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Tallorin L, Villareal VA, Hsia CY, Rodgers MA, Burri DJ, Pfeil MP, Llopis PM, Lindenbach BD, Yang PL. Hepatitis C virus NS3-4A protease regulates the lipid environment for RNA replication by cleaving host enzyme 24-dehydrocholesterol reductase. J Biol Chem 2020; 295:12426-12436. [PMID: 32641492 PMCID: PMC7458815 DOI: 10.1074/jbc.ra120.013455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 03/13/2020] [Revised: 06/29/2020] [Indexed: 12/12/2022] Open
Abstract
Many RNA viruses create specialized membranes for genome replication by manipulating host lipid metabolism and trafficking, but in most cases, we do not know the molecular mechanisms responsible or how specific lipids may impact the associated membrane and viral process. For example, hepatitis C virus (HCV) causes a specific, large-fold increase in the steady-state abundance of intracellular desmosterol, an immediate precursor of cholesterol, resulting in increased fluidity of the membrane where HCV RNA replication occurs. Here, we establish the mechanism responsible for HCV's effect on intracellular desmosterol, whereby the HCV NS3-4A protease controls activity of 24-dehydrocholesterol reductase (DHCR24), the enzyme that catalyzes conversion of desmosterol to cholesterol. Our cumulative evidence for the proposed mechanism includes immunofluorescence microscopy experiments showing co-occurrence of DHCR24 and HCV NS3-4A protease; formation of an additional, faster-migrating DHCR24 species (DHCR24*) in cells harboring a HCV subgenomic replicon RNA or ectopically expressing NS3-4A; and biochemical evidence that NS3-4A cleaves DHCR24 to produce DHCR24* in vitro and in vivo. We further demonstrate that NS3-4A cleaves DHCR24 between residues Cys91 and Thr92 and show that this reduces the intracellular conversion of desmosterol to cholesterol. Together, these studies demonstrate that NS3-4A directly cleaves DHCR24 and that this results in the enrichment of desmosterol in the membranes where NS3-4A and DHCR24 co-occur. Overall, this suggests a model in which HCV directly regulates the lipid environment for RNA replication through direct effects on the host lipid metabolism.
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Affiliation(s)
- Lorillee Tallorin
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Valerie A Villareal
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Chih-Yun Hsia
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Mary A Rodgers
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Dominique J Burri
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Marc-Philipp Pfeil
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Paula Montero Llopis
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Brett D Lindenbach
- Department of Microbial Pathogenesis, Yale Medical School, New Haven, Connecticut, USA
| | - Priscilla L Yang
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
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Pascolutti R, Erlandson SC, Burri DJ, Zheng S, Kruse AC. Mapping and engineering the interaction between adiponectin and T-cadherin. J Biol Chem 2020; 295:2749-2759. [PMID: 31915248 PMCID: PMC7049961 DOI: 10.1074/jbc.ra119.010970] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/19/2019] [Indexed: 11/06/2022] Open
Abstract
Adiponectin is a highly abundant protein hormone secreted by adipose tissue. It elicits diverse biological responses, including anti-diabetic, anti-inflammatory, anti-tumor, and anti-atherosclerotic effects. Adiponectin consists of a globular domain and a collagen-like domain, and it occurs in three major oligomeric forms that self-assemble: trimers, hexamers, and high-molecular-weight oligomers. Adiponectin has been reported to bind to two seven-transmembrane domain receptors, AdipoR1 and AdipoR2, as well as to the protein T-cadherin, which is highly expressed in the cardiovascular system and binds only the high-molecular-weight form of adiponectin. The molecular mechanisms underlying this specificity remain unclear. Here we used a combination of X-ray crystallography and protein engineering to define the details of adiponectin's interaction with T-cadherin. We found that T-cadherin binds to the globular domain of adiponectin, relying on structural stabilization of this domain by bound metal ions. Moreover, we show that the adiponectin globular domain can be engineered to enhance its binding affinity for T-cadherin. These results help to define the molecular basis for the interaction between adiponectin and T-cadherin, and our engineered globular domain variants may be useful tools for further investigating adiponectin's functions.
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Affiliation(s)
- Roberta Pascolutti
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Sarah C Erlandson
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Dominique J Burri
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Sanduo Zheng
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115.
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de Wispelaere M, Carocci M, Burri DJ, Neidermyer WJ, Olson CM, Roggenbach I, Liang Y, Wang J, Whelan SPJ, Gray NS, Yang PL. A broad-spectrum antiviral molecule, QL47, selectively inhibits eukaryotic translation. J Biol Chem 2020; 295:1694-1703. [PMID: 31914414 PMCID: PMC7008383 DOI: 10.1074/jbc.ra119.011132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/16/2019] [Indexed: 12/13/2022] Open
Abstract
Small-molecule inhibitors of translation are critical tools to study the molecular mechanisms of protein synthesis. In this study, we sought to characterize how QL47, a host-targeted, small-molecule antiviral agent, inhibits steady-state viral protein expression. We demonstrate that this small molecule broadly inhibits both viral and host protein synthesis and targets a translation step specific to eukaryotic cells. We show that QL47 inhibits protein neosynthesis initiated by both canonical cap-driven and noncanonical initiation strategies, most likely by targeting an early step in translation elongation. Our findings thus establish QL47 as a new small-molecule inhibitor that can be utilized to probe the eukaryotic translation machinery and that can be further developed as a new therapeutic agent.
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Affiliation(s)
- Mélissanne de Wispelaere
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Margot Carocci
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Dominique J Burri
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - William J Neidermyer
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Calla M Olson
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Imme Roggenbach
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Yanke Liang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Jinhua Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Sean P J Whelan
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Nathanael S Gray
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Priscilla L Yang
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115.
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Abstract
Arenaviruses are a large group of emerging viruses including several causative agents of severe hemorrhagic fevers with high mortality in man. Considering the number of people affected and the currently limited therapeutic options, novel efficacious therapeutics against arenaviruses are urgently needed. Over the past decade, significant advances in knowledge about the basic virology of arenaviruses have been accompanied by the development of novel therapeutics targeting different steps of the arenaviral life cycle. High-throughput, small-molecule screens identified potent and broadly active inhibitors of arenavirus entry that were instrumental for the dissection of unique features of arenavirus fusion. Novel inhibitors of arenavirus replication have been successfully tested in animal models and hold promise for application in humans. Late in the arenavirus life cycle, the proteolytic processing of the arenavirus envelope glycoprotein precursor and cellular factors critically involved virion assembly and budding provide further promising 'druggable' targets for novel therapeutics to combat human arenavirus infection.
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Affiliation(s)
- Antonella Pasquato
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
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Burri DJ, Pasquato A, da Palma JR, Igonet S, Oldstone MBA, Kunz S. The role of proteolytic processing and the stable signal peptide in expression of the Old World arenavirus envelope glycoprotein ectodomain. Virology 2012; 436:127-33. [PMID: 23218200 DOI: 10.1016/j.virol.2012.10.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [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] [Received: 08/29/2012] [Revised: 09/21/2012] [Accepted: 10/30/2012] [Indexed: 11/18/2022]
Abstract
Maturation of the arenavirus GP precursor (GPC) involves proteolytic processing by cellular signal peptidase and the proprotein convertase subtilisin kexin isozyme 1 (SKI-1)/site 1 protease (S1P), yielding a tripartite complex comprised of a stable signal peptide (SSP), the receptor-binding GP1, and the fusion-active transmembrane GP2. Here we investigated the roles of SKI-1/S1P processing and SSP in the biosynthesis of the recombinant GP ectodomains of lymphocytic choriomeningitis virus (LCMV) and Lassa virus (LASV). When expressed in mammalian cells, the LCMV and LASV GP ectodomains underwent processing by SKI-1/S1P, followed by dissociation of GP1 from GP2. The GP2 ectodomain spontaneously formed trimers as revealed by chemical cross-linking. The endogenous SSP, known to be crucial for maturation and transport of full-length arenavirus GPC was dispensable for processing and secretion of the soluble GP ectodomain, suggesting a specific role of SSP in the stable prefusion conformation and transport of full-length GPC.
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Affiliation(s)
- Dominique J Burri
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne CH-1011, Switzerland
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Burri DJ, Pasqual G, Rochat C, Seidah NG, Pasquato A, Kunz S. Molecular characterization of the processing of arenavirus envelope glycoprotein precursors by subtilisin kexin isozyme-1/site-1 protease. J Virol 2012; 86:4935-46. [PMID: 22357276 PMCID: PMC3347368 DOI: 10.1128/jvi.00024-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [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: 01/05/2012] [Accepted: 02/14/2012] [Indexed: 01/27/2023] Open
Abstract
A crucial step in the life cycle of arenaviruses is the biosynthesis of the mature fusion-active viral envelope glycoprotein (GP) that is essential for virus-host cell attachment and entry. The maturation of the arenavirus GP precursor (GPC) critically depends on proteolytic processing by the cellular proprotein convertase (PC) subtilisin kexin isozyme-1 (SKI-1)/site-1 protease (S1P). Here we undertook a molecular characterization of the SKI-1/S1P processing of the GPCs of the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) and the pathogenic Lassa virus (LASV). Previous studies showed that the GPC of LASV undergoes processing in the endoplasmic reticulum (ER)/cis-Golgi compartment, whereas the LCMV GPC is cleaved in a late Golgi compartment. Herein we confirm these findings and provide evidence that the SKI-1/S1P recognition site RRLL, present in the SKI-1/S1P prodomain and LASV GPC, but not in the LCMV GPC, is crucial for the processing of the LASV GPC in the ER/cis-Golgi compartment. Our structure-function analysis revealed that the cleavage of arenavirus GPCs, but not cellular substrates, critically depends on the autoprocessing of SKI-1/S1P, suggesting differences in the processing of cellular and viral substrates. Deletion mutagenesis showed that the transmembrane and intracellular domains of SKI-1/S1P are dispensable for arenavirus GPC processing. The expression of a soluble form of the protease in SKI-I/S1P-deficient cells resulted in the efficient processing of arenavirus GPCs and rescued productive virus infection. However, exogenous soluble SKI-1/S1P was unable to process LCMV and LASV GPCs displayed at the surface of SKI-I/S1P-deficient cells, indicating that GPC processing occurs in an intracellular compartment. In sum, our study reveals important differences in the SKI-1/S1P processing of viral and cellular substrates.
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Affiliation(s)
- Dominique J. Burri
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Giulia Pasqual
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Cylia Rochat
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Nabil G. Seidah
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Canada
| | - Antonella Pasquato
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Stefan Kunz
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
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