251
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Arnould T, Michel S, Renard P. Mitochondria Retrograde Signaling and the UPR mt: Where Are We in Mammals? Int J Mol Sci 2015; 16:18224-51. [PMID: 26258774 PMCID: PMC4581242 DOI: 10.3390/ijms160818224] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 06/26/2015] [Accepted: 07/24/2015] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial unfolded protein response is a form of retrograde signaling that contributes to ensuring the maintenance of quality control of mitochondria, allowing functional integrity of the mitochondrial proteome. When misfolded proteins or unassembled complexes accumulate beyond the folding capacity, it leads to alteration of proteostasis, damages, and organelle/cell dysfunction. Extensively studied for the ER, it was recently reported that this kind of signaling for mitochondrion would also be able to communicate with the nucleus in response to impaired proteostasis. The mitochondrial unfolded protein response (UPRmt) is activated in response to different types and levels of stress, especially in conditions where unfolded or misfolded mitochondrial proteins accumulate and aggregate. A specific UPRmt could thus be initiated to boost folding and degradation capacity in response to unfolded and aggregated protein accumulation. Although first described in mammals, the UPRmt was mainly studied in Caenorhabditis elegans, and accumulating evidence suggests that mechanisms triggered in response to a UPRmt might be different in C. elegans and mammals. In this review, we discuss and integrate recent data from the literature to address whether the UPRmt is relevant to mitochondrial homeostasis in mammals and to analyze the putative role of integrated stress response (ISR) activation in response to the inhibition of mtDNA expression and/or accumulation of mitochondrial mis/unfolded proteins.
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Affiliation(s)
- Thierry Arnould
- Laboratory of Biochemistry and Cell Biology (URBC), Namur Research Institute for Life Sciences (NARILIS), University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
| | - Sébastien Michel
- Laboratory of Biochemistry and Cell Biology (URBC), Namur Research Institute for Life Sciences (NARILIS), University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
- Department of Physiology, University of Lausanne, Rue du Bugnon 7, CH-1005 Lausanne, Switzerland.
| | - Patricia Renard
- Laboratory of Biochemistry and Cell Biology (URBC), Namur Research Institute for Life Sciences (NARILIS), University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
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252
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Hood DA, Tryon LD, Vainshtein A, Memme J, Chen C, Pauly M, Crilly MJ, Carter H. Exercise and the Regulation of Mitochondrial Turnover. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 135:99-127. [PMID: 26477912 DOI: 10.1016/bs.pmbts.2015.07.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Exercise is a well-known stimulus for the expansion of the mitochondrial pool within skeletal muscle. Mitochondria have a remarkable ability to remodel their networks and can respond to an array of signaling stimuli following contractile activity to adapt to the metabolic demands of the tissue, synthesizing proteins to expand the mitochondrial reticulum. In addition, when they become dysfunctional, these organelles can be recycled by a specialized intracellular system. The signals regulating this mitochondrial life cycle of synthesis and degradation during exercise are still an area of great research interest. As mitochondrial turnover has valuable consequences in physical performance, in addition to metabolic health, disease, and aging, consideration of the signals which control this cycle is vital. This review focuses on the regulation of mitochondrial turnover in skeletal muscle and summarizes our current understanding of the impact that exercise has in modulating this process.
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Affiliation(s)
- David A Hood
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
| | - Liam D Tryon
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Anna Vainshtein
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Jonathan Memme
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Chris Chen
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Marion Pauly
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Matthew J Crilly
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Heather Carter
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
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253
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Abstract
Mitochondria are highly dynamic, except in adult cardiomyocytes. Yet, the fission and fusion-promoting proteins that mediate mitochondrial dynamism are highly expressed in, and essential to the normal functioning of, hearts. Here, we review accumulating evidence supporting important roles for mitochondrial fission and fusion in cardiac mitochondrial quality control, focusing on the PTEN-induced putative kinase 1-Parkin mitophagy pathway. Based in part on recent findings from in vivo mouse models in which mitofusin-mediated mitochondrial fusion or dynamin-related protein 1-mediated mitochondrial fission was conditionally interrupted in cardiac myocytes, we propose several new concepts that may provide insight into the cardiac mitochondrial dynamism-mitophagy interactome.
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Affiliation(s)
- Orian S Shirihai
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.)
| | - Moshi Song
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.)
| | - Gerald W Dorn
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.).
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254
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Bohnert M, Pfanner N, van der Laan M. Mitochondrial machineries for insertion of membrane proteins. Curr Opin Struct Biol 2015; 33:92-102. [DOI: 10.1016/j.sbi.2015.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/13/2015] [Accepted: 07/27/2015] [Indexed: 01/08/2023]
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255
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Mitochondrial oxidative stress promotes atrial fibrillation. Sci Rep 2015; 5:11427. [PMID: 26169582 PMCID: PMC4501003 DOI: 10.1038/srep11427] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/26/2015] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress has been suggested to play a role in the pathogenesis of atrial fibrillation (AF). Indeed, the prevalence of AF increases with age as does oxidative stress. However, the mechanisms linking redox state to AF are not well understood. In this study we identify a link between oxidative stress and aberrant intracellular Ca2+ release via the type 2 ryanodine receptor (RyR2) that promotes AF. We show that RyR2 are oxidized in the atria of patients with chronic AF compared with individuals in sinus rhythm. To dissect the molecular mechanism linking RyR2 oxidation to AF we used two murine models harboring RyR2 mutations that cause intracellular Ca2+ leak. Mice with intracellular Ca2+ leak exhibited increased atrial RyR2 oxidation, mitochondrial dysfunction, reactive oxygen species (ROS) production and AF susceptibility. Both genetic inhibition of mitochondrial ROS production and pharmacological treatment of RyR2 leakage prevented AF. Collectively, our results indicate that alterations of RyR2 and mitochondrial ROS generation form a vicious cycle in the development of AF. Targeting this previously unrecognized mechanism could be useful in developing effective interventions to prevent and treat AF.
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256
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López-Crisosto C, Bravo-Sagua R, Rodriguez-Peña M, Mera C, Castro PF, Quest AFG, Rothermel BA, Cifuentes M, Lavandero S. ER-to-mitochondria miscommunication and metabolic diseases. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2096-105. [PMID: 26171812 DOI: 10.1016/j.bbadis.2015.07.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/09/2015] [Accepted: 07/10/2015] [Indexed: 12/17/2022]
Abstract
Eukaryotic cells contain a variety of subcellular organelles, each of which performs unique tasks. Thus follows that in order to coordinate these different intracellular functions, a highly dynamic system of communication must exist between the various compartments. Direct endoplasmic reticulum (ER)-mitochondria communication is facilitated by the physical interaction of their membranes in dedicated structural domains known as mitochondria-associated membranes (MAMs), which facilitate calcium (Ca(2+)) and lipid transfer between organelles and also act as platforms for signaling. Numerous studies have demonstrated the importance of MAM in ensuring correct function of both organelles, and recently MAMs have been implicated in the genesis of various human diseases. Here, we review the salient structural features of interorganellar communication via MAM and discuss the most common experimental techniques employed to assess functionality of these domains. Finally, we will highlight the contribution of MAM to a variety of cellular functions and consider the potential role of MAM in the genesis of metabolic diseases. In doing so, the importance for cell functions of maintaining appropriate communication between ER and mitochondria will be emphasized.
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Affiliation(s)
- Camila López-Crisosto
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Roberto Bravo-Sagua
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Marcelo Rodriguez-Peña
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Claudia Mera
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Pablo F Castro
- Advanced Center for Chronic Diseases (ACCDiS), Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8380492, Chile
| | - Andrew F G Quest
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Beverly A Rothermel
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75235, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Mariana Cifuentes
- Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago 7830490, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile; Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75235, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
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257
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Chigaev A. Does aberrant membrane transport contribute to poor outcome in adult acute myeloid leukemia? Front Pharmacol 2015; 6:134. [PMID: 26191006 PMCID: PMC4489100 DOI: 10.3389/fphar.2015.00134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/15/2015] [Indexed: 12/31/2022] Open
Abstract
Acute myeloid leukemia in adults is a highly heterogeneous disease. Gene expression profiling performed using unsupervised algorithms can be used to distinguish specific groups of patients within a large patient cohort. The identified gene expression signatures can offer insights into underlying physiological mechanisms of disease pathogenesis. Here, the analysis of several related gene expression clusters associated with poor outcome, worst overall survival and highest rates of resistant disease and obtained from the patients at the time of diagnosis or from previously untreated individuals is presented. Surprisingly, these gene clusters appear to be enriched for genes corresponding to proteins involved in transport across membranes (transporters, carriers and channels). Several ideas describing the possible relationship of membrane transport activity and leukemic cell biology, including the "Warburg effect," the specific role of chloride ion transport, direct "import" of metabolic energy through uptake of creatine phosphate, and modification of the bone marrow niche microenvironment are discussed.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, University of New Mexico Albuquerque, NM, USA
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258
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Abstract
Many protists with high ecological and medical relevance harbor plastids surrounded by four membranes. Thus, nucleus-encoded proteins of these complex plastids have to traverse these barriers. Here we report on the identification of the protein translocators located in two of the plastid surrounding membranes and present recent findings on the mechanisms of protein import into the plastids of diatoms.
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259
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Abstract
Mitochondrial function is key for maintaining cellular health, while mitochondrial failure is associated with various pathologies, including inherited metabolic disorders and age-related diseases. In order to maintain mitochondrial quality, several pathways of mitochondrial quality control have evolved. These systems monitor mitochondrial integrity through antioxidants, DNA repair systems, and chaperones and proteases involved in the mitochondrial unfolded protein response. Additional regulation of mitochondrial function involves dynamic exchange of components through mitochondrial fusion and fission. Sustained stress induces a selective autophagy - termed mitophagy - and ultimately leads to apoptosis. Together, these systems form a network that acts on the molecular, organellar, and cellular level. In this review, we highlight how these systems are regulated in an integrated context- and time-dependent network of mitochondrial quality control that is implicated in healthy aging.
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Affiliation(s)
- Ntsiki M Held
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, the Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, the Netherlands
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260
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Abstract
Mitochondria cannot be made de novo, so pre-existing mitochondria must be inherited at each cell division. A new study demonstrates cell-cycle-dependent regulation of the activity of the TOM translocase complex to induce mitochondrial biogenesis during the M phase of the cell cycle.
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261
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Hua R, Gidda SK, Aranovich A, Mullen RT, Kim PK. Multiple Domains in PEX16 Mediate Its Trafficking and Recruitment of Peroxisomal Proteins to the ER. Traffic 2015; 16:832-52. [PMID: 25903784 DOI: 10.1111/tra.12292] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/09/2015] [Accepted: 04/09/2015] [Indexed: 12/27/2022]
Abstract
Peroxisomes rely on a diverse array of mechanisms to ensure the specific targeting of their protein constituents. Peroxisomal membrane proteins (PMPs), for instance, are targeted by at least two distinct pathways: directly to peroxisomes from their sites of synthesis in the cytosol or indirectly via the endoplasmic reticulum (ER). However, the extent to which each PMP targeting pathway is involved in the maintenance of pre-existing peroxisomes is unclear. Recently, we showed that human PEX16 plays a critical role in the ER-dependent targeting of PMPs by mediating the recruitment of two other PMPs, PEX3 and PMP34, to the ER. Here, we extend these results by carrying out a comprehensive mutational analysis of PEX16 aimed at gaining insights into the molecular targeting signals responsible for its ER-to-peroxisome trafficking and the domain(s) involved in PMP recruitment function at the ER. We also show that the recruitment of PMPs to the ER by PEX16 is conserved in plants. The implications of these results in terms of the function of PEX16 and the role of the ER in peroxisome maintenance in general are discussed.
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Affiliation(s)
- Rong Hua
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5G 1A8
| | - Satinder K Gidda
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Alexander Aranovich
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 0A4
| | - Robert T Mullen
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Peter K Kim
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5G 1A8
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262
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Cherry AD, Piantadosi CA. Regulation of mitochondrial biogenesis and its intersection with inflammatory responses. Antioxid Redox Signal 2015; 22:965-76. [PMID: 25556935 PMCID: PMC4390030 DOI: 10.1089/ars.2014.6200] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria play a vital role in cellular homeostasis and are susceptible to damage from inflammatory mediators released by the host defense. Cellular recovery depends, in part, on mitochondrial quality control programs, including mitochondrial biogenesis. RECENT ADVANCES Early-phase inflammatory mediator proteins interact with PRRs to activate NF-κB-, MAPK-, and PKB/Akt-dependent pathways, resulting in increased expression or activity of coactivators and transcription factors (e.g., PGC-1α, NRF-1, NRF-2, and Nfe2l2) that regulate mitochondrial biogenesis. Inflammatory upregulation of NOS2-induced NO causes mitochondrial dysfunction, but NO is also a signaling molecule upregulating mitochondrial biogenesis via PGC-1α, participating in Nfe2l2-mediated antioxidant gene expression and modulating inflammation. NO and reactive oxygen species generated by the host inflammatory response induce the redox-sensitive HO-1/CO system, causing simultaneous induction of mitochondrial biogenesis and antioxidant gene expression. CRITICAL ISSUES Recent evidence suggests that mitochondrial biogenesis and mitophagy are coupled through redox pathways; for instance, parkin, which regulates mitophagy in chronic inflammation, may also modulate mitochondrial biogenesis and is upregulated through NF-κB. Further research on parkin in acute inflammation is ongoing. This highlights certain common features of the host response to acute and chronic inflammation, but caution is warranted in extrapolating findings across inflammatory conditions. FUTURE DIRECTIONS Inflammatory mitochondrial dysfunction and oxidative stress initiate further inflammatory responses through DAMP/PRR interactions and by inflammasome activation, stimulating mitophagy. A deeper understanding of mitochondrial quality control programs' impact on intracellular inflammatory signaling will improve our approach to the restoration of mitochondrial homeostasis in the resolution of acute inflammation.
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Affiliation(s)
- Anne D Cherry
- 1 Department of Anesthesiology, Duke University Medical Center , Durham, North Carolina
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263
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Schulz AM, Haynes CM. UPR(mt)-mediated cytoprotection and organismal aging. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1448-56. [PMID: 25857997 DOI: 10.1016/j.bbabio.2015.03.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/25/2015] [Accepted: 03/28/2015] [Indexed: 12/20/2022]
Abstract
Time- or age-dependent accumulation of mitochondrial damage and dysfunction is strongly associated with aging [1]. Thus, a major biomedical goal is to identify and therapeutically manipulate those inherent programs that protect against mitochondrial dysfunction to promote cell survival and organismal health. The mitochondrial unfolded protein response (UPR(mt)) is such a protective transcriptional response mediated by mitochondrial-to-nuclear signaling that includes mitochondrial proteostasis genes to stabilize mitochondrial function, metabolic adaptations, as well as an innate immunity program. Here, we review the UPR(mt) and its role during a variety of forms of mitochondrial dysfunction including those caused by mutations in respiratory chain genes as well as upon exposure to pathogens that produce mitochondrial toxins. We also review recent data in support of and against the emerging role of the UPR(mt) during aging and longevity. This article is part of a Special Issue entitled: Mitochondrial Dysfunction in Aging.
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Affiliation(s)
- Anna M Schulz
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
| | - Cole M Haynes
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; BCMB Allied Program, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.
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264
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Pellegrino MW, Haynes CM. Mitophagy and the mitochondrial unfolded protein response in neurodegeneration and bacterial infection. BMC Biol 2015; 13:22. [PMID: 25857750 PMCID: PMC4384303 DOI: 10.1186/s12915-015-0129-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are highly dynamic and structurally complex organelles that provide multiple essential metabolic functions. Mitochondrial dysfunction is associated with neurodegenerative conditions such as Parkinson’s disease, as well as bacterial infection. Here, we explore the roles of mitochondrial autophagy (mitophagy) and the mitochondrial unfolded protein response (UPRmt) in the response to mitochondrial dysfunction, focusing in particular on recent evidence on the role of mitochondrial import efficiency in the regulation of these stress pathways and how they may interact to protect the mitochondrial pool while initiating an innate immune response to protect against bacterial pathogens.
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265
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Metabolic control via the mitochondrial protein import machinery. Curr Opin Cell Biol 2015; 33:42-8. [DOI: 10.1016/j.ceb.2014.11.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/16/2014] [Indexed: 12/19/2022]
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266
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Ren Y, Chen S, Ma M, Yao X, Sun D, Li B, Lu J. The activation of protein homeostasis protective mechanisms perhaps is not responsible for lifespan extension caused by deficiencies of mitochondrial proteins in C. elegans. Exp Gerontol 2015; 65:53-7. [PMID: 25769692 DOI: 10.1016/j.exger.2015.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 03/05/2015] [Accepted: 03/08/2015] [Indexed: 12/28/2022]
Abstract
During aging the ability of organisms to maintain the protein homeostasis declines and damaged and misfolded proteins accumulate in cells. But whether the deterioration of protein homeostasis is the cause or consequence of aging is not clearly understood. Mitochondrial dysfunctions usually lead to increased longevity in Caenorhabditis elegans, the cause of which is believed to be the activation of protein homeostasis protective mechanisms including mitochondrial unfolded protein response (UPR(mt)) and GCN-2 kinase mediated nutrient-sensing pathway. However, we investigated four genes which encode well-defined mitochondrial proteins and found that: (i) UPR(mt) activation was associated with not only increased longevity by knockdown of mfn-1, cco-1, or nuo-6, but also decreased longevity by mev-1 RNAi; (ii) The blockage of UPR(mt) pathway did not repress mfn-1, cco-1, or nuo-6 RNAi induced lifespan extension; (iii) The activation of UPR(mt) did not increase longevity; (iv) Knockdown of mfn-1, cco-1, or nuo-6 increased longevity independently of GCN-2. The combined results indicate that two important kinds of the protein homeostasis protective mechanisms, namely UPR(mt) and GCN-2 pathways, are not responsible for mitochondrial deficiency induced lifespan extension. The enhanced protection of protein homeostasis may be insufficient to slow aging, and there may be other mechanisms that contribute to the increased longevity in response to mitochondrial dysfunctions.
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Affiliation(s)
- Yaguang Ren
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Sixi Chen
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Mengmeng Ma
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Xiuping Yao
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Dayan Sun
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Bin Li
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Jianxin Lu
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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267
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Braun RJ, Sommer C, Leibiger C, Gentier RJG, Dumit VI, Paduch K, Eisenberg T, Habernig L, Trausinger G, Magnes C, Pieber T, Sinner F, Dengjel J, van Leeuwen FW, Kroemer G, Madeo F. Accumulation of Basic Amino Acids at Mitochondria Dictates the Cytotoxicity of Aberrant Ubiquitin. Cell Rep 2015; 10:1557-1571. [PMID: 25753421 PMCID: PMC4407011 DOI: 10.1016/j.celrep.2015.02.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 12/23/2014] [Accepted: 01/31/2015] [Indexed: 12/02/2022] Open
Abstract
Neuronal accumulation of UBB+1, a frameshift variant of ubiquitin B, is a hallmark of Alzheimer’s disease (AD). How UBB+1 contributes to neuronal dysfunction remains elusive. Here, we show that in brain regions of AD patients with neurofibrillary tangles UBB+1 co-exists with VMS1, the mitochondrion-specific component of the ubiquitin-proteasome system (UPS). Expression of UBB+1 in yeast disturbs the UPS, leading to mitochondrial stress and apoptosis. Inhibiting UPS activity exacerbates while stimulating UPS by the transcription activator Rpn4 reduces UBB+1-triggered cytotoxicity. High levels of the Rpn4 target protein Cdc48 and its cofactor Vms1 are sufficient to relieve programmed cell death. We identified the UBB+1-induced enhancement of the basic amino acids arginine, ornithine, and lysine at mitochondria as a decisive toxic event, which can be reversed by Cdc48/Vms1-mediated proteolysis. The fact that AD-induced cellular dysfunctions can be avoided by UPS activity at mitochondria has potentially far-reaching pathophysiological implications. UBB+1 co-exists with the UPS component VMS1 in neurofibrillary tangles UBB+1 accumulation impairs the UPS and mitochondria, triggering cell death UBB+1 causes accumulation of basic amino acids at mitochondria Vms1 reverts UBB+1-triggered basic amino acid accumulation and cell death
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Affiliation(s)
- Ralf J Braun
- Institute of Cell Biology, University of Bayreuth, 95440 Bayreuth, Germany.
| | - Cornelia Sommer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Christine Leibiger
- Institute of Cell Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Romina J G Gentier
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Verónica I Dumit
- FRIAS Freiburg Institute for Advanced Studies, Department of Dermatology, Medical Center, ZBSA Center for Biological Systems Analysis, BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Katrin Paduch
- Institute of Cell Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Lukas Habernig
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Gert Trausinger
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, 8010 Graz, Austria
| | - Christoph Magnes
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, 8010 Graz, Austria
| | - Thomas Pieber
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, 8010 Graz, Austria; Division of Endocrinology and Metabolism, Medical University of Graz, 8036 Graz, Austria
| | - Frank Sinner
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, 8010 Graz, Austria; Division of Endocrinology and Metabolism, Medical University of Graz, 8036 Graz, Austria
| | - Jörn Dengjel
- FRIAS Freiburg Institute for Advanced Studies, Department of Dermatology, Medical Center, ZBSA Center for Biological Systems Analysis, BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Fred W van Leeuwen
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Guido Kroemer
- Apoptosis, Cancer and Immunity Laboratory, Team 11, Equipe labellisée Ligue contre le Cancer, INSERM Cordeliers Research Cancer, 75006 Paris, France; Cell Biology and Metabolomics Platforms, Gustave Roussy Comprehensive Cancer Center, 94805 Villejuif, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, 75015 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75005 Paris, France
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
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268
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A Perspective on Transport of Proteins into Mitochondria: A Myriad of Open Questions. J Mol Biol 2015; 427:1135-58. [DOI: 10.1016/j.jmb.2015.02.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/22/2022]
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269
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Abstract
Metabolic remodeling is a major determinant for many cell fate decisions, and a switch from respiration to aerobic glycolysis is generally considered as a hallmark of cancer cell transformation. Pyruvate is a key metabolite at the major junction of carbohydrate metabolism between cytosolic glycolysis and the mitochondrial Krebs cycle. In this issue of The EMBO Journal, Bender et al show that yeast cells regulate pyruvate uptake into mitochondria, and thus its metabolic fate, by expressing alternative pyruvate carrier complexes with different activities.
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Affiliation(s)
- Heike Rampelt
- Institut für Biochemie und Molekularbiologie, Universität Freiburg, Freiburg, Germany
| | - Martin van der Laan
- Institut für Biochemie und Molekularbiologie, Universität Freiburg, Freiburg, Germany BIOSS Centre for Biological Signalling Studies, Universität Freiburg, Freiburg, Germany
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270
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Eiyama A, Okamoto K. PINK1/Parkin-mediated mitophagy in mammalian cells. Curr Opin Cell Biol 2015; 33:95-101. [PMID: 25697963 DOI: 10.1016/j.ceb.2015.01.002] [Citation(s) in RCA: 388] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 01/09/2015] [Indexed: 12/11/2022]
Abstract
Mitochondria-specific autophagy (mitophagy) is a fundamental process critical for maintaining mitochondrial fitness in a myriad of cell types. Particularly, mitophagy contributes to mitochondrial quality control by selectively eliminating dysfunctional mitochondria. In mammalian cells, the Ser/Thr kinase PINK1 and the E3 ubiquitin ligase Parkin act cooperatively in sensing mitochondrial functional state and marking damaged mitochondria for disposal via the autophagy pathway. Notably, ubiquitin and deubiquitinases play vital roles in modulating Parkin activity and mitophagy efficiency. In this review, we highlight recent breakthroughs addressing the key issues of how PINK1 activates Parkin in response to mitochondrial malfunction, how Parkin localizes specifically to impaired mitochondria, and how ubiquitination and deubiquitination regulate PINK1/Parkin-mediated mitophagy.
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Affiliation(s)
- Akinori Eiyama
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Koji Okamoto
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
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271
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Horvath SE, Rampelt H, Oeljeklaus S, Warscheid B, van der Laan M, Pfanner N. Role of membrane contact sites in protein import into mitochondria. Protein Sci 2015; 24:277-97. [PMID: 25514890 DOI: 10.1002/pro.2625] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/08/2014] [Indexed: 12/13/2022]
Abstract
Mitochondria import more than 1,000 different proteins from the cytosol. The proteins are synthesized as precursors on cytosolic ribosomes and are translocated by protein transport machineries of the mitochondrial membranes. Five main pathways for protein import into mitochondria have been identified. Most pathways use the translocase of the outer mitochondrial membrane (TOM) as the entry gate into mitochondria. Depending on specific signals contained in the precursors, the proteins are subsequently transferred to different intramitochondrial translocases. In this article, we discuss the connection between protein import and mitochondrial membrane architecture. Mitochondria possess two membranes. It is a long-standing question how contact sites between outer and inner membranes are formed and which role the contact sites play in the translocation of precursor proteins. A major translocation contact site is formed between the TOM complex and the presequence translocase of the inner membrane (TIM23 complex), promoting transfer of presequence-carrying preproteins to the mitochondrial inner membrane and matrix. Recent findings led to the identification of contact sites that involve the mitochondrial contact site and cristae organizing system (MICOS) of the inner membrane. MICOS plays a dual role. It is crucial for maintaining the inner membrane cristae architecture and forms contacts sites to the outer membrane that promote translocation of precursor proteins into the intermembrane space and outer membrane of mitochondria. The view is emerging that the mitochondrial protein translocases do not function as independent units, but are embedded in a network of interactions with machineries that control mitochondrial activity and architecture.
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Affiliation(s)
- Susanne E Horvath
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104, Freiburg, Germany
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272
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Audano M, Ferrari A, Fiorino E, Kuenzl M, Caruso D, Mitro N, Crestani M, De Fabiani E. Energizing Genetics and Epi-genetics: Role in the Regulation of Mitochondrial Function. Curr Genomics 2015; 15:436-56. [PMID: 25646072 PMCID: PMC4311388 DOI: 10.2174/138920291506150106151119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/11/2014] [Accepted: 11/18/2014] [Indexed: 12/15/2022] Open
Abstract
Energy metabolism and mitochondrial function hold a core position in cellular homeostasis. Oxidative metabolism is regulated at multiple levels, ranging from gene transcription to allosteric modulation. To accomplish the fine tuning of these multiple regulatory circuits, the nuclear and mitochondrial compartments are tightly and reciprocally controlled. The fact that nuclear encoded factors, PPARγ coactivator 1α and mitochondrial transcription factor A, play pivotal roles in the regulation of oxidative metabolism and mitochondrial biogenesis is paradigmatic of this crosstalk. Here we provide an updated survey of the genetic and epigenetic mechanisms involved in the control of energy metabolism and mitochondrial function. Chromatin dynamics highly depends on post-translational modifications occurring at specific amino acids in histone proteins and other factors associated to nuclear DNA. In addition to the well characterized enzymes responsible for histone methylation/demethylation and acetylation/deacetylation, other factors have gone on the "metabolic stage". This is the case of the new class of α-ketoglutarate-regulated demethylases (Jumonji C domain containing demethylases) and of the NAD+-dependent deacetylases, also known as sirtuins. Moreover, unexpected features of the machineries involved in mitochondrial DNA (mtDNA) replication and transcription, mitochondrial RNA processing and maturation have recently emerged. Mutations or defects of any component of these machineries profoundly affect mitochondrial activity and oxidative metabolism. Finally, recent evidences support the importance of mtDNA packaging in replication and transcription. These observations, along with the discovery that non-classical CpG islands present in mtDNA undergo methylation, indicate that epigenetics also plays a role in the regulation of the mitochondrial genome function.
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Affiliation(s)
- Matteo Audano
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Alessandra Ferrari
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Erika Fiorino
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Martin Kuenzl
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Donatella Caruso
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Nico Mitro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Maurizio Crestani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
| | - Emma De Fabiani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy
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273
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274
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Patrushev MV, Kamenski PA, Mazunin IO. Mutations in mitochondrial DNA and approaches for their correction. BIOCHEMISTRY (MOSCOW) 2014; 79:1151-60. [DOI: 10.1134/s0006297914110029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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275
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Kalderon B, Pines O. Protein folding as a driving force for dual protein targeting in eukaryotes. Front Mol Biosci 2014; 1:23. [PMID: 25988164 PMCID: PMC4428415 DOI: 10.3389/fmolb.2014.00023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/28/2014] [Indexed: 01/19/2023] Open
Abstract
It is well documented that in eukaryotic cells molecules of one protein can be located in several subcellular locations, a phenomenon termed dual targeting, dual localization, or dual distribution. The differently localized identical or nearly identical proteins are termed “echoforms.” Our conventional definition of dual targeted proteins refers to situations in which one of the echoforms is translocated through/into a membrane. Thus, dual targeted proteins are recognized by at least one organelle's receptors and translocation machineries within the lipid bilayer. In this review we attempt to evaluate mechanisms and situations in which protein folding is the major determinant of dual targeting and of the relative distribution levels of echoforms in the subcellular compartments of the eukaryotic cell. We show that the decisive folding step can occur prior, during or after translocation through the bilayer of a biological membrane. This phenomenon involves folding catalysts in the cell such as chaperones, proteases and modification enzymes, and targeting processes such as signal recognition, translocation through membranes, trapping, retrotranslocation and reverse translocation.
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Affiliation(s)
- Bella Kalderon
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem Jerusalem, Israel
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem Jerusalem, Israel ; CREATE-NUS-HUJ Cellular and Molecular Mechanisms of Inflammation Program, National University of Singapore Singapore, Singapore
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276
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Mgr2 functions as lateral gatekeeper for preprotein sorting in the mitochondrial inner membrane. Mol Cell 2014; 56:641-52. [PMID: 25454944 DOI: 10.1016/j.molcel.2014.10.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/14/2014] [Accepted: 10/09/2014] [Indexed: 11/21/2022]
Abstract
The majority of preproteins destined for mitochondria carry N-terminal presequences. The presequence translocase of the inner mitochondrial membrane (TIM23 complex) plays a central role in protein sorting. Preproteins are either translocated through the TIM23 complex into the matrix or are laterally released into the inner membrane. We report that the small hydrophobic protein Mgr2 controls the lateral release of preproteins. Mgr2 interacts with preproteins in transit through the TIM23 complex. Overexpression of Mgr2 delays preprotein release, whereas a lack of Mgr2 promotes preprotein sorting into the inner membrane. Preproteins with a defective inner membrane sorting signal are translocated into the matrix in wild-type mitochondria but are released into the inner membrane in Mgr2-deficient mitochondria. We conclude that Mgr2 functions as a lateral gatekeeper of the mitochondrial presequence translocase, providing quality control for the membrane sorting of preproteins.
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277
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Evidence to support mitochondrial neuroprotection, in severe traumatic brain injury. J Bioenerg Biomembr 2014; 47:133-48. [PMID: 25358440 DOI: 10.1007/s10863-014-9589-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/13/2014] [Indexed: 12/22/2022]
Abstract
Traumatic brain injury (TBI) is still the leading cause of disability in young adults worldwide. The major mechanisms - diffuse axonal injury, cerebral contusion, ischemic neurological damage, and intracranial hematomas have all been shown to be associated with mitochondrial dysfunction in some form. Mitochondrial dysfunction in TBI patients is an active area of research, and attempts to manipulate neuronal/astrocytic metabolism to improve outcomes have been met with limited translational success. Previously, several preclinical and clinical studies on TBI induced mitochondrial dysfunction have focused on opening of the mitochondrial permeability transition pore (PTP), consequent neurodegeneration and attempts to mitigate this degeneration with cyclosporine A (CsA) or analogous drugs, and have been unsuccessful. Recent insights into normal mitochondrial dynamics and into diseases such as inherited mitochondrial neuropathies, sepsis and organ failure could provide novel opportunities to develop mitochondria-based neuroprotective treatments that could improve severe TBI outcomes. This review summarizes those aspects of mitochondrial dysfunction underlying TBI pathology with special attention to models of penetrating traumatic brain injury, an epidemic in modern American society.
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278
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Höhr AIC, Straub SP, Warscheid B, Becker T, Wiedemann N. Assembly of β-barrel proteins in the mitochondrial outer membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:74-88. [PMID: 25305573 DOI: 10.1016/j.bbamcr.2014.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 09/25/2014] [Accepted: 10/01/2014] [Indexed: 12/15/2022]
Abstract
Mitochondria evolved through endosymbiosis of a Gram-negative progenitor with a host cell to generate eukaryotes. Therefore, the outer membrane of mitochondria and Gram-negative bacteria contain pore proteins with β-barrel topology. After synthesis in the cytosol, β-barrel precursor proteins are first transported into the mitochondrial intermembrane space. Folding and membrane integration of β-barrel proteins depend on the mitochondrial sorting and assembly machinery (SAM) located in the outer membrane, which is related to the β-barrel assembly machinery (BAM) in bacteria. The SAM complex recognizes β-barrel proteins by a β-signal in the C-terminal β-strand that is required to initiate β-barrel protein insertion into the outer membrane. In addition, the SAM complex is crucial to form membrane contacts with the inner mitochondrial membrane by interacting with the mitochondrial contact site and cristae organizing system (MICOS) and shares a subunit with the endoplasmic reticulum-mitochondria encounter structure (ERMES) that links the outer mitochondrial membrane to the endoplasmic reticulum (ER).
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Affiliation(s)
- Alexandra I C Höhr
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany
| | - Sebastian P Straub
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany; Abteilung Biochemie und Funktionelle Proteomik, Institut für Biologie II, Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany
| | - Thomas Becker
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany
| | - Nils Wiedemann
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany.
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279
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Rainbolt TK, Saunders JM, Wiseman RL. Stress-responsive regulation of mitochondria through the ER unfolded protein response. Trends Endocrinol Metab 2014; 25:528-37. [PMID: 25048297 DOI: 10.1016/j.tem.2014.06.007] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 12/31/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria form physical interactions involved in the regulation of biologic functions including mitochondrial bioenergetics and apoptotic signaling. To coordinate these functions during stress, cells must coregulate ER and mitochondria through stress-responsive signaling pathways such as the ER unfolded protein response (UPR). Although the UPR is traditionally viewed as a signaling pathway responsible for regulating ER proteostasis, it is becoming increasingly clear that the protein kinase RNA (PKR)-like endoplasmic reticulum kinase (PERK) signaling pathway within the UPR can also regulate mitochondria proteostasis and function in response to pathologic insults that induce ER stress. Here, we discuss the contributions of PERK in coordinating ER-mitochondrial activities and describe the mechanisms by which PERK adapts mitochondrial proteostasis and function in response to ER stress.
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Affiliation(s)
- T Kelly Rainbolt
- Department of Molecular and Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jaclyn M Saunders
- Department of Molecular and Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - R Luke Wiseman
- Department of Molecular and Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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280
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Tantibhedhyangkul J, Hawkins KC, Dai Q, Mu K, Dunn CN, Miller SE, Price TM. Expression of a mitochondrial progesterone receptor in human spermatozoa correlates with a progestin-dependent increase in mitochondrial membrane potential. Andrology 2014; 2:875-83. [PMID: 25187426 DOI: 10.1111/j.2047-2927.2014.00263.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 12/23/2022]
Abstract
The hyperactivation of human spermatozoa necessary for fertilization requires a substantial increase in cellular energy production. The factors responsible for increasing cellular energy remain poorly defined. This article proposes a role for a novel mitochondrial progesterone receptor (PR-M) in modulation of mitochondrial activity. Basic science studies demonstrate a 38 kDa protein with western blot analysis, consistent with PR-M; whereas imaging studies with confocal and immunoelectron microscopy demonstrate a PR on the mitochondria. Treatment with a PR-specific progestin shows increased mitochondrial membrane potential, not related to induction of an acrosome reaction. The increase in mitochondrial membrane potential was inhibited by a specific PR antagonist, but not affected by an inhibitor to the progesterone-dependent Catsper voltage-activated channel. In conclusion, these studies suggest expression of a novel mitochondrial PR in human spermatozoa with a progestin-dependent increase in mitochondrial activity. This mechanism may serve to enhance cellular energy production as the spermatozoa traverse the female genital tract being exposed to increasing concentrations of progesterone.
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281
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Shan H, Wei J, Zhang M, Lin L, Yan R, Zhu Y, Zhang R. Calreticulin is localized at mitochondria of rat cardiomyocytes and affected by furazolidone. Mol Cell Biochem 2014; 397:125-30. [PMID: 25087122 DOI: 10.1007/s11010-014-2179-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 07/24/2014] [Indexed: 11/29/2022]
Abstract
Calreticulin (CRT) is a calcium-buffering protein which is predominantly located in endoplasmic reticulum. In the previous mitochondria proteome analysis, we accidentally found that CRT may be also localized at myocardial mitochondria and was upregulated in a rat model of furazolidone-induced dilated cardiomyopathy. To our knowledge, there has not yet been any report of its presence in mitochondria of any cell types. The present study aimed to determine whether CRT was located at the mitochondria of rat cardiomyocytes and whether the mitochondrial CRT was affected by furazolidone. Mitochondrial preparations were isolated from primary cultured neonatal rat cardiomyocytes and purified by differential centrifugation. The purity of mitochondria was assessed by the reduction or elimination of the immunoreactivities of markers for cytosol, nucleus, sarcolemma, and endoplasmic reticulum. Western blot analysis demonstrated the presence of CRT in purified mitochondria of rat cardiomyocytes. The distribution of CRT to mitochondria was further confirmed by immuno-electron microscopy, flow cytometry, and laser scanning confocal microscopy (double staining with MitoTracker Red and CRT-Alexa Fluor 488). Western blot analysis also demonstrated that the mitochondrial content of CRT was significantly enhanced by furazolidone treatment by 2.73 ± 0.13 fold (P < 0.05) in rat cardiomyocytes, which was verified by immuno-electron microscopy. In summary, the present results suggest that CRT is localized at mitochondria of rat cardiomyocytes and such localization is affected by furazolidone.
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Affiliation(s)
- Hu Shan
- Department of Cardiology, The Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
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282
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Lackey SWK, Taylor RD, Go NE, Wong A, Sherman EL, Nargang FE. Evidence supporting the 19 β-strand model for Tom40 from cysteine scanning and protease site accessibility studies. J Biol Chem 2014; 289:21640-50. [PMID: 24947507 DOI: 10.1074/jbc.m114.578765] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Most proteins found in mitochondria are translated in the cytosol and enter the organelle via the TOM complex (translocase of the outer mitochondrial membrane). Tom40 is the pore forming component of the complex. Although the three-dimensional structure of Tom40 has not been determined, the structure of porin, a related protein, has been shown to be a β-barrel containing 19 membrane spanning β-strands and an N-terminal α-helical region. The evolutionary relationship between the two proteins has allowed modeling of Tom40 into a similar structure by several laboratories. However, it has been suggested that the 19-strand porin structure does not represent the native form of the protein. If true, modeling of Tom40 based on the porin structure would also be invalid. We have used substituted cysteine accessibility mapping to identify several potential β-strands in the Tom40 protein in isolated mitochondria. These data, together with protease accessibility studies, support the 19 β-strand model for Tom40 with the C-terminal end of the protein localized to the intermembrane space.
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Affiliation(s)
- Sebastian W K Lackey
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Rebecca D Taylor
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Nancy E Go
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Annie Wong
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - E Laura Sherman
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Frank E Nargang
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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283
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Deckers M, Balleininger M, Vukotic M, Römpler K, Bareth B, Juris L, Dudek J. Aim24 stabilizes respiratory chain supercomplexes and is required for efficient respiration. FEBS Lett 2014; 588:2985-92. [PMID: 24928273 DOI: 10.1016/j.febslet.2014.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/24/2014] [Accepted: 06/02/2014] [Indexed: 10/25/2022]
Abstract
The mitochondrial respiratory chain is essential for the conversion of energy derived from the oxidation of metabolites into the membrane potential, which drives the synthesis of ATP. The electron transporting complexes bc1 complex and the cytochrome c oxidase assemble into large supercomplexes, allowing efficient energy transduction. Currently, we have only limited information about what determines the structure of the supercomplex. Here, we characterize Aim24 in baker's yeast as a protein, which is integrated in the mitochondrial inner membrane and is required for the structural integrity of the supercomplex. Deletion of AIM24 strongly affects activity of the respiratory chain and induces a growth defect on non-fermentable medium. Our data indicate that Aim24 has a function in stabilizing the respiratory chain supercomplexes.
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Affiliation(s)
- Markus Deckers
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany
| | - Martina Balleininger
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany
| | - Milena Vukotic
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany
| | - Katharina Römpler
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany
| | - Bettina Bareth
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany
| | - Lisa Juris
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany
| | - Jan Dudek
- Department of Cellular Biochemistry, University of Göttingen, D-37073 Göttingen, Germany.
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284
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Mitochondrial pyruvate carrier 2 hypomorphism in mice leads to defects in glucose-stimulated insulin secretion. Cell Rep 2014; 7:2042-2053. [PMID: 24910426 DOI: 10.1016/j.celrep.2014.05.017] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 04/15/2014] [Accepted: 05/08/2014] [Indexed: 01/04/2023] Open
Abstract
Carrier-facilitated pyruvate transport across the inner mitochondrial membrane plays an essential role in anabolic and catabolic intermediary metabolism. Mitochondrial pyruvate carrier 2 (Mpc2) is believed to be a component of the complex that facilitates mitochondrial pyruvate import. Complete MPC2 deficiency resulted in embryonic lethality in mice. However, a second mouse line expressing an N-terminal truncated MPC2 protein (Mpc2(Δ16)) was viable but exhibited a reduced capacity for mitochondrial pyruvate oxidation. Metabolic studies demonstrated exaggerated blood lactate concentrations after pyruvate, glucose, or insulin challenge in Mpc2(Δ16) mice. Additionally, compared with wild-type controls, Mpc2(Δ16) mice exhibited normal insulin sensitivity but elevated blood glucose after bolus pyruvate or glucose injection. This was attributable to reduced glucose-stimulated insulin secretion and was corrected by sulfonylurea KATP channel inhibitor administration. Collectively, these data are consistent with a role for MPC2 in mitochondrial pyruvate import and suggest that Mpc2 deficiency results in defective pancreatic β cell glucose sensing.
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285
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Mottis A, Jovaisaite V, Auwerx J. The mitochondrial unfolded protein response in mammalian physiology. Mamm Genome 2014; 25:424-33. [PMID: 24898297 DOI: 10.1007/s00335-014-9525-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/06/2014] [Indexed: 12/27/2022]
Abstract
Mitochondria, the main site of cellular energy harvesting, are derived from proteobacteria that evolved within our cells in endosymbiosis. Mitochondria retained vestiges of their proteobacterial genome, the circular mitochondrial DNA, which encodes 13 subunits of the oxidative phosphorylation multiprotein complexes in the electron transport chain (ETC), while the remaining ~80 ETC components are encoded in the nuclear DNA (nDNA). A further ~1,400 proteins, which are essential for mitochondrial function are also encoded in nDNA. Thus, a majority of mitochondrial proteins are translated in the cytoplasm, then imported, processed, and assembled in the mitochondria. An intricate protein quality control (PQC) network, constituted of chaperones and proteases that refold or degrade defective proteins, maintains mitochondrial proteostasis and ensures the cell and organism health. The mitochondrial unfolded protein response is a relatively recently discovered PQC pathway, which senses the proteostatic disturbances specifically in the mitochondria and resolves the stress by retrograde signaling to the nucleus and consequent transcriptional activation of protective genes. This PQC system does not only transiently resolve the local stress but also can have long-lasting effects on whole body metabolism, fitness, and longevity. A delicate tuning of its activation levels might constitute a treatment of various diseases, such as metabolic diseases, cancer, and neurodegenerative disorders.
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Affiliation(s)
- Adrienne Mottis
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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286
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Differential targeting of VDAC3 mRNA isoforms influences mitochondria morphology. Proc Natl Acad Sci U S A 2014; 111:8991-6. [PMID: 24889622 DOI: 10.1073/pnas.1402588111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Intracellular targeting of mRNAs has recently emerged as a prevalent mechanism to control protein localization. For mitochondria, a cotranslational model of protein import is now proposed in parallel to the conventional posttranslational model, and mitochondrial targeting of mRNAs has been demonstrated in various organisms. Voltage-dependent anion channels (VDACs) are the most abundant proteins in the outer mitochondrial membrane and the major transport pathway for numerous metabolites. Four nucleus-encoded VDACs have been identified in Arabidopsis thaliana. Alternative cleavage and polyadenylation generate two VDAC3 mRNA isoforms differing by their 3' UTR. By using quantitative RT-PCR and in vivo mRNA visualization approaches, the two mRNA variants were shown differentially associated with mitochondria. The longest mRNA presents a 3' extension named alternative UTR (aUTR) that is necessary and sufficient to target VDAC3 mRNA to the mitochondrial surface. Moreover, aUTR is sufficient for the mitochondrial targeting of a reporter transcript, and can be used as a tool to target an unrelated mRNA to the mitochondrial surface. Finally, VDAC3-aUTR mRNA variant impacts mitochondria morphology and size, demonstrating the role of mRNA targeting in mitochondria biogenesis.
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287
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Mitochondrial protein translocases for survival and wellbeing. FEBS Lett 2014; 588:2484-95. [DOI: 10.1016/j.febslet.2014.05.028] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/15/2014] [Accepted: 05/15/2014] [Indexed: 11/20/2022]
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288
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Gottschalk WK, Lutz MW, He YT, Saunders AM, Burns DK, Roses AD, Chiba-Falek O. The Broad Impact of TOM40 on Neurodegenerative Diseases in Aging. ACTA ACUST UNITED AC 2014; 1. [PMID: 25745640 DOI: 10.13188/2376-922x.1000003] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondrial dysfunction is an important factor in the pathogenesis of age-related diseases, including neurodegenerative diseases like Alzheimer's and Parkinson's spectrum disorders. A polymorphism in Translocase of the Outer Mitochondrial Membrane - 40 kD (TOMM40) is associated with risk and age-of onset of late-onset AD, and is the only nuclear- encoded gene identified in genetic studies to date that presumably contributes to LOAD-related mitochondria dysfunction. In this review, we describe the TOM40-mediated mitochondrial protein import mechanism, and discuss the evidence linking TOM40 with Alzheimer's (AD) and Parkinson's (PD) diseases. All but 36 of the >~1,500 mitochondrial proteins are encoded by the nucleus and are synthesized on cytoplasmic ribosomes, and most of these are imported into mitochondria through the TOM complex, of which TOM40 is the central pore, mediating communication between the cytoplasm and the mitochondrial interior. APP enters and obstructs the TOM40 pore, inhibiting import of OXPHOS-related proteins and disrupting the mitochondrial redox balance. Other pathogenic proteins, such as Aβ and alpha-synuclein, readily pass through the pore and cause toxic effects by directly inhibiting mitochondrial enzymes. Healthy mitochondria normally import and degrade the PD-related protein Pink1, but Pink1 exits mitochondria if the membrane potential collapses and initiates Parkin-mediated mitophagy. Under normal circumstances, this process helps clear dysfunctional mitochondria and contributes to cellular health, but PINK1 mutations associated with PD exit mitochondria with intact membrane potentials, disrupting mitochondrial dynamics, leading to pathology. Thus, TOM40 plays a central role in the mitochondrial dysfunction that underlies age-related neurodegenerative diseases. Learning about the factors that control TOM40 levels and activity, and how TOM40, specifically, and the TOM complex, generally, interacts with potentially pathogenic proteins, will provide deeper insights to AD and PD pathogenesis, and possibly new targets for preventative and/or therapeutic treatments.
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Affiliation(s)
- William K Gottschalk
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael W Lutz
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Yu Ting He
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ann M Saunders
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Zinfandel Pharmaceuticals, Chapel Hill, NC, USA
| | | | - Allen D Roses
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Zinfandel Pharmaceuticals, Chapel Hill, NC, USA
| | - Ornit Chiba-Falek
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
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