion in NPC1-depleted cells. These results suggest that mitochondrial cholesterol accumulation can increase oxidative stress and in turn cause increased glycolysis to lactate and other metabolic alterations.
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Affiliation(s)
- Barry E Kennedy
- From the Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada and
| | - Corina T Madreiter
- the Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Neelanjan Vishnu
- the Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Roland Malli
- the Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Wolfgang F Graier
- the Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Barbara Karten
- From the Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada and
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44
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Krammer EM, Saidani H, Prévost M, Homblé F. Origin of ion selectivity in Phaseolus coccineus mitochondrial VDAC. Mitochondrion 2014; 19 Pt B:206-13. [PMID: 24742372 DOI: 10.1016/j.mito.2014.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 03/14/2014] [Accepted: 04/04/2014] [Indexed: 12/23/2022]
Abstract
The mitochondrial voltage-dependent a nion-selective channel (VDAC) is the major permeation pathway for small ions and metabolites. Although a wealth of electrophysiological data has been obtained on different VDAC species, the physical mechanisms of their ionic selectivity are still elusive. We addressed this issue using electrophysiological experiments performed on plant VDAC. A simple macroscopic electrodiffusion model accounting for ion diffusion and for an effective fixed charge of the channel describes well its selectivity. Brownian Dynamics simulations of ion permeation performed on plant and mammalian VDACs point to the role of specific charged residues located at about the middle of the pore.
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Affiliation(s)
- Eva-Maria Krammer
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Bld du Triomphe, 1050 Brussels, Belgium
| | - Hayet Saidani
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Bld du Triomphe, 1050 Brussels, Belgium
| | - Martine Prévost
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Bld du Triomphe, 1050 Brussels, Belgium
| | - Fabrice Homblé
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Bld du Triomphe, 1050 Brussels, Belgium.
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45
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Ben-Hail D, Shoshan-Barmatz V. Reconstitution of purified VDAC1 into a lipid bilayer and recording of channel conductance. Cold Spring Harb Protoc 2014; 2014:100-105. [PMID: 24371316 DOI: 10.1101/pdb.prot073148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The functional properties of purified voltage-dependent anion-selective channel protein 1 (VDAC1) have been examined in reconstituted systems based on artificially prepared phospholipid bilayers. The most widespread method for the characterization of the pore-forming activity of the mitochondrial VDAC1 protein requires reconstitution of the channel activity into a planar lipid bilayer (PLB) that separates two aqueous compartments. This system is able to produce a refined and large set of information on channel activity. The activity of the channel is reflected in the flow of ions (i.e., current) through a membrane that otherwise represents a barrier to ion flow. The setup thus requires the use of purified protein and a source of continuous current, as well as a sophisticated detector system able to amplify and record low, picoamper-level currents. This system is so efficient that the activity of even a single channel can be detected, allowing for study of VDAC1 at the molecular level.
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Affiliation(s)
- Danya Ben-Hail
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Wriessnegger T, Pichler H. Yeast metabolic engineering – Targeting sterol metabolism and terpenoid formation. Prog Lipid Res 2013; 52:277-93. [DOI: 10.1016/j.plipres.2013.03.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 12/28/2022]
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Krammer EM, Homblé F, Prévost M. Molecular origin of VDAC selectivity towards inorganic ions: a combined molecular and Brownian dynamics study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1284-92. [PMID: 23313453 DOI: 10.1016/j.bbamem.2012.12.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 12/14/2012] [Accepted: 12/31/2012] [Indexed: 11/15/2022]
Abstract
The voltage-dependent anion channel (VDAC) serves as the major pore for metabolites and electrolytes in the outer mitochondrial membrane. To refine our understanding of ion permeation through this channel we performed an extensive Brownian (BD) and molecular dynamics (MD) study on the mouse VDAC isoform 1 wild-type and mutants (K20E, D30K, K61E, E158K and K252E). The selectivity and the conductance of the wild-type and of the variant channels computed from the BD trajectories are in agreement with experimental data. The calculated selectivity is shown to be very sensitive to slight conformational changes which may have some bearing on the variability of the selectivity values measured on the VDAC open state. The MD and BD free energy profiles of the ion permeation suggest that the pore region comprising the N-terminal helix and the barrel band encircling it predominantly controls the ion transport across the channel. The overall 12μs BD and 0.9μs MD trajectories of the mouse VDAC isoform 1 wild-type and mutants feature no distinct pathways for ion diffusion and no long-lived ion-protein interactions. The dependence of ion distribution in the wild-type channel with the salt concentration can be explained by an ionic screening of the permanent charges of the protein arising from the pore. Altogether these results bolster the role of electrostatic features of the pore as the main determinant of VDAC selectivity towards inorganic anions.
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Affiliation(s)
- Eva-Maria Krammer
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles (ULB), Boulevard du Triomphe CP 206/2, B-1050 Brussels, Belgium
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48
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Shoshan-Barmatz V, Mizrachi D. VDAC1: from structure to cancer therapy. Front Oncol 2012; 2:164. [PMID: 23233904 PMCID: PMC3516065 DOI: 10.3389/fonc.2012.00164] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 10/24/2012] [Indexed: 12/14/2022] Open
Abstract
Here, we review current evidence pointing to the function of VDAC1 in cell life and death, and highlight these functions in relation to cancer. Found at the outer mitochondrial membrane, VDAC1 assumes a crucial position in the cell, controlling the metabolic cross-talk between mitochondria and the rest of the cell. Moreover, its location at the boundary between the mitochondria and the cytosol enables VDAC1 to interact with proteins that mediate and regulate the integration of mitochondrial functions with other cellular activities. As a metabolite transporter, VDAC1 contributes to the metabolic phenotype of cancer cells. This is reflected by VDAC1 over-expression in many cancer types, and by inhibition of tumor development upon silencing VDAC1 expression. Along with regulating cellular energy production and metabolism, VDAC1 is also a key protein in mitochondria-mediated apoptosis, participating in the release of apoptotic proteins and interacting with anti-apoptotic proteins. The involvement of VDAC1 in the release of apoptotic proteins located in the inter-membranal space is discussed, as is VDAC1 oligomerization as an important step in apoptosis induction. VDAC also serves as an anchor point for mitochondria-interacting proteins, some of which are also highly expressed in many cancers, such as hexokinase (HK), Bcl2, and Bcl-xL. By binding to VDAC, HK provides both metabolic benefit and apoptosis-suppressive capacity that offers the cell a proliferative advantage and increases its resistance to chemotherapy. VDAC1-based peptides that bind specifically to HK, Bcl2, or Bcl-xL abolished the cell’s abilities to bypass the apoptotic pathway. Moreover, these peptides promote cell death in a panel of genetically characterized cell lines derived from different human cancers. These and other functions point to VDAC1 as a rational target for the development of a new generation of therapeutics.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences, Ben-Gurion University of the Negev Beer-Sheva, Israel ; The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Beer-Sheva, Israel
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Eddy MT, Ong TC, Clark L, Teijido O, van der Wel PCA, Garces R, Wagner G, Rostovtseva TK, Griffin RG. Lipid dynamics and protein-lipid interactions in 2D crystals formed with the β-barrel integral membrane protein VDAC1. J Am Chem Soc 2012; 134:6375-87. [PMID: 22435461 PMCID: PMC3333839 DOI: 10.1021/ja300347v] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We employ a combination of (13)C/(15)N magic angle spinning (MAS) NMR and (2)H NMR to study the structural and functional consequences of different membrane environments on VDAC1 and, conversely, the effect of VDAC1 on the structure of the lipid bilayer. MAS spectra reveal a well-structured VDAC1 in 2D crystals of dimyristoylphosphatidylcholine (DMPC) and diphytanoylphosphatidylcholine (DPhPC), and their temperature dependence suggests that the VDAC structure does not change conformation above and below the lipid phase transition temperature. The same data show that the N-terminus remains structured at both low and high temperatures. Importantly, functional studies based on electrophysiological measurements on these same samples show fully functional channels, even without the presence of Triton X-100 that has been found necessary for in vitro-refolded channels. (2)H solid-state NMR and differential scanning calorimetry were used to investigate the dynamics and phase behavior of the lipids within the VDAC1 2D crystals. (2)H NMR spectra indicate that the presence of protein in DMPC results in a broad lipid phase transition that is shifted from 19 to ~27 °C and show the existence of different lipid populations, consistent with the presence of both annular and bulk lipids in the functionally and structurally homogeneous samples.
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Affiliation(s)
- Matthew T. Eddy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ta-Chung Ong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Lindsay Clark
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Oscar Teijido
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Patrick C. A. van der Wel
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert Garces
- Department of Biological and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Gerhard Wagner
- Department of Biological and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Tatiana K. Rostovtseva
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert G. Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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50
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Homblé F, Krammer EM, Prévost M. Plant VDAC: facts and speculations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1486-501. [PMID: 22155681 DOI: 10.1016/j.bbamem.2011.11.028] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/12/2011] [Accepted: 11/22/2011] [Indexed: 01/01/2023]
Abstract
The voltage-dependent anion-selective channel (VDAC) is the most abundant protein in the mitochondrial outer membrane and the major transport pathway for a large variety of compounds ranging from ions to large polymeric molecules such as DNA and tRNA. Plant VDACs feature a secondary structure content and electrophysiological properties akin to those of VDACs from other organisms. They however undergo a specific regulation. The general importance of VDAC in plant physiology has only recently emerged. Besides their role in metabolite transport, plant VDACs are also involved in the programmed cell death triggered in response to biotic and abiotic stresses. Moreover, their colocalization in non-mitochondrial membranes suggests a diversity of function. This review summarizes our current understanding of the structure and function of plant VDACs. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism.
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Affiliation(s)
- Fabrice Homblé
- Structure et Fontion des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles, Boulevard du Triomphe CP, Brussels, Belgium.
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