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Watanabe Y, Iwasaki Y, Sasaki K, Motono C, Imai K, Suzuki K. Atg15 is a vacuolar phospholipase that disintegrates organelle membranes. Cell Rep 2023; 42:113567. [PMID: 38118441 DOI: 10.1016/j.celrep.2023.113567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 10/16/2023] [Accepted: 11/22/2023] [Indexed: 12/22/2023] Open
Abstract
Atg15 (autophagy-related 15) is a vacuolar phospholipase essential for the degradation of cytoplasm-to-vacuole targeting (Cvt) bodies and autophagic bodies, hereinafter referred to as intravacuolar/intralysosomal autophagic compartments (IACs), but it remains unknown if Atg15 directly disrupts IAC membranes. Here, we show that the recombinant Chaetomium thermophilum Atg15 lipase domain (CtAtg15(73-475)) possesses phospholipase activity. The activity of CtAtg15(73-475) was markedly elevated by limited digestion. We inserted the human rhinovirus 3C protease recognition sequence and found that cleavage between S159 and V160 was important to activate CtAtg15(73-475). Our molecular dynamics simulation suggested that the cleavage facilitated conformational change around the active center of CtAtg15, resulting in an exposed state. We confirmed that CtAtg15 could disintegrate S. cerevisiae IAC in vivo. Further, both mitochondria and IAC of S. cerevisiae were disintegrated by CtAtg15. This study suggests Atg15 plays a role in disrupting any organelle membranes delivered to vacuoles by autophagy.
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Affiliation(s)
- Yasunori Watanabe
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan.
| | - Yurina Iwasaki
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
| | - Kyoka Sasaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Chie Motono
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Koto-ku, Tokyo 135-0064, Japan; Computational Bio Big-Data Open Innovation Laboratory (CBBD-OIL), AIST, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Koto-ku, Tokyo 135-0064, Japan; Global Research and Development Center for Business by Quantum-AI Technology (G-QuAT), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8560, Japan
| | - Kuninori Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan; Life Science Data Research Center, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
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2
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Hrach VL, King WR, Nelson LD, Conklin S, Pollock JA, Patton-Vogt J. The acyltransferase Gpc1 is both a target and an effector of the unfolded protein response in Saccharomyces cerevisiae. J Biol Chem 2023; 299:104884. [PMID: 37269946 PMCID: PMC10331479 DOI: 10.1016/j.jbc.2023.104884] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 05/25/2023] [Accepted: 05/27/2023] [Indexed: 06/05/2023] Open
Abstract
The unfolded protein response (UPR) is sensitive to proteotoxic and membrane bilayer stress, both of which are sensed by the ER protein Ire1. When activated, Ire1 splices HAC1 mRNA, producing a transcription factor that targets genes involved in proteostasis and lipid metabolism, among others. The major membrane lipid phosphatidylcholine (PC) is subject to phospholipase-mediated deacylation, producing glycerophosphocholine (GPC), followed by reacylation of GPC through the PC deacylation/reacylation pathway (PC-DRP). The reacylation events occur via a two-step process catalyzed first by the GPC acyltransferase Gpc1, followed by acylation of the lyso-PC molecule by Ale1. However, whether Gpc1 is critical for ER bilayer homeostasis is unclear. Using an improved method for C14-choline-GPC radiolabeling, we first show that loss of Gpc1 results in abrogation of PC synthesis through PC-DRP and that Gpc1 colocalizes with the ER. We then probe the role of Gpc1 as both a target and an effector of the UPR. Exposure to the UPR-inducing compounds tunicamycin, DTT, and canavanine results in a Hac1-dependent increase in GPC1 message. Further, cells lacking Gpc1 exhibit increased sensitivity to those proteotoxic stressors. Inositol limitation, known to induce the UPR via bilayer stress, also induces GPC1 expression. Finally, we show that loss of GPC1 induces the UPR. A gpc1Δ mutant displays upregulation of the UPR in strains expressing a mutant form of Ire1 that is unresponsive to unfolded proteins, indicating that bilayer stress is responsible for the observed upregulation. Collectively, our data indicate an important role for Gpc1 in yeast ER bilayer homeostasis.
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Affiliation(s)
- Victoria Lee Hrach
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - William R King
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Laura D Nelson
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Shane Conklin
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - John A Pollock
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.
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3
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Yu L, Zhou C, Fan J, Shanklin J, Xu C. Mechanisms and functions of membrane lipid remodeling in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:37-53. [PMID: 33853198 DOI: 10.1111/tpj.15273] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 05/20/2023]
Abstract
Lipid remodeling, defined herein as post-synthetic structural modifications of membrane lipids, play crucial roles in regulating the physicochemical properties of cellular membranes and hence their many functions. Processes affected by lipid remodeling include lipid metabolism, membrane repair, cellular homeostasis, fatty acid trafficking, cellular signaling and stress tolerance. Glycerolipids are the major structural components of cellular membranes and their composition can be adjusted by modifying their head groups, their acyl chain lengths and the number and position of double bonds. This review summarizes recent advances in our understanding of mechanisms of membrane lipid remodeling with emphasis on the lipases and acyltransferases involved in the modification of phosphatidylcholine and monogalactosyldiacylglycerol, the major membrane lipids of extraplastidic and photosynthetic membranes, respectively. We also discuss the role of triacylglycerol metabolism in membrane acyl chain remodeling. Finally, we discuss emerging data concerning the functional roles of glycerolipid remodeling in plant stress responses. Illustrating the molecular basis of lipid remodeling may lead to novel strategies for crop improvement and other biotechnological applications such as bioenergy production.
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Affiliation(s)
- Linhui Yu
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Chao Zhou
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
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4
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FSH1 encodes lysophospholipase activity in Saccharomyces cerevisiae. Biotechnol Lett 2020; 43:279-286. [PMID: 32920715 DOI: 10.1007/s10529-020-03004-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/08/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVES To elucidate the role of FSH1 (family of serine hydrolase) in lipid homeostasis. RESULTS Proteins in various species containing alpha/beta hydrolase domain are known to be involved in lipid metabolism. In silico analysis of the FSH1 gene in Saccharomyces cerevisiae revealed the presence of alpha/beta hydrolase domain (ABHD) and a lipase motif (GXSXG), however its function in lipid metabolism remained elusive. The overexpression of FSH1 in WT and fsh1Δ cells showed a significant reduction in the cellular phospholipid levels and an increase in the triacylglycerol levels and lipid droplet (LD) number. Furthermore, the purified recombinant protein Fsh1p was identified as a lysophospholipase that specifically acts on lysophosphatidylserine (LPS) and impacts the lipid homeostasis in S. cerevisiae. CONCLUSIONS These results depicted that Fsh1p has a role on lipid homeostasis and is a lysophospholipase that hydrolyzes lysophosphatidylserine (LPS).
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5
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Patton-Vogt J, de Kroon AIPM. Phospholipid turnover and acyl chain remodeling in the yeast ER. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158462. [PMID: 31146038 PMCID: PMC10716787 DOI: 10.1016/j.bbalip.2019.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/01/2019] [Accepted: 05/15/2019] [Indexed: 12/14/2022]
Abstract
The turnover of phospholipids plays an essential role in membrane lipid homeostasis by impacting both lipid head group and acyl chain composition. This review focusses on the degradation and acyl chain remodeling of the major phospholipid classes present in the ER membrane of the reference eukaryote Saccharomyces cerevisiae, i.e. phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE). Phospholipid turnover reactions are introduced, and the occurrence and important functions of phospholipid remodeling in higher eukaryotes are briefly summarized. After presenting an inventory of established mechanisms of phospholipid acyl chain exchange, current knowledge of phospholipid degradation and remodeling by phospholipases and acyltransferases localized to the yeast ER is summarized. PC is subject to the PC deacylation-reacylation remodeling pathway (PC-DRP) involving a phospholipase B, the recently identified glycerophosphocholine acyltransferase Gpc1p, and the broad specificity acyltransferase Ale1p. PI is post-synthetically enriched in C18:0 acyl chains by remodeling reactions involving Cst26p. PE may undergo turnover by the phospholipid: diacylglycerol acyltransferase Lro1p as first step in acyl chain remodeling. Clues as to the functions of phospholipid acyl chain remodeling are discussed.
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Affiliation(s)
- Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA, USA
| | - Anton I P M de Kroon
- Membrane Biochemistry & Biophysics, Bijvoet Center and Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands.
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6
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Anaokar S, Kodali R, Jonik B, Renne MF, Brouwers JFHM, Lager I, de Kroon AIPM, Patton-Vogt J. The glycerophosphocholine acyltransferase Gpc1 is part of a phosphatidylcholine (PC)-remodeling pathway that alters PC species in yeast. J Biol Chem 2018; 294:1189-1201. [PMID: 30514764 DOI: 10.1074/jbc.ra118.005232] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/27/2018] [Indexed: 12/22/2022] Open
Abstract
Phospholipase B-mediated hydrolysis of phosphatidylcholine (PC) results in the formation of free fatty acids and glycerophosphocholine (GPC) in the yeast Saccharomyces cerevisiae GPC can be reacylated by the glycerophosphocholine acyltransferase Gpc1, which produces lysophosphatidylcholine (LPC), and LPC can be converted to PC by the lysophospholipid acyltransferase Ale1. Here, we further characterized the regulation and function of this distinct PC deacylation/reacylation pathway in yeast. Through in vitro and in vivo experiments, we show that Gpc1 and Ale1 are the major cellular GPC and LPC acyltransferases, respectively. Importantly, we report that Gpc1 activity affects the PC species profile. Loss of Gpc1 decreased the levels of monounsaturated PC species and increased those of diunsaturated PC species, whereas Gpc1 overexpression had the opposite effects. Of note, Gpc1 loss did not significantly affect phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine profiles. Our results indicate that Gpc1 is involved in postsynthetic PC remodeling that produces more saturated PC species. qRT-PCR analyses revealed that GPC1 mRNA abundance is regulated coordinately with PC biosynthetic pathways. Inositol availability, which regulates several phospholipid biosynthetic genes, down-regulated GPC1 expression at the mRNA and protein levels and, as expected, decreased levels of monounsaturated PC species. Finally, loss of GPC1 decreased stationary phase viability in inositol-free medium. These results indicate that Gpc1 is part of a postsynthetic PC deacylation/reacylation remodeling pathway (PC-DRP) that alters the PC species profile, is regulated in coordination with other major lipid biosynthetic pathways, and affects yeast growth.
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Affiliation(s)
- Sanket Anaokar
- Departments of Biological Sciences, Pittsburgh, Pennsylvania 15282
| | - Ravindra Kodali
- Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Benjamin Jonik
- Departments of Biological Sciences, Pittsburgh, Pennsylvania 15282
| | - Mike F Renne
- Department of Membrane Biochemistry & Biophysics, Bijvoet Center and Institute of Biomembranes, 3584 CH Utrecht, The Netherlands
| | - Jos F H M Brouwers
- Department of Biochemistry and Cell Biology, Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
| | - Anton I P M de Kroon
- Department of Membrane Biochemistry & Biophysics, Bijvoet Center and Institute of Biomembranes, 3584 CH Utrecht, The Netherlands
| | - Jana Patton-Vogt
- Departments of Biological Sciences, Pittsburgh, Pennsylvania 15282.
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7
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Binek A, Rojo D, Godzien J, Rupérez FJ, Nuñez V, Jorge I, Ricote M, Vázquez J, Barbas C. Flow Cytometry Has a Significant Impact on the Cellular Metabolome. J Proteome Res 2018; 18:169-181. [PMID: 30362351 DOI: 10.1021/acs.jproteome.8b00472] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The characterization of specialized cell subpopulations in a heterogeneous tissue is essential for understanding organ function in health and disease. A popular method of cell isolation is fluorescence-activated cell sorting (FACS) based on probes that bind surface or intracellular markers. In this study, we analyze the impact of FACS on the cell metabolome of mouse peritoneal macrophages. Compared with directly pelleted macrophages, FACS-treated cells had an altered content of metabolites related to the plasma membrane, activating a mechanosensory signaling cascade causing inflammation-like stress. The procedure also triggered alterations related to energy consumption and cell damage. The observed changes mostly derive from the physical impact on cells during their passage through the instrument. These findings provide evidence of FACS-induced biochemical changes, which should be taken into account in the design of robust metabolic assays of cells separated by flow cytometry.
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Affiliation(s)
- Aleksandra Binek
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid 28029 , Spain 1
| | - David Rojo
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia , Universidad CEU San Pablo , Campus Montepríncipe , Madrid 28668 , Spain
| | - Joanna Godzien
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia , Universidad CEU San Pablo , Campus Montepríncipe , Madrid 28668 , Spain
| | - Francisco Javier Rupérez
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia , Universidad CEU San Pablo , Campus Montepríncipe , Madrid 28668 , Spain
| | - Vanessa Nuñez
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid 28029 , Spain 1
| | - Inmaculada Jorge
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid 28029 , Spain 1.,CIBER de Enfermedades Cardiovasculares (CIBER CV), Madrid 28029 , Spain
| | - Mercedes Ricote
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid 28029 , Spain 1
| | - Jesús Vázquez
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid 28029 , Spain 1.,CIBER de Enfermedades Cardiovasculares (CIBER CV), Madrid 28029 , Spain
| | - Coral Barbas
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia , Universidad CEU San Pablo , Campus Montepríncipe , Madrid 28668 , Spain
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8
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Nitrogen-starvation triggers cellular accumulation of triacylglycerol in Metarhizium robertsii. Fungal Biol 2018; 122:410-419. [DOI: 10.1016/j.funbio.2017.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/13/2017] [Accepted: 07/06/2017] [Indexed: 01/11/2023]
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9
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Phospholipases play multiple cellular roles including growth, stress tolerance, sexual development, and virulence in fungi. Microbiol Res 2018; 209:55-69. [DOI: 10.1016/j.micres.2017.12.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 12/21/2017] [Accepted: 12/31/2017] [Indexed: 12/16/2022]
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10
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Liu Y, Li M, Huang L, Gui S, Jia L, Zheng D, Fu Y, Zhang Y, Rui J, Lu F. Cloning, expression and characterisation of phospholipase B from Saccharomyces cerevisiae and its application in the synthesis of l-alpha-glycerylphosphorylcholine and peanut oil degumming. BIOTECHNOL BIOTEC EQ 2018. [DOI: 10.1080/13102818.2018.1455536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Yihan Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin, PR China
- National Engineering Laboratory for Industrial Enzymes, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Mingjie Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Lin Huang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin, PR China
- Tianjin Key Laboratory of Industrial Microbiology, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Shuang Gui
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Leibo Jia
- Tianjin Key Laboratory of Industrial Microbiology, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Dong Zheng
- Tianjin Key Laboratory of Industrial Microbiology, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Yu Fu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Yutong Zhang
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Jinqiu Rui
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
| | - Fuping Lu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin, PR China
- National Engineering Laboratory for Industrial Enzymes, Tianjin, PR China
- The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China
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11
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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: 21] [Impact Index Per Article: 3.5] [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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12
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The Role of Lipid Droplets in Mortierella alpina Aging Revealed by Integrative Subcellular and Whole-Cell Proteome Analysis. Sci Rep 2017; 7:43896. [PMID: 28266581 PMCID: PMC5339828 DOI: 10.1038/srep43896] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/25/2017] [Indexed: 01/10/2023] Open
Abstract
Lipid droplets (LDs) participate in many cellular processes in oleaginous microorganisms. However, the exact function of LDs in the Mortierella alpina aging process remains elusive. Herein, subcellular proteomics was employed to unveil the composition and dynamics of the LD proteome in the aging M. alpina for the first time. More than 400 proteins were detected in LDs and 62 of them changed expression significantly during aging. By combining the LD proteomic data with whole-cell data, we found that the carbohydrate metabolism and de novo lipid biosynthesis were all inhibited during aging of M. alpina mycelia. The up-regulation of fructose metabolism-related enzymes in LDs might imply that LDs facilitated the fructose metabolism, which in turn might cause pyruvate to accumulate and enter malate-pyruvate cycle, and ultimately, provide additional NADPH for the synthesis of arachidonic acid (ARA). Lysophospholipase and lecithinase were up-regulated in LDs during the aging process, suggesting that the phospholipids and lecithin were starting to be hydrolyzed, in order to release fatty acids for the cells. The impairment of the anti-oxidant system might lead to the accumulation of ROS and consequently cause the up-regulation of autophagy-related proteins in LDs, which further induces the M. alpina mycelia to activate the autophagy process.
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13
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Ramya V, Rajasekharan R. ATG15
encodes a phospholipase and is transcriptionally regulated by YAP1 in Saccharomyces cerevisiae. FEBS Lett 2016; 590:3155-67. [DOI: 10.1002/1873-3468.12369] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 01/23/2023]
Affiliation(s)
- Visvanathan Ramya
- Lipidomics Centre; Department of Lipid Science; Central Food Technological Research Institute; Council of Scientific and Industrial Research; Mysore Karnataka India
- Academy of Scientific and Innovative Research; Mysore Karnataka India
| | - Ram Rajasekharan
- Lipidomics Centre; Department of Lipid Science; Central Food Technological Research Institute; Council of Scientific and Industrial Research; Mysore Karnataka India
- Academy of Scientific and Innovative Research; Mysore Karnataka India
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14
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Renne MF, Bao X, De Smet CH, de Kroon AIPM. Lipid Acyl Chain Remodeling in Yeast. Lipid Insights 2016; 8:33-40. [PMID: 26819558 PMCID: PMC4720183 DOI: 10.4137/lpi.s31780] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/21/2015] [Indexed: 11/05/2022] Open
Abstract
Membrane lipid homeostasis is maintained by de novo synthesis, intracellular transport, remodeling, and degradation of lipid molecules. Glycerophospholipids, the most abundant structural component of eukaryotic membranes, are subject to acyl chain remodeling, which is defined as the post-synthetic process in which one or both acyl chains are exchanged. Here, we review studies addressing acyl chain remodeling of membrane glycerophospholipids in Saccharomyces cerevisiae, a model organism that has been successfully used to investigate lipid synthesis and its regulation. Experimental evidence for the occurrence of phospholipid acyl chain exchange in cardiolipin, phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine is summarized, including methods and tools that have been used for detecting remodeling. Progress in the identification of the enzymes involved is reported, and putative functions of acyl chain remodeling in yeast are discussed.
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Affiliation(s)
- Mike F Renne
- Membrane Biochemistry and Biophysics, Bijvoet Center for Biomolecular Research, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Xue Bao
- Membrane Biochemistry and Biophysics, Bijvoet Center for Biomolecular Research, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Cedric H De Smet
- Membrane Biochemistry and Biophysics, Bijvoet Center for Biomolecular Research, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands.; Present address: Division of Cell Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Anton I P M de Kroon
- Membrane Biochemistry and Biophysics, Bijvoet Center for Biomolecular Research, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
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15
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Surlow BA, Cooley BM, Needham PG, Brodsky JL, Patton-Vogt J. Loss of Ypk1, the yeast homolog to the human serum- and glucocorticoid-induced protein kinase, accelerates phospholipase B1-mediated phosphatidylcholine deacylation. J Biol Chem 2014; 289:31591-604. [PMID: 25258318 DOI: 10.1074/jbc.m114.581157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Ypk1, the yeast homolog of the human serum- and glucocorticoid-induced kinase (Sgk1), affects diverse cellular activities, including sphingolipid homeostasis. We now report that Ypk1 also impacts the turnover of the major phospholipid, phosphatidylcholine (PC). Pulse-chase radiolabeling reveals that a ypk1Δ mutant exhibits increased PC deacylation and glycerophosphocholine production compared with wild type yeast. Deletion of PLB1, a gene encoding a B-type phospholipase that hydrolyzes PC, in a ypk1Δ mutant curtails the increased PC deacylation. In contrast to previous data, we find that Plb1 resides in the ER and in the medium. Consistent with a link between Ypk1 and Plb1, the levels of both Plb1 protein and PLB1 message are elevated in a ypk1Δ strain compared with wild type yeast. Furthermore, deletion of PLB1 in a ypk1Δ mutant exacerbates phenotypes associated with loss of YPK1, including slowed growth and sensitivity to cell wall perturbation, suggesting that increased Plb1 activity buffers against the loss of Ypk1. Because Plb1 lacks a consensus phosphorylation site for Ypk1, we probed other processes under the control of Ypk1 that might be linked to PC turnover. Inhibition of sphingolipid biosynthesis by the drug myriocin or through utilization of a lcb1-100 mutant results in increased PLB1 expression. Furthermore, we discovered that the increase in PLB1 expression observed upon inhibition of sphingolipid synthesis or loss of Ypk1 is under the control of the Crz1 transcription factor. Taken together, these results suggest a functional interaction between Ypk1 and Plb1 in which altered sphingolipid metabolism up-regulates PLB1 expression via Crz1.
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Affiliation(s)
- Beth A Surlow
- From the Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania 15282 and
| | - Benjamin M Cooley
- From the Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania 15282 and
| | - Patrick G Needham
- the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Jeffrey L Brodsky
- the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Jana Patton-Vogt
- From the Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania 15282 and
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16
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Selvaraju K, Rajakumar S, Nachiappan V. Identification of a phospholipase B encoded by the LPL1 gene in Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1842:1383-92. [PMID: 25014274 DOI: 10.1016/j.bbalip.2014.06.013] [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] [Received: 01/27/2014] [Revised: 06/26/2014] [Accepted: 06/28/2014] [Indexed: 10/25/2022]
Abstract
Phospholipids also play a major role in maintaining the lipid droplet (LD) morphology. In our current study, deletion of LPL1 resulted in altered morphology of LDs and was confirmed by microscopic analysis. LPL1/YOR059c contains lipase specific motif GXSXG and acetate labeling in the LPL1 overexpressed strains depicted a decrease in glycerophospholipids and an increase in free fatty acids. The purified Lpl1p showed phospholipase activity with broader substrate specificity, acting on all glycerophospholipids primarily at sn-2 position and later at sn-1 position. Localization studies precisely revealed that Lpl1 is exclusively localized in the LD at the stationary phase. Site directed mutagenesis experiments clearly demonstrated that the lipase motif is vital for the phospholipase activity. In summary, our results demonstrate that yeast Lpl1 exerts phospholipase activity, plays a vital role in LD morphology, and its absence results in altered LD size. Based on the localization and enzyme activity we renamed YOR059c as LPL1 (LD phospholipase 1).
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Affiliation(s)
- Kandasamy Selvaraju
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620024, Tamilnadu, India
| | - Selvaraj Rajakumar
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620024, Tamilnadu, India
| | - Vasanthi Nachiappan
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620024, Tamilnadu, India.
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17
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Fujino S, Akiyama D, Akaboshi S, Fujita T, Watanabe Y, Tamai Y. Purification and Characterization of Phospholipase B fromCandida utilis. Biosci Biotechnol Biochem 2014; 70:377-86. [PMID: 16495653 DOI: 10.1271/bbb.70.377] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Phospholipase B (PLB) from the asporogenous yeast Candida utilis was purified to homogeneity from a culture broth. The apparent molecular mass was 90-110 kDa by SDS-PAGE. The enzyme had two pH optima, one acidic (pH 3.0) and the other alkaline (pH 7.5). At acidic pH the enzyme hydrolyzed all phospholipids tested without metal ions. On the other hand, the PLB showed substrate specificity and required metal ions for alkaline activity. The cDNA sequence of the PLB was analyzed by a combination of several PCR procedures. The PLB encoded a protein consisting of 643 amino acids. The amino acid sequence contained a lipase consensus sequence (GxSxG) and catalytic arginine and aspartic acid motifs which were identified as the catalytic triad in the PLB from Kluyveromyces lactis, suggesting that the catalytic mechanism of the PLB is similar to that of cytosolic phospholipase A(2) (cPLA(2)), found in mammalian tissues.
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Affiliation(s)
- Shuji Fujino
- Laboratory of Food Biochemistry, Department of Bioresources, Faculty of Agriculture, Ehime University, Japan
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18
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Klug L, Daum G. Yeast lipid metabolism at a glance. FEMS Yeast Res 2014; 14:369-88. [DOI: 10.1111/1567-1364.12141] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/23/2014] [Accepted: 02/02/2014] [Indexed: 01/07/2023] Open
Affiliation(s)
- Lisa Klug
- Institute of Biochemistry; Graz University of Technology; Graz Austria
| | - Günther Daum
- Institute of Biochemistry; Graz University of Technology; Graz Austria
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19
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Fernández-Murray JP, Ngo MH, McMaster CR. Choline transport activity regulates phosphatidylcholine synthesis through choline transporter Hnm1 stability. J Biol Chem 2013; 288:36106-15. [PMID: 24187140 DOI: 10.1074/jbc.m113.499855] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Choline is a precursor for the synthesis of phosphatidylcholine through the CDP-choline pathway. Saccharomyces cerevisiae expresses a single high affinity choline transporter at the plasma membrane, encoded by the HNM1 gene. We show that exposing cells to increasing levels of choline results in two different regulatory mechanisms impacting Hnm1 activity. Initial exposure to choline results in a rapid decrease in Hnm1-mediated transport at the level of transporter activity, whereas chronic exposure results in Hnm1 degradation through an endocytic mechanism that depends on the ubiquitin ligase Rsp5 and the casein kinase 1 redundant pair Yck1/Yck2. We present details of how the choline transporter is a major regulator of phosphatidylcholine synthesis.
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Affiliation(s)
- J Pedro Fernández-Murray
- From the Department of Pharmacology, Atlantic Research Centre, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
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20
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Matsumoto Y, Mineta S, Murayama K, Sugimori D. A novel phospholipase B fromStreptomycessp. NA684 - purification, characterization, gene cloning, extracellular production and prediction of the catalytic residues. FEBS J 2013; 280:3780-96. [DOI: 10.1111/febs.12366] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/24/2013] [Accepted: 05/21/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Yusaku Matsumoto
- Department of Symbiotic Systems Science and Technology; Graduate School of Symbiotic Systems Science and Technology; Fukushima University; Japan
| | - Shingo Mineta
- Department of Symbiotic Systems Science and Technology; Graduate School of Symbiotic Systems Science and Technology; Fukushima University; Japan
| | - Kazutaka Murayama
- Division of Biomedical Measurements and Diagnostics; Graduate School of Biomedical Engineering; Tohoku University; Sendai Japan
| | - Daisuke Sugimori
- Department of Symbiotic Systems Science and Technology; Graduate School of Symbiotic Systems Science and Technology; Fukushima University; Japan
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21
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Dedieu L, Serveau-Avesque C, Canaan S. Identification of residues involved in substrate specificity and cytotoxicity of two closely related cutinases from Mycobacterium tuberculosis. PLoS One 2013; 8:e66913. [PMID: 23843969 PMCID: PMC3699616 DOI: 10.1371/journal.pone.0066913] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/11/2013] [Indexed: 11/20/2022] Open
Abstract
The enzymes belonging to the cutinase family are serine enzymes active on a large panel of substrates such as cutin, triacylglycerols, and phospholipids. In the M. tuberculosis H37Rv genome, seven genes coding for cutinase-like proteins have been identified with strong immunogenic properties suggesting a potential role as vaccine candidates. Two of these enzymes which are secreted and highly homologous, possess distinct substrates specificities. Cfp21 is a lipase and Cut4 is a phospholipase A2, which has cytotoxic effects on macrophages. Structural overlay of their three-dimensional models allowed us to identify three areas involved in the substrate binding process and to shed light on this substrate specificity. By site-directed mutagenesis, residues present in these Cfp21 areas were replaced by residues occurring in Cut4 at the same location. Three mutants acquired phospholipase A1 and A2 activities and the lipase activities of two mutants were 3 and 15 fold greater than the Cfp21 wild type enzyme. In addition, contrary to mutants with enhanced lipase activity, mutants that acquired phospholipase B activities induced macrophage lysis as efficiently as Cut4 which emphasizes the relationship between apparent phospholipase A2 activity and cytotoxicity. Modification of areas involved in substrate specificity, generate recombinant enzymes with higher activity, which may be more immunogenic than the wild type enzymes and could therefore constitute promising candidates for antituberculous vaccine production.
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Affiliation(s)
- Luc Dedieu
- CNRS - Aix-Marseille Université - Enzymologie Interfaciale et Physiologie de la Lipolyse - UMR 7282, Marseille, France
| | - Carole Serveau-Avesque
- CNRS - Aix-Marseille Université - Enzymologie Interfaciale et Physiologie de la Lipolyse - UMR 7282, Marseille, France
| | - Stéphane Canaan
- CNRS - Aix-Marseille Université - Enzymologie Interfaciale et Physiologie de la Lipolyse - UMR 7282, Marseille, France
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22
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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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23
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De Smet CH, Cox R, Brouwers JF, de Kroon AIPM. Yeast cells accumulate excess endogenous palmitate in phosphatidylcholine by acyl chain remodeling involving the phospholipase B Plb1p. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1167-76. [PMID: 23501167 DOI: 10.1016/j.bbalip.2013.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 11/18/2022]
Abstract
In the yeast Saccharomyces cerevisiae, the molecular species profile of the major membrane glycerophospholipid phosphatidylcholine (PC) is determined by the molecular species-selectivity of the biosynthesis routes and by acyl chain remodeling. Overexpression of the glycerol-3-phosphate acyltransferase Sct1p was recently shown to induce a strong increase in the cellular content of palmitate (C16:0). Using stable isotope labeling and mass spectrometry, the present study shows that wild type yeast overexpressing Sct1p incorporates excess C16:0 into PC via the methylation of PE, the CDP-choline route, and post-synthetic acyl chain remodeling. Overexpression of Sct1p increased the extent of remodeling of PE-derived PC, providing a novel tool to perform mechanistic studies on PC acyl chain exchange. The exchange of acyl chains occurred at both the sn-1 and sn-2 positions of the glycerol backbone of PC, and required the phospholipase B Plb1p for optimal efficiency. Sct1p-catalyzed acyl chain exchange, the acyl-CoA binding protein Acb1p, the Plb1p homologue Plb2p, and the glycerophospholipid:triacylglycerol transacylase Lro1p were not required for PC remodeling. The results indicate that PC serves as a buffer for excess cellular C16:0.
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24
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Michaillat L, Mayer A. Identification of genes affecting vacuole membrane fragmentation in Saccharomyces cerevisiae. PLoS One 2013; 8:e54160. [PMID: 23383298 PMCID: PMC3562189 DOI: 10.1371/journal.pone.0054160] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/10/2012] [Indexed: 11/19/2022] Open
Abstract
The equilibrium of membrane fusion and fission influences the volume and copy number of organelles. Fusion of yeast vacuoles has been well characterized but their fission and the mechanisms determining vacuole size and abundance remain poorly understood. We therefore attempted to systematically characterize factors necessary for vacuole fission. Here, we present results of an in vivo screening for deficiencies in vacuolar fragmentation activity of an ordered collection deletion mutants, representing 4881 non-essential genes of the yeast Saccharomyces cerevisiae. The screen identified 133 mutants with strong defects in vacuole fragmentation. These comprise numerous known fragmentation factors, such as the Fab1p complex, Tor1p, Sit4p and the V-ATPase, thus validating the approach. The screen identified many novel factors promoting vacuole fragmentation. Among those are 22 open reading frames of unknown function and three conspicuous clusters of proteins with known function. The clusters concern the ESCRT machinery, adaptins, and lipases, which influence the production of diacylglycerol and phosphatidic acid. A common feature of these factors of known function is their capacity to change membrane curvature, suggesting that they might promote vacuole fragmentation via this property.
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Affiliation(s)
- Lydie Michaillat
- Département de Biochimie, Université de Lausanne, Epalinges, Switzerland
| | - Andreas Mayer
- Département de Biochimie, Université de Lausanne, Epalinges, Switzerland
- * E-mail:
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25
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Mora G, Scharnewski M, Fulda M. Neutral lipid metabolism influences phospholipid synthesis and deacylation in Saccharomyces cerevisiae. PLoS One 2012; 7:e49269. [PMID: 23139841 PMCID: PMC3489728 DOI: 10.1371/journal.pone.0049269] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 10/07/2012] [Indexed: 12/29/2022] Open
Abstract
Establishment and maintenance of equilibrium in the fatty acid (FA) composition of phospholipids (PL) requires both regulation of the substrate available for PL synthesis (the acyl-CoA pool) and extensive PL turnover and acyl editing. In the present study, we utilize acyl-CoA synthetase (ACS) deficient cells, unable to recycle FA derived from lipid deacylation, to evaluate the role of several enzymatic activities in FA trafficking and PL homeostasis in Saccharomyces cerevisiae. The data presented show that phospholipases B are not contributing to constitutive PL deacylation and are therefore unlikely to be involved in PL remodeling. In contrast, the enzymes of neutral lipid (NL) synthesis and mobilization are central mediators of FA trafficking. The phospholipid:DAG acyltransferase (PDAT) Lro1p has a substantial effect on FA release and on PL equilibrium, emerging as an important mediator in PL remodeling. The acyl-CoA dependent biosynthetic activities of NL metabolism are also involved in PL homeostasis through active modulation of the substrate available for PL synthesis. In addition TAG mobilization makes an important contribution, especially in cells from stationary phase, to FA availability. Beyond its well-established role in the formation of a storage pool, NL metabolism could play a crucial role as a mechanism to uncouple the pools of PL and acyl-CoAs from each other and thereby to allow independent regulation of each one.
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Affiliation(s)
- Gabriel Mora
- Department of Plant Biochemistry, Albrecht-von-Haller Institute, Georg-August University Goettingen, Goettingen, Germany
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26
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Abstract
Due to its genetic tractability and increasing wealth of accessible data, the yeast Saccharomyces cerevisiae is a model system of choice for the study of the genetics, biochemistry, and cell biology of eukaryotic lipid metabolism. Glycerolipids (e.g., phospholipids and triacylglycerol) and their precursors are synthesized and metabolized by enzymes associated with the cytosol and membranous organelles, including endoplasmic reticulum, mitochondria, and lipid droplets. Genetic and biochemical analyses have revealed that glycerolipids play important roles in cell signaling, membrane trafficking, and anchoring of membrane proteins in addition to membrane structure. The expression of glycerolipid enzymes is controlled by a variety of conditions including growth stage and nutrient availability. Much of this regulation occurs at the transcriptional level and involves the Ino2–Ino4 activation complex and the Opi1 repressor, which interacts with Ino2 to attenuate transcriptional activation of UASINO-containing glycerolipid biosynthetic genes. Cellular levels of phosphatidic acid, precursor to all membrane phospholipids and the storage lipid triacylglycerol, regulates transcription of UASINO-containing genes by tethering Opi1 to the nuclear/endoplasmic reticulum membrane and controlling its translocation into the nucleus, a mechanism largely controlled by inositol availability. The transcriptional activator Zap1 controls the expression of some phospholipid synthesis genes in response to zinc availability. Regulatory mechanisms also include control of catalytic activity of glycerolipid enzymes by water-soluble precursors, products and lipids, and covalent modification of phosphorylation, while in vivo function of some enzymes is governed by their subcellular location. Genome-wide genetic analysis indicates coordinate regulation between glycerolipid metabolism and a broad spectrum of metabolic pathways.
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27
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Sun T, Wetzel SJ, Johnson ME, Surlow BA, Patton-Vogt J. Development and validation of a hydrophilic interaction liquid chromatography–tandem mass spectrometry method for the quantification of lipid-related extracellular metabolites in Saccharomyces cerevisiae. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 897:1-9. [DOI: 10.1016/j.jchromb.2012.03.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 03/16/2012] [Accepted: 03/25/2012] [Indexed: 01/24/2023]
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28
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Ponnapalli SP, Saunders MA, Van Loan CF, Alter O. A higher-order generalized singular value decomposition for comparison of global mRNA expression from multiple organisms. PLoS One 2011; 6:e28072. [PMID: 22216090 PMCID: PMC3245232 DOI: 10.1371/journal.pone.0028072] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 10/31/2011] [Indexed: 11/18/2022] Open
Abstract
The number of high-dimensional datasets recording multiple aspects of a single phenomenon is increasing in many areas of science, accompanied by a need for mathematical frameworks that can compare multiple large-scale matrices with different row dimensions. The only such framework to date, the generalized singular value decomposition (GSVD), is limited to two matrices. We mathematically define a higher-order GSVD (HO GSVD) for N≥2 matrices , each with full column rank. Each matrix is exactly factored as Di = UiΣiVT, where V, identical in all factorizations, is obtained from the eigensystem SV = VΛ of the arithmetic mean S of all pairwise quotients of the matrices , i≠j. We prove that this decomposition extends to higher orders almost all of the mathematical properties of the GSVD. The matrix S is nondefective with V and Λ real. Its eigenvalues satisfy λk≥1. Equality holds if and only if the corresponding eigenvector vk is a right basis vector of equal significance in all matrices Di and Dj, that is σi,k/σj,k = 1 for all i and j, and the corresponding left basis vector ui,k is orthogonal to all other vectors in Ui for all i. The eigenvalues λk = 1, therefore, define the “common HO GSVD subspace.” We illustrate the HO GSVD with a comparison of genome-scale cell-cycle mRNA expression from S. pombe, S. cerevisiae and human. Unlike existing algorithms, a mapping among the genes of these disparate organisms is not required. We find that the approximately common HO GSVD subspace represents the cell-cycle mRNA expression oscillations, which are similar among the datasets. Simultaneous reconstruction in the common subspace, therefore, removes the experimental artifacts, which are dissimilar, from the datasets. In the simultaneous sequence-independent classification of the genes of the three organisms in this common subspace, genes of highly conserved sequences but significantly different cell-cycle peak times are correctly classified.
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Affiliation(s)
- Sri Priya Ponnapalli
- Department of Electrical and Computer Engineering, University of Texas at Austin, Texas, United States of America
| | - Michael A. Saunders
- Department of Management Science and Engineering, Stanford University, Stanford, California, United States of America
| | - Charles F. Van Loan
- Department of Computer Science, Cornell University, Ithaca, New York, United States of America
| | - Orly Alter
- Scientific Computing and Imaging (SCI) Institute and Departments of Bioengineering and Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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29
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Dennis EA, Cao J, Hsu YH, Magrioti V, Kokotos G. Phospholipase A2 enzymes: physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention. Chem Rev 2011; 111:6130-85. [PMID: 21910409 PMCID: PMC3196595 DOI: 10.1021/cr200085w] [Citation(s) in RCA: 794] [Impact Index Per Article: 61.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward A. Dennis
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Jian Cao
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Yuan-Hao Hsu
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
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30
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Abstract
Phospholipase A(1) (PLA(1)) is an enzyme that hydrolyzes phospholipids and produces 2-acyl-lysophospholipids and fatty acids. This lipolytic activity is conserved in a wide range of organisms but is carried out by a diverse set of PLA(1) enzymes. Where their function is known, PLA(1)s have been shown to act as digestive enzymes, possess central roles in membrane maintenance and remodeling, or regulate important cellular mechanisms by the production of various lysophospholipid mediators, such as lysophosphatidylserine and lysophosphatidic acid, which in turn have multiple biological functions.
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Affiliation(s)
- Gregory S. Richmond
- Agilent Technologies, Molecular Separations, Santa Clara, CA 95051, USA; E-Mail:
| | - Terry K. Smith
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, UK
- To whom correspondence should be addressed; E-Mail: ; Tel.: +44-1334-463412; Fax: +44-1334-462595
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31
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Rajakumari S, Daum G. Multiple functions as lipase, steryl ester hydrolase, phospholipase, and acyltransferase of Tgl4p from the yeast Saccharomyces cerevisiae. J Biol Chem 2010; 285:15769-76. [PMID: 20332534 DOI: 10.1074/jbc.m109.076331] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Triacylglycerol (TAG) hydrolysis, membrane lipid biosynthesis, and lipid turnover are largely interlinked processes. In yeast, TAG is mobilized by three TAG lipases named Tgl3p, Tgl4p, and Tgl5p, which are localized to lipid particles/droplets. These TAG lipases posses a conserved GXSXG motif that is characteristic of hydrolytic enzymes. Here, we demonstrated that the yeast TAG lipase Tgl4p, the functional ortholog of the adipose TAG lipase, ATGL, catalyzes multiple functions in lipid metabolism. An extended domain and motif search analysis revealed that Tgl4p bears not only a lipase consensus domain but also a conserved motif for calcium-independent phospholipase A(2). We show that Tgl4p exhibits TAG lipase, steryl ester hydrolase, and phospholipase A(2) activities, but surprisingly it also catalyzed the acyl-CoA-dependent acylation of lysophosphatidic acid to phosphatidic acid (PA). Heterologous overexpression of Tgl4p in Pichia pastoris increased total phospholipid and specifically PA synthesis. Moreover, deletion of TGL4 in Saccharomyces cerevisiae showed an altered pattern of phosphatidylcholine and PA molecular species. Altogether, our data suggest that yeast Tgl4p functions as a hydrolytic enzyme in lipid degradation but also contributes to fatty acid channeling and phospholipid remodeling.
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Affiliation(s)
- Sona Rajakumari
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
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32
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Deng L, Fukuda R, Kakihara T, Narita K, Ohta A. Incorporation and remodeling of phosphatidylethanolamine containing short acyl residues in yeast. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:635-45. [PMID: 20176132 DOI: 10.1016/j.bbalip.2010.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 01/06/2010] [Accepted: 02/11/2010] [Indexed: 11/17/2022]
Abstract
Phosphatidylethanolamine (PE) is one of the essential phospholipids in the yeast Saccharomyces cerevisiae. We have previously shown that a yeast strain, the endogenous PE synthesis of which was controllable, grew in the presence of PE containing decanoyl residues (diC10PE) when PE synthesis was repressed. In this study, we investigated the fate of diC10PE, its uptake and remodeling in yeast. Deletion of the genes encoding Lem3p/Ros3p or P-type ATPases, Dnf1p and Dnf2p, impaired the growth of the mutants in the medium containing diC10PE, suggesting the involvement of these proteins in the uptake of diC10PE. Analysis of the metabolism of deuterium-labeled diC10PE by electrospray ionization tandem mass spectrometry revealed that it was rapidly converted to deuterium-labeled PEs containing C16 or C18 acyl residues. The probable intermediate PEs that contained decanoic acid and C16 or C18 fatty acids as acyl residues were also detected. In addition, a substantial amount of decanoic acid was released into the culture medium during growth in the presence of diC10PE. These results imply that diC10PE was remodeled to PEs with longer acyl residues and used as membrane components. Defects in the remodeling of diC10PE in the deletion mutants of ALE1 and SLC1, products of which were capable of acyl-transfer to the sn-2 position of lyso-phospholipids, suggested their involvement in the introduction of acyl residues to the sn-2 position of lyso-phosphatidylethanolamine in the remodeling reaction of diC10PE. Our results also suggest the presence of a mechanism to maintain the physiological length of PE acyl residues in yeast.
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Affiliation(s)
- Lan Deng
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Neurofibromin homologs Ira1 and Ira2 affect glycerophosphoinositol production and transport in Saccharomyces cerevisiae. EUKARYOTIC CELL 2009; 8:1808-11. [PMID: 19717739 DOI: 10.1128/ec.00217-09] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Saccharomyces cerevisiae produces extracellular glycerophosphoinositol through phospholipase-mediated turnover of phosphatidylinositol and transports glycerophosphoinositol into the cell upon nutrient limitation. A screening identified the RAS GTPase-activating proteins Ira1 and Ira2 as required for utilization of glycerophosphoinositol as the sole phosphate source, but the RAS/cyclic AMP pathway does not appear to be involved in the growth phenotype. Ira1 and Ira2 affect both the production and transport of glycerophosphoinositol.
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34
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Nunez LR, Jesch SA, Gaspar ML, Almaguer C, Villa-Garcia M, Ruiz-Noriega M, Patton-Vogt J, Henry SA. Cell wall integrity MAPK pathway is essential for lipid homeostasis. J Biol Chem 2008; 283:34204-17. [PMID: 18842580 PMCID: PMC2590691 DOI: 10.1074/jbc.m806391200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 10/02/2008] [Indexed: 11/06/2022] Open
Abstract
The highly conserved yeast cell wall integrity mitogen-activated protein kinase pathway regulates cellular responses to cell wall and membrane stress. We report that this pathway is activated and essential for viability under growth conditions that alter both the abundance and pattern of synthesis and turnover of membrane phospholipids, particularly phosphatidylinositol and phosphatidylcholine. Mutants defective in this pathway exhibit a choline-sensitive inositol auxotrophy, yet fully derepress INO1 and other Opi1p-regulated genes when grown in the absence of inositol. Under these growth conditions, Mpk1p is transiently activated by phosphorylation and stimulates the transcription of known targets of Mpk1p signaling, including genes regulated by the Rlm1p transcription factor. mpk1Delta cells also exhibit severe defects in lipid metabolism, including an abnormal accumulation of phosphatidylcholine, diacylglycerol, triacylglycerol, and free sterols, as well as aberrant turnover of phosphatidylcholine. Overexpression of the NTE1 phospholipase B gene suppresses the choline-sensitive inositol auxotrophy of mpk1Delta cells, whereas overexpression of other phospholipase genes has no effect on this phenotype. These results indicate that an intact cell wall integrity pathway is required for maintaining proper lipid homeostasis in yeast, especially when cells are grown in the absence of inositol.
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Affiliation(s)
- Lilia R Nunez
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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35
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Tanaka K, Fukuda R, Ono Y, Eguchi H, Nagasawa S, Nakatani Y, Watanabe H, Nakanishi H, Taguchi R, Ohta A. Incorporation and remodeling of extracellular phosphatidylcholine with short acyl residues in Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:391-9. [PMID: 18599377 DOI: 10.1016/j.bbalip.2008.06.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 05/17/2008] [Accepted: 06/03/2008] [Indexed: 11/28/2022]
Abstract
The pem1/cho2 pem2/opi3 double mutant of Saccharomyces cerevisiae, which is auxotrophic for choline because of the deficiency in methylation activities of phosphatidylethanolamine, grew in the presence of 0.1 mM dioctanoyl-phosphatidylcholine (diC(8)PC). Analysis of the metabolism of methyl-(13)C-labeled diC(8)PC ((methyl-(13)C)(3)-diC(8)PC) by electrospray ionization tandem mass spectrometry (ESI-MS/MS) revealed that it was rapidly converted to (methyl-(13)C)(3)-PCs containing C16 or C18 acyl chains. (Methyl-(13)C)(3)-8:0-lyso-PC, (methyl-(13)C)(3)-8:0-16:0-PC and (methyl-(13)C)(3)-8:0-16:1-PC, which are the probable intermediate molecular species of acyl chain remodeling, appeared immediately after 5 min of pulse-labeling and decreased during the subsequent chase period. These results indicate that diC(8)PC was taken up by the pem1 pem2 double mutant and that the acyl chains of diC(8)PC were exchanged with longer yeast fatty acids. The temporary appearance of (methyl-(13)C)(3)-8:0-lyso-PC suggests that the remodeling reaction may consist of deacylation and reacylation by phospholipase activities and acyltransferase activities, respectively. The detailed analyses of the structures of (methyl-(13)C)(3)-8:0-16:0-PC and (methyl-(13)C)(3)-8:0-16:1-PC by MS/MS and MS(3) strongly suggest that most (methyl-(13)C)(3)-8:0-16:0-PCs have a C16:0 acyl chain at sn-1 position, whereas (methyl-(13)C)(3)-8:0-16:1-PCs have a C16:1 acyl chain at either sn-1 or sn-2 position in a similar frequency, implying that the initial C16:0 acyl chain substitution prefers the sn-1 position; however, the C16:1 acyl chain substitution starts at both sn-1 and sn-2 positions. The current study provides a pivotal insight into the acyl chain remodeling of phospholipids in yeast.
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Affiliation(s)
- Kunihiko Tanaka
- Department of Biotechnology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
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Siafakas AR, Sorrell TC, Wright LC, Wilson C, Larsen M, Boadle R, Williamson PR, Djordjevic JT. Cell wall-linked cryptococcal phospholipase B1 is a source of secreted enzyme and a determinant of cell wall integrity. J Biol Chem 2007; 282:37508-14. [PMID: 17947228 DOI: 10.1074/jbc.m707913200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phospholipase B (Plb1) is secreted by pathogenic fungi and is a proven virulence determinant in Cryptococcus neoformans. Cell-associated Plb1 is presumptively involved in fungal membrane biogenesis and remodelling. We have also identified it in cryptococcal cell walls. Motif scanning programs predict that Plb1 is attached to cryptococcal membranes via a glycosylphosphatidylinositol (GPI) anchor, which could regulate Plb1 export and secretion. A functional GPI anchor was identified in cell-associated Plb1 by (G)PI-specific phospholipase C (PLC)-induced release of Plb1 from strain H99 membrane rafts and inhibition of GPI anchor synthesis by YW3548, which prevented Plb1 secretion and transport to membranes and cell walls. Plb1 containing beta-1,6-linked glucan was released from H99 (wild-type strain) cell walls by beta-1,3 glucanase, consistent with covalent attachment of Plb1 via beta-1,6-linked glucans to beta-1,3-linked glucan in the central scaffold of the wall. Naturally secreted Plb1 also contained beta-1,6-linked glucan, confirming that it originated from the cell wall. Plb1 maintains cell wall integrity because a H99 deletion mutant, DeltaPLB1, exhibited a morphological defect and was more susceptible than H99 to cell wall disruption by SDS and Congo red. Growth of DeltaPLB1 was unaffected by caffeine, excluding an effect of Plb1 on cell wall biogenesis-related signaling pathways. Environmental (heat) stress caused Plb1 accumulation in cell walls, with loss from membranes and reduced secretion, further supporting the importance of Plb1 in cell wall integrity. This is the first demonstration that Plb1 contributes to fungal survival by maintaining cell wall integrity and that the cell wall is a source of secreted enzyme.
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Affiliation(s)
- A Rosemary Siafakas
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, University of Sydney at Westmead Hospital, NSW, Australia
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Tamaki H, Shimada A, Ito Y, Ohya M, Takase J, Miyashita M, Miyagawa H, Nozaki H, Nakayama R, Kumagai H. LPT1 encodes a membrane-bound O-acyltransferase involved in the acylation of lysophospholipids in the yeast Saccharomyces cerevisiae. J Biol Chem 2007; 282:34288-98. [PMID: 17890783 DOI: 10.1074/jbc.m704509200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phospholipids are major components of cellular membranes that participate in a range of cellular processes. Phosphatidic acid (PA) is a key molecule in the phospholipid biosynthetic pathway. In Saccharomyces cerevisiae, SLC1 has been identified as the gene encoding lysophosphatidic acid acyltransferase, which catalyzes PA synthesis. However, despite the importance of PA, disruption of SLC1 does not affect cell viability (Nagiec, M. M., Wells, G. B., Lester, R. L., and Dickson, R. C. (1993) J. Biol. Chem. 268, 22156-22163). We originally aimed to identify the acetyl-CoA:lyso platelet-activating factor acetyltransferase (lysoPAF AT) gene in yeast. Screening of a complete set of yeast deletion clones (4741 homozygous diploid clones) revealed a single mutant strain, YOR175c, with a defect in lysoPAF AT activity. YOR175c has been predicted to be a member of the membrane-bound O-acyltransferase superfamily, and we designated the gene LPT1. An Lpt1-green fluorescent protein fusion protein localized at the endoplasmic reticulum. Other than lysoPAF AT activity, Lpt1 catalyzed acyltransferase activity with a wide variety of lysophospholipids as acceptors, including lysophosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylglycerol, lysophosphatidylinositol, and lysophosphatidylserine. A liquid chromatography-mass spectrometry analysis indicated that lysophosphatidylcholine and lysophosphatidylethanolamine accumulated in the Deltalpt1 mutant strain. Although the Deltalpt1 mutant strain did not show other detectable defects, the Deltalpt1 Deltaslc1 double mutant strain had a synthetic lethal phenotype. These results indicate that, in concert with Slc1, Lpt1 plays a central role in PA biosynthesis, which is essential for cell viability.
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Affiliation(s)
- Hisanori Tamaki
- Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Japan.
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Tai SL, Snoek I, Luttik MAH, Almering MJH, Walsh MC, Pronk JT, Daran JM. Correlation between transcript profiles and fitness of deletion mutants in anaerobic chemostat cultures of Saccharomyces cerevisiae. MICROBIOLOGY-SGM 2007; 153:877-886. [PMID: 17322208 PMCID: PMC2895221 DOI: 10.1099/mic.0.2006/002873-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The applicability of transcriptomics for functional genome analysis rests on the assumption that global information on gene function can be inferred from transcriptional regulation patterns. This study investigated whether Saccharomyces cerevisiae genes that show a consistently higher transcript level under anaerobic than aerobic conditions do indeed contribute to fitness in the absence of oxygen. Tagged deletion mutants were constructed in 27 S. cerevisiae genes that showed a strong and consistent transcriptional upregulation under anaerobic conditions, irrespective of the nature of the growth-limiting nutrient (glucose, ammonia, sulfate or phosphate). Competitive anaerobic chemostat cultivation showed that only five out of the 27 mutants (eug1Δ, izh2Δ, plb2Δ, ylr413wΔ and yor012wΔ) conferred a significant disadvantage relative to a tagged reference strain. The implications of this study are that: (i) transcriptome analysis has a very limited predictive value for the contribution of individual genes to fitness under specific environmental conditions, and (ii) competitive chemostat cultivation of tagged deletion strains offers an efficient approach to select relevant leads for functional analysis studies.
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Affiliation(s)
- Siew Leng Tai
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Ishtar Snoek
- Institute of Biology Leiden, Leiden University, Leiden, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
| | - Marijke A. H. Luttik
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Marinka J. H. Almering
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Michael C. Walsh
- Heineken Supply Chain, Research and Innovation, Burgemeester Smeetsweg 1, 2380 BB Zoeterwoude, The Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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Benghezal M, Roubaty C, Veepuri V, Knudsen J, Conzelmann A. SLC1 and SLC4 encode partially redundant acyl-coenzyme A 1-acylglycerol-3-phosphate O-acyltransferases of budding yeast. J Biol Chem 2007; 282:30845-55. [PMID: 17675291 DOI: 10.1074/jbc.m702719200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidic acid is the intermediate, from which all glycerophospholipids are synthesized. In yeast, it is generated from lysophosphatidic acid, which is acylated by Slc1p, an sn-2-specific, acyl-coenzyme A-dependent 1-acylglycerol-3-phosphate O-acyltransferase. Deletion of SLC1 is not lethal and does not eliminate all microsomal 1-acylglycerol-3-phosphate O-acyltransferase activity, suggesting that an additional enzyme may exist. Here we show that SLC4 (Yor175c), a gene of hitherto unknown function, encodes a second 1-acyl-sn-glycerol-3-phosphate acyltransferase. SLC4 harbors a membrane-bound O-acyltransferase motif and down-regulation of SLC4 strongly reduces 1-acyl-sn-glycerol-3-phosphate acyltransferase activity in microsomes from slc1Delta cells. The simultaneous deletion of SLC1 and SLC4 is lethal. Mass spectrometric analysis of lipids from slc1Delta and slc4Delta cells demonstrates that in vivo Slc1p and Slc4p generate almost the same glycerophospholipid profile. Microsomes from slc1Delta and slc4Delta cells incubated with [14C]oleoyl-coenzyme A in the absence of lysophosphatidic acid and without CTP still incorporate the label into glycerophospholipids, indicating that Slc1p and Slc4p can also use endogenous lysoglycerophospholipids as substrates. However, the lipid profiles generated by microsomes from slc1Delta and slc4Delta cells are different, and this suggests that Slc1p and Slc4p have a different substrate specificity or have access to different lyso-glycerophospholipid substrates because of a different subcellular location. Indeed, affinity-purified Slc1p displays Mg2+-dependent acyltransferase activity not only toward lysophosphatidic acid but also lyso forms of phosphatidylserine and phosphatidylinositol. Thus, Slc1p and Slc4p may not only be active as 1-acylglycerol-3-phosphate O-acyltransferases but also be involved in fatty acid exchange at the sn-2-position of mature glycerophospholipids.
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Affiliation(s)
- Mohammed Benghezal
- Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
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40
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Richmond G, Smith T. The role and characterization of phospholipase A1 in mediating lysophosphatidylcholine synthesis in Trypanosoma brucei. Biochem J 2007; 405:319-29. [PMID: 17402937 PMCID: PMC1904526 DOI: 10.1042/bj20070193] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Lysophospholipids are ubiquitous intermediates in a variety of metabolic and signalling pathways in eukaryotic cells. We have reported recently that lysoglycerophosphatidylcholine (lyso-GPCho) synthesis in the insect form of the ancient eukaryote Trypanosoma brucei is mediated by a novel phospholipase A1 (TbPLA1). In the present study, we show that despite equal levels of TbPLA1 gene expression in wild-type insect and bloodstream trypomastigotes, both TbPLA1 enzyme levels and lysoGPCho metabolites are approx. 3-fold higher in the bloodstream form. Both of these parasite stages synthesize identical molecular species of lysoGPCho. TbPLA1 null mutants in the bloodstream form of the parasite are viable, but are deficient in lysoGPCho synthesis, a defect that can be overcome by the expression of an ectopic copy of TbPLA1. The biochemical attributes of TbPLA1-mediated lysoGPCho synthesis were examined in vitro using recombinant TbPLA1. Although TbPLA1 possesses an active-site serine residue, it is insensitive to serine-modifying reagents, such as di-isopropyl fluorophosphate and PMSF, a characteristic shared by lipases that possess lid-sheltered catalytic triads. TbPLA1 does not require metal co-factors for activity, but it does require interfacial activation prior to catalysis. Results from size-exclusion chromatography and binding kinetics analysis revealed that TbPLA1 activation by Triton X-100/GPCho mixed micelle surfaces was not specific and did not require the pre-formation of a specific enzyme-substrate complex to achieve surface binding.
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Affiliation(s)
- Gregory S. Richmond
- Wellcome Trust Biocentre, Division of Biological Chemistry and Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
| | - Terry K. Smith
- Wellcome Trust Biocentre, Division of Biological Chemistry and Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
- To whom correspondence should be addressed (email )
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41
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Griac P. Sec14 related proteins in yeast. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:737-45. [PMID: 17395532 DOI: 10.1016/j.bbalip.2007.02.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2006] [Revised: 02/20/2007] [Accepted: 02/21/2007] [Indexed: 11/18/2022]
Abstract
Lipid transport between membranes of eukaryotic organisms represents an essential aspect of organelle biogenesis. This transport must be strictly selective and directional to assure specific lipid composition of individual membranes. Despite the intensive research effort in the last few years, our understanding of how lipids are sorted and moved within cells is still rather limited. Evidence indicates that at least some of the mechanisms generating and maintaining non-random distribution of lipids in cells are linked to the action of phosphatidylinositol transfer proteins (PITPs). The major PITP in yeast Saccharomyces cerevisiae, Sec14p, is essential in promoting Golgi secretory function by modulating of its membrane lipid composition. This review focuses on a group of five yeast proteins that share significant sequence homology with Sec14p. Based on this sequence identity, they were termed Sfh (Sec fourteen homologue) proteins. It is a diverse group of proteins with distinct subcellular localizations and varied physiological functions related to lipid metabolism, phosphoinositide mediated signaling and membrane trafficking.
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Affiliation(s)
- Peter Griac
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 900 28 Ivanka pri Dunaji, Slovakia.
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42
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Fernández-Murray JP, McMaster CR. Phosphatidylcholine synthesis and its catabolism by yeast neuropathy target esterase 1. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:331-6. [PMID: 16731034 DOI: 10.1016/j.bbalip.2006.04.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 04/06/2006] [Accepted: 04/11/2006] [Indexed: 11/22/2022]
Abstract
Phosphatidylcholine (PtdCho) is the major phospholipid component of eukaryotic membranes and deciphering the molecular mechanisms regulating PtdCho homeostasis is necessary to fully understand many pathophysiological situations where PtdCho metabolism is altered. This concept is illustrated in this review by summarizing recent evidence on Nte1p, a yeast endoplasmic reticulum resident phospholipase B that deacylates PtdCho producing intracellular glycerophosphocholine. The mammalian and Drosophila homologues, neuropathy target esterase and swiss cheese, respectively, have been implicated in normal brain development with increased intracytoplasmic vesicularization and multilayered membrane stacks as cytological signatures of their absence. Consistent with a role in lipid and membrane homeostasis, Nte1p-mediated PtdCho deacylation is strongly affected by Sec14p, a component of the yeast secretory machinery characterized by its ability to interface between lipid metabolism and vesicular trafficking. The preference of Nte1p toward PtdCho produced through the CDP-choline pathway and the downstream production of choline by the Gde1p glycerophosphodiesterase for resynthesis of PtdCho by the CDP-choline pathway are also highlighted.
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Affiliation(s)
- J Pedro Fernández-Murray
- Atlantic Research Centre, Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4H7
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43
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Matsumoto MT, Fusco-Almeida AM, Baeza LC, Melhem MDSC, Medes-Giannini MJS. Genotyping, serotyping and determination of mating-type of Cryptococcus neoformans clinical isolates from São Paulo State, Brazil. Rev Inst Med Trop Sao Paulo 2007; 49:41-7. [PMID: 17384819 DOI: 10.1590/s0036-46652007000100008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Accepted: 08/16/2006] [Indexed: 11/22/2022] Open
Abstract
The basidiomycetous yeast Cryptococcus neoformans is an important fungal pathogen mainly in immunocompromised patients. In this study, 47 clinical isolates of C. neoformans from regions of São Paulo State were studied serologically by using the Crypto Check Iatron RM 304-K kit, their genetic diversity was estimated by PCR-fingerprinting with a microsatellite-specific sequence (GACA)4, RAPD with primer 6 (Amersham Pharmacia Biotech), PCR-restriction fragment length polymorphism (RFLP) analysis of the phospholipase B gene (PLB1) digested with AvaI and mating type analysis by PCR. All 47 strains isolated from HIV positive patients included in this study were serotype A and MATalpha. The majority of the isolates (45/47) were VNI and only two were VNII by PCR-fingerprinting and PCR-RFLP analysis. High degree of homogeneity was observed when (GACA)4 was used, being highly correlated (> 0.9). In contrast, the RAPD analysis was more heterogeneous with higher number of molecular profiles. By PCR-RFLP, no new molecular type was found, enhancing the suggestion that the differences based on conserved gene as PLB1, can be resultant of ongoing divergent evolution within the C. neoformans complex, into the current eight subtypes. Our results furnish new information on the molecular epidemiology of C. neoformans in the southeast region of Brazil.
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Affiliation(s)
- Marcelo Teruyuki Matsumoto
- Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, Araraquara, SP, Brasil
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44
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Tevzadze GG, Pierce JV, Esposito RE. Genetic evidence for a SPO1-dependent signaling pathway controlling meiotic progression in yeast. Genetics 2006; 175:1213-27. [PMID: 17179081 PMCID: PMC1840080 DOI: 10.1534/genetics.106.069252] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The yeast spindle pole body (SPB) plays a unique role in meiosis, initiating both spindle assembly and prospore membrane synthesis. SPO1, induced early in development, encodes a meiosis-specific phospholipase B (PLB) homolog required at three stages of SPB morphogenesis: MI, MII, and spore formation. Here we report in-depth analysis of the SPO1 gene including its transcriptional control by regulators of early gene expression, protein localization to the ER lumen and periplasmic space, and molecular genetic studies of its role in meiosis. Evidence is presented that multiple arrest points in spo1Delta occur independently, demonstrating that Spo1 acts at distinct steps. Loss of Spo1 is suppressed by high-copy glycosylphosphatidylinositol (GPI) proteins, dependent on sequence, timing, and strength of induction in meiosis. Since phosphatidylinositol (PI) serves as both an anchor component and a lipase substrate, we hypothesized that GPI-protein expression might substitute for Spo1 by decreasing levels of its potential substrates, PI and phosphatidylinositol phosphates (PIPs). Partial spo1Delta complementation by PLB3 (encoding a unique PLB capable of cleaving PI) and relatively strong Spo1 binding to PI(4)P derivatives (via a novel N-terminal lysine-rich fragment essential for Spo1 function) are consistent with this view. Epistasis of SPO1 mutations to those in SPO14 (encoding a PLD involved in signaling) and physical interaction of Spo1 with Spo23, a protein regulating PI synthesis required for wild-type sporulation, further support this notion. Taken together these findings implicate PI and/or PIPs in Spo1 function and suggest the existence of a novel Spo1-dependent meiosis-specific signaling pathway required for progression of MI, MII, and spore formation via regulation of the SPB.
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Affiliation(s)
- Gela G Tevzadze
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637, USA
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45
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Köhler GA, Brenot A, Haas-Stapleton E, Agabian N, Deva R, Nigam S. Phospholipase A2 and phospholipase B activities in fungi. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1761:1391-9. [PMID: 17081801 PMCID: PMC2077850 DOI: 10.1016/j.bbalip.2006.09.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 09/20/2006] [Accepted: 09/25/2006] [Indexed: 10/24/2022]
Abstract
As saprophytes or disease causing microorganisms, fungi acquire nutrients from dead organic material or living host organisms. Lipids as structural components of cell membranes and storage compartments play an important role as energy-rich food source. In recent years, it also has become clear that lipids have a wide range of bioactive properties including signal transduction and cell to cell communication. Thus, it is not surprising that fungi possess a broad range of hydrolytic enzymes that attack neutral lipids and phospholipids. Especially during infection of a mammalian host, phospholipase A(2) (PLA(2)) enzymes released by fungi could play important roles not only for nutrient acquisition and tissue invasion, but for intricate modulation of the host's immune response. Sequencing of fungal genomes has revealed a wide range of genes encoding PLA(2) activities in fungi. We are just beginning to become aware of the significance these enzymes could have for the fungal cells and their interaction with the host.
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Affiliation(s)
- Gerwald A. Köhler
- Department of Cell and Tissue Biology, University of California, San Francisco, U.S.A
| | - Audrey Brenot
- Department of Cell and Tissue Biology, University of California, San Francisco, U.S.A
| | - Eric Haas-Stapleton
- Department of Cell and Tissue Biology, University of California, San Francisco, U.S.A
| | - Nina Agabian
- Department of Cell and Tissue Biology, University of California, San Francisco, U.S.A
| | - Rupal Deva
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Charité - Univ.-Klinikum Benjamin Franklin, D-12200 Berlin, Germany
| | - Santosh Nigam
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Charité - Univ.-Klinikum Benjamin Franklin, D-12200 Berlin, Germany
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de Kroon AIPM. Metabolism of phosphatidylcholine and its implications for lipid acyl chain composition in Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1771:343-52. [PMID: 17010666 DOI: 10.1016/j.bbalip.2006.07.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 07/28/2006] [Accepted: 07/31/2006] [Indexed: 11/29/2022]
Abstract
Phosphatidylcholine (PC) is a very abundant membrane lipid in most eukaryotes including the model organism Saccharomyces cerevisiae. Consequently, the molecular species profile of PC, i.e. the ensemble of PC molecules with acyl chains differing in number of carbon atoms and double bonds, is important in determining the physical properties of eukaryotic membranes, and should be tightly regulated. In this review current insights in the contributions of biosynthesis, turnover, and remodeling by acyl chain exchange to the maintenance of PC homeostasis at the level of the molecular species in yeast are summarized. In addition, the phospholipid class-specific changes in membrane acyl chain composition induced by PC depletion are discussed, which identify PC as key player in a novel regulatory mechanism balancing the proportions of bilayer and non-bilayer lipids in yeast.
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Affiliation(s)
- Anton I P M de Kroon
- Department Biochemistry of Membranes, Bijvoet Institute and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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Theiss S, Ishdorj G, Brenot A, Kretschmar M, Lan CY, Nichterlein T, Hacker J, Nigam S, Agabian N, Köhler GA. Inactivation of the phospholipase B gene PLB5 in wild-type Candida albicans reduces cell-associated phospholipase A2 activity and attenuates virulence. Int J Med Microbiol 2006; 296:405-20. [PMID: 16759910 PMCID: PMC2481510 DOI: 10.1016/j.ijmm.2006.03.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 03/15/2006] [Accepted: 03/15/2006] [Indexed: 11/24/2022] Open
Abstract
Phospholipases are critical for modification and redistribution of lipid substrates, membrane remodeling and microbial virulence. Among the many different classes of phospholipases, fungal phospholipase B (Plb) proteins show the broadest range of substrate specificity and hydrolytic activity, hydrolyzing acyl ester bonds in phospholipids and lysophospholipids and further catalyzing lysophospholipase-transacylase reactions. The genome of the opportunistic fungal pathogen Candida albicans encodes a PLB multigene family with five putative members; we present the first characterization of this group of potential virulence determinants. CaPLB5, the third member of this multigene family characterized herein is a putative secretory protein with a predicted GPI-anchor attachment site. Real-time RT-PCR gene expression analysis of CaPLB5 and the additional CaPLB gene family members revealed that filamentous growth and physiologically relevant environmental conditions are associated with increased PLB gene activity. The phenotypes expressed by null mutant and revertant strains of CaPLB5 indicate that this lipid hydrolase plays an important role for cell-associated phospholipase A(2) activity and in vivo organ colonization.
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Affiliation(s)
- Stephanie Theiss
- Zentrum für Infektionsforschung, Universität Würzburg, Würzburg, Germany
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
| | - Ganchimeg Ishdorj
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Universitäsklinikum Benjamin Franklin, Free University Berlin, Berlin, Germany
| | - Audrey Brenot
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | | | - Chung-Yu Lan
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Thomas Nichterlein
- Mikrobiologie und Hygiene, Klinikum der Stadt Mannheim, Mannheim, Germany
| | - Jörg Hacker
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Würzburg, Germany
| | - Santosh Nigam
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Universitäsklinikum Benjamin Franklin, Free University Berlin, Berlin, Germany
| | - Nina Agabian
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Gerwald A. Köhler
- Zentrum für Infektionsforschung, Universität Würzburg, Würzburg, Germany
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Corresponding author: Gerwald A. Köhler, Ph.D., Department of Biochemistry & Microbiology, Oklahoma State University, Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107-1898 U.S.A.. Phone: ++ 1 918 561 8302; Fax: ++ 1 918 561 5798; E-mail:
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Kiewietdejonge A, Pitts M, Cabuhat L, Sherman C, Kladwang W, Miramontes G, Floresvillar J, Chan J, Ramirez RM. Hypersaline stress induces the turnover of phosphatidylcholine and results in the synthesis of the renal osmoprotectant glycerophosphocholine in Saccharomyces cerevisiae. FEMS Yeast Res 2006; 6:205-17. [PMID: 16487344 DOI: 10.1111/j.1567-1364.2006.00030.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The role of phosphatidylcholine turnover during hypersaline stress is investigated in Saccharomyces cerevisiae. In the wild-type strain, 2180-1A hypersaline stress induced the rapid turnover of phosphatidylcholine, a major membrane lipid. Yeast cells were grown in the presence of [14C]-choline to label phosphatidylcholine. Upon shifting the cells to medium with 0.8 M NaCl, phosphatidylcholine levels were diminished by c. 30% within 20 min to yield glycerophosphocholine, a methylamine osmoprotectant that has been previously identified in renal cells. High-performance liquid chromatography studies showed that osmotically mediated glycerophosphocholine production was enhanced if 10 mM choline was added as a supplement to synthetic dextrose medium with 1.6 M NaCl, but glycine betaine was not detected. Enhanced glycerophosphocholine production also correlated with improved growth in media containing 1.6 M NaCl and choline. Enhanced growth is specific to methylamines: salt-stressed cells supplemented with 10 mM choline or glycine betaine showed enhanced growth relative to unsupplemented control cultures, but other additives had no effect on growth or adversely affected it. Nutritional effects are ruled out because yeast cannot use choline or glycine betaine as carbon or nitrogen sources in normal or high-salt medium. Finally, enhanced growth in hypersaline media with choline or glycine betaine is dependent on the choline permease Hnm1. These results in yeast highlight a similarity with mammalian renal cells, namely that phosphatidylcholine turnover contributes to osmotic adaptation via synthesis of the osmoprotectant glycerophosphocholine.
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Patton-Vogt J. Transport and metabolism of glycerophosphodiesters produced through phospholipid deacylation. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1771:337-42. [PMID: 16781190 DOI: 10.1016/j.bbalip.2006.04.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 04/20/2006] [Accepted: 04/26/2006] [Indexed: 10/25/2022]
Abstract
Phospholipid deacylation results in the formation of glycerophosphodiesters and free fatty acids. In Saccharomyces cerevisiae, four gene products with phospholipase B (deacylating) activity have been characterized (PLB1, PLB2, PLB3, NTE1), and those activities account for most, if not all, of the glycerophosphodiester production observed to date. The glycerophosphodiesters themselves are hydrolyzed into glycerol-3-phosphate and the corresponding alcohol by glycerophosphodiester phosphodiesterases. Although only one glycerophosphodiester phosphodiesterase-encoding gene (GDE1) has been characterized in S. cerevisiae, others certainly exist. Both internal and external glycerophosphodiesters (primarily glycerophosphocholine and glycerophosphoinositol) are formed as a result of phospholipid turnover in S. cerevisiae. A permease encoded by the GIT1 gene imports extracellular glycerophosphodiesters across the plasma membrane, where their hydrolytic products can provide crucial nutrients such as inositol, choline, and phosphate to the cell. The importance of this metabolic pathway in various aspects of S. cerevisiae cell physiology is being explored.
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Affiliation(s)
- Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282, USA.
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Johanson K, Allen PL, Gonzalez-Villalobos RA, Baker CB, D'Elia R, Hammond TG. Gene expression and survival changes inSaccharomyces cerevisiae during suspension culture. Biotechnol Bioeng 2006; 93:1050-9. [PMID: 16440349 DOI: 10.1002/bit.20810] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This study explores the connection between changes in gene expression and the genes that determine strain survival during suspension culture, using the model eukaryotic organism, Saccharomyces cerevisiae. The Saccharomyces cerevisiae homozygous diploid deletion pool (HDDP), and the BY4743 parental strain were grown for 18 h in a rotating wall vessel (RWV), a suspension culture device optimized to minimize the delivered shear. In addition to the reduced shear conditions, the RWVs were also placed in a static position or in a shaker in order to change the amount of shear stress on the cells. Using simple linear regression, it was found that there were 140 differentially expressed genes for which >70% of the variation can be explained by shear stress alone. A significant number of these genes are involved in catalytic activity. In the HDDP, shear stress was associated with significant survival changes in 15 deletion strains (R(2>) > 0.7) Interestingly, both analyses uncovered changes in the ribosomal protein machinery. Comparing the changes in gene expression and strain survival under the different shear conditions allows for the insights into the molecular mechanisms behind the cells response to shear stress. This in turn can provide information for the optimization of suspension culture.
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Affiliation(s)
- Kelly Johanson
- Nephrology Section, Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA
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