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Yoon Y, Lee H, Federico M, Sheu SS. Non-conventional mitochondrial permeability transition: Its regulation by mitochondrial dynamics. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148914. [PMID: 36063902 PMCID: PMC9729414 DOI: 10.1016/j.bbabio.2022.148914] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Accepted: 08/29/2022] [Indexed: 11/21/2022]
Abstract
Mitochondrial permeability transition (MPT) is a phenomenon that the inner mitochondrial membrane (IMM) loses its selective permeability, leading to mitochondrial dysfunction and cell injury. Electrophysiological evidence indicates the presence of a mega-channel commonly called permeability transition pore (PTP) whose opening is responsible for MPT. However, the molecular identity of the PTP is still under intensive investigations and debates, although cyclophilin D that is inhibited by cyclosporine A (CsA) is the established regulatory component of the PTP. PTP can also open transiently and functions as a rapid mitochondrial Ca2+ releasing mechanism. Mitochondrial fission and fusion, the main components of mitochondrial dynamics, control the number and size of mitochondria, and have been shown to play a role in regulating MPT directly or indirectly. Studies by us and others have indicated the potential existence of a form of transient MPT that is insensitive to CsA. This "non-conventional" MPT is regulated by mitochondrial dynamics and may serve a protective role possibly by decreasing the susceptibility for a frequent or sustained PTP opening; hence, it may have a therapeutic value in many disease conditions involving MPT.
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Affiliation(s)
- Yisang Yoon
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta 30912, GA, USA.
| | - Hakjoo Lee
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta 30912, GA, USA
| | - Marilen Federico
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Shey-Shing Sheu
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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2
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Lin Z, Liu F, Shi P, Song A, Huang Z, Zou D, Chen Q, Li J, Gao X. Fatty acid oxidation promotes reprogramming by enhancing oxidative phosphorylation and inhibiting protein kinase C. Stem Cell Res Ther 2018; 9:47. [PMID: 29482657 PMCID: PMC5937047 DOI: 10.1186/s13287-018-0792-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Changes in metabolic pathway preferences are key events in the reprogramming process of somatic cells to induced pluripotent stem cells (iPSCs). The optimization of metabolic conditions can enhance reprogramming; however, the detailed underlying mechanisms are largely unclear. By comparing the gene expression profiles of somatic cells, intermediate-phase cells, and iPSCs, we found that carnitine palmitoyltransferase (Cpt)1b, a rate-limiting enzyme in fatty acid oxidation, was significantly upregulated in the early stage of the reprogramming process. METHODS Mouse embryonic fibroblasts isolated from transgenic mice carrying doxycycline (Dox)-inducible Yamanaka factor constructs were used for reprogramming. Various fatty acid oxidation-related metabolites were added during the reprogramming process. Colony counting and fluorescence-activated cell sorting (FACS) were used to calculate reprogramming efficiency. Fatty acid oxidation-related metabolites were measured by liquid chromatography-mass spectrometry. Seahorse was used to measure the level of oxidative phosphorylation. RESULTS We found that overexpression of cpt1b enhanced reprogramming efficiency. Furthermore, palmitoylcarnitine or acetyl-CoA, the primary and final products of Cpt1-mediated fatty acid oxidation, also promoted reprogramming. In the early reprogramming process, fatty acid oxidation upregulated oxidative phosphorylation and downregulated protein kinase C activity. Inhibition of protein kinase C also promoted reprogramming. CONCLUSION We demonstrated that fatty acid oxidation promotes reprogramming by enhancing oxidative phosphorylation and inhibiting protein kinase C activity in the early stage of the reprogramming process. This study reveals that fatty acid oxidation is crucial for the reprogramming efficiency.
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Affiliation(s)
- Zhaoyu Lin
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Collaborative Innovation Center of Genetics and Development, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing, Jiangsu, 210061, China.
| | - Fei Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu, 210093, China
| | - Peiliang Shi
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Collaborative Innovation Center of Genetics and Development, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing, Jiangsu, 210061, China
| | - Anying Song
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Collaborative Innovation Center of Genetics and Development, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing, Jiangsu, 210061, China
| | - Zan Huang
- Jiangsu Province Key Laboratory of Gastrointestinal Nutrition and Animal Health, Nanjing Agriculture University, 1 Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Dayuan Zou
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Collaborative Innovation Center of Genetics and Development, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing, Jiangsu, 210061, China
| | - Qin Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Collaborative Innovation Center of Genetics and Development, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing, Jiangsu, 210061, China
| | - Jianxin Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu, 210093, China
| | - Xiang Gao
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Collaborative Innovation Center of Genetics and Development, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing, Jiangsu, 210061, China
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3
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Andrienko TN, Pasdois P, Pereira GC, Ovens MJ, Halestrap AP. The role of succinate and ROS in reperfusion injury - A critical appraisal. J Mol Cell Cardiol 2017; 110:1-14. [PMID: 28689004 PMCID: PMC5678286 DOI: 10.1016/j.yjmcc.2017.06.016] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/14/2017] [Accepted: 06/30/2017] [Indexed: 12/20/2022]
Abstract
We critically assess the proposal that succinate-fuelled reverse electron flow (REF) drives mitochondrial matrix superoxide production from Complex I early in reperfusion, thus acting as a key mediator of ischemia/reperfusion (IR) injury. Real-time surface fluorescence measurements of NAD(P)H and flavoprotein redox state suggest that conditions are unfavourable for REF during early reperfusion. Furthermore, rapid loss of succinate accumulated during ischemia can be explained by its efflux rather than oxidation. Moreover, succinate accumulation during ischemia is not attenuated by ischemic preconditioning (IP) despite powerful cardioprotection. In addition, measurement of intracellular reactive oxygen species (ROS) during reperfusion using surface fluorescence and mitochondrial aconitase activity detected major increases in ROS only after mitochondrial permeability transition pore (mPTP) opening was first detected. We conclude that mPTP opening is probably triggered initially by factors other than ROS, including increased mitochondrial [Ca2+]. However, IP only attenuates [Ca2+] increases later in reperfusion, again after initial mPTP opening, implying that IP regulates mPTP opening through additional mechanisms. One such is mitochondria-bound hexokinase 2 (HK2) which dissociates from mitochondria during ischemia in control hearts but not those subject to IP. Indeed, there is a strong correlation between the extent of HK2 loss from mitochondria during ischemia and infarct size on subsequent reperfusion. Mechanisms linking HK2 dissociation to mPTP sensitisation remain to be fully established but several related processes have been implicated including VDAC1 oligomerisation, the stability of contact sites between the inner and outer membranes, cristae morphology, Bcl-2 family members and mitochondrial fission proteins such as Drp1.
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Affiliation(s)
- Tatyana N Andrienko
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Philippe Pasdois
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Gonçalo C Pereira
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Matthew J Ovens
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Andrew P Halestrap
- School of Biochemistry and The Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
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4
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Mitochondrial Calcium Uptake in Activation of the Permeability Transition Pore and Cell Death. MOLECULAR BASIS FOR MITOCHONDRIAL SIGNALING 2017. [DOI: 10.1007/978-3-319-55539-3_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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5
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Di Bartolomeo F, Wagner A, Daum G. Cell biology, physiology and enzymology of phosphatidylserine decarboxylase. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:25-38. [PMID: 27650064 DOI: 10.1016/j.bbalip.2016.09.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/02/2016] [Accepted: 09/10/2016] [Indexed: 12/17/2022]
Abstract
Phosphatidylethanolamine is one of the most abundant phospholipids whose major amounts are formed by phosphatidylserine decarboxylases (PSD). Here we provide a comprehensive description of different types of PSDs in the different kingdoms of life. In eukaryotes, type I PSDs are mitochondrial enzymes, whereas other PSDs are localized to other cellular compartments. We describe the role of mitochondrial Psd1 proteins, their function, enzymology, biogenesis, assembly into mitochondria and their contribution to phospholipid homeostasis in much detail. We also discuss briefly the cellular physiology and the enzymology of Psd2. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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Affiliation(s)
- Francesca Di Bartolomeo
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
| | - Ariane Wagner
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria.
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6
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Carnitine palmitoyltransferase 1C: From cognition to cancer. Prog Lipid Res 2015; 61:134-48. [PMID: 26708865 DOI: 10.1016/j.plipres.2015.11.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/18/2015] [Accepted: 11/23/2015] [Indexed: 11/21/2022]
Abstract
Carnitine palmitoyltransferase 1 (CPT1) C was the last member of the CPT1 family of genes to be discovered. CPT1A and CPT1B were identified as the gate-keeper enzymes for the entry of long-chain fatty acids (as carnitine esters) into mitochondria and their further oxidation, and they show differences in their kinetics and tissue expression. Although CPT1C exhibits high sequence similarity to CPT1A and CPT1B, it is specifically expressed in neurons (a cell-type that does not use fatty acids as fuel to any major extent), it is localized in the endoplasmic reticulum of cells, and it has minimal CPT1 catalytic activity with l-carnitine and acyl-CoA esters. The lack of an easily measurable biological activity has hampered attempts to elucidate the cellular and physiological role of CPT1C but has not diminished the interest of the biomedical research community in this CPT1 isoform. The observations that CPT1C binds malonyl-CoA and long-chain acyl-CoA suggest that it is a sensor of lipid metabolism in neurons, where it appears to impact ceramide and triacylglycerol (TAG) metabolism. CPT1C global knock-out mice show a wide range of brain disorders, including impaired cognition and spatial learning, motor deficits, and a deregulation in food intake and energy homeostasis. The first disease-causing CPT1C mutation was recently described in humans, with Cpt1c being identified as the gene causing hereditary spastic paraplegia. The putative role of CPT1C in the regulation of complex-lipid metabolism is supported by the observation that it is highly expressed in certain virulent tumor cells, conferring them resistance to glucose- and oxygen-deprivation. Therefore, CPT1C may be a promising target in the treatment of cancer. Here we review the molecular, biochemical, and structural properties of CPT1C and discuss its potential roles in brain function, and cancer.
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7
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Martinez F, Olvera-Sanchez S, Esparza-Perusquia M, Gomez-Chang E, Flores-Herrera O. Multiple functions of syncytiotrophoblast mitochondria. Steroids 2015; 103:11-22. [PMID: 26435077 DOI: 10.1016/j.steroids.2015.09.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 09/16/2015] [Accepted: 09/27/2015] [Indexed: 12/17/2022]
Abstract
The human placenta plays a central role in pregnancy, and the syncytiotrophoblast cells are the main components of the placenta that support the relationship between the mother and fetus, in apart through the production of progesterone. In this review, the metabolic processes performed by syncytiotrophoblast mitochondria associated with placental steroidogenesis are described. The metabolism of cholesterol, specifically how this steroid hormone precursor reaches the mitochondria, and its transformation into progesterone are reviewed. The role of nucleotides in steroidogenesis, as well as the mechanisms associated with signal transduction through protein phosphorylation and dephosphorylation of proteins is discussed. Finally, topics that require further research are identified, including the need for new techniques to study the syncytiotrophoblast in situ using non-invasive methods.
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Affiliation(s)
- Federico Martinez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico.
| | - Sofia Olvera-Sanchez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
| | - Mercedes Esparza-Perusquia
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
| | - Erika Gomez-Chang
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
| | - Oscar Flores-Herrera
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
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8
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Halestrap AP, Pereira GC, Pasdois P. The role of hexokinase in cardioprotection - mechanism and potential for translation. Br J Pharmacol 2014; 172:2085-100. [PMID: 25204670 PMCID: PMC4386983 DOI: 10.1111/bph.12899] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 08/21/2014] [Accepted: 08/28/2014] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial permeability transition pore (mPTP) opening plays a critical role in cardiac reperfusion injury and its prevention is cardioprotective. Tumour cell mitochondria usually have high levels of hexokinase isoform 2 (HK2) bound to their outer mitochondrial membranes (OMM) and HK2 binding to heart mitochondria has also been implicated in resistance to reperfusion injury. HK2 dissociates from heart mitochondria during ischaemia, and the extent of this correlates with the infarct size on reperfusion. Here we review the mechanisms and regulations of HK2 binding to mitochondria and how this inhibits mPTP opening and consequent reperfusion injury. Major determinants of HK2 dissociation are the elevated glucose‐6‐phosphate concentrations and decreased pH in ischaemia. These are modulated by the myriad of signalling pathways implicated in preconditioning protocols as a result of a decrease in pre‐ischaemic glycogen content. Loss of mitochondrial HK2 during ischaemia is associated with permeabilization of the OMM to cytochrome c, which leads to greater reactive oxygen species production and mPTP opening during reperfusion. Potential interactions between HK2 and OMM proteins associated with mitochondrial fission (e.g. Drp1) and apoptosis (B‐cell lymphoma 2 family members) in these processes are examined. Also considered is the role of HK2 binding in stabilizing contact sites between the OMM and the inner membrane. Breakage of these during ischaemia is proposed to facilitate cytochrome c loss during ischaemia while increasing mPTP opening and compromising cellular bioenergetics during reperfusion. We end by highlighting the many unanswered questions and discussing the potential of modulating mitochondrial HK2 binding as a pharmacological target. Linked Articles This article is part of a themed section on Conditioning the Heart – Pathways to Translation. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue‐8
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Affiliation(s)
- Andrew P Halestrap
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Bristol, UK
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9
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Halestrap AP, Richardson AP. The mitochondrial permeability transition: a current perspective on its identity and role in ischaemia/reperfusion injury. J Mol Cell Cardiol 2014; 78:129-41. [PMID: 25179911 DOI: 10.1016/j.yjmcc.2014.08.018] [Citation(s) in RCA: 310] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 08/21/2014] [Accepted: 08/24/2014] [Indexed: 12/29/2022]
Abstract
The mitochondrial permeability transition pore (MPTP) is a non-specific pore that opens in the inner mitochondrial membrane (IMM) when matrix [Ca(2+)] is high, especially when accompanied by oxidative stress, high [Pi] and adenine nucleotide depletion. Such conditions occur during ischaemia and subsequent reperfusion, when MPTP opening is known to occur and cause irreversible damage to the heart. Matrix cyclophilin D facilitates MPTP opening and is the target of its inhibition by cyclosporin A that is cardioprotective. Less certainty exists over the composition of the pore itself, with structural and/or regulatory roles proposed for the adenine nucleotide translocase, the phosphate carrier and the FoF1 ATP synthase. Here we critically review the supporting data for the role of each and suggest that they may interact with each other through their bound cardiolipin to form the ATP synthasome. We propose that under conditions favouring MPTP opening, calcium-triggered conformational changes in these proteins may perturb the interface between them generating the pore. Proteins associated with the outer mitochondrial membrane (OMM), such as members of the Bcl-2 family and hexokinase (HK), whilst not directly involved in pore formation, may regulate MPTP opening through interactions between OMM and IMM proteins at "contact sites". Recent evidence suggests that cardioprotective protocols such as preconditioning inhibit MPTP opening at reperfusion by preventing the loss of mitochondrial bound HK2 that stabilises these contact sites. Contact site breakage both sensitises the MPTP to [Ca(2+)] and facilitates cytochrome c loss from the intermembrane space leading to greater ROS production and further MPTP opening. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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Affiliation(s)
- Andrew P Halestrap
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
| | - Andrew P Richardson
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
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10
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Datler C, Pazarentzos E, Mahul-Mellier AL, Chaisaklert W, Hwang MS, Osborne F, Grimm S. CKMT1 regulates the mitochondrial permeability transition pore in a process that provides evidence for alternative forms of the complex. J Cell Sci 2014; 127:1816-28. [PMID: 24522192 PMCID: PMC3986677 DOI: 10.1242/jcs.140467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 01/08/2014] [Indexed: 12/23/2022] Open
Abstract
The permeability transition pore (PT-pore) mediates cell death through the dissipation of the mitochondrial membrane potential (ΔΨm). Because the exact composition of the PT-pore is controversial, it is crucial to investigate the actual molecular constituents and regulators of this complex. We found that mitochondrial creatine kinase-1 (CKMT1) is a universal and functionally necessary gatekeeper of the PT-pore, as its depletion induces mitochondrial depolarization and apoptotic cell death. This can be inhibited efficiently by bongkrekic acid, a compound that is widely used to inhibit the PT-pore. However, when the 'classical' PT-pore subunits cyclophilin D and VDAC1 are pharmacologically inhibited or their expression levels reduced, mitochondrial depolarization by CKMT1 depletion remains unaffected. At later stages of drug-induced apoptosis, CKMT1 levels are reduced, suggesting that CKMT1 downregulation acts to reinforce the commitment of cells to apoptosis. A novel high-molecular-mass CKMT1 complex that is distinct from the known CKMT1 octamer disintegrates upon treatment with cytotoxic drugs, concomitant with mitochondrial depolarization. Our study provides evidence that CKMT1 is a key regulator of the PT-pore through a complex that is distinct from the classical PT-pore.
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Affiliation(s)
| | | | | | | | | | | | - Stefan Grimm
- Division of Experimental Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
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11
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Horvath SE, Daum G. Lipids of mitochondria. Prog Lipid Res 2013; 52:590-614. [PMID: 24007978 DOI: 10.1016/j.plipres.2013.07.002] [Citation(s) in RCA: 610] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 07/31/2013] [Indexed: 01/06/2023]
Abstract
A unique organelle for studying membrane biochemistry is the mitochondrion whose functionality depends on a coordinated supply of proteins and lipids. Mitochondria are capable of synthesizing several lipids autonomously such as phosphatidylglycerol, cardiolipin and in part phosphatidylethanolamine, phosphatidic acid and CDP-diacylglycerol. Other mitochondrial membrane lipids such as phosphatidylcholine, phosphatidylserine, phosphatidylinositol, sterols and sphingolipids have to be imported. The mitochondrial lipid composition, the biosynthesis and the import of mitochondrial lipids as well as the regulation of these processes will be main issues of this review article. Furthermore, interactions of lipids and mitochondrial proteins which are highly important for various mitochondrial processes will be discussed. Malfunction or loss of enzymes involved in mitochondrial phospholipid biosynthesis lead to dysfunction of cell respiration, affect the assembly and stability of the mitochondrial protein import machinery and cause abnormal mitochondrial morphology or even lethality. Molecular aspects of these processes as well as diseases related to defects in the formation of mitochondrial membranes will be described.
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Affiliation(s)
- Susanne E Horvath
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
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12
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Crepaldi CR, Vitale PAM, Tesch AC, Laure HJ, Rosa JC, de Cerqueira César M. Application of 2D BN/SDS-PAGE coupled with mass spectrometry for identification of VDAC-associated protein complexes related to mitochondrial binding sites for type I brain hexokinase. Mitochondrion 2013; 13:823-30. [PMID: 23719229 DOI: 10.1016/j.mito.2013.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 02/27/2013] [Accepted: 05/14/2013] [Indexed: 11/25/2022]
Abstract
Two types of binding sites for hexokinase, designated as Type A or Type B sites, have been shown to coexist on brain mitochondria. The ratio of these sites varies between species. HK1 attaches by reversibly binding to the voltage dependent anion channel (VDAC). Regarding the nature of hexokinase binding sites, we investigated if it was linked to distinct VDAC interactomes. We approached this question by 2D BN/SDS-PAGE of mitochondria, followed by mass spectrometry. Our results are consistent with the possibility that the ratio of Type A/Type B sites is due to differential VDAC interactions in bovine and rat neuronal cells.
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Affiliation(s)
- Carla Rossini Crepaldi
- Department of Basic Sciences, School of Animal Science and Food Engineering, University of São Paulo, Pirassununga, Brazil
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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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14
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Lustgarten MS, Bhattacharya A, Muller FL, Jang YC, Shimizu T, Shirasawa T, Richardson A, Van Remmen H. Complex I generated, mitochondrial matrix-directed superoxide is released from the mitochondria through voltage dependent anion channels. Biochem Biophys Res Commun 2012; 422:515-21. [PMID: 22613204 DOI: 10.1016/j.bbrc.2012.05.055] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 05/11/2012] [Indexed: 02/07/2023]
Abstract
Mitochondrial complex I has previously been shown to release superoxide exclusively towards the mitochondrial matrix, whereas complex III releases superoxide to both the matrix and the cytosol. Superoxide produced at complex III has been shown to exit the mitochondria through voltage dependent anion channels (VDAC). To test whether complex I-derived, mitochondrial matrix-directed superoxide can be released to the cytosol, we measured superoxide generation in mitochondria isolated from wild type and from mice genetically altered to be deficient in MnSOD activity (TnIFastCreSod2(fl/fl)). Under experimental conditions that produce superoxide primarily by complex I (glutamate/malate plus rotenone, GM+R), MnSOD-deficient mitochondria release ∼4-fold more superoxide than mitochondria isolated from wild type mice. Exogenous CuZnSOD completely abolished the EPR-derived GM+R signal in mitochondria isolated from both genotypes, evidence that confirms mitochondrial superoxide release. Addition of the VDAC inhibitor DIDS significantly reduced mitochondrial superoxide release (∼75%) in mitochondria from either genotype respiring on GM+R. Conversely, inhibition of potential inner membrane sites of superoxide exit, including the matrix face of the mitochondrial permeability transition pore and the inner membrane anion channel did not reduce mitochondrial superoxide release in the presence of GM+R in mitochondria isolated from either genotype. These data support the concept that complex I-derived mitochondrial superoxide release does indeed occur and that the majority of this release occurs through VDACs.
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Affiliation(s)
- Michael S Lustgarten
- The Sam and Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, USA
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15
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McCarron JG, Olson ML, Chalmers S. Mitochondrial regulation of cytosolic Ca²⁺ signals in smooth muscle. Pflugers Arch 2012; 464:51-62. [PMID: 22555917 DOI: 10.1007/s00424-012-1108-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/11/2012] [Indexed: 11/25/2022]
Abstract
The cytosolic Ca²⁺ concentration ([Ca²⁺]c) controls virtually every activity of smooth muscle, including contraction, migration, transcription, division and apoptosis. These processes may be activated by large (>10 μM) amplitude [Ca²⁺]c increases, which occur in small restricted regions of the cell or by smaller (<1 μM) amplitude changes throughout the bulk cytoplasm. Mitochondria contribute to the regulation of these signals by taking up Ca²⁺. However, mitochondria's reported low affinity for Ca²⁺ is thought to require the organelle to be positioned close to ion channels and within a microdomain of high [Ca²⁺]. In cultured smooth muscle, mitochondria are highly dynamic structures but in native smooth muscle mitochondria are immobile, apparently strategically positioned organelles that regulate the upstroke and amplitude of IP₃-evoked Ca²⁺ signals and IP₃ receptor (IP₃R) cluster activity. These observations suggest mitochondria are positioned within the high [Ca²⁺] microdomain arising from an IP₃R cluster to exert significant local control of channel activity. On the other hand, neither the upstroke nor amplitude of voltage-dependent Ca²⁺ entry is modulated by mitochondria; rather, it is the declining phase of the transient that is regulated by the organelle. Control of the declining phase of the transient requires a high mitochondrial affinity for Ca²⁺ to enable uptake to occur over the normal physiological Ca²⁺ range (<1 μM). Thus, in smooth muscle, mitochondria regulate Ca²⁺ signals exerting effects over a large range of [Ca²⁺] (∼200 nM to at least tens of micromolar) to provide a wide dynamic range in the control of Ca²⁺ signals.
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Affiliation(s)
- John G McCarron
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, John Arbuthnott Building, 161 Cathedral Street, Glasgow, G4 0NR, UK.
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16
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Jenei ZA, Warren GZL, Hasan M, Zammit VA, Dixon AM. Packing of transmembrane domain 2 of carnitine palmitoyltransferase-1A affects oligomerization and malonyl-CoA sensitivity of the mitochondrial outer membrane protein. FASEB J 2011; 25:4522-30. [PMID: 21917985 DOI: 10.1096/fj.11-192005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The purpose of this study was to investigate the sequence-dependence of oligomerization of transmembrane domain 2 (TM2) of rat carnitine palmitoyltransferase 1A (rCPT1A), to elucidate the role of this domain in the function of the full-length enzyme. Oligomerization of TM2 was studied qualitatively using complementary genetic assays that facilitate measurement of helix-helix interactions in the Escherichia coli inner membrane, and multiple quantitative biophysical methods. The effects of TM2-mutations on oligomerization and malonyl-CoA inhibition of the full-length enzyme (expressed in the yeast Pichia pastoris) were quantified. Changes designed to disrupt close-packing of the GXXXG(A) motifs reduced the oligomeric state of the corresponding TM2 peptides from hexamer to trimer (or lower), a reduction also observed on mutation of the TM2 sequence in the full-length enzyme. Disruption of these GXXXG(A) motifs had a parallel effect on the malonyl-CoA sensitivity of rCPT1A, reducing the IC(50) from 30.3 ± 5.0 to 3.0 ± 0.6 μM. For all measurements, wild-type rCPT1A was used as a control alongside various appropriate (e.g., molecular mass) standards. Our results suggest that sequence-determined, TM2-mediated oligomerization is likely to be involved in the modulation of malonyl-CoA inhibition of CPT1A in response to short- and long-term changes in protein-protein and protein-lipid interactions that occur in vivo.
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Affiliation(s)
- Zsuzsanna A Jenei
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
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17
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García-Pérez C, Schneider TG, Hajnóczky G, Csordás G. Alignment of sarcoplasmic reticulum-mitochondrial junctions with mitochondrial contact points. Am J Physiol Heart Circ Physiol 2011; 301:H1907-15. [PMID: 21856920 DOI: 10.1152/ajpheart.00397.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Propagation of ryanodine receptor (RyR2)-derived Ca(2+) signals to the mitochondrial matrix supports oxidative ATP production or facilitates mitochondrial apoptosis in cardiac muscle. Ca(2+) transfer likely occurs locally at focal associations of the sarcoplasmic reticulum (SR) and mitochondria, which are secured by tethers. The outer mitochondrial membrane and inner mitochondrial membrane (OMM and IMM, respectively) also form tight focal contacts (contact points) that are enriched in voltage-dependent anion channels, the gates of OMM for Ca(2+). Contact points could offer the shortest Ca(2+) transfer route to the matrix; however, their alignment with the SR-OMM associations remains unclear. Here, in rat heart we have studied the distribution of mitochondria-associated SR in submitochondrial membrane fractions and evaluated the colocalization of SR-OMM associations with contact points using transmission electron microscopy. In a sucrose gradient designed for OMM purification, biochemical assays revealed lighter fractions enriched in OMM only and heavier fractions containing OMM, IMM, and SR markers. Pure OMM fractions were enriched in mitofusin 2, an ~80 kDa mitochondrial fusion protein and SR-mitochondrial tether candidate, whereas in fractions of OMM + IMM + SR, a lighter (~50 kDa) band detected by antibodies raised against the NH(2) terminus of mitofusin 2 was dominating. Transmission electron microscopy revealed mandatory presence of contact points at the junctional SR-mitochondrial interface versus a random presence along matching SR-free OMM segments. For each SR-mitochondrial junction at least one tether was attached to contact points. These data establish the contact points as anchorage sites for the SR-mitochondrial physical coupling. Close coupling of the SR, OMM, and IMM is likely to provide a favorable spatial arrangement for local ryanodine receptor-mitochondrial Ca(2+) signaling.
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Affiliation(s)
- Cecília García-Pérez
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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18
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Lipskaya TY, Voinova VV. Mitochondrial nucleoside diphosphate kinase: Mode of interaction with the outer mitochondrial membrane and proportion of catalytic activity functionally coupled to oxidative phosphorylation. BIOCHEMISTRY (MOSCOW) 2011; 73:321-31. [DOI: 10.1134/s0006297908030139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Hall PF. Actions of Corticotropin on the Adrenal Cortex: Biochemistry and Cell Biology. Compr Physiol 2011. [DOI: 10.1002/cphy.cp070404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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20
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Contribution of Potassium in Human Placental Steroidogenesis. Placenta 2010; 31:860-6. [DOI: 10.1016/j.placenta.2010.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/04/2010] [Accepted: 07/17/2010] [Indexed: 11/22/2022]
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21
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Colquhoun A. Lipids, mitochondria and cell death: implications in neuro-oncology. Mol Neurobiol 2010; 42:76-88. [PMID: 20429043 DOI: 10.1007/s12035-010-8134-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 04/05/2010] [Indexed: 12/31/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) are known to inhibit cell proliferation of many tumour types both in vitro and in vivo. Their capacity to interfere with cell proliferation has been linked to their induction of reactive oxygen species (ROS) production in tumour tissues leading to cell death through apoptosis. However, the exact mechanisms of action of PUFAs are far from clear, particularly in brain tumours. The loss of bound hexokinase from the mitochondrial voltage-dependent anion channel has been directly related to loss of protection from apoptosis, and PUFAs can induce this loss of bound hexokinase in tumour cells. Tumour cells overexpressing Akt activity, including gliomas, are sensitised to ROS damage by the Akt protein and may be good targets for chemotherapeutic agents, which produce ROS, such as PUFAs. Cardiolipin peroxidation may be an initial event in the release of cytochrome c from the mitochondria, and enriching cardiolipin with PUFA acyl chains may lead to increased peroxidation and therefore an increase in apoptosis. A better understanding of the metabolism of fatty acids and eicosanoids in primary brain tumours such as gliomas and their influence on energy balance will be fundamental to the possible targeting of mitochondria in tumour treatment.
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Affiliation(s)
- Alison Colquhoun
- Laboratory of Tumour Cell Metabolism, Department of Cell and Developmental Biology, Biomedical Sciences Institute, University of São Paulo, Avenida Prof. Lineu Prestes 1524, CEP 05508-900, São Paulo, SP, Brazil.
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22
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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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Lipskaya TY, Voinova VV. Reversibility of nucleoside diphosphate kinase solubilization from the surface of the outer mitochondrial membrane. BIOCHEMISTRY (MOSCOW) 2009; 74:578-87. [PMID: 19538133 DOI: 10.1134/s0006297909050149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It was found that in medium with low ionic strength nucleoside diphosphate kinase (NDPK) solubilization from the outer membrane of liver mitochondria could be partially reversed by the addition of 3.3 mM MgCl2. Complete rebinding of the enzyme after the addition of MgCl2 was observed when the mitochondrial washing and storage medium contained leupeptin, an inhibitor of cathepsins. It was demonstrated that leupeptin and another inhibitor of cysteine proteinases, E-64, do not influence the rate of NDPK solubilization as well as its solubilized and membrane-associated activity. We conclude that NDPK becomes sensitive to proteolysis only after its solubilization; proteolysis does not affect the part of the enzyme molecule that is responsible for catalysis. After solubilization of NDPK in the absence of leupeptin, cathepsins damage sites of its binding on the membranes. The rate of the enzyme solubilization is dependent on the pH of the storage medium (pH 6.0-8.0); it decreases with increase in pH. It was shown that in the medium with high ionic strength, MgCl2 does not reverse pH-dependent NDPK solubilization, but solubilization could be reversed by increase in medium pH in the presence of E-64 and BSA. The physiological importance of these results is discussed.
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Affiliation(s)
- T Yu Lipskaya
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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24
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Vernoux N, Maniti O, Marcillat O, Vial C, Granjon T. Mitochondrial creatine kinase interaction with heterogeneous monolayers: Effect on lipid lateral organization. Biochimie 2009; 91:752-64. [DOI: 10.1016/j.biochi.2009.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 03/20/2009] [Indexed: 10/20/2022]
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25
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Contribution of liver mitochondrial membrane-bound glutathione transferase to mitochondrial permeability transition pores. Toxicol Appl Pharmacol 2009; 235:77-85. [DOI: 10.1016/j.taap.2008.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/12/2008] [Accepted: 11/17/2008] [Indexed: 12/20/2022]
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26
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Lenglet S, Antigny F, Vetterli L, Dufour JF, Rossier MF. Hint2 is expressed in the mitochondria of H295R cells and is involved in steroidogenesis. Endocrinology 2008; 149:5461-9. [PMID: 18653718 DOI: 10.1210/en.2008-0400] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hint2 belongs to the superfamily of histidine triad hydrolase enzymes. Recently, it has been shown to influence the mitochondria-dependent apoptosis occurring in hepatocytes, but its mechanism of action is still obscure. Here, we demonstrate that Hint2 is expressed in the mitochondria of H295R cells and in normal adrenals, and that this protein is involved in steroidogenesis. The presence of Hint2 in H295R cells was revealed by RT-PCR and by immunoblot analysis of subcellular fractions. The protein appeared associated with mitochondrial membranes, probably facing the interior of the organelle. Hint2 overexpression in H295R cells had no effect on pregnenolone secretion elicited by angiotensin II or K+, whereas protein silencing with specific small interfering RNA resulted in a marked reduction of the steroidogenic response. The duration of the mitochondrial calcium signal induced by angiotensin II was also reduced upon Hint2 down-regulation with small interfering RNA, but not affected after its overexpression, suggesting that under basal conditions, Hint2 is optimally expressed, and not rate limiting in steroidogenesis. Moreover, Hint2 also appeared involved in Ca2+-independent pathways leading to steroid formation. Indeed, pregnenolone formation in response to either forskolin or a hydroxyl analog of cholesterol was markedly reduced after Hint2 silencing. Calcium-dependent and calcium-independent actions of Hint2 on steroidogenesis could be related to its ability to maintain a favorable mitochondrial potential. In conclusion, these data suggest that, in H295R cells, Hint2 is required for an optimal steroidogenic response, possibly because of a particular signalling function exerted within the mitochondria and that still remains to determine at the molecular level.
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Affiliation(s)
- Sébastien Lenglet
- Service of Endocrinology & Diabetology, University Hospital of Geneva, Geneva, Switzerland
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27
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Lee KK, Shimoji M, Hossain QS, Sunakawa H, Aniya Y. Novel function of glutathione transferase in rat liver mitochondrial membrane: Role for cytochrome c release from mitochondria☆⁎Some of the data were presented at the ISSX (International Society for Study of Xenobiotics) Meeting, Oct.12, 2007, in Sendai, Japan. Toxicol Appl Pharmacol 2008; 232:109-18. [DOI: 10.1016/j.taap.2008.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 04/30/2008] [Accepted: 06/17/2008] [Indexed: 10/21/2022]
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28
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Kmita H. Channels of the Outer Membrane ofSaccharomyces cerevisiaeMitochondria: Cooperation and Regulation. Toxicol Mech Methods 2008; 14:13-7. [DOI: 10.1080/15376520490257365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Tokarska-Schlattner M, Boissan M, Munier A, Borot C, Mailleau C, Speer O, Schlattner U, Lacombe ML. The nucleoside diphosphate kinase D (NM23-H4) binds the inner mitochondrial membrane with high affinity to cardiolipin and couples nucleotide transfer with respiration. J Biol Chem 2008; 283:26198-207. [PMID: 18635542 DOI: 10.1074/jbc.m803132200] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nucleoside diphosphate kinase (NDPK/Nm23), responsible for intracellular di- and triphosphonucleoside homeostasis, plays multiple roles in cellular energetics, signaling, proliferation, differentiation and tumor invasion. The only human NDPK with a mitochondrial targeting sequence is NDPK-D, the NME4 gene product, which is a peripheral protein of mitochondrial membranes. Subfractionation of rat liver and HEK 293 cell mitochondria revealed that NDPK-D is essentially bound to the inner membrane. Surface plasmon resonance analysis of the interaction using recombinant NDPK-D and model liposomes showed that NDPK-D interacts electrostatically with anionic phospholipids, with highest affinity observed for cardiolipin. Mutation of the central arginine (Arg-90) in a surface-exposed basic RRK motif unique to NDPK-D strongly reduced interaction with anionic phospholipids. Due to its symmetrical hexameric structure, NDPK-D was able to cross-link anionic phospholipid-containing liposomes, suggesting that NDPK-D could promote intermembrane contacts. Latency assays with isolated mitochondria and antibody binding to mitoplasts indicated a dual orientation for NDPK-D. In HeLa cells, stable expression of wild type but not of the R90D mutant led to membrane-bound enzyme in vivo. Respiration was significantly stimulated by the NDPK substrate TDP in mitochondria containing wild-type NDPK-D, but not in those expressing the R90D mutant, which is catalytically equally active. This indicates local ADP regeneration in the mitochondrial intermembrane space and a tight functional coupling of NDPK-D with oxidative phosphorylation that depends on its membrane-bound state.
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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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31
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Vernoux N, Maniti O, Besson F, Granjon T, Marcillat O, Vial C. Mitochondrial creatine kinase adsorption to biomimetic membranes: a Langmuir monolayer study. J Colloid Interface Sci 2007; 310:436-45. [PMID: 17359991 DOI: 10.1016/j.jcis.2007.01.093] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 01/29/2007] [Accepted: 01/29/2007] [Indexed: 11/16/2022]
Abstract
Interaction of mitochondrial creatine kinase (mtCK) with either synthetic or natural zwitterionic or acidic phospholipids was monitored by surface pressure measurements. Injection of mtCK beneath a monolayer at very low surface pressure results in a large increase in the apparent area per lipid molecule reflecting the intrinsic surface activity of the protein. This effect is particularly pronounced with anionic phospholipid-containing films. Upon compression to high lateral pressure, the protein is squeezed out of the lipid monolayer. On the contrary, mtCK injected beneath a monolayer compressed at 30 mN/m, does not insert into the monolayer but is concentrated below the surface by anionic phospholipids as evidenced by the immediate and strong increase in the apparent molecular area occurring upon decompression. Below 8 mN/m the protein adsorbs to the interface and remains intercalated until the lateral pressure increases again. The critical pressure of insertion is higher for anionic lipid-containing monolayers than for films containing only zwitterionic phospholipids. In the former case it is markedly diminished by NaCl. The adsorption of mtCK depends on the percentage of negative charges carried by the monolayer and is reduced by increasing NaCl concentrations. However, the residual interaction existing in the absence of a global negative charge on the membrane may indicate that this interaction also involves a hydrophobic component.
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Affiliation(s)
- Nathalie Vernoux
- CNRS UMR 5246/IMBL, Biomembranes et enzymes associés, Université Lyon 1, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne cedex, France
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32
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Armstrong JS. The role of the mitochondrial permeability transition in cell death. Mitochondrion 2006; 6:225-34. [PMID: 16935572 DOI: 10.1016/j.mito.2006.07.006] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 07/23/2006] [Accepted: 07/25/2006] [Indexed: 01/06/2023]
Abstract
The mitochondrial permeability transition (MPT) is a non-selective inner membrane permeabilization that occurs in response to increased calcium load and redox stress. Currently, two models of the MPT exist including the, largely hypothetical, native proteinaceous pore model and the oxidized inner membrane protein model which may reflect the extremes in a continuum of changes that occur to the inner membrane prior to its permeabilization. Here I discuss evidence that the MPT per se leads to necrosis, but not cytochrome c release and apoptosis. However, data also suggest that signaling crosstalk between the MPT and Bcl-2 family proteins occurs indicating an important role for the MPT in apoptosis.
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Affiliation(s)
- Jeffrey S Armstrong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore.
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Abstract
The permeability transition pore (PTP) is a multi-protein complex at contact sites of the inner with the outer mitochondrial membrane. Research over the past years has led to the concept that the PTP occupies a central role in cell death induction. Numerous apoptosis signals convert this protein aggregate into an unspecific pore, thus activating mitochondria for the cellular self-destruction process. Here, we describe the evidence for this and the various approaches being undertaken to elucidate its subunit composition and mode of regulation. In particular, we review data that indicate a role of specific PTP subunits for apoptosis inhibition during tumorigenesis.
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Affiliation(s)
- C Brenner
- University of Versailles/St Quentin, CNRS UMR 8159, Versailles, France.
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34
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Affiliation(s)
- J E Wilson
- Department of Biochemistry, Michigan State University, East Lansing 48824
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35
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Vernoux N, Granjon T, Marcillat O, Besson F, Vial C. Interfacial behavior of cytoplasmic and mitochondrial creatine kinase oligomeric states. Biopolymers 2006; 81:270-81. [PMID: 16283667 DOI: 10.1002/bip.20412] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Adsorption to the air/water interface of isoenzymes of creatine kinase was investigated using surface pressure-area isotherms and Brewster angle microscopy (BAM) observations. Octameric mitochondrial creatine kinase (mtCK) exhibits a significant affinity for the air/water interface. Whatever the mode of formation of the interfacial film, i.e., injection of the protein in the subphase or spreading onto the buffer surface, the final arrangement and conformation adopted by mtCK molecules lead to a similar result. In contrast, the dimeric isoenzymes mtCK and cytosolic MMCK do not induce any surface pressure variation. However, when the subphase contains 0.3M NaCl, both isoenzymes adsorb to the interface. When treated with 0.8 or 3M GdnHCl, muscle creatine kinase (MMCK) becomes surface active and occupies a greater surface than mtCK. This result contrasts with previous observations, often derived from monomeric proteins, that their surface activity is increased upon unfolding. It underlines the possible influence exerted by the protein oligomeric state on its interfacial activity. At a subphase pH of 8.8, which corresponds to the pI of octameric mtCK, the profiles of the isotherms obtained with dimeric and octameric states and the resistance to compression of the protein monolayers are significantly affected when compared to those recorded at pH 7.4. These data suggest that the octamer is more hydrophobic than the dimer and may contribute to explaining why octamers bind to the inner mitochondrial membrane while dimers do not.
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Affiliation(s)
- Nathalie Vernoux
- UMR CNRS 5013, Biomembranes et enzymes associés, Université Claude Bernard Lyon I, 43, boulevard du 11 Novembre 1918, 69622 Villeurbanne cedex, France
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36
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Lipskaya TY, Voinova VV. Functional coupling between nucleoside diphosphate kinase of the outer mitochondrial compartment and oxidative phosphorylation. BIOCHEMISTRY (MOSCOW) 2006; 70:1354-62. [PMID: 16417458 DOI: 10.1007/s10541-005-0269-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In rat liver mitochondria all nucleoside diphosphate kinase of the outer compartment is associated with the outer surface of the outer membrane (Lipskaya, T. Yu., and Plakida, K. N. (2003) Biochemistry (Moscow), 68, 1136-1144). In the present study, three systems operating as ADP donors for oxidative phosphorylation have been investigated. The outer membrane bound nucleoside diphosphate kinase was the first system tested. Two others employed yeast hexokinase and yeast nucleoside diphosphate kinase. The two enzymes exhibited the same activity but could not bind to mitochondrial membranes. In all three systems, muscle creatine phosphokinase was the external agent competing with the oxidative phosphorylation system for ADP. Determination of mitochondrial respiration rate in the presence of increasing quantities of creatine phosphokinase revealed that at large excess of creatine phosphokinase activity over other kinase activities (of the three systems tested) and oxidative phosphorylation the creatine phosphokinase reaction reached a quasi-equilibrium state. Under these conditions equilibrium concentrations of all creatine phosphokinase substrates were determined and K(eq)app of this reaction was calculated for the system with yeast hexokinase. In samples containing active mitochondrial nucleoside diphosphate kinase the concentrations of ATP, creatine, and phosphocreatine were determined and the quasi-equilibrium concentration of ADP was calculated using the K(eq)app value. At balance of quasi-equilibrium concentrations of ADP and ATP/ADP ratio the mitochondrial respiration rate in the system containing nucleoside diphosphate kinase was 21% of the respiration rate assayed in the absence of creatine phosphokinase; in the system containing yeast hexokinase this parameter was only 7% of the respiration rate assayed in the absence of creatine phosphokinase. Substitution of mitochondrial nucleoside diphosphate kinase with yeast nucleoside diphosphate kinase abolished this difference. It is concluded that oxidative phosphorylation is accompanied by appearance of functional coupling between mitochondrial nucleoside diphosphate kinase and the oxidative phosphorylation system. Possible mechanisms of this coupling are discussed.
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Affiliation(s)
- T Yu Lipskaya
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
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Mannella CA. The relevance of mitochondrial membrane topology to mitochondrial function. Biochim Biophys Acta Mol Basis Dis 2006; 1762:140-7. [PMID: 16054341 DOI: 10.1016/j.bbadis.2005.07.001] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/20/2005] [Accepted: 07/04/2005] [Indexed: 11/29/2022]
Abstract
This review summarizes recent findings from electron tomography about the three-dimensional shape of mitochondrial membranes and its possible influence on a range of mitochondrial functions. The inner membrane invaginations called cristae are pleomorphic, typically connected by narrow tubular junctions of variable length to the inner boundary membrane. This design may restrict intra-mitochondrial diffusion of metabolites such as ADP, and of soluble proteins such as cytochrome c. Tomographic images of a variety of mitochondria suggest that inner membrane topology reflects a balance between membrane fusion and fission. Proteins that can affect cristae morphology include tBid, which triggers cytochrome c release in apoptosis, and the dynamin-like protein Mgm1, involved in inter-mitochondrial membrane fusion. In frozen-hydrated rat-liver mitochondria, the space between the inner and outer membranes contains 10-15 nm particles that may represent macromolecular complexes involved in activities that span the two membranes.
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Affiliation(s)
- Carmen A Mannella
- Resource for Visualization of Biological Complexity, Wadsworth Center, Empire State Plaza, Albany, NY 12201-0509, USA.
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Bannikova S, Zorov DB, Shoeman RL, Tolstonog GV, Traub P. Stability and Association with the Cytomatrix of Mitochondrial DNA in Spontaneously Immortalized Mouse Embryo Fibroblasts Containing or Lacking the Intermediate Filament Protein Vimentin. DNA Cell Biol 2005; 24:710-35. [PMID: 16274293 DOI: 10.1089/dna.2005.24.710] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To extend previous observations demonstrating differences in number, morphology, and activity of mitochondria in spontaneously immortalized vim(+) and vim(-) fibroblasts derived from wild-type and vimentin knockout mice, some structural and functional aspects of mitochondrial genome performance and integrity in both types of cells were investigated. Primary Vim(+/+) and Vim(-/-) fibroblasts, which escaped terminal differentiation by immortalization were characterized by an almost twofold lower mtDNA content in comparison to that of their primary precursor cells, whereby the average mtDNA copy number in two clones of vim(+) cells was lower by a factor of 0.6 than that in four clones of vim(-) cells. However, during serial subcultivation up to high passage numbers, the vim(+) and vim() fibroblasts increased their mtDNA copy number 1.5- and 2.5-fold, respectively. While early-passage cells of the vim(+) and vim(-) fibroblast clones differed only slightly in the ratio between mtDNA content and mitochondrial mass represented by mtHSP70 protein, after ca. 300 population doublings the average mtDNA/mtmass ratio in the vim(+) and vim() cells was increased by a factor of 2 and 4.5, respectively. During subcultivation, both types of cells acquired the fully transformed phenotype. These findings suggest that cytoskeletal vimentin filaments exert a strong influence on the mechanisms controlling mtDNA copy number during serial subcultivation of immortalized mouse embryo fibroblasts, and that vimentin deficiency causes a disproportionately enhanced mtDNA content in high-passage vim(-) fibroblasts. Such a role of vimentin filaments was supported by the stronger retention potential for mtDNA and mtDNA polymerase (gamma) detected in vim(+) fibroblasts by Triton X-100 extraction of mitochondria and agaroseembedded cells. Moreover, although the vim(+) and vim(-) fibroblasts were equally active in generating free radicals, the vim(-) cells exhibited higher levels of immunologically detectable 8-oxoG and mismatch repair proteins MSH2 and MLH1 in their mitochondria. Because in vim(-) fibroblasts only one point mutation was detected in the mtDNA D-loop control region, these cells are apparently able to efficiently remove oxidatively damaged nucleobases. On the other hand, a number of large-scale mtDNA deletions were found in high-passage vim(-) fibroblasts, but not in low-passage vim(-) cells and vim(+) cells of both low and high passage. Large mtDNA deletions were also induced in young vim(-) fibroblasts by treatment with the DNA intercalator ethidium bromide, whereas no such deletions were found after treatment of vim(+) cells. These results indicate that in immortalized vim(-) fibroblasts the mitochondrial genome is prone to large-scale rearrangements, probably due to insufficient control of mtDNA repair and recombination processes in the absence of vimentin.
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Kmita H, Antos N, Wojtkowska M, Hryniewiecka L. Processes underlying the upregulation of Tom proteins in S. cerevisiae mitochondria depleted of the VDAC channel. J Bioenerg Biomembr 2004; 36:187-93. [PMID: 15224968 DOI: 10.1023/b:jobb.0000023622.66554.a6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been shown recently that in Saccharomyces cerevisiae mitochondria depleted of the VDAC channel (delta por1 mitochondria), the TOM complex channel substitutes for the VDAC channel. The additional function of the TOM complex channel is probably facilitated by the upregulation of nuclear-encoded components of the TOM complex as has been shown for Tom40 (a major component of the channel) and Tom70 (one of the surface receptors). Here we report that in S. cerevisiae cells the VDAC channel seems to be an important signal in the expression of the TOM complex components. S. cerevisiae cells depleted of the VDAC channel (delta por1 cells) contain distinctly increased levels of Tom40mRNA, and Tom70mRNA, but their synthesis and translation are affected differentially by the applied inhibitors of transcription and translation. Consequently, it may be concluded that depletion of the VDAC channel might influence differentially the expression of TOM40 and TOM70 genes.
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Affiliation(s)
- Hanna Kmita
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Fredry 10, 61-701 Poznan, Poland.
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40
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Gellerich FN, Trumbeckaite S, Müller T, Deschauer M, Chen Y, Gizatullina Z, Zierz S. Energetic depression caused by mitochondrial dysfunction. Mol Cell Biochem 2004; 256-257:391-405. [PMID: 14977198 DOI: 10.1023/b:mcbi.0000009885.34498.e6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mitochondria, providing most of ATP needed for cell work, realizing numerous specific functions as biosyntheses or degradations, contributing to Ca2+ signalling also play a key role in the pathways to cell death. Impairment of mitochondrial functions caused by mutations of mt-genome and by acute processes are responsible for numerous diseases. The relations between changes on the level of molecules and the clinical state are rather complex, and the prediction of thresholds is difficult. Therefore investigations on different levels of an organismus (genome, metabolites, enzymes, mitochondrial function in vivo and in vitro) are necessary (multi level approach). Metabolic control theory is a valuable tool for understanding the different effects of mutations on the level of enzyme activities and mitochondrial function. Decreased concentrations of adenine nucleotides, leaky outer and inner mitochondrial membranes, decreased rates of mitochondrial linked pathways and decreased activities of respiratory chain enzymes contribute to depression of cellular energy metabolism characterized by decreased cytosolic phosphorylation potentials as one of the most important consequences of mitochondrial impairments. This review regards classical bioenergetic mechanisms of mitochondrial impairment which contribute to energetic depression.
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Affiliation(s)
- Frank Norbert Gellerich
- Muskellabor der Neurologischen Klinik, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany.
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Abstract
Mitochondria are essential organelles that are involved in numerous metabolic pathways and produce the major part of intracellular ATP by oxidative phosphorylation. Their ultrastructure was solved in the 1950s by electron microscopic analysis of ultrathin sections. Based on these pioneering studies and on the endosymbiotic origin of mitochondria, cells are often assumed to contain numerous independent mitochondria with a size similar to that of bacteria. However, electron microscopy of thick sections reveals that mitochondria form elongated and branched filaments. Optical microscopy of living cells demonstrates that mitochondrial filaments continuously modify their position and morphology and that they undergo frequent fission and fusion reactions. In this review, we revise the actual knowledge on the ultrastructure, the organization and the dynamics of the mitochondrial compartment. We review recent findings showing that mitochondria exchange molecules by fusion and we present the main proteins involved in mitochondrial fusion and fission reactions. Finally, we discuss the functional and physiological relevance of mitochondrial dynamics.
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Affiliation(s)
- F Malka
- INSERM U582 (IFR 14 UPMC)-Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, 47, boulevard de l'Hôpital, 75651 Paris, France
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Shi Y, Chen J, Weng C, Chen R, Zheng Y, Chen Q, Tang H. Identification of the protein-protein contact site and interaction mode of human VDAC1 with Bcl-2 family proteins. Biochem Biophys Res Commun 2003; 305:989-96. [PMID: 12767928 DOI: 10.1016/s0006-291x(03)00871-4] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Bcl-2 family of proteins plays differential roles in regulation of mitochondria-mediated apoptosis, by either promoting or inhibiting the release of apoptogenic molecules from mitochondria to cytosol. Bcl-2 family proteins modulate the mitochondrial permeability through interaction with adenine nucleotide translocator (ANT), voltage-dependent anion channel (VDAC), ADP/ATP exchange, or oxidative phosphorylation during apoptosis. Although the mitochondrial homeostasis is affected by the relative ratio of pro- and anti-apoptotic Bcl-2 family members, the molecular mechanism underlying the release of mitochondrial intermembrane proteins remains elusive. Here we reported the biochemical evidence that both pro-apoptotic Bax and anti-apoptotic Bcl-X(L) might simultaneously contact the putative loop regions of human VDAC1, and the existence of VDAC1-Bax-Bcl-X(L) tertiary complex in vitro suggested that VDAC1 channel conformation and mitochondrial permeability could be determined by the delicate balance between Bax and Bcl-X(L).
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Affiliation(s)
- Yong Shi
- The Center for Molecular Microbiology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
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Uribe A, Strauss JF, Martínez F. Contact sites from human placental mitochondria: characterization and role in progesterone synthesis. Arch Biochem Biophys 2003; 413:172-81. [PMID: 12729614 DOI: 10.1016/s0003-9861(03)00097-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To understand the functional compartmentalization of human placental mitochondria, we analyzed the composition and steroidogenic activity of contact sites. Several fractions containing contact sites were isolated using osmotic shock treatment and sucrose gradient centrifugation. These fractions contained various proteins and marker enzymes associated with mitochondrial membranes. The fractions containing the cytochrome P450 side chain cleavage system, cholesterol, nicotinamide adenine dinucleotide phosphate-isocitrate dehydrogenase, porin, and adenosine 5(')-triphosphate-diphosphohydrolase activity showed the capacity to synthesize progesterone. Our observations indicate that all necessary elements and enzymes for steroidogenesis are present and functional in placental mitochondrial contact sites. This organization may facilitate the metabolism of cholesterol delivered to the outer mitochondrial membrane into steroid hormones by the inner mitochondrial membrane cholesterol side chain cleavage system.
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Affiliation(s)
- Aida Uribe
- Departamento de Bioquimica, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-159, 04510 Mexico, DF, Mexico
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Shi Y, Jiang C, Chen Q, Tang H. One-step on-column affinity refolding purification and functional analysis of recombinant human VDAC1. Biochem Biophys Res Commun 2003; 303:475-82. [PMID: 12659842 DOI: 10.1016/s0006-291x(03)00359-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The outer mitochondrial membrane porin, voltage-dependent anion-selective channel (VDAC), is believed to play an important role in mediating mitochondria-dependent apoptosis. However, detailed structure-function studies of VDAC have been hindered by the difficulties to obtain a soluble, correctly folded, and fully active form of the recombinant VDAC and its mutant variants due to its transmembrane nature. Here we report a high-throughput one-step chromatographic procedure in purification of recombinant human VDAC1 (rhVDAC1) protein overexpressed in bacteria. The improved methodology could generate a large quantity of rhVDAC1 with correct folding in terms of the secondary structure, with full biological activities in mediating cytochrome c release and in interaction with Bcl-X(L). The method will significantly benefit genetic, biochemical, and structural studies of this critical channel protein.
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Affiliation(s)
- Yong Shi
- The Center for Molecular Microbiology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
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Broadway NM, Pease RJ, Birdsey G, Shayeghi M, Turner NA, David Saggerson E. The liver isoform of carnitine palmitoyltransferase 1 is not targeted to the endoplasmic reticulum. Biochem J 2003; 370:223-31. [PMID: 12401113 PMCID: PMC1223134 DOI: 10.1042/bj20021269] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2002] [Accepted: 10/25/2002] [Indexed: 11/17/2022]
Abstract
Liver microsomal fractions contain a malonyl-CoA-inhibitable carnitine acyltransferase (CAT) activity. It has been proposed [Fraser, Corstorphine, Price and Zammit (1999) FEBS Lett. 446, 69-74] that this microsomal CAT activity is due to the liver form of carnitine palmitoyltransferase 1 (L-CPT1) being targeted to the endoplasmic reticulum (ER) membrane as well as to mitochondria, possibly by an N-terminal signal sequence [Cohen, Guillerault, Girard and Prip-Buus (2001) J. Biol. Chem. 276, 5403-5411]. COS-1 cells were transiently transfected to express a fusion protein in which enhanced green fluorescent protein was fused to the C-terminus of L-CPT1. Confocal microscopy showed that this fusion protein was localized to mitochondria, and possibly to peroxisomes, but not to the ER. cDNAs corresponding to truncated (amino acids 1-328) or full-length L-CPT1 were transcribed and translated in the presence of canine pancreatic microsomes. However, there was no evidence of authentic insertion of CPT1 into the ER membrane. Rat liver microsomal fractions purified by sucrose-density-gradient centrifugation contained an 88 kDa protein (p88) which was recognized by an anti-L-CPT1 antibody and by 2,4-dinitrophenol-etomoxiryl-CoA, a covalent inhibitor of L-CPT1. Abundance of p88 and malonyl-CoA-inhibitable CAT activity were increased approx. 3-fold by starvation for 24 h. Deoxycholate solubilized p88 and malonyl-CoA-inhibitable CAT activity from microsomes to approximately the same extent. The microsomal fraction contained porin, which, relative to total protein, was as abundant as in crude mitochondrial outer membranes fractions. It is concluded that L-CPT1 is not targeted to the ER membrane and that malonyl-CoA CAT in microsomal fractions is L-CPT1 that is derived from mitochondria, possibly from membrane contact sites.
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Affiliation(s)
- Neil M Broadway
- Department of Biochemistry and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
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Priault M, Bessoule JJ, Grelaud-Coq A, Camougrand N, Manon S. Bax-induced cell death in yeast depends on mitochondrial lipid oxidation. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:5440-50. [PMID: 12423342 DOI: 10.1046/j.1432-1033.2002.03234.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The oxidant function of pro-apoptotic protein Bax was investigated through heterologous expression in yeast. Direct measurements of fatty acid content show that Bax-expression induces oxidation of mitochondrial lipids. This effect is prevented by the coexpression of Bcl-xL. The oxidation actually could be followed on isolated mitochondria as respiration-induced peroxidation of polyunsaturated cis-parinaric acid and on whole cells as the increase in the amount of thiobarbituric acid-reactive products. Treatments that increase the unsaturation ratio of lipids, making them more sensitive to oxidation, increase kinetics of Bax-induced death. Conversely, inhibitors of lipid oxidation and treatments that decrease the unsaturation ratio of fatty acids decrease kinetics of Bax-induced death. Taken together, these results show that Bax-induced mitochondrial lipid oxidation is relevant to Bax-induced cell death. Conversely, lipid oxidation is poorly related to the massive Bax-induced superoxide and hydrogen peroxide accumulation, which occurs at the same time, as chemical or enzymatic scavenging of ROS does not prevent lipid oxidation nor has any effects on kinetics of Bax-induced cell death. Whatever the origin of mitochondrial lipid oxidation, these data show that it represents a major step in the cascade of events leading to Bax-induced cell death. These results are discussed in the light of the role of lipid oxidation both in mammalian apoptosis and in other forms of cell death in other organisms.
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Affiliation(s)
- Muriel Priault
- UMR5095 C.N.R.S./Université de Bordeaux 2, Bordeaux, France; UMR5544 C.N.R.S./Université de Bordeaux 2, Bordeaux, France
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Ziegelhöffer-Mihalovicová B, Ziegelhöffer A, Ravingerová T, Kolár F, Jacob W, Tribulová N. Regulation of mitochondrial contact sites in neonatal, juvenile and diabetic hearts. Mol Cell Biochem 2002; 236:37-44. [PMID: 12190119 DOI: 10.1023/a:1016189808285] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondrial contact sites (MiCS) are dynamic structures involved in high capacity transport of energy from mitochondria into the cytosole. Previous studies revealed that in normal conditions the actual number of MiCS is in correlation with the energy requirements of the heart, particularly with those for its contractile work. Although the detailed mechanisms of signalling between the processes of energy utilisation and MiCS formation in the heart are not yet elucidated, it is known that intracellular Ca2+ transients are intimately involved in this crosstalk. The present study is devoted to investigation of Ca2+-linked MiCS formation in healthy adult hearts and in hearts with modified Ca2+-handling such as in developing, in juvenile and diabetic myocardium. Experiments were performed on hearts of healthy rats on the 22nd embryonal day, 1st, 4th, 7th and 14th postnatal days as well as on adult hearts. Diabetic hearts were investigated on the 8th day after streptozotocin injection (45 mg x kg(-1) iv.) to adult rats. Intracellular Ca2+ movements were affected by modulation of Ca2+ concentration in perfusion solution (1.6 or 2.2 mmol l(-1) in isolated, Langendorff-perfused hearts, by calcium paradox (CaP) or by replacing of Ca2+ by Cd2+ ions. Elevation of extracellular Ca2+ was reflected by 30.1, 10.4 and 24.1% increase in intracellular free Ca2+ concentration in healthy adult, diabetic and 14-day old hearts respectively. In developing hearts the amount of MiCS was culminating on the 4th postnatal day. In adult hearts, elevated calcium in the perfusion solution, CaP as well as diabetes led to a significant increase in the amounts of MiCS formed (58.1, 77.2 and 86.5% respectively; p < 0.05). Diabetic and 14-day old hearts naturally exhibited amounts of MiCS comparable to those obtained by Ca2+-stimulation of MiCS formation in adult healthy hearts. In contrast to healthy controls, perfusion of diabetic and 14-day old hearts with elevated Ca2+ as well as induction of CaP exerted little influence on MiCS formation (4.4 and 8.2% for elevated Ca2+; 2.9 and 10.7% for CaP; p > 0.05). A replacement of Ca2+ by Cd2+ ions lowered the amount of MiCS in healthy adult and diabetic hearts (61 and 52.2%; p < 0.05). In conclusion, during development, the formation of MiCS may be influenced by both, permanent stimulation by Ca2+-signalling and the availability of mCPK. In healthy adult hearts the amount of MiCS is modulated by intracellular Ca2+ transients in response to changes in extracellular Ca2+ concentration. In diabetic hearts the modulation of MiCS formation is naturally attenuated, apparently as a consequence of persisting alterations in Ca2+-handling.
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Colquhoun A. Gamma-linolenic acid alters the composition of mitochondrial membrane subfractions, decreases outer mitochondrial membrane binding of hexokinase and alters carnitine palmitoyltransferase I properties in the Walker 256 rat tumour. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1583:74-84. [PMID: 12069851 DOI: 10.1016/s1388-1981(02)00162-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gamma-linolenic acid (GLA) is known to be an inhibitor of Walker 256 tumour growth in vivo and causes changes in both mitochondrial structure and cellular metabolism. The aim of the present study was to investigate in greater detail the changes in energy metabolism and ultrastructure induced by GLA in this tumour model. A diet containing 5.5% GLA, which is sufficient to cause a 45% decrease in tumour growth, was found to almost double the triacylglycerol (TAG) content of the tumour and to increase the quantity of 20:3 n-6, 20:4 n-6, 22:4 n-6 and 22:5 n-6 in the TAG fraction as determined by gas chromatography-mass spectrometry (GCMS) analysis. Morphometric analysis of the tumour by electron microscopy confirmed this increase in TAG content, identifying a doubling of lipid droplet content in the GLA dietary group. The surface density of mitochondrial cristae was reduced, along with a reduction in the number of contact sites (CS) and matrix granules. These three parameters are likely indicators of a reduction in mitochondrial metabolic activity. Measurement of hexokinase activity identified that much of the total hexokinase activity was in the mitochondrially bound form (66.5%) in the control tumour and that GLA caused a decrease in the amount of enzyme in the bound form (39.3%). The fatty acyl chain composition of the tumour mitochondrial subfractions, outer membranes (OM), CSs and inner membranes (IM) was determined by GCMS. All subfractions showed considerable increases in 20:3 n-6 and decreases in 18:1 n-9, 18:2 n-6 and 22:6 n-3, when exposed to GLA diet. These changes were reflected in a large increase in the n-6/n-3 ratio in the GLA OM vs. the control OM, 21.299 vs. 6.747, respectively. The maximal activity of OM carnitine palmitoyltransferase I (CPT I) was found to be decreased by 61.6% in the GLA diet group. This was accompanied by a decrease in malonyl CoA sensitivity and a decrease in affinity for 16:0 CoA substrate. Such changes in CPT I may be the cause of cytoplasmic acyl CoA accumulation seen in this tumour model. These effects, together with previously reported increases in lipid peroxidation, lead to the conclusion that GLA may cause inhibition of tumour cell growth through separate but interlinked pathways, all of which eventually lead to apoptosis and a decrease in tumour development. The influence of mitochondrial OM fatty acyl chain composition upon two important enzymes of energy metabolism, hexokinase and CPT I, both of which have been linked to apoptosis, is of considerable importance for future studies on fatty acid-induced cell death.
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Affiliation(s)
- Alison Colquhoun
- Departamento de Histologia e Embriologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, CEP 05508-900, Brazil.
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49
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Abstract
Eukaryotic porins are a group of membrane proteins whose best known role is to form an aqueous pore channel in the mitochondrial outer membrane. As opposed to the bacterial porins (a large family of protein whose 3D structure has been determined by X-ray diffraction), the structure of eukaryotic porins (also termed VDACs, voltage-dependent anion-selective channels) is still a matter of debate. We analysed the secondary structure of VDAC from the yeast Saccharomyces cerevisiae, the fungus Neurospora crassa and the mouse with different types of neural network-based predictors. The predictors were able to discriminate membrane beta-strands, globular alpha-helices and membrane alpha-helices and localised, in all three VDAC sequences, 16 beta-strands along the chain. For all three sequences the N-terminal region showed a high propensity to form a globular alpha-helix. The 16 beta-strand VDAC motif was thus aligned to a bacterial porin-derived template containing a similar 16 beta-strand motif. The alignment of the VDAC sequence with the bacterial porin sequence was used to compute a set of 3D coordinates, which constitutes the first 3D prediction of a eukaryotic porin. All the predicted structures assume a beta-barrel structure composed of 16 beta-strands with the N-terminus outside the membrane. Loops are shorter in this side of the membrane than in the other, where two long loops are protruding. The shape of the pore varies between almost circular for Neurospora and mouse and slightly oval for yeast. Average values between 3 and 2.5 nm at the C-carbon backbone are found for the diameter of the channels. In this model VDAC shows large portions of the structure exposed on both sides of the membrane. The architecture we determine allows speculation about the mechanism of possible interactions between VDAC and other proteins on both sides of the mitochondrial outer membrane. The computed 3D model is consistent with most of the experimental results so far reported.
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Affiliation(s)
- Rita Casadio
- Laboratory of Biocomputing, Centro Interdipartimentale per le Ricerche Biotecnologiche, Bologna, Italy
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50
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Gellerich FN, Laterveer FD, Zierz S, Nicolay K. The quantitation of ADP diffusion gradients across the outer membrane of heart mitochondria in the presence of macromolecules. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1554:48-56. [PMID: 12034470 DOI: 10.1016/s0005-2728(02)00212-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We have previously provided evidence that diffusion of metabolites across the porin pores of mitochondrial outer membrane is hindered. A functional consequence of this diffusion limitation is the dynamic compartmentation of ADP in the intermembrane space. These earlier studies were done on isolated mitochondria suspended in isotonic media without macromolecules, in which intermembrane space of mitochondria is enlarged. The present study was undertaken to assess the diffusion limitation of outer membrane in the presence of 10% (w/v) dextran M20, in order to mimic the action of cytosolic macromolecules on mitochondria. Under these conditions, mitochondria have a more native, condensed configuration.Flux-dependent concentration gradients of ADP were estimated by measuring the ADP diffusion fluxes across the porin pores of isolated rat heart mitochondria incubated together with pyruvate kinase (PK), both of which compete for ADP regenerated by mitochondrial creatine kinase (mtCK) within the intermembrane space or by yeast hexokinase (HK) extramitochondrially. From diffusion fluxes and bulk phase concentrations of ADP, its concentrations in the intermembrane space were calculated using Fick's law of diffusion. Flux-dependent gradients up to 23 microM ADP (for a diffusion rate of J(Dif)=1.9 micromol ADP/min/mg mitochondrial protein) were observed. These gradients are about twice those estimated in the absence of dextran and in the same order of magnitude as the cytosolic ADP concentration (30 microM), but they are negligibly low for cytosolic ATP (5 mM). Therefore, it is concluded that the dynamic ADP compartmentation is of biological importance for intact heart cells. If mtCK generates ADP within the intermembrane space, the local ADP concentration can be clearly higher than in the cytosol resulting in higher extramitochondrial phosphorylation potentials. In this way, mtCK contributes to ensure optimal kinetic conditions for ATP-splitting reactions in the extramitochondrial compartment.
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Affiliation(s)
- Frank Norbert Gellerich
- Muskellabor der Neurologischen Klinik und Poliklinik, Martin-Luther-Universität, Halle-Wittenberg, Julius-Kühn-Str. 7, D-06097 Halle/Saale, Halle-Wittenberg, Germany.
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