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Chornyi S, Koster J, IJlst L, Waterham HR. Studying the topology of peroxisomal acyl-CoA synthetases using self-assembling split sfGFP. Histochem Cell Biol 2024; 161:133-144. [PMID: 38243092 PMCID: PMC10822792 DOI: 10.1007/s00418-023-02257-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2023] [Indexed: 01/21/2024]
Abstract
Peroxisomes are membrane-bounded organelles that contain enzymes involved in multiple lipid metabolic pathways. Several of these pathways require (re-)activation of fatty acids to coenzyme A (CoA) esters by acyl-CoA synthetases, which may take place inside the peroxisomal lumen or extraperoxisomal. The acyl-CoA synthetases SLC27A2, SLC27A4, ACSL1, and ACSL4 have different but overlapping substrate specificities and were previously reported to be localized in the peroxisomal membrane in addition to other subcellular locations. However, it has remained unclear if the catalytic acyl-CoA synthetase sites of these enzymes are facing the peroxisomal lumen or the cytosolic side of the peroxisomal membrane. To study this topology in cellulo we have developed a microscopy-based method that uses the previously developed self-assembling split superfolder (sf) green fluorescent protein (GFP) assay. We show that this self-assembling split sfGFP method can be used to study the localization as well as the topology of membrane proteins in the peroxisomal membrane, but that it is less suited to study the location of soluble peroxisomal proteins. With the method we could demonstrate that the acyl-CoA synthetase domains of the peroxisome-bound acyl-CoA synthetases SLC27A2 and SLC27A4 are oriented toward the peroxisomal lumen and the domain of ACSL1 toward the cytosol. In contrast to previous reports, ACSL4 was not found in peroxisomes.
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Affiliation(s)
- Serhii Chornyi
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam UMC-University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Janet Koster
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam UMC-University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Lodewijk IJlst
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam UMC-University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Hans R Waterham
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam UMC-University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands.
- Amsterdam Reproduction and Development, Amsterdam, The Netherlands.
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2
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Kimura T, Kimura AK, Epand RM. Systematic crosstalk in plasmalogen and diacyl lipid biosynthesis for their differential yet concerted molecular functions in the cell. Prog Lipid Res 2023; 91:101234. [PMID: 37169310 DOI: 10.1016/j.plipres.2023.101234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/29/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023]
Abstract
Plasmalogen is a major phospholipid of mammalian cell membranes. Recently it is becoming evident that the sn-1 vinyl-ether linkage in plasmalogen, contrasting to the ester linkage in the counterpart diacyl glycerophospholipid, yields differential molecular characteristics for these lipids especially related to hydrocarbon-chain order, so as to concertedly regulate biological membrane processes. A role played by NMR in gaining information in this respect, ranging from molecular to tissue levels, draws particular attention. We note here that a broad range of enzymes in de novo synthesis pathway of plasmalogen commonly constitute that of diacyl glycerophospholipid. This fact forms the basis for systematic crosstalk that not only controls a quantitative balance between these lipids, but also senses a defect causing loss of lipid in either pathway for compensation by increase of the counterpart lipid. However, this inherent counterbalancing mechanism paradoxically amplifies imbalance in differential effects of these lipids in a diseased state on membrane processes. While sharing of enzymes has been recognized, it is now possible to overview the crosstalk with growing information for specific enzymes involved. The overview provides a fundamental clue to consider cell and tissue type-dependent schemes in regulating membrane processes by plasmalogen and diacyl glycerophospholipid in health and disease.
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Affiliation(s)
- Tomohiro Kimura
- Department of Chemistry & Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, USA.
| | - Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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3
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Chornyi S, Ofman R, Koster J, Waterham HR. The origin of long-chain fatty acids required for de novo ether lipid/plasmalogen synthesis. J Lipid Res 2023; 64:100364. [PMID: 36990386 PMCID: PMC10154978 DOI: 10.1016/j.jlr.2023.100364] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023] Open
Abstract
Peroxisomes are single-membrane bounded organelles, that in humans play a dual role in lipid metabolism, including the degradation of very long-chain fatty acids and the synthesis of ether lipids/plasmalogens. The first step in de novo ether lipid synthesis is mediated by the peroxisomal enzyme glyceronephosphate O-acyltransferase, which has a strict substrate specificity reacting only with the long-chain acyl-CoAs. The aim of this study was to determine the origin of these long-chain acyl-CoAs. To this end, we developed a sensitive method for the measurement of de novo ether phospholipid synthesis in cells and, by CRISPR/Cas9 genome editing, generated a series of HeLa cell lines with deficiencies of proteins involved in peroxisomal biogenesis, beta-oxidation, ether lipid synthesis, or metabolite transport. Our results show that the long-chain acyl-CoAs required for the first step of ether lipid synthesis can be imported from the cytosol by the peroxisomal ABCD proteins, in particular ABCD3. Furthermore, we show that these acyl-CoAs can be produced intraperoxisomally by chain shortening of CoA esters of very long-chain fatty acids via beta-oxidation. Our results demonstrate that peroxisomal beta-oxidation and ether lipid synthesis are intimately connected and that the peroxisomal ABC transporters play a crucial role in de novo ether lipid synthesis.
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4
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Lee S, Cheung-See-Kit M, Williams TA, Yamout N, Zufferey R. The glycosomal alkyl-dihydroxyacetonephosphate synthase TbADS is essential for the synthesis of ether glycerophospholipids in procyclic trypanosomes. Exp Parasitol 2018; 185:71-78. [PMID: 29355496 DOI: 10.1016/j.exppara.2018.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/30/2017] [Accepted: 01/14/2018] [Indexed: 01/15/2023]
Abstract
Glycerophospholipids are the main constituents of the biological membranes in Trypanosoma brucei, which causes sleeping sickness in humans. The present work reports the characterization of the alkyl-dihydroxyacetonephosphate synthase TbADS that catalyzes the committed step in ether glycerophospholipid biosynthesis. TbADS localizes to the glycosomal lumen. TbADS complemented a null mutant of Leishmania major lacking alkyl-dihydroxyacetonephosphate synthase activity and restored the formation of normal form of the ether lipid based virulence factor lipophosphoglycan. Despite lacking alkyl-dihydroxyacetonephosphate synthase activity, a null mutant of TbADS in procyclic trypanosomes remained viable and exhibited normal growth. Comprehensive analysis of cellular glycerophospholipids showed that TbADS was involved in the biosynthesis of all ether glycerophospholipid species, primarily found in the PE and PC classes.
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Affiliation(s)
- Sungsu Lee
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Melanie Cheung-See-Kit
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Tyler A Williams
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Nader Yamout
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Rachel Zufferey
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA.
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5
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Piano V, Benjamin DI, Valente S, Nenci S, Marrocco B, Mai A, Aliverti A, Nomura DK, Mattevi A. Discovery of Inhibitors for the Ether Lipid-Generating Enzyme AGPS as Anti-Cancer Agents. ACS Chem Biol 2015; 10:2589-97. [PMID: 26322624 DOI: 10.1021/acschembio.5b00466] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dysregulated ether lipid metabolism is an important hallmark of cancer cells. Previous studies have reported that lowering ether lipid levels by genetic ablation of the ether lipid-generating enzyme alkyl-glycerone phosphate synthase (AGPS) lowers key structural and oncogenic ether lipid levels and alters fatty acid, glycerophospholipid, and eicosanoid metabolism to impair cancer pathogenicity, indicating that AGPS may be a potential therapeutic target for cancer. In this study, we have performed a small-molecule screen to identify candidate AGPS inhibitors. We have identified several lead AGPS inhibitors and have structurally characterized their interactions with the enzyme and show that these inhibitors bind to distinct portions of the active site. We further show that the lead AGPS inhibitor 1a selectively lowers ether lipid levels in several types of human cancer cells and impairs their cellular survival and migration. We provide here the first report of in situ-active pharmacological tools for inhibiting AGPS, which may provide chemical scaffolds for future AGPS inhibitor development for cancer therapy.
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Affiliation(s)
- Valentina Piano
- Department
of Biology and Biotechnology, University of Pavia, via Ferrata
9, 27100 Pavia, Italy
| | - Daniel I. Benjamin
- Program
in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, California 94720, United States
| | - Sergio Valente
- Department
of Drug Chemistry and Technologies, University “La Sapienza”, P. le A. Moro 5, Roma 00185, Italy
| | - Simone Nenci
- Department
of Biology and Biotechnology, University of Pavia, via Ferrata
9, 27100 Pavia, Italy
| | - Biagina Marrocco
- Department
of Drug Chemistry and Technologies, University “La Sapienza”, P. le A. Moro 5, Roma 00185, Italy
| | - Antonello Mai
- Department
of Drug Chemistry and Technologies, University “La Sapienza”, P. le A. Moro 5, Roma 00185, Italy
- Pasteur Institute, Cenci Bolognetti Foundation, P.le A. Moro 5, Roma 00185, Italy
| | - Alessandro Aliverti
- Department
of Biosciences, University of Milano, Via Festa del Perdono, 7, 20122 Milano, Italy
| | - Daniel K. Nomura
- Program
in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, California 94720, United States
| | - Andrea Mattevi
- Department
of Biology and Biotechnology, University of Pavia, via Ferrata
9, 27100 Pavia, Italy
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6
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Moser AB, Steinberg SJ, Watkins PA, Moser HW, Ramaswamy K, Siegmund KD, Lee DR, Ely JJ, Ryder OA, Hacia JG. Human and great ape red blood cells differ in plasmalogen levels and composition. Lipids Health Dis 2011; 10:101. [PMID: 21679470 PMCID: PMC3129581 DOI: 10.1186/1476-511x-10-101] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 06/17/2011] [Indexed: 02/06/2023] Open
Abstract
Background Plasmalogens are ether phospholipids required for normal mammalian developmental, physiological, and cognitive functions. They have been proposed to act as membrane antioxidants and reservoirs of polyunsaturated fatty acids as well as influence intracellular signaling and membrane dynamics. Plasmalogens are particularly enriched in cells and tissues of the human nervous, immune, and cardiovascular systems. Humans with severely reduced plasmalogen levels have reduced life spans, abnormal neurological development, skeletal dysplasia, impaired respiration, and cataracts. Plasmalogen deficiency is also found in the brain tissue of individuals with Alzheimer disease. Results In a human and great ape cohort, we measured the red blood cell (RBC) levels of the most abundant types of plasmalogens. Total RBC plasmalogen levels were lower in humans than bonobos, chimpanzees, and gorillas, but higher than orangutans. There were especially pronounced cross-species differences in the levels of plasmalogens with a C16:0 moiety at the sn-1 position. Humans on Western or vegan diets had comparable total RBC plasmalogen levels, but the latter group showed moderately higher levels of plasmalogens with a C18:1 moiety at the sn-1 position. We did not find robust sex-specific differences in human or chimpanzee RBC plasmalogen levels or composition. Furthermore, human and great ape skin fibroblasts showed only modest differences in peroxisomal plasmalogen biosynthetic activity. Human and chimpanzee microarray data indicated that genes involved in plasmalogen biosynthesis show cross-species differential expression in multiple tissues. Conclusion We propose that the observed differences in human and great ape RBC plasmalogens are primarily caused by their rates of biosynthesis and/or turnover. Gene expression data raise the possibility that other human and great ape cells and tissues differ in plasmalogen levels. Based on the phenotypes of humans and rodents with plasmalogen disorders, we propose that cross-species differences in tissue plasmalogen levels could influence organ functions and processes ranging from cognition to reproduction to aging.
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Affiliation(s)
- Ann B Moser
- Hugo W. Moser Research Institute at Kennedy Krieger, and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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7
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Razeto A, Mattiroli F, Carpanelli E, Aliverti A, Pandini V, Coda A, Mattevi A. The crucial step in ether phospholipid biosynthesis: structural basis of a noncanonical reaction associated with a peroxisomal disorder. Structure 2007; 15:683-92. [PMID: 17562315 DOI: 10.1016/j.str.2007.04.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 04/13/2007] [Accepted: 04/13/2007] [Indexed: 01/17/2023]
Abstract
Ether phospholipids are essential constituents of eukaryotic cell membranes. Rhizomelic chondrodysplasia punctata type 3 is a severe peroxisomal disorder caused by inborn deficiency of alkyldihydroxyacetonephosphate synthase (ADPS). The enzyme carries out the most characteristic step in ether phospholipid biosynthesis: formation of the ether bond. The crystal structure of ADPS from Dictyostelium discoideum shows a fatty-alcohol molecule bound in a narrow hydrophobic tunnel, specific for aliphatic chains of 16 carbons. Access to the tunnel is controlled by a flexible loop and a gating helix at the protein-membrane interface. Structural and mutagenesis investigations identify a cluster of hydrophilic catalytic residues, including an essential tyrosine, possibly involved in substrate proton abstraction, and the arginine that is mutated in ADPS-deficient patients. We propose that ether bond formation might be orchestrated through a covalent imine intermediate with the flavin, accounting for the noncanonical employment of a flavin cofactor in a nonredox reaction.
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MESH Headings
- Alkyl and Aryl Transferases/chemistry
- Alkyl and Aryl Transferases/genetics
- Alkyl and Aryl Transferases/metabolism
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Binding Sites
- Catalysis
- Chondrodysplasia Punctata, Rhizomelic/enzymology
- Chondrodysplasia Punctata, Rhizomelic/metabolism
- Chondrodysplasia Punctata, Rhizomelic/pathology
- Conserved Sequence
- Crystallography, X-Ray
- Dictyostelium/enzymology
- Dimerization
- Flavin-Adenine Dinucleotide/chemistry
- Flavin-Adenine Dinucleotide/metabolism
- Histidine/metabolism
- Humans
- Hydrogen Bonding
- Lipid Metabolism, Inborn Errors
- Models, Biological
- Models, Chemical
- Models, Molecular
- Molecular Sequence Data
- Molecular Structure
- Peroxisomal Disorders/enzymology
- Peroxisomal Disorders/genetics
- Phenylalanine/metabolism
- Phospholipid Ethers/chemistry
- Phospholipid Ethers/metabolism
- Protein Binding
- Protein Conformation
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Spectrum Analysis, Raman
- Substrate Specificity
- Tyrosine/metabolism
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Affiliation(s)
- Adelia Razeto
- Dipartimento di Genetica e Microbiologia, Università di Pavia, via Ferrata 1, 27100 Pavia, Italy
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8
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Vance DE, Spener F. Henk van den Bosch: chemist and biochemist. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1636:77-81. [PMID: 15164754 DOI: 10.1016/j.bbalip.2003.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Accepted: 12/05/2003] [Indexed: 11/19/2022]
Abstract
Henk van den Bosch is a native of The Netherlands and recently retired from his position as Professor at Utrecht University. This article summarizes the many scientific achievements of Dr. van den Bosch. He enjoys an international reputation for his research on phospholipases A, cardiolipin biosynthesis in eukaryotes, lysophospholipases, phosphatidylcholine biosynthesis for lung surfactant, plasmalogen biosynthesis in peroxisomes, diagnosis of peroxisomal disorders and most recently his work on alkyl-dihydroxyacetone phosphate synthase. During his research career Henk van den Bosch published approximately 280 articles and presented 110 invited lectures.
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Affiliation(s)
- Dennis E Vance
- Department of Biochemistry, Canadian Institutes of Health Research Group on Molecular and Cell Biology of Lipids, Faculty of Medicine, University of Alberta, 328 Heritage Medical Research Centre, Edmonton, Alberta, Canada T6H 5S3.
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9
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Affiliation(s)
- N Nagan
- Department of Laboratory Medicine and Pathology, Division of Clinical Biochemistry and Immunology, Mayo Foundation Clinic, Rochester, MN 55905, USA
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10
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de Vet EC, Hilkes YH, Fraaije MW, van den Bosch H. Alkyl-dihydroxyacetonephosphate synthase. Presence and role of flavin adenine dinucleotide. J Biol Chem 2000; 275:6276-83. [PMID: 10692424 DOI: 10.1074/jbc.275.9.6276] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alkyl-dihydroxyacetonephosphate synthase is a peroxisomal enzyme involved in ether lipid synthesis. It catalyzes the exchange of the acyl chain in acyl-dihydroxyacetonephosphate for a long chain fatty alcohol, yielding the first ether linked intermediate, i.e. alkyl-dihydroxyacetonephosphate, in the pathway of ether lipid biosynthesis. Although this reaction is not a net redox reaction, the amino acid sequence of the enzyme suggested the presence of a flavin adenine dinucleotide (FAD)-binding domain. In this study we show that alkyl-dihydroxyacetonephosphate synthase contains an essential FAD molecule as cofactor, which is evidenced by fluorescence properties, UV-visible absorption spectra and the observation that the enzyme activity is dependent on the presence of this cofactor in a coupled in vitro transcription/translation assay. Furthermore, we could demonstrate that the FAD cofactor directly participates in catalysis. Upon incubation of the enzyme with the substrate palmitoyl-dihydroxyacetonephosphate, the flavin moiety is reduced, indicating that in this initial step the substrate is oxidized. Stopped flow experiments show that the reduction of the flavin moiety is a monophasic process yielding a oxygen stable, reduced enzyme species. Upon addition of hexadecanol to the reduced enzyme species, the flavin moiety is efficiently reoxidized. A hypothetical reaction mechanism is proposed that is consistent with the data in this paper and with previous studies.
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Affiliation(s)
- E C de Vet
- Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands
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11
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Thai TP, Rodemer C, Worsch J, Hunziker A, Gorgas K, Just WW. Synthesis of plasmalogens in eye lens epithelial cells. FEBS Lett 1999; 456:263-8. [PMID: 10456321 DOI: 10.1016/s0014-5793(99)00968-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The present paper describes cloning and sequencing of the mouse cDNA encoding dihydroxyacetonephosphate acyltransferase (DAPAT), the peroxisomal key enzyme of plasmalogen (PM) biosynthesis. Using monospecific antibodies, we localized DAPAT and alkyl dihydroxyacetonephosphate synthase to peroxisomes of mouse lens epithelial cells (LECs) and determined their enzymatic activity. By electrospray ionization mass spectrometry of mouse lens lipid extracts, we identified phosphatidyl ethanolamine including plasmenyl ethanolamine species as major constituents. Our data demonstrate the capacity of LECs to synthesize PMs and the high coincidence between deficiency of PM and early manifestation of cataract in patients with peroxisomal disorders suggests that ether-bonded lipids may play an important role in maintaining lens transparency.
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Affiliation(s)
- T P Thai
- Biochemiezentrum Heidelberg, Universität Heidelberg, Germany
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12
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Biermann J, van den Bosch H. In vitro processing of the human alkyl-dihydroxyacetonephosphate synthase precursor. Arch Biochem Biophys 1999; 368:139-46. [PMID: 10415121 DOI: 10.1006/abbi.1999.1281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alkyl-dihydroxyacetonephosphate synthase, a peroxisomal enzyme involved in the biosynthesis of ether phospholipids, is synthesized with a cleavable N-terminal presequence containing the peroxisomal targeting signal type 2. The human alkyl-dihydroxyacetonephosphate synthase precursor produced in vitro or expressed in Escherichia coli could be processed to a lower molecular weight protein by incubation at 37 degrees C with a guinea pig liver fraction, enriched in mitochondria, lysosomes, and peroxisomes. This lower molecular weight protein was identified as the mature human alkyl-dihydroxyacetonephosphate synthase by radiosequencing, indicating that the processing protease is present in this organellar fraction. Characterization of the processing protease indicated that it is a cysteine protease with a pH optimum of 6.5. Furthermore, it was demonstrated that exogenously added pre-alkyl-dihydroxyacetonephosphate synthase was imported and processed in purified peroxisomes in vitro. Processing of alkyl-dihydroxyacetonephosphate synthase did not increase the activity of the enzyme. This indicates that the presence of the presequence does not affect the activity of the enzyme.
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Affiliation(s)
- J Biermann
- Institute for Biomembranes, Utrecht University, Utrecht, The Netherlands
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13
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Biermann J, Gootjes J, Humbel BM, Dansen TB, Wanders RJ, van den Bosch H. Immunological analyses of alkyl-dihydroxyacetone-phosphate synthase in human peroxisomal disorders. Eur J Cell Biol 1999; 78:339-48. [PMID: 10384985 DOI: 10.1016/s0171-9335(99)80068-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Alkyl-dihydroxyacetonephosphate synthase (alkyl-DHAP synthase) is a peroxisomal enzyme involved in the biosynthesis of ether phospholipids. To localize the enzyme in human peroxisomal disorders, indirect immunofluorescence and immunoblot analysis was performed. In Zellweger syndrome and rhizomelic chondrodysplasia punctata fibroblast cell lines, alkyl-DHAP synthase protein levels on immunoblots were strongly decreased and residual immunofluorescence was diffusely localized throughout the cytoplasm. In a particular neonatal adrenoleukodystrophy cell line, characterized by the absence of a functional peroxisomal targeting signal 1 receptor, the precursor form of the enzyme was detected in Western blots at levels comparable to that of the mature enzyme in control fibroblasts. Similarly, fibroblasts from patients with a single deficiency in the activity of either alkyl-DHAP synthase or DHAP-acyltransferase showed normal levels of the mature alkyl-DHAP synthase protein on immunoblots. Immunofluorescence experiments revealed a peroxisomal localization of both the precursor and the mature form of the enzyme. Collectively, these results visualize the peroxisomal localization of alkyl-DHAP synthase, indicate that the enzyme is unstable outside its target organelle and explain that normal enzyme protein levels found in some peroxisomal disorders result from protection against cytoplasmic degradation through import into peroxisomes. Additionally, alkyl-DHAP synthase could be detected in rat mesangial cells and murine NIH-3R3 fibroblasts by immunofluorescence as well as immunoblot analysis. Immunoelectron microscopy showed that the enzyme is predominantly located on the lumenal side of the peroxisomal membrane in rat and guinea pig liver.
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Affiliation(s)
- J Biermann
- Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht University, The Netherlands
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14
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Biermann J, Just WW, Wanders RJ, Van Den Bosch H. Alkyl-dihydroxyacetone phosphate synthase and dihydroxyacetone phosphate acyltransferase form a protein complex in peroxisomes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 261:492-9. [PMID: 10215861 DOI: 10.1046/j.1432-1327.1999.00295.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dihydroxyacetone phosphate (GrnP) acyltransferase and alkyl-GrnP synthase are the key enzymes involved in the biosynthesis of ether phospholipids. Both enzymes are located on the inside of the peroxisomal membrane. Here we report evidence for a direct interaction between these enzymes obtained by the use of chemical cross-linking. After cross-linking and immunoblot analysis alkyl-GrnP synthase could be detected in a 210-kDa complex which was located entirely on the lumenal side of the peroxisomal membrane. Two-dimensional SDS/PAGE demonstrated that GrnP-acyltransferase is also cross-linked in a 210-kDa complex. Co-immunoprecipitation confirmed that the two enzymes interact, in a heterotrimeric complex. Furthermore, alkyl-GrnP synthase can form a homotrimeric complex in the absence of GrnP-acyltransferase as was demonstrated by immunoblot analysis after cross-linking experiments with either GrnP-acyltransferase deficient human fibroblast homogenates or recombinant (His)6-tagged alkyl-GrnP synthase. We conclude that alkyl-GrnP synthase interacts selectively with GrnP-acyltransferase in a heterotrimeric complex and in the absence of GrnP-acyltransferase can also form a homotrimeric complex.
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Affiliation(s)
- J Biermann
- Centre for Biomembranes and Lipid Enzymology, Institut for Biomembranes, Utrecht University, The Netherlands
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15
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de Vet EC, van den Bosch H. Characterization of recombinant guinea pig alkyl-dihydroxyacetonephosphate synthase expressed in Escherichia coli. Kinetics, chemical modification and mutagenesis. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1436:299-306. [PMID: 9989261 DOI: 10.1016/s0005-2760(98)00118-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A recombinant form of guinea pig alkyl-dihydroxyacetonephosphate synthase, a key enzyme in the biosynthesis of ether phospholipids, was characterized. Kinetic analysis yielded evidence that the enzyme operates by a ping-pong rather than a sequential mechanism. Enzyme activity was irreversibly inhibited by N-ethylmaleimide, p-bromophenacylbromide and 2,4-dinitrofluorobenzene. The enzyme could be protected against the inactivation by either of these three compounds by the presence of saturating amounts of the substrate palmitoyl-dihydroxyacetonephosphate. The rate of inactivation of the enzyme by p-bromophenacylbromide was strongly pH dependent and the highest at alkaline conditions. Collectively, these results are indicative of cysteine, histidine and lysine residues, respectively, at or close to the active site. The divalent cations Mg2+, Zn2+ and Mn2+ were found to be inhibitors of enzymatic activity, whereas Ca2+ had no effect. Mutational analysis showed that histidine 617 is an essential amino acid for enzymatic activity: replacement of this residue by alanine resulted in complete loss of enzymatic activity. A recombinant enzyme with the C-terminal five amino acids deleted was shown to be inactive, indicating an important role of the C-terminus for catalytic activity.
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Affiliation(s)
- E C de Vet
- Centre for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands
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16
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Affiliation(s)
- F Snyder
- Oak Ridge Associated Universities, TN 37830, USA
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17
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de Vet EC, van den Bosch H. Nucleotide sequence of alkyl-dihydroxyacetonephosphate synthase cDNA from Dictyostelium discoideum. Biochem Biophys Res Commun 1998; 252:629-33. [PMID: 9837757 DOI: 10.1006/bbrc.1998.9670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleotide sequence is reported of alkyl-dihydroxyacetonephosphate synthase cDNA from the cellular slime mold Dictyostelium discoideum. The open reading frame encodes a protein of 611 amino acids which shows a 33% amino acid identity to the human enzyme. This D. discoideum homolog carries a variant of the peroxisomal targeting signal type 1 at its C-terminus (PKL). Expression of the cDNA in Escherichia coli yielded an enzymatically active protein.
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Affiliation(s)
- E C de Vet
- Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht University, Utrecht, The Netherlands
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18
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Lee TC. Biosynthesis and possible biological functions of plasmalogens. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1394:129-45. [PMID: 9795186 DOI: 10.1016/s0005-2760(98)00107-6] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- T C Lee
- Basic and Applied Research, Oak Ridge Institute for Science and Education/Oak Ridge Associated Universities, Oak Ridge, TN 37831-0117, USA
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19
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Biermann J, Schoonderwoerd K, Hom ML, Luthjens LH, Van den Bosch H. The native molecular size of alkyl-dihydroxyacetonephosphate synthase and dihydroxyacetonephosphate acyltransferase. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1393:137-42. [PMID: 9714777 DOI: 10.1016/s0005-2760(98)00071-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Dihydroxyacetonephosphate acyltransferase (DHAP-acyltransferase) and alkyl-dihydroxyacetonephosphate synthase (alkyl-DHAP synthase) are the first two enzymes involved in the biosynthesis of ether phospholipids. Both peroxisomal enzymes have recently been purified to homogeneity and their molecular weights under denaturing conditions were reported. To determine the in situ functional size of both enzymes, radiation inactivation experiments were performed. Alkyl-DHAP synthase showed single exponential decays, both when enzymatic activity and when immunoreactive protein levels were measured, from which target sizes of 79+/-2 kDa and 78+/-4 kDa, respectively, were calculated. DHAP-acyltransferase activity increased at lower doses and decayed upon further irradiation with an apparent target size of 62+/-7 kDa. We conclude from these data that the functional unit sizes for both enzymes in situ are represented by their single polypeptide chains.
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Affiliation(s)
- J Biermann
- Department of Biochemistry of Lipids, Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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20
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de Vet EC, Ijlst L, Oostheim W, Wanders RJ, van den Bosch H. Alkyl-dihydroxyacetonephosphate synthase. Fate in peroxisome biogenesis disorders and identification of the point mutation underlying a single enzyme deficiency. J Biol Chem 1998; 273:10296-301. [PMID: 9553082 DOI: 10.1074/jbc.273.17.10296] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peroxisomes play an indispensible role in ether lipid biosynthesis as evidenced by the deficiency of ether phospholipids in fibroblasts and tissues from patients suffering from a number of peroxisomal disorders. Alkyl-dihydroxyacetonephosphate synthase, a peroxisomal enzyme playing a key role in the biosynthesis of ether phospholipids, contains the peroxisomal targeting signal type 2 in a N-terminal cleavable presequence. Using a polyclonal antiserum raised against alkyl-dihydroxyacetonephosphate synthase, levels of this enzyme were examined in fibroblast cell lines from patients affected by peroxisomal disorders. Strongly reduced levels were found in fibroblasts of Zellweger syndrome and rhizomelic chondrodysplasia punctata patients, indicating that the enzyme is not stable in the cytoplasm as a result of defective import into peroxisomes. In a neonatal adrenoleukodystrophy patient with an isolated import deficiency of proteins carrying the peroxisomal targeting signal type 1, the precursor form of alkyl-dihydroxyacetonephosphate synthase was detected at a level comparable to that of the mature form in control fibroblasts, in line with an intraperoxisomal localization. A patient with an isolated deficiency in alkyl-dihydroxyacetonephosphate (DHAP) synthase activity had normal levels of this protein. Analysis at the cDNA level revealed a missense mutation leading to a R419H substitution in the enzyme of this patient. Expression of a recombinant protein carrying this mutation in Escherichia coli yielded an inactive enzyme, whereas a comparable control recombinant enzyme was active, providing further proof that this substitution is responsible for the inactivity of the enzyme and the phenotype. In line with this result is the observation that wild-type alkyl-DHAP synthase activity can be inactivated by the arginine-modifying agent phenylglyoxal. The enzyme is efficiently protected against this inactivation when the substrate palmitoyl-DHAP is present at a saturating concentration. The gene encoding human alkyl-dihydroxyacetonephosphate synthase was mapped on chromosome 2q31.
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Affiliation(s)
- E C de Vet
- Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht University, Utrecht, The Netherlands
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21
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Abstract
Peroxisomes were long believed to play only a minor role in cellular metabolism but it is now clear that they catalyze a number of important functions. The importance of peroxisomes in humans is stressed by the existence of a group of genetic diseases in man in which one or more peroxisomal functions are impaired. Most of the functions known to take place in peroxisomes have to do with lipids. Indeed, peroxisomes are capable of 1. fatty acid beta-oxidation 2. fatty acid alpha-oxidation 3. synthesis of cholesterol and other isoprenoids 4. ether-phospholipid synthesis and 5. biosynthesis of polyunsaturated fatty acids. In Chapters 2-6 we will discuss the functional organization and enzymology of these pathways in detail. Furthermore, attention is paid to the permeability properties of peroxisomes with special emphasis on recent studies which suggest that peroxisomes are closed structures containing specific membrane proteins for transport of metabolites. Finally, the disorders of peroxisomal lipid metabolism will be discussed.
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Affiliation(s)
- R J Wanders
- Department of Clinical Chemistry, University of Amsterdam, The Netherlands
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22
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de Vet EC, Prinsen HC, van den Bosch H. Nucleotide sequence of a cDNA clone encoding a Caenorhabditis elegans homolog of mammalian alkyl-dihydroxyacetonephosphate synthase: evolutionary switching of peroxisomal targeting signals. Biochem Biophys Res Commun 1998; 242:277-81. [PMID: 9446784 DOI: 10.1006/bbrc.1997.7950] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The nucleotide sequence is reported of a cDNA clone encoding a Caenorhabditis elegans homolog of guinea pig and human alkyl-dihydroxyacetonephosphate synthase. The open reading frame encodes a protein of 597 amino acids which shows extensive homology with the mammalian enzymes (52% identical and about 76% similar in the overlapping region). In contrast to the mammalian enzymes, which carry a consensus peroxisomal targeting signal type 2 in a cleavable N-terminal presequence, this Caenorhabditis elegans homolog carries a consensus peroxisomal targeting signal type 1 (CKL) at its C-terminus. Expression of this protein in an in vitro transcription/translation system yielded a 65 kDa protein. Recombinant aenorhabditis elegans alkyl-DHAP synthase expressed in the yeast Pichia pastoris was enzymatically active.
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Affiliation(s)
- E C de Vet
- Centre for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands
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23
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van den Bosch H, de Vet EC. Alkyl-dihydroxyacetonephosphate synthase. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1348:35-44. [PMID: 9370314 DOI: 10.1016/s0005-2760(97)00107-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mammalian ether phospholipids are characterized by a glycero-ether linkage at the sn-1-position of the glycerol backbone. In humans this type of phospholipid species occurs mainly in the ethanolamine and choline phosphoglycerides comprising an estimated 15% of total phospholipids. The glycero-ether linkage is synthesized by replacement of the acyl chain in acyl-dihydroxyacetonephosphate by a long-chain alcohol that donates the oxygen for the ether linkage. Both the enzyme that forms acyl-dihydroxyacetone phosphate (see Chapter II of this volume) and the one that introduces the glycero-ether linkage. i.e. alkyl-dihydroxyacetonephosphate synthase, are located in peroxisomes. The deficiency of ether phospholipids in human inborn errors of metabolism, caused by defects in peroxisome biogenesis, has clearly delineated the indispensable role of peroxisomes in ether phospholipid synthesis. The most characteristic enzyme of ether lipid synthesis is alkyl-dihydroxyacetonephosphate synthase. Its discovery and some of its properties, including mechanistic studies, have been discussed in recent reviews. This review recapitulates these findings and focuses on the new insights into the structure and properties of the enzyme that have recently been obtained resulting from the purification and subsequent cloning and expression of the cDNA encoding this peroxisomal enzyme.
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Affiliation(s)
- H van den Bosch
- Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, The Netherlands
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24
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de Vet EC, Biermann J, van den Bosch H. Immunological localization and tissue distribution of alkyldihydroxyacetonephosphate synthase and deficiency of the enzyme in peroxisomal disorders. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 247:511-7. [PMID: 9266692 DOI: 10.1111/j.1432-1033.1997.00511.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alkyldihydroxyacetonephosphate synthase (alkylglycerone-phosphate synthase) is a peroxisomal enzyme involved in ether phospholipid biosynthesis. The recent cloning of the cDNA encoding this enzyme from guinea pig liver enabled the raising of specific antisera against this enzyme. Both a synthetic peptide corresponding to a predicted epitope and a recombinant protein expressed in Escherichia coli were used for that purpose. Using western blot techniques, the solubilization of the enzyme from the peroxisomal membrane by Triton X-100 in the presence of salt was confirmed. Neutral hydroxylamine treatment of peroxisomes resulted in almost no release of the protein from the membrane. The complete polypeptide chain of the enzyme was resistant to proteolysis by trypsin when intact peroxisomes were studied. Carbonate treatment released alkyldihydroxyacetonephosphate synthase from the membrane indicating that the enzyme is not an integral membrane protein. This idea is in accord with the absence of a clear hydrophobic transmembrane domain in the deduced amino acid sequence of the enzyme. Alkyldihydroxyacetonephosphate synthase, as well as its mRNA, could be detected in all five guinea pig tissues examined. When using the antiserum against guinea pig recombinant alkyldihydroxyacetonephosphate synthase, a cross-reactive protein was detected in a human liver homogenate that runs at a slightly higher molecular mass. The absence of this band in liver of Zellweger syndrome and Rhizomelic chondrodysplasia punctata patients provides strong evidence that it represents the human homolog of this enzyme.
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Affiliation(s)
- E C de Vet
- Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht University, The Netherlands
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25
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Causeret C, Bentejac M, Albet S, Teubner B, Bugaut M. Copurification of dihydroxyacetone-phosphate acyl-transferase and other peroxisomal proteins from liver of fenofibrate-treated rats. Biochimie 1997; 79:423-33. [PMID: 9352092 DOI: 10.1016/s0300-9084(97)86152-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dihydroxyacetone-phosphate acyl-transferase (DHAP-AT), a peroxisomal membrane-bound enzyme that catalyzes the first step of ether-glycerolipid synthesis, was purified from liver of rats treated with fenofibrate, a peroxisome proliferator. The protocol first included isolation of peroxisomes, their purification through a discontinuous gradient and solubilization of membranes in CHAPS. DHAP-AT was further purified by four chromatographic steps, namely low-pressure size-exclusion, cation-exchange, hydroxylapatite and chromatofocusing. The chromatofocusing step led to a 4000-fold increase in the specific activity of DHAP-AT with respect to the liver homogenate with a yield of about 0.2%. Trypsin digestion of a 64-kDa protein band upon SDS-PAGE resulted in a peptide sequence unknown in databases. A corresponding degenerated oligonucleotide was used as a probe in Northern blotting, and a transcript of 3.3 kb was detected in some rat tissues. Moreover, the overall procedure allowed co-purification of four major peroxisomal enzymes: urate-oxidase, catalase, multifunctional enzyme and palmitoyl-CoA oxidase, respectively.
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Affiliation(s)
- C Causeret
- Laboratoire de Biologie Moléculaire et Cellulaire, Faculté des Sciences Mirande, Université de Bourgogne, Dijon, France
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26
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de Vet EC, van den Broek BT, van den Bosch H. Nucleotide sequence of human alkyl-dihydroxyacetonephosphate synthase cDNA reveals the presence of a peroxisomal targeting signal 2. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1346:25-9. [PMID: 9187299 DOI: 10.1016/s0005-2760(97)00014-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two overlapping clones were isolated from a human liver cDNA library in lambda gt11 that coded for human alkyl-dihydroxyacetonephosphate synthase using guinea pig and PCR-derived human cDNA probes. The open reading frame encodes a protein of 658 amino acids that shows a homology of 92% with the guinea pig homolog and a similarity of 98%. The peroxisomal targeting signal 2 that was recently identified in the presequence of the guinea pig enzyme appeared to be completely preserved in the human enzyme. Supportive confirmation for parts of the sequence of the mature protein was obtained from the Expressed Sequence Tags database of the National Center for Biotechnology Information. This database contained nine cDNA sequences, derived from seven independent clones, that correspond exactly to parts of the cDNA of human alkyl-dihydroxyacetonephosphate synthase. One of these clones most likely represents a not fully processed RNA with a putative intron containing an Alu sequence. An unexpected homology with D-lactate dehydrogenase (cytochrome C) precursor from Saccharomyces cerevisiae and with glycolate oxidase subunit D from Escherichia coli was also revealed.
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Affiliation(s)
- E C de Vet
- Department Biochemistry of Lipids, Centre for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands
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27
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de Vet EC, Zomer AW, Lahaut GJ, van den Bosch H. Polymerase chain reaction-based cloning of alkyl-dihydroxyacetonephosphate synthase complementary DNA from guinea pig liver. J Biol Chem 1997; 272:798-803. [PMID: 8995366 DOI: 10.1074/jbc.272.2.798] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Peroxisomes are indispensable organelles for ether lipid biosynthesis in mammalian tissues, and the deficiency of these organelles in a number of peroxisomal disorders leads to deficiencies in ether phospholipids. We have previously purified the committed enzyme for ether lipid biosynthesis, i.e. alkyl-dihydroxyacetone-phosphate synthase, to homogeneity. We have now determined the N-terminal amino acid sequence, as well as additional internal sequences obtained after cyanogen bromide cleavage of the enzyme. With primers directed against the N-terminal sequence and against a cyanogen bromide fragment sequence, a 1100-bp cDNA fragment was obtained by conventional polymerase chain reaction using first-strand cDNA from guinea pig liver as a template. The 5' and 3' ends of the cDNA were obtained by rapid amplification of cDNA ends. The open reading frame encodes a protein of 658 amino acids, containing the N-terminal amino acid sequence as well as the cyanogen bromide cleavage fragment sequences. The derived amino acid sequence includes a mature protein 600 amino acids long and a presequence 58 amino acids long. The latter contains a stretch of amino acids known as peroxisomal targeting signal 2. The size of the mRNA was estimated to be around 4200 nucleotides. Recombinant His-tagged alkyl-dihydroxyacetonephosphate synthase expressed in Escherichia coli was enzymatically active.
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Affiliation(s)
- E C de Vet
- Department of Biochemistry of Lipids, Centre for Biomembranes and Lipid Enzymology, Utrecht, The Netherlands
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28
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Affiliation(s)
- A K Hajra
- Mental Health Research Institute, University of Michigan, Ann Arbor 48109, USA
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29
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van den Bosch H, de Vet EC, Zomer AW. The role of peroxisomes in ether lipid synthesis. Back to the roots of PAF. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1996; 416:33-40. [PMID: 9131123 DOI: 10.1007/978-1-4899-0179-8_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- H van den Bosch
- Department Biochemistry of Lipids, Utrecht University, The Netherlands
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30
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Zomer AW, Opperdoes FR, van den Bosch H. Alkyl dihydroxyacetone phosphate synthase in glycosomes of Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1257:167-73. [PMID: 7619857 DOI: 10.1016/0005-2760(95)00066-l] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Alkyl-dihydroxyacetone phosphate synthase (E.C. 2.5.1.26), the key enzyme in ether phospholipid biosynthesis, was demonstrated to be present in Trypanosoma brucei. The distribution of alkyl-dihydroxyacetone phosphate synthase was found to be identical to that of dihydroxyacetone phosphate acyltransferase (E.C. 2.3.1.42), which has previously been shown to be exclusively associated with the glycosome fraction (Opperdoes, F.R. (1984) FEBS Lett. 169, 35-39). Studies with gradient purified glycosomes indicated that the formation of alkyl-dihydroxyacetone phosphate was completely dependent on the presence of acyl-dihydroxyacetone phosphate. The glycosomal alkyl-dihydroxyacetone phosphate synthase activity was characterized with respect to its pH optimum, Triton X-100 sensitivity and the dependency on the concentration of the substrates palmitoyl-dihydroxyacetone phosphate and hexadecanol. Using thin-layer chromatographic and alkaline hydrolysis procedures the reaction product was identified as alkyl-dihydroxyacetone phosphate. Alkyl-dihydroxyacetone phosphate synthase was resistant to proteolytic inactivation by trypsin in intact glycosomes but not in Triton X-100 disrupted glycosomes. It is concluded that T. brucei glycosomes contain the enzymes responsible for glycero-ether bond formation analogous to mammalian peroxisomes.
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Affiliation(s)
- A W Zomer
- Centre for Biomembranes and Lipid Enzymology, Utrecht, The Netherlands
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31
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Hayashi H, Oohashi M. Incorporation of acetyl-CoA generated from peroxisomal beta-oxidation into ethanolamine plasmalogen of rat liver. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1254:319-25. [PMID: 7857972 DOI: 10.1016/0005-2760(94)00194-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have reported that peroxisomal beta-oxidation has an anabolic function, supplying acetyl-CoA for biosyntheses of bile acids and phospholipids. Here we deal with its role in the biosynthesis of the subclasses of ethanolamine- and choline-containing phosphoglycerides (EPG, CPG, respectively). Rats were fed for 2 weeks on chow containing 0.25% clofibrate, which inhibits cholesterol and bile acid biosyntheses, but stimulates peroxisomal beta-oxidation. [1-14C]Lignoceric acid, which is exclusively degraded by peroxisomal beta-oxidation to acetyl-CoA, was intravenously injected, and 3 h later the rats were killed. The EPG-rich and CPG-rich fractions were prepared from the liver. When they were treated with phospholipase A2, the radioactivity was predominantly recovered in the 1-radyl group. The radioactivity in EPG was easily dissociated with HCl vapor, and the lipid containing radioactivity was found to be a fatty aldehyde mixture consisting of steary aldehyde (approx. 58%) palmityl aldehyde (approx. 40%) and oleyl aldehyde (approx. 2%). Thus, in the case of EPG, acetyl-CoA from peroxisomal beta-oxidation is incorporated mainly into the 1-alkenyl group of ethanolamine plasmalogen. The radioactivity in CPG, however, was found in fatty alcohol (formed from fatty acid), but not in alkylglycerol after reduction of the fraction with Vitride. Thus, in the case of CPG, acetyl-CoA from peroxisomal beta-oxidation is exclusively incorporated into the 1-acyl group of diacyl glycerophosphocholine, but not into the 1-alkyl group. The above results were supported by the results of phospholipase C treatment. The above data indicate that peroxisomal beta-oxidation plays a role in supplying acetyl-CoA for 1-alkenyl group of plasmalogen-type phospholipid, but this channel may open only to synthesis of EPG, and almost not to CPG.
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Affiliation(s)
- H Hayashi
- Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan
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32
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Affiliation(s)
- F Snyder
- Medical Sciences Division, Oak Ridge Associated Universities, TN 37831-0117
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33
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Abstract
Plasmalogens (1-O-1'-alkenyl-2-acylglycerophospholipids) and to a lesser extent the 1-O-alkyl analogs are ubiquitous and in some cases major constituents of mammalian cellular membranes and of anaerobic bacteria. In archaebacteria polar lipids of the cell envelope are either diphytanylglycerolipids or bipolar macrocyclic tetraether lipids capable of forming covalently linked 'bilayers'. Information on the possible role of ether lipids as membrane constituents has been obtained from studies on the biophysical properties of model membranes consisting of these lipids. In addition, effects of modified ether lipid content on properties of biological membranes have been investigated using microorganisms or mammalian cells which carry genetic defects in ether lipid biosynthesis. Differential utilization of ether glycerophospholipids by specific phospholipases might play a role in the generation of lipid mediators that are involved in signal transduction. A possible function of plasmalogens as antioxidants has been demonstrated with cultured cells and might play a role in serum lipoproteins. Synthetic ether lipid analogs exert cytostatic effects, most likely by interfering with membrane structure and by specific interaction with components of signal transmission pathways, such as phospholipase C and protein kinase C.
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Affiliation(s)
- F Paltauf
- Institut für Biochemie und Lebensmittelchemie der Technischen Universität, Graz, Austria
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