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Rizzo R, Russo D, Kurokawa K, Sahu P, Lombardi B, Supino D, Zhukovsky MA, Vocat A, Pothukuchi P, Kunnathully V, Capolupo L, Boncompain G, Vitagliano C, Zito Marino F, Aquino G, Montariello D, Henklein P, Mandrich L, Botti G, Clausen H, Mandel U, Yamaji T, Hanada K, Budillon A, Perez F, Parashuraman S, Hannun YA, Nakano A, Corda D, D'Angelo G, Luini A. Golgi maturation-dependent glycoenzyme recycling controls glycosphingolipid biosynthesis and cell growth via GOLPH3. EMBO J 2021; 40:e107238. [PMID: 33749896 DOI: 10.15252/embj.2020107238] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/24/2021] [Accepted: 02/10/2021] [Indexed: 01/08/2023] Open
Abstract
Glycosphingolipids are important components of the plasma membrane where they modulate the activities of membrane proteins including signalling receptors. Glycosphingolipid synthesis relies on competing reactions catalysed by Golgi-resident enzymes during the passage of substrates through the Golgi cisternae. The glycosphingolipid metabolic output is determined by the position and levels of the enzymes within the Golgi stack, but the mechanisms that coordinate the intra-Golgi localisation of the enzymes are poorly understood. Here, we show that a group of sequentially-acting enzymes operating at the branchpoint among glycosphingolipid synthetic pathways binds the Golgi-localised oncoprotein GOLPH3. GOLPH3 sorts these enzymes into vesicles for intra-Golgi retro-transport, acting as a component of the cisternal maturation mechanism. Through these effects, GOLPH3 controls the sub-Golgi localisation and the lysosomal degradation rate of specific enzymes. Increased GOLPH3 levels, as those observed in tumours, alter glycosphingolipid synthesis and plasma membrane composition thereby promoting mitogenic signalling and cell proliferation. These data have medical implications as they outline a novel oncogenic mechanism of action for GOLPH3 based on glycosphingolipid metabolism.
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Affiliation(s)
- Riccardo Rizzo
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy.,Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Lecce, Italy
| | - Domenico Russo
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Pranoy Sahu
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Bernadette Lombardi
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Domenico Supino
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Mikhail A Zhukovsky
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Anthony Vocat
- École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Prathyush Pothukuchi
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Vidya Kunnathully
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Laura Capolupo
- École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | - Carlo Vitagliano
- Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, Naples, Italy
| | | | - Gabriella Aquino
- Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, Naples, Italy
| | - Daniela Montariello
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Petra Henklein
- Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Berlin, Germany
| | - Luigi Mandrich
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Gerardo Botti
- Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, Naples, Italy
| | - Henrik Clausen
- Faculty of Health Sciences, Centre for Glycomics, Department of Cellular and Molecular Medicine Nørre Alle 20, University of Copenhagen, Copenhagen N, Denmark
| | - Ulla Mandel
- Faculty of Health Sciences, Centre for Glycomics, Department of Cellular and Molecular Medicine Nørre Alle 20, University of Copenhagen, Copenhagen N, Denmark
| | - Toshiyuki Yamaji
- Department of Biochemistry & Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kentaro Hanada
- Department of Biochemistry & Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Alfredo Budillon
- Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, Naples, Italy
| | - Franck Perez
- Institute Curie - CNRS UMR1 44, Research Center, Paris, France
| | | | - Yusuf A Hannun
- Stony Brook University Medical Center, New York, NY, USA
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Daniela Corda
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Giovanni D'Angelo
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy.,École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Protein Amphipathic Helix Insertion: A Mechanism to Induce Membrane Fission. Front Cell Dev Biol 2019; 7:291. [PMID: 31921835 PMCID: PMC6914677 DOI: 10.3389/fcell.2019.00291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 12/19/2022] Open
Abstract
One of the fundamental features of biomembranes is the ability to fuse or to separate. These processes called respectively membrane fusion and fission are central in the homeostasis of events such as those related to intracellular membrane traffic. Proteins that contain amphipathic helices (AHs) were suggested to mediate membrane fission via shallow insertion of these helices into the lipid bilayer. Here we analyze the AH-containing proteins that have been identified as essential for membrane fission and categorize them in few subfamilies, including small GTPases, Atg proteins, and proteins containing either the ENTH/ANTH- or the BAR-domain. AH-containing fission-inducing proteins may require cofactors such as additional proteins (e.g., lipid-modifying enzymes), or lipids (e.g., phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], phosphatidic acid [PA], or cardiolipin). Both PA and cardiolipin possess a cone shape and a negative charge (-2) that favor the recruitment of the AHs of fission-inducing proteins. Instead, PtdIns(4,5)P2 is characterized by an high negative charge able to recruit basic residues of the AHs of fission-inducing proteins. Here we propose that the AHs of fission-inducing proteins contain sequence motifs that bind lipid cofactors; accordingly (K/R/H)(K/R/H)xx(K/R/H) is a PtdIns(4,5)P2-binding motif, (K/R)x6(F/Y) is a cardiolipin-binding motif, whereas KxK is a PA-binding motif. Following our analysis, we show that the AHs of many fission-inducing proteins possess five properties: (a) at least three basic residues on the hydrophilic side, (b) ability to oligomerize, (c) optimal (shallow) depth of insertion into the membrane, (d) positive cooperativity in membrane curvature generation, and (e) specific interaction with one of the lipids mentioned above. These lipid cofactors favor correct conformation, oligomeric state and optimal insertion depth. The most abundant lipid in a given organelle possessing high negative charge (more negative than -1) is usually the lipid cofactor in the fission event. Interestingly, naturally occurring mutations have been reported in AH-containing fission-inducing proteins and related to diseases such as centronuclear myopathy (amphiphysin 2), Charcot-Marie-Tooth disease (GDAP1), Parkinson's disease (α-synuclein). These findings add to the interest of the membrane fission process whose complete understanding will be instrumental for the elucidation of the pathogenesis of diseases involving mutations in the protein AHs.
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Affiliation(s)
- Mikhail A. Zhukovsky
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | | | | | - Daniela Corda
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Phosphatidic acid in membrane rearrangements. FEBS Lett 2019; 593:2428-2451. [PMID: 31365767 DOI: 10.1002/1873-3468.13563] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/16/2022]
Abstract
Phosphatidic acid (PA) is the simplest cellular glycerophospholipid characterized by unique biophysical properties: a small headgroup; negative charge; and a phosphomonoester group. Upon interaction with lysine or arginine, PA charge increases from -1 to -2 and this change stabilizes protein-lipid interactions. The biochemical properties of PA also allow interactions with lipids in several subcellular compartments. Based on this feature, PA is involved in the regulation and amplification of many cellular signalling pathways and functions, as well as in membrane rearrangements. Thereby, PA can influence membrane fusion and fission through four main mechanisms: it is a substrate for enzymes producing lipids (lysophosphatidic acid and diacylglycerol) that are involved in fission or fusion; it contributes to membrane rearrangements by generating negative membrane curvature; it interacts with proteins required for membrane fusion and fission; and it activates enzymes whose products are involved in membrane rearrangements. Here, we discuss the biophysical properties of PA in the context of the above four roles of PA in membrane fusion and fission.
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Affiliation(s)
- Mikhail A Zhukovsky
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Angela Filograna
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Daniela Corda
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. The Structure and Function of Acylglycerophosphate Acyltransferase 4/ Lysophosphatidic Acid Acyltransferase Delta (AGPAT4/LPAATδ). Front Cell Dev Biol 2019; 7:147. [PMID: 31428612 PMCID: PMC6688108 DOI: 10.3389/fcell.2019.00147] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/16/2019] [Indexed: 12/27/2022] Open
Abstract
Lipid-modifying enzymes serve crucial roles in cellular processes such as signal transduction (producing lipid-derived second messengers), intracellular membrane transport (facilitating membrane remodeling needed for membrane fusion/fission), and protein clustering (organizing lipid domains as anchoring platforms). The lipid products crucial in these processes can derive from different metabolic pathways, thus it is essential to know the localization, substrate specificity, deriving products (and their function) of all lipid-modifying enzymes. Here we discuss an emerging family of these enzymes, the lysophosphatidic acid acyltransferases (LPAATs), also known as acylglycerophosphate acyltransferases (AGPATs), that produce phosphatidic acid (PA) having as substrates lysophosphatidic acid (LPA) and acyl-CoA. Eleven LPAAT/AGPAT enzymes have been identified in mice and humans based on sequence homologies, and their localization, specific substrates and functions explored. We focus on one member of the family, LPAATδ, a protein expressed mainly in brain and in muscle (though to a lesser extent in other tissues); while at the cellular level it is localized at the trans-Golgi network membranes and at the mitochondrial outer membranes. LPAATδ is a physiologically essential enzyme since mice knocked-out for Lpaatδ show severe dysfunctions including cognitive impairment, impaired force contractility and altered white adipose tissue. The LPAATδ physiological roles are related to the formation of its product PA. PA is a multifunctional lipid involved in cell signaling as well as in membrane remodeling. In particular, the LPAATδ-catalyzed conversion of LPA (inverted-cone-shaped lipid) to PA (cone-shaped lipid) is considered a mechanism of deformation of the bilayer that favors membrane fission. Indeed, LPAATδ is an essential component of the fission-inducing machinery driven by the protein BARS. In this process, a protein-tripartite complex (BARS/14-3-3γ/phosphoinositide kinase PI4KIIIβ) is recruited at the trans-Golgi network, at the sites where membrane fission is to occur; there, LPAATδ directly interacts with BARS and is activated by BARS. The resulting formation of PA is essential for membrane fission occurring at those spots. Also in mitochondria PA formation has been related to fusion/fission events. Since PA is formed by various enzymatic pathways in different cell compartments, the BARS-LPAATδ interaction indicates the relevance of lipid-modifying enzymes acting exactly where their products are needed (i.e., PA at the Golgi membranes).
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Affiliation(s)
- Mikhail A Zhukovsky
- Institute of Biochemistry and Cell Biology and Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Angela Filograna
- Institute of Biochemistry and Cell Biology and Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology and Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Daniela Corda
- Institute of Biochemistry and Cell Biology and Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Biochemistry and Cell Biology and Institute of Protein Biochemistry, National Research Council, Naples, Italy
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Pagliuso A, Valente C, Giordano LL, Filograna A, Li G, Circolo D, Turacchio G, Marzullo VM, Mandrich L, Zhukovsky MA, Formiggini F, Polishchuk RS, Corda D, Luini A. Golgi membrane fission requires the CtBP1-S/BARS-induced activation of lysophosphatidic acid acyltransferase δ. Nat Commun 2016; 7:12148. [PMID: 27401954 PMCID: PMC4945875 DOI: 10.1038/ncomms12148] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 06/03/2016] [Indexed: 11/25/2022] Open
Abstract
Membrane fission is an essential cellular process by which continuous membranes split into separate parts. We have previously identified CtBP1-S/BARS (BARS) as a key component of a protein complex that is required for fission of several endomembranes, including basolateral post-Golgi transport carriers. Assembly of this complex occurs at the Golgi apparatus, where BARS binds to the phosphoinositide kinase PI4KIIIβ through a 14-3-3γ dimer, as well as to ARF and the PKD and PAK kinases. We now report that, when incorporated into this complex, BARS binds to and activates a trans-Golgi lysophosphatidic acid (LPA) acyltransferase type δ (LPAATδ) that converts LPA into phosphatidic acid (PA); and that this reaction is essential for fission of the carriers. LPA and PA have unique biophysical properties, and their interconversion might facilitate the fission process either directly or indirectly (via recruitment of proteins that bind to PA, including BARS itself).
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Affiliation(s)
- Alessandro Pagliuso
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Carmen Valente
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Lucia Laura Giordano
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Angela Filograna
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Guiling Li
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Diego Circolo
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Gabriele Turacchio
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Vincenzo Manuel Marzullo
- IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare, Via Emanuele Gianturco 113, 80143 Naples, Italy
| | - Luigi Mandrich
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Mikhail A. Zhukovsky
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Fabio Formiggini
- Italian Institute of Technology, Centre for Advanced Biomaterials for Health Care at CRIB, Largo Barsanti e Matteucci 53, Naples 80125, Italy
| | - Roman S. Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Daniela Corda
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
- IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare, Via Emanuele Gianturco 113, 80143 Naples, Italy
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Zhukovsky MA, Lee PH, Ott A, Helms V. Putative cholesterol-binding sites in human immunodeficiency virus (HIV) coreceptors CXCR4 and CCR5. Proteins 2012; 81:555-67. [DOI: 10.1002/prot.24211] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/31/2012] [Accepted: 10/11/2012] [Indexed: 11/08/2022]
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Zhukovsky MA, Basmaciogullari S, Pacheco B, Wang L, Madani N, Haim H, Sodroski J. Thermal stability of the human immunodeficiency virus type 1 (HIV-1) receptors, CD4 and CXCR4, reconstituted in proteoliposomes. PLoS One 2010; 5:e13249. [PMID: 20967243 PMCID: PMC2954141 DOI: 10.1371/journal.pone.0013249] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 09/13/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The entry of human immunodeficiency virus (HIV-1) into host cells involves the interaction of the viral exterior envelope glycoprotein, gp120, and receptors on the target cell. The HIV-1 receptors are CD4 and one of two chemokine receptors, CCR5 or CXCR4. METHODOLOGY/PRINCIPAL FINDINGS We created proteoliposomes that contain CD4, the primary HIV-1 receptor, and one of the coreceptors, CXCR4. Antibodies against CD4 and CXCR4 specifically bound the proteoliposomes. CXCL12, the natural ligand for CXCR4, and the small-molecule CXCR4 antagonist, AMD3100, bound the proteoliposomes with affinities close to those associated with the binding of these molecules to cells expressing CXCR4 and CD4. The HIV-1 gp120 exterior envelope glycoprotein bound tightly to proteoliposomes expressing only CD4 and, in the presence of soluble CD4, bound weakly to proteoliposomes expressing only CXCR4. The thermal stability of CD4 and CXCR4 inserted into liposomes was examined. Thermal denaturation of CXCR4 followed second-order kinetics, with an activation energy (E(a)) of 269 kJ/mol (64.3 kcal/mol) and an inactivation temperature (T(i)) of 56°C. Thermal inactivation of CD4 exhibited a reaction order of 1.3, an E(a) of 278 kJ/mol (66.5 kcal/mol), and a T(i) of 52.2°C. The second-order denaturation kinetics of CXCR4 is unusual among G protein-coupled receptors, and may result from dimeric interactions between CXCR4 molecules. CONCLUSIONS/SIGNIFICANCE Our studies with proteoliposomes containing the native HIV-1 receptors allowed an examination of the binding of biologically important ligands and revealed the higher-order denaturation kinetics of these receptors. CD4/CXCR4-proteoliposomes may be useful for the study of virus-target cell interactions and for the identification of inhibitors.
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Affiliation(s)
- Mikhail A. Zhukovsky
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stéphane Basmaciogullari
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Beatriz Pacheco
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Liping Wang
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Navid Madani
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hillel Haim
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joseph Sodroski
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Division of AIDS, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
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Zhukovsky MA, Markovic I, Bailey AL. Influence of calcium on lipid mixing mediated by influenza hemagglutinin. Arch Biochem Biophys 2007; 465:101-8. [PMID: 17585869 PMCID: PMC2025700 DOI: 10.1016/j.abb.2007.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 04/30/2007] [Accepted: 05/01/2007] [Indexed: 11/22/2022]
Abstract
We studied the influence of calcium on lipid mixing mediated by influenza hemagglutinin (HA). Lipid mixing between HA-expressing cells and liposomes containing disialoganglioside, influenza virus receptor, was studied at 37 degrees C and neutral pH after a low-pH pulse at 4 degrees C. With DSPC/cholesterol liposomes, calcium present after raising the temperature significantly promoted lipid mixing only when it was triggered by a short low-pH application. In case of DOPC/cholesterol liposomes, calcium promotion was observed regardless of the duration of the low-pH pulse. Calcium present during a short, but not long, low-pH application to HA-expressing cells with bound DSPC/cholesterol liposomes at 4 degrees C inhibited subsequent lipid mixing. We hypothesize that calcium influences lipid mixing because it binds to a vestigial esterase domain of hemagglutinin or causes expulsion of the fusion peptide from an electronegative cavity. We suggest that calcium promotes the transition from early and reversible conformation(s) of low pH-activated HA towards an irreversible conformation that underlies both HA-mediated lipid mixing and HA inactivation.
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Affiliation(s)
- Mikhail A Zhukovsky
- Section on Membrane Biology, Laboratory of Cellular and Molecular Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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Zhukovsky MA, Leikina E, Markovic I, Bailey AL, Chernomordik LV. Heterogeneity of early intermediates in cell-liposome fusion mediated by influenza hemagglutinin. Biophys J 2006; 91:3349-58. [PMID: 16905609 PMCID: PMC1614502 DOI: 10.1529/biophysj.106.088005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To explore early intermediates in membrane fusion mediated by influenza virus hemagglutinin (HA) and their dependence on the composition of the target membrane, we studied lipid mixing between HA-expressing cells and liposomes containing phosphatidylcholine (PC) with different hydrocarbon chains. For all tested compositions, our results indicate the existence of at least two types of intermediates, which differ in their lifetimes. The composition of the target membrane affects the stability of fusion intermediates at a stage before lipid mixing. For less fusogenic distearoyl PC-containing liposomes at 4 degrees C, some of the intermediates inactivate, and no intermediates advance to lipid mixing. Fusion intermediates that formed for the more fusogenic dioleoyl PC-containing liposomes did not inactivate and even yielded partial lipid mixing at 4 degrees C. Thus, a more fusogenic target membrane effectively blocks nonproductive release of the conformational energy of HA. Even for the same liposome composition, HA forms two types of fusion intermediates, dissimilar in their stability and propensity to fuse. This diversity of fusion intermediates emphasizes the importance of local membrane composition and local protein concentration in fusion of heterogeneous biological membranes.
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Affiliation(s)
- Mikhail A Zhukovsky
- Laboratory of Cellular and Molecular Biophysics, Section on Membrane Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Sadovnikova NV, Pankov YA, Fedotov VP, Czernushkina AV, Zhukovsky MA, Shcherbacheva LN. The effects of sera obtained from children with insulin-dependent diabetes mellitus on cultivated islet cells: cytotoxicity and insulin release. Exp Clin Endocrinol 1989; 93:166-72. [PMID: 2673810 DOI: 10.1055/s-0029-1210852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Sera were obtained from 24 patients with newly-diagnosed insulin-dependent diabetes mellitus (IDDM) and 14 children with a high risk of diabetes. The influence of the decomplementated sera on basal and stimulated insulin secretion was studied in a mixed culture of newborn rat islet cells. In addition, complement-dependent antibody-mediated cytotoxicity (C'AMC) was measured by 51Cr-release from pre-labelled islet cells. Incubation of the islet cells with sera from ten IDDM patients did not affect the basal insulin release. Sera from other children with IDDM (n = 14) either significantly increased (n = 7) or inhibited (n = 7) basal IRI secretion was compared with the sera of control donors. Nearly half of the sera from the high-risk children was found to be insulin-stimulating. Preincubation of islet cells with sera from IDDM children caused a significant decrease of insulin response to 16.5 mM glucose plus 5 mM theophylline (P less than 0.001). Sera from the high-risk children did influence the response of pancreatic cells to secretagogues. C'AMC was found in 45% of the patients with IDDM and in 33% of the high-risk children, however, there was no correlation between C'AMC and serum effect upon basal insulin secretion. These results suggest the presence of B-cytotropic factors in serum from children with IDDM or with a risk of diabetes. Opposite effects of different sera on insulin secretion may reflect the variety of pathogenetic mechanisms involved in islet cell destruction.
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Affiliation(s)
- N V Sadovnikova
- Institute for Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow
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