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Aleksic M, Golic I, Jankovic A, Cvoro A, Korac A. ACOX-driven peroxisomal heterogeneity and functional compartmentalization in brown adipocytes of hypothyroid rats. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230109. [PMID: 37153362 PMCID: PMC10154930 DOI: 10.1098/rsos.230109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/11/2023] [Indexed: 05/09/2023]
Abstract
We previously demonstrated that hypothyroidism increases peroxisomal biogenesis in rat brown adipose tissue (BAT). We also showed heterogeneity in peroxisomal origin and their unique structural association with mitochondria and/or lipid bodies to carry out β-oxidation, contributing thus to BAT thermogenesis. Distinctive heterogeneity creates structural compartmentalization within peroxisomal population, raising the question of whether it is followed by their functional compartmentalization regarding localization/colocalization of two main acyl-CoA oxidase (ACOX) isoforms, ACOX1 and ACOX3. ACOX is the first and rate-limiting enzyme of peroxisomal β-oxidation, and, to date, their protein expression patterns in BAT have not been fully defined. Therefore, we used methimazole-induced hypothyroidism to study ACOX1 and ACOX3 protein expression and their tissue immunolocalization. Additionally, we analysed their specific peroxisomal localization and colocalization in parallel with peroxisomal structural compartmentalization in brown adipocytes. Hypothyroidism caused a linear increase in ACOX1 expression, while a temporary decrease in ACOX3 levels is only recovered to the control level at day 21. Peroxisomal ACOX1 and ACOX3 localization and colocalization patterns entirely mirrored heterogeneous peroxisomal biogenesis pathways and structural compartmentalization, e.g. associations with mitochondria and/or lipid bodies. Hence, different ACOX isoforms localization/colocalization creates distinct functional heterogeneity of peroxisomes and drives their functional compartmentalization in rat brown adipocytes.
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Affiliation(s)
- Marija Aleksic
- Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Igor Golic
- Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Aleksandra Jankovic
- Institute for Biological Research 'Sinisa Stankovic'—National Institute of Republic of Serbia, University of Belgrade, Belgrade 11000, Serbia
| | - Aleksandra Cvoro
- Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Aleksandra Korac
- Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
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2
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Schrader TA, Carmichael RE, Schrader M. Immunolabeling for Detection of Endogenous and Overexpressed Peroxisomal Proteins in Mammalian Cells. Methods Mol Biol 2023; 2643:47-63. [PMID: 36952177 DOI: 10.1007/978-1-0716-3048-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Peroxisomes are dynamic subcellular organelles in mammals, playing essential roles in cellular lipid metabolism and redox homeostasis. They perform a wide spectrum of functions in human health and disease, with new roles, mechanisms, and regulatory pathways still being discovered. Recently elucidated biological roles of peroxisomes include as antiviral defense hubs, intracellular signaling platforms, immunomodulators, and protective organelles in sensory cells. Furthermore, peroxisomes are part of a complex inter-organelle interaction network, which involves metabolic cooperation and cross talk via membrane contacts. The detection of endogenous and/or overexpressed proteins within a cell by immunolabelling informs us about the organellar and even sub-organellar localization of both known and putative peroxisomal proteins. In turn, this can be exploited to characterize the effects of experimental manipulations on the morphology, distribution, and/or number of peroxisomes in a cell, which are key properties controlling peroxisome function. Here, we present a protocol used successfully in our laboratory for the immunolabelling of peroxisomal proteins in cultured mammalian cells. We present immunofluorescence and transfection techniques as well as reagents to determine the localization of endogenous and overexpressed peroxisomal proteins.
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Affiliation(s)
- Tina A Schrader
- Faculty of Health and Life Sciences, Biosciences, University of Exeter, Exeter, Devon, UK
| | - Ruth E Carmichael
- Faculty of Health and Life Sciences, Biosciences, University of Exeter, Exeter, Devon, UK
| | - Michael Schrader
- Faculty of Health and Life Sciences, Biosciences, University of Exeter, Exeter, Devon, UK.
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3
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Shiraishi K, Sakai Y. Autophagy as a Survival Strategy for Eukaryotic Microbes Living in the Phyllosphere. FRONTIERS IN PLANT SCIENCE 2022; 13:867486. [PMID: 35401602 PMCID: PMC8992653 DOI: 10.3389/fpls.2022.867486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Autophagy is an intracellular degradation process that is highly conserved among eukaryotes at the molecular level. The process was originally revealed in the budding yeast, but the physiological role of autophagy in yeast cells had remained unknown as autophagy-deficient yeast mutants did now show a clear growth phenotype in laboratory conditions. In this review, we introduce the role of autophagy in the methylotrophic yeast Candida boidinii grown on the leaf surface of Arabidopsis thaliana. Autophagy is shown to be required for proliferation in the phyllosphere, and selective autophagic pathways such as pexophagy and cytoplasm-to-vacuole targeting (Cvt) pathway are strictly regulated during both the daily cycle and the host plant life cycle. This review describes our current understanding of the role of autophagy as a survival strategy for phyllosphere fungi. Critical functions of autophagy for pathogen invasions are also discussed.
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Ueda K, Anderson-Baron MN, Haskins J, Hughes SC, Simmonds AJ. Recruitment of Peroxin14 to lipid droplets affects lipid storage in Drosophila. J Cell Sci 2022; 135:275042. [PMID: 35274690 DOI: 10.1242/jcs.259092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 02/20/2022] [Indexed: 10/18/2022] Open
Abstract
Both peroxisomes and lipid droplets regulate cellular lipid homeostasis. Direct inter-organellar contacts as well as novel roles for proteins associated with peroxisome or lipid droplets occur when cells are induced to liberate fatty acids from lipid droplets. We have shown a non-canonical role for as subset of peroxisome-assembly (Peroxin) proteins in this process. Transmembrane proteins Peroxin3, Peroxin13 and Peroxin14 surround newly formed lipid droplets. Trafficking of Peroxin14 to lipid droplets was enhanced by loss of Peroxin19, which directs insertion of transmembrane proteins like Peroxin14 into the peroxisome bilayer membrane. Accumulation of Peroxin14 around lipid droplets did not induce changes to peroxisome size or number, nor was co-recruitment of the remaining Peroxins needed to assemble peroxisomes observed. Increasing the relative level of Peroxin14 surrounding lipid droplets affected recruitment of Hsl lipase. Fat-body specific reduction of these lipid droplet-associated Peroxins causes a unique effect on larval fat body development and affected their survival on lipid-enriched or minimal diets.
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Affiliation(s)
- Kazuki Ueda
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta. Edmonton, AB T6G 2H7, Canada
| | - Matthew N Anderson-Baron
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta. Edmonton, AB T6G 2H7, Canada.,Future Fields, 11130 105 Ave NW, Edmonton, AB T5H 0L5, Canada
| | - Julie Haskins
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta. Edmonton, AB T6G 2H7, Canada
| | - Sarah C Hughes
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta. Edmonton, AB T6G 2H7, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta. Edmonton, AB T6G 2H7, Canada
| | - Andrew J Simmonds
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta. Edmonton, AB T6G 2H7, Canada
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5
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Joshi AS. Peroxisomal Membrane Contact Sites in Yeasts. Front Cell Dev Biol 2021; 9:735031. [PMID: 34869317 PMCID: PMC8640217 DOI: 10.3389/fcell.2021.735031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Peroxisomes are ubiquitous, single membrane-bound organelles that play a crucial role in lipid metabolism and human health. While peroxisome number is maintained by the division of existing peroxisomes, nascent peroxisomes can be generated from the endoplasmic reticulum (ER) membrane in yeasts. During formation and proliferation, peroxisomes maintain membrane contacts with the ER. In addition to the ER, contacts between peroxisomes and other organelles such as lipid droplets, mitochondria, vacuole, and plasma membrane have been reported. These membrane contact sites (MCS) are dynamic and important for cellular function. This review focuses on the recent developments in peroxisome biogenesis and the functional importance of peroxisomal MCS in yeasts.
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Affiliation(s)
- Amit S Joshi
- Department of Biochemistry and Cell and Molecular Biology, University of Tennessee, Knoxville, TN, United States
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6
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Hello from the other side: Membrane contact of lipid droplets with other organelles and subsequent functional implications. Prog Lipid Res 2021; 85:101141. [PMID: 34793861 DOI: 10.1016/j.plipres.2021.101141] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 02/06/2023]
Abstract
Lipid droplets (LDs) are ubiquitous organelles that play crucial roles in response to physiological and environmental cues. The identification of several neutral lipid synthesizing and regulatory protein complexes have propelled significant advance on the mechanisms of LD biogenesis in the endoplasmic reticulum (ER). Increasing evidence suggests that distinct proteins and regulatory factors, which localize to membrane contact sites (MCS), are involved not only in interorganellar lipid exchange and transport, but also function in other important cellular processes, including autophagy, mitochondrial dynamics and inheritance, ion signaling and inter-regulation of these MCS. More and more tethers and molecular determinants are associated to MCS and to a diversity of cellular and pathophysiological processes, demonstrating the dynamics and importance of these junctions in health and disease. The conjugation of lipids with proteins in supramolecular complexes is known to be paramount for many biological processes, namely membrane biosynthesis, cell homeostasis, regulation of organelle division and biogenesis, and cell growth. Ultimately, this physical organization allows the contact sites to function as crucial metabolic hubs that control the occurrence of chemical reactions. This leads to biochemical and metabolite compartmentalization for the purposes of energetic efficiency and cellular homeostasis. In this review, we will focus on the structural and functional aspects of LD-organelle interactions and how they ensure signaling exchange and metabolites transfer between organelles.
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Renne MF, Hariri H. Lipid Droplet-Organelle Contact Sites as Hubs for Fatty Acid Metabolism, Trafficking, and Metabolic Channeling. Front Cell Dev Biol 2021; 9:726261. [PMID: 34595176 PMCID: PMC8477659 DOI: 10.3389/fcell.2021.726261] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/12/2021] [Indexed: 01/21/2023] Open
Abstract
Cells prepare for fluctuations in nutrient availability by storing energy in the form of neutral lipids in organelles called Lipid Droplets (LDs). Upon starvation, fatty acids (FAs) released from LDs are trafficked to different cellular compartments to be utilized for membrane biogenesis or as a source of energy. Despite the biochemical pathways being known in detail, the spatio-temporal regulation of FA synthesis, storage, release, and breakdown is not completely understood. Recent studies suggest that FA trafficking and metabolism are facilitated by inter-organelle contact sites that form between LDs and other cellular compartments such as the Endoplasmic Reticulum (ER), mitochondria, peroxisomes, and lysosomes. LD-LD contact sites are also sites where FAs are transferred in a directional manner to support LD growth and expansion. As the storage site of neutral lipids, LDs play a central role in FA homeostasis. In this mini review, we highlight the role of LD contact sites with other organelles in FA trafficking, channeling, and metabolism and discuss the implications for these pathways on cellular lipid and energy homeostasis.
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Affiliation(s)
- Mike F. Renne
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
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8
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Rahman MA, Kumar R, Sanchez E, Nazarko TY. Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains. Int J Mol Sci 2021; 22:8144. [PMID: 34360917 PMCID: PMC8348048 DOI: 10.3390/ijms22158144] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 01/01/2023] Open
Abstract
Although once perceived as inert structures that merely serve for lipid storage, lipid droplets (LDs) have proven to be the dynamic organelles that hold many cellular functions. The LDs' basic structure of a hydrophobic core consisting of neutral lipids and enclosed in a phospholipid monolayer allows for quick lipid accessibility for intracellular energy and membrane production. Whereas formed at the peripheral and perinuclear endoplasmic reticulum, LDs are degraded either in the cytosol by lipolysis or in the vacuoles/lysosomes by autophagy. Autophagy is a regulated breakdown of dysfunctional, damaged, or surplus cellular components. The selective autophagy of LDs is called lipophagy. Here, we review LDs and their degradation by lipophagy in yeast, which proceeds via the micrometer-scale raft-like lipid domains in the vacuolar membrane. These vacuolar microdomains form during nutrient deprivation and facilitate internalization of LDs via the vacuolar membrane invagination and scission. The resultant intra-vacuolar autophagic bodies with LDs inside are broken down by vacuolar lipases and proteases. This type of lipophagy is called microlipophagy as it resembles microautophagy, the type of autophagy when substrates are sequestered right at the surface of a lytic compartment. Yeast microlipophagy via the raft-like vacuolar microdomains is a great model system to study the role of lipid domains in microautophagic pathways.
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Affiliation(s)
- Muhammad Arifur Rahman
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
| | - Ravinder Kumar
- Department of Obstetrics, Gynecology and Reproductive Science, University of California, San Francisco, CA 94143, USA;
| | - Enrique Sanchez
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Taras Y. Nazarko
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
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9
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The Unity of Redox and Structural Remodeling of Brown Adipose Tissue in Hypothyroidism. Antioxidants (Basel) 2021; 10:antiox10040591. [PMID: 33921249 PMCID: PMC8068806 DOI: 10.3390/antiox10040591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/30/2021] [Accepted: 04/07/2021] [Indexed: 12/20/2022] Open
Abstract
Brown adipose tissue (BAT) is important for maintaining whole-body metabolic and energy homeostasis. However, the effects of hypothyroidism, one of the most common diseases worldwide, which increases the risk of several metabolic disorders, on BAT redox and metabolic homeostasis remain mostly unknown. We aimed to investigate the dynamics of protein expression, enzyme activity, and localization of antioxidant defense (AD) enzymes in rat interscapular BAT upon induction of hypothyroidism by antithyroid drug methimazole for 7, 15, and 21 days. Our results showed an increased protein expression of CuZn- and Mn-superoxide dismutase, catalase, glutamyl-cysteine ligase, thioredoxin, total glutathione content, and activity of catalase and thioredoxin reductase in hypothyroid rats, compared to euthyroid control. Concomitant with the increase in AD, newly established nuclear, mitochondrial, and peroxisomal localization of AD enzymes was found. Hypothyroidism also potentiated associations between mitochondria, peroxisomes, and lipid bodies, creating specific structural-functional units. Moreover, hypothyroidism induced protein expression and nuclear translocation of a master regulator of redox-metabolic homeostasis, nuclear factor erythroid 2-related factor 2 (Nrf2), and an increased amount of 4-hydroxynonenal (4-HNE) protein adducts. The results indicate that spatiotemporal overlap in the remodeling of AD is orchestrated by Nrf2, implicating the role of 4-HNE in this process and suggesting the potential mechanism of redox-structural remodeling during BAT adaptation in hypothyroidism.
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10
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Jiang G, Jin Y, Li M, Wang H, Xiong M, Zeng W, Yuan H, Liu C, Ren Z, Liu C. Faster and More Specific: Excited-State Intramolecular Proton Transfer-Based Dyes for High-Fidelity Dynamic Imaging of Lipid Droplets within Cells and Tissues. Anal Chem 2020; 92:10342-10349. [PMID: 32615751 DOI: 10.1021/acs.analchem.0c00390] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lipid droplets (LDs), a type of dynamic organelle residing at the center of cellular lipid storage, have been identified to play important roles in multiple biological processes, metabolic disorders, and diseases. The highly dynamic characters of LDs were found to correspond to their physiological and pathological functions. Hence, the fluorescent probes which enable dynamic tracking of LDs should be very helpful for better understanding the mechanisms of LDs involved biological processes and diseases. Herein we present, to the best of our knowledge, the first class of excited-state intramolecular proton transfer (ESIPT) fluorescence dyes (Flp-(11-13, 19)) for dynamic imaging of LDs based on 3-hydroxyflavone (3HF) derivatives. Flp-(11-13, 19) display strong fluorescence from yellow to NIR in lipid but exhibit almost nonfluorescence in aqueous solution. Besides, they also show large Stokes shifts (>150 nm), narrow absorption and emission peaks, and good oil-water separation efficiency, which makes them specifically target and stain LDs with very low background noisy in both living cells and fixed cells. They stain intracellular LDs quite quickly (within 30 s) with very low dosage (as low as 500 nM). Benefitting from these advantages, Flp-(11-13, 19) are applied successfully in tracking the dynamic nature of LDs and accumulation of LDs in both aqueous solution and living cells, 3D imaging of LDs for visualization of their repartition within the cells, and visualizing LDs in tissues of diseases mice models including adipose, skeletal muscle, and fatty liver tissues, underscoring the potential utility of these dyes in both LDs biology research and medical diagnosis of LDs involved diseases.
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Affiliation(s)
- Gangwei Jiang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Yi Jin
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Man Li
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Huiling Wang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Mengyao Xiong
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Weili Zeng
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Hong Yuan
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Changlin Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
| | - Zhuqing Ren
- Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Chunrong Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Chemical Biology Center, College of Chemistry, and International Joint Research Center for Intelligent Biosensing Technology and Health, Central China Normal University, Wuhan 430079, P. R. China
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11
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Lundquist PK, Shivaiah KK, Espinoza-Corral R. Lipid droplets throughout the evolutionary tree. Prog Lipid Res 2020; 78:101029. [PMID: 32348789 DOI: 10.1016/j.plipres.2020.101029] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/11/2020] [Accepted: 04/18/2020] [Indexed: 12/11/2022]
Abstract
Intracellular lipid droplets are utilized for lipid storage and metabolism in organisms as evolutionarily diverse as animals, fungi, plants, bacteria, and archaea. These lipid droplets demonstrate great diversity in biological functions and protein and lipid compositions, yet fundamentally share common molecular and ultrastructural characteristics. Lipid droplet research has been largely fragmented across the diversity of lipid droplet classes and sub-classes. However, we suggest that there is great potential benefit to the lipid community in better integrating the lipid droplet research fields. To facilitate such integration, we survey the protein and lipid compositions, functional roles, and mechanisms of biogenesis across the breadth of lipid droplets studied throughout the natural world. We depict the big picture of lipid droplet biology, emphasizing shared characteristics and unique differences seen between different classes. In presenting the known diversity of lipid droplets side-by-side it becomes necessary to offer for the first time a consistent system of categorization and nomenclature. We propose a division into three primary classes that reflect their sub-cellular location: i) cytoplasmic lipid droplets (CYTO-LDs), that are present in the eukaryotic cytoplasm, ii) prokaryotic lipid droplets (PRO-LDs), that exist in the prokaryotic cytoplasm, and iii) plastid lipid droplets (PL-LDs), that are found in plant plastids, organelles of photosynthetic eukaryotes. Within each class there is a remarkable array of sub-classes displaying various sizes, shapes and compositions. A more integrated lipid droplet research field will provide opportunities to better build on discoveries and accelerate the pace of research in ways that have not been possible.
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Affiliation(s)
- Peter K Lundquist
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA.
| | - Kiran-Kumar Shivaiah
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Roberto Espinoza-Corral
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
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12
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Affiliation(s)
- Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster
- Cells-in-Motion Cluster of Excellence (EXC 1003—CiM), University of Münster
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13
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Germain K, Kim PK. Pexophagy: A Model for Selective Autophagy. Int J Mol Sci 2020; 21:ijms21020578. [PMID: 31963200 PMCID: PMC7013971 DOI: 10.3390/ijms21020578] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 01/03/2023] Open
Abstract
The removal of damaged or superfluous organelles from the cytosol by selective autophagy is required to maintain organelle function, quality control and overall cellular homeostasis. Precisely how substrate selectivity is achieved, and how individual substrates are degraded during selective autophagy in response to both extracellular and intracellular cues is not well understood. The aim of this review is to highlight pexophagy, the autophagic degradation of peroxisomes, as a model for selective autophagy. Peroxisomes are dynamic organelles whose abundance is rapidly modulated in response to metabolic demands. Peroxisomes are routinely turned over by pexophagy for organelle quality control yet can also be degraded by pexophagy in response to external stimuli such as amino acid starvation or hypoxia. This review discusses the molecular machinery and regulatory mechanisms governing substrate selectivity during both quality-control pexophagy and pexophagy in response to external stimuli, in yeast and mammalian systems. We draw lessons from pexophagy to infer how the cell may coordinate the degradation of individual substrates by selective autophagy across different cellular cues.
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Affiliation(s)
- Kyla Germain
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Peter K. Kim
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence: ; Tel.: +1-416-813-5983
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14
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15
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Chang CL, Weigel AV, Ioannou MS, Pasolli HA, Xu CS, Peale DR, Shtengel G, Freeman M, Hess HF, Blackstone C, Lippincott-Schwartz J. Spastin tethers lipid droplets to peroxisomes and directs fatty acid trafficking through ESCRT-III. J Cell Biol 2019; 218:2583-2599. [PMID: 31227594 PMCID: PMC6683741 DOI: 10.1083/jcb.201902061] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/29/2019] [Accepted: 05/28/2019] [Indexed: 12/22/2022] Open
Abstract
Lipid droplets (LDs) are neutral lipid storage organelles that transfer lipids to various organelles including peroxisomes. Here, we show that the hereditary spastic paraplegia protein M1 Spastin, a membrane-bound AAA ATPase found on LDs, coordinates fatty acid (FA) trafficking from LDs to peroxisomes through two interrelated mechanisms. First, M1 Spastin forms a tethering complex with peroxisomal ABCD1 to promote LD-peroxisome contact formation. Second, M1 Spastin recruits the membrane-shaping ESCRT-III proteins IST1 and CHMP1B to LDs via its MIT domain to facilitate LD-to-peroxisome FA trafficking, possibly through IST1- and CHMP1B-dependent modifications in LD membrane morphology. Furthermore, LD-to-peroxisome FA trafficking mediated by M1 Spastin is required to relieve LDs of lipid peroxidation. M1 Spastin's dual roles in tethering LDs to peroxisomes and in recruiting ESCRT-III components to LD-peroxisome contact sites for FA trafficking may underlie the pathogenesis of diseases associated with defective FA metabolism in LDs and peroxisomes.
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Affiliation(s)
- Chi-Lun Chang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Aubrey V Weigel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Maria S Ioannou
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - H Amalia Pasolli
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - David R Peale
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Gleb Shtengel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Melanie Freeman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Craig Blackstone
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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Joshi AS, Cohen S. Lipid Droplet and Peroxisome Biogenesis: Do They Go Hand-in-Hand? Front Cell Dev Biol 2019; 7:92. [PMID: 31214588 PMCID: PMC6554619 DOI: 10.3389/fcell.2019.00092] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/14/2019] [Indexed: 01/19/2023] Open
Abstract
All eukaryotic cells contain membrane bound structures called organelles. Each organelle has specific composition and function. Some of the organelles are generated de novo in a cell. The endoplasmic reticulum (ER) is a major contributor of proteins and membranes for most of the organelles. In this mini review, we discuss de novo biogenesis of two such organelles, peroxisomes and lipid droplets (LDs), that are formed in the ER membrane. LDs and peroxisomes are highly conserved ubiquitously present membrane-bound organelles. Both these organelles play vital roles in lipid metabolism and human health. Here, we discuss the current understanding of de novo biogenesis of LDs and peroxisomes, recent advances on how biogenesis of both the organelles might be linked, physical interaction between LDs and peroxisomes and other organelles, and their physiological importance.
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Affiliation(s)
- Amit S. Joshi
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Sarah Cohen
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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17
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Nettebrock NT, Bohnert M. Born this way - Biogenesis of lipid droplets from specialized ER subdomains. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158448. [PMID: 31028912 DOI: 10.1016/j.bbalip.2019.04.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 01/21/2023]
Abstract
Both the endoplasmic reticulum (ER) and lipid droplets (LDs) are key players in lipid handling. In addition to this functional connection, the two organelles are also tightly linked due to the fact that the ER is the birthplace of LDs. LDs have an atypical architecture, consisting of a neutral lipid core that is covered by a phospholipid monolayer. LD biogenesis starts with neutral lipid synthesis in the ER membrane and formation of small neutral lipid lenses between its leaflets, followed by budding of mature LDs toward the cytosol. Several ER proteins have been identified that are required for efficient LD formation, among them seipin, Pex30, and FIT2. Recent evidence indicates that these LD biogenesis factors might cooperate with specific lipids, thus generating ER subdomains optimized for LD assembly. Intriguingly, LD biogenesis reacts dynamically to nutrient stress, resulting in a spatial reorganization of LD formation in the ER.
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Affiliation(s)
- Niclas T Nettebrock
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Germany.
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18
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Schrul B, Schliebs W. Intracellular communication between lipid droplets and peroxisomes: the Janus face of PEX19. Biol Chem 2019; 399:741-749. [PMID: 29500918 DOI: 10.1515/hsz-2018-0125] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 02/23/2018] [Indexed: 02/06/2023]
Abstract
In order to adapt to environmental changes, such as nutrient availability, cells have to orchestrate multiple metabolic pathways, which are catalyzed in distinct specialized organelles. Lipid droplets (LDs) and peroxisomes are both endoplasmic reticulum (ER)-derived organelles that fulfill complementary functions in lipid metabolism: Upon nutrient supply, LDs store metabolic energy in the form of neutral lipids and, when energy is needed, supply fatty acids for oxidation in peroxisomes and mitochondria. How these organelles communicate with each other for a concerted metabolic output remains a central question. Here, we summarize recent insights into the biogenesis and function of LDs and peroxisomes with emphasis on the role of PEX19 in these processes.
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Affiliation(s)
- Bianca Schrul
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling (PZMS), Faculty of Medicine, Saarland University, Kirrberger Str. 100, D-66421 Homburg/Saar, Germany
| | - Wolfgang Schliebs
- Institute of Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University Bochum, D-44780 Bochum, Germany
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19
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Exner T, Romero-Brey I, Yifrach E, Rivera-Monroy J, Schrul B, Zouboulis CC, Stremmel W, Honsho M, Bartenschlager R, Zalckvar E, Poppelreuther M, Füllekrug J. An alternative membrane topology permits lipid droplet localization of peroxisomal fatty acyl-CoA reductase 1. J Cell Sci 2019; 132:jcs.223016. [PMID: 30745342 DOI: 10.1242/jcs.223016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/01/2019] [Indexed: 01/02/2023] Open
Abstract
Fatty acyl-CoA reductase 1 (Far1) is a ubiquitously expressed peroxisomal membrane protein that generates the fatty alcohols required for the biosynthesis of ether lipids. Lipid droplet localization of exogenously expressed and endogenous human Far1 was observed by fluorescence microscopy under conditions of increased triglyceride synthesis in tissue culture cells. This unexpected finding was supported further by correlative light electron microscopy and subcellular fractionation. Selective permeabilization, protease sensitivity and N-glycosylation tagging suggested that Far1 is able to assume two different membrane topologies, differing in the orientation of the short hydrophilic C-terminus towards the lumen or the cytosol, respectively. Two closely spaced hydrophobic domains are contained within the C-terminal region. When analyzed separately, the second domain was sufficient for the localization of a fluorescent reporter to lipid droplets. Targeting of Far1 to lipid droplets was not impaired in either Pex19 or ASNA1 (also known as TRC40) CRISPR/Cas9 knockout cells. In conclusion, our data suggest that Far1 is a novel member of the rather exclusive group of dual topology membrane proteins. At the same time, Far1 shows lipid metabolism-dependent differential subcellular localizations to peroxisomes and lipid droplets.
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Affiliation(s)
- Tarik Exner
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, 69120 Heidelberg, Germany
| | - Inés Romero-Brey
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Eden Yifrach
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Jhon Rivera-Monroy
- Department of Molecular Biology, University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Bianca Schrul
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling (PZMS), Saarland University, 66421 Homburg/Saar, Germany
| | - Christos C Zouboulis
- Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Brandenburg Medical School Theodor Fontane, 06847 Dessau, Germany
| | - Wolfgang Stremmel
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, 69120 Heidelberg, Germany
| | - Masanori Honsho
- Medical Institute of Bioregulation, Kyushu University, 812-8582 Fukuoka, Japan
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Margarete Poppelreuther
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, 69120 Heidelberg, Germany
| | - Joachim Füllekrug
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, 69120 Heidelberg, Germany
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20
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Varghese M, Kimler VA, Ghazi FR, Rathore GK, Perkins GA, Ellisman MH, Granneman JG. Adipocyte lipolysis affects Perilipin 5 and cristae organization at the cardiac lipid droplet-mitochondrial interface. Sci Rep 2019; 9:4734. [PMID: 30894648 PMCID: PMC6426865 DOI: 10.1038/s41598-019-41329-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 03/04/2019] [Indexed: 12/14/2022] Open
Abstract
This study investigated the effects of elevated fatty acid (FA) supply from adipose tissue on the ultrastructure of cardiac lipid droplets (LDs) and the expression and organization of LD scaffold proteins perilipin-2 (PLIN2) and perilipin-5 (PLIN5). Stimulation of adipocyte lipolysis by fasting (24 h) or β3-adrenergic receptor activation by CL316, 243 (CL) increased cardiac triacylglycerol (TAG) levels and LD size, whereas CL treatment also increased LD number. LDs were tightly associated with mitochondria, which was maintained during LD expansion. Electron tomography (ET) studies revealed continuity of LD and smooth endoplasmic reticulum (SER), suggesting interconnections among LDs. Under fed ad libitum conditions, the cristae of mitochondria that apposed LD were mostly organized perpendicularly to the tangent of the LD surface. Fasting significantly reduced, whereas CL treatment greatly increased, the perpendicular alignment of mitochondrial cristae. Fasting and CL treatment strongly upregulated PLIN5 protein and PLIN2 to a lesser extent. Immunofluorescence and immuno-electron microscopy demonstrated strong targeting of PLIN5 to the cardiac LD-mitochondrial interface, but not to the mitochondrial matrix. CL treatment augmented PLIN5 targeting to the LD-mitochondrial interface, whereas PLIN2 was not significantly affected. Together, our results support the concept that the interface between LD and cardiac mitochondria represents an organized and dynamic "metabolic synapse" that is highly responsive to FA trafficking.
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Affiliation(s)
- Mita Varghese
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Victoria A Kimler
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Fariha R Ghazi
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Gurnoor K Rathore
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, 92093, USA
| | - James G Granneman
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
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21
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Jansen RLM, Klei IJ. The peroxisome biogenesis factors Pex3 and Pex19: multitasking proteins with disputed functions. FEBS Lett 2019; 593:457-474. [DOI: 10.1002/1873-3468.13340] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/06/2019] [Accepted: 02/12/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Renate L. M. Jansen
- Molecular Cell Biology Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen The Netherlands
| | - Ida J. Klei
- Molecular Cell Biology Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen The Netherlands
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22
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Abstract
Lipid droplets are storage organelles at the centre of lipid and energy homeostasis. They have a unique architecture consisting of a hydrophobic core of neutral lipids, which is enclosed by a phospholipid monolayer that is decorated by a specific set of proteins. Originating from the endoplasmic reticulum, lipid droplets can associate with most other cellular organelles through membrane contact sites. It is becoming apparent that these contacts between lipid droplets and other organelles are highly dynamic and coupled to the cycles of lipid droplet expansion and shrinkage. Importantly, lipid droplet biogenesis and degradation, as well as their interactions with other organelles, are tightly coupled to cellular metabolism and are critical to buffer the levels of toxic lipid species. Thus, lipid droplets facilitate the coordination and communication between different organelles and act as vital hubs of cellular metabolism.
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Affiliation(s)
- James A Olzmann
- Department of Nutritional Sciences and Toxicology, University of California-Berkeley, Berkeley, CA, USA.
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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23
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Abstract
Peroxisomes are key metabolic organelles, which contribute to cellular lipid metabolism, e.g. the β-oxidation of fatty acids and the synthesis of myelin sheath lipids, as well as cellular redox balance. Peroxisomal dysfunction has been linked to severe metabolic disorders in man, but peroxisomes are now also recognized as protective organelles with a wider significance in human health and potential impact on a large number of globally important human diseases such as neurodegeneration, obesity, cancer, and age-related disorders. Therefore, the interest in peroxisomes and their physiological functions has significantly increased in recent years. In this review, we intend to highlight recent discoveries, advancements and trends in peroxisome research, and present an update as well as a continuation of two former review articles addressing the unsolved mysteries of this astonishing organelle. We summarize novel findings on the biological functions of peroxisomes, their biogenesis, formation, membrane dynamics and division, as well as on peroxisome-organelle contacts and cooperation. Furthermore, novel peroxisomal proteins and machineries at the peroxisomal membrane are discussed. Finally, we address recent findings on the role of peroxisomes in the brain, in neurological disorders, and in the development of cancer.
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Affiliation(s)
- Markus Islinger
- Institute of Neuroanatomy, Center for Biomedicine and Medical Technology Mannheim, Medical Faculty Manheim, University of Heidelberg, 68167, Mannheim, Germany
| | - Alfred Voelkl
- Institute for Anatomy and Cell Biology, University of Heidelberg, 69120, Heidelberg, Germany
| | - H Dariush Fahimi
- Institute for Anatomy and Cell Biology, University of Heidelberg, 69120, Heidelberg, Germany
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24
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Joshi AS, Nebenfuehr B, Choudhary V, Satpute-Krishnan P, Levine TP, Golden A, Prinz WA. Lipid droplet and peroxisome biogenesis occur at the same ER subdomains. Nat Commun 2018; 9:2940. [PMID: 30054481 PMCID: PMC6063926 DOI: 10.1038/s41467-018-05277-3] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 06/18/2018] [Indexed: 12/19/2022] Open
Abstract
Nascent lipid droplet (LD) formation occurs in the endoplasmic reticulum (ER) membrane but it is not known how sites of biogenesis are determined. We previously identified ER domains in S. cerevisiae containing the reticulon homology domain (RHD) protein Pex30 that are regions where preperoxisomal vesicles (PPVs) form. Here, we show that Pex30 domains are also sites where most nascent LDs form. Mature LDs usually remain associated with Pex30 subdomains, and the same Pex30 subdomain can simultaneously associate with a LD and a PPV or peroxisome. We find that in higher eukaryotes multiple C2 domain containing transmembrane protein (MCTP2) is similar to Pex30: it contains an RHD and resides in ER domains where most nascent LD biogenesis occurs and that often associate with peroxisomes. Together, these findings indicate that most LDs and PPVs form and remain associated with conserved ER subdomains, and suggest a link between LD and peroxisome biogenesis. Lipid droplets (LDs) and peroxisomes are both generated by budding off the endoplasmic reticulum (ER). Here, the authors show that the yeast protein Pex30 marks ER subdomains where both LD and peroxisome biogenesis occurs, and identify MCTP2 as the putative mammalian Pex30 ortholog.
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Affiliation(s)
- Amit S Joshi
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
| | - Benjamin Nebenfuehr
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Vineet Choudhary
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | | | - Tim P Levine
- University College London, Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Andy Golden
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - William A Prinz
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
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25
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Abstract
Long considered inert fat storage depots, it has become clear that lipid droplets (LDs) are bona fide organelles. Like other organelles, they have a characteristic complement of proteins and lipids, and undergo a life cycle that includes biogenesis, maturation, interactions with other organelles, and turnover. I will discuss recent insights into mechanisms governing the life cycle of LDs, and compare and contrast the LD life cycle with that of other metabolic organelles such as mitochondria, peroxisomes, and autophagosomes, highlighting open questions in the field.
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Affiliation(s)
- Sarah Cohen
- University of North Carolina, Chapel Hill, NC, United States.
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26
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Schuldiner M, Bohnert M. A different kind of love - lipid droplet contact sites. Biochim Biophys Acta Mol Cell Biol Lipids 2017. [PMID: 28627434 DOI: 10.1016/j.bbalip.2017.06.005] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Lipid droplets (LDs) store lipids and hence serve as energy reservoir and as a source for building-blocks for the organelle membrane systems. LD biology therefore depends on tight communication with other organelles. The unique architecture of LDs, consisting of a neutral lipid core shielded by a phospholipid-monolayer, is however an obstacle to bulk-exchange of bilayer-bounded vesicles with other organelles. In recent years, it is emerging that contact sites, places where two organelles are positioned in close proximity allowing vesicle-independent communication, are an important way to integrate LDs into the organellar landscape. However, few LD contact sites have been studied in depth and our understanding of their structure, extent and function is only starting to emerge. Here, we highlight recent findings on the functions of LD contact sites and on the proteins involved in their formation and hypothesize about the unique characteristics of the contact sites formed by these intriguing organelles. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Maria Bohnert
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
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27
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Bersuker K, Olzmann JA. Establishing the lipid droplet proteome: Mechanisms of lipid droplet protein targeting and degradation. Biochim Biophys Acta Mol Cell Biol Lipids 2017. [PMID: 28627435 DOI: 10.1016/j.bbalip.2017.06.006] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipid droplets (LDs) are ubiquitous, endoplasmic reticulum (ER)-derived organelles that mediate the sequestration of neutral lipids (e.g. triacylglycerol and sterol esters), providing a dynamic cellular storage depot for rapid lipid mobilization in response to increased cellular demands. LDs have a unique ultrastructure, consisting of a core of neutral lipids encircled by a phospholipid monolayer that is decorated with integral and peripheral proteins. The LD proteome contains numerous lipid metabolic enzymes, regulatory scaffold proteins, proteins involved in LD clustering and fusion, and other proteins of unknown functions. The cellular role of LDs is inherently determined by the composition of its proteome and alteration of the LD protein coat provides a powerful mechanism to adapt LDs to fluctuating metabolic states. Here, we review the current understanding of the molecular mechanisms that govern LD protein targeting and degradation. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Kirill Bersuker
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720, USA
| | - James A Olzmann
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720, USA.
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28
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Organelle Communication at Membrane Contact Sites (MCS): From Curiosity to Center Stage in Cell Biology and Biomedical Research. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:1-12. [DOI: 10.1007/978-981-10-4567-7_1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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29
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The size matters: regulation of lipid storage by lipid droplet dynamics. SCIENCE CHINA-LIFE SCIENCES 2016; 60:46-56. [PMID: 27981432 DOI: 10.1007/s11427-016-0322-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 10/28/2016] [Indexed: 12/14/2022]
Abstract
Adequate energy storage is essential for sustaining healthy life. Lipid droplet (LD) is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient conditions. Energy storage capacity of LDs is primarily dependent on the sizes of LDs. Enlargement and growth of LDs is controlled by two molecular pathways: neutral lipid synthesis and atypical LD fusion. Shrinkage of LDs is mediated by the degradation of neutral lipids under energy demanding conditions and is controlled by neutral cytosolic lipases and lysosomal acidic lipases. In this review, we summarize recent progress regarding the regulatory pathways and molecular mechanisms that control the sizes and the energy storage capacity of LDs.
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30
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Piecing Together the Patchwork of Contact Sites. Trends Cell Biol 2016; 27:214-229. [PMID: 27717534 DOI: 10.1016/j.tcb.2016.08.010] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/10/2016] [Accepted: 08/25/2016] [Indexed: 11/23/2022]
Abstract
Contact sites are places where two organelles join together to carry out a shared activity requiring nonvesicular communication. A large number of contact sites have been discovered, and almost any two organelles can contact each other. General rules about contacts include constraints on bridging proteins, with only a minority of bridges physically creating contacts by acting as 'tethers'. The downstream effects of contacts include changing the physical behaviour of organelles, and also forming biochemically heterogeneous subdomains. However, some functions typically localized to contact sites, such as lipid transfer, have no absolute requirement to be situated there. Therefore, the key aspect of contacts is the directness of communication, which allows metabolic channelling and collective regulation.
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31
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Cui S, Hayashi Y, Otomo M, Mano S, Oikawa K, Hayashi M, Nishimura M. Sucrose Production Mediated by Lipid Metabolism Suppresses the Physical Interaction of Peroxisomes and Oil Bodies during Germination of Arabidopsis thaliana. J Biol Chem 2016; 291:19734-45. [PMID: 27466365 DOI: 10.1074/jbc.m116.748814] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Indexed: 02/02/2023] Open
Abstract
Physical interaction between organelles is a flexible event and essential for cells to adapt rapidly to environmental stimuli. Germinating plants utilize oil bodies and peroxisomes to mobilize storage lipids for the generation of sucrose as the main energy source. Although membrane interaction between oil bodies and peroxisomes has been widely observed, its underlying molecular mechanism is largely unknown. Here we present genetic evidence for control of the physical interaction between oil bodies and peroxisomes. We identified alleles of the sdp1 mutant altered in oil body morphology. This mutant accumulates bigger and more oil body aggregates compared with the wild type and showed defects in lipid mobilization during germination. SUGAR DEPENDENT 1 (SDP1) encodes major triacylglycerol lipase in Arabidopsis Interestingly, sdp1 seedlings show enhanced physical interaction between oil bodies and peroxisomes compared with the wild type, whereas exogenous sucrose supplementation greatly suppresses the interaction. The same phenomenon occurs in the peroxisomal defective 1 (ped1) mutant, defective in lipid mobilization because of impaired peroxisomal β-oxidation, indicating that sucrose production is a key factor for oil body-peroxisomal dissociation. Peroxisomal dissociation and subsequent release from oil bodies is dependent on actin filaments. We also show that a peroxisomal ATP binding cassette transporter, PED3, is the potential anchor protein to the membranes of these organelles. Our results provide novel components linking lipid metabolism and oil body-peroxisome interaction whereby sucrose may act as a negative signal for the interaction of oil bodies and peroxisomes to fine-tune lipolysis.
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Affiliation(s)
- Songkui Cui
- From the Department of Cell Biology, National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan, the Department of Basic Biology, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Myodaiji-cho, Okazaki 444-8585, Japan, the RIKEN Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan, the Graduate School of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan, and
| | - Yasuko Hayashi
- the Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, Ninotyou, Niigata 950-2181, Japan
| | - Masayoshi Otomo
- the Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, Ninotyou, Niigata 950-2181, Japan
| | - Shoji Mano
- From the Department of Cell Biology, National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan, the Department of Basic Biology, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Myodaiji-cho, Okazaki 444-8585, Japan, the Laboratory of Biological Diversity, Department of Evolutionary Biology and Biodiversity, National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan
| | - Kazusato Oikawa
- the Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan
| | - Makoto Hayashi
- the Department of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-Cho, Nagahama 526-0829, Japan
| | - Mikio Nishimura
- From the Department of Cell Biology, National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan,
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32
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Jamdhade MD, Pawar H, Chavan S, Sathe G, Umasankar PK, Mahale KN, Dixit T, Madugundu AK, Prasad TSK, Gowda H, Pandey A, Patole MS. Comprehensive proteomics analysis of glycosomes from Leishmania donovani. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2015; 19:157-70. [PMID: 25748437 DOI: 10.1089/omi.2014.0163] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Leishmania donovani is a kinetoplastid protozoan that causes a severe and fatal disease kala-azar, or visceral leishmaniasis. L. donovani infects human host after the phlebotomine sandfly takes a blood meal and resides within the phagolysosome of infected macrophages. Previous studies on host-parasite interactions have not focused on Leishmania organelles and the role that they play in the survival of this parasite within macrophages. Leishmania possess glycosomes that are unique and specialized subcellular microbody organelles. Glycosomes are known to harbor most peroxisomal enzymes and, in addition, they also possess nine glycolytic enzymes. In the present study, we have carried out proteomic profiling using high resolution mass spectrometry of a sucrose density gradient-enriched glycosomal fraction isolated from L. donovani promastigotes. This study resulted in the identification of 4022 unique peptides, leading to the identification of 1355 unique proteins from a preparation enriched in L. donovani glycosomes. Based on protein annotation, 566 (41.8%) were identified as hypothetical proteins with no known function. A majority of the identified proteins are involved in metabolic processes such as carbohydrate, lipid, and nucleic acid metabolism. Our present proteomic analysis is the most comprehensive study to date to map the proteome of L. donovani glycosomes.
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Khan SA, Wollaston-Hayden EE, Markowski TW, Higgins L, Mashek DG. Quantitative analysis of the murine lipid droplet-associated proteome during diet-induced hepatic steatosis. J Lipid Res 2015; 56:2260-72. [PMID: 26416795 DOI: 10.1194/jlr.m056812] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Indexed: 01/17/2023] Open
Abstract
Hepatic steatosis is characterized by the accumulation of lipid droplets (LDs), which are composed of a neutral lipid core surrounded by a phospholipid monolayer embedded with many proteins. Although the LD-associated proteome has been investigated in multiple tissues and organisms, the dynamic changes in the murine LD-associated proteome in response to obesity and hepatic steatosis have not been studied. We characterized the hepatic LD-associated proteome of C57BL/6J male mouse livers following high-fat feeding using isobaric tagging for relative and absolute quantification. Of the 1,520 proteins identified with a 5% local false discovery rate, we report a total of 48 proteins that were increased and 52 proteins that were decreased on LDs in response to high-fat feeding. Most notably, ribosomal and endoplasmic reticulum proteins were increased and extracellular and cytosolic proteins were decreased in response to high-fat feeding. Additionally, many proteins involved in fatty acid catabolism or xenobiotic metabolism were enriched in the LD fraction following high-fat feeding. In contrast, proteins involved in glucose metabolism and liver X receptor or retinoid X receptor activation were decreased on LDs of high-fat-fed mice. This study provides insights into unique biological functions of hepatic LDs under normal and steatotic conditions.
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Affiliation(s)
- Salmaan Ahmed Khan
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108
| | | | - Todd W Markowski
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - LeeAnn Higgins
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - Douglas G Mashek
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108
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Schrader M, Godinho LF, Costello JL, Islinger M. The different facets of organelle interplay-an overview of organelle interactions. Front Cell Dev Biol 2015; 3:56. [PMID: 26442263 PMCID: PMC4585249 DOI: 10.3389/fcell.2015.00056] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/08/2015] [Indexed: 12/28/2022] Open
Abstract
Membrane-bound organelles such as mitochondria, peroxisomes, or the endoplasmic reticulum (ER) create distinct environments to promote specific cellular tasks such as ATP production, lipid breakdown, or protein export. During recent years, it has become evident that organelles are integrated into cellular networks regulating metabolism, intracellular signaling, cellular maintenance, cell fate decision, and pathogen defence. In order to facilitate such signaling events, specialized membrane regions between apposing organelles bear distinct sets of proteins to enable tethering and exchange of metabolites and signaling molecules. Such membrane associations between the mitochondria and a specialized site of the ER, the mitochondria associated-membrane (MAM), as well as between the ER and the plasma membrane (PAM) have been partially characterized at the molecular level. However, historical and recent observations imply that other organelles like peroxisomes, lysosomes, and lipid droplets might also be involved in the formation of such apposing membrane contact sites. Alternatively, reports on so-called mitochondria derived-vesicles (MDV) suggest alternative mechanisms of organelle interaction. Moreover, maintenance of cellular homeostasis requires the precise removal of aged organelles by autophagy—a process which involves the detection of ubiquitinated organelle proteins by the autophagosome membrane, representing another site of membrane associated-signaling. This review will summarize the available data on the existence and composition of organelle contact sites and the molecular specializations each site uses in order to provide a timely overview on the potential functions of organelle interaction.
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Affiliation(s)
- Michael Schrader
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Luis F Godinho
- Centre for Cell Biology and Department of Biology, University of Aveiro Aveiro, Portugal
| | - Joseph L Costello
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Markus Islinger
- Neuroanatomy, Center for Biomedicine and Medical Technology Mannheim, University of Heidelberg Mannheim, Germany
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No peroxisome is an island - Peroxisome contact sites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1061-9. [PMID: 26384874 DOI: 10.1016/j.bbamcr.2015.09.016] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 10/23/2022]
Abstract
In order to optimize their multiple cellular functions, peroxisomes must collaborate and communicate with the surrounding organelles. A common way of communication between organelles is through physical membrane contact sites where membranes of two organelles are tethered, facilitating exchange of small molecules and intracellular signaling. In addition contact sites are important for controlling processes such as metabolism, organelle trafficking, inheritance and division. How peroxisomes rely on contact sites for their various cellular activities is only recently starting to be appreciated and explored and the extent of peroxisomal communication, their contact sites and their functions are less characterized. In this review we summarize the identified peroxisomal contact sites, their tethering complexes and their potential physiological roles. Additionally, we highlight some of the preliminary evidence that exists in the field for unexplored peroxisomal contact sites.
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36
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Gao Q, Goodman JM. The lipid droplet-a well-connected organelle. Front Cell Dev Biol 2015; 3:49. [PMID: 26322308 PMCID: PMC4533013 DOI: 10.3389/fcell.2015.00049] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022] Open
Abstract
Our knowledge of inter-organellar communication has grown exponentially in recent years. This review focuses on the interactions that cytoplasmic lipid droplets have with other organelles. Twenty-five years ago droplets were considered simply particles of coalesced fat. Ten years ago there were hints from proteomics studies that droplets might interact with other structures to share lipids and proteins. Now it is clear that the droplets interact with many if not most cellular structures to maintain cellular homeostasis and to buffer against insults such as starvation. The evidence for this statement, as well as probes to understand the nature and results of droplet interactions, are presented.
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Affiliation(s)
- Qiang Gao
- Department of Pharmacology, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Joel M Goodman
- Department of Pharmacology, University of Texas Southwestern Medical Center Dallas, TX, USA
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37
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Bouchez I, Pouteaux M, Canonge M, Genet M, Chardot T, Guillot A, Froissard M. Regulation of lipid droplet dynamics in Saccharomyces cerevisiae depends on the Rab7-like Ypt7p, HOPS complex and V1-ATPase. Biol Open 2015; 4:764-75. [PMID: 25948753 PMCID: PMC4571102 DOI: 10.1242/bio.20148615] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
It has now been clearly shown that lipid droplets (LDs) play a dynamic role in the cell. This was reinforced by LD proteomics which suggest that a significant number of trafficking proteins are associated with this organelle. Using microscopy, we showed that LDs partly co-localize with the vacuole in S. cerevisiae. Immunoblot experiments confirmed the association of the vacuolar Rab GTPase Rab7-like Ypt7p with LDs. We observed an increase in fatty acid content and LD number in ypt7Δ mutant and also changes in LD morphology and intra LD fusions, revealing a direct role for Ypt7p in LD dynamics. Using co-immunoprecipitation, we isolated potential Ypt7p partners including, Vma13p, the H subunit of the V1 part of the vacuolar (H+) ATPase (V-ATPase). Deletion of the VMA13 gene, as well as deletion of three other subunits of the V1 part of the V-ATPase, also increased the cell fatty acid content and LD number. Mutants of the Homotypic fusion and vacuole protein sorting (HOPS) complex showed similar phenotypes. Here, we demonstrated that LD dynamics and membrane trafficking between the vacuole and LDs are regulated by the Rab7-like Ypt7p and are impaired when the HOPS complex and the V1 domain of the V-ATPase are defective.
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Affiliation(s)
- Isabelle Bouchez
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Marie Pouteaux
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Michel Canonge
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Mélanie Genet
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Thierry Chardot
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Alain Guillot
- MICALIS PAPPSO, UMR 1319 INRA, Domaine de Vilvert 78352, Jouy-en-Josas cedex, France MICALIS PAPPSO, UMR 1319 AgroParisTech, Domaine de Vilvert 78352, Jouy-en-Josas cedex, France
| | - Marine Froissard
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
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38
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Abstract
Lipid droplets/oil bodies (OBs) are lipid-storage organelles that play a crucial role as an energy resource in a variety of eukaryotic cells. Lipid stores are mobilized in the case of food deprivation or high energy demands--for example, during certain developmental processes in animals and plants. OB degradation is achieved by lipases that hydrolyze triacylglycerols (TAGs) into free fatty acids and glycerol. In the model plant Arabidopsis thaliana, Sugar-Dependent 1 (SDP1) was identified as the major TAG lipase involved in lipid reserve mobilization during seedling establishment. Although the enzymatic activity of SDP1 is associated with the membrane of OBs, its targeting to the OB surface remains uncharacterized. Here we demonstrate that the core retromer, a complex involved in protein trafficking, participates in OB biogenesis, lipid store degradation, and SDP1 localization to OBs. We also report an as-yet-undescribed mechanism for lipase transport in eukaryotic cells, with SDP1 being first localized to the peroxisome membrane at early stages of seedling growth and then possibly moving to the OB surface through peroxisome tubulations. Finally, we show that the timely transfer of SDP1 to the OB membrane requires a functional core retromer. In addition to revealing previously unidentified functions of the retromer complex in plant cells, our work provides unanticipated evidence for the role of peroxisome dynamics in interorganelle communication and protein transport.
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39
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Loizides-Mangold U, Clément S, Alfonso-Garcia A, Branche E, Conzelmann S, Parisot C, Potma EO, Riezman H, Negro F. HCV 3a core protein increases lipid droplet cholesteryl ester content via a mechanism dependent on sphingolipid biosynthesis. PLoS One 2014; 9:e115309. [PMID: 25522003 PMCID: PMC4270764 DOI: 10.1371/journal.pone.0115309] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/21/2014] [Indexed: 12/22/2022] Open
Abstract
Hepatitis C virus (HCV) infected patients often develop steatosis and the HCV core protein alone can induce this phenomenon. To gain new insights into the pathways leading to steatosis, we performed lipidomic profiling of HCV core protein expressing-Huh-7 cells and also assessed the lipid profile of purified lipid droplets isolated from HCV 3a core expressing cells. Cholesteryl esters, ceramides and glycosylceramides, but not triglycerides, increased specifically in cells expressing the steatogenic HCV 3a core protein. Accordingly, inhibitors of cholesteryl ester biosynthesis such as statins and acyl-CoA cholesterol acyl transferase inhibitors prevented the increase of cholesteryl ester production and the formation of large lipid droplets in HCV core 3a-expressing cells. Furthermore, inhibition of de novo sphingolipid biosynthesis by myriocin - but not of glycosphingolipid biosynthesis by miglustat - affected both lipid droplet size and cholesteryl ester level. The lipid profile of purified lipid droplets, isolated from HCV 3a core-expressing cells, confirmed the particular increase of cholesteryl ester. Thus, both sphingolipid and cholesteryl ester biosynthesis are affected by the steatogenic core protein of HCV genotype 3a. These results may explain the peculiar lipid profile of HCV-infected patients with steatosis.
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Affiliation(s)
- Ursula Loizides-Mangold
- Department of Biochemistry, NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Sophie Clément
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Alba Alfonso-Garcia
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States of America
| | - Emilie Branche
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Stéphanie Conzelmann
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Clotilde Parisot
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Eric O. Potma
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States of America
| | - Howard Riezman
- Department of Biochemistry, NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Francesco Negro
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
- Divisions of Gastroenterology and Hepatology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
- * E-mail:
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40
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Koch B, Schmidt C, Daum G. Storage lipids of yeasts: a survey of nonpolar lipid metabolism in Saccharomyces cerevisiae, Pichia pastoris, and Yarrowia lipolytica. FEMS Microbiol Rev 2014; 38:892-915. [PMID: 24597968 DOI: 10.1111/1574-6976.12069] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/21/2014] [Accepted: 02/21/2014] [Indexed: 11/29/2022] Open
Abstract
Biosynthesis and storage of nonpolar lipids, such as triacylglycerols (TG) and steryl esters (SE), have gained much interest during the last decades because defects in these processes are related to severe human diseases. The baker's yeast Saccharomyces cerevisiae has become a valuable tool to study eukaryotic lipid metabolism because this single-cell microorganism harbors many enzymes and pathways with counterparts in mammalian cells. In this article, we will review aspects of TG and SE metabolism and turnover in the yeast that have been known for a long time and combine them with new perceptions of nonpolar lipid research. We will provide a detailed insight into the mechanisms of nonpolar lipid synthesis, storage, mobilization, and degradation in the yeast S. cerevisiae. The central role of lipid droplets (LD) in these processes will be addressed with emphasis on the prevailing view that this compartment is more than only a depot for TG and SE. Dynamic and interactive aspects of LD with other organelles will be discussed. Results obtained with S. cerevisiae will be complemented by recent investigations of nonpolar lipid research with Yarrowia lipolytica and Pichia pastoris. Altogether, this review article provides a comprehensive view of nonpolar lipid research in yeast.
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Affiliation(s)
- Barbara Koch
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
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41
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Abstract
Peroxisomes are often dismissed as the cellular hoi polloi, relegated to cleaning up reactive oxygen chemical debris discarded by other organelles. However, their functions extend far beyond hydrogen peroxide metabolism. Peroxisomes are intimately associated with lipid droplets and mitochondria, and their ability to carry out fatty acid oxidation and lipid synthesis, especially the production of ether lipids, may be critical for generating cellular signals required for normal physiology. Here, we review the biology of peroxisomes and their potential relevance to human disorders including cancer, obesity-related diabetes, and degenerative neurologic disease.
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42
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Boncompain G, Müller C, Meas-Yedid V, Schmitt-Kopplin P, Lazarow PB, Subtil A. The intracellular bacteria Chlamydia hijack peroxisomes and utilize their enzymatic capacity to produce bacteria-specific phospholipids. PLoS One 2014; 9:e86196. [PMID: 24465954 PMCID: PMC3900481 DOI: 10.1371/journal.pone.0086196] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/06/2013] [Indexed: 12/15/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen responsible for loss of eyesight through trachoma and for millions of cases annually of sexually transmitted diseases. The bacteria develop within a membrane-bounded inclusion. They lack enzymes for several biosynthetic pathways, including those to make some phospholipids, and exploit their host to compensate. Three-dimensional fluorescence microscopy demonstrates that small organelles of the host, peroxisomes, are translocated into the Chlamydia inclusion and are found adjacent to the bacteria. In cells deficient for peroxisome biogenesis the bacteria are able to multiply and give rise to infectious progeny, demonstrating that peroxisomes are not essential for bacterial development in vitro. Mass spectrometry-based lipidomics reveal the presence in C. trachomatis of plasmalogens, ether phospholipids whose synthesis begins in peroxisomes and have never been described in aerobic bacteria before. Some of the bacterial plasmalogens are novel structures containing bacteria-specific odd-chain fatty acids; they are not made in uninfected cells nor in peroxisome-deficient cells. Their biosynthesis is thus accomplished by the metabolic collaboration of peroxisomes and bacteria.
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Affiliation(s)
- Gaelle Boncompain
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
| | - Constanze Müller
- Department of BioGeoChemistry and Analytics, Institut für Ökologische Chemie, Helmholtz Zentrum München, Neuherberg, Germany
| | - Vannary Meas-Yedid
- CNRS URA 2582, Paris, France
- Institut Pasteur, Unité Analyse d'images quantitative, Paris, France
| | - Philippe Schmitt-Kopplin
- Department of BioGeoChemistry and Analytics, Institut für Ökologische Chemie, Helmholtz Zentrum München, Neuherberg, Germany
| | - Paul B. Lazarow
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
- * E-mail: (PBL); (AS)
| | - Agathe Subtil
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
- * E-mail: (PBL); (AS)
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43
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Kuroiwa T, Ohnuma M, Imoto Y, Kuroiwa H. Lipid Droplet Formation in Cells of the Filamentous Green Alga Klebsormidium nitens as Revealed by BODIOY-DiOC6 and BODIPY-Nile Red Double-Staining Microscopy. CYTOLOGIA 2014. [DOI: 10.1508/cytologia.79.501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Tsuneyoshi Kuroiwa
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency
- Faculty of Science, Rikkyo University
| | - Mio Ohnuma
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency
- Faculty of Science, Rikkyo University
| | - Yuuta Imoto
- Department of Integrated Biosciences, Graduate School of Frontier Science, University of Tokyo
- Faculty of Science, Rikkyo University
| | - Haruko Kuroiwa
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency
- Faculty of Science, Rikkyo University
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44
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Dietrich D, Seiler F, Essmann F, Dodt G. Identification of the kinesin KifC3 as a new player for positioning of peroxisomes and other organelles in mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:3013-3024. [PMID: 23954441 DOI: 10.1016/j.bbamcr.2013.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 07/19/2013] [Accepted: 08/02/2013] [Indexed: 01/25/2023]
Abstract
The attachment of organelles to the cytoskeleton and directed organelle transport is essential for cellular morphology and function. In contrast to other cell organelles like the endoplasmic reticulum or the Golgi apparatus, peroxisomes are evenly distributed in the cytoplasm, which is achieved by binding of peroxisomes to microtubules and their bidirectional transport by the microtubule motor proteins kinesin-1 (Kif5) and cytoplasmic dynein. KifC3, belonging to the group of C-terminal kinesins, has been identified to interact with the human peroxin PEX1 in a yeast two-hybrid screen. We investigated the potential involvement of KifC3 in peroxisomal transport. Interaction of KifC3 and the AAA-protein (ATPase associated with various cellular activities) PEX1 was confirmed by in vivo colocalization and by coimmunoprecipitation from cell lysates. Furthermore, knockdown of KifC3 using RNAi resulted in an increase of cells with perinuclear-clustered peroxisomes, indicating enhanced minus-end directed motility of peroxisomes. The occurrence of this peroxisomal phenotype was cell cycle phase independent, while microtubules were essential for phenotype formation. We conclude that KifC3 may play a regulatory role in minus-end directed peroxisomal transport for example by blocking the motor function of dynein at peroxisomes. Knockdown of KifC3 would then lead to increased minus-end directed peroxisomal transport and cause the observed peroxisomal clustering at the microtubule-organizing center.
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Affiliation(s)
- Denise Dietrich
- Interfaculty Institute of Biochemistry, Cell Biochemistry, University of Tuebingen, D-72076 Tuebingen, Germany
| | - Florian Seiler
- Interfaculty Institute of Biochemistry, Cell Biochemistry, University of Tuebingen, D-72076 Tuebingen, Germany
| | - Frank Essmann
- Interfaculty Institute of Biochemistry, Molecular Medicine, University of Tuebingen, D-72076 Tuebingen, Germany
| | - Gabriele Dodt
- Interfaculty Institute of Biochemistry, Cell Biochemistry, University of Tuebingen, D-72076 Tuebingen, Germany.
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45
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Charcot-Marie-Tooth disease-associated mutants of GDAP1 dissociate its roles in peroxisomal and mitochondrial fission. EMBO Rep 2013; 14:545-52. [PMID: 23628762 DOI: 10.1038/embor.2013.56] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 03/13/2013] [Accepted: 04/11/2013] [Indexed: 11/08/2022] Open
Abstract
Mitochondria and peroxisomes can be fragmented by the process of fission. The fission machineries of both organelles share a set of proteins. GDAP1 is a tail-anchored protein of mitochondria and induces mitochondrial fragmentation. Mutations in GDAP1 lead to Charcot-Marie-Tooth disease (CMT), an inherited peripheral neuropathy, and affect mitochondrial dynamics. Here, we show that GDAP1 is also targeted to peroxisomes mediated by the import receptor Pex19. Knockdown of GDAP1 leads to peroxisomal elongation that can be rescued by re-expressing GDAP1 and by missense mutated forms found in CMT patients. GDAP1-induced peroxisomal fission is dependent on the integrity of its hydrophobic domain 1, and on Drp1 and Mff, as is mitochondrial fission. Thus, GDAP1 regulates mitochondrial and peroxisomal fission by a similar mechanism. However, our results reveal also a more critical role of the amino-terminal GDAP1 domains, carrying most CMT-causing mutations, in the regulation of mitochondrial compared to peroxisomal fission.
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46
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Schrader M, Grille S, Fahimi HD, Islinger M. Peroxisome interactions and cross-talk with other subcellular compartments in animal cells. Subcell Biochem 2013; 69:1-22. [PMID: 23821140 DOI: 10.1007/978-94-007-6889-5_1] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Peroxisomes are remarkably plastic and dynamic organelles, which fulfil important functions in hydrogen peroxide and lipid metabolism rendering them essential for human health and development. Despite great advances in the identification and characterization of essential components and molecular mechanisms associated with the biogenesis and function of peroxisomes, our understanding of how peroxisomes are incorporated into metabolic pathways and cellular communication networks is just beginning to emerge. Here we address the interaction of peroxisomes with other subcellular compartments including the relationship with the endoplasmic reticulum, the peroxisome-mitochondria connection and the association with lipid droplets. We highlight metabolic cooperations and potential cross-talk and summarize recent findings on peroxisome-peroxisome interactions and the interaction of peroxisomes with microtubules in mammalian cells.
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Affiliation(s)
- Michael Schrader
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK,
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47
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Abstract
Peroxisomes are remarkably versatile cell organelles whose size, shape, number, and protein content can vary greatly depending on the organism, the developmental stage of the organism’s life cycle, and the environment in which the organism lives. The main functions usually associated with peroxisomes include the metabolism of lipids and reactive oxygen species. However, in recent years, it has become clear that these organelles may also act as intracellular signaling platforms that mediate developmental decisions by modulating extraperoxisomal concentrations of several second messengers. To fulfill their functions, peroxisomes physically and functionally interact with other cell organelles, including mitochondria and the endoplasmic reticulum. Defects in peroxisome dynamics can lead to organelle dysfunction and have been associated with various human disorders. The purpose of this paper is to thoroughly summarize and discuss the current concepts underlying peroxisome formation, multiplication, and degradation. In addition, this paper will briefly highlight what is known about the interplay between peroxisomes and other cell organelles and explore the physiological and pathological implications of this interorganellar crosstalk.
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Affiliation(s)
- Marc Fransen
- Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, P.O. Box 601, 3000 Leuven, Belgium
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48
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Bonekamp NA, Sampaio P, de Abreu FV, Lüers GH, Schrader M. Transient complex interactions of mammalian peroxisomes without exchange of matrix or membrane marker proteins. Traffic 2012; 13:960-78. [PMID: 22435684 DOI: 10.1111/j.1600-0854.2012.01356.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 03/18/2012] [Accepted: 03/21/2012] [Indexed: 11/29/2022]
Abstract
Peroxisomes and mitochondria show a much closer interrelationship than previously anticipated. They co-operate in the metabolism of fatty acids and reactive oxygen species, but also share components of their fission machinery. If peroxisomes - like mitochondria - also fuse in mammalian cells is a matter of debate and was not yet systematically investigated. To examine potential peroxisomal fusion and interactions in mammalian cells, we established an in vivo fusion assay based on hybridoma formation by cell fusion. Fluorescence microscopy in time course experiments revealed a merge of different peroxisomal markers in fused cells. However, live cell imaging revealed that peroxisomes were engaged in transient and long-term contacts, without exchanging matrix or membrane markers. Computational analysis showed that transient peroxisomal interactions are complex and can potentially contribute to the homogenization of the peroxisomal compartment. However, peroxisomal interactions do not increase after fatty acid or H(2) O(2) treatment. Additionally, we provide the first evidence that mitochondrial fusion proteins do not localize to peroxisomes. We conclude that mammalian peroxisomes do not fuse with each other in a mechanism similar to mitochondrial fusion. However, they show an extensive degree of interaction, the implication of which is discussed.
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Affiliation(s)
- Nina A Bonekamp
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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49
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Lazarow PB. Viruses exploiting peroxisomes. Curr Opin Microbiol 2011; 14:458-69. [PMID: 21824805 DOI: 10.1016/j.mib.2011.07.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 07/05/2011] [Indexed: 11/29/2022]
Abstract
Viruses that are of great importance for global public health, including HIV, influenza and rotavirus, appear to exploit a remarkable organelle, the peroxisome, during intracellular replication in human cells. Peroxisomes are sites of lipid biosynthesis and catabolism, reactive oxygen metabolism, and other metabolic pathways. Viral proteins are targeted to peroxisomes (the spike protein of rotavirus) or interact with peroxisomal proteins (HIV's Nef and influenza's NS1) or use the peroxisomal membrane for RNA replication. The Nef interaction correlates strongly with the crucial Nef function of CD4 downregulation. Viral exploitation of peroxisomal lipid metabolism appears likely. Mostly, functional significance and mechanisms remain to be elucidated. Recently, peroxisomes were discovered to play a crucial role in the innate immune response by signaling the presence of intracellular virus, leading to the first rapid antiviral response. This review unearths, interprets and connects old data, in the hopes of stimulating new and promising research.
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Affiliation(s)
- Paul B Lazarow
- Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
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The putative Saccharomyces cerevisiae hydrolase Ldh1p is localized to lipid droplets. EUKARYOTIC CELL 2011; 10:770-5. [PMID: 21478430 DOI: 10.1128/ec.05038-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here, we report the identification of a novel hydrolase in Saccharomyces cerevisiae. Ldh1p (systematic name, Ybr204cp) comprises the typical GXSXG-type lipase motif of members of the α/β-hydrolase family and shares some features with the peroxisomal lipase Lpx1p. Both proteins carry a putative peroxisomal targeting signal type1 (PTS1) and can be aligned with two regions of homology. While Lpx1p is known as a peroxisomal enzyme, subcellular localization studies revealed that Ldh1p is predominantly localized to lipid droplets, the storage compartment of nonpolar lipids. Ldh1p is not required for the function and biogenesis of peroxisomes, and targeting of Ldh1p to lipid droplets occurs independently of the PTS1 receptor Pex5p.
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