51
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Rahman MA, Mostofa MG, Ushimaru T. The Nem1/Spo7-Pah1/lipin axis is required for autophagy induction after TORC1 inactivation. FEBS J 2018; 285:1840-1860. [PMID: 29604183 DOI: 10.1111/febs.14448] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/01/2018] [Accepted: 03/26/2018] [Indexed: 02/06/2023]
Abstract
Autophagy is a process that requires intense membrane remodeling and consumption. The nutrient-responsive TORC1 (target of rapamycin complex 1) kinase regulates autophagy. However, how TORC1 controls autophagy via lipid/membrane biogenesis is unknown. TORC1 regulates the function of yeast phosphatidate phosphatase lipin Pah1 via the Nem1/Spo7 phosphatase complex. Here, we show that the Nem1/Spo7-Pah1 axis is required for autophagy induction after TORC1 inactivation and survival during starvation. Furthermore, this axis was critical for nucleophagy (both micronucleophagy and macronucleophagy) and was required for proper localization of micronucleophagy factor Nvj1 and macronucleophagy receptor Atg39. This study indicated that the Nem1/Spo7-Pah1 axis controlled by TORC1 is a critical branch for autophagy induction in nutrient starvation conditions.
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Affiliation(s)
| | - Md Golam Mostofa
- Graduate School of Science and Technology, Shizuoka University, Japan
| | - Takashi Ushimaru
- Graduate School of Science and Technology, Shizuoka University, Japan.,Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Japan
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52
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Zhang Z, He G, Han GS, Zhang J, Catanzaro N, Diaz A, Wu Z, Carman GM, Xie L, Wang X. Host Pah1p phosphatidate phosphatase limits viral replication by regulating phospholipid synthesis. PLoS Pathog 2018; 14:e1006988. [PMID: 29649282 PMCID: PMC5916857 DOI: 10.1371/journal.ppat.1006988] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/24/2018] [Accepted: 03/24/2018] [Indexed: 11/20/2022] Open
Abstract
Replication of positive-strand RNA viruses [(+)RNA viruses] takes place in membrane-bound viral replication complexes (VRCs). Formation of VRCs requires virus-mediated manipulation of cellular lipid synthesis. Here, we report significantly enhanced brome mosaic virus (BMV) replication and much improved cell growth in yeast cells lacking PAH1 (pah1Δ), the sole yeast ortholog of human LIPIN genes. PAH1 encodes Pah1p (phosphatidic acid phosphohydrolase), which converts phosphatidate (PA) to diacylglycerol that is subsequently used for the synthesis of the storage lipid triacylglycerol. Inactivation of Pah1p leads to altered lipid composition, including high levels of PA, total phospholipids, ergosterol ester, and free fatty acids, as well as expansion of the nuclear membrane. In pah1Δ cells, BMV replication protein 1a and double-stranded RNA localized to the extended nuclear membrane, there was a significant increase in the number of VRCs formed, and BMV genomic replication increased by 2-fold compared to wild-type cells. In another yeast mutant that lacks both PAH1 and DGK1 (encodes diacylglycerol kinase converting diacylglycerol to PA), which has a normal nuclear membrane but maintains similar lipid compositional changes as in pah1Δ cells, BMV replicated as efficiently as in pah1Δ cells, suggesting that the altered lipid composition was responsible for the enhanced BMV replication. We further showed that increased levels of total phospholipids play an important role because the enhanced BMV replication required active synthesis of phosphatidylcholine, the major membrane phospholipid. Moreover, overexpression of a phosphatidylcholine synthesis gene (CHO2) promoted BMV replication. Conversely, overexpression of PAH1 or plant PAH1 orthologs inhibited BMV replication in yeast or Nicotiana benthamiana plants. Competing with its host for limited resources, BMV inhibited host growth, which was markedly alleviated in pah1Δ cells. Our work suggests that Pah1p promotes storage lipid synthesis and thus represses phospholipid synthesis, which in turn restricts both viral replication and cell growth during viral infection.
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Affiliation(s)
- Zhenlu Zhang
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Guijuan He
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - 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, United States of America
| | - Jiantao Zhang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Nicholas Catanzaro
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States of America
| | - Arturo Diaz
- Department of Biology, La Sierra University, Riverside, VA, United States of America
| | - Zujian Wu
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - 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, United States of America
| | - Lianhui Xie
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - Xiaofeng Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
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53
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DeBose-Boyd RA, Ye J. SREBPs in Lipid Metabolism, Insulin Signaling, and Beyond. Trends Biochem Sci 2018; 43:358-368. [PMID: 29500098 DOI: 10.1016/j.tibs.2018.01.005] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/08/2018] [Accepted: 01/10/2018] [Indexed: 12/22/2022]
Abstract
Sterol regulatory element-binding proteins (SREBPs) are a family of membrane-bound transcription factors that activate genes encoding enzymes required for synthesis of cholesterol and unsaturated fatty acids. SREBPs are controlled by multiple mechanisms at the level of mRNA synthesis, proteolytic activation, and transcriptional activity. In this review, we summarize the recent findings that contribute to the current understanding of the regulation of SREBPs and their physiologic roles in maintenance of lipid homeostasis, insulin signaling, innate immunity, and cancer development.
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Affiliation(s)
- Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9046, USA.
| | - Jin Ye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9046, USA.
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54
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Park Y, Han GS, Carman GM. A conserved tryptophan within the WRDPLVDID domain of yeast Pah1 phosphatidate phosphatase is required for its in vivo function in lipid metabolism. J Biol Chem 2017; 292:19580-19589. [PMID: 29066621 PMCID: PMC5712600 DOI: 10.1074/jbc.m117.819375] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/17/2017] [Indexed: 11/06/2022] Open
Abstract
PAH1-encoded phosphatidate phosphatase, which catalyzes the dephosphorylation of phosphatidate to produce diacylglycerol at the endoplasmic reticulum membrane, plays a major role in controlling the utilization of phosphatidate for the synthesis of triacylglycerol or membrane phospholipids. The conserved N-LIP and haloacid dehalogenase-like domains of Pah1 are required for phosphatidate phosphatase activity and the in vivo function of the enzyme. Its non-conserved regions, which are located between the conserved domains and at the C terminus, contain sites for phosphorylation by multiple protein kinases. Truncation analyses of the non-conserved regions showed that they are not essential for the catalytic activity of Pah1 and its physiological functions (e.g. triacylglycerol synthesis). This analysis also revealed that the C-terminal region contains a previously unrecognized WRDPLVDID domain (residues 637-645) that is conserved in yeast, mice, and humans. The deletion of this domain had no effect on the catalytic activity of Pah1 but caused the loss of its in vivo function. Site-specific mutational analyses of the conserved residues within WRDPLVDID indicated that Trp-637 plays a crucial role in Pah1 function. This work also demonstrated that the catalytic activity of Pah1 is required but is not sufficient for its in vivo functions.
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Affiliation(s)
- Yeonhee Park
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
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55
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Cho JH, Han JS. Phospholipase D and Its Essential Role in Cancer. Mol Cells 2017; 40:805-813. [PMID: 29145720 PMCID: PMC5712509 DOI: 10.14348/molcells.2017.0241] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/16/2017] [Accepted: 11/11/2017] [Indexed: 11/27/2022] Open
Abstract
The role of phospholipase D (PLD) in cancer development and management has been a major area of interest for researchers. The purpose of this mini-review is to explore PLD and its distinct role during chemotherapy including anti-apoptotic function. PLD is an enzyme that belongs to the phospholipase super family and is found in a broad range of organisms such as viruses, yeast, bacteria, animals, and plants. The function and activity of PLD are widely dependent on and regulated by neurotransmitters, hormones, small monomeric GTPases, and lipids. A growing body of research has shown that PLD activity is significantly increased in cancer tissues and cells, indicating that it plays a critical role in signal transduction, cell proliferation, and anti-apoptotic processes. In addition, recent studies show that PLD is a downstream transcriptional target of proteins that contribute to inflammation and carcinogenesis such as Sp1, NFκB, TCF4, ATF-2, NFATc2, and EWS-Fli. Thus, compounds that inhibit expression or activity of PLD in cells can be potentially useful in reducing inflammation and sensitizing resistant cancers during chemotherapy.
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Affiliation(s)
- Ju Hwan Cho
- Arthur G. James Cancer Hospital Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 4321,
USA
| | - Joong-Soo Han
- Biomedical Research Institute and Department of Biochemistry & Molecular Biology, College of Medicine, Hanyang University, Seoul 04763,
Korea
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56
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Jacquemyn J, Cascalho A, Goodchild RE. The ins and outs of endoplasmic reticulum-controlled lipid biosynthesis. EMBO Rep 2017; 18:1905-1921. [PMID: 29074503 DOI: 10.15252/embr.201643426] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 08/18/2017] [Accepted: 09/18/2017] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER)-localized enzymes synthesize the vast majority of cellular lipids. The ER therefore has a major influence on cellular lipid biomass and balances the production of different lipid categories, classes, and species. Signals from outside and inside the cell are directed to ER-localized enzymes, and lipid enzyme activities are defined by the integration of internal, homeostatic, and external information. This allows ER-localized lipid synthesis to provide the cell with membrane lipids for growth, proliferation, and differentiation-based changes in morphology and structure, and to maintain membrane homeostasis across the cell. ER enzymes also respond to physiological signals to drive carbohydrates and nutritionally derived lipids into energy-storing triglycerides. In this review, we highlight some key regulatory mechanisms that control ER-localized enzyme activities in animal cells. We also discuss how they act in concert to maintain cellular lipid homeostasis, as well as how their dysregulation contributes to human disease.
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Affiliation(s)
- Julie Jacquemyn
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ana Cascalho
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Rose E Goodchild
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium .,Department of Neurosciences, KU Leuven, Leuven, Belgium
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57
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Wang H, Airola MV, Reue K. How lipid droplets "TAG" along: Glycerolipid synthetic enzymes and lipid storage. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1131-1145. [PMID: 28642195 PMCID: PMC5688854 DOI: 10.1016/j.bbalip.2017.06.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/15/2017] [Accepted: 06/15/2017] [Indexed: 02/06/2023]
Abstract
Triacylglycerols (TAG) serve as the predominant form of energy storage in mammalian cells, and TAG synthesis influences conditions such as obesity, fatty liver, and insulin resistance. In most tissues, the glycerol 3-phosphate pathway enzymes are responsible for TAG synthesis, and the regulation and function of these enzymes is therefore important for metabolic homeostasis. Here we review the sites and regulation of glycerol-3-phosphate acyltransferase (GPAT), acylglycerol-3-phosphate acyltransferase (AGPAT), lipin phosphatidic acid phosphatase (PAP), and diacylglycerol acyltransferase (DGAT) enzyme action. We highlight the critical roles that these enzymes play in human health by reviewing Mendelian disorders that result from mutation in the corresponding genes. We also summarize the valuable insights that genetically engineered mouse models have provided into the cellular and physiological roles of GPATs, AGPATs, lipins and DGATs. Finally, we comment on the status and feasibility of therapeutic approaches to metabolic disease that target enzymes of the glycerol 3-phosphate pathway. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Huan Wang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Michael V Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, CA, United States.
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58
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Adachi Y, Itoh K, Yamada T, Cerveny KL, Suzuki TL, Macdonald P, Frohman MA, Ramachandran R, Iijima M, Sesaki H. Coincident Phosphatidic Acid Interaction Restrains Drp1 in Mitochondrial Division. Mol Cell 2017; 63:1034-43. [PMID: 27635761 DOI: 10.1016/j.molcel.2016.08.013] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/20/2016] [Accepted: 08/09/2016] [Indexed: 12/31/2022]
Abstract
Mitochondria divide to control their size, distribution, turnover, and function. Dynamin-related protein 1 (Drp1) is a critical mechanochemical GTPase that drives constriction during mitochondrial division. It is generally believed that mitochondrial division is regulated during recruitment of Drp1 to mitochondria and its oligomerization into a division apparatus. Here, we report an unforeseen mechanism that regulates mitochondrial division by coincident interactions of Drp1 with the head group and acyl chains of phospholipids. Drp1 recognizes the head group of phosphatidic acid (PA) and two saturated acyl chains of another phospholipid by penetrating into the hydrophobic core of the membrane. The dual phospholipid interactions restrain Drp1 via inhibition of oligomerization-stimulated GTP hydrolysis that promotes membrane constriction. Moreover, a PA-producing phospholipase, MitoPLD, binds Drp1, creating a PA-rich microenvironment in the vicinity of a division apparatus. Thus, PA controls the activation of Drp1 after the formation of the division apparatus.
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Affiliation(s)
- Yoshihiro Adachi
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kie Itoh
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Tatsuya Yamada
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kara L Cerveny
- Department of Biology, Reed College, Portland, OR 97202, USA
| | - Takamichi L Suzuki
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Patrick Macdonald
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Michael A Frohman
- Department of Pharmacological Sciences and Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Miho Iijima
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
| | - Hiromi Sesaki
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
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59
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Zhang P, Reue K. Lipin proteins and glycerolipid metabolism: Roles at the ER membrane and beyond. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:1583-1595. [PMID: 28411173 PMCID: PMC5688847 DOI: 10.1016/j.bbamem.2017.04.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/29/2017] [Accepted: 04/09/2017] [Indexed: 01/09/2023]
Abstract
The regulation of glycerolipid biosynthesis is critical for homeostasis of cellular lipid stores and membranes. Here we review the role of lipin phosphatidic acid phosphatase enzymes in glycerolipid synthesis. Lipin proteins are unique among glycerolipid biosynthetic enzymes in their ability to transit among cellular membranes, rather than remain membrane tethered. We focus on the mechanisms that underlie lipin protein interactions with membranes and the versatile roles of lipins in several organelles, including the endoplasmic reticulum, mitochondria, endolysosomes, lipid droplets, and nucleus. We also review the corresponding physiological roles of lipins, which have been uncovered by the study of genetic lipin deficiencies. We propose that the growing body of knowledge concerning the biochemical and cellular activities of lipin proteins will be valuable for understanding the physiological functions of lipin proteins in health and disease. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Peixiang Zhang
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States
| | - Karen Reue
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States; Molecular Biology Institute, University of California, Los Angeles, United States.
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60
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Lipid droplet growth and adipocyte development: mechanistically distinct processes connected by phospholipids. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1273-1283. [PMID: 28668300 DOI: 10.1016/j.bbalip.2017.06.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/20/2017] [Accepted: 06/23/2017] [Indexed: 12/19/2022]
Abstract
The differentiation of preadipocytes into mature adipocytes is accompanied by the growth and formation of a giant, unilocular lipid droplet (LD). Mechanistically however, LD growth and adipogenesis are two different processes. Recent studies have uncovered a number of proteins that are able to regulate both LD dynamics and adipogenesis, such as SEIPIN, LIPIN and CDP-Diacylglycerol Synthases. It appears that phospholipids, phosphatidic acid in particular, play a critical role in both LD budding/growth and adipocyte development. This review summarizes recent advances, and aims to provide a better understanding of LD growth as well as adipogenesis, two critical aspects in mammalian fat storage. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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61
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Li J, Chen Y, Chen Z, He A, Xie H, Zhang Q, Cai Z, Liu Y, Huang W. SPRY4-IT1: A novel oncogenic long non-coding RNA in human cancers. Tumour Biol 2017; 39:1010428317711406. [PMID: 28651500 DOI: 10.1177/1010428317711406] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Long non-coding RNAs are classified as a kind of RNA, which are longer than 200 nucleotides in length and cannot be translated into proteins. Multiple studies have demonstrated that long non-coding RNAs are involved in various cellular processes, including proliferation, differentiation, cell death, and metastasis. Among numerous long non-coding RNAs, we focus on Sprouty4-Intron 1 (SPRY4-IT1), a well-known long non-coding RNA that is overexpressed in various kinds of tumor tissues and cell lines. Accumulating evidences show that SPRY4-IT1 was dysregulated in various cancers, including melanoma, breast cancer, esophageal squamous cell carcinoma, non-small cell lung cancer, gastric cancer, colon cancer, and hepatocellular carcinoma, and amplification of SPRY4-IT1 was associated with different clinicopathological features of cancer patients. Importantly, SPRY4-IT1 exerts important roles in tumor progression and metastasis. However, detailed molecular mechanisms of SPRY4-IT1 in cancer progression and metastasis were poorly understood. In this review, we have focused on the characteristics of SPRY4-IT1 and illustrated the biological function and mechanism of SPRY4-IT1 in cancer development.
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Affiliation(s)
- Jianfa Li
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
- 2 Shantou University Medical College, Shantou, People's Republic of China
| | - Yincong Chen
- 2 Shantou University Medical College, Shantou, People's Republic of China
| | - Zhicong Chen
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
- 2 Shantou University Medical College, Shantou, People's Republic of China
| | - Anbang He
- 2 Shantou University Medical College, Shantou, People's Republic of China
- 3 Anhui Medical University, Hefei, People's Republic of China
| | - Haibiao Xie
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
- 2 Shantou University Medical College, Shantou, People's Republic of China
| | - Qiaoxiao Zhang
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
| | - Zhiming Cai
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
- 2 Shantou University Medical College, Shantou, People's Republic of China
- 3 Anhui Medical University, Hefei, People's Republic of China
| | - Yuchen Liu
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
| | - Weiren Huang
- 1 Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, People's Republic of China
- 2 Shantou University Medical College, Shantou, People's Republic of China
- 3 Anhui Medical University, Hefei, People's Republic of China
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62
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Silva SF, Levy D, Ruiz JLM, de Melo TC, Isaac C, Fidelis ML, Rodrigues A, Bydlowski SP. Oxysterols in adipose tissue-derived mesenchymal stem cell proliferation and death. J Steroid Biochem Mol Biol 2017; 169:164-175. [PMID: 27133385 DOI: 10.1016/j.jsbmb.2016.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/22/2016] [Accepted: 04/27/2016] [Indexed: 11/26/2022]
Abstract
Mesenchymal stem cells (MSCs) are multipotent cells characterized by self-renewal and cellular differentiation capabilities. Oxysterols comprise a very heterogeneous group derived from cholesterol through enzymatic and non-enzymatic oxidation. Potent effects in cell death processes, including cytoxicity and apoptosis induction, were described in several cell lines. Very little is known about the effects of oxysterols in MSCs. 7-ketocholesterol (7-KC), one of the most important oxysterols, was shown to be cytotoxic to human adipose tissue-derived MSCs. Here, we describe the short-term (24h) cytotoxic effects of cholestan-3α-5β-6α-triol, 3,5 cholestan-7-one, (3α-5β-6α)- cholestane-3,6-diol, 7-oxocholest-5-en-3β-yl acetate, and 5β-6β epoxy-cholesterol, on MSCs derived from human adipose tissue. MSCs were isolated from adipose tissue obtained from three young, healthy women. Oxysterols, with the exception of 3,5 cholestan-7-one and 7-oxocholest-5-en-3β-yl acetate, led to a complex mode of cell death that include apoptosis, necrosis and autophagy, depending on the type of oxysterol and concentration, being cholestan-3α-5β-6α-triol the most effective. Inhibition of proliferation was also promoted by these oxysterols, but no changes in cell cycle were observed.
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Affiliation(s)
- Suelen Feitoza Silva
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av.Dr.Enéas de Carvalho Aguiar, 155, 1st floor, room 43, 05403-000, São Paulo/SP, Brazil
| | - Débora Levy
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av.Dr.Enéas de Carvalho Aguiar, 155, 1st floor, room 43, 05403-000, São Paulo/SP, Brazil
| | - Jorge Luis Maria Ruiz
- Federal University of Latin American Integration-UNILA, Life and Nature Science Institute, Av. Tarquinio Joslin dos Santos, 1000, Sala 105, CEP: 85870-901, Foz do Iguacu, Parana/PR, Brazil
| | - Thatiana Correa de Melo
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av.Dr.Enéas de Carvalho Aguiar, 155, 1st floor, room 43, 05403-000, São Paulo/SP, Brazil
| | - Cesar Isaac
- Cell Culture and Wound Healing Research Laboratory, Division of Plastic Surgery, Hospital das Clínicas, University of São Paulo Medical School, Av. Dr. Arnaldo, 455, 1st floor, 05403-000, São Paulo/SP, Brazil
| | - Maíra Luísa Fidelis
- Department of Earth and Exact Sciences, Federal University of São Paulo, São Paulo/SP, Brazil
| | - Alessandro Rodrigues
- Department of Earth and Exact Sciences, Federal University of São Paulo, São Paulo/SP, Brazil
| | - Sérgio Paulo Bydlowski
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av.Dr.Enéas de Carvalho Aguiar, 155, 1st floor, room 43, 05403-000, São Paulo/SP, Brazil.
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63
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The Lipid Droplet and the Endoplasmic Reticulum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:111-120. [DOI: 10.1007/978-981-10-4567-7_8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Cascalho A, Jacquemyn J, Goodchild RE. Membrane defects and genetic redundancy: Are we at a turning point for DYT1 dystonia? Mov Disord 2016; 32:371-381. [PMID: 27911022 DOI: 10.1002/mds.26880] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/24/2016] [Accepted: 10/29/2016] [Indexed: 12/11/2022] Open
Abstract
Heterozygosity for a 3-base pair deletion (ΔGAG) in TOR1A/torsinA is one of the most common causes of hereditary dystonia. In this review, we highlight current understanding of how this mutation causes disease from research spanning structural biochemistry, cell science, neurobiology, and several model organisms. We now know that homozygosity for ΔGAG has the same effects as Tor1aKO , implicating a partial loss of function mechanism in the ΔGAG/+ disease state. In addition, torsinA loss specifically affects neurons in mice, even though the gene is broadly expressed, apparently because of differential expression of homologous torsinB. Furthermore, certain neuronal subtypes are more severely affected by torsinA loss. Interestingly, these include striatal cholinergic interneurons that display abnormal responses to dopamine in several Tor1a animal models. There is also progress on understanding torsinA molecular cell biology. The structural basis of how ΔGAG inhibits torsinA ATPase activity is defined, although mutant torsinAΔGAG protein also displays some characteristics suggesting it contributes to dystonia by a gain-of-function mechanism. Furthermore, a consistent relationship is emerging between torsin dysfunction and membrane biology, including an evolutionarily conserved regulation of lipid metabolism. Considered together, these findings provide major advances toward understanding the molecular, cellular, and neurobiological pathologies of DYT1/TOR1A dystonia that can hopefully be exploited for new approaches to treat this disease. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Ana Cascalho
- Vlaams Instituut voor Biotechnologie Centre for the Biology of Disease, Leuven, Belgium.,KU Leuven, Department of Human Genetics, Leuven, Belgium
| | - Julie Jacquemyn
- Vlaams Instituut voor Biotechnologie Centre for the Biology of Disease, Leuven, Belgium.,KU Leuven, Department of Human Genetics, Leuven, Belgium
| | - Rose E Goodchild
- Vlaams Instituut voor Biotechnologie Centre for the Biology of Disease, Leuven, Belgium.,KU Leuven, Department of Human Genetics, Leuven, Belgium
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65
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Kim JY, Kim G, Lim SC, Choi HS. LPIN1 promotes epithelial cell transformation and mammary tumourigenesis via enhancing insulin receptor substrate 1 stability. Carcinogenesis 2016; 37:1199-1209. [PMID: 27729374 DOI: 10.1093/carcin/bgw104] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/25/2016] [Accepted: 10/10/2016] [Indexed: 02/07/2023] Open
Abstract
LPIN1 is a protein that exhibits dual functions as a phosphatidic acid phosphatase enzyme in regulation of triglyceride and glycerophospholipid metabolism and a transcriptional coregulator. Through unknown tumour-promoting mechanism, LPIN1 frequently observed in various human cancer cell lines controls main cellular processes involved in cancer progression. Here, we demonstrate that LPIN1 enhances the tumour-promoting function of insulin receptor substrate 1 (IRS1) by controlling IRS1 stability. LPIN1 interacts with IRS1 in an insulin growth factor-1-dependent signalling pathway and inhibits its serine phosphorylation, and thereby eliminating ubiquitin-dependent degradation of IRS1 via proteasomal and lysosomal pathways. Consequently, LPIN1 overexpression increases IRS1 abundance and enhances IRS1's ability to induce epithelial cell proliferation and mammary tumourigenesis. By contrast, depletion or inhibition of LPIN1 in breast cancer cells leads to a decreased IRS1 level, which subsequently inhibits the RAF1-mediated signalling pathway and AP-1 activity. In the syngeneic 4T1 breast cancer model, LPIN1 overexpression increased tumour development, whereas inhibition of LPIN1 and IRS1 suppressed it. Consistent with these observations, LPIN1 levels were positively correlated with IRS1 expression in human breast cancer. Thus, our results indicate a mechanism by which IRS1 expression is increased in breast cancer, and LPIN1 may be a promising drug target for anticancer therapy.
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Affiliation(s)
| | | | - Sung-Chul Lim
- Department of Pathology, School of Medicine, Chosun University, 309 Philmundaero, Dong-gu, Gwangju 61452, Republic of Korea
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66
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Grillet M, Dominguez Gonzalez B, Sicart A, Pöttler M, Cascalho A, Billion K, Hernandez Diaz S, Swerts J, Naismith TV, Gounko NV, Verstreken P, Hanson PI, Goodchild RE. Torsins Are Essential Regulators of Cellular Lipid Metabolism. Dev Cell 2016; 38:235-47. [PMID: 27453503 DOI: 10.1016/j.devcel.2016.06.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/18/2016] [Accepted: 06/12/2016] [Indexed: 01/10/2023]
Abstract
Torsins are developmentally essential AAA+ proteins, and mutation of human torsinA causes the neurological disease DYT1 dystonia. They localize in the ER membranes, but their cellular function remains unclear. We now show that dTorsin is required in Drosophila adipose tissue, where it suppresses triglyceride levels, promotes cell growth, and elevates membrane lipid content. We also see that human torsinA at the inner nuclear membrane is associated with membrane expansion and elevated cellular lipid content. Furthermore, the key lipid metabolizing enzyme, lipin, is mislocalized in dTorsin-KO cells, and dTorsin increases levels of the lipin substrate, phosphatidate, and reduces the product, diacylglycerol. Finally, genetic suppression of dLipin rescues dTorsin-KO defects, including adipose cell size, animal growth, and survival. These findings identify that torsins are essential regulators of cellular lipid metabolism and implicate disturbed lipid biology in childhood-onset DYT1 dystonia.
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Affiliation(s)
- Micheline Grillet
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Beatriz Dominguez Gonzalez
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Adria Sicart
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Maria Pöttler
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Ana Cascalho
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Karolien Billion
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Sergio Hernandez Diaz
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Jef Swerts
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Teresa V Naismith
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Natalia V Gounko
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Electron Microscopy Platform, VIB Bio-Imaging Core, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Patrik Verstreken
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Phyllis I Hanson
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Rose E Goodchild
- VIB Centre for the Biology of Disease, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium; Department of Human Genetics, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium.
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67
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Hsieh LS, Su WM, Han GS, Carman GM. Phosphorylation of Yeast Pah1 Phosphatidate Phosphatase by Casein Kinase II Regulates Its Function in Lipid Metabolism. J Biol Chem 2016; 291:9974-90. [PMID: 27044741 DOI: 10.1074/jbc.m116.726588] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Indexed: 12/14/2022] Open
Abstract
Pah1 phosphatidate phosphatase in Saccharomyces cerevisiae catalyzes the penultimate step in the synthesis of triacylglycerol (i.e. the production of diacylglycerol by dephosphorylation of phosphatidate). The enzyme playing a major role in lipid metabolism is subject to phosphorylation (e.g. by Pho85-Pho80, Cdc28-cyclin B, and protein kinases A and C) and dephosphorylation (e.g. by Nem1-Spo7) that regulate its cellular location, catalytic activity, and stability/degradation. In this work, we show that Pah1 is a substrate for casein kinase II (CKII); its phosphorylation was time- and dose-dependent and was dependent on the concentrations of Pah1 (Km = 0.23 μm) and ATP (Km = 5.5 μm). By mass spectrometry, truncation analysis, site-directed mutagenesis, phosphopeptide mapping, and phosphoamino acid analysis, we identified that >90% of its phosphorylation occurs on Thr-170, Ser-250, Ser-313, Ser-705, Ser-814, and Ser-818. The CKII-phosphorylated Pah1 was a substrate for the Nem1-Spo7 protein phosphatase and was degraded by the 20S proteasome. The prephosphorylation of Pah1 by protein kinase A or protein kinase C reduced its subsequent phosphorylation by CKII. The prephosphorylation of Pah1 by CKII reduced its subsequent phosphorylation by protein kinase A but not by protein kinase C. The expression of Pah1 with combined mutations of S705D and 7A, which mimic its phosphorylation by CKII and lack of phosphorylation by Pho85-Pho80, caused an increase in triacylglycerol content and lipid droplet number in cells expressing the Nem1-Spo7 phosphatase complex.
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Affiliation(s)
- Lu-Sheng Hsieh
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Wen-Min Su
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
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68
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Heier C, Haemmerle G. Fat in the heart: The enzymatic machinery regulating cardiac triacylglycerol metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1500-12. [PMID: 26924251 DOI: 10.1016/j.bbalip.2016.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 01/22/2023]
Abstract
The heart predominantly utilizes fatty acids (FAs) as energy substrate. FAs that enter cardiomyocytes can be activated and directly oxidized within mitochondria (and peroxisomes) or they can be esterified and intracellularly deposited as triacylglycerol (TAG) often simply referred to as fat. An increase in cardiac TAG can be a signature of the diseased heart and may implicate a minor role of TAG synthesis and breakdown in normal cardiac energy metabolism. Often overlooked, the heart has an extremely high TAG turnover and the transient deposition of FAs within the cardiac TAG pool critically determines the availability of FAs as energy substrate and signaling molecules. We herein review the recent literature regarding the enzymes and co-regulators involved in cardiomyocyte TAG synthesis and catabolism and discuss the interconnection of these metabolic pathways in the normal and diseased heart. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Affiliation(s)
- Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Austria
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69
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Lipid droplets, lipophagy, and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:793-805. [PMID: 26713677 DOI: 10.1016/j.bbalip.2015.12.010] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/06/2015] [Accepted: 12/17/2015] [Indexed: 02/06/2023]
Abstract
Lipids are essential components for life. Their various structural and physical properties influence diverse cellular processes and, thereby, human health. Lipids are not genetically encoded but are synthesized and modified by complex metabolic pathways, supplying energy, membranes, signaling molecules, and hormones to affect growth, physiology, and response to environmental insults. Lipid homeostasis is crucial, such that excess fatty acids (FAs) can be harmful to cells. To prevent such lipotoxicity, cells convert excess FAs into neutral lipids for storage in organelles called lipid droplets (LDs). These organelles do not simply manage lipid storage and metabolism but also are involved in protein quality management, pathogenesis, immune responses, and, potentially, neurodegeneration. In recent years, a major trend in LD biology has centered around the physiology of lipid mobilization via lipophagy of fat stored within LDs. This review summarizes key findings in LD biology and lipophagy, offering novel insights into this rapidly growing field. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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70
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Chae M, Jung JY, Bae IH, Kim HJ, Lee TR, Shin DW. Lipin-1 expression is critical for keratinocyte differentiation. J Lipid Res 2015; 57:563-73. [PMID: 26658689 DOI: 10.1194/jlr.m062588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Indexed: 12/19/2022] Open
Abstract
Lipin-1 is an Mg(2+)-dependent phosphatidate phosphatase that facilitates the dephosphorylation of phosphatidic acid to generate diacylglycerol. Little is known about the expression and function of lipin-1 in normal human epidermal keratinocytes (NHEKs). Here, we demonstrate that lipin-1 is present in basal and spinous layers of the normal human epidermis, and lipin-1 expression is gradually downregulated during NHEK differentiation. Interestingly, lipin-1 knockdown (KD) inhibited keratinocyte differentiation and caused G1 arrest by upregulating p21 expression. Cell cycle arrest by p21 is required for commitment of keratinocytes to differentiation, but must be downregulated for the progress of keratinocyte differentiation. Therefore, reduced keratinocyte differentiation results from sustained upregulation of p21 by lipin-1 KD. Lipin-1 KD also decreased the phosphorylation/activation of protein kinase C (PKC)α, whereas lipin-1 overexpression increased PKCα phosphorylation. Treatment with PKCα inhibitors, like lipin-1 KD, stimulated p21 expression, while lipin-1 overexpression reduced p21 expression, implicating PKCα in lipin-1-induced regulation of p21 expression. Taken together, these results suggest that lipin-1-mediated downregulation of p21 is critical for the progress of keratinocyte differentiation after the initial commitment of keratinocytes to differentiation induced by p21, and that PKCα is involved in p21 expression regulation by lipin-1.
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Affiliation(s)
- Minjung Chae
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Ji-Yong Jung
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Il-Hong Bae
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Hyoung-June Kim
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Tae Ryong Lee
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Dong Wook Shin
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
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71
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Meijer IA, Sasarman F, Maftei C, Rossignol E, Vanasse M, Major P, Mitchell GA, Brunel-Guitton C. LPIN1 deficiency with severe recurrent rhabdomyolysis and persistent elevation of creatine kinase levels due to chromosome 2 maternal isodisomy. Mol Genet Metab Rep 2015. [PMID: 28649549 PMCID: PMC5471397 DOI: 10.1016/j.ymgmr.2015.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Fatty acid oxidation disorders and lipin-1 deficiency are the commonest genetic causes of rhabdomyolysis in children. We describe a lipin-1-deficient boy with recurrent, severe rhabdomyolytic episodes from the age of 4 years. Analysis of the LPIN1 gene that encodes lipin-1 revealed a novel homozygous frameshift mutation in exon 9, c.1381delC (p.Leu461SerfsX47), and complete uniparental isodisomy of maternal chromosome 2. This mutation is predicted to cause complete lipin-1 deficiency. The patient had six rhabdomyolytic crises, with creatine kinase (CK) levels up to 300,000 U/L (normal, 30 to 200). Plasma CK remained elevated between crises. A treatment protocol was instituted, with early aggressive monitoring, hydration, electrolyte replacement and high caloric, high carbohydrate intake. The patient received dexamethasone during two crises, which was well-tolerated and in these episodes, peak CK values were lower than in preceding episodes. Studies of anti-inflammatory therapy may be indicated in lipin-1 deficiency.
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Affiliation(s)
- I A Meijer
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - F Sasarman
- Division of Biochemical Genetics Laboratory, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - C Maftei
- Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - E Rossignol
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - M Vanasse
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - P Major
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - G A Mitchell
- Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - C Brunel-Guitton
- Division of Biochemical Genetics Laboratory, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada.,Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
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72
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Barbosa AD, Sembongi H, Su WM, Abreu S, Reggiori F, Carman GM, Siniossoglou S. Lipid partitioning at the nuclear envelope controls membrane biogenesis. Mol Biol Cell 2015; 26:3641-57. [PMID: 26269581 PMCID: PMC4603934 DOI: 10.1091/mbc.e15-03-0173] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/22/2015] [Accepted: 08/06/2015] [Indexed: 12/11/2022] Open
Abstract
Partitioning of lipid precursors between membranes and storage is crucial for cell growth, and its disruption underlies pathologies such as cancer, obesity, and type 2 diabetes. However, the mechanisms and signals that regulate this process are largely unknown. In yeast, lipid precursors are mainly used for phospholipid synthesis in nutrient-rich conditions in order to sustain rapid proliferation but are redirected to triacylglycerol (TAG) stored in lipid droplets during starvation. Here we investigate how cells reprogram lipid metabolism in the endoplasmic reticulum. We show that the conserved phosphatidate (PA) phosphatase Pah1, which generates diacylglycerol from PA, targets a nuclear membrane subdomain that is in contact with growing lipid droplets and mediates TAG synthesis. We find that cytosol acidification activates the master regulator of Pah1, the Nem1-Spo7 complex, thus linking Pah1 activity to cellular metabolic status. In the absence of TAG storage capacity, Pah1 still binds the nuclear membrane, but lipid precursors are redirected toward phospholipids, resulting in nuclear deformation and a proliferation of endoplasmic reticulum membrane. We propose that, in response to growth signals, activation of Pah1 at the nuclear envelope acts as a switch to control the balance between membrane biogenesis and lipid storage.
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Affiliation(s)
- Antonio Daniel Barbosa
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Hiroshi Sembongi
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Wen-Min Su
- 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
| | - Susana Abreu
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, 9713 A Groningen, Netherlands
| | - Fulvio Reggiori
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, 9713 A Groningen, Netherlands
| | - 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
| | - Symeon Siniossoglou
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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73
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Park Y, Han GS, Mileykovskaya E, Garrett TA, Carman GM. Altered Lipid Synthesis by Lack of Yeast Pah1 Phosphatidate Phosphatase Reduces Chronological Life Span. J Biol Chem 2015; 290:25382-94. [PMID: 26338708 DOI: 10.1074/jbc.m115.680314] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Indexed: 01/20/2023] Open
Abstract
In Saccharomyces cerevisiae, Pah1 phosphatidate phosphatase, which catalyzes the dephosphorylation of phosphatidate to yield diacylglycerol, plays a crucial role in the synthesis of the storage lipid triacylglycerol. This evolutionarily conserved enzyme also plays a negative regulatory role in controlling de novo membrane phospholipid synthesis through its consumption of phosphatidate. We found that the pah1Δ mutant was defective in the utilization of non-fermentable carbon sources but not in oxidative phosphorylation; the mutant did not exhibit major changes in oxygen consumption rate, mitochondrial membrane potential, F1F0-ATP synthase activity, or gross mitochondrial morphology. The pah1Δ mutant contained an almost normal complement of major mitochondrial phospholipids with some alterations in molecular species. Although oxidative phosphorylation was not compromised in the pah1Δ mutant, the cellular levels of ATP in quiescent cells were reduced by 2-fold, inversely correlating with a 4-fold increase in membrane phospholipids. In addition, the quiescent pah1Δ mutant cells had 3-fold higher levels of mitochondrial superoxide and cellular lipid hydroperoxides, had reduced activities of superoxide dismutase 2 and catalase, and were hypersensitive to hydrogen peroxide. Consequently, the pah1Δ mutant had a shortened chronological life span. In addition, the loss of Tsa1 thioredoxin peroxidase caused a synthetic growth defect with the pah1Δ mutation. The shortened chronological life span of the pah1Δ mutant along with its growth defect on non-fermentable carbon sources and hypersensitivity to hydrogen peroxide was suppressed by the loss of Dgk1 diacylglycerol kinase, indicating that the underpinning of pah1Δ mutant defects was the excess synthesis of membrane phospholipids.
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Affiliation(s)
- Yeonhee Park
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Eugenia Mileykovskaya
- the Department of Biochemistry and Molecular Biology, University of Texas-Houston Medical School, Houston, Texas 77030, and
| | - Teresa A Garrett
- the Department of Chemistry, Vassar College, Poughkeepsie, New York 12604
| | - George M Carman
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901,
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74
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Mishra S, Schneiter R. Expression of perilipin 5 promotes lipid droplet formation in yeast. Commun Integr Biol 2015; 8:e1071728. [PMID: 27066172 PMCID: PMC4802777 DOI: 10.1080/19420889.2015.1071728] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/11/2014] [Accepted: 08/12/2014] [Indexed: 11/05/2022] Open
Abstract
Neutral lipids are packed into dedicated intracellular compartments termed lipid droplets (LDs). LDs are spherical structures delineated by an unusual lipid monolayer and they harbor a specific set of proteins, many of which function in lipid synthesis and lipid turnover. In mammals, LDs are covered by abundant scaffolding proteins, the perilipins (PLIN1–5). LDs in yeast are functionally similar to that of mammalian cells, but they lack the perilipins. We have previously shown that perilipins (PLIN1–3) are properly targeted to LDs when expressed in yeast and that they promote LD formation from the ER membrane enriched in neutral lipids. Here we address the question whether PLIN5 (OXPAT) has a similar function. Both human and murine PLIN5 were properly targeted to yeast LDs, but the protein localized to the cytosol and its steady-state level was reduced when expressed in yeast mutants lacking the capacity to synthesize storage lipids. When expressed in cells containing high levels of neutral lipids within the membrane of the endoplasmatic reticulum, PLIN5 promoted the formation of LDs. Interestingly, PLIN5 was properly targeted to LDs, irrespective of whether these LDs were filled with triacylglycerol or steryl esters, indicating that PLIN5 did not exhibit targeting specificity for a particular subtypes of LDs as was reported for mammalian cells.
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Affiliation(s)
- Shirish Mishra
- Department of Biology; Division of Biochemistry; University of Fribourg ; Fribourg, Switzerland
| | - Roger Schneiter
- Department of Biology; Division of Biochemistry; University of Fribourg ; Fribourg, Switzerland
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75
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Boneh A. Signal transduction in inherited metabolic disorders: a model for a possible pathogenetic mechanism. J Inherit Metab Dis 2015; 38:729-40. [PMID: 25735935 DOI: 10.1007/s10545-015-9820-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/20/2015] [Accepted: 02/02/2015] [Indexed: 01/08/2023]
Abstract
Signal transduction is the process by which external or internal signals exert their intracellular biological effects and by which intracellular communication is regulated. An important component of the signalling pathway is the second messenger, which is produced upon stimulation of the cell and mediates its effects downstream through phosphorylation and dephosphorylation of target proteins. Intracellular accumulation or deficiency of metabolites that serve as second messengers, due to inborn errors of their metabolism, may lead to perturbation of signalling pathways and disruption of the balance between them, serving as a missing link between the genotype, biochemical phenotype and clinical phenotype. The main second messengers that are putatively associated with the pathogenesis of IEM are 'bioactive lipids' (complex lipids and long-chain fatty acids), 'calcium', 'stress' (osmotic, reactive oxygen/nitorgen species, misfolded proteins and others) and 'metabolic' (AMP/ATP ratio, leucine, glutamine). They act through protein kinase C, calcium dependent kinases (CamK) and phosphatase (CN), 'stress-mediated' kinases (MAPK) and AMP/ATP-dependent kinase (AMPK). These signalling pathways lead to cell proliferation, inflammatory response, autophagy (and mitophagy) and apoptosis, suggesting that there are only few final common pathways involved in this pathogenetic mechanism. Questions remain regarding the complexity of the effects of the accumulating metabolites on different signalling pathways, and regarding the relative role and origin of 'proxy' second messengers such as reactive oxygen species. A better understanding of the signalling pathways in IEM may enhance the development of novel therapies in situations where normalising intracellular concentrations of the second messenger is impossible or impractical.
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Affiliation(s)
- Avihu Boneh
- Metabolic Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Vic, 3052, Melbourne, Australia,
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76
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Affiliation(s)
- Peixiang Zhang
- a Department of Human Genetics ; David Geffen School of Medicine at UCLA ; Los Angeles , CA USA
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77
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Shih DM, Yu JM, Vergnes L, Dali-Youcef N, Champion MD, Devarajan A, Zhang P, Castellani LW, Brindley DN, Jamey C, Auwerx J, Reddy ST, Ford DA, Reue K, Lusis AJ. PON3 knockout mice are susceptible to obesity, gallstone formation, and atherosclerosis. FASEB J 2015; 29:1185-97. [PMID: 25477283 PMCID: PMC4396607 DOI: 10.1096/fj.14-260570] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/07/2014] [Indexed: 11/11/2022]
Abstract
We report the engineering and characterization of paraoxonase-3 knockout mice (Pon3KO). The mice were generally healthy but exhibited quantitative alterations in bile acid metabolism and a 37% increased body weight compared to the wild-type mice on a high fat diet. PON3 was enriched in the mitochondria-associated membrane fraction of hepatocytes. PON3 deficiency resulted in impaired mitochondrial respiration, increased mitochondrial superoxide levels, and increased hepatic expression of inflammatory genes. PON3 deficiency did not influence atherosclerosis development on an apolipoprotein E null hyperlipidemic background, but it did lead to a significant 60% increase in atherosclerotic lesion size in Pon3KO mice on the C57BL/6J background when fed a cholate-cholesterol diet. On the diet, the Pon3KO had significantly increased plasma intermediate-density lipoprotein/LDL cholesterol and bile acid levels. They also exhibited significantly elevated levels of hepatotoxicity markers in circulation, a 58% increase in gallstone weight, a 40% increase in hepatic cholesterol level, and increased mortality. Furthermore, Pon3KO mice exhibited decreased hepatic bile acid synthesis and decreased bile acid levels in the small intestine compared with wild-type mice. Our study suggests a role for PON3 in the metabolism of lipid and bile acid as well as protection against atherosclerosis, gallstone disease, and obesity.
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Affiliation(s)
- Diana M Shih
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Janet M Yu
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Laurent Vergnes
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Nassim Dali-Youcef
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Matthew D Champion
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Asokan Devarajan
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Peixiang Zhang
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lawrence W Castellani
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - David N Brindley
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Carole Jamey
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Johan Auwerx
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Srinivasa T Reddy
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - David A Ford
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Karen Reue
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Aldons J Lusis
- *Division of Cardiology, Department of Medicine, Department of Microbiology, Immunology, and Molecular Genetics, Department of Human Genetics, Department of Molecular and Medical Pharmacology, and Department of Medicine and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California, USA; IGBMC, Illkirch and Hôpitaux Universitaires de Strasbourg, and **Laboratoire de Toxicologie, Universitaires de Strasbourg, Strasbourg, France; Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, St. Louis University School of Medicine, St. Louis, Missouri, USA; University of Alberta, Edmonton, Alberta, Canada; and Laboratory for Integrative and Systems Physiology, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Hsieh LS, Su WM, Han GS, Carman GM. Phosphorylation regulates the ubiquitin-independent degradation of yeast Pah1 phosphatidate phosphatase by the 20S proteasome. J Biol Chem 2015; 290:11467-78. [PMID: 25809482 DOI: 10.1074/jbc.m115.648659] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Indexed: 01/08/2023] Open
Abstract
Saccharomyces cerevisiae Pah1 phosphatidate phosphatase, which catalyzes the conversion of phosphatidate to diacylglycerol for triacylglycerol synthesis and simultaneously controls phosphatidate levels for phospholipid synthesis, is subject to the proteasome-mediated degradation in the stationary phase of growth. In this study, we examined the mechanism for its degradation using purified Pah1 and isolated proteasomes. Pah1 expressed in S. cerevisiae or Escherichia coli was not degraded by the 26S proteasome, but by its catalytic 20S core particle, indicating that its degradation is ubiquitin-independent. The degradation of Pah1 by the 20S proteasome was dependent on time and proteasome concentration at the pH optimum of 7.0. The 20S proteasomal degradation was conserved for human lipin 1 phosphatidate phosphatase. The degradation analysis using Pah1 truncations and its fusion with GFP indicated that proteolysis initiates at the N- and C-terminal unfolded regions. The folded region of Pah1, in particular the haloacid dehalogenase-like domain containing the DIDGT catalytic sequence, was resistant to the proteasomal degradation. The structural change of Pah1, as reflected by electrophoretic mobility shift, occurs through its phosphorylation by Pho85-Pho80, and the phosphorylation sites are located within its N- and C-terminal unfolded regions. Phosphorylation of Pah1 by Pho85-Pho80 inhibited its degradation, extending its half-life by ∼2-fold. The dephosphorylation of endogenously phosphorylated Pah1 by the Nem1-Spo7 protein phosphatase, which is highly specific for the sites phosphorylated by Pho85-Pho80, stimulated the 20S proteasomal degradation and reduced its half-life by 2.6-fold. These results indicate that the proteolysis of Pah1 by the 20S proteasome is controlled by its phosphorylation state.
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Affiliation(s)
- Lu-Sheng Hsieh
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Wen-Min Su
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
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79
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Morphogenesis checkpoint kinase Swe1 is the executor of lipolysis-dependent cell-cycle progression. Proc Natl Acad Sci U S A 2015; 112:E1077-85. [PMID: 25713391 DOI: 10.1073/pnas.1423175112] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cell growth and division requires the precise duplication of cellular DNA content but also of membranes and organelles. Knowledge about the cell-cycle-dependent regulation of membrane and storage lipid homeostasis is only rudimentary. Previous work from our laboratory has shown that the breakdown of triacylglycerols (TGs) is regulated in a cell-cycle-dependent manner, by activation of the Tgl4 lipase by the major cyclin-dependent kinase Cdc28. The lipases Tgl3 and Tgl4 are required for efficient cell-cycle progression during the G1/S (Gap1/replication phase) transition, at the onset of bud formation, and their absence leads to a cell-cycle delay. We now show that defective lipolysis activates the Swe1 morphogenesis checkpoint kinase that halts cell-cycle progression by phosphorylation of Cdc28 at tyrosine residue 19. Saturated long-chain fatty acids and phytosphingosine supplementation rescue the cell-cycle delay in the Tgl3/Tgl4 lipase-deficient strain, suggesting that Swe1 activity responds to imbalanced sphingolipid metabolism, in the absence of TG degradation. We propose a model by which TG-derived sphingolipids are required to activate the protein phosphatase 2A (PP2A(Cdc55)) to attenuate Swe1 phosphorylation and its inhibitory effect on Cdc28 at the G1/S transition of the cell cycle.
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80
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Frohman MA. The phospholipase D superfamily as therapeutic targets. Trends Pharmacol Sci 2015; 36:137-44. [PMID: 25661257 DOI: 10.1016/j.tips.2015.01.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/11/2015] [Accepted: 01/13/2015] [Indexed: 01/03/2023]
Abstract
The phospholipase D (PLD) lipid-signaling enzyme superfamily has long been studied for its roles in cell communication and a wide range of cell biological processes. With the advent of loss-of-function genetic mouse models that have revealed that PLD1 and PLD2 ablation is overtly tolerable, small-molecule PLD1/2 inhibitors that do not cause unacceptable clinical toxicity, a PLD2 polymorphism that has been linked to altered physiology, and growing delineation of processes that are subtly altered in mice lacking PLD1/2 activity, the stage is being set for assessment of PLD1/2 inhibition for therapeutic purposes. Based on findings to date, PLD1/2 inhibition may be of more utility in acute rather than chronic settings, although this generalization will depend on the specific risks and benefits in each disease setting.
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Affiliation(s)
- Michael A Frohman
- Department of Pharmacological Sciences and the Center for Developmental Genetics, 438 Centers for Molecular Medicine, Stony Brook University, Stony Brook, NY 11794-5140, USA.
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81
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Bi L, Jiang Z, Zhou J. The role of lipin-1 in the pathogenesis of alcoholic fatty liver. Alcohol Alcohol 2015; 50:146-51. [PMID: 25595739 DOI: 10.1093/alcalc/agu102] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIMS The aim of this review was to focus on the knowledge of the role of lipin-1 in the pathogenesis of alcoholic fatty liver. METHODS Systematic review of animal clinical and cell level studies related to the function of lipin-1 on alcoholic fatty liver, alcoholic hepatitis and alcoholic liver cirrhosis disease. RESULT Ethanol could increase the expression of lipin-1 through the AMPK-SREBP-1 signaling and dramatically increase the ratio of Lpin1β to Lpin1α by SIRT1-SFRS10-Lpin1β/α axis in the liver. Moreover, research has shown that over-expression of lipin-1 could also remarkably suppress very low density lipoprotein-triacylglyceride secretion. Last, lipin-1 has potent anti-inflammatory property. CONCLUSION In conclusion, lipin-1 has dual functions in lipid metabolism. In the cytoplasm, lipin-1β functions as a Mg(2+)-dependent phosphatidic acid phosphohydrolase (PAP) enzyme in triglyceride synthesis pathways. In the nucleus, lipin-1α acts as a transcriptional co-regulator to regulate the capacity of the liver for fatty acid oxidation and activity of the lipogenic enzyme. In hepatocytes of alcoholic fatty liver disease (AFLD), ethanol increases the expression of lipin-1 through the AMPK-SREBP-1 signaling and the Lpin1β/α ratio by SIRT1-SFRS10- Lpin1β/α axis. Of course, in addition to that, ethanol could also produce the PAP activity and interrupt the nucleus function of lipin-1. Furthermore, over-expression of lipin-1 could remarkably suppress very low-density lipoprotein-triacylglyceride (VLDL-TAG) secretion. In the end, endogenous lipin-1 has potent anti-inflammatory property. Increased synthesis of TAG, decreased fatty acid oxidation, impaired VLDL-TAG secretion and activated inflammatory factors act together to exacerbate the development of AFLD.
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Affiliation(s)
- Lijuan Bi
- Department of Infectious Disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Zhian Jiang
- Department of Infectious Disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Junying Zhou
- Department of Infectious Disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
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Garcia-Cazorla À, Mochel F, Lamari F, Saudubray JM. The clinical spectrum of inherited diseases involved in the synthesis and remodeling of complex lipids. A tentative overview. J Inherit Metab Dis 2015; 38:19-40. [PMID: 25413954 DOI: 10.1007/s10545-014-9776-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/16/2014] [Accepted: 09/23/2014] [Indexed: 12/19/2022]
Abstract
Over one hundred diseases related to inherited defects of complex lipids synthesis and remodeling are now reported. Most of them were described within the last 5 years. New descriptions and phenotypes are expanding rapidly. While the associated clinical phenotype is currently difficult to outline, with only a few patients identified, it appears that all organs and systems may be affected. The main clinical presentations can be divided into (1) Diseases affecting the central and peripheral nervous system. Complex lipid synthesis disorders produce prominent motor manifestations due to upper and/or lower motoneuron degeneration. Motor signs are often complex, associated with other neurological and extra-neurological signs. Three neurological phenotypes, spastic paraparesis, neurodegeneration with brain iron accumulation and peripheral neuropathies, deserve special attention. Many apparently well clinically defined syndromes are not distinct entities, but rather clusters on a continuous spectrum, like for the PNPLA6-associated diseases, extending from Boucher-Neuhauser syndrome via Gordon Holmes syndrome to spastic ataxia and pure hereditary spastic paraplegia; (2) Muscular/cardiac presentations; (3) Skin symptoms mostly represented by syndromic (neurocutaneous) and non syndromic ichthyosis; (4) Retinal dystrophies with syndromic and non syndromic retinitis pigmentosa, Leber congenital amaurosis, cone rod dystrophy, Stargardt disease; (5) Congenital bone dysplasia and segmental overgrowth disorders with congenital lipomatosis; (6) Liver presentations characterized mainly by transient neonatal cholestatic jaundice and non alcoholic liver steatosis with hypertriglyceridemia; and (7) Renal and immune presentations. Lipidomics and molecular functional studies could help to elucidate the mechanism(s) of dominant versus recessive inheritance observed for the same gene in a growing number of these disorders.
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Affiliation(s)
- Àngels Garcia-Cazorla
- Department of Neurology, Neurometabolic Unit, Hospital Sant Joan de Déu and CIBERER, ISCIII, Barcelona, Spain,
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83
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Lamari F, Mochel F, Saudubray JM. An overview of inborn errors of complex lipid biosynthesis and remodelling. J Inherit Metab Dis 2015; 38:3-18. [PMID: 25238787 DOI: 10.1007/s10545-014-9764-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/08/2014] [Accepted: 08/14/2014] [Indexed: 01/10/2023]
Abstract
In a review published in 2012, we delineated 14 inborn errors of metabolism (IEM) related to defects in biosynthesis of complex lipids, particularly phospholipids and sphingolipids (Lamari et al 2013). Given the numerous roles played by these molecules in membrane integrity, cell structure and function, this group of diseases is rapidly expanding as predicted. Almost 40 new diseases related to genetic defects in enzymes involved in the biosynthesis and remodelling of phospholipids, sphingolipids and complex fatty acids are now reported. While the clinical phenotype associated with these defects is currently difficult to outline, with only a few patients identified to date, it appears that all organs and systems may be affected - central and peripheral nervous system, eye, muscle, skin, bone, liver, immune system, etc. This chapter presents an introductive overview of this new group of IEM. More broadly, this special issue provides an update on other IEM involving complex lipids, namely dolichol and isoprenoids, glycolipids and congenital disorders of glycosylation, very long chain fatty acids and plasmalogens. Likewise, more than 100 IEM may actually lead to primary or secondary defects of complex lipids synthesis and remodelling. Because of the implication of several cellular compartments, this new group of disorders affecting the synthesis and remodelling of complex molecules challenges our current classification of IEM still largely based on cellular organelles--i.e. mitochondrial, lysosomal, peroxisomal disorders. While most of these new disorders have been identified by next generation sequencing, we wish to emphasize the promising role of lipidomics in deciphering their pathophysiology and identifying therapeutic targets.
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Affiliation(s)
- Foudil Lamari
- Bioclinic and Genetic Unit of Neurometabolic Diseases, Pitié-Salpêtrière Hospital, (APHP), Paris, 75013, France
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84
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Su WM, Han GS, Carman GM. Yeast Nem1-Spo7 protein phosphatase activity on Pah1 phosphatidate phosphatase is specific for the Pho85-Pho80 protein kinase phosphorylation sites. J Biol Chem 2014; 289:34699-708. [PMID: 25359770 DOI: 10.1074/jbc.m114.614883] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pah1 is the phosphatidate phosphatase in the yeast Saccharomyces cerevisiae that produces diacylglycerol for triacylglycerol synthesis and concurrently controls the levels of phosphatidate used for phospholipid synthesis. Phosphorylation and dephosphorylation of Pah1 regulate its subcellular location and phosphatidate phosphatase activity. Compared with its phosphorylation by multiple protein kinases, Pah1 is dephosphorylated by a protein phosphatase complex consisting of Nem1 (catalytic subunit) and Spo7 (regulatory subunit). In this work, we characterized the Nem1-Spo7 phosphatase complex for its enzymological, kinetic, and regulatory properties with phosphorylated Pah1. The dephosphorylation of Pah1 by Nem1-Spo7 phosphatase resulted in the stimulation (6-fold) of phosphatidate phosphatase activity. For Pah1 phosphorylated by the Pho85-Pho80 kinase complex, maximum Nem1-Spo7 phosphatase activity required Mg(2+) ions (8 mm) and Triton X-100 (0.25 mm) at pH 5.0. The energy of activation for the reaction was 8.4 kcal/mol, and the enzyme was thermally labile at temperatures above 40 °C. The enzyme activity was inhibited by sodium vanadate, sodium fluoride, N-ethylmaleimide, and phenylglyoxal but was not significantly affected by lipids or nucleotides. Nem1-Spo7 phosphatase activity was dependent on the concentrations of Pah1 phosphorylated by Pho85-Pho80, Cdc28-cyclin B, PKA, and PKC with kcat and Km values of 0.29 s(-1) and 81 nm, 0.11 s(-1) and 127 nm, 0.10 s(-1) and 46 nm, and 0.02 s(-1) and 38 nm, respectively. Its specificity constant (kcat/Km) for Pah1 phosphorylated by Pho85-Pho80 was 1.6-, 4-, and 6-fold higher, respectively, than that phosphorylated by PKA, Cdc28-cyclin B, and PKC.
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Affiliation(s)
- Wen-Min Su
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
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85
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Roberts DJ, Miyamoto S. Hexokinase II integrates energy metabolism and cellular protection: Akting on mitochondria and TORCing to autophagy. Cell Death Differ 2014; 22:248-57. [PMID: 25323588 DOI: 10.1038/cdd.2014.173] [Citation(s) in RCA: 281] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/11/2014] [Accepted: 09/15/2014] [Indexed: 01/08/2023] Open
Abstract
Accumulating evidence reveals that metabolic and cell survival pathways are closely related, sharing common signaling molecules. Hexokinase catalyzes the phosphorylation of glucose, the rate-limiting first step of glycolysis. Hexokinase II (HK-II) is a predominant isoform in insulin-sensitive tissues such as heart, skeletal muscle, and adipose tissues. It is also upregulated in many types of tumors associated with enhanced aerobic glycolysis in tumor cells, the Warburg effect. In addition to the fundamental role in glycolysis, HK-II is increasingly recognized as a component of a survival signaling nexus. This review summarizes recent advances in understanding the protective role of HK-II, controlling cellular growth, preventing mitochondrial death pathway and enhancing autophagy, with a particular focus on the interaction between HK-II and Akt/mTOR pathway to integrate metabolic status with the control of cell survival.
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Affiliation(s)
- D J Roberts
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | - S Miyamoto
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA
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86
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Williams JA, Manley S, Ding WX. New advances in molecular mechanisms and emerging therapeutic targets in alcoholic liver diseases. World J Gastroenterol 2014; 20:12908-12933. [PMID: 25278688 PMCID: PMC4177473 DOI: 10.3748/wjg.v20.i36.12908] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/07/2014] [Accepted: 04/16/2014] [Indexed: 02/06/2023] Open
Abstract
Alcoholic liver disease is a major health problem in the United States and worldwide. Chronic alcohol consumption can cause steatosis, inflammation, fibrosis, cirrhosis and even liver cancer. Significant progress has been made to understand key events and molecular players for the onset and progression of alcoholic liver disease from both experimental and clinical alcohol studies. No successful treatments are currently available for treating alcoholic liver disease; therefore, development of novel pathophysiological-targeted therapies is urgently needed. This review summarizes the recent progress on animal models used to study alcoholic liver disease and the detrimental factors that contribute to alcoholic liver disease pathogenesis including miRNAs, S-adenosylmethionine, Zinc deficiency, cytosolic lipin-1β, IRF3-mediated apoptosis, RIP3-mediated necrosis and hepcidin. In addition, we summarize emerging adaptive protective effects induced by alcohol to attenuate alcohol-induced liver pathogenesis including FoxO3, IL-22, autophagy and nuclear lipin-1α.
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87
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Yen CLE, Nelson DW, Yen MI. Intestinal triacylglycerol synthesis in fat absorption and systemic energy metabolism. J Lipid Res 2014; 56:489-501. [PMID: 25231105 DOI: 10.1194/jlr.r052902] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The intestine plays a prominent role in the biosynthesis of triacylglycerol (triglyceride; TAG). Digested dietary TAG is repackaged in the intestine to form the hydrophobic core of chylomicrons, which deliver metabolic fuels, essential fatty acids, and other lipid-soluble nutrients to the peripheral tissues. By controlling the flux of dietary fat into the circulation, intestinal TAG synthesis can greatly impact systemic metabolism. Genes encoding many of the enzymes involved in TAG synthesis have been identified. Among TAG synthesis enzymes, acyl-CoA:monoacylglycerol acyltransferase 2 and acyl-CoA:diacylglycerol acyltransferase (DGAT)1 are highly expressed in the intestine. Their physiological functions have been examined in the context of whole organisms using genetically engineered mice and, in the case of DGAT1, specific inhibitors. An emerging theme from recent findings is that limiting the rate of TAG synthesis in the intestine can modulate gut hormone secretion, lipid metabolism, and systemic energy balance. The underlying mechanisms and their implications for humans are yet to be explored. Pharmacological inhibition of TAG hydrolysis in the intestinal lumen has been employed to combat obesity and associated disorders with modest efficacy and unwanted side effects. The therapeutic potential of inhibiting specific enzymes involved in intestinal TAG synthesis warrants further investigation.
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Affiliation(s)
- Chi-Liang Eric Yen
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706.
| | - David W Nelson
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706
| | - Mei-I Yen
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706
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88
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Characterization of a soluble phosphatidic acid phosphatase in bitter melon (Momordica charantia). PLoS One 2014; 9:e106403. [PMID: 25203006 PMCID: PMC4159287 DOI: 10.1371/journal.pone.0106403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 08/05/2014] [Indexed: 11/19/2022] Open
Abstract
Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and Pi. PAPs are typically categorized into two subfamilies: Mg2+-dependent soluble PAP and Mg2+-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg2+-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53–60°C and unaffected by up to 0.3 mM MgCl2. The Km and Vmax values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na3VO4, Triton X-100, FeSO4 and CuSO4, but stimulated by MnSO4, ZnSO4 and Co(NO3)2. In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg2+-independent enzyme in plants.
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89
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da Silva RP, Kelly KB, Leonard KA, Jacobs RL. Creatine reduces hepatic TG accumulation in hepatocytes by stimulating fatty acid oxidation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1639-46. [PMID: 25205520 DOI: 10.1016/j.bbalip.2014.09.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/15/2014] [Accepted: 09/02/2014] [Indexed: 12/22/2022]
Abstract
Non-alcoholic fatty liver disease encompasses a wide spectrum of liver damage including steatosis, non-alcoholic steatohepatitis, fibrosis and cirrhosis. We have previously reported that creatine supplementation prevents hepatic steatosis and lipid peroxidation in rats fed a high-fat diet. In this study, we employed oleate-treated McArdle RH-7777 rat hepatoma cells to investigate the role of creatine in regulating hepatic lipid metabolism. Creatine, but not structural analogs, reduced cellular TG accumulation in a dose-dependent manner. Incubating cells with the pan-lipase inhibitor diethyl p-nitrophenylphosphate (E600) did not diminish the effect of creatine, demonstrating that the TG reduction brought about by creatine does not depend on lipolysis. Radiolabeled tracer experiments indicate that creatine increases fatty acid oxidation and TG secretion. In line with increased fatty acid oxidation, mRNA analysis revealed that creatine-treated cells had increased expression of PPARα and several of its transcriptional targets. Taken together, this study provides direct evidence that creatine reduces lipid accumulation in hepatocytes by the stimulation of fatty acid oxidation and TG secretion.
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Affiliation(s)
- Robin P da Silva
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Karen B Kelly
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Kelly-Ann Leonard
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
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90
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Gorné LD, Acosta-Rodríguez VA, Pasquaré SJ, Salvador GA, Giusto NM, Guido ME. The mouse liver displays daily rhythms in the metabolism of phospholipids and in the activity of lipid synthesizing enzymes. Chronobiol Int 2014; 32:11-26. [PMID: 25140391 DOI: 10.3109/07420528.2014.949734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The circadian system involves central and peripheral oscillators regulating temporally biochemical processes including lipid metabolism; their disruption leads to severe metabolic diseases (obesity, diabetes, etc). Here, we investigated the temporal regulation of glycerophospholipid (GPL) synthesis in mouse liver, a well-known peripheral oscillator. Mice were synchronized to a 12:12 h light-dark (LD) cycle and then released to constant darkness with food ad libitum. Livers collected at different times exhibited a daily rhythmicity in some individual GPL content with highest levels during the subjective day. The activity of GPL-synthesizing/remodeling enzymes: phosphatidate phosphohydrolase 1 (PAP-1/lipin) and lysophospholipid acyltransferases (LPLATs) also displayed significant variations, with higher levels during the subjective day and at dusk. We evaluated the temporal regulation of expression and activity of phosphatidylcholine (PC) synthesizing enzymes. PC is mainly synthesized through the Kennedy pathway with Choline Kinase (ChoK) as a key regulatory enzyme or through the phosphatidylethanolamine (PE) N-methyltransferase (PEMT) pathway. The PC/PE content ratio exhibited a daily variation with lowest levels at night, while ChoKα and PEMT mRNA expression displayed maximal levels at nocturnal phases. Our results demonstrate that mouse liver GPL metabolism oscillates rhythmically with a precise temporal control in the expression and/or activity of specific enzymes.
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Affiliation(s)
- Lucas D Gorné
- Departamento de Química Biológica, Facultad de Ciencias Químicas, CIQUIBIC-CONICET, Universidad Nacional de Córdoba , Córdoba , Argentina and
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91
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Dubots E, Cottier S, Péli-Gulli MP, Jaquenoud M, Bontron S, Schneiter R, De Virgilio C. TORC1 regulates Pah1 phosphatidate phosphatase activity via the Nem1/Spo7 protein phosphatase complex. PLoS One 2014; 9:e104194. [PMID: 25117580 PMCID: PMC4130541 DOI: 10.1371/journal.pone.0104194] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 07/05/2014] [Indexed: 01/01/2023] Open
Abstract
The evolutionarily conserved target of rapamycin complex 1 (TORC1) controls growth-related processes such as protein, nucleotide, and lipid metabolism in response to growth hormones, energy/ATP levels, and amino acids. Its deregulation is associated with cancer, type 2 diabetes, and obesity. Among other substrates, mammalian TORC1 directly phosphorylates and inhibits the phosphatidate phosphatase lipin-1, a central enzyme in lipid metabolism that provides diacylglycerol for the synthesis of membrane phospholipids and/or triacylglycerol as neutral lipid reserve. Here, we show that yeast TORC1 inhibits the function of the respective lipin, Pah1, to prevent the accumulation of triacylglycerol. Surprisingly, TORC1 regulates Pah1 in part indirectly by controlling the phosphorylation status of Nem1 within the Pah1-activating, heterodimeric Nem1-Spo7 protein phosphatase module. Our results delineate a hitherto unknown TORC1 effector branch that controls lipin function in yeast, which, given the recent discovery of Nem1-Spo7 orthologous proteins in humans, may be conserved.
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Affiliation(s)
- Emmanuelle Dubots
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Stéphanie Cottier
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | | | - Malika Jaquenoud
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Séverine Bontron
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Roger Schneiter
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
- * E-mail:
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92
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Zhang P, Verity MA, Reue K. Lipin-1 regulates autophagy clearance and intersects with statin drug effects in skeletal muscle. Cell Metab 2014; 20:267-79. [PMID: 24930972 PMCID: PMC4170588 DOI: 10.1016/j.cmet.2014.05.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/03/2014] [Accepted: 04/21/2014] [Indexed: 02/04/2023]
Abstract
LPIN1 encodes lipin-1, a phosphatidic acid phosphatase (PAP) enzyme that catalyzes the dephosphorylation of phosphatidic acid to form diacylglycerol. Homozygous LPIN1 gene mutations cause severe rhabdomyolysis, and heterozygous LPIN1 missense mutations may promote statin-induced myopathy. We demonstrate that lipin-1-related myopathy in the mouse is associated with a blockade in autophagic flux and accumulation of aberrant mitochondria. Lipin-1 PAP activity is required for maturation of autolysosomes, through its activation of the protein kinase D (PKD)-Vps34 phosphatidylinositol 3-kinase signaling cascade. Statin treatment also reduces PKD activation and autophagic flux, which are compounded by diminished mammalian target of rapamycin (mTOR) abundance in lipin-1-haploinsufficent and -deficient muscle. Lipin-1 restoration in skeletal muscle prevents myonecrosis and statin toxicity in vivo, and activated PKD rescues autophagic flux in lipin-1-deficient cells. Our findings identify lipin-1 PAP activity as a component of the macroautophagy pathway and define the basis for lipin-1-related myopathies.
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Affiliation(s)
- Peixiang Zhang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - M Anthony Verity
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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93
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Parvaneh N, Quartier P, Rostami P, Casanova JL, de Lonlay P. Inborn errors of metabolism underlying primary immunodeficiencies. J Clin Immunol 2014; 34:753-71. [PMID: 25081841 DOI: 10.1007/s10875-014-0076-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/02/2014] [Indexed: 01/19/2023]
Abstract
A number of inborn errors of metabolism (IEM) have been shown to result in predominantly immunologic phenotypes, manifesting in part as inborn errors of immunity. These phenotypes are mostly caused by defects that affect the (i) quality or quantity of essential structural building blocks (e.g., nucleic acids, and amino acids), (ii) cellular energy economy (e.g., glucose metabolism), (iii) post-translational protein modification (e.g., glycosylation) or (iv) mitochondrial function. Presenting as multisystemic defects, they also affect innate or adaptive immunity, or both, and display various types of immune dysregulation. Specific and potentially curative therapies are available for some of these diseases, whereas targeted treatments capable of inducing clinical remission are available for others. We will herein review the pathogenesis, diagnosis, and treatment of primary immunodeficiencies (PIDs) due to underlying metabolic disorders.
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Affiliation(s)
- Nima Parvaneh
- Research Center for Immunodeficiencies, Tehran University of Medical Sciences, Tehran, Iran,
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94
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Eaton JM, Takkellapati S, Lawrence RT, McQueeney KE, Boroda S, Mullins GR, Sherwood SG, Finck BN, Villén J, Harris TE. Lipin 2 binds phosphatidic acid by the electrostatic hydrogen bond switch mechanism independent of phosphorylation. J Biol Chem 2014; 289:18055-66. [PMID: 24811178 DOI: 10.1074/jbc.m114.547604] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipin 2 is a phosphatidic acid phosphatase (PAP) responsible for the penultimate step of triglyceride synthesis and dephosphorylation of phosphatidic acid (PA) to generate diacylglycerol. The lipin family of PA phosphatases is composed of lipins 1-3, which are members of the conserved haloacid dehalogenase superfamily. Although genetic alteration of LPIN2 in humans is known to cause Majeed syndrome, little is known about the biochemical regulation of its PAP activity. Here, in an attempt to gain a better general understanding of the biochemical nature of lipin 2, we have performed kinetic and phosphorylation analyses. We provide evidence that lipin 2, like lipin 1, binds PA via the electrostatic hydrogen bond switch mechanism but has a lower rate of catalysis. Like lipin 1, lipin 2 is highly phosphorylated, and we identified 15 phosphosites. However, unlike lipin 1, the phosphorylation of lipin 2 is not induced by insulin signaling nor is it sensitive to inhibition of the mammalian target of rapamycin. Importantly, phosphorylation of lipin 2 does not negatively regulate either membrane binding or PAP activity. This suggests that lipin 2 functions as a constitutively active PA phosphatase in stark contrast to the high degree of phosphorylation-mediated regulation of lipin 1. This knowledge of lipin 2 regulation is important for a deeper understanding of how the lipin family functions with respect to lipid synthesis and, more generally, as an example of how the membrane environment around PA can influence its effector proteins.
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Affiliation(s)
- James M Eaton
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Sankeerth Takkellapati
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Robert T Lawrence
- the Department of Genome Sciences, University of Washington, Seattle, Washington 98105
| | - Kelley E McQueeney
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Salome Boroda
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Garrett R Mullins
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Samantha G Sherwood
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Brian N Finck
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, and
| | - Judit Villén
- the Department of Genome Sciences, University of Washington, Seattle, Washington 98105
| | - Thurl E Harris
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908,
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95
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Kok BPC, Skene-Arnold TD, Ling J, Benesch MGK, Dewald J, Harris TE, Holmes CFB, Brindley DN. Conserved residues in the N terminus of lipin-1 are required for binding to protein phosphatase-1c, nuclear translocation, and phosphatidate phosphatase activity. J Biol Chem 2014; 289:10876-10886. [PMID: 24558042 DOI: 10.1074/jbc.m114.552612] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipin-1 is a phosphatidate phosphatase in glycerolipid biosynthesis and signal transduction. It also serves as a transcriptional co-regulator to control lipid metabolism and adipogenesis. These functions are controlled partly by its subcellular distribution. Hyperphosphorylated lipin-1 remains sequestered in the cytosol, whereas hypophosphorylated lipin-1 translocates to the endoplasmic reticulum and nucleus. The serine/threonine protein phosphatase-1 catalytic subunit (PP-1c) is a major protein dephosphorylation enzyme. Its activity is controlled by interactions with different regulatory proteins, many of which contain conserved RVXF binding motifs. We found that lipin-1 binds to PP-1cγ through a similar HVRF binding motif. This interaction depends on Mg(2+) or Mn(2+) and is competitively inhibited by (R/H)VXF-containing peptides. Mutating the HVRF motif in the highly conserved N terminus of lipin-1 greatly decreases PP-1cγ interaction. Moreover, mutations of other residues in the N terminus of lipin-1 also modulate PP-1cγ binding. PP-1cγ binds poorly to a phosphomimetic mutant of lipin-1 and binds well to the non-phosphorylatable lipin-1 mutant. This indicates that lipin-1 is dephosphorylated before PP-1cγ binds to its HVRF motif. Importantly, mutating the HVRF motif also abrogates the nuclear translocation and phosphatidate phosphatase activity of lipin-1. In conclusion, we provide novel evidence of the importance of the lipin-1 N-terminal domain for its catalytic activity, nuclear localization, and binding to PP-1cγ.
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Affiliation(s)
- Bernard P C Kok
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Tamara D Skene-Arnold
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Ji Ling
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Matthew G K Benesch
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Jay Dewald
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesvillle, Virginia 22908
| | - Charles F B Holmes
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - David N Brindley
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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96
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Levy D, Ruiz JLM, Celestino AT, Silva SF, Ferreira AK, Isaac C, Bydlowski SP. Short-term effects of 7-ketocholesterol on human adipose tissue mesenchymal stem cells in vitro. Biochem Biophys Res Commun 2014; 446:720-5. [PMID: 24491549 DOI: 10.1016/j.bbrc.2014.01.132] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 01/25/2014] [Indexed: 01/27/2023]
Abstract
Oxysterols comprise a very heterogeneous group derived from cholesterol through enzymatic and non-enzymatic oxidation. Among them, 7-ketocholesterol (7-KC) is one of the most important. It has potent effects in cell death processes, including cytoxicity and apoptosis induction. Mesenchymal stem cells (MSCs) are multipotent cells characterized by self-renewal and cellular differentiation capabilities. Very little is known about the effects of oxysterols in MSCs. Here, we describe the short-term cytotoxic effect of 7-ketocholesterol on MSCs derived from human adipose tissue. MSCs were isolated from adipose tissue obtained from two young, healthy women. After 24 h incubation with 7-KC, mitochondrial hyperpolarization was observed, followed by a slight increase in the level of apoptosis and changes in actin organization. Finally, the IC50 of 7-KC was higher in these cells than has been observed or described in other normal or cancer cell lines.
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Affiliation(s)
- Débora Levy
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av. Dr. Enéas de Carvalho Aguiar,155, 1st Floor, Room 43, 05403-000 São Paulo, SP, Brazil
| | - Jorge Luis Maria Ruiz
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av. Dr. Enéas de Carvalho Aguiar,155, 1st Floor, Room 43, 05403-000 São Paulo, SP, Brazil
| | - Andrea Turbuck Celestino
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av. Dr. Enéas de Carvalho Aguiar,155, 1st Floor, Room 43, 05403-000 São Paulo, SP, Brazil
| | - Suelen Feitoza Silva
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av. Dr. Enéas de Carvalho Aguiar,155, 1st Floor, Room 43, 05403-000 São Paulo, SP, Brazil
| | - Adilson Kleber Ferreira
- Departament of Immunology, Laboratory of Tumor Immunology, Institute of Biomedical Science, University of Sao Paulo, Av. Prof. Lineu Prestes, 1730-Room 254, 05508-900 São Paulo, SP, Brazil
| | - Cesar Isaac
- Cell Culture and Wound Healing Research Laboratory, Division of Plastic Surgery, University of São Paulo, Av. Dr. Arnaldo, 455, 1st Floor, 05403-000 São Paulo, SP, Brazil
| | - Sérgio Paulo Bydlowski
- Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo School of Medicine, Av. Dr. Enéas de Carvalho Aguiar,155, 1st Floor, Room 43, 05403-000 São Paulo, SP, Brazil.
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97
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Csaki LS, Dwyer JR, Li X, Nguyen MHK, Dewald J, Brindley DN, Lusis AJ, Yoshinaga Y, de Jong P, Fong L, Young SG, Reue K. Lipin-1 and lipin-3 together determine adiposity in vivo. Mol Metab 2013; 3:145-54. [PMID: 24634820 DOI: 10.1016/j.molmet.2013.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/17/2013] [Accepted: 11/21/2013] [Indexed: 12/17/2022] Open
Abstract
The lipin protein family of phosphatidate phosphatases has an established role in triacylglycerol synthesis and storage. Physiological roles for lipin-1 and lipin-2 have been identified, but the role of lipin-3 has remained mysterious. Using lipin single- and double-knockout models we identified a cooperative relationship between lipin-3 and lipin-1 that influences adipogenesis in vitro and adiposity in vivo. Furthermore, natural genetic variations in Lpin1 and Lpin3 expression levels across 100 mouse strains correlate with adiposity. Analysis of PAP activity in additional metabolic tissues from lipin single- and double-knockout mice also revealed roles for lipin-1 and lipin-3 in spleen, kidney, and liver, for lipin-1 alone in heart and skeletal muscle, and for lipin-1 and lipin-2 in lung and brain. Our findings establish that lipin-1 and lipin-3 cooperate in vivo to determine adipose tissue PAP activity and adiposity, and may have implications in understanding the protection of lipin-1-deficient humans from overt lipodystrophy.
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Affiliation(s)
- Lauren S Csaki
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Jennifer R Dwyer
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Xia Li
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Michael H K Nguyen
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Jay Dewald
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Alberta, Canada
| | - David N Brindley
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Alberta, Canada
| | - Aldons J Lusis
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA ; Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA ; Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Yuko Yoshinaga
- Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA ; Current address: Department of Energy (DOE) Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Pieter de Jong
- Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Loren Fong
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephen G Young
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA ; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA ; Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA ; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA ; Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Horvath SE, Daum G. Lipids of mitochondria. Prog Lipid Res 2013; 52:590-614. [PMID: 24007978 DOI: 10.1016/j.plipres.2013.07.002] [Citation(s) in RCA: 613] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 07/31/2013] [Indexed: 01/06/2023]
Abstract
A unique organelle for studying membrane biochemistry is the mitochondrion whose functionality depends on a coordinated supply of proteins and lipids. Mitochondria are capable of synthesizing several lipids autonomously such as phosphatidylglycerol, cardiolipin and in part phosphatidylethanolamine, phosphatidic acid and CDP-diacylglycerol. Other mitochondrial membrane lipids such as phosphatidylcholine, phosphatidylserine, phosphatidylinositol, sterols and sphingolipids have to be imported. The mitochondrial lipid composition, the biosynthesis and the import of mitochondrial lipids as well as the regulation of these processes will be main issues of this review article. Furthermore, interactions of lipids and mitochondrial proteins which are highly important for various mitochondrial processes will be discussed. Malfunction or loss of enzymes involved in mitochondrial phospholipid biosynthesis lead to dysfunction of cell respiration, affect the assembly and stability of the mitochondrial protein import machinery and cause abnormal mitochondrial morphology or even lethality. Molecular aspects of these processes as well as diseases related to defects in the formation of mitochondrial membranes will be described.
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Affiliation(s)
- Susanne E Horvath
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
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