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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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2
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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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3
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Mayse LA, Movileanu L. Gating of β-Barrel Protein Pores, Porins, and Channels: An Old Problem with New Facets. Int J Mol Sci 2023; 24:12095. [PMID: 37569469 PMCID: PMC10418385 DOI: 10.3390/ijms241512095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
β barrels are ubiquitous proteins in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria. These transmembrane proteins (TMPs) execute a wide variety of tasks. For example, they can serve as transporters, receptors, membrane-bound enzymes, as well as adhesion, structural, and signaling elements. In addition, multimeric β barrels are common structural scaffolds among many pore-forming toxins. Significant progress has been made in understanding the functional, structural, biochemical, and biophysical features of these robust and versatile proteins. One frequently encountered fundamental trait of all β barrels is their voltage-dependent gating. This process consists of reversible or permanent conformational transitions between a large-conductance, highly permeable open state and a low-conductance, solute-restrictive closed state. Several intrinsic molecular mechanisms and environmental factors modulate this universal property of β barrels. This review article outlines the typical signatures of voltage-dependent gating. Moreover, we discuss recent developments leading to a better qualitative understanding of the closure dynamics of these TMPs.
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Affiliation(s)
- Lauren A. Mayse
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
- The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
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4
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Xia L, Ding S, Wang X, Zhang X, Zhu L, Zhang H, Li H. Advances in ovarian cancer treatment using a combination of statins with other drugs. Front Pharmacol 2023; 13:1048484. [PMID: 36686716 PMCID: PMC9845598 DOI: 10.3389/fphar.2022.1048484] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/14/2022] [Indexed: 01/06/2023] Open
Abstract
New anti-cancer drugs are constantly being developed, especially targeted drugs. Although these drugs have achieved significant clinical efficacy, they do not play a significant role in ovarian cancer. Moreover, the research cycle and costs of such drugs are often huge. The repositioning of conventional drugs has gradually become a concern. Statins, as traditional lipid-lowering drugs, play a role mainly by inhibiting HMGCR. In recent years, epidemiological studies and in vitro experiments have confirmed its anti-cancer effect, especially the effect of anti-ovarian cancer. The mutation rate of TP53 in ovarian cancer is as high as 95%, while HMGCR is often highly expressed in TP53 mutant tumors. However, the effect of prospective clinical trials is not ideal. This result seems understandable considering that it seems unrealistic for a lipid-lowering drug to completely inhibit tumor growth. Therefore, statins play more synergistic roles in the treatment of ovarian cancer. Because ovarian cancer is a highly heterogeneous tumor, it may be a good choice to deeply understand the mechanism of statins in the treatment of ovarian cancer and achieve precise treatment by combining it with other drugs.
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Affiliation(s)
- Lei Xia
- Department of Pathology, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Shichao Ding
- Department of Internal Medicine, The Third Affiliated Hospital of Shandong First Medical University, Jinan, China
| | - Xuezhen Wang
- School of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xiaoyu Zhang
- School of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Lin Zhu
- School of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hairong Zhang
- Department of Obstetrics and Gynecology, Shandong Provincial Third Hospital, Jinan, China,*Correspondence: Hairong Zhang, ; Huirong Li,
| | - Huirong Li
- Department of Obstetrics and Gynecology, Shandong Provincial Third Hospital, Jinan, China,*Correspondence: Hairong Zhang, ; Huirong Li,
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5
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Rister AB, Gudermann T, Schredelseker J. E as in Enigma: The Mysterious Role of the Voltage-Dependent Anion Channel Glutamate E73. Int J Mol Sci 2022; 24:ijms24010269. [PMID: 36613710 PMCID: PMC9820230 DOI: 10.3390/ijms24010269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/07/2022] [Accepted: 12/12/2022] [Indexed: 12/28/2022] Open
Abstract
The voltage-dependent anion channel (VDAC) is the main passageway for ions and metabolites over the outer mitochondrial membrane. It was associated with many physiological processes, including apoptosis and modulation of intracellular Ca2+ signaling. The protein is formed by a barrel of 19 beta-sheets with an N-terminal helix lining the inner pore. Despite its large diameter, the channel can change its selectivity for ions and metabolites based on its open state to regulate transport into and out of mitochondria. VDAC was shown to be regulated by a variety of cellular factors and molecular partners including proteins, lipids and ions. Although the physiological importance of many of these modulatory effects are well described, the binding sites for molecular partners are still largely unknown. The highly symmetrical and sleek structure of the channel makes predictions of functional moieties difficult. However, one residue repeatedly sticks out when reviewing VDAC literature. A glutamate at position 73 (E73) located on the outside of the channel facing the hydrophobic membrane environment was repeatedly proposed to be involved in channel regulation on multiple levels. Here, we review the distinct hypothesized roles of E73 and summarize the open questions around this mysterious residue.
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Affiliation(s)
- Alexander Bernhard Rister
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
- Correspondence: ; Tel.: +49-(0)89-2180-73831
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6
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Prola A, Pilot-Storck F. Cardiolipin Alterations during Obesity: Exploring Therapeutic Opportunities. BIOLOGY 2022; 11:1638. [PMID: 36358339 PMCID: PMC9687765 DOI: 10.3390/biology11111638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/31/2022] [Accepted: 11/03/2022] [Indexed: 08/13/2023]
Abstract
Cardiolipin is a specific phospholipid of the mitochondrial inner membrane that participates in many aspects of its organization and function, hence promoting proper mitochondrial ATP production. Here, we review recent data that have investigated alterations of cardiolipin in different tissues in the context of obesity and the related metabolic syndrome. Data relating perturbations of cardiolipin content or composition are accumulating and suggest their involvement in mitochondrial dysfunction in tissues from obese patients. Conversely, cardiolipin modulation is a promising field of investigation in a search for strategies for obesity management. Several ways to restore cardiolipin content, composition or integrity are emerging and may contribute to the improvement of mitochondrial function in tissues facing excessive fat storage. Inversely, reduction of mitochondrial efficiency in a controlled way may increase energy expenditure and help fight against obesity and in this perspective, several options aim at targeting cardiolipin to achieve a mild reduction of mitochondrial coupling. Far from being just a victim of the deleterious consequences of obesity, cardiolipin may ultimately prove to be a possible weapon to fight against obesity in the future.
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Affiliation(s)
- Alexandre Prola
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Fanny Pilot-Storck
- Team Relaix, INSERM, IMRB, Université Paris-Est Créteil, F-94010 Créteil, France
- EnvA, IMRB, F-94700 Maisons-Alfort, France
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7
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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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8
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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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9
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Response Predictive Markers and Synergistic Agents for Drug Repositioning of Statins in Ovarian Cancer. Pharmaceuticals (Basel) 2022; 15:ph15020124. [PMID: 35215239 PMCID: PMC8880614 DOI: 10.3390/ph15020124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 02/07/2023] Open
Abstract
In the field of drug repurposing, the use of statins for treating dyslipidemia is considered promising in ovarian cancer treatment based on epidemiological studies and basic research findings. Biomarkers should be established to identify patients who will respond to statin treatment to achieve clinical application. In the present study, we demonstrated that statins have a multifaceted mode of action in ovarian cancer and involve pathways other than protein prenylation. To identify biomarkers that predict the response to statins, we subjected ovarian cancer cells to microarray analysis and calculated Pearson’s correlation coefficients between gene expression and cell survival after statin treatment. The results showed that VDAC1 and LDLRAP1 were positively and negatively correlated with the response to statins, respectively. Histoculture drug response assays revealed that statins were effective in clinical samples. We also confirmed the synergistic effects of statins with paclitaxel and panobinostat and determined that statins are hematologically safe to administer to statin-treated mice. Future clinical trials based on the expression of the biomarkers identified in this study for repurposing statins for ovarian cancer treatment are warranted.
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10
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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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11
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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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12
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Chong K, Almsherqi ZA, Zhuo R, Deng Y. Plasmalogen-rich foods promote the formation of cubic membranes in amoeba Chaos under stress conditions. FEBS Open Bio 2021. [PMID: 34184425 PMCID: PMC8329783 DOI: 10.1002/2211-5463.13241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/11/2021] [Accepted: 06/28/2021] [Indexed: 11/11/2022] Open
Abstract
Previous studies have indicated that the ability to form cubic membrane (CM), a three-dimensional periodic structure with cubic symmetry, in amoeba (Chaos carolinense) under stress conditions depends on the type of food organism supplied before cell starvation. The significant increase in docosapentaenoic acid (DPA; C22:5n-6) during the starvation period has been reported to induce CM formation and support Chaos cell survival. In this article, we further investigated the lipid profiles of food organisms of the Chaos cells to reveal the key lipid components that might promote CM formation. Our results show that the lipids extracted from cells of the native food organism Paramecium multimicronucleatum are enriched in plasmalogens. More specifically, plasmalogen phosphatidylcholine and plasmalogen phosphatidylethanolamine might be the key lipids that trigger CM formation in Chaos cells under starvation stress conditions. Unexpectedly, CM formation in these cells is not supported when the native food organism was replaced with plasmalogen-deficit Tetrahymena pyriformis cells. Based on a previous lipidomics study on amoeba Chaos and this study on the lipid composition of its food organisms, three key lipids (plasmalogen phosphatidylcholine, plasmalogen phosphatidylethanolamine and diacyl-phosphatidylinositol) were identified and used for liposomal construction. Our in vitro study revealed the potential role of these lipids in a nonlamellar phase transition. The negative staining transmission electron microscopy data of our liposomal constructs support the notion that plasmalogens may curve the membrane, which, in turn, may facilitate membrane fusion and vesicular formation, which is crucial for membrane dynamics and trafficking.
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Affiliation(s)
- Ketpin Chong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Zakaria A Almsherqi
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ruijiang Zhuo
- School of Ophthalmology and Optometry, Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, China
| | - Yuru Deng
- School of Ophthalmology and Optometry, Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, China.,Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China
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13
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Queralt-Martín M, Bergdoll L, Teijido O, Munshi N, Jacobs D, Kuszak AJ, Protchenko O, Reina S, Magrì A, De Pinto V, Bezrukov SM, Abramson J, Rostovtseva TK. A lower affinity to cytosolic proteins reveals VDAC3 isoform-specific role in mitochondrial biology. J Gen Physiol 2021; 152:133600. [PMID: 31935282 PMCID: PMC7062508 DOI: 10.1085/jgp.201912501] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/20/2019] [Indexed: 01/30/2023] Open
Abstract
Voltage-dependent anion channel (VDAC) is the major pathway for the transport of ions and metabolites across the mitochondrial outer membrane. Among the three known mammalian VDAC isoforms, VDAC3 is the least characterized, but unique functional roles have been proposed in cellular and animal models. Yet, a high-sequence similarity between VDAC1 and VDAC3 is indicative of a similar pore-forming structure. Here, we conclusively show that VDAC3 forms stable, highly conductive voltage-gated channels that, much like VDAC1, are weakly anion selective and facilitate metabolite exchange, but exhibit unique properties when interacting with the cytosolic proteins α-synuclein and tubulin. These two proteins are known to be potent regulators of VDAC1 and induce similar characteristic blockages (on the millisecond time scale) of VDAC3, but with 10- to 100-fold reduced on-rates and altered α-synuclein blocking times, indicative of an isoform-specific function. Through cysteine scanning mutagenesis, we found that VDAC3's cysteine residues regulate its interaction with α-synuclein, demonstrating VDAC3-unique functional properties and further highlighting a general molecular mechanism for VDAC isoform-specific regulation of mitochondrial bioenergetics.
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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
| | - Lucie Bergdoll
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Oscar Teijido
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Nabill Munshi
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Daniel Jacobs
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Adam J Kuszak
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Olga Protchenko
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Simona Reina
- Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy
| | - Andrea Magrì
- Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy
| | - Vito De Pinto
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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14
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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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15
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Rosencrans WM, Aguilella VM, Rostovtseva TK, Bezrukov SM. α-Synuclein emerges as a potent regulator of VDAC-facilitated calcium transport. Cell Calcium 2021; 95:102355. [PMID: 33578201 DOI: 10.1016/j.ceca.2021.102355] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
Voltage-dependent anion channel (VDAC) is the most ubiquitous channel at the mitochondrial outer membrane, and is believed to be the pathway for calcium entering or leaving the mitochondria. Therefore, understanding the molecular mechanisms of how VDAC regulates calcium influx and efflux from the mitochondria is of particular interest for mitochondrial physiology. When the Parkinson's disease (PD) related neuronal protein, alpha-synuclein (αSyn), is added to the reconstituted VDAC, it reversibly and partially blocks VDAC conductance by its acidic C-terminal tail. Using single-molecule VDAC electrophysiology of reconstituted VDAC we now demonstrate that, at CaCl2 concentrations below 150 mM, αSyn reverses the channel's selectivity from anionic to cationic. Importantly, we find that the decrease in channel conductance upon its blockage by αSyn is hugely overcompensated by a favorable change in the electrostatic environment for calcium, making the blocked state orders-of-magnitude more selective for calcium and thus increasing its net flux. -Our findings with higher calcium concentrations also demonstrate that the phenomenon of "charge inversion" is taking place at the level of a single polypeptide chain. Measurements of ion selectivity of three VDAC isoforms in CaCl2 gradient show that VDAC3 exhibits the highest calcium permeability among them, followed by VDAC2 and VDAC1, thus pointing to isoform-dependent physiological function. Mutation of the E73 residue - VDAC1 purported calcium binding site - shows that there is no measurable effect of the mutation in either open or αSyn-blocked VDAC1 states. Our results confirm VDACs involvement in calcium signaling and reveal a new regulatory role of αSyn, with clear implications for both normal calcium signaling and PD-associated mitochondrial dysfunction.
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Affiliation(s)
- William M Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vicente M Aguilella
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, Av. Vicent Sos Baynat s/n 12071, Castellón, Spain
| | - 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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16
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Abstract
The properties of natural lipid bilayers are vital to the regulation of many membrane proteins. Scaffolded nanodiscs provide an in vitro lipid bilayer platform to host membrane proteins in an environment that approximates native lipid bilayers. However, the properties of scaffold-enclosed bilayers may depart significantly from those of bulk cellular membranes. Therefore, to improve the usefulness of nanodiscs it is essential to understand the properties of lipids restricted by scaffolds. We used computational molecular dynamics and modeling approaches to understand the effects of nanodisc size, scaffold type (DNA or protein), and hydrophobic modification of DNA scaffolds on bilayer stability and degree to which the properties of enclosed bilayers approximate bulk bilayers. With respect to achieving bulk bilayer behavior, we found that charge neutralization of DNA scaffolds was more important than the total hydrophobic content of their modifications: bilayer properties were better for scaffolds having a large number of short alkyl chains than those having fewer long alkyl chains. Further, complete charge neutralization of DNA scaffolds enabled better lipid binding, and more stable bilayers, as shown by steered molecular dynamics simulations that measured the force required to dislodge scaffolds from lipid bilayer patches. Considered together, our simulations provide a guide to the design of DNA-scaffolded nanodiscs suitable for studying membrane proteins.
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Affiliation(s)
- Vishal Maingi
- Department of Bioengineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Paul W K Rothemund
- Departments of Bioengineering, Computing + Mathematical Sciences, and Computation & Neural Systems, California Institute of Technology, Pasadena, California 91125, United States
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17
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Sander P, Gudermann T, Schredelseker J. A Calcium Guard in the Outer Membrane: Is VDAC a Regulated Gatekeeper of Mitochondrial Calcium Uptake? Int J Mol Sci 2021; 22:ijms22020946. [PMID: 33477936 PMCID: PMC7833399 DOI: 10.3390/ijms22020946] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022] Open
Abstract
Already in the early 1960s, researchers noted the potential of mitochondria to take up large amounts of Ca2+. However, the physiological role and the molecular identity of the mitochondrial Ca2+ uptake mechanisms remained elusive for a long time. The identification of the individual components of the mitochondrial calcium uniporter complex (MCUC) in the inner mitochondrial membrane in 2011 started a new era of research on mitochondrial Ca2+ uptake. Today, many studies investigate mitochondrial Ca2+ uptake with a strong focus on function, regulation, and localization of the MCUC. However, on its way into mitochondria Ca2+ has to pass two membranes, and the first barrier before even reaching the MCUC is the outer mitochondrial membrane (OMM). The common opinion is that the OMM is freely permeable to Ca2+. This idea is supported by the presence of a high density of voltage-dependent anion channels (VDACs) in the OMM, forming large Ca2+ permeable pores. However, several reports challenge this idea and describe VDAC as a regulated Ca2+ channel. In line with this idea is the notion that its Ca2+ selectivity depends on the open state of the channel, and its gating behavior can be modified by interaction with partner proteins, metabolites, or small synthetic molecules. Furthermore, mitochondrial Ca2+ uptake is controlled by the localization of VDAC through scaffolding proteins, which anchor VDAC to ER/SR calcium release channels. This review will discuss the possibility that VDAC serves as a physiological regulator of mitochondrial Ca2+ uptake in the OMM.
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Affiliation(s)
- Paulina Sander
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany; (P.S.); (T.G.)
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany; (P.S.); (T.G.)
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany; (P.S.); (T.G.)
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
- Correspondence: ; Tel.: +49-(0)89-2180-73831
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18
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Beiersdorf J, Hevesi Z, Calvigioni D, Pyszkowski J, Romanov R, Szodorai E, Lubec G, Shirran S, Botting CH, Kasper S, Guy GW, Gray R, Di Marzo V, Harkany T, Keimpema E. Adverse effects of Δ9-tetrahydrocannabinol on neuronal bioenergetics during postnatal development. JCI Insight 2020; 5:135418. [PMID: 33141759 PMCID: PMC7714410 DOI: 10.1172/jci.insight.135418] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 10/28/2020] [Indexed: 11/22/2022] Open
Abstract
Ongoing societal changes in views on the medical and recreational roles of cannabis increased the use of concentrated plant extracts with a Δ9-tetrahydrocannabinol (THC) content of more than 90%. Even though prenatal THC exposure is widely considered adverse for neuronal development, equivalent experimental data for young age cohorts are largely lacking. Here, we administered plant-derived THC (1 or 5 mg/kg) to mice daily during P5–P16 and P5–P35 and monitored its effects on hippocampal neuronal survival and specification by high-resolution imaging and iTRAQ proteomics, respectively. We found that THC indiscriminately affects pyramidal cells and both cannabinoid receptor 1+ (CB1R)+ and CB1R– interneurons by P16. THC particularly disrupted the expression of mitochondrial proteins (complexes I–IV), a change that had persisted even 4 months after the end of drug exposure. This was reflected by a THC-induced loss of membrane integrity occluding mitochondrial respiration and could be partially or completely rescued by pH stabilization, antioxidants, bypassed glycolysis, and targeting either mitochondrial soluble adenylyl cyclase or the mitochondrial voltage-dependent anion channel. Overall, THC exposure during infancy induces significant and long-lasting reorganization of neuronal circuits through mechanisms that, in large part, render cellular bioenergetics insufficient to sustain key developmental processes in otherwise healthy neurons. Repeated THC exposure in juvenile mice compromises the limbic circuitry, with life-long impairment to the respiration of neurons.
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Affiliation(s)
- Johannes Beiersdorf
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Zsofia Hevesi
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Daniela Calvigioni
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | | | - Roman Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Edit Szodorai
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gert Lubec
- Paracelsus Private Medical University, Salzburg, Austria
| | - Sally Shirran
- School of Chemistry, University of St. Andrews, St. Andrews, United Kingdom
| | | | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | | | - Roy Gray
- GW Phamaceuticals, Salisbury, Wiltshire, United Kingdom
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Pozzuoli, Italy.,Canada Excellence Research Chair, Institut Universitaire de Cardiologie et de Pneumologie de Québec and Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Québec, Canada
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria.,Department of Neuroscience, Biomedikum D7, Karolinska Institutet, Solna, Sweden
| | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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19
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VDAC Gating Thermodynamics, but Not Gating Kinetics, Are Virtually Temperature Independent. Biophys J 2020; 119:2584-2592. [PMID: 33189678 DOI: 10.1016/j.bpj.2020.10.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/06/2020] [Accepted: 10/16/2020] [Indexed: 12/17/2022] Open
Abstract
The voltage-dependent anion channel (VDAC) is the most abundant protein in the mitochondrial outer membrane and an archetypical β-barrel channel. Here, we study the effects of temperature on VDAC channels reconstituted in planar lipid membranes at the single- and multichannel levels within the 20°C to 40°C range. The temperature dependence of conductance measured on a single channel in 1 M KCl shows an increase characterized by a 10°C temperature coefficient Q10 = 1.22 ± 0.02, which exceeds that of the bathing electrolyte solution conductivity, Q10 = 1.17 ± 0.01. The rates of voltage-induced channel transition between the open and closed states measured on multichannel membranes also show statistically significant increases, with temperatures that are consistent with activation energy barriers of ∼10 ± 3 kcal/mol. At the same time, the gating thermodynamics, as characterized by the gating charge and voltage of equipartitioning, does not display any measurable temperature dependence. The two parameters stay within 3.2 ± 0.2 elementary charges and 30 ± 2 mV, respectively. Thus, whereas the channel kinetics, specifically its conductance and rates of gating response to voltage steps, demonstrates a clear increase with temperature, the conformational voltage-dependent equilibria are virtually insensitive to temperature. These results, which may be a general feature of β-barrel channel gating, suggest either an entropy-driven gating mechanism or a role for enthalpy-entropy compensation.
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20
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Rovini A, Gurnev PA, Beilina A, Queralt-Martín M, Rosencrans W, Cookson MR, Bezrukov SM, Rostovtseva TK. Molecular mechanism of olesoxime-mediated neuroprotection through targeting α-synuclein interaction with mitochondrial VDAC. Cell Mol Life Sci 2020; 77:3611-3626. [PMID: 31760463 PMCID: PMC7244372 DOI: 10.1007/s00018-019-03386-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 01/03/2023]
Abstract
An intrinsically disordered neuronal protein α-synuclein (αSyn) is known to cause mitochondrial dysfunction, contributing to loss of dopaminergic neurons in Parkinson's disease. Through yet poorly defined mechanisms, αSyn crosses mitochondrial outer membrane and targets respiratory complexes leading to bioenergetics defects. Here, using neuronally differentiated human cells overexpressing wild-type αSyn, we show that the major metabolite channel of the outer membrane, the voltage-dependent anion channel (VDAC), is a pathway for αSyn translocation into the mitochondria. Importantly, the neuroprotective cholesterol-like synthetic compound olesoxime inhibits this translocation. By applying complementary electrophysiological and biophysical approaches, we provide mechanistic insights into the interplay between αSyn, VDAC, and olesoxime. Our data suggest that olesoxime interacts with VDAC β-barrel at the lipid-protein interface thus hindering αSyn translocation through the VDAC pore and affecting VDAC voltage gating. We propose that targeting αSyn translocation through VDAC could represent a key mechanism for the development of new neuroprotective strategies.
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Affiliation(s)
- 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, 20892-0924, USA
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - 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, 20892-0924, USA
| | - Alexandra Beilina
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, 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, 20892-0924, USA
| | - William 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, 20892-0924, USA
- Colgate University, Hamilton, NY, 13346, USA
| | - Mark R Cookson
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, 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, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, 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, 20892-0924, USA.
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21
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Malik C, Ghosh S. Regulation of Single-Channel Conductance of Voltage-Dependent Anion Channel by Mercuric Chloride in a Planar Lipid Bilayer. J Membr Biol 2020; 253:357-371. [PMID: 32748041 DOI: 10.1007/s00232-020-00134-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/24/2020] [Indexed: 11/26/2022]
Abstract
The existence of mercury in various forms, e.g., elemental, organic, and inorganic has been known for decades. In any of these forms, it is poisonous to metabolism. In this, an investigation about the effect of the inorganic form of mercury, i.e., mercuric chloride (HgCl2) to the mitochondrial voltage-dependent anion channel (VDAC), has been done after isolation from the cardiac and brain tissues of Wistar rats. In vitro electrophysiology experiments were performed in Cardiolipin planar lipid bilayer membrane (BLM) to study the change in the conductance, selectivity, and gating charge of VDAC post HgCl2 treatment. A reduction in mean conductance of VDAC from 4.3 ± 0.18 to 1.66 ± 0.11 nS was observed. Further, the Gating charge calculated before (± 3.5) and after HgCl2 treatment (± 2.3) showed significant difference. Later, VDAC's behavior was studied at different concentrations of HgCl2 ranging from 0.1 μM to 1 mM. The Inhibitory concentration (IC50) was calculated from the linear regression plot. The IC50 was found to be 488.1 μM. In the asymmetrical HgCl2 (5:1), a permeability ratio of cation to anion was found to be 4.2. It is interpreted that VDAC functioning is affected due to the application of 4 mM HgCl2 and a reduction in the conductance, gating charge, and permeability of VDAC was detected. The results provide clues to HgCl2-induced toxicity mediated through VDAC in the Cardiolipin BLM.
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Affiliation(s)
- Chetan Malik
- Department of Biophysics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Subhendu Ghosh
- Department of Biophysics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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22
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Hoogerheide DP, Gurnev PA, Rostovtseva TK, Bezrukov SM. Effect of a post-translational modification mimic on protein translocation through a nanopore. NANOSCALE 2020; 12:11070-11078. [PMID: 32400834 PMCID: PMC7350168 DOI: 10.1039/d0nr01577f] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Post-translational modifications (PTMs) of proteins are recognized as crucial components of cell signaling pathways through modulating folding, altering stability, changing interactions with ligands, and, therefore, serving multiple regulatory functions. PTMs occur as covalent modifications of the protein's amino acid side chains or the length and composition of their termini. Here we study the functional consequences of PTMs for α-synuclein (αSyn) interactions with the nanopore of the voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane. PTMs were mimicked by a divalent Alexa Fluor 488 sidechain attached separately at two positions on the αSyn C-terminus. Using single-channel reconstitution into planar lipid membranes, we find that such modifications change interactions drastically in both efficiency of VDAC inhibition by αSyn and its translocation through the VDAC nanopore. Analysis of the on/off kinetics in terms of an interaction "quasipotential" allows the positions of the C-terminal modifications to be determined with an accuracy of about three residues. Moreover, our results uncover a previously unobserved mechanism by which cytosolic proteins control β-barrel channels and thus a new regulatory function for PTMs.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Philip A Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 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, 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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23
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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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24
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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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25
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Cheng WW, Budelier MM, Sugasawa Y, Bergdoll L, Queralt-Martín M, Rosencrans W, Rostovtseva TK, Chen ZW, Abramson J, Krishnan K, Covey DF, Whitelegge JP, Evers AS. Multiple neurosteroid and cholesterol binding sites in voltage-dependent anion channel-1 determined by photo-affinity labeling. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1269-1279. [PMID: 31176038 PMCID: PMC6681461 DOI: 10.1016/j.bbalip.2019.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/23/2019] [Accepted: 06/02/2019] [Indexed: 12/31/2022]
Abstract
Voltage-dependent anion channel-1 (VDAC1) is a mitochondrial porin that is implicated in cellular metabolism and apoptosis, and modulated by numerous small molecules including lipids. VDAC1 binds sterols, including cholesterol and neurosteroids such as allopregnanolone. Biochemical and computational studies suggest that VDAC1 binds multiple cholesterol molecules, but photolabeling studies have identified only a single cholesterol and neurosteroid binding site at E73. To identify all the binding sites of neurosteroids in VDAC1, we apply photo-affinity labeling using two sterol-based photolabeling reagents with complementary photochemistry: 5α-6-AziP which contains an aliphatic diazirine, and KK200 which contains a trifluoromethyl-phenyldiazirine (TPD) group. 5α-6-AziP and KK200 photolabel multiple residues within an E73 pocket confirming the presence of this site and mapping sterol orientation within this pocket. In addition, KK200 photolabels four other sites consistent with the finding that VDAC1 co-purifies with five cholesterol molecules. Both allopregnanolone and cholesterol competitively prevent photolabeling at E73 and three other sites indicating that these are common sterol binding sites shared by both neurosteroids and cholesterol. Binding at the functionally important residue E73 suggests a possible role for sterols in regulating VDAC1 signaling and interaction with partner proteins.
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Affiliation(s)
- Wayland W.L. Cheng
- Department of Anesthesiology, Washington University in St. Louis, MO 63110, USA
| | - Melissa M. Budelier
- Department of Anesthesiology, Washington University in St. Louis, MO 63110, USA,Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, MO 63110, USA
| | - Yusuke Sugasawa
- Department of Anesthesiology, Washington University in St. Louis, MO 63110, USA
| | - Lucie Bergdoll
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - 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
| | - William Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 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, Bethesda, MD 20892, USA
| | - Zi-Wei Chen
- Department of Anesthesiology, Washington University in St. Louis, MO 63110, USA,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, MO 63110, USA
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University in St. Louis, MO 63110, USA
| | - Douglas F. Covey
- Department of Anesthesiology, Washington University in St. Louis, MO 63110, USA,Department of Developmental Biology, Washington University in St. Louis, MO 63110, USA,Department of Psychiatry, Washington University in St. Louis, MO 63110, USA,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, MO 63110, USA
| | - Julian P. Whitelegge
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Alex S. Evers
- Department of Anesthesiology, Washington University in St. Louis, MO 63110, USA,Department of Developmental Biology, Washington University in St. Louis, MO 63110, USA,Department of Psychiatry, Washington University in St. Louis, MO 63110, USA,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, MO 63110, USA,Corresponding author at: Department of Anesthesiology, Washington University School of Medicine, Campus Box 8054, St. Louis, MO 63110, USA. (A.S. Evers)
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26
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Perini DA, Alcaraz A, Queralt-Martín M. Lipid Headgroup Charge and Acyl Chain Composition Modulate Closure of Bacterial β-Barrel Channels. Int J Mol Sci 2019; 20:ijms20030674. [PMID: 30764475 PMCID: PMC6386941 DOI: 10.3390/ijms20030674] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 12/14/2022] Open
Abstract
The outer membrane of Gram-negative bacteria contains β-barrel proteins that form high-conducting ion channels providing a path for hydrophilic molecules, including antibiotics. Traditionally, these proteins have been considered to exist only in an open state so that regulation of outer membrane permeability was accomplished via protein expression. However, electrophysiological recordings show that β-barrel channels respond to transmembrane voltages by characteristically switching from a high-conducting, open state, to a so-called 'closed' state, with reduced permeability and possibly exclusion of large metabolites. Here, we use the bacterial porin OmpF from E. coli as a model system to gain insight on the control of outer membrane permeability by bacterial porins through the modulation of their open state. Using planar bilayer electrophysiology, we perform an extensive study of the role of membrane lipids in the OmpF channel closure by voltage. We pay attention not only to the effects of charges in the hydrophilic lipid heads but also to the contribution of the hydrophobic tails in the lipid-protein interactions. Our results show that gating kinetics is governed by lipid characteristics so that each stage of a sequential closure is different from the previous one, probably because of intra- or intermonomeric rearrangements.
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Affiliation(s)
- D Aurora Perini
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071 Castellón, Spain.
| | - Antonio Alcaraz
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071 Castellón, Spain.
| | - 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.
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27
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Reif MM, Fischer M, Fredriksson K, Hagn F, Zacharias M. The N-Terminal Segment of the Voltage-Dependent Anion Channel: A Possible Membrane-Bound Intermediate in Pore Unbinding. J Mol Biol 2019; 431:223-243. [DOI: 10.1016/j.jmb.2018.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/11/2018] [Accepted: 09/26/2018] [Indexed: 12/25/2022]
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28
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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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29
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Weinrich M, Worcester DL. The actions of volatile anesthetics: a new perspective. Acta Crystallogr D Struct Biol 2018; 74:1169-1177. [PMID: 30605131 PMCID: PMC6317591 DOI: 10.1107/s2059798318004771] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/22/2018] [Indexed: 11/10/2022] Open
Abstract
This article reviews recent work in applying neutron and X-ray scattering towards the elucidation of the molecular mechanisms of volatile anesthetics. Experimental results on domain mixing in ternary lipid mixtures, and the influence of volatile anesthetics and hydrostatic pressure are placed in the contexts of ion-channel function and receptor trafficking at the postsynaptic density.
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30
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Srivastava SR, Zadafiya P, Mahalakshmi R. Hydrophobic Mismatch Modulates Stability and Plasticity of Human Mitochondrial VDAC2. Biophys J 2018; 115:2386-2394. [PMID: 30503532 PMCID: PMC6301912 DOI: 10.1016/j.bpj.2018.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/15/2018] [Accepted: 11/01/2018] [Indexed: 01/13/2023] Open
Abstract
The human mitochondrial outer membrane protein voltage-dependent anion channel isoform 2 (hVDAC2) is a β-barrel metabolite flux channel that is indispensable for cell survival. It is well established that physical forces imposed on a transmembrane protein by its surrounding lipid environment decide protein structure and stability. Yet, how the mitochondrial membrane and protein-lipid interplay together regulate hVDAC2 stability is unknown. Here, we combine experimental biophysical investigations of protein stability with all-atom molecular dynamics simulations to study the effect of the most abundant mitochondrial phosphocholine (PC) lipids on hVDAC2. We demonstrate experimentally that increasing the PC lipid acyl chain length from diC14:0 to diC18:0-PC has a nonlinear effect on the β-barrel. We show that protein stability is highest in diC16:0-PC, which exhibits a negative mismatch with the hVDAC2 barrel. Our simulations also reveal that structural rigidity of hVDAC2 is highest under optimal negative mismatch provided by diC16:0-PC bilayers. Further, we validate our observations by altering the physical properties of PC membranes indirectly using cholesterol. We propose that VDAC plasticity and stability in the mitochondrial outer membrane are modulated by physical properties of the bilayer.
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Affiliation(s)
- Shashank Ranjan Srivastava
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Punit Zadafiya
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India.
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31
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Bieberich E. Sphingolipids and lipid rafts: Novel concepts and methods of analysis. Chem Phys Lipids 2018; 216:114-131. [PMID: 30194926 PMCID: PMC6196108 DOI: 10.1016/j.chemphyslip.2018.08.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/20/2018] [Accepted: 08/25/2018] [Indexed: 12/12/2022]
Abstract
About twenty years ago, the functional lipid raft model of the plasma membrane was published. It took into account decades of research showing that cellular membranes are not just homogenous mixtures of lipids and proteins. Lateral anisotropy leads to assembly of membrane domains with specific lipid and protein composition regulating vesicular traffic, cell polarity, and cell signaling pathways in a plethora of biological processes. However, what appeared to be a clearly defined entity of clustered raft lipids and proteins became increasingly fluid over the years, and many of the fundamental questions about biogenesis and structure of lipid rafts remained unanswered. Experimental obstacles in visualizing lipids and their interactions hampered progress in understanding just how big rafts are, where and when they are formed, and with which proteins raft lipids interact. In recent years, we have begun to answer some of these questions and sphingolipids may take center stage in re-defining the meaning and functional significance of lipid rafts. In addition to the archetypical cholesterol-sphingomyelin raft with liquid ordered (Lo) phase and the liquid-disordered (Ld) non-raft regions of cellular membranes, a third type of microdomains termed ceramide-rich platforms (CRPs) with gel-like structure has been identified. CRPs are "ceramide rafts" that may offer some fresh view on the membrane mesostructure and answer several critical questions for our understanding of lipid rafts.
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Affiliation(s)
- Erhard Bieberich
- Department of Physiology at the University of Kentucky, Lexington, KY, United States.
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32
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Kalu N, Atsmon-Raz Y, Momben Abolfath S, Lucas L, Kenney C, Leppla SH, Tieleman DP, Nestorovich EM. Effect of late endosomal DOBMP lipid and traditional model lipids of electrophysiology on the anthrax toxin channel activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2192-2203. [PMID: 30409515 DOI: 10.1016/j.bbamem.2018.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/09/2018] [Accepted: 08/19/2018] [Indexed: 01/26/2023]
Abstract
Anthrax toxin action requires triggering of natural endocytic transport mechanisms whereby the binding component of the toxin forms channels (PA63) within endosomal limiting and intraluminal vesicle membranes to deliver the toxin's enzymatic components into the cytosol. Membrane lipid composition varies at different stages of anthrax toxin internalization, with intraluminal vesicle membranes containing ~70% of anionic bis(monoacylglycero)phosphate lipid. Using model bilayer measurements, we show that membrane lipids can have a strong effect on the anthrax toxin channel properties, including the channel-forming activity, voltage-gating, conductance, selectivity, and enzymatic factor binding. Interestingly, the highest PA63 insertion rate was observed in bis(monoacylglycero)phosphate membranes. The molecular dynamics simulation data show that the conformational properties of the channel are different in bis(monoacylglycero)phosphate compared to PC, PE, and PS lipids. The anthrax toxin protein/lipid bilayer system can be advanced as a novel robust model to directly investigate lipid influence on membrane protein properties and protein/protein interactions.
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Affiliation(s)
- Nnanya Kalu
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Yoav Atsmon-Raz
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Alberta, Canada.
| | - Sanaz Momben Abolfath
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Laura Lucas
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Clare Kenney
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Stephen H Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda 20892, MD, USA
| | - D Peter Tieleman
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Alberta, Canada
| | - Ekaterina M Nestorovich
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA.
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33
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Rostovtseva TK, Gurnev PA, Hoogerheide DP, Rovini A, Sirajuddin M, Bezrukov SM. Sequence diversity of tubulin isotypes in regulation of the mitochondrial voltage-dependent anion channel. J Biol Chem 2018; 293:10949-10962. [PMID: 29777059 PMCID: PMC6052224 DOI: 10.1074/jbc.ra117.001569] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/16/2018] [Indexed: 12/31/2022] Open
Abstract
The microtubule protein tubulin is a heterodimer comprising α/β subunits, in which each subunit features multiple isotypes in vertebrates. For example, seven α-tubulin and eight β-tubulin isotypes in the human tubulin gene family vary mostly in the length and primary sequence of the disordered anionic carboxyl-terminal tails (CTTs). The biological reason for such sequence diversity remains a topic of vigorous enquiry. Here, we demonstrate that it may be a key feature of tubulin's role in regulation of the permeability of the mitochondrial outer membrane voltage-dependent anion channel (VDAC). Using recombinant yeast α/β-tubulin constructs with α-CTTs, β-CTTs, or both from various human tubulin isotypes, we probed their interactions with VDAC reconstituted into planar lipid bilayers. A comparative study of the blockage kinetics revealed that either α-CTTs or β-CTTs block the VDAC pore and that the efficiency of blockage by individual CTTs spans 2 orders of magnitude, depending on the CTT isotype. β-Tubulin constructs, notably β3, blocked VDAC most effectively. We quantitatively described these experimental results using a physical model that accounted only for the number and distribution of charges in the CTT, and not for the interactions between specific residues on the CTT and VDAC pore. Based on these results, we speculate that the effectiveness of VDAC regulation by tubulin depends on the predominant tubulin isotype in a cell. Consequently, the fluxes of ATP/ADP through the channel could vary significantly, depending on the isotype, thus suggesting an intriguing link between VDAC regulation and the diversity of tubulin isotypes present in vertebrates.
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Affiliation(s)
- Tatiana K Rostovtseva
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924,
| | - Philip A Gurnev
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924
| | - David P Hoogerheide
- the Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, and
| | - Amandine Rovini
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924
| | | | - Sergey M Bezrukov
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924
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34
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Jaipuria G, Ukmar-Godec T, Zweckstetter M. Challenges and approaches to understand cholesterol-binding impact on membrane protein function: an NMR view. Cell Mol Life Sci 2018; 75:2137-2151. [PMID: 29520423 PMCID: PMC11105689 DOI: 10.1007/s00018-018-2789-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 01/27/2023]
Abstract
Experimental evidence for a direct role of lipids in determining the structure, dynamics, and function of membrane proteins leads to the term 'functional lipids'. In particular, the sterol molecule cholesterol modulates the activity of many membrane proteins. The precise nature of cholesterol-binding sites and the consequences of modulation of local membrane micro-viscosity by cholesterol, however, is often unknown. Here, we review the current knowledge of the interaction of cholesterol with transmembrane proteins, with a special focus on structural aspects of the interaction derived from nuclear magnetic resonance approaches. We highlight examples of the importance of cholesterol modulation of membrane protein function, discuss the specificity of cholesterol binding, and review the proposed binding motifs from a molecular perspective. We conclude with a short perspective on what could be future trends in research efforts targeted towards a better understanding of cholesterol/membrane protein interactions.
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Affiliation(s)
- Garima Jaipuria
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
| | - Tina Ukmar-Godec
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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35
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Brini M, Leanza L, Szabo I. Lipid-Mediated Modulation of Intracellular Ion Channels and Redox State: Physiopathological Implications. Antioxid Redox Signal 2018; 28:949-972. [PMID: 28679281 DOI: 10.1089/ars.2017.7215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Significance: Ion channels play an important role in the regulation of organelle function within the cell, as proven by increasing evidence pointing to a link between altered function of intracellular ion channels and different pathologies ranging from cancer to neurodegenerative diseases, ischemic damage, and lysosomal storage diseases. Recent Advances: A link between these pathologies and redox state as well as lipid homeostasis and ion channel function is in the focus of current research. Critical Issues: Ion channels are target of modulation by lipids and lipid messengers, although in most cases the mechanistic details have not been clarified yet. Ion channel function importantly impacts production of reactive oxygen species (ROS), especially in the case of mitochondria and lysosomes. ROS, in turn, may modulate the function of intracellular channels triggering thereby a feedback control under physiological conditions. If produced in excess, ROS can be harmful to lipids and may produce oxidized forms of these membrane constituents that ultimately affect ion channel function by triggering a "circulus vitiosus." Future Directions: The present review summarizes our current knowledge about the contribution of intracellular channels to oxidative stress and gives examples of how these channels are modulated by lipids and how this modulation may affect ROS production in ROS-related diseases. Future studies need to address the importance of the regulation of intracellular ion channels and related oxidative stress by lipids in various physiological and pathological contexts. Antioxid. Redox Signal. 28, 949-972.
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Affiliation(s)
- Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.,CNR Institute of Neuroscience, Padova, Italy
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36
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Kong JN, Zhu Z, Itokazu Y, Wang G, Dinkins MB, Zhong L, Lin HP, Elsherbini A, Leanhart S, Jiang X, Qin H, Zhi W, Spassieva SD, Bieberich E. Novel function of ceramide for regulation of mitochondrial ATP release in astrocytes. J Lipid Res 2018; 59:488-506. [PMID: 29321137 DOI: 10.1194/jlr.m081877] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/08/2018] [Indexed: 12/14/2022] Open
Abstract
We reported that amyloid β peptide (Aβ42) activated neutral SMase 2 (nSMase2), thereby increasing the concentration of the sphingolipid ceramide in astrocytes. Here, we show that Aβ42 induced mitochondrial fragmentation in wild-type astrocytes, but not in nSMase2-deficient cells or astrocytes treated with fumonisin B1 (FB1), an inhibitor of ceramide synthases. Unexpectedly, ceramide depletion was concurrent with rapid movements of mitochondria, indicating an unknown function of ceramide for mitochondria. Using immunocytochemistry and super-resolution microscopy, we detected ceramide-enriched and mitochondria-associated membranes (CEMAMs) that were codistributed with microtubules. Interaction of ceramide with tubulin was confirmed by cross-linking to N-[9-(3-pent-4-ynyl-3-H-diazirine-3-yl)-nonanoyl]-D-erythro-sphingosine (pacFACer), a bifunctional ceramide analog, and binding of tubulin to ceramide-linked agarose beads. Ceramide-associated tubulin (CAT) translocated from the perinuclear region to peripheral CEMAMs and mitochondria, which was prevented in nSMase2-deficient or FB1-treated astrocytes. Proximity ligation and coimmunoprecipitation assays showed that ceramide depletion reduced association of tubulin with voltage-dependent anion channel 1 (VDAC1), an interaction known to block mitochondrial ADP/ATP transport. Ceramide-depleted astrocytes contained higher levels of ATP, suggesting that ceramide-induced CAT formation leads to VDAC1 closure, thereby reducing mitochondrial ATP release, and potentially motility and resistance to Aβ42 Our data also indicate that inhibiting ceramide generation may protect mitochondria in Alzheimer's disease.
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Affiliation(s)
- Ji-Na Kong
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Zhihui Zhu
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Yutaka Itokazu
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA
| | - Guanghu Wang
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Michael B Dinkins
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA
| | - Liansheng Zhong
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY.,College of Basic Medicine, China Medical University, Shenyang, People's Republic of China
| | - Hsuan-Pei Lin
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Ahmed Elsherbini
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Silvia Leanhart
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA
| | - Xue Jiang
- Department of Physiology, University of Kentucky, Lexington, KY.,Rehabilitation Center, ShengJing Hospital of China Medical University, Shenyang, People's Republic of China
| | - Haiyan Qin
- Department of Physiology, University of Kentucky, Lexington, KY
| | - Wenbo Zhi
- Center of Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | | | - Erhard Bieberich
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA .,Department of Physiology, University of Kentucky, Lexington, KY
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37
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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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38
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Weinrich M, Worcester DL, Bezrukov SM. Lipid nanodomains change ion channel function. NANOSCALE 2017; 9:13291-13297. [PMID: 28858358 PMCID: PMC5599369 DOI: 10.1039/c7nr03926c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Signaling proteins and neurotransmitter receptors often associate with saturated chain and cholesterol-rich domains of cell membranes, also known as lipid rafts. The saturated chains and high cholesterol environment in lipid rafts can modulate protein function, but evidence for such modulation of ion channel function in lipid rafts is lacking. Here, using raft-forming model membrane systems containing cholesterol, we show that lipid lateral phase separation at the nanoscale level directly affects the dissociation kinetics of the gramicidin dimer, a model ion channel.
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Affiliation(s)
- Michael Weinrich
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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39
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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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40
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Gupta R, Ghosh S. Phosphorylation of purified mitochondrial Voltage-Dependent Anion Channel by c-Jun N-terminal Kinase-3 modifies channel voltage-dependence. BIOCHIMIE OPEN 2017; 4:78-87. [PMID: 29450145 PMCID: PMC5802065 DOI: 10.1016/j.biopen.2017.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 03/02/2017] [Indexed: 02/05/2023]
Abstract
Voltage-Dependent Anion Channel (VDAC) phosphorylated by c-Jun N-terminal Kinase-3 (JNK3) was incorporated into the bilayer lipid membrane. Single-channel electrophysiological properties of the native and the phosphorylated VDAC were compared. The open probability versus voltage curve of the native VDAC displayed symmetry around the voltage axis, whereas that of the phosphorylated VDAC showed asymmetry. This result indicates that phosphorylation by JNK3 modifies voltage-dependence of VDAC.
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Affiliation(s)
- Rajeev Gupta
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Subhendu Ghosh
- Department of Biophysics, University of Delhi South Campus, India
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41
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Zhao Z, Zhou Y, Tian Y, Li M, Dong JF, Zhang J. Cellular microparticles and pathophysiology of traumatic brain injury. Protein Cell 2017; 8:801-810. [PMID: 28466387 PMCID: PMC5676589 DOI: 10.1007/s13238-017-0414-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/13/2017] [Indexed: 01/30/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. The finding that cellular microparticles (MPs) generated by injured cells profoundly impact on pathological courses of TBI has paved the way for new diagnostic and therapeutic strategies. MPs are subcellular fragments or organelles that serve as carriers of lipids, adhesive receptors, cytokines, nucleic acids, and tissue-degrading enzymes that are unique to the parental cells. Their sub-micron sizes allow MPs to travel to areas that parental cells are unable to reach to exercise diverse biological functions. In this review, we summarize recent developments in identifying a casual role of MPs in the pathologies of TBI and suggest that MPs serve as a new class of therapeutic targets for the prevention and treatment of TBI and associated systemic complications.
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Affiliation(s)
- Zilong Zhao
- Department of Neurosurgery, Tianjin Institute of Neurology, Tianjin Medical University General Hospital, Tianjin, 300052, China.,BloodWorks Northwest Research Institute, Seattle, WA, 98102, USA
| | - Yuan Zhou
- Department of Neurosurgery, Tianjin Institute of Neurology, Tianjin Medical University General Hospital, Tianjin, 300052, China.,BloodWorks Northwest Research Institute, Seattle, WA, 98102, USA
| | - Ye Tian
- Department of Neurosurgery, Tianjin Institute of Neurology, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Min Li
- Institute of Pathology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jing-Fei Dong
- BloodWorks Northwest Research Institute, Seattle, WA, 98102, USA. .,Division of Hematology, Department of Medicine, School of Medicine, University of Washington, Seattle, WA, 98195, USA.
| | - Jianning Zhang
- Department of Neurosurgery, Tianjin Institute of Neurology, Tianjin Medical University General Hospital, Tianjin, 300052, China.
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42
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Hoogerheide DP, Noskov SY, Jacobs D, Bergdoll L, Silin V, Worcester DL, Abramson J, Nanda H, Rostovtseva TK, Bezrukov SM. Structural features and lipid binding domain of tubulin on biomimetic mitochondrial membranes. Proc Natl Acad Sci U S A 2017; 114:E3622-E3631. [PMID: 28420794 PMCID: PMC5422764 DOI: 10.1073/pnas.1619806114] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Dimeric tubulin, an abundant water-soluble cytosolic protein known primarily for its role in the cytoskeleton, is routinely found to be associated with mitochondrial outer membranes, although the structure and physiological role of mitochondria-bound tubulin are still unknown. There is also no consensus on whether tubulin is a peripheral membrane protein or is integrated into the outer mitochondrial membrane. Here the results of five independent techniques-surface plasmon resonance, electrochemical impedance spectroscopy, bilayer overtone analysis, neutron reflectometry, and molecular dynamics simulations-suggest that α-tubulin's amphipathic helix H10 is responsible for peripheral binding of dimeric tubulin to biomimetic "mitochondrial" membranes in a manner that differentiates between the two primary lipid headgroups found in mitochondrial membranes, phosphatidylethanolamine and phosphatidylcholine. The identification of the tubulin dimer orientation and membrane-binding domain represents an essential step toward our understanding of the complex mechanisms by which tubulin interacts with integral proteins of the mitochondrial outer membrane and is important for the structure-inspired design of tubulin-targeting agents.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899;
| | - Sergei Y Noskov
- Center for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4;
| | - Daniel Jacobs
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Lucie Bergdoll
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Vitalii Silin
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
| | - David L Worcester
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Institute for Stem Cell Biology and Regenerative Medicine, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, Karnataka, India
| | - Hirsh Nanda
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
| | - 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
| | - 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;
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43
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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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44
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Luévano-Martínez LA, Forni MF, Peloggia J, Watanabe IS, Kowaltowski AJ. Calorie restriction promotes cardiolipin biosynthesis and distribution between mitochondrial membranes. Mech Ageing Dev 2017; 162:9-17. [DOI: 10.1016/j.mad.2017.02.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/03/2017] [Accepted: 02/10/2017] [Indexed: 02/06/2023]
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45
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Hoogerheide DP, Gurnev PA, Rostovtseva TK, Bezrukov SM. Mechanism of α-synuclein translocation through a VDAC nanopore revealed by energy landscape modeling of escape time distributions. NANOSCALE 2017; 9:183-192. [PMID: 27905618 PMCID: PMC6298227 DOI: 10.1039/c6nr08145b] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We probe the energy landscape governing the passage of α-synuclein, a natural "diblock copolymer"-like polypeptide, through a nanoscale pore. α-Synuclein is an intrinsically disordered neuronal protein associated with Parkinson's pathology. The motion of this electrically heterogeneous polymer in the β-barrel voltage-dependent anion channel (VDAC) of the mitochondrial outer membrane strongly depends on the properties of both the charged and uncharged regions of the α-synuclein polymer. We model this motion in two ways. First, a simple Markov model accounts for the transitions of the channel between the states of different occupancy by α-synuclein. Second, the detailed energy landscape of this motion can be accounted for using a drift-diffusion framework that incorporates the α-synuclein binding energy and the free energy cost of its confinement in the VDAC pore. The models directly predict the probability of α-synuclein translocation across the mitochondrial outer membrane, with immediate implications for the physiological role of α-synuclein in regulation of mitochondrial bioenergetics. Time-resolved measurements of the electrical properties of VDAC occupied by α-synuclein reveal distinct effects of the motion of the junction separating the differently charged regions of the polymer.
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Affiliation(s)
- David P. Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Philip A. Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 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, 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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46
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Kerkhofs M, Giorgi C, Marchi S, Seitaj B, Parys JB, Pinton P, Bultynck G, Bittremieux M. Alterations in Ca 2+ Signalling via ER-Mitochondria Contact Site Remodelling in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:225-254. [PMID: 28815534 DOI: 10.1007/978-981-10-4567-7_17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inter-organellar contact sites establish microdomains for localised Ca2+-signalling events. One of these microdomains is established between the ER and the mitochondria. Importantly, the so-called mitochondria-associated ER membranes (MAMs) contain, besides structural proteins and proteins involved in lipid exchange, several Ca2+-transport systems, mediating efficient Ca2+ transfer from the ER to the mitochondria. These Ca2+ signals critically control several mitochondrial functions, thereby impacting cell metabolism, cell death and survival, proliferation and migration. Hence, the MAMs have emerged as critical signalling hubs in physiology, while their dysregulation is an important factor that drives or at least contributes to oncogenesis and tumour progression. In this book chapter, we will provide an overview of the role of the MAMs in cell function and how alterations in the MAM composition contribute to oncogenic features and behaviours.
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Affiliation(s)
- Martijn Kerkhofs
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Bruno Seitaj
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Jan B Parys
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Geert Bultynck
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium.
| | - Mart Bittremieux
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
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47
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The multiple assemblies of VDAC: from conformational heterogeneity to β-aggregation and amyloid formation. Biochem Soc Trans 2016; 44:1531-1540. [PMID: 27911736 DOI: 10.1042/bst20160114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/22/2016] [Accepted: 06/28/2016] [Indexed: 01/10/2023]
Abstract
From their cellular localisation, to their atomic structure and their involvement in mitochondrial-driven cell death, voltage-dependent anion channels (VDACs) have challenged the scientific community with enigmas and paradoxes for over four decades. VDACs form active monomer channels in lipid bilayers, but they can also organise in multimeric assemblies. What induces, regulates and/or controls the monomer-multimer dynamics at the cellular level is not known. However, these state transitions appear to be relevant for mitochondria in making life or death decisions and for driving developmental processes. This review starts with a general introduction on VDACs and continues by examining VDAC oligomerisation/aggregation in light of recent discussions on VDAC-β-amyloid interactions and their involvement in Alzheimer's disease.
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48
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Briones R, Weichbrodt C, Paltrinieri L, Mey I, Villinger S, Giller K, Lange A, Zweckstetter M, Griesinger C, Becker S, Steinem C, de Groot BL. Voltage Dependence of Conformational Dynamics and Subconducting States of VDAC-1. Biophys J 2016; 111:1223-1234. [PMID: 27653481 PMCID: PMC5034351 DOI: 10.1016/j.bpj.2016.08.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 07/17/2016] [Accepted: 08/02/2016] [Indexed: 12/21/2022] Open
Abstract
The voltage-dependent anion channel 1 (VDAC-1) is an important protein of the outer mitochondrial membrane that transports energy metabolites and is involved in apoptosis. The available structures of VDAC proteins show a wide β-stranded barrel pore, with its N-terminal α-helix (N-α) bound to its interior. Electrophysiology experiments revealed that voltage, its polarity, and membrane composition modulate VDAC currents. Experiments with VDAC-1 mutants identified amino acids that regulate the gating process. However, the mechanisms for how these factors regulate VDAC-1, and which changes they trigger in the channel, are still unknown. In this study, molecular dynamics simulations and single-channel experiments of VDAC-1 show agreement for the current-voltage relationships of an "open" channel and they also show several subconducting transient states that are more cation selective in the simulations. We observed voltage-dependent asymmetric distortions of the VDAC-1 barrel and the displacement of particular charged amino acids. We constructed conformational models of the protein voltage response and the pore changes that consistently explain the protein conformations observed at opposite voltage polarities, either in phosphatidylethanolamine or phosphatidylcholine membranes. The submicrosecond VDAC-1 voltage response shows intrinsic structural changes that explain the role of key gating amino acids and support some of the current gating hypotheses. These voltage-dependent protein changes include asymmetric barrel distortion, its interaction with the membrane, and significant displacement of N-α amino acids.
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Affiliation(s)
- Rodolfo Briones
- Computational Biomolecular Dynamics Group, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany.
| | - Conrad Weichbrodt
- Institute of Organic and Biomolecular Chemistry, University of Goettingen, Goettingen, Germany
| | - Licia Paltrinieri
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry, University of Goettingen, Goettingen, Germany
| | - Saskia Villinger
- NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Karin Giller
- NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Adam Lange
- NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Markus Zweckstetter
- NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Goettingen, Germany; Department of Neurology, University Medical Center, University of Goettingen, Goettingen, Germany
| | - Christian Griesinger
- NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Stefan Becker
- NMR-based Structural Biology, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Goettingen, Goettingen, Germany.
| | - Bert L de Groot
- Computational Biomolecular Dynamics Group, Max-Planck Institute for Biophysical Chemistry, Goettingen, Germany.
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Modulation of the voltage-dependent anion channel of mitochondria by elaidic acid. Biochem Biophys Res Commun 2016; 477:490-4. [DOI: 10.1016/j.bbrc.2016.06.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022]
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50
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Rokitskaya TI, Kotova EA, Naberezhnykh GA, Khomenko VA, Gorbach VI, Firsov AM, Zelepuga EA, Antonenko YN, Novikova OD. Single channel activity of OmpF-like porin from Yersinia pseudotuberculosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:883-91. [PMID: 26854962 DOI: 10.1016/j.bbamem.2016.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/28/2016] [Accepted: 02/04/2016] [Indexed: 11/16/2022]
Abstract
To gain a mechanistic insight in the functioning of the OmpF-like porin from Yersinia pseudotuberculosis (YOmpF), we compared the effect of pH variation on the ion channel activity of the protein in planar lipid bilayers and its binding to lipid membranes. The behavior of YOmpF channels upon acidification was similar to that previously described for Escherichia coli OmpF. In particular, a decrease in pH of the bathing solution resulted in a substantial reduction of YOmpF single channel conductance, accompanied by the emergence of subconductance states. Similar subconductance substates were elicited by the addition of lysophosphatidylcholine. This observation, made with porin channels for the first time, pointed to the relevance of lipid-protein interactions, in particular, the lipid curvature stress, to the appearance of subconductance states at acidic pH. Binding of YOmpF to membranes displayed rather modest dependence on pH, whereas the channel-forming potency of the protein tremendously decreased upon acidification.
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Affiliation(s)
- Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1/40, Moscow 119991, Russia
| | - Elena A Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1/40, Moscow 119991, Russia
| | - Gennadiy A Naberezhnykh
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100 let Vladivostoku 159, Vladivostok 690022, Russia
| | - Valentina A Khomenko
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100 let Vladivostoku 159, Vladivostok 690022, Russia
| | - Vladimir I Gorbach
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100 let Vladivostoku 159, Vladivostok 690022, Russia
| | - Alexander M Firsov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1/40, Moscow 119991, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Leninskie Gory 1/73, Moscow 119991, Russia
| | - Elena A Zelepuga
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100 let Vladivostoku 159, Vladivostok 690022, Russia
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1/40, Moscow 119991, Russia.
| | - Olga D Novikova
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Prospect 100 let Vladivostoku 159, Vladivostok 690022, Russia.
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