51
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Shin HW, Takatsu H. Substrates of P4‐ATPases: beyond aminophospholipids (phosphatidylserine and phosphatidylethanolamine). FASEB J 2018; 33:3087-3096. [DOI: 10.1096/fj.201801873r] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hye-Won Shin
- Graduate School of Pharmaceutical SciencesKyoto University Kyoto Japan
| | - Hiroyuki Takatsu
- Graduate School of Pharmaceutical SciencesKyoto University Kyoto Japan
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52
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Kilian N, Choi JY, Voelker DR, Ben Mamoun C. Role of phospholipid synthesis in the development and differentiation of malaria parasites in the blood. J Biol Chem 2018; 293:17308-17316. [PMID: 30287688 DOI: 10.1074/jbc.r118.003213] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The life cycle of malaria parasites in both their mammalian host and mosquito vector consists of multiple developmental stages that ensure proper replication and progeny survival. The transition between these stages is fueled by nutrients scavenged from the host and fed into specialized metabolic pathways of the parasite. One such pathway is used by Plasmodium falciparum, which causes the most severe form of human malaria, to synthesize its major phospholipids, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Much is known about the enzymes involved in the synthesis of these phospholipids, and recent advances in genetic engineering, single-cell RNA-Seq analyses, and drug screening have provided new perspectives on the importance of some of these enzymes in parasite development and sexual differentiation and have identified targets for the development of new antimalarial drugs. This Minireview focuses on two phospholipid biosynthesis enzymes of P. falciparum that catalyze phosphoethanolamine transmethylation (PfPMT) and phosphatidylserine decarboxylation (PfPSD) during the blood stages of the parasite. We also discuss our current understanding of the biochemical, structural, and biological functions of these enzymes and highlight efforts to use them as antimalarial drug targets.
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Affiliation(s)
- Nicole Kilian
- From the Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut 06520 and
| | - Jae-Yeon Choi
- the Basic Science Section, Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Dennis R Voelker
- the Basic Science Section, Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Choukri Ben Mamoun
- From the Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut 06520 and
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53
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Small-Molecule Modulation of Lipid-Dependent Cellular Processes against Cancer: Fats on the Gunpoint. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6437371. [PMID: 30186863 PMCID: PMC6114229 DOI: 10.1155/2018/6437371] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 07/22/2018] [Indexed: 12/27/2022]
Abstract
Lipid cell membrane composed of various distinct lipids and proteins act as a platform to assemble various signaling complexes regulating innumerous cellular processes which are strongly downregulated or altered in cancer cells emphasizing the still-underestimated critical function of lipid biomolecules in cancer initiation and progression. In this review, we outline the current understanding of how membrane lipids act as signaling hot spots by generating distinct membrane microdomains called rafts to initiate various cellular processes and their modulation in cancer phenotypes. We elucidate tangible drug targets and pathways all amenable to small-molecule perturbation. Ranging from targeting membrane rafts organization/reorganization to rewiring lipid metabolism and lipid sorting in cancer, the work summarized here represents critical intervention points being attempted for lipid-based anticancer therapy and future directions.
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54
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Shah T, Krishnamachary B, Wildes F, Wijnen JP, Glunde K, Bhujwalla ZM. Molecular causes of elevated phosphoethanolamine in breast and pancreatic cancer cells. NMR IN BIOMEDICINE 2018; 31:e3936. [PMID: 29928787 PMCID: PMC6118328 DOI: 10.1002/nbm.3936] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 05/03/2023]
Abstract
Elevated phosphoethanolamine (PE) is frequently observed in MRS studies of human cancers and xenografts. The role of PE in cell survival and the molecular causes underlying this increase are, however, relatively underexplored. In this study, we investigated the roles of ethanolamine kinases (Etnk-1 and 2) and choline kinases (Chk-α and β) in contributing to increased PE in human breast and pancreatic cancer cells. We investigated the effect of silencing Etnk-1 and Etnk-2 on cell viability as a potential therapeutic strategy. Both breast and pancreatic cancer cells showed higher PE compared with their nonmalignant counterparts. We identified Etnk-1 as a major cause of the elevated PE levels in these cancer cells, with little or no contribution from Chk-α, Chk-β, or Etnk-2. The increase of PE observed in pancreatic cancer cells in culture was replicated in the corresponding tumor xenografts. Downregulation of Etnk-1 with siRNA resulted in cell cytotoxicity that correlated with PE levels in breast and pancreatic cancer cells. Etnk-1 may provide a potential therapeutic target in breast and pancreatic cancers.
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Affiliation(s)
- Tariq Shah
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Balaji Krishnamachary
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Flonne Wildes
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Jannie P. Wijnen
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Centre of Image Sciences/High field MR Research group, Radiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Kristine Glunde
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Zaver M. Bhujwalla
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Correspondence: Zaver M. Bhujwalla, PhD, Division of Cancer Imaging Research, Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Rm 208C Traylor Building, Baltimore, MD 21205, USA, Phone: +1 (410) 955 9698 | Fax: +1 (410) 614 1948,
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55
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Vance JE. Historical perspective: phosphatidylserine and phosphatidylethanolamine from the 1800s to the present. J Lipid Res 2018; 59:923-944. [PMID: 29661786 DOI: 10.1194/jlr.r084004] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/12/2018] [Indexed: 12/17/2022] Open
Abstract
This article provides a historical account of the discovery, chemistry, and biochemistry of two ubiquitous phosphoglycerolipids, phosphatidylserine (PS) and phosphatidylethanolamine (PE), including the ether lipids. In addition, the article describes the biosynthetic pathways for these phospholipids and how these pathways were elucidated. Several unique functions of PS and PE in mammalian cells in addition to their ability to define physical properties of membranes are discussed. For example, the translocation of PS from the inner to the outer leaflet of the plasma membrane of cells occurs during apoptosis and during some other specific physiological processes, and this translocation is responsible for profound life-or-death events. Moreover, mitochondrial function is severely impaired when the PE content of mitochondria is reduced below a threshold level. The discovery and implications of the existence of membrane contact sites between the endoplasmic reticulum and mitochondria and their relevance for PS and PE metabolism, as well as for mitochondrial function, are also discussed. Many of the recent advances in these fields are due to the use of isotope labeling for tracing biochemical pathways. In addition, techniques for disruption of specific genes in mice are now widely used and have provided major breakthroughs in understanding the roles and metabolism of PS and PE in vivo.
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Affiliation(s)
- Jean E Vance
- Department of Medicine and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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56
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Mioka T, Fujimura-Kamada K, Mizugaki N, Kishimoto T, Sano T, Nunome H, Williams DE, Andersen RJ, Tanaka K. Phospholipid flippases and Sfk1p, a novel regulator of phospholipid asymmetry, contribute to low permeability of the plasma membrane. Mol Biol Cell 2018. [PMID: 29540528 PMCID: PMC5935070 DOI: 10.1091/mbc.e17-04-0217] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Phospholipid flippase (type 4 P-type ATPase) plays a major role in the generation of phospholipid asymmetry in eukaryotic cell membranes. Loss of Lem3p-Dnf1/2p flippases leads to the exposure of phosphatidylserine (PS) and phosphatidylethanolamine (PE) on the cell surface in yeast, resulting in sensitivity to PS- or PE-binding peptides. We isolated Sfk1p, a conserved membrane protein in the TMEM150/FRAG1/DRAM family, as a multicopy suppressor of this sensitivity. Overexpression of SFK1 decreased PS/PE exposure in lem3Δ mutant cells. Consistent with this, lem3Δ sfk1Δ double mutant cells exposed more PS/PE than the lem3Δ mutant. Sfk1p was previously implicated in the regulation of the phosphatidylinositol-4 kinase Stt4p, but the effect of Sfk1p on PS/PE exposure in lem3Δ was independent of Stt4p. Surprisingly, Sfk1p did not facilitate phospholipid flipping but instead repressed it, even under ATP-depleted conditions. We propose that Sfk1p negatively regulates transbilayer movement of phospholipids irrespective of directions. In addition, we showed that the permeability of the plasma membrane was dramatically elevated in the lem3Δ sfk1Δ double mutant in comparison with the corresponding single mutants. Interestingly, total ergosterol was decreased in the lem3Δ sfk1Δ mutant. Our results suggest that phospholipid asymmetry is required for the maintenance of low plasma membrane permeability.
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Affiliation(s)
- Tetsuo Mioka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Konomi Fujimura-Kamada
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Nahiro Mizugaki
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Takamitsu Sano
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Hitoshi Nunome
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - David E Williams
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Raymond J Andersen
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Kazuma Tanaka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
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57
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Rybczynska AA, Boersma HH, de Jong S, Gietema JA, Noordzij W, Dierckx RAJO, Elsinga PH, van Waarde A. Avenues to molecular imaging of dying cells: Focus on cancer. Med Res Rev 2018. [PMID: 29528513 PMCID: PMC6220832 DOI: 10.1002/med.21495] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Successful treatment of cancer patients requires balancing of the dose, timing, and type of therapeutic regimen. Detection of increased cell death may serve as a predictor of the eventual therapeutic success. Imaging of cell death may thus lead to early identification of treatment responders and nonresponders, and to “patient‐tailored therapy.” Cell death in organs and tissues of the human body can be visualized, using positron emission tomography or single‐photon emission computed tomography, although unsolved problems remain concerning target selection, tracer pharmacokinetics, target‐to‐nontarget ratio, and spatial and temporal resolution of the scans. Phosphatidylserine exposure by dying cells has been the most extensively studied imaging target. However, visualization of this process with radiolabeled Annexin A5 has not become routine in the clinical setting. Classification of death modes is no longer based only on cell morphology but also on biochemistry, and apoptosis is no longer found to be the preponderant mechanism of cell death after antitumor therapy, as was earlier believed. These conceptual changes have affected radiochemical efforts. Novel probes targeting changes in membrane permeability, cytoplasmic pH, mitochondrial membrane potential, or caspase activation have recently been explored. In this review, we discuss molecular changes in tumors which can be targeted to visualize cell death and we propose promising biomarkers for future exploration.
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Affiliation(s)
- Anna A Rybczynska
- Molecular Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.,Department of Genetics, University of Groningen, Groningen, the Netherlands
| | - Hendrikus H Boersma
- Molecular Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.,Department of Clinical Pharmacy & Pharmacology, University of Groningen, Groningen, the Netherlands
| | - Steven de Jong
- Department of Medical Oncology, University of Groningen, Groningen, the Netherlands
| | - Jourik A Gietema
- Department of Medical Oncology, University of Groningen, Groningen, the Netherlands
| | - Walter Noordzij
- Molecular Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Rudi A J O Dierckx
- Molecular Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.,Department of Nuclear Medicine, Ghent University, Ghent, Belgium
| | - Philip H Elsinga
- Molecular Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Aren van Waarde
- Molecular Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
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58
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Extracellular vesicle budding is inhibited by redundant regulators of TAT-5 flippase localization and phospholipid asymmetry. Proc Natl Acad Sci U S A 2018; 115:E1127-E1136. [PMID: 29367422 PMCID: PMC5819400 DOI: 10.1073/pnas.1714085115] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells release extracellular vesicles (EVs) that mediate intercellular communication and repair damaged membranes. Despite the pleiotropic functions of EVs in vitro, their in vivo function is debated, largely because it is unclear how to induce or inhibit their formation. In particular, the mechanisms of EV release by plasma membrane budding or ectocytosis are poorly understood. We previously showed that TAT-5 phospholipid flippase activity maintains the asymmetric localization of the lipid phosphatidylethanolamine (PE) in the plasma membrane and inhibits EV budding by ectocytosis in Caenorhabditis elegans However, no proteins that inhibit ectocytosis upstream of TAT-5 were known. Here, we identify TAT-5 regulators associated with retrograde endosomal recycling: PI3Kinase VPS-34, Beclin1 homolog BEC-1, DnaJ protein RME-8, and the uncharacterized Dopey homolog PAD-1. PI3Kinase, RME-8, and semiredundant sorting nexins are required for the plasma membrane localization of TAT-5, which is important to maintain PE asymmetry and inhibit EV release. PAD-1 does not directly regulate TAT-5 localization, but is required for the lipid flipping activity of TAT-5. PAD-1 also has roles in endosomal trafficking with the GEF-like protein MON-2, which regulates PE asymmetry and EV release redundantly with sorting nexins independent of the core retromer. Thus, in addition to uncovering redundant intracellular trafficking pathways, our study identifies additional proteins that regulate EV release. This work pinpoints TAT-5 and PE as key regulators of plasma membrane budding, further supporting the model that PE externalization drives ectocytosis.
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59
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Early endosome as a pathogenic target for antiphosphatidylethanolamine antibodies. Proc Natl Acad Sci U S A 2017; 114:13798-13803. [PMID: 29229837 DOI: 10.1073/pnas.1714027115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Phosphatidylethanolamine (PE) is a major phospholipid species with important roles in membrane trafficking and reorganization. Accumulating clinical data indicate that the presence of circulating antibodies against PE is positively correlated with the symptoms of antiphospholipid syndromes (APS), including thrombosis and repeated pregnancy loss. However, PE is generally sequestered inside a normal resting cell, and the mechanism by which circulating anti-PE antibodies access cellular PE remains unknown. The studies presented here were conducted with synthetic PE-binding agents, plasma samples from patients with anti-PE autoimmunity, and purified anti-PE antibodies. The results suggest that the cellular vulnerability to anti-PE antibodies may be mediated by the binding of PE molecules in the membrane of the early endosome. Endosomal PE binding led to functional changes in endothelial cells, including declines in proliferation and increases in the production of reactive oxygen species, as well as the expression of inflammatory molecules. Collectively, our findings provide insight into the etiology of anti-PE autoimmunity and, because endosomes are of central importance in almost all types of cells, could have important implications for a wide range of biological processes.
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60
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Gopi M, Vanisree AJ. Attenuated levels of phospholipids in the striatum of rats infused with rotenone causing hemiparkinsonism as detected by simple dye-lipid complex. IBRO Rep 2017; 3:1-8. [PMID: 30135937 PMCID: PMC6084873 DOI: 10.1016/j.ibror.2017.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 04/24/2017] [Accepted: 06/10/2017] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD), a progressive neurodegeneration, is characterized by loss of dopaminergic neurons in the substantia nigra (SN) and loss of motor co-ordination. Impaired metabolism of major lipids such as phospholipids which play regulatory roles in cellular functions and signaling has been implicated in the pathology of PD. We aim to investigate the striatal phospholipids (PLs) in hemiparkinsonism infused by rotenone in rats. As there are no cost-effective modes of PL, we have utilized dye-lipid complex technique for the first time in PD models for screening and also for semi-quantifying (individually) the levels of the deregulated PL in brain samples. Rats were divided into 2 groups: i. control and ii. ROT-infused which received intracranial injection of Rotenone (6 μg/μl; flow rate 0.2 μl/min). At the end of experimental period of 14 days, the striatum was dissected out for the analyses of PLs. Dye-based detection of PL and two-dimensional thin-layer chromatographic analyses of PL were performed. Detection of dye-PL complex was possible for phosphatidyl choline (PC), phosphatidyl inositol (PI), and spingomyelin (SM) (but not for phosphatidyl ethanolamine-PE) using dyes viz victoria blue B, toluidine blue and ammonium ferrothiocyanate, respectively. Two-dimensional analyses of phospholipids confirmed the dye-PL complex and depicted significant reduction (p < 0.05) on semi-quantitative assessment, in the striatum of control and hemiparkinsonic rats. We suggest a low level of PLs esp of PI in striatum of rats using a simple dye-detection that was validated by HR-LCMS. The finding implies that a critical role is being played by these PLs (PC, PI and SM) mainly PI (p < 0.001), in rotenone infused hemiparkinsonism, thus deserving wider but simpler investigations to detect and identify their role in parkinsonism.
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Key Words
- AD, Alzheimer's disease
- AFTC, Ammonium ferrothiocyanate
- ANSA, 1 Amino-2 naphthol-4 sulfonic acid
- DA, Dopaminergic neuron
- DMSO, Dimethyl sulfoxide
- Dye-lipid complex
- ESI, Electrospray ionization
- HCl, Hydrochloric acid
- HRLCMS, High resolution liquid chromatography–mass spectrometry
- MRM, Multiple reaction monitor
- MS, Mass spectrometry
- NM, Neuromelanin
- Na.EDTA, Sodium Ethylenediaminetetraacetic acid
- NaCl, Sodium chloride
- PC, Phosphatidyl choline
- PD, Parkinson's disease
- PE, Phosphatidyl ethanolamine
- PI(3,5)P2, Phosphatidylinositol 3,5-bisphosphate
- PI, Phosphoinositide
- PLs, Phospholipids
- Parkinson's disease
- Phospholipids
- PtdIns(3,4,5)P3, Phosphatidylinositol 3,4,5-trisphosphate
- PtdIns(4,5)P2, Phosphatidylinositol 4,5-bisphosphate
- PtdIns5P, Phosphatidylinositol 5-phosphate
- ROT, Rotenone
- Rotenone
- SM, Spingomyelin
- SNpc, Substantia nigra pars compacta
- Striatum
- TB, Toluidine blue dye
- TBAHS, tetrabutyl ammonium hydrogen sulphate
- TEM, Transmission electron microscopy
- TLC, Thin layer chromatography
- VBB, Victoria blue-B dye
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61
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Furse S, Shearman GC. Do lipids shape the eukaryotic cell cycle? Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:9-19. [PMID: 28964796 DOI: 10.1016/j.bbalip.2017.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/07/2017] [Accepted: 09/24/2017] [Indexed: 10/18/2022]
Abstract
Successful passage through the cell cycle presents a number of structural challenges to the cell. Inceptive studies carried out in the last five years have produced clear evidence of modulations in the lipid profile (sometimes referred to as the lipidome) of eukaryotes as a function of the cell cycle. This mounting body of evidence indicates that lipids play key roles in the structural transformations seen across the cycle. The accumulation of this evidence coincides with a revolution in our understanding of how lipid composition regulates a plethora of biological processes ranging from protein activity through to cellular signalling and membrane compartmentalisation. In this review, we discuss evidence from biological, chemical and physical studies of the lipid fraction across the cell cycle that demonstrate that lipids are well-developed cellular components at the heart of the biological machinery responsible for managing progress through the cell cycle. Furthermore, we discuss the mechanisms by which this careful control is exercised.
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Affiliation(s)
- Samuel Furse
- NucReg Research Programme, Molekylærbiologisk institutt, Unversitetet i Bergen, Thormøhlens gate 55, 5008, Bergen, Norway; Core Metabolomics and Lipidomics Laboratory, Department of Biochemistry, University of Cambridge, c/o Level 4, Pathology Building, Addenbrookes Hospital, Cambridge, CB2 0QQ, United Kingdom..
| | - Gemma C Shearman
- Faculty of Science, Engineering and Computing, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, United Kingdom
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62
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Li Y, Yan J, Ding W, Chen Y, Pack LM, Chen T. Genotoxicity and gene expression analyses of liver and lung tissues of mice treated with titanium dioxide nanoparticles. Mutagenesis 2017; 32:33-46. [PMID: 28011748 DOI: 10.1093/mutage/gew065] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Titanium dioxide nanoparticles (TiO2 NPs) are used in paints, plastics, papers, inks, foods, toothpaste, pharmaceuticals and cosmetics. However, TiO2 NPs cause inflammation, pulmonary damage, fibrosis and lung tumours in animals and are possibly carcinogenic to humans. Although there are a large number of studies on the toxicities of TiO2 NPs, the data are inconclusive and the mechanisms underlying the toxicity are not clear. In this study, we used the Comet assay to evaluate genotoxicity and whole-genome microarray technology to analyse gene expression pattern in vivo to explore the possible mechanisms for toxicity and genotoxicity of TiO2 NPs. Mice were treated with three daily i.p. injections of 50 mg/kg 10 nm anatase TiO2 NPs and sacrificed 4 h after the last treatment. The livers and lungs were then isolated for the Comet assay and whole genome microarray analysis of gene expression. The NPs were heavily accumulated in liver and lung tissues. However, the treatment was positive for DNA strand breaks only in liver measured with the standard Comet assay, but positive for oxidative DNA adducts in both liver and lung as determined with the enzyme-modified Comet assay. The genotoxicity results suggest that DNA damage mainly resulted from oxidised nucleotides. Gene expression profiles and functional analyses revealed that exposure to TiO2 NPs triggered distinct gene expression patterns in both liver and lung tissues. The gene expression results suggest that TiO2 NPs impair DNA and cells by interrupting metabolic homeostasis in liver and by inducing oxidative stress, inflammatory responses and apoptosis in lung. These findings have broad implications when evaluating the safety of TiO2 NPs used in numerous consumer products.
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Affiliation(s)
- Yan Li
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR 72079, USA.,Covance Laboratories, Inc., Greenfield, IN 46140, USA and
| | - Jian Yan
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR 72079, USA
| | - Wei Ding
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR 72079, USA
| | - Ying Chen
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR 72079, USA
| | - Lindsay M Pack
- Nanotechnology Core Facility, National Center for Toxicological Research, Jefferson, AR 72079, USA.,Present address: Arkansas Children's Nutrition Center, Arkansas Children's Hospital, Little Rock, AR 72202, USA
| | - Tao Chen
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR 72079, USA,
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63
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Multitiered and Cooperative Surveillance of Mitochondrial Phosphatidylserine Decarboxylase 1. Mol Cell Biol 2017; 37:MCB.00049-17. [PMID: 28606933 DOI: 10.1128/mcb.00049-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/08/2017] [Indexed: 11/20/2022] Open
Abstract
Phosphatidylserine decarboxylase 1 (Psd1p), an ancient enzyme that converts phosphatidylserine to phosphatidylethanolamine in the inner mitochondrial membrane, must undergo an autocatalytic self-processing event to gain activity. Autocatalysis severs the protein into a large membrane-anchored β subunit that noncovalently associates with the small α subunit on the intermembrane space side of the inner membrane. Here, we determined that a temperature sensitive (ts) PSD1 allele is autocatalytically impaired and that its fidelity is closely monitored throughout its life cycle by multiple mitochondrial quality control proteases. Interestingly, the proteases involved in resolving misfolded Psd1ts vary depending on its autocatalytic status. Specifically, the degradation of a Psd1ts precursor unable to undergo autocatalysis requires the unprecedented cooperative and sequential actions of two inner membrane proteases, Oma1p and Yme1p. In contrast, upon heat exposure postautocatalysis, Psd1ts β subunits accumulate in protein aggregates that are resolved by Yme1p acting alone, while the released α subunit is degraded in parallel by an unidentified protease. Importantly, the stability of endogenous Psd1p is also influenced by Yme1p. We conclude that Psd1p, the key enzyme required for the mitochondrial pathway of phosphatidylethanolamine production, is closely monitored at several levels and by multiple mitochondrial quality control mechanisms present in the intermembrane space.
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64
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Phosphatidylethanolamine targeting for cell death imaging in early treatment response evaluation and disease diagnosis. Apoptosis 2017. [DOI: 10.1007/s10495-017-1384-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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65
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Farine L, Jelk J, Choi J, Voelker DR, Nunes J, Smith TK, Bütikofer P. Phosphatidylserine synthase 2 and phosphatidylserine decarboxylase are essential for aminophospholipid synthesis in Trypanosoma brucei. Mol Microbiol 2017; 104:412-427. [PMID: 28142188 PMCID: PMC5413845 DOI: 10.1111/mmi.13637] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2017] [Indexed: 01/09/2023]
Abstract
Phosphatidylethanolamine (PE) and phosphatidylserine (PS) are ubiquitously expressed and metabolically interconnected glycerophospholipids in eukaryotes and prokaryotes. In Trypanosoma brucei, PE synthesis has been shown to occur mainly via the Kennedy pathway, one of the three routes leading to PE synthesis in eukaryotes, while PS synthesis has not been studied experimentally. We now reveal the importance of T. brucei PS synthase 2 (TbPSS2) and T. brucei PS decarboxylase (TbPSD), two key enzymes involved in aminophospholipid synthesis, for trypanosome viability. By using tetracycline-inducible down-regulation of gene expression and in vivo and in vitro metabolic labeling, we found that TbPSS2 (i) is necessary for normal growth of procyclic trypanosomes, (ii) localizes to the endoplasmic reticulum and (iii) represents the unique route for PS formation in T. brucei. In addition, we identified TbPSD as type I PS decarboxylase in the mitochondrion and found that it is processed proteolytically at a WGSS cleavage site into a heterodimer. Down-regulation of TbPSD expression affected mitochondrial integrity in both procyclic and bloodstream form trypanosomes, decreased ATP production via oxidative phosphorylation in procyclic form and affected parasite growth.
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Affiliation(s)
- Luce Farine
- Institute of Biochemistry and Molecular MedicineUniversity of BernBern3012Switzerland
| | - Jennifer Jelk
- Institute of Biochemistry and Molecular MedicineUniversity of BernBern3012Switzerland
| | - Jae‐Yeon Choi
- Department of MedicineNational Jewish HealthDenverCO80206USA
| | | | - Jon Nunes
- Biomedical Sciences Research ComplexUniversity of St. AndrewsSt. AndrewsScotland
| | - Terry K. Smith
- Biomedical Sciences Research ComplexUniversity of St. AndrewsSt. AndrewsScotland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular MedicineUniversity of BernBern3012Switzerland
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66
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Phosphatidylethanolamine dynamics are required for osteoclast fusion. Sci Rep 2017; 7:46715. [PMID: 28436434 PMCID: PMC5402267 DOI: 10.1038/srep46715] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/23/2017] [Indexed: 11/08/2022] Open
Abstract
Osteoclasts, responsible for bone resorption, are multinucleated cells formed by cell-cell fusion of mononuclear pre-osteoclasts. Although osteoclast fusion is a pivotal step for osteoclastogenesis, little is known about the mechanism involved. To clarify the underlying process, we investigated dynamics of membrane phospholipids during osteoclastogenesis in vitro. We found that the cellular content of phospholipids, phosphatidylethanolamine (PE) in particular, was increased during osteoclast differentiation. Furthermore, PE was greatly increased in the outer leaflet of the plasma membrane bilayer during osteoclastogenesis, being concentrated in filopodia involved in cell-cell fusion. Immobilisation of the cell surface PE blocked osteoclast fusion, revealing the importance of PE abundance and distribution. To identify the molecules responsible for these PE dynamics, we screened a wide array of lipid-related genes by quantitative PCR and shRNA-mediated knockdown. Among them, a PE-biosynthetic enzyme, acyl-CoA:lysophosphatidylethanolamine acyltransferase 2 (LPEAT2), and two ATP-binding cassette (ABC) transporters, ABCB4 and ABCG1, were markedly increased during osteoclastogenesis, and their knockdown in pre-osteoclasts led to reduction in PE exposure on the cell surface and subsequent osteoclast fusion. These findings demonstrate that the PE dynamics play an essential role in osteoclast fusion, in which LPEAT2, ABCB4 and ABCG1 are key players for PE biosynthesis and redistribution.
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67
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Tan LTH, Chan KG, Pusparajah P, Lee WL, Chuah LH, Khan TM, Lee LH, Goh BH. Targeting Membrane Lipid a Potential Cancer Cure? Front Pharmacol 2017; 8:12. [PMID: 28167913 PMCID: PMC5253362 DOI: 10.3389/fphar.2017.00012] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/06/2017] [Indexed: 12/21/2022] Open
Abstract
Cancer mortality and morbidity is projected to increase significantly over the next few decades. Current chemotherapeutic strategies have significant limitations, and there is great interest in seeking novel therapies which are capable of specifically targeting cancer cells. Given that fundamental differences exist between the cellular membranes of healthy cells and tumor cells, novel therapies based on targeting membrane lipids in cancer cells is a promising approach that deserves attention in the field of anticancer drug development. Phosphatidylethanolamine (PE), a lipid membrane component which exists only in the inner leaflet of cell membrane under normal circumstances, has increased surface representation on the outer membrane of tumor cells with disrupted membrane asymmetry. PE thus represents a potential chemotherapeutic target as the higher exposure of PE on the membrane surface of cancer cells. This feature as well as a high degree of expression of PE on endothelial cells in tumor vasculature, makes PE an attractive molecular target for future cancer interventions. There have already been several small molecules and membrane-active peptides identified which bind specifically to the PE molecules on the cancer cell membrane, subsequently inducing membrane disruption leading to cell lysis. This approach opens up a new front in the battle against cancer, and is of particular interest as it may be a strategy that may be prove effective against tumors that respond poorly to current chemotherapeutic agents. We aim to highlight the evidence suggesting that PE is a strong candidate to be explored as a potential molecular target for membrane targeted novel anticancer therapy.
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Affiliation(s)
- Loh Teng-Hern Tan
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University Malaysia Bandar Sunway, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Priyia Pusparajah
- Biomedical Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia Bandar Sunway, Malaysia
| | - Wai-Leng Lee
- School of Science, Monash University Malaysia Selangor, Malaysia
| | - Lay-Hong Chuah
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University Malaysia Bandar Sunway, Malaysia
| | - Tahir Mehmood Khan
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia; Department of Pharmacy, Abasyn University PeshawarPeshawar, Pakistan
| | - Learn-Han Lee
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia; Center of Health Outcomes Research and Therapeutic Safety, School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
| | - Bey-Hing Goh
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia; Center of Health Outcomes Research and Therapeutic Safety, School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
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68
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Fujimoto T, Parmryd I. Interleaflet Coupling, Pinning, and Leaflet Asymmetry-Major Players in Plasma Membrane Nanodomain Formation. Front Cell Dev Biol 2017; 4:155. [PMID: 28119914 PMCID: PMC5222840 DOI: 10.3389/fcell.2016.00155] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 12/27/2016] [Indexed: 01/26/2023] Open
Abstract
The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence.
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Affiliation(s)
- Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Ingela Parmryd
- Science for Life Laboratory, Medical Cell Biology, Uppsala University Uppsala, Sweden
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69
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Probing phosphoethanolamine-containing lipids in membranes with duramycin/cinnamycin and aegerolysin proteins. Biochimie 2016; 130:81-90. [DOI: 10.1016/j.biochi.2016.09.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023]
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70
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Beer KB, Wehman AM. Mechanisms and functions of extracellular vesicle release in vivo-What we can learn from flies and worms. Cell Adh Migr 2016; 11:135-150. [PMID: 27689411 PMCID: PMC5351733 DOI: 10.1080/19336918.2016.1236899] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cells from bacteria to man release extracellular vesicles (EVs) that contain signaling molecules like proteins, lipids, and nucleic acids. The content, formation, and signaling roles of these conserved vesicles are diverse, but the physiological relevance of EV signaling in vivo is still debated. Studies in classical genetic model organisms like C. elegans and Drosophila have begun to reveal the developmental and behavioral roles for EVs. In this review, we discuss the emerging evidence for the in vivo signaling roles of EVs. Significant effort has also been made to understand the mechanisms behind the formation and release of EVs, specifically of exosomes derived from exocytosis of multivesicular bodies and of microvesicles derived from plasma membrane budding called ectocytosis. In this review, we detail the impact of flies and worms on understanding the proteins and lipids involved in EV biogenesis and highlight the open questions in the field.
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Affiliation(s)
- Katharina B Beer
- a Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg , Würzburg , Germany
| | - Ann Marie Wehman
- a Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg , Würzburg , Germany
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71
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Abstract
Duramycin, through binding with phosphatidylethanolamine (PE), has shown potential to be an effective antitumour agent. However, its mode of action in relation to tumour cells is not fully understood. PE expression on the surface of a panel of cancer cell lines was analysed using duramycin and subsequent antibody labelling, and then analysed by flow cytometry. Cell viability was also assessed by flow cytometry using annexin V and propidium iodide. Calcium ion (Ca) release by tumour cells in response to duramycin was determined by spectrofluorometry following incubation with Fluo-3, AM. Confocal microscopy was performed on the cancer cell line AsPC-1 to assess real-time cell response to duramycin treatment. Duramycin could detect cell surface PE expression on all 15 cancer cell lines screened, which was shown to be duramycin concentration dependent. However, higher concentrations induced necrotic cell death. Duramycin induced calcium ion (Ca) release from the cancer cell lines also in a concentration-dependent and time-dependent manner. Confocal microscopy showed an influx of propidium iodide into the cells over time and induced morphological changes. Duramycin induces Ca release from cancer cell lines in a time-dependent and concentration-dependent manner.
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72
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Takar M, Wu Y, Graham TR. The Essential Neo1 Protein from Budding Yeast Plays a Role in Establishing Aminophospholipid Asymmetry of the Plasma Membrane. J Biol Chem 2016; 291:15727-39. [PMID: 27235400 DOI: 10.1074/jbc.m115.686253] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic organisms typically express multiple type IV P-type ATPases (P4-ATPases), which establish plasma membrane asymmetry by flipping specific phospholipids from the exofacial to the cytosolic leaflet. Saccharomyces cerevisiae, for example, expresses five P4-ATPases, including Neo1, Drs2, Dnf1, Dnf2, and Dnf3. Neo1 is thought to be a phospholipid flippase, although there is currently no experimental evidence that Neo1 catalyzes this activity or helps establish membrane asymmetry. Here, we use temperature-conditional alleles (neo1(ts)) to test whether Neo1 deficiency leads to loss of plasma membrane asymmetry. Wild-type (WT) yeast normally restrict most of the phosphatidylserine (PS) and phosphatidylethanolamine (PE) to the inner cytosolic leaflet of the plasma membrane. However, the neo1-1(ts) and neo1-2(ts) mutants display a loss of PS and PE asymmetry at permissive growth temperatures as measured by hypersensitivity to pore-forming toxins that target PS (papuamide A) or PE (duramycin) exposed in the extracellular leaflet. When shifted to a semi-permissive growth temperature, the neo1-1(ts) mutant became extremely hypersensitive to duramycin, although the sensitivity to papuamide A was unchanged, indicating preferential exposure of PE. This loss of asymmetry occurs despite the presence of other flippases that flip PS and/or PE. Even when overexpressed, Drs2 and Dnf1 were unable to correct the loss of asymmetry caused by neo1(ts) However, modest overexpression of Neo1 weakly suppressed loss of membrane asymmetry caused by drs2Δ with a more significant correction of PE asymmetry than PS. These results indicate that Neo1 plays an important role in establishing PS and PE plasma membrane asymmetry in budding yeast.
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Affiliation(s)
- Mehmet Takar
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Yuantai Wu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Todd R Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
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73
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Sankhagowit S, Lee EY, Wong GCL, Malmstadt N. Oxidation of Membrane Curvature-Regulating Phosphatidylethanolamine Lipid Results in Formation of Bilayer and Cubic Structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2450-7. [PMID: 26866900 PMCID: PMC6559366 DOI: 10.1021/acs.langmuir.5b04332] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Oxidation is associated with conditions related to chronic inflammations and aging. Cubic structures have been observed in the smooth endoplasmic reticulum and mitochondrial membranes of cells under oxidative stress (e.g., tumor cells and virus-infected cells). It has been previously suspected that oxidation can result in the rearrangement of lipids from a fluid lamellar phase to a cubic structure in organelles containing membranes enriched with amphiphiles that have nonzero intrinsic curvature, such as phosphatidylethanolamine (PE) and cardiolipin. This study focuses on the oxidation of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), a lipid that natively forms an inverted hexagonal phase at physiological conditions. The oxidized samples contain an approximately 3:2 molar ratio of nonoxidized to oxidized DOPE. Optical microscopy images collected during the hydration of this mixture from a dried film suggest that the system evolves into a coexistence of a stable fluid lamellar phase and transient square lattice structures with unit cell sizes of 500-600 nm. Small-angle X-ray scattering of the same lipid mixture yielded a body-centered Im3m cubic phase with the lattice parameter of 14.04 nm. On average, the effective packing parameter of the oxidized DOPE species was estimated to be 0.657 ± 0.069 (standard deviation). This suggests that the oxidation of PE leads to a group of species with inverted molecular intrinsic curvature. Oxidation can create amphiphilic subpopulations that potently impact the integrity of the membrane, since negative Gaussian curvature intrinsic to cubic phases can enable membrane destabilization processes.
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Affiliation(s)
- Shalene Sankhagowit
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - Ernest Y. Lee
- Bioengineering Department, Chemistry & Biochemistry Department, California Nano Systems Institute, University of California, Los Angeles, California 90095, United States
| | - Gerard C. L. Wong
- Bioengineering Department, Chemistry & Biochemistry Department, California Nano Systems Institute, University of California, Los Angeles, California 90095, United States
| | - Noah Malmstadt
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
- Corresponding Author. Phone: +1 213 821 2034. Fax: +1 213 740 1056
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74
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Murate M, Kobayashi T. Revisiting transbilayer distribution of lipids in the plasma membrane. Chem Phys Lipids 2016; 194:58-71. [DOI: 10.1016/j.chemphyslip.2015.08.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 12/22/2022]
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75
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Fujimoto T, Parmryd I. Interleaflet Coupling, Pinning, and Leaflet Asymmetry-Major Players in Plasma Membrane Nanodomain Formation. Front Cell Dev Biol 2016. [PMID: 28119914 DOI: 10.3389/fcell.2016.0015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence.
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Affiliation(s)
- Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Ingela Parmryd
- Science for Life Laboratory, Medical Cell Biology, Uppsala University Uppsala, Sweden
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76
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Hsu JF, Hsieh PY, Hsu HY, Shigeto S. When cells divide: Label-free multimodal spectral imaging for exploratory molecular investigation of living cells during cytokinesis. Sci Rep 2015; 5:17541. [PMID: 26632877 PMCID: PMC4668386 DOI: 10.1038/srep17541] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/02/2015] [Indexed: 12/23/2022] Open
Abstract
In vivo, molecular-level investigation of cytokinesis, the climax of the cell cycle, not only deepens our understanding of how life continues, but it will also open up new possibilities of diagnosis/prognosis of cancer cells. Although fluorescence-based methods have been widely employed to address this challenge, they require a fluorophore to be designed for a specific known biomolecule and introduced into the cell. Here, we present a label-free spectral imaging approach based on multivariate curve resolution analysis of Raman hyperspectral data that enables exploratory untargeted studies of mammalian cell cytokinesis. We derived intrinsic vibrational spectra and intracellular distributions of major biomolecular components (lipids and proteins) in dividing and nondividing human colon cancer cells. In addition, we discovered an unusual autofluorescent lipid component that appears predominantly in the vicinity of the cleavage furrow during cytokinesis. This autofluorescence signal could be utilized as an endogenous probe for monitoring and visualizing cytokinesis in vivo.
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Affiliation(s)
- Jen-Fang Hsu
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
| | - Pei-Ying Hsieh
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
| | - Hsin-Yun Hsu
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
| | - Shinsuke Shigeto
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
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77
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Calzada E, Onguka O, Claypool SM. Phosphatidylethanolamine Metabolism in Health and Disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 321:29-88. [PMID: 26811286 DOI: 10.1016/bs.ircmb.2015.10.001] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Phosphatidylethanolamine (PE) is the second most abundant glycerophospholipid in eukaryotic cells. The existence of four only partially redundant biochemical pathways that produce PE, highlights the importance of this essential phospholipid. The CDP-ethanolamine and phosphatidylserine decarboxylase pathways occur in different subcellular compartments and are the main sources of PE in cells. Mammalian development fails upon ablation of either pathway. Once made, PE has diverse cellular functions that include serving as a precursor for phosphatidylcholine and a substrate for important posttranslational modifications, influencing membrane topology, and promoting cell and organelle membrane fusion, oxidative phosphorylation, mitochondrial biogenesis, and autophagy. The importance of PE metabolism in mammalian health has recently emerged following its association with Alzheimer's disease, Parkinson's disease, nonalcoholic liver disease, and the virulence of certain pathogenic organisms.
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Affiliation(s)
- Elizabeth Calzada
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ouma Onguka
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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78
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Arai Y, Sampaio JL, Wilsch-Bräuninger M, Ettinger AW, Haffner C, Huttner WB. Lipidome of midbody released from neural stem and progenitor cells during mammalian cortical neurogenesis. Front Cell Neurosci 2015; 9:325. [PMID: 26379497 PMCID: PMC4551859 DOI: 10.3389/fncel.2015.00325] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/06/2015] [Indexed: 01/24/2023] Open
Abstract
Midbody release from proliferative neural progenitor cells is tightly associated with the neuronal commitment of neural progenitor cells during the progression of neurogenesis in the mammalian cerebral cortex. While the central portion of the midbody, a cytoplasmic bridge between nascent daughter cells, is engulfed by one of the daughter cell by most cells in vitro, it is shown to be released into the extracellular cerebrospinal fluid (CF) in vivo in mouse embryos. Several proteins have been involved in midbody release; however, few studies have addressed the participation of the plasma membrane's lipids in this process. Here, we show by Shotgun Lipidomic analysis that phosphatydylserine (PS), among other lipids, is enriched in the released midbodies compared to lipoparticles and cellular membranes, both collected from the CF of the developing mouse embryos. Moreover, the developing mouse embryo neural progenitor cells released two distinct types of midbodies carrying either internalized PS or externalized PS on their membrane. This strongly suggests that phagocytosis and an alternative fate of released midbodies exists. HeLa cells, which are known to mainly engulf the midbody show almost no PS exposure, if any, on the outer leaflet of the midbody membrane. These results point toward that PS exposure might be involved in the selection of recipients of released midbodies, either to be engulfed by daughter cells or phagocytosed by non-daughter cells or another cell type in the developing cerebral cortex.
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Affiliation(s)
- Yoko Arai
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany
| | - Julio L Sampaio
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany
| | | | - Andreas W Ettinger
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany
| | - Christiane Haffner
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany
| | - Wieland B Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany
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79
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Chiba M, Miyazaki M, Ishiwata S. Quantitative analysis of the lamellarity of giant liposomes prepared by the inverted emulsion method. Biophys J 2015; 107:346-354. [PMID: 25028876 DOI: 10.1016/j.bpj.2014.05.039] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/29/2014] [Indexed: 11/26/2022] Open
Abstract
The inverted emulsion method is used to prepare giant liposomes by pushing water-in-oil droplets through the oil/water interface into an aqueous medium. Due to the high encapsulation efficiency of proteins under physiological conditions and the simplicity of the protocol, it has been widely used to prepare various cell models. However, the lamellarity of liposomes prepared by this method has not been evaluated quantitatively. Here, we prepared liposomes that were partially stained with a fluorescent dye, and analyzed their fluorescence intensity under an epifluorescence microscope. The fluorescence intensities of the membranes of individual liposomes were plotted against their diameter. The plots showed discrete distributions, which were classified into several groups. The group with the lowest fluorescence intensity was determined to be unilamellar by monitoring the exchangeability of the inner and the outer solutions of the liposomes in the presence of the pore-forming toxin α-hemolysin. Increasing the lipid concentration dissolved in oil increased the number of liposomes ∼100 times. However, almost all the liposomes were unilamellar even at saturating lipid concentrations. We also investigated the effects of lipid composition and liposome content, such as highly concentrated actin filaments and Xenopus egg extracts, on the lamellarity of the liposomes. Remarkably, over 90% of the liposomes were unilamellar under all conditions examined. We conclude that the inverted emulsion method can be used to efficiently prepare giant unilamellar liposomes and is useful for designing cell models.
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Affiliation(s)
- Masataka Chiba
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Makito Miyazaki
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan; Waseda Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore.
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80
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Development of a Novel Tetravalent Synthetic Peptide That Binds to Phosphatidic Acid. PLoS One 2015; 10:e0131668. [PMID: 26147860 PMCID: PMC4493020 DOI: 10.1371/journal.pone.0131668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 06/05/2015] [Indexed: 01/04/2023] Open
Abstract
We employed a multivalent peptide-library screening technique to identify a peptide motif that binds to phosphatidic acid (PA), but not to other phospholipids such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). A tetravalent peptide with the sequence motif of MARWHRHHH, designated as PAB-TP (phosphatidic acid-binding tetravalent peptide), was shown to bind as low as 1 mol% of PA in the bilayer membrane composed of PC and cholesterol. Kinetic analysis of the interaction between PAB-TP and the membranes containing 10 mol% of PA showed that PAB-TP associated with PA with a low dissociation constant of KD = 38 ± 5 nM. Coexistence of cholesterol or PE with PA in the membrane enhanced the PAB-TP binding to PA by increasing the ionization of the phosphomonoester head group as well as by changing the microenvironment of PA molecules in the membrane. Amino acid replacement analysis demonstrated that the tryptophan residue at position 4 of PAB-TP was involved in the interaction with PA. Furthermore, a series of amino acid substitutions at positions 5 to 9 of PAB-TP revealed the involvement of consecutive histidine and arginine residues in recognition of the phosphomonoester head group of PA. Our results demonstrate that the recognition of PA by PAB-TP is achieved by a combination of hydrophobic, electrostatic and hydrogen-bond interactions, and that the tetravalent structure of PAB-TP contributes to the high affinity binding to PA in the membrane. The novel PA-binding tetravalent peptide PAB-TP will provide insight into the molecular mechanism underlying the recognition of PA by PA-binding proteins that are involved in various cellular events.
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81
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Kaku Y, Tsuchiya A, Kanno T, Nakano T, Nishizaki T. Diarachidonoylphosphoethanolamine induces necrosis/necroptosis of malignant pleural mesothelioma cells. Cell Signal 2015; 27:1713-9. [PMID: 26004138 DOI: 10.1016/j.cellsig.2015.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/24/2015] [Accepted: 05/05/2015] [Indexed: 11/15/2022]
Abstract
The present study investigated 1,2-diarachidonoyl-sn-glycero-3-phosphoethanolamine (DAPE)-induced cell death in malignant pleural mesothelioma (MPM) cells. DAPE reduced cell viability in NCI-H28, NCI-H2052, NCI-H2452, and MSTO-211H MPM cell lines in a concentration (1-100μM)-dependent manner. In the flow cytometry using propidium iodide (PI) and annexin V (AV), DAPE significantly increased the population of PI-positive and AV-negative cells, corresponding to primary necrosis, and that of PI-positive and AV-positive cells, corresponding to late apoptosis/secondary necrosis, in NCI-H28 cells. DAPE-induced reduction of NCI-H28 cell viability was partially inhibited by necrostatin-1, an inhibitor of RIP1 kinase to induce necroptosis, or knocking-down RIP1. DAPE generated reactive oxygen species (ROS) followed by disruption of mitochondrial membrane potentials in NCI-H28 cells. DAPE-induced mitochondrial damage was attenuated by cyclosporin A, an inhibitor of cyclophilin D (CypD). DAPE did not affect expression and mitochondrial localization of p53 protein in NCI-H28 cells. DAPE significantly decreased intracellular ATP concentrations in NCI-H28 cells. Overall, the results of the present study indicate that DAPE induces necroptosis and necrosis of MPM cells; the former is mediated by RIP1 kinase and the latter is caused by generating ROS and opening CypD-dependent mitochondrial permeability transition pore, to reduce intracellular ATP concentrations.
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Affiliation(s)
- Yoshiko Kaku
- Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Ayako Tsuchiya
- Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Takeshi Kanno
- Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Takashi Nakano
- Division of Respiratory Medicine, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya 663-8501, Japan
| | - Tomoyuki Nishizaki
- Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan.
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82
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Sakuma Y, Imai M. From vesicles to protocells: the roles of amphiphilic molecules. Life (Basel) 2015; 5:651-75. [PMID: 25738256 PMCID: PMC4390873 DOI: 10.3390/life5010651] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 02/11/2015] [Accepted: 02/24/2015] [Indexed: 02/05/2023] Open
Abstract
It is very challenging to construct protocells from molecular assemblies. An important step in this challenge is the achievement of vesicle dynamics that are relevant to cellular functions, such as membrane trafficking and self-reproduction, using amphiphilic molecules. Soft matter physics will play an important role in the development of vesicles that have these functions. Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation. This achievement will elucidate the pathway from molecular assembly to cellular life.
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Affiliation(s)
- Yuka Sakuma
- Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan.
| | - Masayuki Imai
- Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan.
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83
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Waiczies S, Lepore S, Sydow K, Drechsler S, Ku MC, Martin C, Lorenz D, Schütz I, Reimann HM, Purfürst B, Dieringer MA, Waiczies H, Dathe M, Pohlmann A, Niendorf T. Anchoring dipalmitoyl phosphoethanolamine to nanoparticles boosts cellular uptake and fluorine-19 magnetic resonance signal. Sci Rep 2015; 5:8427. [PMID: 25673047 PMCID: PMC5389132 DOI: 10.1038/srep08427] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/15/2015] [Indexed: 01/19/2023] Open
Abstract
Magnetic resonance (MR) methods to detect and quantify fluorine (19F) nuclei provide the opportunity to study the fate of cellular transplants in vivo. Cells are typically labeled with 19F nanoparticles, introduced into living organisms and tracked by 19F MR methods. Background-free imaging and quantification of cell numbers are amongst the strengths of 19F MR-based cell tracking but challenges pertaining to signal sensitivity and cell detection exist. In this study we aimed to overcome these limitations by manipulating the aminophospholipid composition of 19F nanoparticles in order to promote their uptake by dendritic cells (DCs). As critical components of biological membranes, phosphatidylethanolamines (PE) were studied. Both microscopy and MR spectroscopy methods revealed a striking (at least one order of magnitude) increase in cytoplasmic uptake of 19F nanoparticles in DCs following enrichment with 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE). The impact of enriching 19F nanoparticles with PE on DC migration was also investigated. By manipulating the nanoparticle composition and as a result the cellular uptake we provide here one way of boosting 19F signal per cell in order to overcome some of the limitations related to 19F MR signal sensitivity. The boost in signal is ultimately necessary to detect and track cells in vivo.
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Affiliation(s)
- Sonia Waiczies
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Stefano Lepore
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Karl Sydow
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Susanne Drechsler
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Min-Chi Ku
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Conrad Martin
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Dorothea Lorenz
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Irene Schütz
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Henning M Reimann
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Bettina Purfürst
- Electron Microscopy Core Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Matthias A Dieringer
- 1] Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany [2] Experimental and Clinical Research Center, Berlin, Germany
| | | | - Margitta Dathe
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany
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84
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Suetsugu S, Kurisu S, Takenawa T. Dynamic shaping of cellular membranes by phospholipids and membrane-deforming proteins. Physiol Rev 2014; 94:1219-48. [PMID: 25287863 DOI: 10.1152/physrev.00040.2013] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
All cellular compartments are separated from the external environment by a membrane, which consists of a lipid bilayer. Subcellular structures, including clathrin-coated pits, caveolae, filopodia, lamellipodia, podosomes, and other intracellular membrane systems, are molded into their specific submicron-scale shapes through various mechanisms. Cells construct their micro-structures on plasma membrane and execute vital functions for life, such as cell migration, cell division, endocytosis, exocytosis, and cytoskeletal regulation. The plasma membrane, rich in anionic phospholipids, utilizes the electrostatic nature of the lipids, specifically the phosphoinositides, to form interactions with cytosolic proteins. These cytosolic proteins have three modes of interaction: 1) electrostatic interaction through unstructured polycationic regions, 2) through structured phosphoinositide-specific binding domains, and 3) through structured domains that bind the membrane without specificity for particular phospholipid. Among the structured domains, there are several that have membrane-deforming activity, which is essential for the formation of concave or convex membrane curvature. These domains include the amphipathic helix, which deforms the membrane by hemi-insertion of the helix with both hydrophobic and electrostatic interactions, and/or the BAR domain superfamily, known to use their positively charged, curved structural surface to deform membranes. Below the membrane, actin filaments support the micro-structures through interactions with several BAR proteins as well as other scaffold proteins, resulting in outward and inward membrane micro-structure formation. Here, we describe the characteristics of phospholipids, and the mechanisms utilized by phosphoinositides to regulate cellular events. We then summarize the precise mechanisms underlying the construction of membrane micro-structures and their involvements in physiological and pathological processes.
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Affiliation(s)
- Shiro Suetsugu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Shusaku Kurisu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Tadaomi Takenawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
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85
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Pavlovic Z, Singh RK, Bakovic M. A novel murine CTP:phosphoethanolamine cytidylyltransferase splice variant is a post-translational repressor and an indicator that both cytidylyltransferase domains are required for activity. Gene 2014; 543:58-68. [PMID: 24703999 DOI: 10.1016/j.gene.2014.04.005] [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] [Received: 12/10/2013] [Revised: 03/20/2014] [Accepted: 04/01/2014] [Indexed: 11/27/2022]
Abstract
CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) has an important regulatory function in biosynthesis of the membrane phospholipid phosphatidylethanolamine. We previously determined that the full-length Pcyt2α and its splice variant Pcyt2β are the main active isoforms of this enzyme. Here we report that mouse Pcyt2 could be spliced at Introns 7 and 8 to produce a unique third isoform, Pcyt2γ, in which the second cytidylyltransferase domain at the C-terminus becomes deleted. Pcyt2γ is ubiquitously expressed in embryonic and adult mouse tissues, and is the most abundant in the kidney, skeletal muscle and testis. Pcyt2γ splicing mechanism dominates over Pcyt2β exon-skipping mechanism in most examined tissues. Although Pcyt2γ maintains the N-terminal cytidylyltransferase domain as most cytidylyltransferases, the lack of the C-terminal cytidylyltransferase domain causes a complete loss of catalytic activity. However, Pcyt2γ interacts with the active isoform, Pcyt2α, and significantly reduces Pcyt2α homodimerization and activity. The inactive N-domain (H35Y, H35A) and C-domain (H244Y, H244A) mutants of Pcyt2α also reduce Pcyt2α homodimerization and activity. This study revealed the importance of both cytidylyltransferase (35)HYGH and (244)HIGH motifs for the activity of murine Pcyt2α and established that the naturally occurring splice variant Pcyt2γ has a function to restrain the enzyme activity through the formation of unproductive enzyme complexes.
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Affiliation(s)
- Zvezdan Pavlovic
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W1, Canada.
| | - Ratnesh Kumar Singh
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W1, Canada
| | - Marica Bakovic
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W1, Canada
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86
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Hishikawa D, Hashidate T, Shimizu T, Shindou H. Diversity and function of membrane glycerophospholipids generated by the remodeling pathway in mammalian cells. J Lipid Res 2014; 55:799-807. [PMID: 24646950 PMCID: PMC3995458 DOI: 10.1194/jlr.r046094] [Citation(s) in RCA: 253] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cellular membranes are composed of numerous kinds of glycerophospholipids with different combinations of polar heads at the sn-3 position and acyl moieties at the sn-1 and sn-2 positions, respectively. The glycerophospholipid compositions of different cell types, organelles, and inner/outer plasma membrane leaflets are quite diverse. The acyl moieties of glycerophospholipids synthesized in the de novo pathway are subsequently remodeled by the action of phospholipases and lysophospholipid acyltransferases. This remodeling cycle contributes to the generation of membrane glycerophospholipid diversity and the production of lipid mediators such as fatty acid derivatives and lysophospholipids. Furthermore, specific glycerophospholipid transporters are also important to organize a unique glycerophospholipid composition in each organelle. Recent progress in this field contributes to understanding how and why membrane glycerophospholipid diversity is organized and maintained.
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Affiliation(s)
- Daisuke Hishikawa
- Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
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87
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Seminal vesicle protein SVS2 is required for sperm survival in the uterus. Proc Natl Acad Sci U S A 2014; 111:4145-50. [PMID: 24591616 DOI: 10.1073/pnas.1320715111] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In mammals, sperm migrate through the female reproductive tract to reach the egg; however, our understanding of this journey is highly limited. To shed light on this process, we focused on defining the functions of seminal vesicle secretion 2 (SVS2). SVS2(-/-) male mice produced sperm but were severely subfertile, and formation of a copulatory plug to cover the female genital opening did not occur. Surprisingly, even when artificial insemination was performed with silicon as a substitute for the plug, sperm fertility in the absence of SVS2 remained severely reduced because the sperm were already dead in the uterus. Thus, our results provide evidence that the uterus induces sperm cell death and that SVS2 protects sperm from uterine attack.
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88
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Pavlovic Z, Zhu L, Pereira L, Singh RK, Cornell RB, Bakovic M. Isoform-specific and protein kinase C-mediated regulation of CTP:phosphoethanolamine cytidylyltransferase phosphorylation. J Biol Chem 2014; 289:9053-64. [PMID: 24519946 DOI: 10.1074/jbc.m113.544932] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) is the main regulatory enzyme for de novo biosynthesis of phosphatidylethanolamine by the CDP-ethanolamine pathway. There are two isoforms of Pcyt2, -α and -β; however, very little is known about their specific roles in this important metabolic pathway. We previously demonstrated increased phosphatidylethanolamine biosynthesis subsequent to elevated activity and phosphorylation of Pcyt2α and -β in MCF-7 breast cancer cells grown under conditions of serum deficiency. Mass spectroscopy analyses of Pcyt2 provided evidence for isoform-specific as well as shared phosphorylations. Pcyt2β was specifically phosphorylated at the end of the first cytidylyltransferase domain. Pcyt2α was phosphorylated within the α-specific motif that is spliced out in Pcyt2β and on two PKC consensus serine residues, Ser-215 and Ser-223. Single and double mutations of PKC consensus sites reduced Pcyt2α phosphorylation, activity, and phosphatidylethanolamine synthesis by 50-90%. The phosphorylation and activity of endogenous Pcyt2 were dramatically increased with phorbol esters and reduced by specific PKC inhibitors. In vitro translated Pcyt2α was phosphorylated by PKCα, PKCβI, and PKCβII. Pcyt2α Ser-215 was also directly phosphorylated with PKCα. Mapping of the Pcyt2α- and -β-phosphorylated sites to the solved structure of a human Pcyt2β showed that they clustered within and flanking the central linker region that connects the two catalytic domains and is a novel regulatory segment not present in other cytidylyltransferases. This study is the first to demonstrate differences in phosphorylation between Pcyt2 isoforms and to uncover the role of the PKC-regulated phosphorylation.
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Affiliation(s)
- Zvezdan Pavlovic
- From the Department of Human Health and Nutritional Sciences, University of Guelph, Ontario N1G 2W1 and
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89
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Takatori S, Mesman R, Fujimoto T. Microscopic methods to observe the distribution of lipids in the cellular membrane. Biochemistry 2014; 53:639-53. [PMID: 24460209 DOI: 10.1021/bi401598v] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane lipids not only provide the structural framework of cellular membranes but also influence protein functions in several different ways. In comparison to proteins, however, relatively little is known about distribution of membrane lipids because of the insufficiency of microscopic methods. The difficulty in studying lipid distribution results from several factors, including their unresponsiveness to chemical fixation, fast translational movement, small molecular size, and high packing density. In this Current Topic, we consider the major microscopic methods and discuss whether and to what degree of precision these methods can reveal membrane lipid distribution in situ. We highlight two fixation methods, chemical and physical, and compare the theoretical limitations to their spatial resolution. Recognizing the strengths and weaknesses of each method should help researchers interpret their microscopic results and increase our understanding of the physiological functions of lipids.
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Affiliation(s)
- Sho Takatori
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine , Nagoya 466-8550, Japan
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90
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Maekawa M, Fairn GD. Molecular probes to visualize the location, organization and dynamics of lipids. J Cell Sci 2014; 127:4801-12. [DOI: 10.1242/jcs.150524] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cellular lipids play crucial roles in the cell, including in energy storage, the formation of cellular membranes, and in signaling and vesicular trafficking. To understand the functions and characteristics of lipids within cells, various methods to image lipids have been established. In this Commentary, we discuss the four main types of molecular probes that have significantly contributed to our understanding of the cell biology of lipids. In particular, genetically encoded biosensors and antibodies will be discussed, and how they have been used extensively with traditional light and electron microscopy to determine the subcellular localization of lipids and their spatial and temporal regulation. We highlight some of the recent studies that have investigated the distribution of lipids and their ability to cluster using super-resolution and electron microscopy. We also examine methods for analyzing the movement and dynamics of lipids, including single-particle tracking (SPT), fluorescence recovery after photobleaching (FRAP) and fluorescence correlation spectroscopy (FCS). Although the combination of these lipid probes and the various microscopic techniques is very powerful, we also point out several potential caveats and limitations. Finally, we discuss the need for new probes for a variety of phospholipids and cholesterol.
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91
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Illuminating the lipidome to advance biomedical research: peptide-based probes of membrane lipids. Future Med Chem 2013; 5:947-59. [PMID: 23682570 DOI: 10.4155/fmc.13.66] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Systematic investigation of the lipidome will reveal new opportunities for disease diagnosis and intervention. However, lipidomic research has been hampered by the lack of molecular tools to track specific lipids of interest. Accumulating reports indicate lipid recognition can be achieved with properly constructed short peptides in addition to large proteins. This review summarizes the key developments of this area within the past decade. Select lantibiotic peptides present the best examples of low-molecular-weight probes of membrane lipids, displaying selectivity comparable to lipid-binding proteins. Designed peptides, through biomimetic approaches and combinational screening, have begun to demonstrate their potential for lipid tracking in cultured cells and even in living organisms. Biophysical characterization of these lipid-targeting peptides has revealed certain features critical for selective membrane binding, including preorganized scaffolds and the balance of polar and nonpolar interactions. The knowledge summarized herein should facilitate the development of molecular tools to target a variety of membrane lipids.
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92
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Abstract
Intracellular organelles, including endosomes, show differences not only in protein but also in lipid composition. It is becoming clear from the work of many laboratories that the mechanisms necessary to achieve such lipid segregation can operate at very different levels, including the membrane biophysical properties, the interactions with other lipids and proteins, and the turnover rates or distribution of metabolic enzymes. In turn, lipids can directly influence the organelle membrane properties by changing biophysical parameters and by recruiting partner effector proteins involved in protein sorting and membrane dynamics. In this review, we will discuss how lipids are sorted in endosomal membranes and how they impact on endosome functions.
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Affiliation(s)
- Christin Bissig
- Biochemistry Department, University of Geneva, 1211 Geneva 4, Switzerland
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93
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Lawrence EJ, Mandato CA. Mitochondria localize to the cleavage furrow in mammalian cytokinesis. PLoS One 2013; 8:e72886. [PMID: 23991162 PMCID: PMC3749163 DOI: 10.1371/journal.pone.0072886] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 07/21/2013] [Indexed: 01/08/2023] Open
Abstract
Mitochondria are dynamic organelles with multiple cellular functions, including ATP production, calcium buffering, and lipid biosynthesis. Several studies have shown that mitochondrial positioning is regulated by the cytoskeleton during cell division in several eukaryotic systems. However, the distribution of mitochondria during mammalian cytokinesis and whether the distribution is regulated by the cytoskeleton has not been examined. Using live spinning disk confocal microscopy and quantitative analysis of mitochondrial fluorescence intensity, we demonstrate that mitochondria are recruited to the cleavage furrow during cytokinesis in HeLa cells. After anaphase onset, the mitochondria are recruited towards the site of cleavage furrow formation, where they remain enriched as the furrow ingresses and until cytokinesis completion. Furthermore, we show that recruitment of mitochondria to the furrow occurs in multiple mammalian cells lines as well as in monopolar, bipolar, and multipolar divisions, suggesting that the mechanism of recruitment is conserved and robust. Using inhibitors of cytoskeleton dynamics, we show that the microtubule cytoskeleton, but not actin, is required to transport mitochondria to the cleavage furrow. Thus, mitochondria are specifically recruited to the cleavage furrow in a microtubule-dependent manner during mammalian cytokinesis. Two possible reasons for this could be to localize mitochondrial function to the furrow to facilitate cytokinesis and / or ensure accurate mitochondrial inheritance.
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Affiliation(s)
| | - Craig A. Mandato
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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94
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Qiao B, Lu H, Cao YX, Chen R, Yuan YJ. Phospholipid profiles ofPenicillium chrysogenumin different scales of fermentations. Eng Life Sci 2013. [DOI: 10.1002/elsc.201200139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Bin Qiao
- Key Laboratory of Systems Bioengineering, Ministry of Education; School of Chemical Engineering and Technology, Tianjin University; Tianjin P. R. China
| | - Hua Lu
- Key Laboratory of Systems Bioengineering, Ministry of Education; School of Chemical Engineering and Technology, Tianjin University; Tianjin P. R. China
- Hebei Zhongrun Pharmaceutical Co., Ltd; China, Shijiazhuang Pharmaceutical Group Co., Ltd. (CSPC); Shijiazhuang P. R. China
| | - Ying-Xiu Cao
- Key Laboratory of Systems Bioengineering, Ministry of Education; School of Chemical Engineering and Technology, Tianjin University; Tianjin P. R. China
| | - Rao Chen
- Hebei Zhongrun Pharmaceutical Co., Ltd; China, Shijiazhuang Pharmaceutical Group Co., Ltd. (CSPC); Shijiazhuang P. R. China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering, Ministry of Education; School of Chemical Engineering and Technology, Tianjin University; Tianjin P. R. China
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95
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Kagawa R, Hirano Y, Taiji M, Yasuoka K, Yasui M. Dynamic interactions of cations, water and lipids and influence on membrane fluidity. J Memb Sci 2013. [DOI: 10.1016/j.memsci.2013.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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96
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Checks and balances in membrane phospholipid class and acyl chain homeostasis, the yeast perspective. Prog Lipid Res 2013; 52:374-94. [PMID: 23631861 DOI: 10.1016/j.plipres.2013.04.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 03/28/2013] [Accepted: 04/16/2013] [Indexed: 11/24/2022]
Abstract
Glycerophospholipids are the most abundant membrane lipid constituents in most eukaryotic cells. As a consequence, phospholipid class and acyl chain homeostasis are crucial for maintaining optimal physical properties of membranes that in turn are crucial for membrane function. The topic of this review is our current understanding of membrane phospholipid homeostasis in the reference eukaryote Saccharomyces cerevisiae. After introducing the physical parameters of the membrane that are kept in optimal range, the properties of the major membrane phospholipids and their contributions to membrane structure and dynamics are summarized. Phospholipid metabolism and known mechanisms of regulation are discussed, including potential sensors for monitoring membrane physical properties. Special attention is paid to processes that maintain the phospholipid class specific molecular species profiles, and to the interplay between phospholipid class and acyl chain composition when yeast membrane lipid homeostasis is challenged. Based on the reviewed studies, molecular species selectivity of the lipid metabolic enzymes, and mass action in acyl-CoA metabolism are put forward as important intrinsic contributors to membrane lipid homeostasis.
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97
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Regulation of Phosphatidylethanolamine Homeostasis—The Critical Role of CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2). Int J Mol Sci 2013; 14:2529-50. [PMID: 23354482 PMCID: PMC3588000 DOI: 10.3390/ijms14022529] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/02/2013] [Accepted: 01/17/2013] [Indexed: 12/21/2022] Open
Abstract
Phosphatidylethanolamine (PE) is the most abundant lipid on the protoplasmatic leaflet of cellular membranes. It has a pivotal role in cellular processes such as membrane fusion, cell cycle regulation, autophagy, and apoptosis. CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) is the main regulatory enzyme in de novo biosynthesis of PE from ethanolamine and diacylglycerol by the CDP-ethanolamine Kennedy pathway. The following is a summary of the current state of knowledge on Pcyt2 and how splicing and isoform specific differences could lead to variations in functional properties in this family of enzymes. Results from the most recent studies on Pcyt2 transcriptional regulation, promoter function, autophagy, and cell growth regulation are highlighted. Recent data obtained from Pcyt2 knockout mouse models is also presented, demonstrating the essentiality of this gene in embryonic development as well as the major physiological consequences of deletion of one Pcyt2 allele. Those include development of symptoms of the metabolic syndrome such as elevated lipogenesis and lipoprotein secretion, hypertriglyceridemia, liver steatosis, obesity, and insulin resistance. The objective of this review is to elucidate the nature of Pcyt2 regulation by linking its catalytic function with the regulation of lipid and energy homeostasis.
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98
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Bohdanowicz M, Grinstein S. Role of Phospholipids in Endocytosis, Phagocytosis, and Macropinocytosis. Physiol Rev 2013; 93:69-106. [DOI: 10.1152/physrev.00002.2012] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Endocytosis, phagocytosis, and macropinocytosis are fundamental processes that enable cells to sample their environment, eliminate pathogens and apoptotic bodies, and regulate the expression of surface components. While a great deal of effort has been devoted over many years to understanding the proteins involved in these processes, the important contribution of phospholipids has only recently been appreciated. This review is an attempt to collate and analyze the rapidly emerging evidence documenting the role of phospholipids in clathrin-mediated endocytosis, phagocytosis, and macropinocytosis. A primer on phospholipid biosynthesis, catabolism, subcellular distribution, and transport is presented initially, for reference, together with general considerations of the effects of phospholipids on membrane curvature and charge. This is followed by a detailed analysis of the critical functions of phospholipids in the internalization processes and in the maturation of the resulting vesicles and vacuoles as they progress along the endo-lysosomal pathway.
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Affiliation(s)
- Michal Bohdanowicz
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
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Tasseva G, Bai HD, Davidescu M, Haromy A, Michelakis E, Vance JE. Phosphatidylethanolamine deficiency in Mammalian mitochondria impairs oxidative phosphorylation and alters mitochondrial morphology. J Biol Chem 2012; 288:4158-73. [PMID: 23250747 DOI: 10.1074/jbc.m112.434183] [Citation(s) in RCA: 250] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial dysfunction is implicated in neurodegenerative, cardiovascular, and metabolic disorders, but the role of phospholipids, particularly the nonbilayer-forming lipid phosphatidylethanolamine (PE), in mitochondrial function is poorly understood. Elimination of mitochondrial PE (mtPE) synthesis via phosphatidylserine decarboxylase in mice profoundly alters mitochondrial morphology and is embryonic lethal (Steenbergen, R., Nanowski, T. S., Beigneux, A., Kulinski, A., Young, S. G., and Vance, J. E. (2005) J. Biol. Chem. 280, 40032-40040). We now report that moderate <30% depletion of mtPE alters mitochondrial morphology and function and impairs cell growth. Acute reduction of mtPE by RNAi silencing of phosphatidylserine decarboxylase and chronic reduction of mtPE in PSB-2 cells that have only 5% of normal phosphatidylserine synthesis decreased respiratory capacity, ATP production, and activities of electron transport chain complexes (C) I and CIV but not CV. Blue native-PAGE analysis revealed defects in the organization of CI and CIV into supercomplexes in PE-deficient mitochondria, correlated with reduced amounts of CI and CIV proteins. Thus, mtPE deficiency impairs formation and/or membrane integration of respiratory supercomplexes. Despite normal or increased levels of mitochondrial fusion proteins in mtPE-deficient cells, and no reduction in mitochondrial membrane potential, mitochondria were extensively fragmented, and mitochondrial ultrastructure was grossly aberrant. In general, chronic reduction of mtPE caused more pronounced mitochondrial defects than did acute mtPE depletion. The functional and morphological changes in PSB-2 cells were largely reversed by normalization of mtPE content by supplementation with lyso-PE, a mtPE precursor. These studies demonstrate that even a modest reduction of mtPE in mammalian cells profoundly alters mitochondrial functions.
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Affiliation(s)
- Guergana Tasseva
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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Farine L, Bütikofer P. The ins and outs of phosphatidylethanolamine synthesis in Trypanosoma brucei. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:533-42. [PMID: 23010476 DOI: 10.1016/j.bbalip.2012.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/07/2012] [Accepted: 09/16/2012] [Indexed: 12/23/2022]
Abstract
Phospholipids are not only major building blocks of biological membranes but fulfill a wide range of critical functions that are often widely unrecognized. In this review, we focus on phosphatidylethanolamine, a major glycerophospholipid class in eukaryotes and bacteria, which is involved in many unexpected biological processes. We describe (i) the ins, i.e. the substrate sources and biochemical reactions involved in phosphatidylethanolamine synthesis, and (ii) the outs, i.e. the different roles of phosphatidylethanolamine and its involvement in various cellular events. We discuss how the protozoan parasite, Trypanosoma brucei, has contributed and may contribute in the future as eukaryotic model organism to our understanding of phosphatidylethanolamine homeostasis. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Luce Farine
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland.
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