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Kelso C, Maccarone AT, de Kroon AIPM, Mitchell TW, Renne MF. Temperature adaptation of yeast phospholipid molecular species at the acyl chain positional level. FEBS Lett 2024. [PMID: 39673166 DOI: 10.1002/1873-3468.15060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 10/02/2024] [Accepted: 10/22/2024] [Indexed: 12/16/2024]
Abstract
Yeast is a poikilothermic organism and adapts its lipid composition to the environmental temperature to maintain membrane physical properties. Studies addressing temperature-dependent adaptation of the lipidome have described changes in the phospholipid composition at the level of sum composition (e.g. PC 32:1) and molecular composition (e.g. PC 16:0_16:1). However, there is little information at the level of positional isomers (e.g. PC 16:0/16:1 versus PC 16:1/16:0). Here, we used collision- and ozone-induced dissociation (CID/OzID) mass spectrometry to investigate homeoviscous adaptation of PC, PE and PS to determine the phospholipid acyl chains at the sn-1 and sn-2 position. Our data establish the sn-molecular species composition of PC, PE and PS in the lipidome of yeast cultured at different temperatures.
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Affiliation(s)
- Celine Kelso
- School of Chemistry and Molecular Bioscience, University of Wollongong, Australia
- Molecular Horizons Institute, University of Wollongong, Australia
| | - Alan T Maccarone
- School of Chemistry and Molecular Bioscience, University of Wollongong, Australia
- Molecular Horizons Institute, University of Wollongong, Australia
| | - Anton I P M de Kroon
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, The Netherlands
| | - Todd W Mitchell
- Molecular Horizons Institute, University of Wollongong, Australia
- School of Medical, Indigenous and Health Sciences, University of Wollongong, Australia
| | - Mike F Renne
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, The Netherlands
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
- Preclinical Center for Molecular Signalling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
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2
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iPLA2-VIA is required for healthy aging of neurons, muscle, and the female germline in Drosophila melanogaster. PLoS One 2021; 16:e0256738. [PMID: 34506510 PMCID: PMC8432841 DOI: 10.1371/journal.pone.0256738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 08/13/2021] [Indexed: 11/19/2022] Open
Abstract
Neurodegenerative disease (ND) is a growing health burden worldwide, but its causes and treatments remain elusive. Although most cases of ND are sporadic, rare familial cases have been attributed to single genes, which can be investigated in animal models. We have generated a new mutation in the calcium-independent phospholipase A2 (iPLA2) VIA gene CG6718, the Drosophila melanogaster ortholog of human PLA2G6/PARK14, mutations in which cause a suite of NDs collectively called PLA2G6-associated neurodegeneration (PLAN). Our mutants display age-related loss of climbing ability, a symptom of neurodegeneration in flies. Although phospholipase activity commonly is presumed to underlie iPLA2-VIA function, locomotor decline in our mutants is rescued by a transgene carrying a serine-to-alanine mutation in the catalytic residue, suggesting that important functional aspects are independent of phospholipase activity. Additionally, we find that iPLA2-VIA knockdown in either muscle or neurons phenocopies locomotor decline with age, demonstrating its necessity in both neuronal and non-neuronal tissues. Furthermore, RNA in situ hybridization shows high endogenous iPLA2-VIA mRNA expression in adult germ cells, and transgenic HA-tagged iPLA2-VIA colocalizes with mitochondria there. Mutant males are fertile with normal spermatogenesis, while fertility is reduced in mutant females. Mutant female germ cells display age-related mitochondrial aggregation, loss of mitochondrial potential, and elevated cell death. These results suggest that iPLA2-VIA is critical for mitochondrial integrity in the Drosophila female germline, which may provide a novel context to investigate its functions with parallels to PLAN.
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3
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FSH1 encodes lysophospholipase activity in Saccharomyces cerevisiae. Biotechnol Lett 2020; 43:279-286. [PMID: 32920715 DOI: 10.1007/s10529-020-03004-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/08/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVES To elucidate the role of FSH1 (family of serine hydrolase) in lipid homeostasis. RESULTS Proteins in various species containing alpha/beta hydrolase domain are known to be involved in lipid metabolism. In silico analysis of the FSH1 gene in Saccharomyces cerevisiae revealed the presence of alpha/beta hydrolase domain (ABHD) and a lipase motif (GXSXG), however its function in lipid metabolism remained elusive. The overexpression of FSH1 in WT and fsh1Δ cells showed a significant reduction in the cellular phospholipid levels and an increase in the triacylglycerol levels and lipid droplet (LD) number. Furthermore, the purified recombinant protein Fsh1p was identified as a lysophospholipase that specifically acts on lysophosphatidylserine (LPS) and impacts the lipid homeostasis in S. cerevisiae. CONCLUSIONS These results depicted that Fsh1p has a role on lipid homeostasis and is a lysophospholipase that hydrolyzes lysophosphatidylserine (LPS).
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4
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Patton-Vogt J, de Kroon AIPM. Phospholipid turnover and acyl chain remodeling in the yeast ER. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158462. [PMID: 31146038 PMCID: PMC10716787 DOI: 10.1016/j.bbalip.2019.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/01/2019] [Accepted: 05/15/2019] [Indexed: 12/14/2022]
Abstract
The turnover of phospholipids plays an essential role in membrane lipid homeostasis by impacting both lipid head group and acyl chain composition. This review focusses on the degradation and acyl chain remodeling of the major phospholipid classes present in the ER membrane of the reference eukaryote Saccharomyces cerevisiae, i.e. phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE). Phospholipid turnover reactions are introduced, and the occurrence and important functions of phospholipid remodeling in higher eukaryotes are briefly summarized. After presenting an inventory of established mechanisms of phospholipid acyl chain exchange, current knowledge of phospholipid degradation and remodeling by phospholipases and acyltransferases localized to the yeast ER is summarized. PC is subject to the PC deacylation-reacylation remodeling pathway (PC-DRP) involving a phospholipase B, the recently identified glycerophosphocholine acyltransferase Gpc1p, and the broad specificity acyltransferase Ale1p. PI is post-synthetically enriched in C18:0 acyl chains by remodeling reactions involving Cst26p. PE may undergo turnover by the phospholipid: diacylglycerol acyltransferase Lro1p as first step in acyl chain remodeling. Clues as to the functions of phospholipid acyl chain remodeling are discussed.
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Affiliation(s)
- Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA, USA
| | - Anton I P M de Kroon
- Membrane Biochemistry & Biophysics, Bijvoet Center and Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands.
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5
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Kwiatek JM, Han GS, Carman GM. Phosphatidate-mediated regulation of lipid synthesis at the nuclear/endoplasmic reticulum membrane. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158434. [PMID: 30910690 PMCID: PMC6755077 DOI: 10.1016/j.bbalip.2019.03.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 03/14/2019] [Indexed: 12/11/2022]
Abstract
In yeast and higher eukaryotes, phospholipids and triacylglycerol are derived from phosphatidate at the nuclear/endoplasmic reticulum membrane. In de novo biosynthetic pathways, phosphatidate is channeled into membrane phospholipids via its conversion to CDP-diacylglycerol. Its dephosphorylation to diacylglycerol is required for the synthesis of triacylglycerol as well as for the synthesis of phosphatidylcholine and phosphatidylethanolamine via the Kennedy pathway. In addition to the role of phosphatidate as a precursor, it is a regulatory molecule in the transcriptional control of phospholipid synthesis genes via the Henry regulatory circuit. Pah1 phosphatidate phosphatase and Dgk1 diacylglycerol kinase are key players that function counteractively in the control of the phosphatidate level at the nuclear/endoplasmic reticulum membrane. Loss of Pah1 phosphatidate phosphatase activity not only affects triacylglycerol synthesis but also disturbs the balance of the phosphatidate level, resulting in the alteration of lipid synthesis and related cellular defects. The pah1Δ phenotypes requiring Dgk1 diacylglycerol kinase exemplify the importance of the phosphatidate level in the misregulation of cellular processes. The catalytic function of Pah1 requires its translocation from the cytoplasm to the nuclear/endoplasmic reticulum membrane, which is regulated through its phosphorylation in the cytoplasm by multiple protein kinases as well as through its dephosphorylation by the membrane-associated Nem1-Spo7 protein phosphatase complex. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
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Affiliation(s)
- Joanna M Kwiatek
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA.
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6
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Xiang S, Xu Y, Liao X, Zheng X, Chen L, Li S. Dynamic Monitoring of the Oxidation Process of Phosphatidylcholine Using SERS Analysis. Anal Chem 2018; 90:13751-13758. [PMID: 30350609 DOI: 10.1021/acs.analchem.8b04216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphatidylcholine oxidation is closely related to many neurodegenerative diseases. In this paper, Raman spectroscopy was proposed to continuously monitor the oxidation of phosphatidylcholine and provide deep understanding of this biochemical process. To increase the detection sensitivity, surface-enhanced Raman spectroscopy (SERS) with a micro-nanosilver-complex substrate was prepared by electrodeposition. The prepared SERS substrate had an enhancement factor as high as 7.8 × 107, ensuring detection sensitivity in the phosphatidylcholine-oxidation process. It was illustrated that the oxidation of phosphatidylcholine in an ethanol-water solution under the experimental conditions could be monitored and well described by second-order kinetics by continuously measuring and analyzing the SERS spectra of phosphatidylcholine-oxidation intermediates in 20 days. Meanwhile, the oxidation products were confirmed by mass spectrometry, and the oxidation process was in good concordance with mass-spectrometry detection. The use of SERS in following a biochemical process has advantages, including simple instrumentation, a low cost, a short detection time, and no sample pretreatment. Therefore, as a kind of vibration spectrum, SERS is preferable to traditional detection approaches such as MS, HPLC, and MRI for the dynamic monitoring and analysis of complex biochemical processes.
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Affiliation(s)
- Songtao Xiang
- Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology, Key Laboratory for Optoelectronic Technology and Systems of Ministry of Education , Chongqing University , Chongqing 400044 , China.,School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 400044 , China.,International R&D center of Micro-nano Systems and New Materials Technology , Chongqing University , Chongqing 400044 , China
| | - Yi Xu
- Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology, Key Laboratory for Optoelectronic Technology and Systems of Ministry of Education , Chongqing University , Chongqing 400044 , China.,School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 400044 , China.,School of Optoelectronic Engineering , Chongqing University , Chongqing 400044 , China.,International R&D center of Micro-nano Systems and New Materials Technology , Chongqing University , Chongqing 400044 , China
| | - Xin Liao
- Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology, Key Laboratory for Optoelectronic Technology and Systems of Ministry of Education , Chongqing University , Chongqing 400044 , China.,School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 400044 , China.,International R&D center of Micro-nano Systems and New Materials Technology , Chongqing University , Chongqing 400044 , China
| | - Xiangquan Zheng
- Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology, Key Laboratory for Optoelectronic Technology and Systems of Ministry of Education , Chongqing University , Chongqing 400044 , China.,School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 400044 , China.,International R&D center of Micro-nano Systems and New Materials Technology , Chongqing University , Chongqing 400044 , China
| | - Li Chen
- School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 400044 , China.,School of Optoelectronic Engineering , Chongqing University , Chongqing 400044 , China.,International R&D center of Micro-nano Systems and New Materials Technology , Chongqing University , Chongqing 400044 , China
| | - Shunbo Li
- School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 400044 , China.,School of Optoelectronic Engineering , Chongqing University , Chongqing 400044 , China.,International R&D center of Micro-nano Systems and New Materials Technology , Chongqing University , Chongqing 400044 , China
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7
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Gaspar ML, Chang YF, Jesch SA, Aregullin M, Henry SA. Interaction between repressor Opi1p and ER membrane protein Scs2p facilitates transit of phosphatidic acid from the ER to mitochondria and is essential for INO1 gene expression in the presence of choline. J Biol Chem 2017; 292:18713-18728. [PMID: 28924045 DOI: 10.1074/jbc.m117.809970] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/08/2017] [Indexed: 12/20/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, the Opi1p repressor controls the expression of INO1 via the Opi1p/Ino2p-Ino4p regulatory circuit. Inositol depletion favors Opi1p interaction with both Scs2p and phosphatidic acid at the endoplasmic reticulum (ER) membrane. Inositol supplementation, however, favors the translocation of Opi1p from the ER into the nucleus, where it interacts with the Ino2p-Ino4p complex, attenuating transcription of INO1 A strain devoid of Scs2p (scs2Δ) and a mutant, OPI1FFAT, lacking the ability to interact with Scs2p were utilized to examine the specific role(s) of the Opi1p-Scs2p interaction in the regulation of INO1 expression and overall lipid metabolism. Loss of the Opi1p-Scs2p interaction reduced INO1 expression and conferred inositol auxotrophy. Moreover, inositol depletion in strains lacking this interaction resulted in Opi1p being localized to sites of lipid droplet formation, coincident with increased synthesis of triacylglycerol. Supplementation of choline to inositol-depleted growth medium led to decreased TAG synthesis in all three strains. However, in strains lacking the Opi1p-Scs2p interaction, Opi1p remained in the nucleus, preventing expression of INO1 These data support the conclusion that a specific pool of phosphatidic acid, associated with lipid droplet formation in the perinuclear ER, is responsible for the initial rapid exit of Opi1p from the nucleus to the ER and is required for INO1 expression in the presence of choline. Moreover, the mitochondria-specific phospholipid, cardiolipin, was significantly reduced in both strains compromised for Opi1p-Scs2p interaction, indicating that this interaction is required for the transfer of phosphatidic acid from the ER to the mitochondria for cardiolipin synthesis.
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Affiliation(s)
- Maria L Gaspar
- From the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Yu-Fang Chang
- From the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Stephen A Jesch
- From the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Manuel Aregullin
- From the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Susan A Henry
- From the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
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8
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Fazzari M, Khoo NKH, Woodcock SR, Jorkasky DK, Li L, Schopfer FJ, Freeman BA. Nitro-fatty acid pharmacokinetics in the adipose tissue compartment. J Lipid Res 2016; 58:375-385. [PMID: 27913584 DOI: 10.1194/jlr.m072058] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/07/2016] [Indexed: 01/14/2023] Open
Abstract
Electrophilic nitro-FAs (NO2-FAs) promote adaptive and anti-inflammatory cell signaling responses as a result of an electrophilic character that supports posttranslational protein modifications. A unique pharmacokinetic profile is expected for NO2-FAs because of an ability to undergo reversible reactions including Michael addition with cysteine-containing proteins and esterification into complex lipids. Herein, we report via quantitative whole-body autoradiography analysis of rats gavaged with radiolabeled 10-nitro-[14C]oleic acid, preferential accumulation in adipose tissue over 2 weeks. To better define the metabolism and incorporation of NO2-FAs and their metabolites in adipose tissue lipids, adipocyte cultures were supplemented with 10-nitro-oleic acid (10-NO2-OA), nitro-stearic acid, nitro-conjugated linoleic acid, and nitro-linolenic acid. Then, quantitative HPLC-MS/MS analysis was performed on adipocyte neutral and polar lipid fractions, both before and after acid hydrolysis of esterified FAs. NO2-FAs preferentially incorporated in monoacyl- and diacylglycerides, while reduced metabolites were highly enriched in triacylglycerides. This differential distribution profile was confirmed in vivo in the adipose tissue of NO2-OA-treated mice. This pattern of NO2-FA deposition lends new insight into the unique pharmacokinetics and pharmacologic actions that could be expected for this chemically-reactive class of endogenous signaling mediators and synthetic drug candidates.
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Affiliation(s)
- Marco Fazzari
- Fondazione Ri.MED, 90133 Palermo, Italy.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Nicholas K H Khoo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Steven R Woodcock
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | | | - Lihua Li
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Francisco J Schopfer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Bruce A Freeman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
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9
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Sivachenko A, Gordon HB, Kimball SS, Gavin EJ, Bonkowsky JL, Letsou A. Neurodegeneration in a Drosophila model of adrenoleukodystrophy: the roles of the Bubblegum and Double bubble acyl-CoA synthetases. Dis Model Mech 2016; 9:377-87. [PMID: 26893370 PMCID: PMC4852500 DOI: 10.1242/dmm.022244] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 02/17/2016] [Indexed: 12/21/2022] Open
Abstract
Debilitating neurodegenerative conditions with metabolic origins affect millions of individuals worldwide. Still, for most of these neurometabolic disorders there are neither cures nor disease-modifying therapies, and novel animal models are needed for elucidation of disease pathology and identification of potential therapeutic agents. To date, metabolic neurodegenerative disease has been modeled in animals with only limited success, in part because existing models constitute analyses of single mutants and have thus overlooked potential redundancy within metabolic gene pathways associated with disease. Here, we present the first analysis of a very-long-chain acyl-CoA synthetase (ACS) double mutant. We show that the Drosophila bubblegum(bgm) and double bubble(dbb) genes have overlapping functions, and that the consequences of double knockout of both bubblegum and double bubble in the fly brain are profound, affecting behavior and brain morphology, and providing the best paradigm to date for an animal model of adrenoleukodystrophy (ALD), a fatal childhood neurodegenerative disease associated with the accumulation of very-long-chain fatty acids. Using this more fully penetrant model of disease to interrogate brain morphology at the level of electron microscopy, we show that dysregulation of fatty acid metabolism via disruption of ACS function in vivois causal of neurodegenerative pathologies that are evident in both neuronal cells and their supporting cell populations, and leads ultimately to lytic cell death in affected areas of the brain. Finally, in an extension of our model system to the study of human disease, we describe our identification of an individual with leukodystrophy who harbors a rare mutation in SLC27a6(encoding a very-long-chain ACS), a human homolog of bgm and dbb.
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Affiliation(s)
- Anna Sivachenko
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Hannah B Gordon
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Suzanne S Kimball
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Erin J Gavin
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Joshua L Bonkowsky
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84112, USA
| | - Anthea Letsou
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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10
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Topaloglu AK, Lomniczi A, Kretzschmar D, Dissen GA, Kotan LD, McArdle CA, Koc AF, Hamel BC, Guclu M, Papatya ED, Eren E, Mengen E, Gurbuz F, Cook M, Castellano JM, Kekil MB, Mungan NO, Yuksel B, Ojeda SR. Loss-of-function mutations in PNPLA6 encoding neuropathy target esterase underlie pubertal failure and neurological deficits in Gordon Holmes syndrome. J Clin Endocrinol Metab 2014; 99:E2067-75. [PMID: 25033069 PMCID: PMC5393493 DOI: 10.1210/jc.2014-1836] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Gordon Holmes syndrome (GHS) is characterized by cerebellar ataxia/atrophy and normosmic hypogonadotropic hypogonadism (nHH). The underlying pathophysiology of this combined neurodegeneration and nHH remains unknown. OBJECTIVE We aimed to provide insight into the disease mechanism in GHS. METHODS We studied a cohort of 6 multiplex families with GHS through autozygosity mapping and whole-exome sequencing. RESULTS We identified 6 patients from 3 independent families carrying loss-of-function mutations in PNPLA6, which encodes neuropathy target esterase (NTE), a lysophospholipase that maintains intracellular phospholipid homeostasis by converting lysophosphatidylcholine to glycerophosphocholine. Wild-type PNPLA6, but not PNPLA6 bearing these mutations, rescued a well-established Drosophila neurodegenerative phenotype caused by the absence of sws, the fly ortholog of mammalian PNPLA6. Inhibition of NTE activity in the LβT2 gonadotrope cell line diminished LH response to GnRH by reducing GnRH-stimulated LH exocytosis, without affecting GnRH receptor signaling or LHβ synthesis. CONCLUSION These results suggest that NTE-dependent alteration of phospholipid homeostasis in GHS causes both neurodegeneration and impaired LH release from pituitary gonadotropes, leading to nHH.
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Affiliation(s)
- A Kemal Topaloglu
- Division of Pediatric Endocrinology (A.K.T., E.M., F.G., N.O.M., B.Y.) and Department of Neurology (A.F.K.), Faculty of Medicine, and Department of Biotechnology (A.K.T., L.D.K., M.B.K.), Institute of Sciences, Cukurova University, 01330 Adana, Turkey; Division of Neuroscience (A.L., G.A.D., S.R.O.), Oregon National Primate Research Centre, Beaverton, Oregon 97006; Oregon Institute of Occupational Health Sciences (D.K., M.C.), Oregon Health and Science University, Portland, Oregon 97239; Laboratories for Integrative Neuroscience and Endocrinology (C.A.M.), School of Clinical Sciences, University of Bristol, Bristol, United Kingdom BS1 3NY; Department of Human Genetics (B.C.H.), Nijmegen Medical Centre, Radboud University, Nijmegen, The Netherlands 6525 GA; Departments of Endocrinology and Metabolism (M.G.) and Pediatric Endocrinology and Metabolism (E.D.P., E.E.), School of Medicine, Uludag University, Bursa, Turkey 16110; and Department of Cell Biology, Physiology, and Immunology (J.M.C.), University of Cordoba, Cordoba, Spain 14071
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11
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Fernández-Murray JP, Ngo MH, McMaster CR. Choline transport activity regulates phosphatidylcholine synthesis through choline transporter Hnm1 stability. J Biol Chem 2013; 288:36106-15. [PMID: 24187140 DOI: 10.1074/jbc.m113.499855] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Choline is a precursor for the synthesis of phosphatidylcholine through the CDP-choline pathway. Saccharomyces cerevisiae expresses a single high affinity choline transporter at the plasma membrane, encoded by the HNM1 gene. We show that exposing cells to increasing levels of choline results in two different regulatory mechanisms impacting Hnm1 activity. Initial exposure to choline results in a rapid decrease in Hnm1-mediated transport at the level of transporter activity, whereas chronic exposure results in Hnm1 degradation through an endocytic mechanism that depends on the ubiquitin ligase Rsp5 and the casein kinase 1 redundant pair Yck1/Yck2. We present details of how the choline transporter is a major regulator of phosphatidylcholine synthesis.
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Affiliation(s)
- J Pedro Fernández-Murray
- From the Department of Pharmacology, Atlantic Research Centre, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
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12
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Checks and balances in membrane phospholipid class and acyl chain homeostasis, the yeast perspective. Prog Lipid Res 2013; 52:374-94. [PMID: 23631861 DOI: 10.1016/j.plipres.2013.04.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 03/28/2013] [Accepted: 04/16/2013] [Indexed: 11/24/2022]
Abstract
Glycerophospholipids are the most abundant membrane lipid constituents in most eukaryotic cells. As a consequence, phospholipid class and acyl chain homeostasis are crucial for maintaining optimal physical properties of membranes that in turn are crucial for membrane function. The topic of this review is our current understanding of membrane phospholipid homeostasis in the reference eukaryote Saccharomyces cerevisiae. After introducing the physical parameters of the membrane that are kept in optimal range, the properties of the major membrane phospholipids and their contributions to membrane structure and dynamics are summarized. Phospholipid metabolism and known mechanisms of regulation are discussed, including potential sensors for monitoring membrane physical properties. Special attention is paid to processes that maintain the phospholipid class specific molecular species profiles, and to the interplay between phospholipid class and acyl chain composition when yeast membrane lipid homeostasis is challenged. Based on the reviewed studies, molecular species selectivity of the lipid metabolic enzymes, and mass action in acyl-CoA metabolism are put forward as important intrinsic contributors to membrane lipid homeostasis.
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13
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Bohdanowicz M, Grinstein S. Role of Phospholipids in Endocytosis, Phagocytosis, and Macropinocytosis. Physiol Rev 2013; 93:69-106. [DOI: 10.1152/physrev.00002.2012] [Citation(s) in RCA: 198] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Endocytosis, phagocytosis, and macropinocytosis are fundamental processes that enable cells to sample their environment, eliminate pathogens and apoptotic bodies, and regulate the expression of surface components. While a great deal of effort has been devoted over many years to understanding the proteins involved in these processes, the important contribution of phospholipids has only recently been appreciated. This review is an attempt to collate and analyze the rapidly emerging evidence documenting the role of phospholipids in clathrin-mediated endocytosis, phagocytosis, and macropinocytosis. A primer on phospholipid biosynthesis, catabolism, subcellular distribution, and transport is presented initially, for reference, together with general considerations of the effects of phospholipids on membrane curvature and charge. This is followed by a detailed analysis of the critical functions of phospholipids in the internalization processes and in the maturation of the resulting vesicles and vacuoles as they progress along the endo-lysosomal pathway.
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Affiliation(s)
- Michal Bohdanowicz
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
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14
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Mora G, Scharnewski M, Fulda M. Neutral lipid metabolism influences phospholipid synthesis and deacylation in Saccharomyces cerevisiae. PLoS One 2012; 7:e49269. [PMID: 23139841 PMCID: PMC3489728 DOI: 10.1371/journal.pone.0049269] [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: 04/27/2012] [Accepted: 10/07/2012] [Indexed: 12/29/2022] Open
Abstract
Establishment and maintenance of equilibrium in the fatty acid (FA) composition of phospholipids (PL) requires both regulation of the substrate available for PL synthesis (the acyl-CoA pool) and extensive PL turnover and acyl editing. In the present study, we utilize acyl-CoA synthetase (ACS) deficient cells, unable to recycle FA derived from lipid deacylation, to evaluate the role of several enzymatic activities in FA trafficking and PL homeostasis in Saccharomyces cerevisiae. The data presented show that phospholipases B are not contributing to constitutive PL deacylation and are therefore unlikely to be involved in PL remodeling. In contrast, the enzymes of neutral lipid (NL) synthesis and mobilization are central mediators of FA trafficking. The phospholipid:DAG acyltransferase (PDAT) Lro1p has a substantial effect on FA release and on PL equilibrium, emerging as an important mediator in PL remodeling. The acyl-CoA dependent biosynthetic activities of NL metabolism are also involved in PL homeostasis through active modulation of the substrate available for PL synthesis. In addition TAG mobilization makes an important contribution, especially in cells from stationary phase, to FA availability. Beyond its well-established role in the formation of a storage pool, NL metabolism could play a crucial role as a mechanism to uncouple the pools of PL and acyl-CoAs from each other and thereby to allow independent regulation of each one.
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Affiliation(s)
- Gabriel Mora
- Department of Plant Biochemistry, Albrecht-von-Haller Institute, Georg-August University Goettingen, Goettingen, Germany
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15
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Abstract
Due to its genetic tractability and increasing wealth of accessible data, the yeast Saccharomyces cerevisiae is a model system of choice for the study of the genetics, biochemistry, and cell biology of eukaryotic lipid metabolism. Glycerolipids (e.g., phospholipids and triacylglycerol) and their precursors are synthesized and metabolized by enzymes associated with the cytosol and membranous organelles, including endoplasmic reticulum, mitochondria, and lipid droplets. Genetic and biochemical analyses have revealed that glycerolipids play important roles in cell signaling, membrane trafficking, and anchoring of membrane proteins in addition to membrane structure. The expression of glycerolipid enzymes is controlled by a variety of conditions including growth stage and nutrient availability. Much of this regulation occurs at the transcriptional level and involves the Ino2–Ino4 activation complex and the Opi1 repressor, which interacts with Ino2 to attenuate transcriptional activation of UASINO-containing glycerolipid biosynthetic genes. Cellular levels of phosphatidic acid, precursor to all membrane phospholipids and the storage lipid triacylglycerol, regulates transcription of UASINO-containing genes by tethering Opi1 to the nuclear/endoplasmic reticulum membrane and controlling its translocation into the nucleus, a mechanism largely controlled by inositol availability. The transcriptional activator Zap1 controls the expression of some phospholipid synthesis genes in response to zinc availability. Regulatory mechanisms also include control of catalytic activity of glycerolipid enzymes by water-soluble precursors, products and lipids, and covalent modification of phosphorylation, while in vivo function of some enzymes is governed by their subcellular location. Genome-wide genetic analysis indicates coordinate regulation between glycerolipid metabolism and a broad spectrum of metabolic pathways.
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16
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Abstract
Lipid droplets (LDs) are emerging as dynamic cellular organelles that play a key role in lipid and membrane homeostasis. Abnormal lipid droplet dynamics are associated with the pathophysiology of many metabolic diseases, such as obesity, diabetes, atherosclerosis, fatty liver, and even cancer. Understanding the molecular mechanisms governing the dynamics of LDs, namely, their biogenesis, growth, maintenance, and degradation, will not only shed light on the cellular functions of LDs, but also provide additional clues to treatment of metabolic diseases. Genome-wide screen is a powerful approach to identify genetic factors that regulate lipid droplet dynamics. Here, we summarize recent genome-wide studies using yeast and Drosophila cells to understand the cellular dynamics of LDs. The results suggest that the genome-wide screens should be carried out in multiple organisms or cells, and using different nutritional conditions.
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Affiliation(s)
- Weihua Fei
- School of Biotechnology and Biomolecular Sciences, the University of New SouthWales, Sydney, Australia
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17
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Abstract
The yeast Saccharomyces cerevisiae, with its full complement of organelles, synthesizes membrane phospholipids by pathways that are generally common to those found in higher eukaryotes. Phospholipid synthesis in yeast is regulated in response to a variety of growth conditions (e.g., inositol supplementation, zinc depletion, and growth stage) by a coordination of genetic (e.g., transcriptional activation and repression) and biochemical (e.g., activity modulation and localization) mechanisms. Phosphatidate (PA), whose cellular levels are controlled by the activities of key phospholipid synthesis enzymes, plays a central role in the transcriptional regulation of phospholipid synthesis genes. In addition to the regulation of gene expression, phosphorylation of key phospholipid synthesis catalytic and regulatory proteins controls the metabolism of phospholipid precursors and products.
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Affiliation(s)
- George M Carman
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901, USA.
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18
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Hermansson M, Hokynar K, Somerharju P. Mechanisms of glycerophospholipid homeostasis in mammalian cells. Prog Lipid Res 2011; 50:240-57. [DOI: 10.1016/j.plipres.2011.02.004] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 02/21/2011] [Accepted: 02/25/2011] [Indexed: 01/09/2023]
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19
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Gulshan K, Moye-Rowley WS. Vacuolar import of phosphatidylcholine requires the ATP-binding cassette transporter Ybt1. Traffic 2011; 12:1257-68. [PMID: 21649806 DOI: 10.1111/j.1600-0854.2011.01228.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
ATP-binding cassette (ABC) transporters are well known for their roles as multidrug resistance determinants but also play important roles in regulation of lipid levels. In the yeast Saccharomyces cerevisiae, the plasma membrane ABC transporter proteins Pdr5 and Yor1 are required for normal rates of transport of phosphatidyethanolamine to the surface of the cell. Loss of these ABC transporters causes a defect in phospholipid asymmetry across the plasma membrane and has been linked with slowed rates of trafficking of other membrane proteins. Four ABC transporter proteins are found on the limiting membrane of the yeast vacuole and loss of one of these vacuolar ABC transporters, Ybt1, caused a major defect in the normal delivery of the phosphatidylcholine (PC) analog NBD-PC (7-nitro-2,1,3-benzoxadiazol-PC) to the lumen of the vacuole. NBD-PC accumulates on cytosolic membranes in an ybt1Δ strain. We demonstrated that Ybt1 is required to import NBD-PC into vacuoles in the presence of ATP in vitro. Loss of Ybt1 prevented vacuolar remodeling of PC analogs. Turnover of Ybt1 was reduced under conditions in which function of this vacuolar remodeling pathway was required. Our data describe a novel vacuolar route for lipid remodeling and reutilization in addition to previously described enzymatic avenues in the cytoplasm.
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Affiliation(s)
- Kailash Gulshan
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, 6-530 Bowen Science Building, University of Iowa, Iowa City, IA 52246, USA
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20
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Murakami M, Taketomi Y, Miki Y, Sato H, Hirabayashi T, Yamamoto K. Recent progress in phospholipase A₂ research: from cells to animals to humans. Prog Lipid Res 2010; 50:152-92. [PMID: 21185866 DOI: 10.1016/j.plipres.2010.12.001] [Citation(s) in RCA: 368] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian genomes encode genes for more than 30 phospholipase A₂s (PLA₂s) or related enzymes, which are subdivided into several classes including low-molecular-weight secreted PLA₂s (sPLA₂s), Ca²+-dependent cytosolic PLA₂s (cPLA₂s), Ca²+-independent PLA₂s (iPLA₂s), platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA₂s, and a recently identified adipose-specific PLA. Of these, the intracellular cPLA₂ and iPLA₂ families and the extracellular sPLA₂ family are recognized as the "big three". From a general viewpoint, cPLA₂α (the prototypic cPLA₂ plays a major role in the initiation of arachidonic acid metabolism, the iPLA₂ family contributes to membrane homeostasis and energy metabolism, and the sPLA₂ family affects various biological events by modulating the extracellular phospholipid milieus. The cPLA₂ family evolved along with eicosanoid receptors when vertebrates first appeared, whereas the diverse branching of the iPLA₂ and sPLA₂ families during earlier eukaryote development suggests that they play fundamental roles in life-related processes. During the past decade, data concerning the unexplored roles of various PLA₂ enzymes in pathophysiology have emerged on the basis of studies using knockout and transgenic mice, the use of specific inhibitors, and information obtained from analysis of human diseases caused by mutations in PLA₂ genes. This review focuses on current understanding of the emerging biological functions of PLA₂s and related enzymes.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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21
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Fakas S, Konstantinou C, Carman GM. DGK1-encoded diacylglycerol kinase activity is required for phospholipid synthesis during growth resumption from stationary phase in Saccharomyces cerevisiae. J Biol Chem 2010; 286:1464-74. [PMID: 21071438 DOI: 10.1074/jbc.m110.194308] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the yeast Saccharomyces cerevisiae, triacylglycerol mobilization for phospholipid synthesis occurs during growth resumption from stationary phase, and this metabolism is essential in the absence of de novo fatty acid synthesis. In this work, we provide evidence that DGK1-encoded diacylglycerol kinase activity is required to convert triacylglycerol-derived diacylglycerol to phosphatidate for phospholipid synthesis. Cells lacking diacylglycerol kinase activity (e.g. dgk1Δ mutation) failed to resume growth in the presence of the fatty acid synthesis inhibitor cerulenin. Lipid analysis data showed that dgk1Δ mutant cells did not mobilize triacylglycerol for membrane phospholipid synthesis and accumulated diacylglycerol. The dgk1Δ phenotypes were partially complemented by preventing the formation of diacylglycerol by the PAH1-encoded phosphatidate phosphatase and by channeling diacylglycerol to phosphatidylcholine via the Kennedy pathway. These observations, coupled to an inhibitory effect of dioctanoyl-diacylglycerol on the growth of wild type cells, indicated that diacylglycerol kinase also functions to alleviate diacylglycerol toxicity.
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Affiliation(s)
- Stylianos Fakas
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901, USA
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22
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Hein ND, Rainier SR, Richardson RJ, Fink JK. Motor neuron disease due to neuropathy target esterase mutation: enzyme analysis of fibroblasts from human subjects yields insights into pathogenesis. Toxicol Lett 2010; 199:1-5. [PMID: 20603202 DOI: 10.1016/j.toxlet.2010.06.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 06/24/2010] [Accepted: 06/25/2010] [Indexed: 11/25/2022]
Abstract
Recently, we identified neuropathy target esterase (NTE) mutation as the cause of an autosomal recessive motor neuron disease (NTE-MND). Subsequently, we showed that NTE-MND mutations reduced specific activity (SA) and altered inhibitory kinetics of NTE catalytic domain constructs. Recent preliminary results showed that NTE is expressed in cultured human skin fibroblasts, and others have used mutant forms of neuronal proteins expressed in fibroblasts as biomarkers of neurogenetic diseases. Therefore, the present study was carried out to test the hypothesis that NTE in cultured skin fibroblasts from NTE-MND subjects also exhibit altered enzymological properties assessed by SA and IC(50) values of mipafox (MIP) and chlorpyrifos oxon (CPO). NTE SA was reduced to 65% of control (wild-type NTE from commercially obtained fibroblasts) in homozygous M1012V fibroblasts and 59-61% of control in compound heterozygous R890H/c2946_2947InsCAGC fibroblasts. MIP IC(50) values were unaffected by the NTE mutations, but the CPO IC(50) increased 4.5-fold in homozygous M1012V fibroblasts. Interestingly, markedly reduced NTE SAs (40-43% of control) were observed in fibroblasts from asymptomatic subjects heterozygous for NTE insertion c2946_2947InsCAGC. This insertion is predicted to produce truncated NTE missing the last 235 residues of its catalytic domain. These observations confirm that NTE-MND mutations reduce NTE SA in vitro. Moreover, to the extent observations made in cultured fibroblasts may be generalized to events in the nervous system, lack of correlation between reduced fibroblast NTE SA and the occurrence of NTE-MND in NTE insertion mutation heterozygotes indicates that reduction of NTE SA alone is insufficient to cause MND.
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Affiliation(s)
- Nichole D Hein
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
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23
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Zhang M, Zhang Y, Giblin EM, Taylor DC. Ectopic expression of Arabidopsis phospholipase A genes elucidates role of phospholipase Bs in S. cerevisiae cells. Open Microbiol J 2009; 3:136-45. [PMID: 19707290 PMCID: PMC2731109 DOI: 10.2174/1874285800903010136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 07/21/2009] [Accepted: 07/24/2009] [Indexed: 11/22/2022] Open
Abstract
In S. cerevisiae neither disruption of the phospholipase B triple knockout mutant (plb1plb2plb3; plb123) nor over-expression of phospholipase Bs (PLBs) result in a phenotype different from wild type. In performing experiments to characterize candidate plant phospholipase (PLA) genes, we found, surprisingly, that ectopic expression of either of two different A. thaliana PLA2 or PLA1 genes in the yeast plb123 mutant completely inhibited cell growth. We proposed that while PLBs might not be essential for growth and metabolism of yeast cells, they may play an important role in cell survival by metabolizing excess intracellular lysophospholipids. To test our hypothesis, we overexpressed a plant phospholipase A2 (PLA2) in both WT and plb123 cells, producing a pool of lysophosphatidylcholine (lysoPtdCho) in both transformants. In 14C acetate labeling experiments, WT cells were able to catabolize the resultant labeled lysoPtdCho, preventing accumulation, and the cells grew normally. In contrast, in the triple plb123 mutant PLA2 transformant, lysoPtDCho accumulated more than 4-fold to a toxic level, inhibiting cell growth. However, this growth inhibition was complemented by co-expression of either PLB1, PLB2 or PLB3 in the plb123 triple mutant already expressing the plant PLA2. Furthermore, in labeling experiments, the rescued cells exhibited a 60-75% reduction in 14C-lysoPtdCho build-up compared to plb123PLA2 cells. Our data provides conclusive evidence that yeast PLBs can metabolize intracellular lysoPtdCho produced by plant PLA2 overexpression in yeast. Our experiments indicate the utility of ectopic plant phospholipase A gene expression to characterize poorly-understood phospholipid metabolism mutants in yeast or other organisms.
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Affiliation(s)
- Meng Zhang
- National Research Council of Canada, Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
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24
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Green P, Anyakoha N, Yadid G, Gispan-Herman I, Nicolaou A. Arachidonic acid-containing phosphatidylcholine species are increased in selected brain regions of a depressive animal model: implications for pathophysiology. Prostaglandins Leukot Essent Fatty Acids 2009; 80:213-20. [PMID: 19342208 DOI: 10.1016/j.plefa.2009.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 02/09/2009] [Accepted: 02/20/2009] [Indexed: 11/21/2022]
Abstract
The Flinders Sensitive Line (FSL) rat is a genetic animal model of depression. Following recent findings that the brain fatty acid composition of FSL is characterised by increased arachidonic acid (AA), we used electrospray tandem mass spectrometry and (1)H-NMR to examine lipid species in different brain areas. Cholesterol and sphingolipids were increased in the hypothalamus of the FSL rats. Furthermore, arachidonic acid-containing phosphatidylcholine (AA-PC) species were elevated with PC16:0/20:4, PC18:1/20:4 and PC18:0/20:4 (p<0.003) increased in the hypothalamus and striatum. In contrast, there was a decrease in some docosahexaenoic acid (DHA)-containing species, specifically PC18:1/22:6 (p<0.003) in the striatum and PE18:1/22:6 (p<0.004) in the prefrontal cortex. Since no significant differences were observed in the erythrocyte fatty acid concentrations, dietary or environmental causes for these observations are unlikely. The increase in AA-PC species which in this animal model may be associated with altered neuropathy target esterase activity, an enzyme involved in membrane PC homeostasis, may contribute to the depressive phenotype of the FSL rats.
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Affiliation(s)
- Pnina Green
- Laboratory for the Study of Fatty Acids, Felsenstein Medical Research Centre, Beilinson Campus, Sackler School of Medicine, Tel Aviv University, Petah Tiqwa 49100, Israel
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25
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Abstract
Phospholipid synthesis in the yeast Saccharomyces cerevisiae is a complex process that involves regulation by both genetic and biochemical mechanisms. The activity levels of phospholipid synthesis enzymes are controlled by gene expression (e.g., transcription) and by factors (lipids, water-soluble phospholipid precursors and products, and covalent modification of phosphorylation) that modulate catalysis. Phosphatidic acid, whose levels are controlled by the biochemical regulation of key phospholipid synthesis enzymes, plays a central role in the regulation of phospholipid synthesis gene expression.
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Affiliation(s)
- George M Carman
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA.
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27
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The yeast acylglycerol acyltransferase LCA1 is a key component of Lands cycle for phosphatidylcholine turnover. FEBS Lett 2007; 581:5511-6. [DOI: 10.1016/j.febslet.2007.10.061] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 10/28/2007] [Accepted: 10/31/2007] [Indexed: 11/23/2022]
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28
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Riekhof WR, Wu J, Gijón MA, Zarini S, Murphy RC, Voelker DR. Lysophosphatidylcholine metabolism in Saccharomyces cerevisiae: the role of P-type ATPases in transport and a broad specificity acyltransferase in acylation. J Biol Chem 2007; 282:36853-61. [PMID: 17951629 DOI: 10.1074/jbc.m706718200] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently described a new route for the synthesis of phosphatidylethanolamine (PtdEtn) from exogenous lyso-PtdEtn, which we have termed the exogenous lysolipid metabolism (ELM) pathway. The ELM pathway for lyso-PtdEtn requires the action of plasma membrane P-type ATPases Dnf1p and Dnf2p and their requisite beta-subunit, Lem3p, for the active uptake of lyso-PtdEtn. In addition, the acyl-CoA-dependent acyltransferase, Ale1p, mediates the acylation of the imported lysolipid to form PtdEtn. We now report that these components of the lyso-PtdEtn ELM pathway are also active with lyso-1-acyl-2-hydroxyl-sn-glycero-3-phosphocholine (PtdCho) as a substrate. Lyso-PtdCho supports the growth of a choline auxotrophic pem1Delta pem2Delta strain. Uptake of radiolabeled lyso-PtdCho was impaired by the dnf2Delta and lem3Delta mutations. Introduction of a lem3Delta mutation into a pem1Delta pem2Delta background impaired the ability of the resulting strain to grow with lyso-PtdCho as the sole precursor of PtdCho. After import of lyso-PtdCho, the recently characterized lyso-PtdEtn acyltransferase, Ale1p, functioned as the sole lyso-PtdCho acyltransferase in yeast. A pem1Delta pem2Delta ale1Delta strain grew with lyso-PtdCho as a substrate but showed a profound reduction in PtdCho content when lyso-PtdCho was the only precursor of PtdCho. Ale1p acylates lyso-PtdCho with a preference for monounsaturated acyl-CoA species, and the specific LPCAT activity of Ale1p in yeast membranes is >50-fold higher than the basal rate of de novo aminoglycerophospholipid biosynthesis from phosphatidylserine synthase activity. In addition to lyso-PtdCho, lyso-PtdEtn, and lyso-phosphatidic acid, Ale1p was also active with lysophosphatidylserine, lysophosphatidylglycerol, and lysophosphatidylinositol as substrates. These results establish a new pathway for the net synthesis of PtdCho in yeast and provide new tools for the study of PtdCho synthesis, transport, and remodeling.
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Affiliation(s)
- Wayne R Riekhof
- Department of Medicine, Program in Cell Biology, National Jewish Medical and Research Center, Denver, Colorado 80206, USA
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Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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