1
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Li H, Gong W, Sun W, Yao Y, Han Y. Role of VPS39, a key tethering protein for endolysosomal trafficking and mitochondria-lysosome crosstalk, in health and disease. J Cell Biochem 2023. [PMID: 36924104 DOI: 10.1002/jcb.30396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/12/2023] [Accepted: 02/28/2023] [Indexed: 03/18/2023]
Abstract
The coordinated interaction between mitochondria and lysosomes, mainly manifested by mitophagy, mitochondria-derived vesicles, and direct physical contact, is essential for maintaining cellular life activities. The VPS39 subunit of the homotypic fusion and protein sorting complex could play a key role in the regulation of organelle dynamics, such as endolysosomal trafficking and mitochondria-vacuole/lysosome crosstalk, thus contributing to a variety of physiological functions. The abnormalities of VPS39 and related subunits have been reported to be involved in the pathological process of some diseases. Here, we analyze the potential mechanisms and the existing problems of VPS39 in regulating organelle dynamics, which, in turn, regulate physiological functions and disease pathogenesis, so as to provide new clues for facilitating the discovery of therapeutic targets for mitochondrial and lysosomal diseases.
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Affiliation(s)
- Hanbing Li
- Institute of Pharmacology, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Wenwen Gong
- Institute of Pharmacology, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Weiyun Sun
- Institute of Pharmacology, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Yuanfa Yao
- Institute of Pharmacology, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Yubing Han
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, China.,Britton Chance Center for Biomedical Photonics-MoE Key Laboratory for Biomedical Photonics, Advanced Biomedical Imaging Facility-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, China
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2
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Poosapati S, Ravulapalli PD, Viswanathaswamy DK, Kannan M. Proteomics of Two Thermotolerant Isolates of Trichoderma under High-Temperature Stress. J Fungi (Basel) 2021; 7:1002. [PMID: 34946985 PMCID: PMC8704589 DOI: 10.3390/jof7121002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 11/22/2022] Open
Abstract
Several species of the soil borne fungus of the genus Trichoderma are known to be versatile, opportunistic plant symbionts and are the most successful biocontrol agents used in today's agriculture. To be successful in field conditions, the fungus must endure varying climatic conditions. Studies have indicated that a high atmospheric temperature coupled with low humidity is a major factor in the inconsistent performance of Trichoderma under field conditions. Understanding the molecular modulations associated with Trichoderma that persist and deliver under abiotic stress conditions will aid in exploiting the value of these organisms for such uses. In this study, a comparative proteomic analysis, using two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption/time-of-flight (MALDI-TOF-TOF) mass spectrometry, was used to identify proteins associated with thermotolerance in two thermotolerant isolates of Trichoderma: T. longibrachiatum 673, TaDOR673 and T. asperellum 7316, TaDOR7316; with 32 differentially expressed proteins being identified. Sequence homology and conserved domains were used to identify these proteins and to assign a probable function to them. The thermotolerant isolate, TaDOR673, seemed to employ the stress signaling MAPK pathways and heat shock response pathways to combat the stress condition, whereas the moderately tolerant isolate, TaDOR7316, seemed to adapt to high-temperature conditions by reducing the accumulation of misfolded proteins through an unfolded protein response pathway and autophagy. In addition, there were unique, as well as common, proteins that were differentially expressed in the two isolates studied.
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Affiliation(s)
- Sowmya Poosapati
- Department of Plant Pathology, ICAR-Indian Institute of Oilseeds Research, Rajendranagar, Hyderabad 500030, India;
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Prasad Durga Ravulapalli
- Department of Plant Pathology, ICAR-Indian Institute of Oilseeds Research, Rajendranagar, Hyderabad 500030, India;
| | | | - Monica Kannan
- Proteomics Facility, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, India;
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3
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Zimmermann A, Madreiter-Sokolowski C, Stryeck S, Abdellatif M. Targeting the Mitochondria-Proteostasis Axis to Delay Aging. Front Cell Dev Biol 2021; 9:656201. [PMID: 33777963 PMCID: PMC7991595 DOI: 10.3389/fcell.2021.656201] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/22/2021] [Indexed: 01/18/2023] Open
Abstract
Human life expectancy continues to grow globally, and so does the prevalence of age-related chronic diseases, causing a huge medical and economic burden on society. Effective therapeutic options for these disorders are scarce, and even if available, are typically limited to a single comorbidity in a multifaceted dysfunction that inevitably affects all organ systems. Thus, novel therapies that target fundamental processes of aging itself are desperately needed. In this article, we summarize current strategies that successfully delay aging and related diseases by targeting mitochondria and protein homeostasis. In particular, we focus on autophagy, as a fundamental proteostatic process that is intimately linked to mitochondrial quality control. We present genetic and pharmacological interventions that effectively extend health- and life-span by acting on specific mitochondrial and pro-autophagic molecular targets. In the end, we delve into the crosstalk between autophagy and mitochondria, in what we refer to as the mitochondria-proteostasis axis, and explore the prospect of targeting this crosstalk to harness maximal therapeutic potential of anti-aging interventions.
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Affiliation(s)
- Andreas Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | | | - Sarah Stryeck
- Institute of Interactive Systems and Data Science, Graz University of Technology, Graz, Austria
| | - Mahmoud Abdellatif
- Department of Cardiology, Medical University of Graz, Graz, Austria.,Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France.,Centre de Recherche des Cordeliers, Equipe Labellisée Par la Ligue Contre le Cancer, Université de Paris, Sorbonne Université, INSERM U1138, Institut Universitaire de France, Paris, France
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4
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Mechanisms of mitochondrial cell death. Biochem Soc Trans 2021; 49:663-674. [PMID: 33704419 DOI: 10.1042/bst20200522] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 12/23/2022]
Abstract
Mitochondria are double-membrane bound organelles that not only provide energy for intracellular metabolism, but also play a key role in the regulation of cell death. Mitochondrial outer membrane permeabilization (MOMP), allowing the release of intermembrane space proteins like cytochrome c, is considered a point of no return in apoptosis. MOMP is controlled by the proteins of the B-cell lymphoma 2 (BCL-2) family, including pro-and anti-apoptotic members, whose balance determines the decision between cell death and survival. Other factors such as membrane lipid environment, membrane dynamics, and inter-organelle communications are also known to influence this process. MOMP and apoptosis have been acknowledged as immunologically silent. Remarkably, a growing body of evidence indicates that MOMP can engage in various pro-inflammatory signaling functions. In this mini-review, we discuss about our current knowledge on the mechanisms of mitochondrial apoptosis, as well as the involvement of mitochondria in other kinds of programmed cell death pathways.
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5
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Fritsch LE, Moore ME, Sarraf SA, Pickrell AM. Ubiquitin and Receptor-Dependent Mitophagy Pathways and Their Implication in Neurodegeneration. J Mol Biol 2020; 432:2510-2524. [PMID: 31689437 PMCID: PMC7195237 DOI: 10.1016/j.jmb.2019.10.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/14/2019] [Accepted: 10/20/2019] [Indexed: 12/29/2022]
Abstract
Selective autophagy of mitochondria, or mitophagy, refers to the specific removal and degradation of damaged or surplus mitochondria via targeting to the lysosome for destruction. Disruptions in this homeostatic process may contribute to disease. The identification of diverse mitophagic pathways and how selectivity for each of these pathways is conferred is just beginning to be understood. The removal of both damaged and healthy mitochondria under disease and physiological conditions is controlled by either ubiquitin-dependent or receptor-dependent mechanisms. In this review, we will discuss the known types of mitophagy observed in mammals, recent findings related to PINK1/Parkin-mediated mitophagy (which is the most well-studied form of mitophagy), the implications of defective mitophagy to neurodegenerative processes, and unanswered questions inspiring future research that would enhance our understanding of mitochondrial quality control.
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Affiliation(s)
- Lauren E Fritsch
- Translational Biology, Medicine, and Health Graduate Program, Virginia Polytechnic Institute and State University, Roanoke, VA 24016, USA
| | - M Elyse Moore
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Shireen A Sarraf
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alicia M Pickrell
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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6
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Acaz-Fonseca E, Ortiz-Rodriguez A, Garcia-Segura LM, Astiz M. Sex differences and gonadal hormone regulation of brain cardiolipin, a key mitochondrial phospholipid. J Neuroendocrinol 2020; 32:e12774. [PMID: 31323169 DOI: 10.1111/jne.12774] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/14/2019] [Accepted: 07/15/2019] [Indexed: 12/14/2022]
Abstract
Cardiolipin (CL) is a phospholipid that is almost exclusively located in the inner mitochondrial membrane of eukaryotic cells. As a result of its unique structure and distribution, CL establishes non-covalent bonds with a long list of proteins involved in ATP production, mitochondria biogenesis, mitophagy and apoptosis. Thus, the amount of CL, as well as its fatty acid composition and location, strongly impacts upon mitochondrial-dependent functions and therefore the metabolic homeostasis of different tissues. The brain is particularly sensitive to mitochondrial dysfunction as a result of its high metabolic demand. Several mitochondrial related-neurodegenerative disorders, as well as physiological ageing, show altered CL metabolism. Furthermore, mice lacking enzymes involved in CL synthesis show cognitive impairments. CL content and metabolism are regulated by gonadal hormones in the developing and adult brain. In neuronal cultures, oestradiol increases CL content, whereas adult ovariectomy decreases CL content and alters CL metabolism in the hippocampal mitochondria. Transient sex differences in brain CL metabolism have been detected during development. At birth, brain CL has a higher proportion of unsaturated fatty acids in the brain of male mice than in the brain of females. In addition, the expression of enzymes involved in CL de novo and recycling synthetic pathways is higher in males. Most of these sex differences are abolished by the neonatal androgenisation of females, suggesting a role for testosterone in the generation of sex differences in brain CL. The regulation of brain CL by gonadal hormones may be linked to their homeostatic and protective actions in neural cells, as well as the manifestation of sex differences in neurodegenerative disorders.
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Affiliation(s)
- Estefania Acaz-Fonseca
- Instituto Cajal-CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Luis Miguel Garcia-Segura
- Instituto Cajal-CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Mariana Astiz
- Institute of Neurobiology, Center of Brain Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
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7
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Guaragnella N, Coyne LP, Chen XJ, Giannattasio S. Mitochondria-cytosol-nucleus crosstalk: learning from Saccharomyces cerevisiae. FEMS Yeast Res 2019; 18:5066171. [PMID: 30165482 DOI: 10.1093/femsyr/foy088] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/02/2018] [Indexed: 12/16/2022] Open
Abstract
Mitochondria are key cell organelles with a prominent role in both energetic metabolism and the maintenance of cellular homeostasis. Since mitochondria harbor their own genome, which encodes a limited number of proteins critical for oxidative phosphorylation and protein translation, their function and biogenesis strictly depend upon nuclear control. The yeast Saccharomyces cerevisiae has been a unique model for understanding mitochondrial DNA organization and inheritance as well as for deciphering the process of assembly of mitochondrial components. In the last three decades, yeast also provided a powerful tool for unveiling the communication network that coordinates the functions of the nucleus, the cytosol and mitochondria. This crosstalk regulates how cells respond to extra- and intracellular changes either to maintain cellular homeostasis or to activate cell death. This review is focused on the key pathways that mediate nucleus-cytosol-mitochondria communications through both transcriptional regulation and proteostatic signaling. We aim to highlight yeast that likely continues to serve as a productive model organism for mitochondrial research in the years to come.
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Affiliation(s)
- Nicoletta Guaragnella
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, CNR, Via Amendola 165/A, 70126 Bari, Italy
| | - Liam P Coyne
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA
| | - Xin Jie Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA
| | - Sergio Giannattasio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, CNR, Via Amendola 165/A, 70126 Bari, Italy
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8
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Aufschnaiter A, Büttner S. The vacuolar shapes of ageing: From function to morphology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:957-970. [PMID: 30796938 DOI: 10.1016/j.bbamcr.2019.02.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 12/21/2022]
Abstract
Cellular ageing results in accumulating damage to various macromolecules and the progressive decline of organelle function. Yeast vacuoles as well as their counterpart in higher eukaryotes, the lysosomes, emerge as central organelles in lifespan determination. These acidic organelles integrate enzymatic breakdown and recycling of cellular waste with nutrient sensing, storage, signalling and mobilization. Establishing physical contact with virtually all other organelles, vacuoles serve as hubs of cellular homeostasis. Studies in Saccharomyces cerevisiae contributed substantially to our understanding of the ageing process per se and the multifaceted roles of vacuoles/lysosomes in the maintenance of cellular fitness with progressing age. Here, we discuss the multiple roles of the vacuole during ageing, ranging from vacuolar dynamics and acidification as determinants of lifespan to the function of this organelle as waste bin, recycling facility, nutrient reservoir and integrator of nutrient signalling.
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Affiliation(s)
- Andreas Aufschnaiter
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91 Stockholm, Sweden.
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9
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Lou W, Reynolds CA, Li Y, Liu J, Hüttemann M, Schlame M, Stevenson D, Strathdee D, Greenberg ML. Loss of tafazzin results in decreased myoblast differentiation in C2C12 cells: A myoblast model of Barth syndrome and cardiolipin deficiency. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:857-865. [PMID: 29694924 DOI: 10.1016/j.bbalip.2018.04.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 12/25/2022]
Abstract
Barth syndrome (BTHS) is an X-linked genetic disorder resulting from mutations in the tafazzin gene (TAZ), which encodes the transacylase that remodels the mitochondrial phospholipid cardiolipin (CL). While most BTHS patients exhibit pronounced skeletal myopathy, the mechanisms linking defective CL remodeling and skeletal myopathy have not been determined. In this study, we constructed a CRISPR-generated stable tafazzin knockout (TAZ-KO) C2C12 myoblast cell line. TAZ-KO cells exhibit mitochondrial deficits consistent with other models of BTHS, including accumulation of monolyso-CL (MLCL), decreased mitochondrial respiration, and increased mitochondrial ROS production. Additionally, tafazzin deficiency was associated with impairment of myocyte differentiation. Future studies should determine whether alterations in myogenic determination contribute to the skeletal myopathy observed in BTHS patients. The BTHS myoblast model will enable studies to elucidate mechanisms by which defective CL remodeling interferes with normal myocyte differentiation and skeletal muscle ontogenesis.
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Affiliation(s)
- Wenjia Lou
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | | | - Yiran Li
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Jenney Liu
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Michael Schlame
- Department of Anesthesiology and Cell Biology, New York University School of Medicine, New York, NY, USA
| | - David Stevenson
- Transgenic Technology Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Glasgow, United Kingdom
| | - Douglas Strathdee
- Transgenic Technology Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Glasgow, United Kingdom
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA.
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10
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Mejia EM, Zegallai H, Bouchard ED, Banerji V, Ravandi A, Hatch GM. Expression of human monolysocardiolipin acyltransferase-1 improves mitochondrial function in Barth syndrome lymphoblasts. J Biol Chem 2018; 293:7564-7577. [PMID: 29563154 DOI: 10.1074/jbc.ra117.001024] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 03/01/2018] [Indexed: 12/12/2022] Open
Abstract
The mitochondrial polyglycerophospholipid cardiolipin (CL) is remodeled to obtain specific fatty acyl chains. This is predominantly accomplished by the transacylase enzyme tafazzin (TAZ). Barth syndrome (BTHS) patients with TAZ gene mutations exhibit impaired TAZ activity and loss in mitochondrial respiratory function. Previous studies identified monolysocardiolipin acyltransferase-1 (MLCL AT-1) as a mitochondrial enzyme capable of remodeling CL with fatty acid. In this study, we analyzed what relationship, if any, exists between TAZ and MLCL AT-1 with regard to CL remodeling and whether transfection of BTHS lymphoblasts with an MLCL AT-1 expression construct improves mitochondrial respiratory function. In healthy lymphoblasts, reduction in TAZ expression through TAZ RNAi transfection resulted in a compensatory increase in MLCL AT-1 mRNA, protein, and enzyme activity, but CL mass was unaltered. In contrast, BTHS lymphoblasts exhibited decreased TAZ gene and protein expression but in addition decreased MLCL AT-1 expression and CL mass. Transfection of BTHS lymphoblasts with MLCL AT-1 expression construct increased CL, improved mitochondrial basal respiration and protein leak, and decreased the proportion of cells producing superoxide but did not restore CL molecular species composition to control levels. In addition, BTHS lymphoblasts exhibited higher rates of glycolysis compared with healthy controls to compensate for reduced mitochondrial respiratory function. Mitochondrial supercomplex assembly was significantly impaired in BTHS lymphoblasts, and transfection of BTHS lymphoblasts with MLCL AT-1 expression construct did not restore supercomplex assembly. The results suggest that expression of MLCL AT-1 depends on functional TAZ in healthy cells. In addition, transfection of BTHS lymphoblasts with an MLCL AT-1 expression construct compensates, but not completely, for loss of mitochondrial respiratory function.
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Affiliation(s)
- Edgard M Mejia
- From the Department of Pharmacology and Therapeutics and.,Center for Research and Treatment of Atherosclerosis, University of Manitoba, Winnipeg, Manitoba R3E 0T6, Canada
| | - Hana Zegallai
- From the Department of Pharmacology and Therapeutics and
| | - Eric D Bouchard
- Research Institute in Oncology and Hematology, Cancer Care Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
| | - Versha Banerji
- Research Institute in Oncology and Hematology, Cancer Care Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
| | - Amir Ravandi
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Center, Winnipeg, Manitoba R2H 2A6, Canada, and
| | - Grant M Hatch
- From the Department of Pharmacology and Therapeutics and .,Center for Research and Treatment of Atherosclerosis, University of Manitoba, Winnipeg, Manitoba R3E 0T6, Canada.,Diabetes Research Envisioned and Accomplished in Manitoba (DREAM), Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada
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11
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Todkar K, Ilamathi HS, Germain M. Mitochondria and Lysosomes: Discovering Bonds. Front Cell Dev Biol 2017; 5:106. [PMID: 29270406 PMCID: PMC5725469 DOI: 10.3389/fcell.2017.00106] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/22/2017] [Indexed: 01/30/2023] Open
Abstract
In the last decade, the traditional view of lysosomes has been challenged by the recognition that lysosomes are not only degradative organelles, but also metabolic sensors that play a key role in the regulation of metabolism and cell growth. Similarly, mitochondria are now seen as crucial metabolic hubs dictating cell fate decisions, not just ATP-producing machines. Importantly, these functions are generally performed as a coordinate response of distinct organelles that are physically and functionally connected. While the association between mitochondria and the endoplasmic reticulum is well known, a similar interaction between mitochondria and lysosomes is now emerging. This interaction could be required to shuttle amino acids, lipids and ions such as Ca2+ between the two organelles, thereby modulating their metabolic functions. In addition, a tethering complex linking the two organelles has recently been described in yeast, although the mammalian counterpart has yet to be identified. Here, we discuss the implications of these recent findings.
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Affiliation(s)
- Kiran Todkar
- Groupe de Recherche en Signalisation Cellulaire and Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,Centre de Recherche Biomed, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Hema S Ilamathi
- Groupe de Recherche en Signalisation Cellulaire and Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,Centre de Recherche Biomed, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Marc Germain
- Groupe de Recherche en Signalisation Cellulaire and Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,Centre de Recherche Biomed, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
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12
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Soto-Heredero G, Baixauli F, Mittelbrunn M. Interorganelle Communication between Mitochondria and the Endolysosomal System. Front Cell Dev Biol 2017; 5:95. [PMID: 29164114 PMCID: PMC5681906 DOI: 10.3389/fcell.2017.00095] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/23/2017] [Indexed: 01/08/2023] Open
Abstract
The function of mitochondria and lysosomes has classically been studied separately. However, evidence has now emerged of intense crosstalk between these two organelles, such that the activity or stress status of one organelle may affect the other. Direct physical contacts between mitochondria and the endolysosomal compartment have been reported as a rapid means of interorganelle communication, mediating lipid or other metabolite exchange. Moreover, mitochondrial derived vesicles can traffic obsolete mitochondrial proteins into the endolysosomal system for their degradation or secretion to the extracellular milieu as exosomes, representing an additional mitochondrial quality control mechanism that connects mitochondria and lysosomes independently of autophagosome formation. Here, we present what is currently known about the functional and physical communication between mitochondria and lysosomes or lysosome-related organelles, and their role in sustaining cellular homeostasis.
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Affiliation(s)
| | - Francesc Baixauli
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - María Mittelbrunn
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.,Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain
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13
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Rios-Anjos RM, Camandona VDL, Bleicher L, Ferreira-Junior JR. Structural and functional mapping of Rtg2p determinants involved in retrograde signaling and aging of Saccharomyces cerevisiae. PLoS One 2017; 12:e0177090. [PMID: 28472157 PMCID: PMC5417653 DOI: 10.1371/journal.pone.0177090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 04/21/2017] [Indexed: 01/27/2023] Open
Abstract
In Saccharomyces cerevisiae mitochondrial dysfunction induces retrograde signaling, a pathway of communication from mitochondria to the nucleus that promotes a metabolic remodeling to ensure sufficient biosynthetic precursors for replication. Rtg2p is a positive modulator of this pathway that is also required for cellular longevity. This protein belongs to the ASKHA superfamily, and contains a putative N-terminal ATP-binding domain, but there is no detailed structural and functional map of the residues in this domain that accounts for their contribution to retrograde signaling and aging. Here we use Decomposition of Residue Correlation Networks and site-directed mutagenesis to identify Rtg2p structural determinants of retrograde signaling and longevity. We found that most of the residues involved in retrograde signaling surround the ATP-binding loops, and that Rtg2p N-terminus is divided in three regions whose mutants have different aging phenotypes. We also identified E137, D158 and S163 as possible residues involved in stabilization of ATP at the active site. The mutants shown here may be used to map other Rtg2p activities that crosstalk to other pathways of the cell related to genomic stability and aging.
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Affiliation(s)
| | | | - Lucas Bleicher
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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14
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Yadav PK, Rajasekharan R. Cardiolipin deficiency causes triacylglycerol accumulation in Saccharomyces cerevisiae. Mol Cell Biochem 2017; 434:89-103. [PMID: 28432553 DOI: 10.1007/s11010-017-3039-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/12/2017] [Indexed: 01/05/2023]
Abstract
In yeast, the synthesis of cardiolipin (CL) and phosphatidylethanolamine (PE) occurs mainly in mitochondria. CL and PE have overlapping functions, and they are required for mitochondrial function. PE is physiologically linked with triacylglycerol (TAG) metabolism in Saccharomyces cerevisiae, involving an acyl-CoA-independent pathway through the phospholipid:diacylglycerol acyltransferase activity of the Lro1 protein. There is no report on the physiological link between CL and TAG metabolism. Here we report a metabolic link between CL and TAG accumulation in the S. cerevisiae. Our data indicated that CL deficiency causes TAG accumulation, involving an acyl-CoA-dependent pathway through the diacylglycerol acyltransferase activity of the Dga1 protein with no changes in the TAG molecular species. The DGA1 gene deletion from the CL-deficient strains reduced the TAG levels. Data from in vitro and in vivo analyses showed that CL did not affect the enzymatic activity of Dga1. Our data also showed that CL deficiency leads to the up-regulation of acetyl-CoA synthetase genes (ACS1 and ACS2) of the cytosolic pyruvate dehydrogenase bypass pathway. This study establishes a physiological link between CL and TAG metabolism in S. cerevisiae.
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Affiliation(s)
- Pradeep Kumar Yadav
- Lipidomic Centre, Department of Lipid Science, CSIR-Central Food Technological Research Institute (CFTRI), Council of Scientific and Industrial Research, Mysore, Karnataka, 570020, India
- Academy of Scientific & Innovative Research, CSIR-CFTRI, Mysore, India
| | - Ram Rajasekharan
- Lipidomic Centre, Department of Lipid Science, CSIR-Central Food Technological Research Institute (CFTRI), Council of Scientific and Industrial Research, Mysore, Karnataka, 570020, India.
- Academy of Scientific & Innovative Research, CSIR-CFTRI, Mysore, India.
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15
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Eisenberg-Bord M, Schuldiner M. Mitochatting - If only we could be a fly on the cell wall. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1469-1480. [PMID: 28433686 DOI: 10.1016/j.bbamcr.2017.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 04/12/2017] [Accepted: 04/18/2017] [Indexed: 12/24/2022]
Abstract
Mitochondria, cellular metabolic hubs, perform many essential processes and are required for the production of metabolites such as ATP, iron-sulfur clusters, heme, amino acids and nucleotides. To fulfill their multiple roles, mitochondria must communicate with all other organelles to exchange small molecules, ions and lipids. Since mitochondria are largely excluded from vesicular trafficking routes, they heavily rely on membrane contact sites. Contact sites are areas of close proximity between organelles that allow efficient transfer of molecules, saving the need for slow and untargeted diffusion through the cytosol. More globally, multiple metabolic pathways require coordination between mitochondria and additional organelles and mitochondrial activity affects all other cellular entities and vice versa. Therefore, uncovering the different means of mitochondrial communication will allow us a better understanding of mitochondria and may illuminate disease processes that occur in the absence of proper cross-talk. In this review we focus on how mitochondria interact with all other organelles and emphasize how this communication is essential for mitochondrial and cellular homeostasis. This article is part of a Special Issue entitled: Membrane Contact Sites edited by Christian Ungermann and Benoit Kornmann.
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Affiliation(s)
- Michal Eisenberg-Bord
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001 Rehovot, Israel.
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16
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Tyurina YY, Lou W, Qu F, Tyurin VA, Mohammadyani D, Liu J, Hüttemann M, Frasso MA, Wipf P, Bayir H, Greenberg ML, Kagan VE. Lipidomics Characterization of Biosynthetic and Remodeling Pathways of Cardiolipins in Genetically and Nutritionally Manipulated Yeast Cells. ACS Chem Biol 2017; 12:265-281. [PMID: 27982579 PMCID: PMC5578713 DOI: 10.1021/acschembio.6b00995] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cardioipins (CLs) are unique tetra-acylated phospholipids of mitochondria and define the bioenergetics and regulatory functions of these organelles. An unresolved paradox is the high uniformity of CL molecular species (tetra-linoleoyl-CL) in the heart, liver, and skeletal muscles-in contrast to their high diversification in the brain. Here, we combined liquid chromatography-mass-spectrometry-based phospholipidomics with genetic and nutritional manipulations to explore CLs' biosynthetic vs postsynthetic remodeling processes in S. cerevisiae yeast cells. By applying the differential phospholipidomics analysis, we evaluated the contribution of Cld1 (CL-specific phospholipase A) and Taz1 (acyl-transferase) as the major regulatory mechanisms of the remodeling process. We further established that nutritional "pressure" by high levels of free fatty acids triggered a massive synthesis of homoacylated molecular species in all classes of phospholipids, resulting in the preponderance of the respective homoacylated CLs. We found that changes in molecular speciation of CLs induced by exogenous C18-fatty acids (C18:1 and C18:2) in wild-type (wt) cells did not occur in any of the remodeling mutant cells, including cld1Δ, taz1Δ, and cld1Δtaz1Δ. Interestingly, molecular speciation of CLs in wt and double mutant cells cld1Δtaz1Δ was markedly different. Given that the bioenergetics functions are preserved in the double mutant, this suggests that the accumulated MLCL-rather than the changed CL speciation-are the likely major contributors to the mitochondrial dysfunction in taz1Δ mutant cells (also characteristic of Barth syndrome). Biochemical studies of Cld1 specificity and computer modeling confirmed the hydrolytic selectivity of the enzyme toward C16-CL substrates and the preservation of C18:1-containing CL species.
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Affiliation(s)
- Yulia Y. Tyurina
- Department of Environmental Health and Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Wenjia Lou
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States
| | - Feng Qu
- Department of Environmental Health and Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Vladimir A Tyurin
- Department of Environmental Health and Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Dariush Mohammadyani
- Department of Environmental Health and Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States
| | - Jenney Liu
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States
| | - Michael A. Frasso
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Hülya Bayir
- Department of Environmental Health and Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Miriam. L. Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States
| | - Valerian E. Kagan
- Department of Environmental Health and Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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17
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Shen Z, Li Y, Gasparski AN, Abeliovich H, Greenberg ML. Cardiolipin Regulates Mitophagy through the Protein Kinase C Pathway. J Biol Chem 2017; 292:2916-2923. [PMID: 28062576 DOI: 10.1074/jbc.m116.753574] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 12/27/2016] [Indexed: 11/06/2022] Open
Abstract
Cardiolipin (CL), the signature phospholipid of mitochondrial membranes, is important for cardiovascular health, and perturbation of CL metabolism is implicated in cardiovascular disease. Although the role of CL in mitochondrial function, biogenesis, and genome stability has been studied, recent findings indicate that it is essential for functions apart from mitochondrial bioenergetics. In this study, we report that mitophagy is perturbed in CL-deficient yeast cells. Mutants of autophagy/mitophagy genes ATG8, ATG18, and ATG32 synthetically interact with CL synthase mutant crd1Δ. CL-deficient cells exhibited decreased GFP-tagged mitochondrial proteins inside the vacuole and decreased free GFP, consistent with decreased mitophagy. Both PKC and high osmolarity glycerol (HOG) MAPK pathways were shown previously to be required for mitophagy. Activation of both MAPKs was defective in CL-deficient cells. Deletion of HOG pathway genes SHO1, SSK1, STE50, and HOG1 exacerbated crd1Δ growth. 1 m sorbitol and 0.2 m NaCl, which induce the HOG pathway, rescued growth of the mutant. Activation of the MAPK Slt2p was defective in crd1Δ cells, and up-regulation of the PKC pathway by expression of the PKC1R398P gene, which encodes constitutively activated Pkc1p, rescued crd1Δ growth and mitophagy defects. These findings indicate that loss of CL impairs MAPK pathway activation, and decreased activation of the PKC pathway leads to defective mitophagy.
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Affiliation(s)
- Zheni Shen
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
| | - Yiran Li
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
| | - Alexander N Gasparski
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
| | - Hagai Abeliovich
- the Institute of Biochemistry, Food Science and Nutrition, Hebrew University of Jerusalem, 76100 Rehovot, Israel
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
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18
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Regulation of autophagy by mitochondrial phospholipids in health and diseases. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:114-129. [PMID: 27502688 DOI: 10.1016/j.bbalip.2016.08.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/28/2016] [Accepted: 08/04/2016] [Indexed: 12/16/2022]
Abstract
Autophagy is an evolutionarily conserved mechanism that maintains nutrient homeostasis by degrading protein aggregates and damaged organelles. Autophagy is reduced in aging, which is implicated in the pathogenesis of aging-related diseases, including cancers, obesity, type 2 diabetes, cardiovascular diseases, and neurodegenerative diseases. Mitochondria-derived phospholipids cardiolipin, phosphatidylethanolamine, and phosphatidylglycerol are critical throughout the autophagic process, from initiation and phagophore formation to elongation and fusion with endolysosomal vesicles. Cardiolipin is also required for mitochondrial fusion and fission, an important step in isolating dysfunctional mitochondria for mitophagy. Furthermore, genetic screen in yeast has identified a surprising role for cardiolipin in regulating lysosomal function. Phosphatidylethanolamine plays a pivotal role in supporting the autophagic process, including autophagosome elongation as part of lipidated Atg8/LC3. An emerging role for phosphatidylglycerol in AMPK and mTORC1 signaling as well as mitochondrial fission may provide the first glimpse into the function of phosphatidylglycerol apart from being a precursor for cardiolipin. This review examines the effects of manipulating phospholipids on autophagy and mitophagy in health and diseases, as well as current limitations in the field. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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19
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Dimmer KS, Rapaport D. Mitochondrial contact sites as platforms for phospholipid exchange. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:69-80. [PMID: 27477677 DOI: 10.1016/j.bbalip.2016.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 12/15/2022]
Abstract
Mitochondria are unique organelles that contain their own - although strongly reduced - genome, and are surrounded by two membranes. While most cellular phospholipid biosynthesis takes place in the ER, mitochondria harbor the whole spectrum of glycerophospholipids common to biological membranes. Mitochondria also contribute to overall phospholipid biosynthesis in cells by producing phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Considering these features, it is not surprising that mitochondria maintain highly active exchange of phospholipids with other cellular compartments. In this contribution we describe the transport of phospholipids between mitochondria and other organelles, and discuss recent developments in our understanding of the molecular functions of the protein complexes that mediate these processes. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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Affiliation(s)
- Kai Stefan Dimmer
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
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20
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Hsu P, Liu X, Zhang J, Wang HG, Ye JM, Shi Y. Cardiolipin remodeling by TAZ/tafazzin is selectively required for the initiation of mitophagy. Autophagy 2016; 11:643-52. [PMID: 25919711 DOI: 10.1080/15548627.2015.1023984] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Tafazzin (TAZ) is a phospholipid transacylase that catalyzes the remodeling of cardiolipin, a mitochondrial phospholipid required for oxidative phosphorylation. Mutations of TAZ cause Barth syndrome, which is characterized by mitochondrial dysfunction and dilated cardiomyopathy, leading to premature death. However, the molecular mechanisms underlying the cause of mitochondrial dysfunction in Barth syndrome remain poorly understood. Here we investigated the role of TAZ in regulating mitochondrial function and mitophagy. Using primary mouse embryonic fibroblasts (MEFs) with doxycycline-inducible knockdown of Taz, we showed that TAZ deficiency in MEFs caused defective mitophagosome biogenesis, but not other autophagic processes. Consistent with a key role of mitophagy in mitochondria quality control, TAZ deficiency in MEFs also led to impaired oxidative phosphorylation and severe oxidative stress. Together, these findings provide key insights on mitochondrial dysfunction in Barth syndrome, suggesting that pharmacological restoration of mitophagy may provide a novel treatment for this lethal condition.
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Key Words
- AdGFP-LC3, recombinant adenovirus expressing GFP tagged MAP1LC3B
- AdTAZ, recombinant adenovirus expressing Myc-tagged TAZ
- BTHS, Barth syndrome
- BafA1, bafilomycin A1
- Barth syndrome
- CCCP, carbonyl cyanide m-chlorophenylhydrazone
- CL, cardiolipin
- Dox, doxycycline
- FCCP, carbonyl cyanide p-triflouromethoxyphenylhydrazone
- LTG, LysoTracker Green
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 beta
- MEF, mouse embryonic fibroblast
- MLCL, monolysocardiolipin
- MTR, MitoTracker Red
- PARK2, parkin RBR E3 ubiquitin protein ligase
- PINK1, PTEN-induced putative kinase 1
- SOD2, superoxide dismutase 2 mitochondrial
- TAZ, tafazzin
- TLCL, tetralinoleoyl-cardiolipin
- autophagy
- cardiolipin
- mitochondrial dysfunction
- mitophagosome
- mitophagy
- tafazzin
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Affiliation(s)
- Paul Hsu
- a Department of Cellular and Molecular Physiology ; Hershey , PA USA
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21
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Luévano-Martínez LA, Kowaltowski AJ. Phosphatidylglycerol-derived phospholipids have a universal, domain-crossing role in stress responses. Arch Biochem Biophys 2015; 585:90-97. [PMID: 26391924 DOI: 10.1016/j.abb.2015.09.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 11/19/2022]
Abstract
Phosphatidylglycerol and phospholipids derived from it are widely distributed throughout the three domains of life. Cardiolipin is the best characterized of these phospholipids, and plays a key role in the response to environmental variations. Phosphatidylglycerol-derived phospholipids confer cell membranes with a wide range of responses, including changes in surface charge, fluidity, flexibility, morphology, biosynthesis and remodeling, that adapt the cell to these situations. Furthermore, the synthesis and remodeling of these phospholipids is finely regulated, highlighting the importance of these lipids in cell homeostasis and responses during stressful situations. In this article, we review the most important roles of these anionic phospholipids across domains, focusing on the biophysical basis by which these phospholipids are used in stress responses.
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Affiliation(s)
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, SP, Brazil.
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22
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The Role of Cardiolipin in Cardiovascular Health. BIOMED RESEARCH INTERNATIONAL 2015; 2015:891707. [PMID: 26301254 PMCID: PMC4537736 DOI: 10.1155/2015/891707] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/08/2015] [Indexed: 12/20/2022]
Abstract
Cardiolipin (CL), the signature phospholipid of mitochondrial membranes, is crucial for both mitochondrial function and cellular processes outside of the mitochondria. The importance of CL in cardiovascular health is underscored by the life-threatening genetic disorder Barth syndrome (BTHS), which manifests clinically as cardiomyopathy, skeletal myopathy, neutropenia, and growth retardation. BTHS is caused by mutations in the gene encoding tafazzin, the transacylase that carries out the second CL remodeling step. In addition to BTHS, CL is linked to other cardiovascular diseases (CVDs), including cardiomyopathy, atherosclerosis, myocardial ischemia-reperfusion injury, heart failure, and Tangier disease. The link between CL and CVD may possibly be explained by the physiological roles of CL in pathways that are cardioprotective, including mitochondrial bioenergetics, autophagy/mitophagy, and mitogen activated protein kinase (MAPK) pathways. In this review, we focus on the role of CL in the pathogenesis of CVD as well as the molecular mechanisms that may link CL functions to cardiovascular health.
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23
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Ungermann C. vCLAMPs—an intimate link between vacuoles and mitochondria. Curr Opin Cell Biol 2015; 35:30-6. [DOI: 10.1016/j.ceb.2015.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/20/2015] [Accepted: 03/26/2015] [Indexed: 11/26/2022]
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Genome-Wide Screens in Saccharomyces cerevisiae Highlight a Role for Cardiolipin in Biogenesis of Mitochondrial Outer Membrane Multispan Proteins. Mol Cell Biol 2015; 35:3200-11. [PMID: 26149385 DOI: 10.1128/mcb.00107-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/26/2015] [Indexed: 11/20/2022] Open
Abstract
A special group of mitochondrial outer membrane (MOM) proteins spans the membrane several times via multiple helical segments. Such multispan proteins are synthesized on cytosolic ribosomes before their targeting to mitochondria and insertion into the MOM. Previous work recognized the import receptor Tom70 and the mitochondrial import (MIM) complex, both residents of the MOM, as required for optimal biogenesis of these proteins. However, their involvement is not sufficient to explain either the entire import pathway or its regulation. To identify additional factors that are involved in the biogenesis of MOM multispan proteins, we performed complementary high-throughput visual and growth screens in Saccharomyces cerevisiae. Cardiolipin (CL) synthase (Crd1) appeared as a candidate in both screens. Our results indeed demonstrate lower steady-state levels of the multispan proteins Ugo1, Scm4, and Om14 in mitochondria from crd1Δ cells. Importantly, MOM single-span proteins were not affected by this mutation. Furthermore, organelles lacking Crd1 had a lower in vitro capacity to import newly synthesized Ugo1 and Scm4 molecules. Crd1, which is located in the mitochondrial inner membrane, condenses phosphatidylglycerol together with CDP-diacylglycerol to obtain de novo synthesized CL molecules. Hence, our findings suggest that CL is an important component in the biogenesis of MOM multispan proteins.
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25
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Wang L, Liu X, Nie J, Zhang J, Kimball SR, Zhang H, Zhang WJ, Jefferson LS, Cheng Z, Ji Q, Shi Y. ALCAT1 controls mitochondrial etiology of fatty liver diseases, linking defective mitophagy to steatosis. Hepatology 2015; 61:486-96. [PMID: 25203315 PMCID: PMC4303512 DOI: 10.1002/hep.27420] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 08/30/2014] [Indexed: 12/23/2022]
Abstract
UNLABELLED Defective autophagy is implicated in the pathogenesis of nonalcoholic fatty liver diseases (NAFLD) through poorly defined mechanisms. Cardiolipin is a mitochondrial phospholipid required for bioenergetics and mitophagy from yeast to mammals. Here we investigated a role for ALCAT1 in the development of NAFLD. ALCAT1 is a lysocardiolipin acyltransferase that catalyzes pathological cardiolipin remodeling in several aging-related diseases. We show that the onset of diet-induced NAFLD caused autophagic arrest in hepatocytes, leading to oxidative stress, mitochondrial dysfunction, and insulin resistance. In contrast, targeted deletion of ALCAT1 in mice prevented the onset of NAFLD. ALCAT1 deficiency also restored mitophagy, mitochondrial architecture, mitochondrial DNA (mtDNA) fidelity, and oxidative phosphorylation. In support of a causative role of the enzyme in a mitochondrial etiology of the disease, hepatic ALCAT1 expression was significantly up-regulated in mouse models of NAFLD. CONCLUSION Forced expression of ALCAT1 in primary hepatocytes led to multiple defects that are highly reminiscent of NAFLD, including steatosis, defective autophagy, and mitochondrial dysfunction, linking pathological cardiolipin remodeling by ALCAT1 to the pathogenesis of NAFLD.
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Affiliation(s)
- Li Wang
- Department of Endocrinology and Metabolism, Xijing Hospital, Fourth Military Medical University, Xi’an, China,Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033,To whom all correspondences should be addressed: Yuguang Shi, Ph.D., Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033, Tel: 717-531-0003/Fax: 717-531-7667, ,
| | - Xiaolei Liu
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033,To whom all correspondences should be addressed: Yuguang Shi, Ph.D., Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033, Tel: 717-531-0003/Fax: 717-531-7667, ,
| | - Jia Nie
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033
| | - Jun Zhang
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033
| | - Scot R. Kimball
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033
| | - Hai Zhang
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033,Department of Pathophysiology, Second Military Medical University, Shanghai 200433, China
| | - Weiping J. Zhang
- Department of Pathophysiology, Second Military Medical University, Shanghai 200433, China
| | - Leonard S. Jefferson
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033
| | - Zeneng Cheng
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 41000, China
| | - Qiuhe Ji
- Department of Endocrinology and Metabolism, Xijing Hospital, Fourth Military Medical University, Xi’an, China,To whom all correspondences should be addressed: Yuguang Shi, Ph.D., Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033, Tel: 717-531-0003/Fax: 717-531-7667, ,
| | - Yuguang Shi
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033,Department of Pathophysiology, Second Military Medical University, Shanghai 200433, China,To whom all correspondences should be addressed: Yuguang Shi, Ph.D., Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, 500 University Drive, H166, Hershey, PA 17033, Tel: 717-531-0003/Fax: 717-531-7667, ,
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26
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27
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Canonico B, Candiracci M, Citterio B, Curci R, Squarzoni S, Mazzoni A, Papa S, Piatti E. Honey flavonoids inhibit Candida albicans morphogenesis by affecting DNA behavior and mitochondrial function. Future Microbiol 2014; 9:445-56. [PMID: 24810344 DOI: 10.2217/fmb.14.17] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
AIM Candida albicans is a pathogenic yeast, which forms a range of polarized and expanded cell shapes. We aimed to determine the correlation between honey extract (HFE) activity and changes in C. albicans cell cycle, morphology and subcellular organelles. MATERIALS & METHODS HFE anticandidal properties were investigated using flow cytometry and scanning electron microscopy. RESULTS Flow cytometry and scanning electron microscopy analyses indicated that HFE may inhibit the growth of the three phenotypes displayed by C. albicans and reduce infection by affecting membrane integrity. HFE affects hyphal transition by reducing the G0/G1 phase and increasing the G2/M phase. Conversely, yeast and pseudohyphae do not appear to be affected. Modifications of vacuolization and mitochondrial activity, during yeast-hypha transition establish the involvement of vacuole and mitochondria. CONCLUSION HFE improved mitochondrial functionality and reduced the vacuolization, modifying the branching process associated with virulence. It is hypothesized that HFE induces changes in cell cycle progress, membrane integrity, mitochondrial function and biogenesis.
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Affiliation(s)
- Barbara Canonico
- Department of Earth, Life & Environmental Sciences, Urbino, Italy
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28
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Zhang J, Xu D, Nie J, Han R, Zhai Y, Shi Y. Comparative gene identification-58 (CGI-58) promotes autophagy as a putative lysophosphatidylglycerol acyltransferase. J Biol Chem 2014; 289:33044-53. [PMID: 25315780 DOI: 10.1074/jbc.m114.573857] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
CGI-58 is a lipid droplet-associated protein that, when mutated, causes Chanarin-Dorfman syndrome in humans, which is characterized by excessive storage of triglyceride in various tissues. However, the molecular mechanisms underlying the defect remain elusive. CGI-58 was previously reported to catalyze the resynthesis of phosphatidic acid as a lysophosphatidic acid acyltransferase. In addition to triglyceride, phosphatidic acid is also used a substrate for the synthesis of various mitochondrial phospholipids. In this report, we investigated the propensity of CGI-58 in the remodeling of various phospholipids. We found that the recombinant CGI-58 overexpressed in mammalian cells or purified from Sf9 insect cells catalyzed efficiently the reacylation of lysophosphatidylglycerol to phosphatidylglycerol (PG), which requires acyl-CoA as the acyl donor. In contrast, the recombinant CGI-58 was devoid of acyltransferase activity toward other lysophospholipids. Accordingly, overexpression and knockdown of CGI-58 adversely affected the endogenous PG level in C2C12 cells. PG is a substrate for the synthesis of cardiolipin, which is required for mitochondrial oxidative phosphorylation and mitophagy. Consequently, overexpression and knockdown of CGI-58 adversely affected autophagy and mitophagy in C2C12 cells. In support for a key role of CGI-58 in mitophagy, overexpression of CGI-58 significantly stimulated mitochondrial fission and translocation of PINK1 to mitochondria, key steps involved in mitophagy. Furthermore, overexpression of CGI-58 promoted mitophagic initiation through activation of 5'-AMP-activated protein kinase and inhibition of mTORC1 mammalian target of rapamycin complex 1 signaling, the positive and negative regulators of autophagy, respectively. Together, these findings identified novel molecular mechanisms by which CGI-58 regulates lipid homeostasis, because defective autophagy is implicated in dyslipidemia and fatty liver diseases.
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Affiliation(s)
- Jun Zhang
- the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 From the Beijing Key Laboratory of Gene Resource and Molecular Development and College of Life Sciences, Beijing Normal University, Beijing 100875, China and
| | - Dan Xu
- the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Jia Nie
- the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Ruili Han
- the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Yonggong Zhai
- From the Beijing Key Laboratory of Gene Resource and Molecular Development and College of Life Sciences, Beijing Normal University, Beijing 100875, China and
| | - Yuguang Shi
- the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
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Hönscher C, Mari M, Auffarth K, Bohnert M, Griffith J, Geerts W, van der Laan M, Cabrera M, Reggiori F, Ungermann C. Cellular Metabolism Regulates Contact Sites between Vacuoles and Mitochondria. Dev Cell 2014; 30:86-94. [DOI: 10.1016/j.devcel.2014.06.006] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 04/04/2014] [Accepted: 06/09/2014] [Indexed: 11/25/2022]
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30
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Yucel EB, Eraslan S, Ulgen KO. The impact of medium acidity on the chronological life span ofSaccharomyces cerevisiae - lipids, signaling cascades, mitochondrial and vacuolar functions. FEBS J 2014; 281:1281-303. [DOI: 10.1111/febs.12705] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Esra B. Yucel
- Department of Chemical Engineering; Boğaziçi University; Istanbul Turkey
| | - Serpil Eraslan
- Department of Chemical Engineering; Boğaziçi University; Istanbul Turkey
| | - Kutlu O. Ulgen
- Department of Chemical Engineering; Boğaziçi University; Istanbul Turkey
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31
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Raja V, Greenberg ML. The functions of cardiolipin in cellular metabolism-potential modifiers of the Barth syndrome phenotype. Chem Phys Lipids 2014; 179:49-56. [PMID: 24445246 DOI: 10.1016/j.chemphyslip.2013.12.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/20/2013] [Accepted: 12/20/2013] [Indexed: 12/30/2022]
Abstract
The phospholipid cardiolipin (CL) plays a role in many cellular functions and signaling pathways both inside and outside of mitochondria. This review focuses on the role of CL in energy metabolism. Many reactions of electron transport and oxidative phosphorylation, the transport of metabolites required for these processes, and the stabilization of electron transport chain supercomplexes require CL. Recent studies indicate that CL is required for the synthesis of iron-sulfur (Fe-S) co-factors, which are essential for numerous metabolic pathways. Activation of carnitine shuttle enzymes that are required for fatty acid metabolism is CL dependent. The presence of substantial amounts of CL in the peroxisomal membrane suggests that CL may be required for peroxisomal functions. Understanding the role of CL in energy metabolism may identify physiological modifiers that exacerbate the loss of CL and underlie the variation in symptoms observed in Barth syndrome, a genetic disorder of CL metabolism.
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Affiliation(s)
- Vaishnavi Raja
- Department of Biological Sciences, Wayne State University, Detroit, United States
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, United States.
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32
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de Paepe R, Lemaire SD, Danon A. Cardiolipin at the heart of stress response across kingdoms. PLANT SIGNALING & BEHAVIOR 2014; 9:e29228. [PMID: 25763690 PMCID: PMC4203511 DOI: 10.4161/psb.29228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Cardiolipin is a key phospholipid most specifically found in the membrane of mitochondria in yeasts, plants, and animals. Cardiolipins are essential for the maintenance, the integrity, and the dynamics of mitochondria. In most eukaryotes mitochondria play a central role in the response and adaptation to stress conditions especially through their importance in the control of programmed cell death. To assess the impact of the absence of cardiolipin, knock-down of the expression of cardiolipin synthase, the last enzyme of cardiolipin synthesis pathway in eukaryotes has been performed in yeasts, animals, and plants. These studies showed that cardiolipin is not only important for mitochondrial ultrastructure and for the stability of respiratory complexes, but it is also a key player in the response to stress, the formation of reactive oxygen species, and the execution of programmed cell death.
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Affiliation(s)
- Rosine de Paepe
- Institut de Biologie des Plantes; Saclay Plant Science; Université de Paris-Sud XI; CNRS; UMR 8618; Orsay Cedex, France
| | - Stéphane D Lemaire
- Sorbonne Universités; UPMC Univ Paris 06; UMR 8226; LBMCE; Institut de Biologie Physico-Chimique; Paris, France
- Centre National de la Recherche Scientifique; UMR 8226; LBMCE; Institut de Biologie Physico-Chimique; Paris, France
| | - Antoine Danon
- Sorbonne Universités; UPMC Univ Paris 06; UMR 8226; LBMCE; Institut de Biologie Physico-Chimique; Paris, France
- Centre National de la Recherche Scientifique; UMR 8226; LBMCE; Institut de Biologie Physico-Chimique; Paris, France
- Correspondence to: Antoine Danon,
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33
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Harner ME, Unger AK, Izawa T, Walther DM, Ozbalci C, Geimer S, Reggiori F, Brügger B, Mann M, Westermann B, Neupert W. Aim24 and MICOS modulate respiratory function, tafazzin-related cardiolipin modification and mitochondrial architecture. eLife 2014; 3:e01684. [PMID: 24714493 PMCID: PMC3975624 DOI: 10.7554/elife.01684] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Structure and function of mitochondria are intimately linked. In a search for components that participate in building the elaborate architecture of this complex organelle we have identified Aim24, an inner membrane protein. Aim24 interacts with the MICOS complex that is required for the formation of crista junctions and contact sites between inner and outer membranes. Aim24 is necessary for the integrity of the MICOS complex, for normal respiratory growth and mitochondrial ultrastructure. Modification of MICOS subunits Mic12 or Mic26 by His-tags in the absence of Aim24 leads to complete loss of cristae and respiratory complexes. In addition, the level of tafazzin, a cardiolipin transacylase, is drastically reduced and the composition of cardiolipin is modified like in mutants lacking tafazzin. In conclusion, Aim24 by interacting with the MICOS complex plays a key role in mitochondrial architecture, composition and function. DOI: http://dx.doi.org/10.7554/eLife.01684.001.
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34
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Jazwinski SM. The retrograde response: a conserved compensatory reaction to damage from within and from without. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 127:133-54. [PMID: 25149216 DOI: 10.1016/b978-0-12-394625-6.00005-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The retrograde response was discovered in Saccharomyces cerevisiae as a signaling pathway from the mitochondrion to the nucleus that triggers an array of gene regulatory changes in the latter. The activation of the retrograde response compensates for the deficits associated with aging, and thus it extends yeast replicative life span. The retrograde response is activated by the progressive decline in mitochondrial membrane potential during aging that is the result of increasing mitochondrial dysfunction. The ensuing metabolic adaptations and stress resistance can only delay the inevitable demise of the yeast cell. The retrograde response is embedded in a network of signal transduction pathways that impinge upon virtually every aspect of cell physiology. Thus, its manifestations are complicated. Many of these pathways have been implicated in life span regulation quite independently of the retrograde response. Together, they operate in a delicate balance in promoting longevity. The retrograde response is closely aligned with cell quality control, often performing when quality control is not sufficient to assure longevity. Among the key pathways related to this aspect of retrograde signaling are target of rapamycin and ceramide signaling. The retrograde response can also be found in other organisms, including Caenorhabditis elegans, Drosophila melanogaster, mouse, and human, where it exhibits an ever-increasing complexity that may be corralled by the transcription factor NFκB. The retrograde response may have evolved as a cytoprotective mechanism that senses and defends the organism from pathogens and environmental toxins.
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Affiliation(s)
- S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
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35
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Ye C, Lou W, Li Y, Chatzispyrou IA, Hüttemann M, Lee I, Houtkooper RH, Vaz FM, Chen S, Greenberg ML. Deletion of the cardiolipin-specific phospholipase Cld1 rescues growth and life span defects in the tafazzin mutant: implications for Barth syndrome. J Biol Chem 2013; 289:3114-25. [PMID: 24318983 DOI: 10.1074/jbc.m113.529487] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cardiolipin (CL) that is synthesized de novo is deacylated to monolysocardiolipin (MLCL), which is reacylated by tafazzin. Remodeled CL contains mostly unsaturated fatty acids. In eukaryotes, loss of tafazzin leads to growth and respiration defects, and in humans, this results in the life-threatening disorder Barth syndrome. Tafazzin deficiency causes a decrease in the CL/MLCL ratio and decreased unsaturated CL species. Which of these biochemical outcomes contributes to the physiological defects is not known. Yeast cells have a single CL-specific phospholipase, Cld1, that can be exploited to distinguish between these outcomes. The cld1Δ mutant has decreased unsaturated CL, but the CL/MLCL ratio is similar to that of wild type cells. We show that cld1Δ rescues growth, life span, and respiratory defects of the taz1Δ mutant. This suggests that defective growth and respiration in tafazzin-deficient cells are caused by the decreased CL/MLCL ratio and not by a deficiency in unsaturated CL. CLD1 expression is increased during respiratory growth and regulated by the heme activator protein transcriptional activation complex. Overexpression of CLD1 leads to decreased mitochondrial respiration and growth and instability of mitochondrial DNA. However, ATP concentrations are maintained by increasing glycolysis. We conclude that transcriptional regulation of Cld1-mediated deacylation of CL influences energy metabolism by modulating the relative contribution of glycolysis and respiration.
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Affiliation(s)
- Cunqi Ye
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
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36
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Eisenberg T, Büttner S. Lipids and cell death in yeast. FEMS Yeast Res 2013; 14:179-97. [PMID: 24119111 PMCID: PMC4255311 DOI: 10.1111/1567-1364.12105] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/21/2013] [Accepted: 09/25/2013] [Indexed: 01/22/2023] Open
Abstract
Understanding lipid-induced malfunction represents a major challenge of today's biomedical research. The connection of lipids to cellular and organ dysfunction, cell death, and disease (often referred to as lipotoxicity) is more complex than the sole lipotoxic effects of excess free fatty acids and requires genetically tractable model systems for mechanistic investigation. We herein summarize recent advances in the field of lipid-induced toxicity that employ the established model system for cell death and aging research of budding yeast Saccharomyces cerevisiae. Studies in yeast have shed light on various aspects of lipotoxicity, including free fatty acid toxicity, sphingolipid-modulated cell death as well as the involvement of cardiolipin and lipid peroxidation in the mitochondrial pathways of apoptosis. Regimens used range from exogenously applied lipids, genetic modulation of lipolysis and triacylglyceride synthesis, variations in sphingolipid/ceramide metabolism as well as changes in peroxisome function by either genetic or pharmacological means. In future, the yeast model of programmed cell death will further contribute to the clarification of crucial questions of lipid-associated malfunction.
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Affiliation(s)
- Tobias Eisenberg
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
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37
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Pineau B, Bourge M, Marion J, Mauve C, Gilard F, Maneta-Peyret L, Moreau P, Satiat-Jeunemaître B, Brown SC, De Paepe R, Danon A. The importance of cardiolipin synthase for mitochondrial ultrastructure, respiratory function, plant development, and stress responses in Arabidopsis. THE PLANT CELL 2013; 25:4195-208. [PMID: 24151294 PMCID: PMC3877823 DOI: 10.1105/tpc.113.118018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Cardiolipin (CL) is the signature phospholipid of the mitochondrial inner membrane. In animals and yeast (Saccharomyces cerevisiae), CL depletion affects the stability of respiratory supercomplexes and is thus crucial to the energy metabolism of obligate aerobes. In eukaryotes, the last step of CL synthesis is catalyzed by CARDIOLIPIN SYNTHASE (CLS), encoded by a single-copy gene. Here, we characterize a cls mutant in Arabidopsis thaliana, which is devoid of CL. In contrast to yeast cls, where development is little affected, Arabidopsis cls seedlings are slow developing under short-day conditions in vitro and die if they are transferred to long-day (LD) conditions. However, when transferred to soil under LD conditions under low light, cls plants can reach the flowering stage, but they are not fertile. The cls mitochondria display abnormal ultrastructure and reduced content of respiratory complex I/complex III supercomplexes. The marked accumulation of tricarboxylic acid cycle derivatives and amino acids demonstrates mitochondrial dysfunction. Mitochondrial and chloroplastic antioxidant transcripts are overexpressed in cls leaves, and cls protoplasts are more sensitive to programmed cell death effectors, UV light, and heat shock. Our results show that CLS is crucial for correct mitochondrial function and development in Arabidopsis under both optimal and stress conditions.
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Affiliation(s)
- Bernard Pineau
- Institut de Biologie des Plantes, Saclay Plant Science, Université de Paris-Sud XI, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8618, 91405 Orsay cedex, France
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38
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Guaragnella N, Ždralević M, Lattanzio P, Marzulli D, Pracheil T, Liu Z, Passarella S, Marra E, Giannattasio S. Yeast growth in raffinose results in resistance to acetic-acid induced programmed cell death mostly due to the activation of the mitochondrial retrograde pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2765-2774. [PMID: 23906793 DOI: 10.1016/j.bbamcr.2013.07.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/27/2013] [Accepted: 07/19/2013] [Indexed: 12/22/2022]
Abstract
In order to investigate whether and how a modification of mitochondrial metabolism can affect yeast sensitivity to programmed cell death (PCD) induced by acetic acid (AA-PCD), yeast cells were grown on raffinose, as a sole carbon source, which, differently from glucose, favours mitochondrial respiration. We found that, differently from glucose-grown cells, raffinose-grown cells were mostly resistant to AA-PCD and that this was due to the activation of mitochondrial retrograde (RTG) response, which increased with time, as revealed by the up-regulation of the peroxisomal isoform of citrate synthase and isocitrate dehydrogenase isoform 1, RTG pathway target genes. Accordingly, the deletion of RTG2 and RTG3, a positive regulator and a transcription factor of the RTG pathway, resulted in AA-PCD, as shown by TUNEL assay. Neither deletion in raffinose-grown cells of HAP4, encoding the positive regulatory subunit of the Hap2,3,4,5 complex nor constitutive activation of the RTG pathway in glucose-grown cells due to deletion of MKS1, a negative regulator of RTG pathway, had effect on yeast AA-PCD. The RTG pathway was found to be activated in yeast cells containing mitochondria, in which membrane potential was measured, capable to consume oxygen in a manner stimulated by the uncoupler CCCP and inhibited by the respiratory chain inhibitor antimycin A. AA-PCD resistance in raffinose-grown cells occurs with a decrease in both ROS production and cytochrome c release as compared to glucose-grown cells en route to AA-PCD.
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Affiliation(s)
| | - Maša Ždralević
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Paolo Lattanzio
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Domenico Marzulli
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Tammy Pracheil
- Department of Biological Sciences, University of New Orleans, 2000 Lakeshore Drive, New Orleans, LA 70148, USA
| | - Zhengchang Liu
- Department of Biological Sciences, University of New Orleans, 2000 Lakeshore Drive, New Orleans, LA 70148, USA
| | - Salvatore Passarella
- Dipartimento di Medicina e Scienze per la Salute, Università del Molise, Via de Sanctis, 86100 Campobasso, Italy
| | - Ersilia Marra
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Sergio Giannattasio
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy.
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39
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Tan T, Ozbalci C, Brügger B, Rapaport D, Dimmer KS. Mcp1 and Mcp2, two novel proteins involved in mitochondrial lipid homeostasis. J Cell Sci 2013; 126:3563-74. [PMID: 23781023 DOI: 10.1242/jcs.121244] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The yeast mitochondrial outer membrane (MOM) protein Mdm10 is involved in at least three different processes: (1) association of mitochondria with the endoplasmic reticulum and mitochondrial lipid homeostasis (2) membrane assembly of MOM proteins, and (3) inheritance and morphogenesis of mitochondria. To decipher the precise role of Mdm10 in mitochondrial function, we screened for high-copy suppressors of the severe growth defect of the mdm10Δ mutant. We identified two novel mitochondrial proteins (open reading frames YOR228c and YLR253w) that we named Mdm10 complementing protein (Mcp) 1 and Mcp2. Overexpression of Mcp1 or Mcp2 restores the alterations in morphology and stability of respiratory chain complexes of mitochondria devoid of Mdm10, but the observed defect in assembly of MOM proteins is not rescued. Lipid analysis demonstrates that elevated levels of Mcp1 and Mcp2 restore the alterations in mitochondrial phospholipid and ergosterol homeostasis in cells lacking Mdm10. Collectively, this work identifies two novel proteins that play a role in mitochondrial lipid homeostasis and describes a role of Mdm10 in ergosterol trafficking.
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Affiliation(s)
- Tao Tan
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
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40
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Affiliation(s)
| | - Zaza Khuchua
- Division of Molecular and Cardiovascular Biology; Cincinnati Children's Research Foundation; Cincinnati; OH; USA
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41
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Patil VA, Greenberg ML. Cardiolipin-mediated cellular signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:195-213. [PMID: 23775697 DOI: 10.1007/978-94-007-6331-9_11] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
This review focuses on recent studies showing that cardiolipin (CL), a unique mitochondrial phospholipid, regulates many cellular functions and signaling pathways, both inside and outside the mitochondria. Inside the mitochondria, CL is a critical target of mitochondrial generated reactive oxygen species (ROS) and regulates signaling events related to apoptosis and aging. CL deficiency causes perturbation of signaling pathways outside the mitochondria, including the PKC-Slt2 cell integrity pathway and the high osmolarity glycerol (HOG) pathway, and is a key player in the cross-talk between the mitochondria and the vacuole. Understanding these connections may shed light on the pathology of Barth syndrome, a disorder of CL remodeling.
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Affiliation(s)
- Vinay A Patil
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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42
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Yu D, Danku JMC, Baxter I, Kim S, Vatamaniuk OK, Vitek O, Ouzzani M, Salt DE. High-resolution genome-wide scan of genes, gene-networks and cellular systems impacting the yeast ionome. BMC Genomics 2012; 13:623. [PMID: 23151179 PMCID: PMC3652779 DOI: 10.1186/1471-2164-13-623] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/26/2012] [Indexed: 12/11/2022] Open
Abstract
Background To balance the demand for uptake of essential elements with their potential toxicity living cells have complex regulatory mechanisms. Here, we describe a genome-wide screen to identify genes that impact the elemental composition (‘ionome’) of yeast Saccharomyces cerevisiae. Using inductively coupled plasma – mass spectrometry (ICP-MS) we quantify Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, S and Zn in 11890 mutant strains, including 4940 haploid and 1127 diploid deletion strains, and 5798 over expression strains. Results We identified 1065 strains with an altered ionome, including 584 haploid and 35 diploid deletion strains, and 446 over expression strains. Disruption of protein metabolism or trafficking has the highest likelihood of causing large ionomic changes, with gene dosage also being important. Gene over expression produced more extreme ionomic changes, but over expression and loss of function phenotypes are generally not related. Ionomic clustering revealed the existence of only a small number of possible ionomic profiles suggesting fitness tradeoffs that constrain the ionome. Clustering also identified important roles for the mitochondria, vacuole and ESCRT pathway in regulation of the ionome. Network analysis identified hub genes such as PMR1 in Mn homeostasis, novel members of ionomic networks such as SMF3 in vacuolar retrieval of Mn, and cross-talk between the mitochondria and the vacuole. All yeast ionomic data can be searched and downloaded at http://www.ionomicshub.org. Conclusions Here, we demonstrate the power of high-throughput ICP-MS analysis to functionally dissect the ionome on a genome-wide scale. The information this reveals has the potential to benefit both human health and agriculture.
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Affiliation(s)
- Danni Yu
- Institute of Biological and Environmental Science, University of Aberdeen, Scotland, UK.
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43
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Short MK, Hallett JP, Tar K, Dange T, Schmidt M, Moir R, Willis IM, Jubinsky PT. The yeast magmas ortholog pam16 has an essential function in fermentative growth that involves sphingolipid metabolism. PLoS One 2012; 7:e39428. [PMID: 22808036 PMCID: PMC3393719 DOI: 10.1371/journal.pone.0039428] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Accepted: 05/22/2012] [Indexed: 01/06/2023] Open
Abstract
Magmas is a growth factor responsive gene encoding an essential mitochondrial protein in mammalian cells. Pam16, the Magmas ortholog in Saccharomyces cerevisiae, is a component of the presequence translocase-associated motor. A temperature-sensitive allele (pam16-I61N) was used to query an array of non-essential gene-deletion strains for synthetic genetic interactions. The pam16-I61N mutation at ambient temperature caused synthetic lethal or sick phenotypes with genes involved in lipid metabolism, perixosome synthesis, histone deacetylation and mitochondrial protein import. The gene deletion array was also screened for suppressors of the pam16-I61N growth defect to identify compensatory pathways. Five suppressor genes were identified (SUR4, ISC1, IPT1, SKN1, and FEN1) and all are involved in sphingolipid metabolism. pam16-I61N cells cultured in glucose at non-permissive temperatures resulted in rapid growth inhibition and G1 cell cycle arrest, but cell viability was maintained. Altered mitochondria morphology, reduced peroxisome induction in glycerol/ethanol and oleate, and changes in the levels of several sphingolipids including C18 alpha-hydroxy-phytoceramide, were also observed in the temperature sensitive strain. Deletion of SUR4, the strongest suppressor, reversed the temperature sensitive fermentative growth defect, the morphological changes and the elevated levels of C18 alpha-hydroxy phytoceramide in pam16-I61N. Deletion of the other four suppressor genes had similar effects on C18 alpha-hydroxy-phytoceramide levels and restored proliferation to the pam16-I61N strain. In addition, pam16-I61N inhibited respiratory growth, likely by reducing cardiolipin, which is essential for mitochondrial function. Our results suggest that the pleiotropic effects caused by impaired Pam16/Magmas function are mediated in part by changes in lipid metabolism.
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Affiliation(s)
- Mary K Short
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Abstract
Due to its genetic tractability and increasing wealth of accessible data, the yeast Saccharomyces cerevisiae is a model system of choice for the study of the genetics, biochemistry, and cell biology of eukaryotic lipid metabolism. Glycerolipids (e.g., phospholipids and triacylglycerol) and their precursors are synthesized and metabolized by enzymes associated with the cytosol and membranous organelles, including endoplasmic reticulum, mitochondria, and lipid droplets. Genetic and biochemical analyses have revealed that glycerolipids play important roles in cell signaling, membrane trafficking, and anchoring of membrane proteins in addition to membrane structure. The expression of glycerolipid enzymes is controlled by a variety of conditions including growth stage and nutrient availability. Much of this regulation occurs at the transcriptional level and involves the Ino2–Ino4 activation complex and the Opi1 repressor, which interacts with Ino2 to attenuate transcriptional activation of UASINO-containing glycerolipid biosynthetic genes. Cellular levels of phosphatidic acid, precursor to all membrane phospholipids and the storage lipid triacylglycerol, regulates transcription of UASINO-containing genes by tethering Opi1 to the nuclear/endoplasmic reticulum membrane and controlling its translocation into the nucleus, a mechanism largely controlled by inositol availability. The transcriptional activator Zap1 controls the expression of some phospholipid synthesis genes in response to zinc availability. Regulatory mechanisms also include control of catalytic activity of glycerolipid enzymes by water-soluble precursors, products and lipids, and covalent modification of phosphorylation, while in vivo function of some enzymes is governed by their subcellular location. Genome-wide genetic analysis indicates coordinate regulation between glycerolipid metabolism and a broad spectrum of metabolic pathways.
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45
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The yeast vacuolar Rab GTPase Ypt7p has an activity beyond membrane recruitment of the homotypic fusion and protein sorting-Class C Vps complex. Biochem J 2012; 443:205-11. [PMID: 22417749 DOI: 10.1042/bj20110687] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A previous report described lipid mixing of reconstituted proteoliposomes made using lipid mixtures that mimic the composition of yeast vacuoles. This lipid mixing required SNARE {SNAP [soluble NSF (N-ethylmaleimide-sensitive factor)-attachment protein] receptor} proteins, Sec18p and Sec17p (yeast NSF and α-SNAP) and the HOPS (homotypic fusion and protein sorting)-Class C Vps (vacuole protein sorting) complex, but not the vacuolar Rab GTPase Ypt7p. The present study investigates the activity of Ypt7p in proteoliposome lipid mixing. Ypt7p is required for the lipid mixing of proteoliposomes lacking cardiolipin [1,3-bis-(sn-3'-phosphatidyl)-sn-glycerol]. Omission of other lipids with negatively charged and/or small head groups does not cause Ypt7p dependence for lipid mixing. Yeast vacuoles made from strains disrupted for CRD1 (cardiolipin synthase) fuse to the same extent as vacuoles from strains with functional CRD1. Disruption of CRD1 does not alter dependence on Rab GTPases for vacuole fusion. It has been proposed that the recruitment of the HOPS complex to membranes is the main function of Ypt7p. However, Ypt7p is still required for lipid mixing even when the concentration of HOPS complex in lipid-mixing reactions is adjusted such that cardiolipin-free proteoliposomes with or without Ypt7p bind to equal amounts of HOPS. Ypt7p therefore must stimulate membrane fusion by a mechanism that is in addition to recruitment of HOPS to the membrane. This is the first demonstration of such a stimulatory activity--that is, beyond bulk effector recruitment--for a Rab GTPase.
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Angelini R, Corral P, Lopalco P, Ventosa A, Corcelli A. Novel ether lipid cardiolipins in archaeal membranes of extreme haloalkaliphiles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1365-73. [DOI: 10.1016/j.bbamem.2012.02.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 02/07/2012] [Accepted: 02/10/2012] [Indexed: 11/16/2022]
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Joshi AS, Thompson MN, Fei N, Hüttemann M, Greenberg ML. Cardiolipin and mitochondrial phosphatidylethanolamine have overlapping functions in mitochondrial fusion in Saccharomyces cerevisiae. J Biol Chem 2012; 287:17589-17597. [PMID: 22433850 DOI: 10.1074/jbc.m111.330167] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two non-bilayer forming mitochondrial phospholipids cardiolipin (CL) and phosphatidylethanolamine (PE) play crucial roles in maintaining mitochondrial morphology. We have shown previously that CL and PE have overlapping functions, and the loss of both is synthetically lethal. Because the lack of CL does not lead to defects in the mitochondrial network in Saccharomyces cerevisiae, we hypothesized that PE may compensate for CL in the maintenance of mitochondrial tubular morphology and fusion. To test this hypothesis, we constructed a conditional mutant crd1Δpsd1Δ containing null alleles of CRD1 (CL synthase) and PSD1 (mitochondrial phosphatidylserine decarboxylase), in which the wild type CRD1 gene is expressed on a plasmid under control of the TET(OFF) promoter. In the presence of tetracycline, the mutant exhibited highly fragmented mitochondria, loss of mitochondrial DNA, and reduced membrane potential, characteristic of fusion mutants. Deletion of DNM1, required for mitochondrial fission, restored the tubular mitochondrial morphology. Loss of CL and mitochondrial PE led to reduced levels of small and large isoforms of the fusion protein Mgm1p, possibly accounting for the fusion defect. Taken together, these data demonstrate for the first time in vivo that CL and mitochondrial PE are required to maintain tubular mitochondrial morphology and have overlapping functions in mitochondrial fusion.
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Affiliation(s)
- Amit S Joshi
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
| | - Morgan N Thompson
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
| | - Naomi Fei
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 and.
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A genome-wide immunodetection screen in S. cerevisiae uncovers novel genes involved in lysosomal vacuole function and morphology. PLoS One 2011; 6:e23696. [PMID: 21912603 PMCID: PMC3166051 DOI: 10.1371/journal.pone.0023696] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/22/2011] [Indexed: 11/19/2022] Open
Abstract
Vacuoles of yeast Saccharomyces cerevisiae are functionally analogous to mammalian lysosomes. Both are cellular organelles responsible for macromolecular degradation, ion/pH homeostasis, and stress survival. We hypothesized that undefined gene functions remain at post-endosomal stage of vacuolar events and performed a genome-wide screen directed at such functions at the late endosome and vacuole interface – ENV genes. The immunodetection screen was designed to identify mutants that internally accumulate precursor form of the vacuolar hydrolase carboxypeptidase Y (CPY). Here, we report the uncovering and initial characterizations of twelve ENV genes. The small size of the collection and the lack of genes previously identified with vacuolar events are suggestive of the intended exclusive functional interface of the screen. Most notably, the collection includes four novel genes ENV7, ENV9, ENV10, and ENV11, and three genes previously linked to mitochondrial processes – MAM3, PCP1, PPE1. In all env mutants, vesicular trafficking stages were undisturbed in live cells as assessed by invertase and active α-factor secretion, as well as by localization of the endocytic fluorescent marker FM4-64 to the vacuole. Several mutants exhibit defects in stress survival functions associated with vacuoles. Confocal fluorescence microscopy revealed the collection to be significantly enriched in vacuolar morphologies suggestive of fusion and fission defects. These include the unique phenotype of lumenal vesicles within vacuoles in the novel env9Δ mutant and severely fragmented vacuoles upon deletion of GET4, a gene recently implicated in tail anchored membrane protein insertion. Thus, our results establish new gene functions in vacuolar function and morphology, and suggest a link between vacuolar and mitochondrial events.
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Angelini R, Lopalco P, Lobasso S, Corcelli A. Direct MALDI-TOF/MS analyses of cardiolipin in intact membranes. Chem Phys Lipids 2011. [DOI: 10.1016/j.chemphyslip.2011.05.136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Graef M, Nunnari J. Mitochondria regulate autophagy by conserved signalling pathways. EMBO J 2011; 30:2101-14. [PMID: 21468027 DOI: 10.1038/emboj.2011.104] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 03/16/2011] [Indexed: 11/10/2022] Open
Abstract
Autophagy is a conserved degradative process that is crucial for cellular homeostasis and cellular quality control via the selective removal of subcellular structures such as mitochondria. We demonstrate that a regulatory link exists between mitochondrial function and autophagy in Saccharomyces cerevisiae. During amino-acid starvation, the autophagic response consists of two independent regulatory arms-autophagy gene induction and autophagic flux-and our analysis indicates that mitochondrial respiratory deficiency severely compromises both. We show that the evolutionarily conserved protein kinases Atg1, target of rapamycin kinase complex I, and protein kinase A (PKA) regulate autophagic flux, whereas autophagy gene induction depends solely on PKA. Within this regulatory network, mitochondrial respiratory deficiency suppresses autophagic flux, autophagy gene induction, and recruitment of the Atg1-Atg13 kinase complex to the pre-autophagosomal structure by stimulating PKA activity. Our findings indicate an interrelation of two common risk factors-mitochondrial dysfunction and autophagy inhibition-for ageing, cancerogenesis, and neurodegeneration.
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Affiliation(s)
- Martin Graef
- Department of Molecular and Cellular Biology, Davis University of California, Davis, CA, USA
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