1
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Geng J, Khaket TP, Pan J, Li W, Zhang Y, Ping Y, Cobos Sillero MI, Lu B. Deregulation of ER-mitochondria contact formation and mitochondrial calcium homeostasis mediated by VDAC in fragile X syndrome. Dev Cell 2023; 58:597-615.e10. [PMID: 37040696 PMCID: PMC10113018 DOI: 10.1016/j.devcel.2023.03.002] [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: 02/27/2022] [Revised: 07/31/2022] [Accepted: 03/06/2023] [Indexed: 04/13/2023]
Abstract
Loss of fragile X messenger ribonucleoprotein (FMRP) causes fragile X syndrome (FXS), the most prevalent form of inherited intellectual disability. Here, we show that FMRP interacts with the voltage-dependent anion channel (VDAC) to regulate the formation and function of endoplasmic reticulum (ER)-mitochondria contact sites (ERMCSs), structures that are critical for mitochondrial calcium (mito-Ca2+) homeostasis. FMRP-deficient cells feature excessive ERMCS formation and ER-to-mitochondria Ca2+ transfer. Genetic and pharmacological inhibition of VDAC or other ERMCS components restored synaptic structure, function, and plasticity and rescued locomotion and cognitive deficits of the Drosophila dFmr1 mutant. Expressing FMRP C-terminal domain (FMRP-C), which confers FMRP-VDAC interaction, rescued the ERMCS formation and mito-Ca2+ homeostasis defects in FXS patient iPSC-derived neurons and locomotion and cognitive deficits in Fmr1 knockout mice. These results identify altered ERMCS formation and mito-Ca2+ homeostasis as contributors to FXS and offer potential therapeutic targets.
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Affiliation(s)
- Ji Geng
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tejinder Pal Khaket
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jie Pan
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wen Li
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yan Zhang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Key Laboratory of Psychotic Disorders (No. 13dz2260500), Shanghai Mental Health Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Yong Ping
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Key Laboratory of Psychotic Disorders (No. 13dz2260500), Shanghai Mental Health Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | | | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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2
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Miller AN, Houlihan PR, Matamala E, Cabezas-Bratesco D, Lee GY, Cristofori-Armstrong B, Dilan TL, Sanchez-Martinez S, Matthies D, Yan R, Yu Z, Ren D, Brauchi SE, Clapham DE. The SARS-CoV-2 accessory protein Orf3a is not an ion channel, but does interact with trafficking proteins. eLife 2023; 12:e84477. [PMID: 36695574 PMCID: PMC9910834 DOI: 10.7554/elife.84477] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
The severe acute respiratory syndrome associated coronavirus 2 (SARS-CoV-2) and SARS-CoV-1 accessory protein Orf3a colocalizes with markers of the plasma membrane, endocytic pathway, and Golgi apparatus. Some reports have led to annotation of both Orf3a proteins as viroporins. Here, we show that neither SARS-CoV-2 nor SARS-CoV-1 Orf3a form functional ion conducting pores and that the conductances measured are common contaminants in overexpression and with high levels of protein in reconstitution studies. Cryo-EM structures of both SARS-CoV-2 and SARS-CoV-1 Orf3a display a narrow constriction and the presence of a positively charged aqueous vestibule, which would not favor cation permeation. We observe enrichment of the late endosomal marker Rab7 upon SARS-CoV-2 Orf3a overexpression, and co-immunoprecipitation with VPS39. Interestingly, SARS-CoV-1 Orf3a does not cause the same cellular phenotype as SARS-CoV-2 Orf3a and does not interact with VPS39. To explain this difference, we find that a divergent, unstructured loop of SARS-CoV-2 Orf3a facilitates its binding with VPS39, a HOPS complex tethering protein involved in late endosome and autophagosome fusion with lysosomes. We suggest that the added loop enhances SARS-CoV-2 Orf3a's ability to co-opt host cellular trafficking mechanisms for viral exit or host immune evasion.
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Affiliation(s)
| | | | - Ella Matamala
- Physiology Institute and Millennium Nucleus of Ion Channel-Associated Diseases, Universidad Austral de ChileValdiviaChile
| | - Deny Cabezas-Bratesco
- Physiology Institute and Millennium Nucleus of Ion Channel-Associated Diseases, Universidad Austral de ChileValdiviaChile
| | - Gi Young Lee
- Department of Biology, University of PennsylvaniaPhiladelphiaUnited States
| | | | | | | | | | - Rui Yan
- Janelia Research CampusAshburnUnited States
| | - Zhiheng Yu
- Janelia Research CampusAshburnUnited States
| | - Dejian Ren
- Department of Biology, University of PennsylvaniaPhiladelphiaUnited States
| | - Sebastian E Brauchi
- Janelia Research CampusAshburnUnited States
- Physiology Institute and Millennium Nucleus of Ion Channel-Associated Diseases, Universidad Austral de ChileValdiviaChile
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3
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Miller AN, Houlihan PR, Matamala E, Cabezas-Bratesco D, Lee GY, Cristofori-Armstrong B, Dilan TL, Sanchez-Martinez S, Matthies D, Yan R, Yu Z, Ren D, Brauchi SE, Clapham DE. The SARS-CoV-2 accessory protein Orf3a is not an ion channel, but does interact with trafficking proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.09.02.506428. [PMID: 36263072 PMCID: PMC9580380 DOI: 10.1101/2022.09.02.506428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The severe acute respiratory syndrome associated coronavirus 2 (SARS-CoV-2) and SARS-CoV-1 accessory protein Orf3a colocalizes with markers of the plasma membrane, endocytic pathway, and Golgi apparatus. Some reports have led to annotation of both Orf3a proteins as a viroporin. Here we show that neither SARS-CoV-2 nor SARS-CoV-1 form functional ion conducting pores and that the conductances measured are common contaminants in overexpression and with high levels of protein in reconstitution studies. Cryo-EM structures of both SARS-CoV-2 and SARS-CoV-1 Orf3a display a narrow constriction and the presence of a basic aqueous vestibule, which would not favor cation permeation. We observe enrichment of the late endosomal marker Rab7 upon SARS-CoV-2 Orf3a overexpression, and co-immunoprecipitation with VPS39. Interestingly, SARS-CoV-1 Orf3a does not cause the same cellular phenotype as SARS-CoV-2 Orf3a and does not interact with VPS39. To explain this difference, we find that a divergent, unstructured loop of SARS-CoV-2 Orf3a facilitates its binding with VPS39, a HOPS complex tethering protein involved in late endosome and autophagosome fusion with lysosomes. We suggest that the added loop enhances SARS-CoV-2 Orf3a ability to co-opt host cellular trafficking mechanisms for viral exit or host immune evasion.
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4
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Zhu X, Luo L, Xiong Y, Jiang N, Wang Y, Lv Y, Xie Y. VDAC1 oligomerization may enhance DDP-induced hepatocyte apoptosis by exacerbating oxidative stress and mitochondrial DNA damage. FEBS Open Bio 2021; 12:516-522. [PMID: 34967508 PMCID: PMC8804618 DOI: 10.1002/2211-5463.13359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/09/2021] [Accepted: 12/29/2021] [Indexed: 11/20/2022] Open
Abstract
Cisplatin (DDP)‐based chemotherapy is a preferred treatment for a broad spectrum of cancers, but the precise mechanisms of its hepatotoxicity are not yet clear. Recently, the role of voltage‐dependent anion channel protein 1 (VDAC1) in mitochondrial activity and cell apoptosis has attracted much attention. Our aim was to investigate the effects of mitochondrial outer membrane protein VDAC1 oligomerization in DDP‐induced hepatocyte apoptosis. L‐02 hepatocytes were divided into 4 groups: (a) control group, (b) 4,4'diisothiocyanate‐2,2'‐disulfonic acid (DIDS; 40 μm) group, (c) DDP (5 μm) group, and (d) DDP and DIDS combination group. Cell apoptosis was tested by Annexin V/FITC assay, protein expression of caspase‐3, γH2AX and NDUFB6 were observed by western blot assay, reactive oxygen species (ROS), and mitochondrial superoxide anion radical (O2•−) were detected by DCFH‐DA and MitoSOX probe, and DNA damage was assessed by comet assay. Moreover, the activity of mitochondrial respiratory chain complex I was determined by the colorimetry method. Compared with the control group, apoptosis rate and activated cleaved‐caspase‐3 protein, ROS and O2•− generation, DNA damage marker comet tail length, and γH2AX protein level increased in the DDP treatment group (P < 0.05). Activity of mitochondrial COXI decreased after DDP treatment (P < 0.05). DIDS, as a VDAC1 oligomerization inhibitor, antagonized DDP‐induced apoptosis by diminishing oxidative stress and DNA damage and protecting mitochondrial complex protein. These results show that VDAC1 oligomerization may play an important role in DDP‐induced hepatocyte apoptosis by increasing ROS and mtDNA leakage from VDAC1 pores, exacerbating oxidative stress and mtDNA damage.
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Affiliation(s)
- Xueqin Zhu
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China
| | - Lei Luo
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China.,Changsha center for disease control and prevention
| | - Yanyan Xiong
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China
| | - Nan Jiang
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China
| | - Yurun Wang
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China
| | - Yuan Lv
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China
| | - Ying Xie
- Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, 410081, P. R. China
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5
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Wu AJ, Tong BCK, Huang AS, Li M, Cheung KH. Mitochondrial Calcium Signaling as a Therapeutic Target for Alzheimer's Disease. Curr Alzheimer Res 2021; 17:329-343. [PMID: 31820698 DOI: 10.2174/1567205016666191210091302] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 10/17/2019] [Accepted: 12/09/2019] [Indexed: 11/22/2022]
Abstract
Mitochondria absorb calcium (Ca2+) at the expense of the electrochemical gradient generated during respiration. The influx of Ca2+ into the mitochondrial matrix helps maintain metabolic function and results in increased cytosolic Ca2+ during intracellular Ca2+ signaling. Mitochondrial Ca2+ homeostasis is tightly regulated by proteins located in the inner and outer mitochondrial membranes and by the cross-talk with endoplasmic reticulum Ca2+ signals. Increasing evidence indicates that mitochondrial Ca2+ overload is a pathological phenotype associated with Alzheimer's Disease (AD). As intracellular Ca2+ dysregulation can be observed before the appearance of typical pathological hallmarks of AD, it is believed that mitochondrial Ca2+ overload may also play an important role in AD etiology. The high mitochondrial Ca2+ uptake can easily compromise neuronal functions and exacerbate AD progression by impairing mitochondrial respiration, increasing reactive oxygen species formation and inducing apoptosis. Additionally, mitochondrial Ca2+ overload can damage mitochondrial recycling via mitophagy. This review will discuss the molecular players involved in mitochondrial Ca2+ dysregulation and the pharmacotherapies that target this dysregulation. As most of the current AD therapeutics are based on amyloidopathy, tauopathy, and the cholinergic hypothesis, they achieve only symptomatic relief. Thus, determining how to reestablish mitochondrial Ca2+ homeostasis may aid in the development of novel AD therapeutic interventions.
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Affiliation(s)
- Aston J Wu
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Benjamin C-K Tong
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Alexis S Huang
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Min Li
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - King-Ho Cheung
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
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6
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Kaestner L, Bogdanova A, Egee S. Calcium Channels and Calcium-Regulated Channels in Human Red Blood Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:625-648. [PMID: 31646528 DOI: 10.1007/978-3-030-12457-1_25] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Free Calcium (Ca2+) is an important and universal signalling entity in all cells, red blood cells included. Although mature mammalian red blood cells are believed to not contain organelles as Ca2+ stores such as the endoplasmic reticulum or mitochondria, a 20,000-fold gradient based on a intracellular Ca2+ concentration of approximately 60 nM vs. an extracellular concentration of 1.2 mM makes Ca2+-permeable channels a major signalling tool of red blood cells. However, the internal Ca2+ concentration is tightly controlled, regulated and maintained primarily by the Ca2+ pumps PMCA1 and PMCA4. Within the last two decades it became evident that an increased intracellular Ca2+ is associated with red blood cell clearance in the spleen and promotes red blood cell aggregability and clot formation. In contrast to this rather uncontrolled deadly Ca2+ signals only recently it became evident, that a temporal increase in intracellular Ca2+ can also have positive effects such as the modulation of the red blood cells O2 binding properties or even be vital for brief transient cellular volume adaptation when passing constrictions like small capillaries or slits in the spleen. Here we give an overview of Ca2+ channels and Ca2+-regulated channels in red blood cells, namely the Gárdos channel, the non-selective voltage dependent cation channel, Piezo1, the NMDA receptor, VDAC, TRPC channels, CaV2.1, a Ca2+-inhibited channel novel to red blood cells and i.a. relate these channels to the molecular unknown sickle cell disease conductance Psickle. Particular attention is given to correlation of functional measurements with molecular entities as well as the physiological and pathophysiological function of these channels. This view is in constant progress and in particular the understanding of the interaction of several ion channels in a physiological context just started. This includes on the one hand channelopathies, where a mutation of the ion channel is the direct cause of the disease, like Hereditary Xerocytosis and the Gárdos Channelopathy. On the other hand it applies to red blood cell related diseases where an altered channel activity is a secondary effect like in sickle cell disease or thalassemia. Also these secondary effects should receive medical and pharmacologic attention because they can be crucial when it comes to the life-threatening symptoms of the disease.
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Affiliation(s)
- Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany. .,Experimental Physics, Saarland University, Saarbrücken, Germany.
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, Vetsuisse Faculty and the Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
| | - Stephane Egee
- CNRS, UMR8227 LBI2M, Sorbonne Université, Roscoff, France.,Laboratoire d'Excellence GR-Ex, Paris, France
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7
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Paschon V, Morena BC, Correia FF, Beltrame GR, Dos Santos GB, Cristante AF, Kihara AH. VDAC1 is essential for neurite maintenance and the inhibition of its oligomerization protects spinal cord from demyelination and facilitates locomotor function recovery after spinal cord injury. Sci Rep 2019; 9:14063. [PMID: 31575916 PMCID: PMC6773716 DOI: 10.1038/s41598-019-50506-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/04/2019] [Indexed: 02/08/2023] Open
Abstract
During the progression of the neurodegenerative process, mitochondria participates in several intercellular signaling pathways. Voltage-dependent anion-selective channel 1 (VDAC1) is a mitochondrial porin involved in the cellular metabolism and apoptosis intrinsic pathway in many neuropathological processes. In spinal cord injury (SCI), after the primary cell death, a secondary response that comprises the release of pro-inflammatory molecules triggers apoptosis, inflammation, and demyelination, often leading to the loss of motor functions. Here, we investigated the functional role of VDAC1 in the neurodegeneration triggered by SCI. We first determined that in vitro targeted ablation of VDAC1 by specific morpholino antisense nucleotides (MOs) clearly promotes neurite retraction, whereas a pharmacological blocker of VDAC1 oligomerization (4, 4′-diisothiocyanatostilbene-2, 2′-disulfonic acid, DIDS), does not cause this effect. We next determined that, after SCI, VDAC1 undergoes conformational changes, including oligomerization and N-terminal exposition, which are important steps in the triggering of apoptotic signaling. Considering this, we investigated the effects of DIDS in vivo application after SCI. Interestingly, blockade of VDAC1 oligomerization decreases the number of apoptotic cells without interfering in the neuroinflammatory response. DIDS attenuates the massive oligodendrocyte cell death, subserving undisputable motor function recovery. Taken together, our results suggest that the prevention of VDAC1 oligomerization might be beneficial for the clinical treatment of SCI.
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Affiliation(s)
- Vera Paschon
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.
| | - Beatriz Cintra Morena
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Felipe Fernandes Correia
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Giovanna Rossi Beltrame
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Gustavo Bispo Dos Santos
- Instituto de Ortopedia e Traumatologia, Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Alexandre Fogaça Cristante
- Instituto de Ortopedia e Traumatologia, Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Alexandre Hiroaki Kihara
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.
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8
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Penkauskas T, Preta G. Biological applications of tethered bilayer lipid membranes. Biochimie 2019; 157:131-141. [DOI: 10.1016/j.biochi.2018.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/19/2018] [Indexed: 12/16/2022]
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9
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Leanza L, Checchetto V, Biasutto L, Rossa A, Costa R, Bachmann M, Zoratti M, Szabo I. Pharmacological modulation of mitochondrial ion channels. Br J Pharmacol 2019; 176:4258-4283. [PMID: 30440086 DOI: 10.1111/bph.14544] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/15/2018] [Accepted: 10/22/2018] [Indexed: 12/17/2022] Open
Abstract
The field of mitochondrial ion channels has undergone a rapid development during the last three decades, due to the molecular identification of some of the channels residing in the outer and inner membranes. Relevant information about the function of these channels in physiological and pathological settings was gained thanks to genetic models for a few, mitochondria-specific channels. However, many ion channels have multiple localizations within the cell, hampering a clear-cut determination of their function by pharmacological means. The present review summarizes our current knowledge about the ins and outs of mitochondrial ion channels, with special focus on the channels that have received much attention in recent years, namely, the voltage-dependent anion channels, the permeability transition pore (also called mitochondrial megachannel), the mitochondrial calcium uniporter and some of the inner membrane-located potassium channels. In addition, possible strategies to overcome the difficulties of specifically targeting mitochondrial channels versus their counterparts active in other membranes are discussed, as well as the possibilities of modulating channel function by small peptides that compete for binding with protein interacting partners. Altogether, these promising tools along with large-scale chemical screenings set up to identify new, specific channel modulators will hopefully allow us to pinpoint the actual function of most mitochondrial ion channels in the near future and to pharmacologically affect important pathologies in which they are involved, such as neurodegeneration, ischaemic damage and cancer. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.
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Affiliation(s)
- Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy
| | | | - Lucia Biasutto
- CNR Institute of Neurosciences, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Andrea Rossa
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Roberto Costa
- Department of Biology, University of Padova, Padova, Italy
| | | | - Mario Zoratti
- CNR Institute of Neurosciences, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.,CNR Institute of Neurosciences, Department of Biomedical Sciences, University of Padova, Padova, Italy
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10
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Bachmann M, Costa R, Peruzzo R, Prosdocimi E, Checchetto V, Leanza L. Targeting Mitochondrial Ion Channels to Fight Cancer. Int J Mol Sci 2018; 19:ijms19072060. [PMID: 30011966 PMCID: PMC6073807 DOI: 10.3390/ijms19072060] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022] Open
Abstract
In recent years, several experimental evidences have underlined a new role of ion channels in cancer development and progression. In particular, mitochondrial ion channels are arising as new oncological targets, since it has been proved that most of them show an altered expression during tumor development and the pharmacological targeting of some of them have been demonstrated to be able to modulate cancer growth and progression, both in vitro as well as in vivo in pre-clinical mouse models. In this scenario, pharmacology of mitochondrial ion channels would be in the near future a new frontier for the treatment of tumors. In this review, we discuss the new advances in the field, by focusing our attention on the improvements in new drug developments to target mitochondrial ion channels.
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Affiliation(s)
| | - Roberto Costa
- Department of Biology, University of Padova, 35131 Padova, Italy.
| | - Roberta Peruzzo
- Department of Biology, University of Padova, 35131 Padova, Italy.
| | - Elena Prosdocimi
- Department of Biology, University of Padova, 35131 Padova, Italy.
| | | | - Luigi Leanza
- Department of Biology, University of Padova, 35131 Padova, Italy.
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11
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Magrì A, Reina S, De Pinto V. VDAC1 as Pharmacological Target in Cancer and Neurodegeneration: Focus on Its Role in Apoptosis. Front Chem 2018; 6:108. [PMID: 29682501 PMCID: PMC5897536 DOI: 10.3389/fchem.2018.00108] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/22/2018] [Indexed: 01/15/2023] Open
Abstract
Cancer and neurodegeneration are different classes of diseases that share the involvement of mitochondria in their pathogenesis. Whereas the high glycolytic rate (the so-called Warburg metabolism) and the suppression of apoptosis are key elements for the establishment and maintenance of cancer cells, mitochondrial dysfunction and increased cell death mark neurodegeneration. As a main actor in the regulation of cell metabolism and apoptosis, VDAC may represent the common point between these two broad families of pathologies. Located in the outer mitochondrial membrane, VDAC forms channels that control the flux of ions and metabolites across the mitochondrion thus mediating the organelle's cross-talk with the rest of the cell. Furthermore, the interaction with both pro-apoptotic and anti-apoptotic factors makes VDAC a gatekeeper for mitochondria-mediated cell death and survival signaling pathways. Unfortunately, the lack of an evident druggability of this protein, since it has no defined binding or active sites, makes the quest for VDAC interacting molecules a difficult tale. Pharmacologically active molecules of different classes have been proposed to hit cancer and neurodegeneration. In this work, we provide an exhaustive and detailed survey of all the molecules, peptides, and microRNAs that exploit VDAC in the treatment of the two examined classes of pathologies. The mechanism of action and the potential or effectiveness of each compound are discussed.
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Affiliation(s)
- Andrea Magrì
- Section of Molecular Biology, Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy.,Section of Biology and Genetics, Department of Biomedicine and Biotechnology, National Institute for Biomembranes and Biosystems, Section of Catania, Catania, Italy
| | - Simona Reina
- Section of Molecular Biology, Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy.,Section of Biology and Genetics, Department of Biomedicine and Biotechnology, National Institute for Biomembranes and Biosystems, Section of Catania, Catania, Italy
| | - Vito De Pinto
- Section of Biology and Genetics, Department of Biomedicine and Biotechnology, National Institute for Biomembranes and Biosystems, Section of Catania, Catania, Italy
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12
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Synthesis and characterization of tethered lipid assemblies for membrane protein reconstitution (Review). Biointerphases 2017; 12:04E301. [PMID: 28958150 DOI: 10.1116/1.4994299] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Biological membranes and their related molecular mechanisms are essential for all living organisms. Membranes host numerous proteins and are responsible for the exchange of molecules and ions, cell signaling, and cell compartmentation. Indeed, the plasma membrane delimits the intracellular compartment from the extracellular environment and intracellular membranes. Biological membranes also play a major role in metabolism regulation and cellular physiology (e.g., mitochondrial membranes). The elaboration of membrane based biomimetic systems allows us to reconstitute and investigate, in controlled conditions, biological events occurring at the membrane interface. A whole variety of model membrane systems have been developed in the last few decades. Among these models, supported membranes were developed on various hydrophilic supports. The use of solid supports enables the direct use of surface sensitive techniques (e.g., surface plasmon resonance, quartz crystal microbalance, and atomic force microscopy) to monitor and quantify events occurring at the membrane surface. Tethered bilayer membranes (tBLMs) could be considered as an achievement of the first solid supported membranes described by the McConnell group. Tethered bilayers on solid supports were designed to delimit an inside compartment from an outside one. They were used for measuring interactions with ligands or incorporating large membrane proteins or complexes without interference with the support. In this context, the authors developed an easy concept of versatile tBLMs assembled on amino coated substrates that are formed upon the vesicle fusion rupture process applicable to protein-free vesicles as well as proteoliposomes. The phospholipid bilayer (natural or synthetic lipids) incorporated 5% of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly ethylene glycol-N-hydroxy succinimide to ensure the anchorage of the bilayer to the amino coated surface. The conditions for the formation of tBLMs on amino-coated gold and glass were optimized for protein-free vesicles. This biomimetic membrane delimits an inside "trans" compartment separated from an outside reservoir "cis." Using this tBLM construction, the authors were interested in deciphering two complex molecular mechanisms involving membrane-associated proteins. The first one concerns two mitochondrial proteins, i.e., the porin voltage dependent anion channel (VDAC) embedded in the outer membrane and the nucleotide transporter (adenine nucleotide translocase) that interacts dynamically during mitochondrial pathophysiology. The purified VDAC porin was first reconstituted in proteoliposomes that were subsequently assembled on an amino coated support to form a biomimetic membrane. As a major result, VDAC was reconstituted in this tBLM and calcium channeling was demonstrated across the lipid bilayer. The same two-compartment biomimetic membrane design was further engineered to study the translocation mechanism of a bacterial toxin, the adenylate cyclase toxin, CyaA, from Bordetella pertussis. As a result, the authors developed an elegant in vitro translocation toolkit applicable to potentially a large panel of proteins transported across membranes.
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Liguori L, Stidder B, Alcaraz JP, Lenormand JL, Cinquin P, Martin DK. Cell-free production of VDAC directly into liposomes for integration with biomimetic membrane systems. Prep Biochem Biotechnol 2017; 46:546-51. [PMID: 26443900 DOI: 10.1080/10826068.2015.1068800] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mitochondrial voltage-dependent anion channel (VDAC) is a pivotal protein since it provides the major transport pathway between the cytosol and the mitochondrial intermembrane space and it is implicated in cell apoptosis by functioning as a gatekeeper for the trafficking of mitochondrial death molecules. VDAC is a beta-barrel channel with a large conductance, and we use it as a model transport protein for the design of biomimetic systems. To overcome the limitations of classical overexpression methods for producing and purifying membrane proteins (MPs) we describe here the use of an optimized cell-free system. In a one-step reaction VDAC is obtained directly integrated into liposomes and purified by ultracentrifugation. We then combine proteoliposomes with different bilayers models in order to validate VDAC insertion and functionality. This VDAC biomimetic model is the first example validating the use of a cell-free expression system for production of MPs into liposomes and tethered bilayers as a toolbox to build a wide range of biomimetic devices.
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Affiliation(s)
- Lavinia Liguori
- a University of Grenoble 1-Joseph Fourier/CNRS/TIMC-IMAG UMR 5525 (Equipe SyNaBi) , Grenoble , France
| | - Barry Stidder
- a University of Grenoble 1-Joseph Fourier/CNRS/TIMC-IMAG UMR 5525 (Equipe SyNaBi) , Grenoble , France
| | - Jean-Pierre Alcaraz
- a University of Grenoble 1-Joseph Fourier/CNRS/TIMC-IMAG UMR 5525 (Equipe SyNaBi) , Grenoble , France
| | - Jean-Luc Lenormand
- a University of Grenoble 1-Joseph Fourier/CNRS/TIMC-IMAG UMR 5525 (Equipe SyNaBi) , Grenoble , France
| | - Philippe Cinquin
- a University of Grenoble 1-Joseph Fourier/CNRS/TIMC-IMAG UMR 5525 (Equipe SyNaBi) , Grenoble , France
| | - Donald K Martin
- a University of Grenoble 1-Joseph Fourier/CNRS/TIMC-IMAG UMR 5525 (Equipe SyNaBi) , Grenoble , France
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Ben-Hail D, Shoshan-Barmatz V. VDAC1-interacting anion transport inhibitors inhibit VDAC1 oligomerization and apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1612-23. [DOI: 10.1016/j.bbamcr.2016.04.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 03/01/2016] [Accepted: 04/06/2016] [Indexed: 10/22/2022]
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Thinnes FP. Opening up of plasmalemma type-1 VDAC to form apoptotic "find me signal" pathways is essential in early apoptosis - evidence from the pathogenesis of cystic fibrosis resulting from failure of apoptotic cell clearance followed by sterile inflammation. Mol Genet Metab 2014; 111:439-44. [PMID: 24613483 DOI: 10.1016/j.ymgme.2014.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/03/2014] [Accepted: 02/04/2014] [Indexed: 12/11/2022]
Abstract
Cell membrane-standing type-1 VDAC is involved in cell volume regulation and thus apoptosis. The channel has been shown to figure as a pathway for osmolytes of varying classes, ATP included. An early event in apoptotic cell death is the release of "find me signals" by cells that enter the apoptotic process. ATP is one of those signals. Apoptotic cells this way attract phagocytes for an immunologically silent cell clearance. Thus, whenever apoptosis fails by a blockade of plasmalemma type-1 VDAC processes of sterile inflammation must be assumed for cell elimination. This is evident from a close look on the pathogenetic process of cystic fibrosis (CF). However, in normal airway epithelia two different anion channels cooperate to guarantee an appropriate volume of airway surface liquid (ASL) necessary for surface clearing: the cystic fibrosis conductance regulator (CFTR) and the outwardly rectifying chloride channel (ORCC) complex also called "alternate chloride channel" and under the control of the CFTR. There are arguments, that type-1 VDAC forms the channel part of the ORCC complex, and it has been shown that CFTR and type-1 VDAC co-localize in the apical membranes of human surface respiratory epithelium. In cystic fibrosis, the central cAMP-dependent regulation of ion and water transport via functional CFTR is lost. Here, CFTR molecules do not reach the apical membranes of airway epithelia anymore or work in an insufficient way, respectively. In addition, type-1 VDAC is no longer available to work as a "find me signal" pathway. In consequence, clearing away of apoptotic cells is blocked. There are experimental data on the channel characteristics of type-1 VDAC under the anion channel blocker DIDS (4,4-diisothiocyanato-stilbenedisulphonic acid) that argue in favor of this hypothesis. Together, type-1 VDAC should be kept as a "find me signal" pathway, which may give way to several classes of such signals.
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Thinnes FP. New findings concerning vertebrate porin II--on the relevance of glycine motifs of type-1 VDAC. Mol Genet Metab 2013; 108:212-24. [PMID: 23419876 DOI: 10.1016/j.ymgme.2013.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
Abstract
New findings concerning vertebrate porin part I was published in 1997, then summarizing early data and reflections regarding the molecular structure of vertebrate voltage-dependent anion-selective channels, VDAC/eukaryotic porin, and the extra-mitochondrial expression pattern of human type-1 VDAC. Meanwhile, endeavors of different laboratories confirmed and widened this beginning by encircling the function of the channels. Regarding the function of mitochondrial outer membrane-standing VDACs the channels are established parts of the intrinsic apoptotic pathway and thus therapeutic targets in studies on several diseases: cancer, Alzheimer's disease, Down Syndrome, Parkinson's disease, Amyotrophic Lateral Sclerosis, cystic fibrosis and malaria. Regarding cell membrane-integrated type-1 VDAC it has been documented by different approaches that this porin channel is engaged in cell volume regulation, trans-membrane electron transport and apoptosis. Furthermore, new data insinuate a bridging of extrinsic and intrinsic apoptotic pathways, putatively gaining relevance in Alzheimer research. Mammalian type-1 VDAC, a β-barrel, is basically built up by nineteen β-sheets connected by peptide stretches of varying lengths. The molecule also comprises an N-terminal stretch of some twenty amino acids which, according to biochemical data, traverses the channel lumen towards the cytosolic surface of outer mitochondrial membranes or the plasma lemma, respectively and works as voltage sensor in channel gating. In artificial lipid bilayers VDACs figure as anion or cation-channels, as VDACs are permeable to both cations and anions, with voltage shifts changing the relative permeability. Type-1 VDAC carries several motifs where glycine residues are in critical positions. Motifs of this type, on the on hand, are established nucleotide binding sites. On the other hand, the GxxxG motifs are also discussed as relevant peptide dimerization/aggregation/membrane perturbation motifs. Finally, GxxxG motifs bind cholesterol. Type-1 VDAC shows one such GxxxG motif at the proximal end of its N-terminal voltage sensor while amyloid Aβ peptides include three of them in series. Noteworthy, two additional may be modified versions, GxxxGxG and GxxGxxxG, are found on β-sheet 19 or 9, respectively. Recent data have allowed speculating that amyloid Aβ induces apoptosis via opening type-1 VDAC in cell membranes of hypo-metabolic neurons, a process most likely running over life time--as leaves fall from trees in the tropics--and ending in Alzheimer's disease whenever critical brain regions are affected. The expression of GxxxG motifs on either reactant under consideration is in line with this model of Alzheimer's disease pathogenesis, which clearly differs from the amyloid Aβ cascade theory, and which can, furthermore, be understood as a basic model for apoptosis induction. However, to assume randomly distributed interactions of body wide found amyloid Aβ peptides with the N-terminal voltage sensors of ubiquitously expressed cell membrane-standing human type-1 VDAC opens up a new view on Alzheimer's disease, which might even include a clue on systemic aspects of the disease. While elaborating this concept, my focus was at first only on the GxxxG motif at the proximal end of the N-terminal voltage sensor of type-1 VDAC. Here, I include a corresponding sequence stretch on the channel's β-sheet 19, too.
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Abstract
Mitochondria are implicated in many important cellular functions covering the whole life cycle from mitochondrial biogenesis to cell death. Mitochondrial homeostasis is tightly regulated, and mitochondrial dysfunction is frequently associated with severe human pathologies (eg, cardiovascular diseases, cancer, and neurodegeneration). The permeability transition pore (PTP) is an unselective voltage-dependent mitochondrial channel. Despite the extensive use of electrophysiology, biochemistry, pharmacology, and genetic invalidation in mice, the molecular identity of PTP is still unknown. Nevertheless, PTP is central to mitochondrial vital functions and can play a lethal role in many pathophysiological conditions. This review recapitulates the current knowledge of the various modes of conductance of the PTP channel and discusses their implication in the physiological roles of PTP and their regulation. Based on its involvement in normal physiology and human pathology, a better understanding of this channel and its roles remains a major goal for basic scientists and clinicians.
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Affiliation(s)
- Catherine Brenner
- INSERM UMR-S 769, LabEx LERMIT, Université de Paris-Sud, 5, Rue JB Clément, 92296 Châtenay-Malabry, France.
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Inhibition of the Mitochondrial Permeability Transition for Cytoprotection: Direct versus Indirect Mechanisms. Biochem Res Int 2012; 2012:213403. [PMID: 22675634 PMCID: PMC3364550 DOI: 10.1155/2012/213403] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 02/07/2012] [Indexed: 11/17/2022] Open
Abstract
Mitochondria are fascinating organelles, which fulfill multiple cellular functions, as diverse as energy production, fatty acid β oxidation, reactive oxygen species (ROS) production and detoxification, and cell death regulation. The coordination of these functions relies on autonomous mitochondrial processes as well as on sustained cross-talk with other organelles and/or the cytosol. Therefore, this implies a tight regulation of mitochondrial functions to ensure cell homeostasis. In many diseases (e.g., cancer, cardiopathies, nonalcoholic fatty liver diseases, and neurodegenerative diseases), mitochondria can receive harmful signals, dysfunction and then, participate to pathogenesis. They can undergo either a decrease of their bioenergetic function or a process called mitochondrial permeability transition (MPT) that can coordinate cell death execution. Many studies present evidence that protection of mitochondria limits disease progression and severity. Here, we will review recent strategies to preserve mitochondrial functions via direct or indirect mechanisms of MPT inhibition. Thus, several mitochondrial proteins may be considered for cytoprotective-targeted therapies.
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VDAC, a multi-functional mitochondrial protein regulating cell life and death. Mol Aspects Med 2010; 31:227-85. [PMID: 20346371 DOI: 10.1016/j.mam.2010.03.002] [Citation(s) in RCA: 530] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/17/2010] [Indexed: 01/22/2023]
Abstract
Research over the past decade has extended the prevailing view of the mitochondrion to include functions well beyond the generation of cellular energy. It is now recognized that mitochondria play a crucial role in cell signaling events, inter-organellar communication, aging, cell proliferation, diseases and cell death. Thus, mitochondria play a central role in the regulation of apoptosis (programmed cell death) and serve as the venue for cellular decisions leading to cell life or death. One of the mitochondrial proteins controlling cell life and death is the voltage-dependent anion channel (VDAC), also known as mitochondrial porin. VDAC, located in the mitochondrial outer membrane, functions as gatekeeper for the entry and exit of mitochondrial metabolites, thereby controlling cross-talk between mitochondria and the rest of the cell. VDAC is also a key player in mitochondria-mediated apoptosis. Thus, in addition to regulating the metabolic and energetic functions of mitochondria, VDAC appears to be a convergence point for a variety of cell survival and cell death signals mediated by its association with various ligands and proteins. In this article, we review what is known about the VDAC channel in terms of its structure, relevance to ATP rationing, Ca(2+) homeostasis, protection against oxidative stress, regulation of apoptosis, involvement in several diseases and its role in the action of different drugs. In light of our recent findings and the recently solved NMR- and crystallography-based 3D structures of VDAC1, the focus of this review will be on the central role of VDAC in cell life and death, addressing VDAC function in the regulation of mitochondria-mediated apoptosis with an emphasis on structure-function relations. Understanding structure-function relationships of VDAC is critical for deciphering how this channel can perform such a variety of functions, all important for cell life and death. This review also provides insight into the potential of VDAC1 as a rational target for new therapeutics.
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Berridge MV, Herst PM, Lawen A. Targeting mitochondrial permeability in cancer drug development. Mol Nutr Food Res 2008; 53:76-86. [DOI: 10.1002/mnfr.200700493] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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De Marchi U, Szabò I, Cereghetti GM, Hoxha P, Craigen WJ, Zoratti M. A maxi-chloride channel in the inner membrane of mammalian mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1438-48. [DOI: 10.1016/j.bbabio.2008.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 08/01/2008] [Accepted: 08/12/2008] [Indexed: 01/09/2023]
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Jones S, Martel C, Belzacq-Casagrande AS, Brenner C, Howl J. Mitoparan and target-selective chimeric analogues: membrane translocation and intracellular redistribution induces mitochondrial apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:849-63. [PMID: 18267123 DOI: 10.1016/j.bbamcr.2008.01.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 12/13/2007] [Accepted: 01/03/2008] [Indexed: 11/24/2022]
Abstract
Mastoparan, and structurally-related amphipathic peptides, may induce cell death by augmentation of necrotic and/or apoptotic pathways. To more precisely delineate cytotoxic mechanisms, we determined that [Lys(5,8)Aib(10)]mastoparan (mitoparan) specifically induces apoptosis of U373MG and ECV304 cells, as demonstrated by endonuclease and caspase-3 activation and phosphatidylserine translocation. Live cell imaging confirmed that, following translocation of the plasma membrane, mitoparan specifically co-localizes with mitochondria. Complementary studies indicated that mitoparan induces swelling and permeabilization of isolated mitochondria, through cooperation with a protein of the permeability transition pore complex VDAC, leading to the release of the apoptogenic factor, cytochrome c. N-terminal acylation of mitoparan facilitated the synthesis of chimeric peptides that incorporated target-specific address motifs including an integrin-specific RGD sequence and a Fas ligand mimetic. Significantly, these sychnologically-organised peptides demonstrated further enhanced cytotoxic potencies. We conclude that the cell penetrant, mitochondriotoxic and apoptogenic properties of mitoparan, and its chimeric analogues, offer new insights to the study and therapeutic induction of apoptosis.
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Affiliation(s)
- Sarah Jones
- Research Institute in Healthcare Science, University of Wolverhampton, Wolverhampton, UK.
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Deniaud A, Sharaf el dein O, Maillier E, Poncet D, Kroemer G, Lemaire C, Brenner C. Endoplasmic reticulum stress induces calcium-dependent permeability transition, mitochondrial outer membrane permeabilization and apoptosis. Oncogene 2007; 27:285-99. [PMID: 17700538 DOI: 10.1038/sj.onc.1210638] [Citation(s) in RCA: 443] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The accumulation of Ca2+ in the mitochondrial matrix can stimulate oxidative phosphorylation, but can also, at high Ca2+ concentrations, transmit and amplify an apoptotic signal. Here, we characterized the capacity of physiological stimuli (for example, histamine and inositol-1,4,5-triphosphate) and inducers of endoplasmic reticulum (ER) stress (for example, A23187, thapsigargin and tunicamycin) to release Ca2+ from ER stores, induce mitochondrial Ca2+ accumulation, and trigger cell death in human cervix and colon carcinoma cell lines. Sustained Ca2+ accumulation in the mitochondrial matrix induced by ER stress triggered signs of proapoptotic mitochondrial alteration, namely permeability transition, dissipation of the electrochemical potential, matrix swelling, relocalization of Bax to mitochondria and the release of cytochrome c and apoptosis-inducing factor from mitochondria. In contrast, rapid and transient accumulation of Ca2+ induced by physiological stimuli failed to promote mitochondrial permeability transition and to affect cell viability. The specificity of this apoptosis pathway was validated in cells using a panel of pharmacological agents that chelate Ca2+ (BAPTA-AM) or inhibit inositol-1,4,5-trisphosphate receptor (IP(3)R; 2-aminoethoxydiphenyl borate), voltage-dependent anion channel (VDAC) (4,4'-diisothiocyanatostilbene-2,2'-disulfonate, NADH), the permeability transition pore (cyclosporin A and bongkrekic acid), caspases (z-VAD-fmk) and protein synthesis (cycloheximide). Finally, we designed an original cell-free system in which we confronted purified mitochondria and ER vesicles, and identified IP(3)R, VDAC and the permeability transition pore as key proteins in the ER-triggered proapoptotic mitochondrial membrane permeabilization process.
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Affiliation(s)
- A Deniaud
- Université de Versailles/SQY, CNRS UMR 8159, 45, Versailles, France
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Deniaud A, Rossi C, Berquand A, Homand J, Campagna S, Knoll W, Brenner C, Chopineau J. Voltage-dependent anion channel transports calcium ions through biomimetic membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:3898-905. [PMID: 17315898 DOI: 10.1021/la063105+] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The mitochondrial outer membrane channel (VDAC), a central player in mitochondria and cell death, was reconstituted in polymer-supported phospholipid bilayers. Highly purified VDAC was first reconstituted in vesicles; channel properties and NADH-ferricyanide reductase activity were ascertained before deposition onto solid substrates. 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)-N-hydroxysuccinimide mixed vesicles containing VDAC were linked onto amine-grafted surfaces (glass and gold) and disrupted to form a VDAC-containing polymer-tethered planar bilayer. Surface plasmon spectroscopy, fluorescence microscopy, and atomic force microscopy measurements ascertained the membrane thickness, fluidity, and continuity. VDAC reconstituted in bilayers efficiently transported calcium ions and was modulable by two channel blockers, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid and l-glutamate. The novel setup may allow the study of the assembly of a polyprotein complex centered on VDAC and its role in mitochondrial biology, calcium fluxes, and apoptosis.
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Affiliation(s)
- Aurélien Deniaud
- CNRS UMR 8159, Laboratoire de Génétique et Biologie Cellulaire, Université de Versailles/St Quentin, 45 Avenue des Etats-Unis, 78035 Versailles, France
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Tarze A, Deniaud A, Le Bras M, Maillier E, Molle D, Larochette N, Zamzami N, Jan G, Kroemer G, Brenner C. GAPDH, a novel regulator of the pro-apoptotic mitochondrial membrane permeabilization. Oncogene 2006; 26:2606-20. [PMID: 17072346 DOI: 10.1038/sj.onc.1210074] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a pleiotropic enzyme that is overexpressed in apoptosis and in several human chronic pathologies. Here, we report that the protein accumulates in mitochondria during apoptosis, and induces the pro-apoptotic mitochondrial membrane permeabilization, a decisive event of the intrinsic pathway of apoptosis. GAPDH was localized by immunogold labeling and identified by matrix-assisted laser desorption/ionization-time of flight and nano liquid chromatography mass spectroscopy/mass spectroscopy in the mitochondrion of various tissues and origins. In isolated mitochondria, GAPDH can be imported and interact with the voltage-dependent anion channel (VDAC1), but not the adenine nucleotide translocase (ANT). The protein mediates a cyclosporin A-inhibitable permeability transition, characterized by a loss of the inner transmembrane potential, matrix swelling, permeabilization of the inner mitochondrial membrane and the release of two pro-apoptotic proteins, cytochrome c and apoptosis-inducing factor (AIF). This novel function of GAPDH might have implications for the understanding of mitochondrial biology, oncogenesis and apoptosis.
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Affiliation(s)
- A Tarze
- CNRS UMR 8159, Université de Versailles/SQY, Versailles, France
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Koulintchenko M, Temperley RJ, Mason PA, Dietrich A, Lightowlers RN. Natural competence of mammalian mitochondria allows the molecular investigation of mitochondrial gene expression. Hum Mol Genet 2005; 15:143-54. [PMID: 16321989 DOI: 10.1093/hmg/ddi435] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Respiration, a fundamental process in mammalian cells, requires two genomes, those of the nucleus and the mitochondrion (mtDNA). Mutations of mtDNA are being increasingly recognized in disease and may play an important role in the ageing process. Accepting the vital role of mtDNA gene products, our limited knowledge concerning the details of mitochondrial gene expression is surprising. This is, in part, due to our inability to transfect mitochondria and to manipulate their genome. There have been claims of successful DNA import into isolated organelles, but most reports lacked evidence of expression and no method has furthered our understanding of gene expression. Here, we report that mammalian mitochondria possess a natural competence for DNA import. Using five functional assays, we show imported DNA can act as templates for DNA synthesis or promoter-driven transcription, with the resultant polycistronic RNA being processed (5' and 3') and excised mt-tRNA matured. Exploiting this natural competence will allow us to explore mitochondrial gene expression in organello and provides the potential for mitochondrial transfection in vivo.
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Affiliation(s)
- Milana Koulintchenko
- Mitochondrial Research Group, Institutes of Neuroscience, University of Newcastle upon Tyne, UK
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Parfenov AS, Salnikov V, Lederer WJ, Lukyánenko V. Aqueous diffusion pathways as a part of the ventricular cell ultrastructure. Biophys J 2005; 90:1107-19. [PMID: 16284268 PMCID: PMC1367097 DOI: 10.1529/biophysj.105.071787] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The physical organization of the ventricular myocyte includes barriers for the movement of objects of varying dimensions ranging from ions to solid particles. There are two kinds of diffusion in the cell: lateral (in membranes) and aqueous. Here we examine the size constraints of aqueous diffusion pathways and discuss their impact on cellular physiology. Calibrated gold nanoparticles were used to probe the accessibility of the entire transverse-axial tubular system (TATS), the sarcoplasm, and intracellular structures. The TATS tubules, although up to 300 nm in diameter, permitted only particles </=11 nm to enter. When calibrated nanoparticles were added to permeabilized ventricular cells, particles </=11 nm were found in the sarcoplasm. The distribution of nanoparticles in the cells allowed us to conclude that 1), the TATS and the sarcoplasm are accessible only for particles </=11 nm; 2), the gaps between T-tubules and junctional sarcoplasmic reticulum (jSR), jSR and mitochondria, and intermitochondrial contacts are inaccessible for particles with physical size >3 nm; 3), the mitochondrial voltage-dependent anion channel and the nuclear pore complex in ventricular cells could not be penetrated by particles >/=6 nm; and 4), there is a difference in size clearance between transversal and longitudinal sarcoplasmic diffusional pathways.
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Affiliation(s)
- A S Parfenov
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, Maryland, USA
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Shoshan-Barmatz V, Israelson A. The voltage-dependent anion channel in endoplasmic/sarcoplasmic reticulum: characterization, modulation and possible function. J Membr Biol 2005; 204:57-66. [PMID: 16151701 DOI: 10.1007/s00232-005-0749-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 04/25/2005] [Indexed: 01/15/2023]
Abstract
In recent years, it has been recognized that there is a metabolic coupling between the cytosol, ER/SR and mitochondria. In this cross-talk, mitochondrial Ca(2+) homeostasis and ATP production and supply play a major role. The primary transporter of adenine nucleotides, Ca(2+)and other metabolites into and out of mitochondria is the voltage-dependent anion channel (VDAC) located at the outer mitochondrial membrane, at a crucial position in the cell. VDAC has been established as a key player in mitochondrial metabolite and ion signaling and it has also been proposed that VDAC is present in extramitochondrial membranes. Thus, regulation of VDAC, as the main interface between mitochondrial and cellular metabolism, by other molecules is of utmost importance. This article reviews localization and function of VDAC, and focuses on VDAC as a skeletal muscle sarcoplasmic reticulum channel. The regulation of VDAC activity by associated proteins and by inhibitors is also presented. Several aspects of the physiological relevance of VDAC to Ca(2+) homeostasis and mitochondria-mediated apoptosis will be discussed.
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Affiliation(s)
- V Shoshan-Barmatz
- Department of Life Sciences and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Abstract
We have recently demonstrated that voltage dependent anion selective channel~1 (porin, isoform 1) can function as a transplasma membrane NADH:ferricyanide-reductase. However, both the specific redox characteristics and the mechanism of electron transport in this enzyme presently remain unclear. Here we demonstrate that the redox capability of porin 1 is specific for ferricyanide as this same enzyme cannot reduce DCIP or cytochrome c in vitro. Furthermore, NADH-dependent ferricyanide reduction associated with VDAC1 is not sensitive to the anion channel inhibitors DIDS and dextran sulfate. However, this activity can be inhibited by thiol chelators, suggesting that at least one of the two cysteine groups present in VDAC1 are critical for electron transfer. We propose a model on how electron transport may occur in VDAC1.
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Affiliation(s)
- Mark A Baker
- ARC Centre of Excellence in Biotechnology and Development, Reproductive Science Group, School of Environmental and Life Science, University of Newcastle, NSW, Australia
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31
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Godbole A, Varghese J, Sarin A, Mathew MK. VDAC is a conserved element of death pathways in plant and animal systems. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1642:87-96. [PMID: 12972297 DOI: 10.1016/s0167-4889(03)00102-2] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Programmed cell death (PCD) is very much a part of plant life, although the underlying mechanisms are not so well understood as in animals. In animal cells, the voltage-dependent anion channel (VDAC), a major mitochondrial outer membrane transporter, plays an important role in apoptosis by participating in the release of intermembrane space proteins. To characterize plant PCD pathways by investigating the function of putative components in a mammalian apoptotic context, we have overexpressed a rice VDAC (osVDAC4) in the Jurkat T-cell line. Overexpression of osVDAC4 induces apoptosis, which can be blocked by Bcl-2 and the VDAC inhibitor DIDS. Modifying endogenous VDAC function by DIDS and hexokinase II (HxKII) in Jurkat cells inhibits mitochondria-mediated apoptotic pathways. Finally, we show that DIDS also abrogates heat-induced PCD in cucumber cotyledons. Our data suggest that VDAC is a conserved mitochondrial element of the death machinery in both plant and animal cells.
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Affiliation(s)
- A Godbole
- National Centre for Biological Sciences, TIFR, UAS-GKVK Campus, Bangalore 560 065, India
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32
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Wu-Pong S. Alternative interpretations of the oligonucleotide transport literature: insights from nature. Adv Drug Deliv Rev 2000; 44:59-70. [PMID: 11035198 DOI: 10.1016/s0169-409x(00)00084-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Elucidation of the mechanism of oligonucleotide (ON) cellular internalization has met an impasse at the lipid penetration stage. ON internalization is commonly regarded to involve endocytosis, yet the method by which the ON penetrates the endosome membrane remains a mystery despite more than 10 years of research by multiple laboratories. In addition, the literature regarding this topic is fraught with discrepancies and inconsistencies. Therefore, the goal of this review is to propose and illustrate the feasibility of the notion that the literature discrepancies are perhaps an indication of a complex transport mechanism involving more than one uptake pathway. Accordingly, ON- and cell-differences in uptake may be attributed to differences in the relative importance of these pathways for different cell types and ONs. An example of one such pathway is reviewed and critiqued in this communication with respect to its hypothetical role in ON uptake. Other innovative mechanisms should similarly be considered to stimulate new ideas, discussion and research in this unique and interesting field.
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Affiliation(s)
- S Wu-Pong
- Department of Pharmaceutics, Box 980533, Virginia Commonwealth University, Richmond, VA 23298, USA.
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33
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Shimizu S, Ide T, Yanagida T, Tsujimoto Y. Electrophysiological study of a novel large pore formed by Bax and the voltage-dependent anion channel that is permeable to cytochrome c. J Biol Chem 2000; 275:12321-5. [PMID: 10766872 DOI: 10.1074/jbc.275.16.12321] [Citation(s) in RCA: 256] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Bcl-2 family of proteins, consisting of anti-apoptotic and pro-apoptotic members, regulates cell death by controlling mitochondrial membrane permeability that is crucial for apoptotic signal transduction. We have recently shown that some of these proteins, such as Bcl-x(L), Bax, and Bak, directly modulate the mitochondrial voltage-dependent anion channel (VDAC) and thus regulate apoptogenic cytochrome c release and potential loss. To elucidate the molecular mechanisms of VDAC regulation by Bcl-2 family proteins, an electrophysiological study was carried out. It was found that VDAC and pro-apoptotic Bax created a large pore, with conductance levels 4- and 10-fold greater than those of the VDAC and Bax channels, respectively. Although the VDAC and Bax channels both show ion selectivity and voltage-dependent modulation of their activity, the VDAC-Bax channel had neither of their properties. Anti-apoptotic Bcl-x(L) and its BH4 oligopeptide completely closed the VDAC, in contrast to the Bax. Cytochrome c passed through a single VDAC-Bax channel but not through the VDAC or Bax channel in a planar lipid bilayer. These data provide direct evidence that VDAC forms a novel large pore together with Bax.
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Affiliation(s)
- S Shimizu
- Department of Medical Genetics, Biomedical Research Center, CREST of Japan Science and Technology Corp., 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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34
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Thinnes FP, Hellmann KP, Hellmann T, Merker R, Brockhaus-Pruchniewicz U, Schwarzer C, Walter G, Götz H, Hilschmann N. Studies on human porin XXII: cell membrane integrated human porin channels are involved in regulatory volume decrease (RVD) of HeLa cells. Mol Genet Metab 2000; 69:331-7. [PMID: 10870851 DOI: 10.1006/mgme.2000.2976] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell volume regulation receives increasing attention not only as the basis of regulatory volume increase or regulatory volume decrease (RVD) of cells in surroundings of changing osmolarity, but also appears to be relevant in cell proliferation, differentiation, and apoptosis. A central event in RVD is the opening of a volume-sensitive chloride/anion channel(s), and blocking this pathway would abolish RVD. This is shown here with monoclonal mouse anti-human type-1 porin antibodies, proving that porin is involved in this process. HeLa cells preincubated with these antibodies dramatically increase their volume within about 1 min after a hypotonic stimulus by 70 mM NaCl Ringer solution, but do not move back toward their starting volume, thus indicating abolished RVD. Corresponding effects are induced by the established anion channel inhibitor DIDS. Video camera monitoring of cell size over time was used as a direct and noninvasive approach. We had already accumulated evidence that plasmalemma integrated eukaryotic porin channels form chloride/anion channels in this cell compartment and that they are involved in cell volume regulation. Finally, the present data again demonstrate the suitability of our anti-porin antibodies in physiological studies.
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Affiliation(s)
- F P Thinnes
- Abteilung Immunchemie, Max-Planck-Institut für experimentelle Medizin, Göttingen, Germany
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35
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Thinnes FP, Hellmann KP, Hellmann T, Merker R, Schwarzer C, Walter G, Götz H, Hilschmann N. Studies on human porin XXI: gadolinium opens Up cell membrane standing porin channels making way for the osmolytes chloride or taurine-A putative approach to activate the alternate chloride channel in cystic fibrosis. Mol Genet Metab 2000; 69:240-51. [PMID: 10767179 DOI: 10.1006/mgme.2000.2968] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We recently proposed that cell-membrane-integrated vertebrate porin/voltage-dependent anion-selective channel (VDAC) forms part of the outwardly rectifying chloride channel (ORCC) complex that may be involved in volume regulation. The results we present here support this thesis. According to light scattering measurements micromolar concentrations of Gd(3+) induce cell swelling of human healthy and cystic fibrosis (CF) B-lymphocyte cell lines in isotonic Ringer solution. In high-potassium Ringer solution additional swelling is observed. Gd(3+) induces excessive cell swelling of cell lines in hypotonic Ringer solutions, containing 70 mM NaCl or 135 mM taurine, respectively. The gadolinium effect is lost when NaCl is replaced by Na-gluconate. Using video camera monitoring we show that HeLa cells also swell in micromolar concentrations of Gd(3+) in isotonic taurine Ringer solution. The dose-dependent effect of the agonist was always blocked by extracellular application of anti-human type-1 porin antibodies. Together with data on a decreasing effect of micromolar amounts of gadolinium on the voltage dependence of reconstituted human porin the results prove the involvement of porin channels in the swelling behavior in different cell lines. As a mechanism we propose that ionic gadolinium opens up plasmalemma-integrated porin channels, chloride or taurine then following their concentration gradients into the cells. Furthermore, our data argue for a single pathway for inorganic and organic osmolytes during regulatory volume decrease after cell swelling. There is indirect evidence that porin forms part of the cystic fibrosis relevant ORCC channel. Gadolinium thus may work to open the alternate chloride channel in CF.
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Affiliation(s)
- F P Thinnes
- Abteilung Immunchemie, Max-Planck-Institut für Experimentelle Medizin, Hermann-Rein-Strasse 3, Göttingen, D-37075, Germany.
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36
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Báthori G, Parolini I, Szabó I, Tombola F, Messina A, Oliva M, Sargiacomo M, De Pinto V, Zoratti M. Extramitochondrial porin: facts and hypotheses. J Bioenerg Biomembr 2000; 32:79-89. [PMID: 11768765 DOI: 10.1023/a:1005516513313] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondrial porin, or VDAC, is a pore-forming protein abundant in the outer mitochondrial membrane. Several publications have reported extramitochondrial localizations as well, but the evidence was considered insufficient by many, and the presence of porin in nonmitochondrial cellular compartments has remained in doubt for a long time. We have now obtained new data indicating that the plasma membrane of hematopoietic cells contains porin, probably located mostly in caveolae or caveolae-like domains. Porin was purified from the plasma membrane of intact cells by a procedure utilizing the membrane-impermeable labeling reagent NH-SS-biotin and streptavidin affinity chromatography, and shown to have the same properties as mitochondrial porin. A channel with properties similar to that of isolated VDAC was observed by patch-clamping intact cells. This review discusses the evidence supporting extramitochondrial localization, the putative identification of the plasma membrane porin with the "maxi" chloride channel, the hypothetical mechanisms of sorting porin to various cellular membrane structures, and its possible functions.
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Affiliation(s)
- G Báthori
- Department of Physiology, Semmelweis Medical University, Budapest, Hungary.
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37
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Reymann S, Kiafard Z, Rohm B, Strutz N, Hesse D, Kratzin HD, Zimmermann B, Thinnes FP, Hilschmann N. Purification procedure and monoclonal antibodies: two instruments for research on vertebrate porins. Anal Biochem 1999; 274:289-95. [PMID: 10527528 DOI: 10.1006/abio.1999.4265] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
On Western blots of skeletal muscle preparations of different vertebrate classes, four monoclonal anti-human type 1 porin antibodies recognize one single band of either 30.5 or 31 kDa, respectively. To confirm that it is eukaryotic porin which is labeled by the antibodies, we used a purification procedure developed for human type 1 porin for porins from skeletal muscle of shark, frog, and turkey. Applied to different mammalian species and tissues, this procedure exclusively provides type 1 porin. However, applied to shark skeletal muscle, it provides two porin isotypes in nearly equal amounts. In the case of frog skeletal muscle, the procedure provides mainly type 2 porin and a lower amount of type 1 porin. Applied to turkey skeletal muscle, the method provides exclusively type 2 porin. As demonstrated by two-dimensional Western blots, both shark and frog porin isotypes and the turkey type 2 porin are recognized by our antibodies. Furthermore, we elucidated the entire amino acid sequence of frog type 2 porin.
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Affiliation(s)
- S Reymann
- Department of Immunochemistry, Department of Molecular Neuroendocrinology, Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, Göttingen, D-37075, Germany.
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38
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Shafir I, Feng W, Shoshan-Barmataz V. Voltage-dependent anion channel proteins in synaptosomes of the torpedo electric organ: immunolocalization, purification, and characterization. J Bioenerg Biomembr 1998; 30:499-510. [PMID: 9932652 DOI: 10.1023/a:1020598315287] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study, we purified and characterized the voltage-dependent anion channel (VDAC) from the Torpedo electric organ. Using immunogold labeling, VDAC was colocalized with the voltage-gated Ca2+ channel in the synaptic plasma membrane. By immunoblot analysis, five protein bands in synaptosomes isolated from the Torpedo electric organ cross reacted with two monoclonal anti-VDAC antibody. No more than about 7 to 10% mitochondrial contains could be detected in any synaptosomal membrane preparation tested. This was estimated by comparing the specific activity in mitochondria and synaptosomes of succinate-cytochrome-c oxidoreductase and antimycin-insensitive NADH-cytochrome-c oxidoreductase activities; mitochondrial inner and outer membrane marker enzymes, respectively. [14C]DCCD (dicyclohexylcarbodiimide), which specifically label mitochondrial VDAC, labeled four 30-35 kDa protein bands that were found to interact with the anti-VDAC antibody. The distribution of the Torpedo VDAC protein bands was different among membranes isolated from various tissues. VDAC was purified from synaptosomes and a separation between two of the proteins was obtained. The two purified proteins were characterized by their single channel activity and partial amino acid sequences. Upon reconstitution into a planar lipid bilayer, the purified VDACs showed voltage-dependent channel activity with properties similar to those of purified mitochondrial VDAC. Amino acid sequence of four peptides, derived from VDAC band II, exhibited high homology to sequences present in human VDACI (98%), VDAC2 (91.8%), and VDAC3 (90%), while another peptide, derived from VDAC band III, showed lower homology to either VDAC1 (88.4%) or VDAC2 (79%). Two more peptides show high homology to the sequence present in mouse brain VDAC3 (100 and 78%). In addition, we demonstrate the translocation of ATP into synaptosomes, which is inhibited by DCCD and by the anion transport inhibitor DIDS. The possible function of VDAC in the synaptic plasma membrane is discussed.
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Affiliation(s)
- I Shafir
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, Beer Sheva, Israel
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39
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Anflous K, Blondel O, Bernard A, Khrestchatisky M, Ventura-Clapier R. Characterization of rat porin isoforms: cloning of a cardiac type-3 variant encoding an additional methionine at its putative N-terminal region. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1399:47-50. [PMID: 9714728 DOI: 10.1016/s0167-4781(98)00088-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In vivo, the outer mitochondrial membrane presents a restriction of diffusion for ADP in heart and slow twitch skeletal muscles, but not in fast twitch skeletal muscle. Mitochondrial porins constitute the main pathway for the transit of metabolites across the outer mitochondrial membrane. We decided, therefore, to characterize, by cloning, rat heart VDAC and to follow their expression in different striated muscles. We cloned three isoforms, one being HVDAC1-like porin (RVDAC1) whereas the other two are MVDAC3-like porins (RVDAC3 and RVDAC3v). These three isoforms are ubiquitously expressed among striated muscles. RVDAC3v differs from RVDAC3 by one additional amino acid, a Met, located between Val39 and Glu40 in RVDAC3 sequence. This study constitutes a first step in order to further characterize striated muscle porin isoforms.
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Affiliation(s)
- K Anflous
- Laboratoire de Cardiologie Cellulaire et Moléculaire, U-446 INSERM, Faculté de Pharmacie, Université Paris-Sud, Châtenay-Malabry, France
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40
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Guibert B, Dermietzel R, Siemen D. Large conductance channel in plasma membranes of astrocytic cells is functionally related to mitochondrial VDAC-channels. Int J Biochem Cell Biol 1998; 30:379-91. [PMID: 9611779 DOI: 10.1016/s1357-2725(97)00137-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Large conductance anion channels with similar electrophysiological characteristics were found in plasma membranes and in outer mitochondrial membranes of various cell types. Although their large conductance and their peculiar voltage dependence point to a close relation, it was questioned whether they belong to the same family. We therefore compared some biochemical features of a plasmalemmal channel with those known from the mitochondrial channel. Current events were recorded from excised patches of plasma membranes of a rat astrocytic cell line (RGCN). The underlying channels exhibited a conductance of 401 +/- 50 pS. Open probability was highest between +/- 10 mV and gradually approached zero beyond +/- 25 mV. Activity as induced by voltage ramps between +/- 40 mV appeared after a delay of up to several min. The delay could be reduced by bathing either side of the patch in an acidic Ringer solution (pH 6.2). 1 mM Al3+ increased the open time at potentials more positive than 20 mV. 10 mM dextran sulfate (MW 8000) caused reversible flickering, increasing the closed probability. 4,4'-diisothiocyanatostilbene-2,2' disulfonic acid (DIDS) also caused a reversible flickering into the closed state, reducing the apparent single channel amplitude by up to 70% at 0.5 mM DIDS. Application of 5 mM ATP resulted in reversible blockade; ATP was more effective from the outside than from the inside (blocking activity 65% vs. 16% of the patches). We conclude that the large conductance anion channel from astrocytic cells displays electrophysiological and pharmacological characteristics that resemble those of VDAC (Voltage Dependent Anion Channel) from the outer mitochondrial membrane.
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Affiliation(s)
- B Guibert
- Institut für Anatomie, Universität Regensburg, Germany
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41
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Ryerse J, Blachly-Dyson E, Forte M, Nagel B. Cloning and molecular characterization of a voltage-dependent anion-selective channel (VDAC) from Drosophila melanogaster. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1327:204-12. [PMID: 9271262 DOI: 10.1016/s0005-2736(97)00059-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A full length voltage-dependent anion-selective channel (VDAC) cDNA was cloned from Drosophila melanogaster by expression library screening using an antibody against an insect VDAC protein. The cDNA clone (denoted DmVDAC) is 1082 base pairs (bp) in length and contains an open reading frame (bp 62-907) encoding a 282 amino acid protein which has a predicted molecular mass of 30550 Da, a predicted pI of 6.98 and no cysteines. Hydrophobicity analysis suggests 15 or 16 membrane-spanning domains. The DmVDAC amino acid sequence has variable homology with VDACs from other species ranging from 62% identity with a human VDAC to 23% identity with a Dictyostelium discoideum VDAC. DmVDAC has 92% identity with the 38 conserved residues in a VDAC consensus sequence. DmVDAC was expressed in VDAC-null yeast but failed to rescue viability. DmVDAC has 88% identity at the amino acid level and 99% identity at the nucleic acid level with a recently reported D. melanogaster VDAC sequence (A. Messina et al., FEBS Lett. 384 (1996) 9-13). Homology analyses with the Messina and other VDAC sequences indicate that the amino acid differences are due to minor errors in the Messina sequence. Southern blots and chromosomal in situ hybridizations suggest a single VDAC gene occurs in the fly with a locus at 32B on the left arm of the second chromosome.
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Affiliation(s)
- J Ryerse
- Department of Pathology, St. Louis University Health Sciences Center, MO 63104, USA.
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42
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Shoshan-Barmatz V, Hadad N, Feng W, Shafir I, Orr I, Varsanyi M, Heilmeyer LM. VDAC/porin is present in sarcoplasmic reticulum from skeletal muscle. FEBS Lett 1996; 386:205-10. [PMID: 8647283 DOI: 10.1016/0014-5793(96)00442-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In this study we demonstrate the existence of a protein with properties of the voltage-dependent anion channel (VDAC) in the sarcoplasmic reticulum (SR) using multiple approaches as summarized in the following: (a) 35 and 30 kDa proteins in different SR preparations, purified from other membranal systems by Ca2+/oxalate loading and sedimentation through 55% sucrose, cross-react with four different VDAC monoclonal antibodies. (b) Amino acid sequences of three peptides derived from the SR 35 kDa protein are identical to the sequences present in VDAC1 isoform. (c) Similar to the mitochondrial VDAC, the SR protein is specifically labeled by [14C]DCCD. (d) Using a new method, a 35 kDa protein has been purified from SR and mitochondria with a higher yield for the SR. (e) Upon reconstitution into a planar lipid bilayer, the purified SR protein shows voltage-dependent channel activity with properties similar to those of the purified mitochondrial VDAC or VDAC1/porin 31HL from human B lymphocytes, and its channel activity is completely inhibited by the anion transport inhibitor DIDS and about 80% by DCCD. We also demonstrate the translocation of ATP into the SR lumen and the phosphorylation of the luminal protein sarcalumenin by this ATP. Both ATP translocation and sarcalumenin phosphorylation are inhibited by DIDS, but not by atractyloside, a blocker of the ATP/ADP exchanger. These results indicate the existence of VDAC, thought to be located exclusively in mitochondria, in the SR of skeletal muscle, and its possible involvement in ATP transport. Together with recent studies on VDAC multicompartment location and its dynamic association with enzymes and channels, our findings suggest that VDAC deserves attention and consideration as a protein contributing to various cellular functions.
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Affiliation(s)
- V Shoshan-Barmatz
- Department of Life Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
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43
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Junankar PR, Dulhunty AF, Curtis SM, Pace SM, Thinnes FP. Porin-type 1 proteins in sarcoplasmic reticulum and plasmalemma of striated muscle fibres. J Muscle Res Cell Motil 1995; 16:595-610. [PMID: 8750231 DOI: 10.1007/bf00130241] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The location of porin-type 1 proteins in mammalian striated muscle has been assessed using immunogold electron microscopy with an anti-porin 31HL monoclonal antibody as the primary antibody. Gold particles were found on the mitochondrial outer membrane, the sarcoplasmic reticulum and plasmalemma in longitudinal sections of rat and rabbit skeletal muscle and rabbit and sheep cardiac muscle. The relative densities of gold particles in the mitochondrial outer membrane, sarcoplasmic reticulum and plasmalemma were 7:3:1 in white sternomastoid muscle, for example. Skeletal and cardiac sarcoplasmic reticulum vesicles, which had been fractionated by discontinuous sucrose density centrifugation, were subjected to SDS-polyacrylamide gel electrophoresis and Western blotting. The anti-porin 31HL monoclonal antibody detected a band of relative molecular mass (M(r)) 31,000 in all muscle sarcoplasmic reticulum vesicle fractions and also in liver mitochondria. The intensity of immunostaining of the sarcoplasmic reticulum fractions was 2.5-10% that of mitochondrial outer membranes per microgram of membrane protein blotted. Contamination of the sarcoplasmic reticulum fractions by mitochondrial outer membrane was < 0.75% as determined from the specific activity of monoamine oxidase. Thus, only a small part of the porin detected in sarcoplasmic reticulum vesicles can be attributed to mitochondrial contamination. These results show that porin-type1 immunoreactivity is not restricted to mitochondria but found in the sarcoplasmic reticulum and plasmalemma of both mammalian skeletal and cardiac muscle.
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Affiliation(s)
- P R Junankar
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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44
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Defects of Mitochondrial Membrane-Bound Transport Proteins in Human Mitochondriopathies: A Biochemical Approach. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/b978-0-444-82235-2.50042-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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45
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Flörke H, Thinnes FP, Winkelbach H, Stadtmüller U, Paetzold G, Morys-Wortmann C, Hesse D, Sternbach H, Zimmermann B, Kaufmann-Kolle P. Channel active mammalian porin, purified from crude membrane fractions of human B lymphocytes and bovine skeletal muscle, reversibly binds adenosine triphosphate (ATP). BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1994; 375:513-20. [PMID: 7529026 DOI: 10.1515/bchm3.1994.375.8.513] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A new aspect of mammalian porin (mammalian VDAC = mammalian voltage-dependent anion channel) is presented: channel active VDAC binds adenosine triphosphate (ATP) in the absence of Ca2+. Channel active "Porin 31HL" or "Porin 31BM", enriched from crude membranes of human B lymphocytes or whole cell lysates of bovine skeletal muscle, respectively, was bound to a nine atoms spacer ATP-agarose at pH 7.4 or 5.0 and reeluted from the resin by 10 mM ATP disodium salt. Furthermore, channel active "Porin 31BM" was labelled by [32P]ATP in a 1:1 stoichiometric relation. Binding of ATP to human porin was confirmed by studying the interaction of the synthetic porin fragment Type-1/Ac-35, comprising the putative nucleotide binding site G Y G F G, with trinitrophenyl-ATP (TNT-ATP) by scanning fluorometry. Peptide/TNP-ATP complexes clearly show enhancement of fluorescence intensity and a spectral shift of the fluorescence maximum. In a control experiment, using a porin fragment lacking the putative nucleotide binding site, no change of fluorescence emission was observed. Further confirmation for ATP binding by human VDAC arose from an autoradiographic experimental approach: the porin fragment Type-1/Ac-35 could be labelled by [32P]ATP, while a second porin fragment ending immediately before the putative nucleotide binding site could not; nor could a synthetic non porin peptide.
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Affiliation(s)
- H Flörke
- Max-Planck-Institut für experimentelle Medizin, Abteilung Immunchemie, Göttingen, Germany
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