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Wang Y, Wakelam MJO, Bankaitis VA, McDermott MI. The wide world of non-mammalian phospholipase D enzymes. Adv Biol Regul 2024; 91:101000. [PMID: 38081756 DOI: 10.1016/j.jbior.2023.101000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 02/25/2024]
Abstract
Phospholipase D (PLD) hydrolyses phosphatidylcholine (PtdCho) to produce free choline and the critically important lipid signaling molecule phosphatidic acid (PtdOH). Since the initial discovery of PLD activities in plants and bacteria, PLDs have been identified in a diverse range of organisms spanning the taxa. While widespread interest in these proteins grew following the discovery of mammalian isoforms, research into the PLDs of non-mammalian organisms has revealed a fascinating array of functions ranging from roles in microbial pathogenesis, to the stress responses of plants and the developmental patterning of flies. Furthermore, studies in non-mammalian model systems have aided our understanding of the entire PLD superfamily, with translational relevance to human biology and health. Increasingly, the promise for utilization of non-mammalian PLDs in biotechnology is also being recognized, with widespread potential applications ranging from roles in lipid synthesis, to their exploitation for agricultural and pharmaceutical applications.
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Affiliation(s)
- Y Wang
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Microbiology, University of Washington, Seattle, WA98109, USA
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX, 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - M I McDermott
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA.
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2
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Kwiatek JM, Gutierrez B, Izgu EC, Han GS, Carman GM. Phosphatidic acid mediates the Nem1-Spo7/Pah1 phosphatase cascade in yeast lipid synthesis. J Lipid Res 2022; 63:100282. [DOI: 10.1016/j.jlr.2022.100282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 10/31/2022] Open
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3
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Holič R, Šťastný D, Griač P. Sec14 family of lipid transfer proteins in yeasts. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158990. [PMID: 34118432 DOI: 10.1016/j.bbalip.2021.158990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/25/2022]
Abstract
The hydrophobicity of lipids prevents their free movement across the cytoplasm. To achieve highly heterogeneous and precisely regulated lipid distribution in different cellular membranes, lipids are transported by lipid transfer proteins (LTPs) in addition to their transport by vesicles. Sec14 family is one of the most extensively studied groups of LTPs. Here we provide an overview of Sec14 family of LTPs in the most studied yeast Saccharomyces cerevisiae as well as in other selected non-Saccharomyces yeasts-Schizosaccharomyces pombe, Kluyveromyces lactis, Candida albicans, Candida glabrata, Cryptococcus neoformans, and Yarrowia lipolytica. Discussed are specificities of Sec14-domain LTPs in various yeasts, their mode of action, subcellular localization, and physiological function. In addition, quite few Sec14 family LTPs are target of antifungal drugs, serve as modifiers of drug resistance or influence virulence of pathologic yeasts. Thus, they represent an important object of study from the perspective of human health.
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Affiliation(s)
- Roman Holič
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Dominik Šťastný
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Peter Griač
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia.
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4
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Lete MG, Tripathi A, Chandran V, Bankaitis VA, McDermott MI. Lipid transfer proteins and instructive regulation of lipid kinase activities: Implications for inositol lipid signaling and disease. Adv Biol Regul 2020; 78:100740. [PMID: 32992233 PMCID: PMC7986245 DOI: 10.1016/j.jbior.2020.100740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 05/17/2023]
Abstract
Cellular membranes are critical platforms for intracellular signaling that involve complex interfaces between lipids and proteins, and a web of interactions between a multitude of lipid metabolic pathways. Membrane lipids impart structural and functional information in this regulatory circuit that encompass biophysical parameters such as membrane thickness and fluidity, as well as chaperoning the interactions of protein binding partners. Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play key roles in intracellular membrane signaling, and these involvements are translated into an impressively diverse set of biological outcomes. The phosphatidylinositol transfer proteins (PITPs) are key regulators of phosphoinositide signaling. Found in a diverse array of organisms from plants, yeast and apicomplexan parasites to mammals, PITPs were initially proposed to be simple transporters of lipids between intracellular membranes. It now appears increasingly unlikely that the soluble versions of these proteins perform such functions within the cell. Rather, these serve to facilitate the activity of intrinsically biologically insufficient inositol lipid kinases and, in so doing, promote diversification of the biological outcomes of phosphoinositide signaling. The central engine for execution of such functions is the lipid exchange cycle that is a fundamental property of PITPs. How PITPs execute lipid exchange remains very poorly understood. Molecular dynamics simulation approaches are now providing the first atomistic insights into how PITPs, and potentially other lipid-exchange/transfer proteins, operate.
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Affiliation(s)
- Marta G Lete
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Institute Biofisika (UPV/EHU, CSIC) and University of the Basque Country, Leioa, Spain
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vijay Chandran
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77840, USA
| | - Mark I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA.
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Aznar-Moreno JA, Venegas-Calerón M, Du ZY, Garcés R, Tanner JA, Chye ML, Martínez-Force E, Salas JJ. Characterization and function of a sunflower (Helianthus annuus L.) Class II acyl-CoA-binding protein. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 300:110630. [PMID: 33180709 DOI: 10.1016/j.plantsci.2020.110630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 05/13/2023]
Abstract
Acyl-CoA-binding proteins (ACBP) bind to long-chain acyl-CoA esters and phospholipids, enhancing the activity of different acyltransferases in animals and plants. Nevertheless, the role of these proteins in the synthesis of triacylglycerols (TAGs) remains unclear. Here, we cloned a cDNA encoding HaACBP1, a Class II ACBP from sunflower (Helianthus annuus), one of the world's most important oilseed crop plants. Transcriptome analysis of this gene revealed strong expression in developing seeds from 16 to 30 days after flowering. The recombinant protein (rHaACBP1) was expressed in Escherichia coli and purified to be studied by in vitro isothermal titration calorimetry and for phospholipid binding. Its high affinity for saturated palmitoyl-CoA (16:0-CoA; KD 0.11 μM) and stearoyl-CoA (18:0-CoA; KD 0.13 μM) esters suggests that rHaACBP1 could act in acyl-CoA transfer pathways that involve saturated acyl derivatives. Furthermore, rHaACBP1 also binds to both oleoyl-CoA (18:1-CoA; KD 6.4 μM) and linoleoyl-CoA (18:2-CoA; KD 21.4 μM) esters, the main acyl-CoA substrates used to synthesise the TAGs that accumulate in sunflower seeds. Interestingly, rHaACBP1 also appears to bind to different species of phosphatidylcholines (dioleoyl-PC and dilinoleoyl-PC), glycerolipids that are also involved in TAG synthesis, and while it interacts with dioleoyl-PA, this is less prominent than its binding to the PC derivative. Expression of rHaACBP in yeast alters its fatty acid composition, as well as the composition and size of the host acyl-CoA pool. These results suggest that HaACBP1 may potentially fulfil a role in the transport and trafficking of acyl-CoAs during sunflower seed development.
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Affiliation(s)
- Jose A Aznar-Moreno
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Mónica Venegas-Calerón
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013, Sevilla, Spain
| | - Zhi-Yan Du
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Rafael Garcés
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013, Sevilla, Spain
| | - Julian A Tanner
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Enrique Martínez-Force
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013, Sevilla, Spain
| | - Joaquín J Salas
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013, Sevilla, Spain.
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6
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Zaman MF, Nenadic A, Radojičić A, Rosado A, Beh CT. Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex. Front Cell Dev Biol 2020; 8:675. [PMID: 32793605 PMCID: PMC7387695 DOI: 10.3389/fcell.2020.00675] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/03/2020] [Indexed: 12/31/2022] Open
Abstract
Membrane contact sites between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM) provide a direct conduit for small molecule transfer and signaling between the two largest membranes of the cell. Contact is established through ER integral membrane proteins that physically tether the two membranes together, though the general mechanism is remarkably non-specific given the diversity of different tethering proteins. Primary tethers including VAMP-associated proteins (VAPs), Anoctamin/TMEM16/Ist2p homologs, and extended synaptotagmins (E-Syts), are largely conserved in most eukaryotes and are both necessary and sufficient for establishing ER-PM association. In addition, other species-specific ER-PM tether proteins impart unique functional attributes to both membranes at the cell cortex. This review distils recent functional and structural findings about conserved and species-specific tethers that form ER-PM contact sites, with an emphasis on their roles in the coordinate regulation of lipid metabolism, cellular structure, and responses to membrane stress.
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Affiliation(s)
- Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Ana Radojičić
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,The Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
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7
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Kwiatek JM, Han GS, Carman GM. Phosphatidate-mediated regulation of lipid synthesis at the nuclear/endoplasmic reticulum membrane. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158434. [PMID: 30910690 PMCID: PMC6755077 DOI: 10.1016/j.bbalip.2019.03.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 03/14/2019] [Indexed: 12/11/2022]
Abstract
In yeast and higher eukaryotes, phospholipids and triacylglycerol are derived from phosphatidate at the nuclear/endoplasmic reticulum membrane. In de novo biosynthetic pathways, phosphatidate is channeled into membrane phospholipids via its conversion to CDP-diacylglycerol. Its dephosphorylation to diacylglycerol is required for the synthesis of triacylglycerol as well as for the synthesis of phosphatidylcholine and phosphatidylethanolamine via the Kennedy pathway. In addition to the role of phosphatidate as a precursor, it is a regulatory molecule in the transcriptional control of phospholipid synthesis genes via the Henry regulatory circuit. Pah1 phosphatidate phosphatase and Dgk1 diacylglycerol kinase are key players that function counteractively in the control of the phosphatidate level at the nuclear/endoplasmic reticulum membrane. Loss of Pah1 phosphatidate phosphatase activity not only affects triacylglycerol synthesis but also disturbs the balance of the phosphatidate level, resulting in the alteration of lipid synthesis and related cellular defects. The pah1Δ phenotypes requiring Dgk1 diacylglycerol kinase exemplify the importance of the phosphatidate level in the misregulation of cellular processes. The catalytic function of Pah1 requires its translocation from the cytoplasm to the nuclear/endoplasmic reticulum membrane, which is regulated through its phosphorylation in the cytoplasm by multiple protein kinases as well as through its dephosphorylation by the membrane-associated Nem1-Spo7 protein phosphatase complex. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
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Affiliation(s)
- Joanna M Kwiatek
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA.
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8
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Thakur R, Naik A, Panda A, Raghu P. Regulation of Membrane Turnover by Phosphatidic Acid: Cellular Functions and Disease Implications. Front Cell Dev Biol 2019; 7:83. [PMID: 31231646 PMCID: PMC6559011 DOI: 10.3389/fcell.2019.00083] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/03/2019] [Indexed: 01/23/2023] Open
Abstract
Phosphatidic acid (PA) is a simple glycerophospholipid with a well-established role as an intermediate in phospholipid biosynthesis. In addition to its role in lipid biosynthesis, PA has been proposed to act as a signaling molecule that modulates several aspects of cell biology including membrane transport. PA can be generated in eukaryotic cells by several enzymes whose activity is regulated in the context of signal transduction and enzymes that can metabolize PA thus terminating its signaling activity have also been described. Further, several studies have identified PA binding proteins and changes in their activity are proposed to be mediators of the signaling activity of this lipid. Together these enzymes and proteins constitute a PA signaling toolkit that mediates the signaling functions of PA in cells. Recently, a number of novel genetic models for the analysis of PA function in vivo and analytical methods to quantify PA levels in cells have been developed and promise to enhance our understanding of PA functions. Studies of several elements of the PA signaling toolkit in a single cell type have been performed and are presented to provide a perspective on our understanding of the biochemical and functional organization of pools of PA in a eukaryotic cell. Finally, we also provide a perspective on the potential role of PA in human disease, synthesizing studies from model organisms, human disease genetics and analysis using recently developed PLD inhibitors.
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Affiliation(s)
- Rajan Thakur
- National Centre for Biological Sciences-TIFR, Bengaluru, India
| | - Amruta Naik
- National Centre for Biological Sciences-TIFR, Bengaluru, India
| | - Aniruddha Panda
- National Centre for Biological Sciences-TIFR, Bengaluru, India
| | - Padinjat Raghu
- National Centre for Biological Sciences-TIFR, Bengaluru, India
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9
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Panagabko C, Baptist M, Atkinson J. In vitro lipid transfer assays of phosphatidylinositol transfer proteins provide insight into the in vivo mechanism of ligand transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:619-630. [PMID: 30543784 DOI: 10.1016/j.bbamem.2018.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 11/16/2022]
Abstract
Fluorescence resonance energy transfer (FRET) assays and membrane binding determinations were performed using three phosphatidylinositol transfer proteins, including the yeast Sec14 and two mammalian proteins PITPα and PITPβ. These proteins were able to specifically bind the fluorescent phosphatidylcholine analogue NBD-PC ((2-(12-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine)) and to transfer it to small unilamellar vesicles (SUVs). Rate constants for transfer to vesicles comprising 100% PC were slower for all proteins than when increasing percentages of phosphatidylinositol were incorporated into the same SUVs. The rates of ligand transfer by Sec14 were insensitive to the inclusion of equimolar amounts of another anionic phospholipid phosphatidylserine (PS), but the rates of ligand transfer by both mammalian PITPs were strikingly enhanced by the inclusion of phosphatidic acid (PA) in the receptor SUV. Binding of Sec14 to immobilized bilayers was substantial, while that of PITPα and PITPβ was 3-7 times weaker than Sec14 depending on phospholipid composition. When small proportions of the phosphoinositide PI(4)P were included in receptor SUVs (either with PI or not), Sec14 showed substantially increased rates of NBD-PC pick-up, whereas the PITPs were unaffected. The data are supportive of a role for PITPβ as functional PI transfer protein in vivo, but that Sec14 likely has a more elaborate function.
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Affiliation(s)
- Candace Panagabko
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario L2A 3S1, Canada
| | - Matilda Baptist
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario L2A 3S1, Canada
| | - Jeffrey Atkinson
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario L2A 3S1, Canada.
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10
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Grabon A, Bankaitis VA, McDermott MI. The interface between phosphatidylinositol transfer protein function and phosphoinositide signaling in higher eukaryotes. J Lipid Res 2018; 60:242-268. [PMID: 30504233 DOI: 10.1194/jlr.r089730] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides are key regulators of a large number of diverse cellular processes that include membrane trafficking, plasma membrane receptor signaling, cell proliferation, and transcription. How a small number of chemically distinct phosphoinositide signals are functionally amplified to exert specific control over such a diverse set of biological outcomes remains incompletely understood. To this end, a novel mechanism is now taking shape, and it involves phosphatidylinositol (PtdIns) transfer proteins (PITPs). The concept that PITPs exert instructive regulation of PtdIns 4-OH kinase activities and thereby channel phosphoinositide production to specific biological outcomes, identifies PITPs as central factors in the diversification of phosphoinositide signaling. There are two evolutionarily distinct families of PITPs: the Sec14-like and the StAR-related lipid transfer domain (START)-like families. Of these two families, the START-like PITPs are the least understood. Herein, we review recent insights into the biochemical, cellular, and physiological function of both PITP families with greater emphasis on the START-like PITPs, and we discuss the underlying mechanisms through which these proteins regulate phosphoinositide signaling and how these actions translate to human health and disease.
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Affiliation(s)
- Aby Grabon
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Vytas A Bankaitis
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Mark I McDermott
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
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11
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Mysyakina IS, Sergeeva YE, Bokareva DA. Lipid composition of the spores of zygomycetous and ascomycetous fungi during cessation of the exogenous dormancy state. Microbiology (Reading) 2018. [DOI: 10.1134/s0026261718010125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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McMaster CR. From yeast to humans - roles of the Kennedy pathway for phosphatidylcholine synthesis. FEBS Lett 2017; 592:1256-1272. [PMID: 29178478 DOI: 10.1002/1873-3468.12919] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/20/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022]
Abstract
The major phospholipid present in most eukaryotic membranes is phosphatidylcholine (PC), comprising ~ 50% of phospholipid content. PC metabolic pathways are highly conserved from yeast to humans. The main pathway for the synthesis of PC is the Kennedy (CDP-choline) pathway. In this pathway, choline is converted to phosphocholine by choline kinase, phosphocholine is metabolized to CDP-choline by the rate-determining enzyme for this pathway, CTP:phosphocholine cytidylyltransferase, and cholinephosphotransferase condenses CDP-choline with diacylglycerol to produce PC. This Review discusses how PC synthesis via the Kennedy pathway is regulated, its role in cellular and biological processes, as well as diseases known to be associated with defects in PC synthesis. Finally, we present the first model for the making of a membrane via PC synthesis.
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13
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Liu LK, Choudhary V, Toulmay A, Prinz WA. An inducible ER-Golgi tether facilitates ceramide transport to alleviate lipotoxicity. J Cell Biol 2016; 216:131-147. [PMID: 28011845 PMCID: PMC5223604 DOI: 10.1083/jcb.201606059] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/20/2016] [Accepted: 12/07/2016] [Indexed: 01/27/2023] Open
Abstract
Liu et al. show that ER–Golgi tethering increases during ER stress in yeast. The protein Nvj2p is required for this tethering, which promotes nonvesicular ceramide transport from the ER to the Golgi to alleviate ceramide toxicity. Ceramides are key intermediates in sphingolipid biosynthesis and potent signaling molecules. However, excess ceramide is toxic, causing growth arrest and apoptosis. In this study, we identify a novel mechanism by which cells prevent the toxic accumulation of ceramides; they facilitate nonvesicular ceramide transfer from the endoplasmic reticulum (ER) to the Golgi complex, where ceramides are converted to complex sphingolipids. We find that the yeast protein Nvj2p promotes the nonvesicular transfer of ceramides from the ER to the Golgi complex. The protein is a tether that generates close contacts between these compartments and may directly transport ceramide. Nvj2p normally resides at contacts between the ER and other organelles, but during ER stress, it relocalizes to and increases ER–Golgi contacts. ER–Golgi contacts fail to form during ER stress in cells lacking Nvj2p. Our findings demonstrate that cells regulate ER–Golgi contacts in response to stress and reveal that nonvesicular ceramide transfer out of the ER prevents the buildup of toxic amounts of ceramides.
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Affiliation(s)
- Li-Ka Liu
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Vineet Choudhary
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Alexandre Toulmay
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - William A Prinz
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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14
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Filipuzzi I, Cotesta S, Perruccio F, Knapp B, Fu Y, Studer C, Pries V, Riedl R, Helliwell SB, Petrovic KT, Movva NR, Sanglard D, Tao J, Hoepfner D. High-Resolution Genetics Identifies the Lipid Transfer Protein Sec14p as Target for Antifungal Ergolines. PLoS Genet 2016; 12:e1006374. [PMID: 27855158 PMCID: PMC5147771 DOI: 10.1371/journal.pgen.1006374] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/20/2016] [Indexed: 12/25/2022] Open
Abstract
Invasive infections by fungal pathogens cause more deaths than malaria worldwide. We found the ergoline compound NGx04 in an antifungal screen, with selectivity over mammalian cells. High-resolution chemogenomics identified the lipid transfer protein Sec14p as the target of NGx04 and compound-resistant mutations in Sec14p define compound-target interactions in the substrate binding pocket of the protein. Beyond its essential lipid transfer function in a variety of pathogenic fungi, Sec14p is also involved in secretion of virulence determinants essential for the pathogenicity of fungi such as Cryptococcus neoformans, making Sec14p an attractive antifungal target. Consistent with this dual function, we demonstrate that NGx04 inhibits the growth of two clinical isolates of C. neoformans and that NGx04-related compounds have equal and even higher potency against C. neoformans. Furthermore NGx04 analogues showed fungicidal activity against a fluconazole resistant C. neoformans strain. In summary, we present genetic evidence that NGx04 inhibits fungal Sec14p and initial data supporting NGx04 as a novel antifungal starting point. Emerging resistance to antibiotics led to an inglorious revival of infectious diseases. Furthermore, in the past 30 years, only one novel anti-fungal target has been discovered which was used to develop therapies against. Therefore pathogen-selective targets and knowledge about possible resistance determinants are of utmost importance to successfully develop new medicines. Here we describe the identification of anti-fungal ergolines, targeting the lipid transfer protein Sec14p, and inhibiting the growth of two clinical isolates of the pathogenic fungus Cryptococcus neoformans. Both, compound and target represent attractive points for further investigations: Sec14p as it differs significantly from the human homolog and as it has been implicated in fungal viability and pathogenicity, and, ergolines as they are used in the clinic against a variety of diseases demonstrating both efficacy and safety.
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Affiliation(s)
- Ireos Filipuzzi
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
- * E-mail:
| | - Simona Cotesta
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Francesca Perruccio
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Britta Knapp
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Yue Fu
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Christian Studer
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Verena Pries
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Ralph Riedl
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Stephen B. Helliwell
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Katarina T. Petrovic
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - N. Rao Movva
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne and University Hospital Center, Lausanne, Switzerland
| | - Jianshi Tao
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Dominic Hoepfner
- Novartis Institutes for BioMedical Research, Novartis Campus, Basel, Switzerland
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15
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Frades I, Andreasson E. Phytophthora infestans specific phosphorylation patterns and new putative control targets. Fungal Biol 2016; 120:631-644. [PMID: 27020162 DOI: 10.1016/j.funbio.2016.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/16/2015] [Accepted: 01/06/2016] [Indexed: 11/15/2022]
Abstract
In this study we applied biomathematical searches of gene regulatory mechanisms to learn more about oomycete biology and to identify new putative targets for pesticides or biological control against Phytophthora infestans. First, oomycete phylum-specific phosphorylation motifs were found by discriminative n-gram analysis. We found 11.600 P. infestans specific n-grams, mapping 642 phosphoproteins. The most abundant group among these related to phosphatidylinositol metabolism. Due to the large number of possible targets found and our hypothesis that multi-level control is a sign of usefulness as targets for intervention, we identified overlapping targets with a second screen. This was performed to identify proteins dually regulated by small RNA and phosphorylation. We found 164 proteins to be regulated by both sRNA and phosphorylation and the dominating functions where phosphatidylinositol signalling/metabolism, endocytosis, and autophagy. Furthermore we performed a similar regulatory study and discriminative n-gram analysis of proteins with no clear orthologs in other species and proteins that are known to be unique to P. infestans such as the RxLR effectors, Crinkler (CRN) proteins and elicitins. We identified CRN proteins with specific phospho-motifs present in all life stages. PITG_12626, PITG_14042 and PITG_23175 are CRN proteins that have species-specific phosphorylation motifs and are subject to dual regulation.
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Affiliation(s)
- Itziar Frades
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, SE-230 53, Sweden.
| | - Erik Andreasson
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, SE-230 53, Sweden
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16
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Khan D, McGrath KR, Dorosheva O, Bankaitis VA, Tripathi A. Structural elements that govern Sec14-like PITP sensitivities to potent small molecule inhibitors. J Lipid Res 2016; 57:650-62. [PMID: 26921357 DOI: 10.1194/jlr.m066381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Indexed: 12/15/2022] Open
Abstract
Sec14-like phosphatidylinositol transfer proteins (PITPs) play important biological functions in integrating multiple aspects of intracellular lipid metabolism with phosphatidylinositol-4-phosphate signaling. As such, these proteins offer new opportunities for highly selective chemical interference with specific phosphoinositide pathways in cells. The first and best characterized small molecule inhibitors of the yeast PITP, Sec14, are nitrophenyl(4-(2-methoxyphenyl)piperazin-1-yl)methanones (NPPMs), and a hallmark feature of NPPMs is their exquisite targeting specificities for Sec14 relative to other closely related Sec14-like PITPs. Our present understanding of Sec14::NPPM binding interactions is based on computational docking and rational loss-of-function approaches. While those approaches have been informative, we still lack an adequate understanding of the basis for the high selectivity of NPPMs among closely related Sec14-like PITPs. Herein, we describe a Sec14 motif, which we term the VV signature, that contributes significantly to the NPPM sensitivity/resistance of Sec14-like phosphatidylinositol (PtdIns)/phosphatidylcholine (PtdCho) transfer proteins. The data not only reveal previously unappreciated determinants that govern Sec14-like PITP sensitivities to NPPMs, but enable predictions of which Sec14-like PtdIns/PtdCho transfer proteins are likely to be NPPM resistant or sensitive based on primary sequence considerations. Finally, the data provide independent evidence in support of previous studies highlighting the importance of Sec14 residue Ser173 in the mechanism by which NPPMs engage and inhibit Sec14-like PITPs.
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Affiliation(s)
- Danish Khan
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Kaitlyn R McGrath
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Oleksandra Dorosheva
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128
| | - Vytas A Bankaitis
- Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128 Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 Chemistry, Texas A&M University, College Station, TX 77843-2128
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114
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17
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Johansen J, Ramanathan V, Beh CT. Vesicle trafficking from a lipid perspective: Lipid regulation of exocytosis in Saccharomyces cerevisiae. CELLULAR LOGISTICS 2014. [PMID: 23181198 PMCID: PMC3498074 DOI: 10.4161/cl.20490] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The protein cargo transported by specific types of vesicles largely defines the different secretory trafficking pathways operating within cells. However, mole per mole the most abundant cargo contained within transport vesicles is not protein, but lipid. Taking a "lipid-centric" point-of-view, we examine the importance of lipid signaling, membrane lipid organization and lipid metabolism for vesicle transport during exocytosis in budding yeast. In fact, the essential requirement for some exocytosis regulatory proteins can be bypassed by making simple manipulations of the lipids involved. During polarized exocytosis the sequential steps required to generate post-Golgi vesicles and target them to the plasma membrane (PM) involves the interplay of several types of lipids that are coordinately linked through PI4P metabolism and signaling. In turn, PI4P levels are regulated by PI4P kinases, the Sac1p PI4P phosphatase and the yeast Osh proteins, which are homologs of mammalian oxysterol-binding protein (OSBP). Together these regulators integrate the transitional steps required for vesicle maturation directly through changes in lipid composition and organization.
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Affiliation(s)
- Jesper Johansen
- Department of Molecular Biology and Biochemistry; Simon Fraser University; Burnaby, BC Canada
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18
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Ren J, Pei-Chen Lin C, Pathak MC, Temple BRS, Nile AH, Mousley CJ, Duncan MC, Eckert DM, Leiker TJ, Ivanova PT, Myers DS, Murphy RC, Brown HA, Verdaasdonk J, Bloom KS, Ortlund EA, Neiman AM, Bankaitis VA. A phosphatidylinositol transfer protein integrates phosphoinositide signaling with lipid droplet metabolism to regulate a developmental program of nutrient stress-induced membrane biogenesis. Mol Biol Cell 2014; 25:712-27. [PMID: 24403601 PMCID: PMC3937096 DOI: 10.1091/mbc.e13-11-0634] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/10/2013] [Accepted: 12/23/2013] [Indexed: 12/31/2022] Open
Abstract
Lipid droplet (LD) utilization is an important cellular activity that regulates energy balance and release of lipid second messengers. Because fatty acids exhibit both beneficial and toxic properties, their release from LDs must be controlled. Here we demonstrate that yeast Sfh3, an unusual Sec14-like phosphatidylinositol transfer protein, is an LD-associated protein that inhibits lipid mobilization from these particles. We further document a complex biochemical diversification of LDs during sporulation in which Sfh3 and select other LD proteins redistribute into discrete LD subpopulations. The data show that Sfh3 modulates the efficiency with which a neutral lipid hydrolase-rich LD subclass is consumed during biogenesis of specialized membrane envelopes that package replicated haploid meiotic genomes. These results present novel insights into the interface between phosphoinositide signaling and developmental regulation of LD metabolism and unveil meiosis-specific aspects of Sfh3 (and phosphoinositide) biology that are invisible to contemporary haploid-centric cell biological, proteomic, and functional genomics approaches.
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Affiliation(s)
- Jihui Ren
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
| | - Coney Pei-Chen Lin
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Manish C. Pathak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-4250
| | - Brenda R. S. Temple
- R. L. Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7260
| | - Aaron H. Nile
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
| | - Carl J. Mousley
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
| | - Mara C. Duncan
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Debra M. Eckert
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650
| | - Thomas J. Leiker
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80045-0511
| | - Pavlina T. Ivanova
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600
| | - David S. Myers
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600
| | - Robert C. Murphy
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80045-0511
| | - H. Alex Brown
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600
| | - Jolien Verdaasdonk
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Kerry S. Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Eric A. Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-4250
| | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Vytas A. Bankaitis
- Department of Molecular and Cellular Medicine, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-1114
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19
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The response to inositol: regulation of glycerolipid metabolism and stress response signaling in yeast. Chem Phys Lipids 2014; 180:23-43. [PMID: 24418527 DOI: 10.1016/j.chemphyslip.2013.12.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 12/26/2013] [Indexed: 12/13/2022]
Abstract
This article focuses on discoveries of the mechanisms governing the regulation of glycerolipid metabolism and stress response signaling in response to the phospholipid precursor, inositol. The regulation of glycerolipid lipid metabolism in yeast in response to inositol is highly complex, but increasingly well understood, and the roles of individual lipids in stress response are also increasingly well characterized. Discoveries that have emerged over several decades of genetic, molecular and biochemical analyses of metabolic, regulatory and signaling responses of yeast cells, both mutant and wild type, to the availability of the phospholipid precursor, inositol are discussed.
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20
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Nile AH, Tripathi A, Yuan P, Mousley CJ, Suresh S, Wallace IM, Shah SD, Pohlhaus DT, Temple B, Nislow C, Giaever G, Tropsha A, Davis RW, St Onge RP, Bankaitis VA. PITPs as targets for selectively interfering with phosphoinositide signaling in cells. Nat Chem Biol 2014; 10:76-84. [PMID: 24292071 PMCID: PMC4059020 DOI: 10.1038/nchembio.1389] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 10/02/2013] [Indexed: 01/26/2023]
Abstract
Sec14-like phosphatidylinositol transfer proteins (PITPs) integrate diverse territories of intracellular lipid metabolism with stimulated phosphatidylinositol-4-phosphate production and are discriminating portals for interrogating phosphoinositide signaling. Yet, neither Sec14-like PITPs nor PITPs in general have been exploited as targets for chemical inhibition for such purposes. Herein, we validate what is to our knowledge the first small-molecule inhibitors (SMIs) of the yeast PITP Sec14. These SMIs are nitrophenyl(4-(2-methoxyphenyl)piperazin-1-yl)methanones (NPPMs) and are effective inhibitors in vitro and in vivo. We further establish that Sec14 is the sole essential NPPM target in yeast and that NPPMs exhibit exquisite targeting specificities for Sec14 (relative to related Sec14-like PITPs), propose a mechanism for how NPPMs exert their inhibitory effects and demonstrate that NPPMs exhibit exquisite pathway selectivity in inhibiting phosphoinositide signaling in cells. These data deliver proof of concept that PITP-directed SMIs offer new and generally applicable avenues for intervening with phosphoinositide signaling pathways with selectivities superior to those afforded by contemporary lipid kinase-directed strategies.
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Affiliation(s)
- Aaron H. Nile
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090 USA
| | - Ashutosh Tripathi
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
- Laboratory for Molecular Modeling, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7355 USA
| | - Peihua Yuan
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
| | - Carl J. Mousley
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
| | - Sundari Suresh
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Iain Michael Wallace
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Sweety D. Shah
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090 USA
| | - Denise Teotico Pohlhaus
- Laboratory for Molecular Modeling, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7355 USA
| | - Brenda Temple
- R. L. Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260 USA
| | - Corey Nislow
- Faculty of Pharmaceutical Sciences,, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Guri Giaever
- Faculty of Pharmaceutical Sciences,, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Alexander Tropsha
- Laboratory for Molecular Modeling, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7355 USA
| | - Ronald W. Davis
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Robert P. St Onge
- Department of Biochemistry, Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304
| | - Vytas A. Bankaitis
- Department of Molecular & Cellular Medicine, Department of Biochemistry & Biophysics, Department of Chemistry, Texas A&M University, College Station, Texas 77843-1114 USA
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090 USA
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21
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Mysyakina IS, Sergeeva YE, Sorokin VV, Ivashechkin AA, Kostrikina NA, Feofilova EP. Lipid and elemental composition as indicators of the physiological state of sporangiospores in Mucor hiemalis cultures of different ages. Microbiology (Reading) 2014. [DOI: 10.1134/s0026261714020155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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22
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Fernández-Murray JP, Ngo MH, McMaster CR. Choline transport activity regulates phosphatidylcholine synthesis through choline transporter Hnm1 stability. J Biol Chem 2013; 288:36106-15. [PMID: 24187140 DOI: 10.1074/jbc.m113.499855] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [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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23
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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24
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Park M, Do E, Jung WH. Lipolytic enzymes involved in the virulence of human pathogenic fungi. MYCOBIOLOGY 2013; 41:67-72. [PMID: 23874127 PMCID: PMC3714442 DOI: 10.5941/myco.2013.41.2.67] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 06/08/2013] [Indexed: 06/02/2023]
Abstract
Pathogenic microbes secrete various enzymes with lipolytic activities to facilitate their survival within the host. Lipolytic enzymes include extracellular lipases and phospholipases, and several lines of evidence have suggested that these enzymes contribute to the virulence of pathogenic fungi. Candida albicans and Cryptococcus neoformans are the most commonly isolated human fungal pathogens, and several biochemical and molecular approaches have identified their extracellular lipolytic enzymes. The role of lipases and phospholipases in the virulence of C. albicans has been extensively studied, and these enzymes have been shown to contribute to C. albicans morphological transition, colonization, cytotoxicity, and penetration to the host. While not much is known about the lipases in C. neoformans, the roles of phospholipases in the dissemination of fungal cells in the host and in signaling pathways have been described. Lipolytic enzymes may also influence the survival of the lipophilic cutaneous pathogenic yeast Malassezia species within the host, and an unusually high number of lipase-coding genes may complement the lipid dependency of this fungus. This review briefly describes the current understanding of the lipolytic enzymes in major human fungal pathogens, namely C. albicans, C. neoformans, and Malassezia spp.
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Affiliation(s)
- Minji Park
- Department of Systems Biotechnology, Chung-Ang University, Anseong 456-756, Korea
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25
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Curwin AJ, LeBlanc MA, Fairn GD, McMaster CR. Localization of lipid raft proteins to the plasma membrane is a major function of the phospholipid transfer protein Sec14. PLoS One 2013; 8:e55388. [PMID: 23383173 PMCID: PMC3559501 DOI: 10.1371/journal.pone.0055388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/28/2012] [Indexed: 11/30/2022] Open
Abstract
The Sec14 protein domain is a conserved tertiary structure that binds hydrophobic ligands. The Sec14 protein from Saccharomyces cerevisiae is essential with studies of S. cerevisiae Sec14 cellular function facilitated by a sole temperature sensitive allele, sec14ts. The sec14ts allele encodes a protein with a point mutation resulting in a single amino acid change, Sec14G266D. In this study results from a genome-wide genetic screen, and pharmacological data, provide evidence that the Sec14G266D protein is present at a reduced level compared to wild type Sec14 due to its being targeted to the proteosome. Increased expression of the sec14ts allele ameliorated growth arrest, but did not restore the defects in membrane accumulation or vesicular transport known to be defective in sec14ts cells. We determined that trafficking and localization of two well characterized lipid raft resident proteins, Pma1 and Fus-Mid-GFP, were aberrant in sec14ts cells. Localization of both lipid raft proteins was restored upon increased expression of the sec14ts allele. We suggest that a major function provided by Sec14 is trafficking and localization of lipid raft proteins.
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Affiliation(s)
- Amy J. Curwin
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Marissa A. LeBlanc
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Gregory D. Fairn
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
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26
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Abstract
The striking morphology of the Golgi complex has fascinated cell biologists since its discovery over 100 years ago. Yet, despite intense efforts to understand how membrane flow relates to Golgi form and function, this organelle continues to baffle cell biologists and biochemists alike. Fundamental questions regarding Golgi function, while hotly debated, remain unresolved. Historically, Golgi function has been described from a protein-centric point of view, but we now appreciate that conceptual frameworks for how lipid metabolism is integrated with Golgi biogenesis and function are essential for a mechanistic understanding of this fascinating organelle. It is from a lipid-centric perspective that we discuss the larger question of Golgi dynamics and membrane trafficking. We review the growing body of evidence for how lipid metabolism is integrally written into the engineering of the Golgi system and highlight questions for future study.
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Affiliation(s)
- Vytas A Bankaitis
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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27
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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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28
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Devising Powerful Genetics, Biochemical and Structural Tools in the Functional Analysis of Phosphatidylinositol Transfer Proteins (PITPs) Across Diverse Species. Methods Cell Biol 2012; 108:249-302. [DOI: 10.1016/b978-0-12-386487-1.00013-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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29
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Mousley CJ, Davison JM, Bankaitis VA. Sec14 like PITPs couple lipid metabolism with phosphoinositide synthesis to regulate Golgi functionality. Subcell Biochem 2012; 59:271-87. [PMID: 22374094 DOI: 10.1007/978-94-007-3015-1_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An interface coordinating lipid metabolism with proteins that regulate membrane trafficking is necessary to regulate Golgi morphology and dynamics. Such an interface facilitates the membrane deformations required for vesicularization, forms platforms for protein recruitment and assembly on appropriate sites on a membrane surface and provides lipid co-factors for optimal protein activity in the proper spatio-temporally regulated manner. Importantly, Sec14 and Sec14-like proteins are a unique superfamily of proteins that sense specific aspects of lipid metabolism, employing this information to potentiate phosphoinositide production. Therefore, Sec14 and Sec14 like proteins form central conduits to integrate multiple aspects of lipid metabolism with productive phosphoinositide signaling.
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Affiliation(s)
- Carl J Mousley
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 27599-7090, Chapel Hill, NC, USA,
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30
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Selvy PE, Lavieri RR, Lindsley CW, Brown HA. Phospholipase D: enzymology, functionality, and chemical modulation. Chem Rev 2011; 111:6064-119. [PMID: 21936578 PMCID: PMC3233269 DOI: 10.1021/cr200296t] [Citation(s) in RCA: 269] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Paige E Selvy
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37064, USA
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31
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Abstract
The yeast Saccharomyces cerevisiae, with its full complement of organelles, synthesizes membrane phospholipids by pathways that are generally common to those found in higher eukaryotes. Phospholipid synthesis in yeast is regulated in response to a variety of growth conditions (e.g., inositol supplementation, zinc depletion, and growth stage) by a coordination of genetic (e.g., transcriptional activation and repression) and biochemical (e.g., activity modulation and localization) mechanisms. Phosphatidate (PA), whose cellular levels are controlled by the activities of key phospholipid synthesis enzymes, plays a central role in the transcriptional regulation of phospholipid synthesis genes. In addition to the regulation of gene expression, phosphorylation of key phospholipid synthesis catalytic and regulatory proteins controls the metabolism of phospholipid precursors and products.
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Affiliation(s)
- George M Carman
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901, USA.
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32
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Ren J, Schaaf G, Bankaitis VA, Ortlund EA, Pathak MC. Crystallization and preliminary X-ray diffraction analysis of Sfh3, a member of the Sec14 protein superfamily. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1239-43. [PMID: 22102037 PMCID: PMC3212372 DOI: 10.1107/s1744309111027096] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 07/06/2011] [Indexed: 11/10/2022]
Abstract
Sec14 is the major phosphatidylinositol (PtdIns)/phosphatidylcholine (PtdCho) transfer protein in the yeast Saccharomyces cerevisiae and is the founding member of the Sec14 protein superfamily. Recent functional data suggest that Sec14 functions as a nanoreactor for PtdCho-regulated presentation of PtdIns to PtdIns kinase to affect membrane trafficking. Extrapolation of this concept to other members of the Sec14 superfamily suggests a mechanism by which a comprehensive cohort of Sec14-like nanoreactors sense correspondingly diverse pools of lipid metabolites. In turn, metabolic information is translated to signaling circuits driven by phosphoinositide metabolism. Sfh3, one of five Sec14 homologs in yeast, exhibits several interesting functional features, including its unique localization to lipid particles and microsomes. This localization forecasts novel regulatory interfaces between neutral lipid metabolism and phosphoinositide signaling. To launch a detailed structural and functional characterization of Sfh3, the recombinant protein was purified to homogeneity, diffraction-quality crystals were produced and a native X-ray data set was collected to 2.2 Å resolution. To aid in phasing, SAD X-ray diffraction data were collected to 1.93 Å resolution from an SeMet-labeled crystal at the Southeast Regional Collaborative Access Team at the Advanced Photon Source. Here, the cloning and purification of Sfh3 and the preliminary diffraction of Sfh3 crystals are reported, enabling structural analyses that are expected to reveal novel principles governing ligand binding and functional specificity for Sec14-superfamily proteins.
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Affiliation(s)
- Jihui Ren
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Gabriel Schaaf
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Vytas A. Bankaitis
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Eric A. Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Manish C. Pathak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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Ghosh R, Bankaitis VA. Phosphatidylinositol transfer proteins: negotiating the regulatory interface between lipid metabolism and lipid signaling in diverse cellular processes. Biofactors 2011; 37:290-308. [PMID: 21915936 DOI: 10.1002/biof.180] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphoinositides represent only a small percentage of the total cellular lipid pool. Yet, these molecules play crucial roles in diverse intracellular processes such as signal transduction at membrane-cytosol interface, regulation of membrane trafficking, cytoskeleton organization, nuclear events, and the permeability and transport functions of the membrane. A central principle in such lipid-mediated signaling is the appropriate coordination of these events. Such an intricate coordination demands fine spatial and temporal control of lipid metabolism and organization, and consistent mechanisms for specifically coupling these parameters to dedicated physiological processes. In that regard, recent studies have identified Sec14-like phosphatidylcholine transfer protein (PITPs) as "coincidence detectors," which spatially and temporally link the diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. The integral role of PITPs in eukaryotic signal transduction design is amply demonstrated by the mammalian diseases associated with the derangements in the function of these proteins, to stress response and developmental regulation in plants, to fungal dimorphism and pathogenicity, to membrane trafficking in yeast, and higher eukaryotes. This review updates the recent advances made in the understanding of how these proteins, specifically PITPs of the Sec14-protein superfamily, operate at the molecular level and further describes how this knowledge has advanced our perception on the diverse biological functions of PITPs.
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Affiliation(s)
- Ratna Ghosh
- Lineberger Comprehensive Cancer Center, Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27526-7090, USA.
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34
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Mysyakina IS, Feofilova EP. The role of lipids in the morphogenetic processes of mycelial fungi. Microbiology (Reading) 2011. [DOI: 10.1134/s0026261711030155] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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35
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Schaaf G, Dynowski M, Mousley CJ, Shah SD, Yuan P, Winklbauer EM, de Campos MKF, Trettin K, Quinones MC, Smirnova TI, Yanagisawa LL, Ortlund EA, Bankaitis VA. Resurrection of a functional phosphatidylinositol transfer protein from a pseudo-Sec14 scaffold by directed evolution. Mol Biol Cell 2011; 22:892-905. [PMID: 21248202 PMCID: PMC3057712 DOI: 10.1091/mbc.e10-11-0903] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Sec14-superfamily proteins integrate the lipid metabolome with phosphoinositide synthesis and signaling via primed presentation of phosphatidylinositol (PtdIns) to PtdIns kinases. Sec14 action as a PtdIns-presentation scaffold requires heterotypic exchange of phosphatidylcholine (PtdCho) for PtdIns, or vice versa, in a poorly understood progression of regulated conformational transitions. We identify mutations that confer Sec14-like activities to a functionally inert pseudo-Sec14 (Sfh1), which seemingly conserves all of the structural requirements for Sec14 function. Unexpectedly, the "activation" phenotype results from alteration of residues conserved between Sfh1 and Sec14. Using biochemical and biophysical, structural, and computational approaches, we find the activation mechanism reconfigures atomic interactions between amino acid side chains and internal water in an unusual hydrophilic microenvironment within the hydrophobic Sfh1 ligand-binding cavity. These altered dynamics reconstitute a functional "gating module" that propagates conformational energy from within the hydrophobic pocket to the helical unit that gates pocket access. The net effect is enhanced rates of phospholipid-cycling into and out of the Sfh1* hydrophobic pocket. Taken together, the directed evolution approach reveals an unexpectedly flexible functional engineering of a Sec14-like PtdIns transfer protein-an engineering invisible to standard bioinformatic, crystallographic, and rational mutagenesis approaches.
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Affiliation(s)
- Gabriel Schaaf
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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36
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Soper JH, Kehm V, Burd CG, Bankaitis VA, Lee VMY. Aggregation of α-synuclein in S. cerevisiae is associated with defects in endosomal trafficking and phospholipid biosynthesis. J Mol Neurosci 2010; 43:391-405. [PMID: 20890676 DOI: 10.1007/s12031-010-9455-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 09/17/2010] [Indexed: 01/08/2023]
Abstract
Parkinson's disease is the most common neurodegenerative movement disorder. α-Synuclein is a small synaptic protein that has been linked to familial Parkinson's disease (PD) and is also the primary component of Lewy bodies, the hallmark neuropathology found in the brain of sporadic and familial PD patients. The function of α-synuclein is currently unknown, although it has been implicated in the regulation of synaptic vesicle localization or fusion. Recently, overexpression of α-synuclein was shown to cause cytoplasmic vesicle accumulation in a yeast model of α-synuclein toxicity, but the exact role α-synuclein played in mediating this vesicle aggregation is unclear. Here, we show that α-synuclein induces aggregation of many yeast Rab GTPase proteins, that α-synuclein aggregation is enhanced in yeast mutants that produce high levels of acidic phospholipids, and that α-synuclein colocalizes with yeast membranes that are enriched for phosphatidic acid. Significantly, we demonstrate that α-synuclein expression induces vulnerability to perturbations of Ypt6 and other proteins involved in retrograde endosome-Golgi transport, linking a specific trafficking defect to α-synuclein phospholipid binding. These data suggest new pathogenic mechanisms for α-synuclein neurotoxicity.
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Affiliation(s)
- James H Soper
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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37
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LeBlanc MA, McMaster CR. Surprising roles for phospholipid binding proteins revealed by high throughput geneticsThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process. Biochem Cell Biol 2010; 88:565-74. [DOI: 10.1139/o09-171] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Saccharomyces cerevisiae remains an ideal organism for studying the cell biological roles of lipids in vivo, as yeast has phospholipid metabolic pathways similar to mammalian cells, is easy and economical to manipulate, and is genetically tractable. The availability of isogenic strains containing specific genetic inactivation of each non-essential gene allowed for the development of a high-throughput method, called synthetic genetic analysis (SGA), to identify and describe precise pathways or functions associated with specific genes. This review describes the use of SGA to aid in elucidating the function of two lipid-binding proteins that regulate vesicular transport, Sec14 and Kes1. Sec14 was first identified as a phosphatidylcholine (PC) – phosphatidylinositol (PI) transfer protein required for viability, with reduced Sec14 function resulting in diminished vesicular transport out of the trans-Golgi. Although Sec14 is required for cell viability, inactivating the KES1 gene that encodes for a member of the oxysterol binding protein family in cells lacking Sec14 function results in restoration of vesicular transport and cell growth. SGA analysis identified a role for Kes1 and Sec14 in regulating the level and function of Golgi PI-4-phosphate (PI-4-P). SGA also determined that Sec14 not only regulates vesicular transport out of the trans-Golgi, but also transport from endosomes to the trans-Golgi. Comparing SGA screens in databases, coupled with genetic and cell biological analyses, further determined that the PI-4-P pool affected by Kes1 is generated by the PI 4-kinase Pik1. An important biological role for Sec14 and Kes1 revealed by SGA is coordinate regulation of the Pik1-generated Golgi PI-4-P pool that in turn is essential for vesicular transport into and out of the trans-Golgi.
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Affiliation(s)
- Marissa A. LeBlanc
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS B3H 4H7, Canada
| | - Christopher R. McMaster
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS B3H 4H7, Canada
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Sphingolipid metabolism in trans-golgi/endosomal membranes and the regulation of intracellular homeostatic processes in eukaryotic cells. ACTA ACUST UNITED AC 2010; 50:339-48. [DOI: 10.1016/j.advenzreg.2009.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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39
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Bankaitis VA, Mousley CJ, Schaaf G. The Sec14 superfamily and mechanisms for crosstalk between lipid metabolism and lipid signaling. Trends Biochem Sci 2009; 35:150-60. [PMID: 19926291 DOI: 10.1016/j.tibs.2009.10.008] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 10/26/2009] [Accepted: 10/27/2009] [Indexed: 01/03/2023]
Abstract
Lipid signaling pathways define central mechanisms for cellular regulation. Productive lipid signaling requires an orchestrated coupling between lipid metabolism, lipid organization and the action of protein machines that execute appropriate downstream reactions. Using membrane trafficking control as primary context, we explore the idea that the Sec14-protein superfamily defines a set of modules engineered for the sensing of specific aspects of lipid metabolism and subsequent transduction of 'sensing' information to a phosphoinositide-driven 'execution phase'. In this manner, the Sec14 superfamily connects diverse territories of the lipid metabolome with phosphoinositide signaling in a productive 'crosstalk' between these two systems. Mechanisms of crosstalk, by which non-enzymatic proteins integrate metabolic cues with the action of interfacial enzymes, represent unappreciated regulatory themes in lipid signaling.
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Affiliation(s)
- Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill. Chapel Hill, North Carolina 27599-7090, USA
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40
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Liu Y, Boukhelifa M, Tribble E, Bankaitis VA. Functional studies of the mammalian Sac1 phosphoinositide phosphatase. ACTA ACUST UNITED AC 2009; 49:75-86. [PMID: 19534026 DOI: 10.1016/j.advenzreg.2009.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yang Liu
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
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41
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Phospholipase D function in Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:970-4. [DOI: 10.1016/j.bbalip.2009.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 01/07/2009] [Accepted: 01/08/2009] [Indexed: 11/21/2022]
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42
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Raghu P, Coessens E, Manifava M, Georgiev P, Pettitt T, Wood E, Garcia-Murillas I, Okkenhaug H, Trivedi D, Zhang Q, Razzaq A, Zaid O, Wakelam M, O'Kane CJ, Ktistakis N. Rhabdomere biogenesis in Drosophila photoreceptors is acutely sensitive to phosphatidic acid levels. ACTA ACUST UNITED AC 2009; 185:129-45. [PMID: 19349583 PMCID: PMC2700502 DOI: 10.1083/jcb.200807027] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphatidic acid (PA) is postulated to have both structural and signaling functions during membrane dynamics in animal cells. In this study, we show that before a critical time period during rhabdomere biogenesis in Drosophila melanogaster photoreceptors, elevated levels of PA disrupt membrane transport to the apical domain. Lipidomic analysis shows that this effect is associated with an increase in the abundance of a single, relatively minor molecular species of PA. These transport defects are dependent on the activation state of Arf1. Transport defects via PA generated by phospholipase D require the activity of type I phosphatidylinositol (PI) 4 phosphate 5 kinase, are phenocopied by knockdown of PI 4 kinase, and are associated with normal endoplasmic reticulum to Golgi transport. We propose that PA levels are critical for apical membrane transport events required for rhabdomere biogenesis.
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Affiliation(s)
- Padinjat Raghu
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Cambridge, England, UK.
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43
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Riebeling C, Morris AJ, Shields D. Phospholipase D in the Golgi apparatus. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:876-80. [PMID: 19376267 DOI: 10.1016/j.bbalip.2009.04.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 04/06/2009] [Accepted: 04/09/2009] [Indexed: 12/18/2022]
Abstract
Phospholipase D has long been implicated in vesicle formation and vesicular transport through the secretory pathway. The Golgi apparatus has been shown to exhibit a plethora of mechanisms of vesicle formation at different stages to accommodate a wide variety of cargo. Phospholipase D has been found on the Golgi apparatus and is regulated by ADP-ribosylation factors which are themselves regulators of vesicle trafficking. Moreover, the product of phospholipase D activity, phosphatidic acid, as well as its degradation product diacylglycerol, have been implicated in vesicle fission and fusion events. Here we summarize recent advances in the understanding of the role of phospholipase D at the Golgi apparatus.
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Affiliation(s)
- Christian Riebeling
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461, USA.
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44
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Emerging findings from studies of phospholipase D in model organisms (and a short update on phosphatidic acid effectors). Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:889-97. [PMID: 19345277 DOI: 10.1016/j.bbalip.2009.03.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 03/19/2009] [Accepted: 03/24/2009] [Indexed: 02/05/2023]
Abstract
Phospholipase D (PLD) catalyses the hydrolysis of phosphatidylcholine to generate phosphatidic acid and choline. Historically, much PLD work has been conducted in mammalian settings although genes encoding enzymes of this family have been identified in all eukaryotic organisms. Recently, important insights on PLD function are emerging from work in yeast, but much less is known about PLD in other organisms. In this review we will summarize what is known about phospholipase D in several model organisms, including C. elegans, D. discoideum, D. rerio and D. melanogaster. In the cases where knockouts are available (C. elegans, Dictyostelium and Drosophila) the PLD gene(s) appear not to be essential for viability, but several studies are beginning to identify pathways where this activity has a role. Given that the proteins in model organisms are very similar to their mammalian counterparts, we expect that future studies in model organisms will complement and extend ongoing work in mammalian settings. At the end of this review we will also provide a short update on phosphatidic acid targets, a topic last reviewed in 2006.
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Curwin AJ, Fairn GD, McMaster CR. Phospholipid transfer protein Sec14 is required for trafficking from endosomes and regulates distinct trans-Golgi export pathways. J Biol Chem 2009; 284:7364-75. [PMID: 19129178 DOI: 10.1074/jbc.m808732200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A protein known to regulate both lipid metabolism and vesicular transport is the phosphatidylcholine/phosphatidylinositol transfer protein Sec14 of Saccharomyces cerevisiae. Sec14 is thought to globally affect secretion from the trans-Golgi. The results from a synthetic genetic array screen for genes whose inactivation impaired growth of cells with a temperature-sensitive SEC14 allele implied Sec14 regulates transport into and out of the Golgi. This prompted us to examine the role of Sec14 in various vesicular transport pathways. We determined that Sec14 function was required for the route followed by Bgl2, whereas trafficking of other secreted proteins, including Hsp150, Cts1, Scw4, Scw10, Exg1, Cis3, and Ygp1, still occurred, indicating Sec14 regulates specific trans-Golgi export pathways. Upon diminution of Sec14 function, the v-SNARE Snc1 accumulated in endosomes and the trans-Golgi. Its accumulation in endosomes is consistent with Sec14 being required for transport from endosomes to the trans-Golgi. Sec14 was also required for trafficking of Ste3 and the lipophilic dye FM4-64 from the plasma membrane to the vacuole at the level of the endosome. The combined genetic and cell biology data are consistent with regulation of endosome trafficking being a major role for Sec14. We further determined that lipid ligand occupancy differentially regulates Sec14 functions.
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Affiliation(s)
- Amy J Curwin
- Department of Pediatrics, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
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46
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Abstract
Phospholipid synthesis in the yeast Saccharomyces cerevisiae is a complex process that involves regulation by both genetic and biochemical mechanisms. The activity levels of phospholipid synthesis enzymes are controlled by gene expression (e.g., transcription) and by factors (lipids, water-soluble phospholipid precursors and products, and covalent modification of phosphorylation) that modulate catalysis. Phosphatidic acid, whose levels are controlled by the biochemical regulation of key phospholipid synthesis enzymes, plays a central role in the regulation of phospholipid synthesis gene expression.
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Affiliation(s)
- George M Carman
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA.
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47
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Phillips SE, Vincent P, Rizzieri KE, Schaaf G, Bankaitis VA, Gaucher EA. The Diverse Biological Functions of Phosphatidylinositol Transfer Proteins in Eukaryotes. Crit Rev Biochem Mol Biol 2008; 41:21-49. [PMID: 16455519 DOI: 10.1080/10409230500519573] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Phosphatidylinositol/phosphatidylcholine transfer proteins (PITPs) remain largely functionally uncharacterized, despite the fact that they are highly conserved and are found in all eukaryotic cells thus far examined by biochemical or sequence analysis approaches. The available data indicate a role for PITPs in regulating specific interfaces between lipid-signaling and cellular function. In this regard, a role for PITPs in controlling specific membrane trafficking events is emerging as a common functional theme. However, the mechanisms by which PITPs regulate lipid-signaling and membrane-trafficking functions remain unresolved. Specific PITP dysfunctions are now linked to neurodegenerative and intestinal malabsorption diseases in mammals, to stress response and developmental regulation in higher plants, and to previously uncharacterized pathways for regulating membrane trafficking in yeast and higher eukaryotes, making it clear that PITPs are integral parts of a highly conserved signal transduction strategy in eukaryotes. Herein, we review recent progress in deciphering the biological functions of PITPs, and discuss some of the open questions that remain.
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Affiliation(s)
- Scott E Phillips
- Department of Cell and Developmental Biology, School of Medicine, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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48
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Mousley CJ, Tyeryar K, Ile KE, Schaaf G, Brost RL, Boone C, Guan X, Wenk MR, Bankaitis VA. Trans-Golgi network and endosome dynamics connect ceramide homeostasis with regulation of the unfolded protein response and TOR signaling in yeast. Mol Biol Cell 2008; 19:4785-803. [PMID: 18753406 DOI: 10.1091/mbc.e08-04-0426] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Synthetic genetic array analyses identify powerful genetic interactions between a thermosensitive allele (sec14-1(ts)) of the structural gene for the major yeast phosphatidylinositol transfer protein (SEC14) and a structural gene deletion allele (tlg2Delta) for the Tlg2 target membrane-soluble N-ethylmaleimide-sensitive factor attachment protein receptor. The data further demonstrate Sec14 is required for proper trans-Golgi network (TGN)/endosomal dynamics in yeast. Paradoxically, combinatorial depletion of Sec14 and Tlg2 activities elicits trafficking defects from the endoplasmic reticulum, and these defects are accompanied by compromise of the unfolded protein response (UPR). UPR failure occurs downstream of Hac1 mRNA splicing, and it is further accompanied by defects in TOR signaling. The data link TGN/endosomal dynamics with ceramide homeostasis, UPR activity, and TOR signaling in yeast, and they identify the Sit4 protein phosphatase as a primary conduit through which ceramides link to the UPR. We suggest combinatorial Sec14/Tlg2 dysfunction evokes inappropriate turnover of complex sphingolipids in endosomes. One result of this turnover is potentiation of ceramide-activated phosphatase-mediated down-regulation of the UPR. These results provide new insight into Sec14 function, and they emphasize the TGN/endosomal system as a central hub for homeostatic regulation in eukaryotes.
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Affiliation(s)
- Carl J Mousley
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
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49
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Curwin AJ, McMaster CR. Structure and function of the enigmatic Sec14 domain-containing proteins and the etiology of human disease. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17460875.3.4.399] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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50
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Liu Y, Boukhelifa M, Tribble E, Morin-Kensicki E, Uetrecht A, Bear JE, Bankaitis VA. The Sac1 phosphoinositide phosphatase regulates Golgi membrane morphology and mitotic spindle organization in mammals. Mol Biol Cell 2008; 19:3080-96. [PMID: 18480408 DOI: 10.1091/mbc.e07-12-1290] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Phosphoinositides (PIPs) are ubiquitous regulators of signal transduction events in eukaryotic cells. PIPs are degraded by various enzymes, including PIP phosphatases. The integral membrane Sac1 phosphatases represent a major class of such enzymes. The central role of lipid phosphatases in regulating PIP homeostasis notwithstanding, the biological functions of Sac1-phosphatases remain poorly characterized. Herein, we demonstrate that functional ablation of the single murine Sac1 results in preimplantation lethality in the mouse and that Sac1 insufficiencies result in disorganization of mammalian Golgi membranes and mitotic defects characterized by multiple mechanically active spindles. Complementation experiments demonstrate mutant mammalian Sac1 proteins individually defective in either phosphoinositide phosphatase activity, or in recycling of the enzyme from the Golgi system back to the endoplasmic reticulum, are nonfunctional proteins in vivo. The data indicate Sac1 executes an essential household function in mammals that involves organization of both Golgi membranes and mitotic spindles and that both enzymatic activity and endoplasmic reticulum localization are important Sac1 functional properties.
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Affiliation(s)
- Yang Liu
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
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