1
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Hendershot LM, Buck TM, Brodsky JL. The Essential Functions of Molecular Chaperones and Folding Enzymes in Maintaining Endoplasmic Reticulum Homeostasis. J Mol Biol 2024; 436:168418. [PMID: 38143019 DOI: 10.1016/j.jmb.2023.168418] [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: 10/16/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
It has been estimated that up to one-third of the proteins encoded by the human genome enter the endoplasmic reticulum (ER) as extended polypeptide chains where they undergo covalent modifications, fold into their native structures, and assemble into oligomeric protein complexes. The fidelity of these processes is critical to support organellar, cellular, and organismal health, and is perhaps best underscored by the growing number of disease-causing mutations that reduce the fidelity of protein biogenesis in the ER. To meet demands encountered by the diverse protein clientele that mature in the ER, this organelle is populated with a cadre of molecular chaperones that prevent protein aggregation, facilitate protein disulfide isomerization, and lower the activation energy barrier of cis-trans prolyl isomerization. Components of the lectin (glycan-binding) chaperone system also reside within the ER and play numerous roles during protein biogenesis. In addition, the ER houses multiple homologs of select chaperones that can recognize and act upon diverse peptide signatures. Moreover, redundancy helps ensure that folding-compromised substrates are unable to overwhelm essential ER-resident chaperones and enzymes. In contrast, the ER in higher eukaryotic cells possesses a single member of the Hsp70, Hsp90, and Hsp110 chaperone families, even though several homologs of these molecules reside in the cytoplasm. In this review, we discuss specific functions of the many factors that maintain ER quality control, highlight some of their interactions, and describe the vulnerabilities that arise from the absence of multiple members of some chaperone families.
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Affiliation(s)
- Linda M Hendershot
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States.
| | - Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
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2
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Rao PG, Lambert GS, Upadhyay C. Broadly neutralizing antibody epitopes on HIV-1 particles are exposed after virus interaction with host cells. J Virol 2023; 97:e0071023. [PMID: 37681958 PMCID: PMC10537810 DOI: 10.1128/jvi.00710-23] [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: 05/12/2023] [Accepted: 07/07/2023] [Indexed: 09/09/2023] Open
Abstract
The envelope (Env) glycoproteins on HIV-1 virions are the sole target of broadly neutralizing antibodies (bNAbs) and the focus of vaccines. However, many cross-reactive conserved epitopes are often occluded on virus particles, contributing to the evasion of humoral immunity. This study aimed to identify the Env epitopes that are exposed/occluded on HIV-1 particles and to investigate the mechanisms contributing to their masking. Using a flow cytometry-based assay, three HIV-1 isolates, and a panel of antibodies, we show that only select epitopes, including V2i, the gp120-g41 interface, and gp41-MPER, are accessible on HIV-1 particles, while V3, V2q, and select CD4bs epitopes are masked. These epitopes become accessible after allosteric conformational changes are induced by the pre-binding of select Abs, prompting us to test if similar conformational changes are required for these Abs to exhibit their neutralization capability. We tested HIV-1 neutralization where the virus-mAb mix was pre-incubated/not pre-incubated for 1 hour prior to adding the target cells. Similar levels of neutralization were observed under both assay conditions, suggesting that the interaction between virus and target cells sensitizes the virions for neutralization via bNAbs. We further show that lectin-glycan interactions can also expose these epitopes. However, this effect is dependent on the lectin specificity. Given that, bNAbs are ideal for providing sterilizing immunity and are the goal of current HIV-1 vaccine efforts, these data offer insight on how HIV-1 may occlude these vulnerable epitopes from the host immune response. In addition, the findings can guide the formulation of effective antibody combinations for therapeutic use. IMPORTANCE The human immunodeficiency virus (HIV-1) envelope (Env) glycoprotein mediates viral entry and is the sole target of neutralizing antibodies. Our data suggest that antibody epitopes including V2q (e.g., PG9, PGT145), CD4bs (e.g., VRC01, 3BNC117), and V3 (2219, 2557) are masked on HIV-1 particles. The PG9 and 2219 epitopes became accessible for binding after conformational unmasking was induced by the pre-binding of select mAbs. Attempts to understand the masking mechanism led to the revelation that interaction between virus and host cells is needed to sensitize the virions for neutralization by broadly neutralizing antibodies (bNAbs). These data provide insight on how bNAbs may gain access to these occluded epitopes to exert their neutralization effects and block HIV-1 infection. These findings have important implications for the way we evaluate the neutralizing efficacy of antibodies and can potentially guide vaccine design.
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Affiliation(s)
- Priyanka Gadam Rao
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Gregory S. Lambert
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chitra Upadhyay
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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3
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Chien YC, Wang YS, Sridharan D, Kuo CW, Chien CT, Uchihashi T, Kato K, Angata T, Meng TC, Hsu STD, Khoo KH. High Density of N- and O-Glycosylation Shields and Defines the Structural Dynamics of the Intrinsically Disordered Ectodomain of Receptor-type Protein Tyrosine Phosphatase Alpha. JACS AU 2023; 3:1864-1875. [PMID: 37502146 PMCID: PMC10369406 DOI: 10.1021/jacsau.3c00124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/01/2023] [Accepted: 06/01/2023] [Indexed: 07/29/2023]
Abstract
The intracellular phosphatase domain of the receptor-type protein tyrosine phosphatase alpha (PTPRA) is known to regulate various signaling pathways related to cell adhesion through c-Src kinase activation. In contrast, the functional significance of its relatively short, intrinsically disordered, and heavily glycosylated ectodomain remains unclear. Through detailed mass spectrometry analyses of a combination of protease and glycosidase digests, we now provide the first experimental evidence for its site-specific glycosylation pattern. This includes the occurrence of O-glycan at the N-glycosylation sequon among the more than 30 O-glycosylation sites confidently identified beside the 7 N-glycosylation sites. The closely spaced N- and O-glycans appear to have mutually limited the extent of further galactosylation and sialylation. An immature smaller form of full-length PTPRA was found to be deficient in O-glycosylation, most likely due to failure to transit the Golgi. N-glycosylation, on the other hand, is dispensable for cell surface expression and contributes less than the extensive O-glycosylation to the overall solution structure of the ectodomain. The glycosylation information is combined with the overall structural features of the ectodomain derived from small-angle X-ray scattering and high-speed atomic force microscopy monitoring to establish a dynamic structural model of the densely glycosylated PTPRA ectodomain. The observed high structural flexibility, as manifested by continuous transitioning from fully to partially extended and fold-back conformations, suggests that the receptor-type phosphatase is anchored to the membrane and kept mostly at a monomeric state through an ectodomain shaped and fully shielded by glycosylation.
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Affiliation(s)
- Yu-Chun Chien
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 10617, Taiwan
| | - Yong-Sheng Wang
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 10617, Taiwan
| | - Deepa Sridharan
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chu-Wei Kuo
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chih-Ta Chien
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Takayuki Uchihashi
- Department
of Physics, Nagoya University, Nagoya 464-8602, Japan
- Exploratory
Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
| | - Koichi Kato
- Exploratory
Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
- Institute
for Molecular Science, National Institutes
of Natural Sciences, Okazaki 444-8787, Japan
- Graduate
School of Pharmaceutical Sciences, Nagoya
City University, Nagoya 467-8603, Japan
| | - Takashi Angata
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 10617, Taiwan
| | - Tzu-Ching Meng
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 10617, Taiwan
| | - Shang-Te Danny Hsu
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 10617, Taiwan
- International
Institute for Sustainability with Knotted Chiral Meta Matter, Hiroshima University, Higashihiroshima 739-8527, Japan
| | - Kay-Hooi Khoo
- Institute
of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 10617, Taiwan
- Exploratory
Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
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4
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Rao PG, Lambert GS, Upadhyay C. Broadly Neutralizing Antibody Epitopes on HIV-1 Particles are exposed after Virus Interaction with Host Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524996. [PMID: 36711466 PMCID: PMC9882293 DOI: 10.1101/2023.01.20.524996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The envelope glycoproteins (Env) on HIV-1 virions are the sole target of broadly neutralizing antibodies (bNAb) and the focus of vaccines. However, many cross-reactive conserved epitopes are often occluded on virus particles, contributing to the evasion of humoral immunity. This study aimed to identify the Env epitopes that are exposed/occluded on HIV-1 particles and to investigate the mechanisms contributing to their masking. Using a flow cytometry-based assay, three HIV-1 isolates, and a panel of antibodies, we show that only select epitopes including V2i, gp120-g41 interface, and gp41-MPER are accessible on HIV-1 particles, while V3, V2q, and select CD4bs epitopes are masked. These epitopes become accessible after allosteric conformational changes are induced by pre-binding of select Abs, prompting us to test if similar conformational changes are required for these Abs to exhibit their neutralization capability. We tested HIV-1 neutralization where virus-mAb mix was pre-incubated/not pre-incubated for one hour prior to adding the target cells. Similar levels of neutralization were observed under both assay conditions, suggesting that the interaction between virus and target cells sensitizes the virions for neutralization via bNAbs. We further show that lectin-glycan interactions can also expose these epitopes. However, this effect is dependent on the lectin specificity. Given that, bNAbs are the ideal for providing sterilizing immunity and are the goal of current HIV-1 vaccine efforts, these data offer insight on how HIV-1 may occlude these vulnerable epitopes from the host immune response. In addition, the findings can guide the formulation of effective antibody combinations for therapeutic use.
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5
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Gansemer ER, Rutkowski DT. Pathways Linking Nicotinamide Adenine Dinucleotide Phosphate Production to Endoplasmic Reticulum Protein Oxidation and Stress. Front Mol Biosci 2022; 9:858142. [PMID: 35601828 PMCID: PMC9114485 DOI: 10.3389/fmolb.2022.858142] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
The endoplasmic reticulum (ER) lumen is highly oxidizing compared to other subcellular compartments, and maintaining the appropriate levels of oxidizing and reducing equivalents is essential to ER function. Both protein oxidation itself and other essential ER processes, such as the degradation of misfolded proteins and the sequestration of cellular calcium, are tuned to the ER redox state. Simultaneously, nutrients are oxidized in the cytosol and mitochondria to power ATP generation, reductive biosynthesis, and defense against reactive oxygen species. These parallel needs for protein oxidation in the ER and nutrient oxidation in the cytosol and mitochondria raise the possibility that the two processes compete for electron acceptors, even though they occur in separate cellular compartments. A key molecule central to both processes is NADPH, which is produced by reduction of NADP+ during nutrient catabolism and which in turn drives the reduction of components such as glutathione and thioredoxin that influence the redox potential in the ER lumen. For this reason, NADPH might serve as a mediator linking metabolic activity to ER homeostasis and stress, and represent a novel form of mitochondria-to-ER communication. In this review, we discuss oxidative protein folding in the ER, NADPH generation by the major pathways that mediate it, and ER-localized systems that can link the two processes to connect ER function to metabolic activity.
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Affiliation(s)
- Erica R. Gansemer
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - D. Thomas Rutkowski
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
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6
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Fedorov AN. Biosynthetic Protein Folding and Molecular Chaperons. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:S128-S19. [PMID: 35501992 DOI: 10.1134/s0006297922140115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The problem of linear polypeptide chain folding into a unique tertiary structure is one of the fundamental scientific challenges. The process of folding cannot be fully understood without its biological context, especially for big multidomain and multisubunit proteins. The principal features of biosynthetic folding are co-translational folding of growing nascent polypeptide chains and involvement of molecular chaperones in the process. The review summarizes available data on the early events of nascent chain folding, as well as on later advanced steps, including formation of elements of native structure. The relationship between the non-uniformity of translation rate and folding of the growing polypeptide is discussed. The results of studies on the effect of biosynthetic folding features on the parameters of folding as a physical process, its kinetics and mechanisms, are presented. Current understanding and hypotheses on the relationship of biosynthetic folding with the fundamental physical parameters and current views on polypeptide folding in the context of energy landscapes are discussed.
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Affiliation(s)
- Alexey N Fedorov
- Federal Research Center "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow, 119071, Russia.
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7
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Upadhyay C, Rao PG, Feyznezhad R. Dual Role of HIV-1 Envelope Signal Peptide in Immune Evasion. Viruses 2022; 14:v14040808. [PMID: 35458538 PMCID: PMC9030904 DOI: 10.3390/v14040808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 12/10/2022] Open
Abstract
HIV-1 Env signal peptide (SP) is an important contributor to Env functions. Env is generated from Vpu/Env encoded bicistronic mRNA such that the 5′ end of Env-N-terminus, that encodes for Env-SP overlaps with 3′ end of Vpu. Env SP displays high sequence diversity, which translates into high variability in Vpu sequence. This study aimed to understand the effect of sequence polymorphism in the Vpu-Env overlapping region (VEOR) on the functions of two vital viral proteins: Vpu and Env. We used infectious molecular clone pNL4.3-CMU06 and swapped its SP (or VEOR) with that from other HIV-1 isolates. Swapping VEOR did not affect virus production in the absence of tetherin however, presence of tetherin significantly altered the release of virus progeny. VEOR also altered Vpu’s ability to downregulate CD4 and tetherin. We next tested the effect of these swaps on Env functions. Analyzing the binding of monoclonal antibodies to membrane embedded Env revealed changes in the antigenic landscape of swapped Envs. These swaps affected the oligosaccharide composition of Env-N-glycans as shown by changes in DC-SIGN-mediated virus transmission. Our study suggests that genetic diversity in VEOR plays an important role in the differential pathogenesis and also assist in immune evasion by altering Env epitope exposure.
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8
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Mahmood F, Xu R, Awan MUN, Song Y, Han Q, Xia X, Zhang J. PDIA3: Structure, functions and its potential role in viral infections. Biomed Pharmacother 2021; 143:112110. [PMID: 34474345 DOI: 10.1016/j.biopha.2021.112110] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 02/08/2023] Open
Abstract
The catalysis of disulphide (SS) bonds is the most important characteristic of protein disulphide isomerase (PDI) family. Catalysis occurs in the endoplasmic reticulum, which contains many proteins, most of which are secretory in nature and that have at least one s-s bond. Protein disulphide isomerase A3 (PDIA3) is a member of the PDI family that acts as a chaperone. PDIA3 is highly expressed in response to cellular stress, and also intercept the apoptotic cellular death related to endoplasmic reticulum (ER) stress, and protein misfolding. PDIA3 expression is elevated in almost 70% of cancers and its expression has been linked with overall low cell invasiveness, survival and metastasis. Viral diseases present a significant public health threat. The presence of PDIA3 on the cell surface helps different viruses to enter the cells and also helps in replication. Therefore, inhibitors of PDIA3 have great potential to interfere with viral infections. In this review, we summarize what is known about the basic structure, functions and role of PDIA3 in viral infections. The review will inspire studies of pathogenic mechanisms and drug targeting to counter viral diseases.
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Affiliation(s)
- Faisal Mahmood
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Ruixian Xu
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Maher Un Nisa Awan
- Laboratory of Molecular Neurobiology, Medical Faculty, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Yuzhu Song
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Qinqin Han
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Xueshan Xia
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China.
| | - Jinyang Zhang
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China.
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9
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McCaul N, Quandte M, Bontjer I, van Zadelhoff G, Land A, Crooks ET, Binley JM, Sanders RW, Braakman I. Intramolecular quality control: HIV-1 envelope gp160 signal-peptide cleavage as a functional folding checkpoint. Cell Rep 2021; 36:109646. [PMID: 34469718 DOI: 10.1016/j.celrep.2021.109646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/28/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
Removal of the membrane-tethering signal peptides that target secretory proteins to the endoplasmic reticulum is a prerequisite for proper folding. While generally thought to be removed co-translationally, we report two additional post-targeting functions for the HIV-1 gp120 signal peptide, which remains attached until gp120 folding triggers its removal. First, the signal peptide improves folding fidelity by enhancing conformational plasticity of gp120 by driving disulfide isomerization through a redox-active cysteine. Simultaneously, the signal peptide delays folding by tethering the N terminus to the membrane, until assembly with the C terminus. Second, its carefully timed cleavage represents intramolecular quality control and ensures release of (only) natively folded gp120. Postponed cleavage and the redox-active cysteine are both highly conserved and important for viral fitness. Considering the ∼15% proteins with signal peptides and the frequency of N-to-C contacts in protein structures, these regulatory roles of signal peptides are bound to be more common in secretory-protein biogenesis.
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Affiliation(s)
- Nicholas McCaul
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Matthias Quandte
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Ilja Bontjer
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity, 1105 Amsterdam, the Netherlands
| | - Guus van Zadelhoff
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Aafke Land
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Ema T Crooks
- San Diego Biomedical Research Institute, 10865 Road to the Cure #100, San Diego, CA, USA
| | - James M Binley
- San Diego Biomedical Research Institute, 10865 Road to the Cure #100, San Diego, CA, USA
| | - Rogier W Sanders
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity, 1105 Amsterdam, the Netherlands; Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands.
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10
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A slowly cleaved viral signal peptide acts as a protein-integral immune evasion domain. Nat Commun 2021; 12:2061. [PMID: 33824318 PMCID: PMC8024260 DOI: 10.1038/s41467-021-21983-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/18/2021] [Indexed: 02/05/2023] Open
Abstract
Stress can induce cell surface expression of MHC-like ligands, including MICA, that activate NK cells. Human cytomegalovirus (HCMV) glycoprotein US9 downregulates the activating immune ligand MICA*008 to avoid NK cell activation, but the underlying mechanism remains unclear. Here, we show that the N-terminal signal peptide is the major US9 functional domain targeting MICA*008 to proteasomal degradation. The US9 signal peptide is cleaved with unusually slow kinetics and this transiently retained signal peptide arrests MICA*008 maturation in the endoplasmic reticulum (ER), and indirectly induces its degradation via the ER quality control system and the SEL1L-HRD1 complex. We further identify an accessory, signal peptide-independent US9 mechanism that directly binds MICA*008 and SEL1L. Collectively, we describe a dual-targeting immunoevasin, demonstrating that signal peptides can function as protein-integral effector domains. Glycoprotein US9 of human cytomegalovirus downregulates the activating immune ligand MICA*008 to avoid NK cell activation. Here, Seidel et al. show that the signal peptide of US9 is cleaved unusually slowly, causing MICA*008 to be retained in the endoplasmic reticulum (ER) and degraded via the ER quality control system.
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11
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Intracellular Redox-Modulated Pathways as Targets for Effective Approaches in the Treatment of Viral Infection. Int J Mol Sci 2021; 22:ijms22073603. [PMID: 33808471 PMCID: PMC8036776 DOI: 10.3390/ijms22073603] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/19/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Host-directed therapy using drugs that target cellular pathways required for virus lifecycle or its clearance might represent an effective approach for treating infectious diseases. Changes in redox homeostasis, including intracellular glutathione (GSH) depletion, are one of the key events that favor virus replication and contribute to the pathogenesis of virus-induced disease. Redox homeostasis has an important role in maintaining an appropriate Th1/Th2 balance, which is necessary to mount an effective immune response against viral infection and to avoid excessive inflammatory responses. It is known that excessive production of reactive oxygen species (ROS) induced by viral infection activates nuclear factor (NF)-kB, which orchestrates the expression of viral and host genes involved in the viral replication and inflammatory response. Moreover, redox-regulated protein disulfide isomerase (PDI) chaperones have an essential role in catalyzing formation of disulfide bonds in viral proteins. This review aims at describing the role of GSH in modulating redox sensitive pathways, in particular that mediated by NF-kB, and PDI activity. The second part of the review discusses the effectiveness of GSH-boosting molecules as broad-spectrum antivirals acting in a multifaceted way that includes the modulation of immune and inflammatory responses.
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12
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HIV-1 Envelope Glycosylation and the Signal Peptide. Vaccines (Basel) 2021; 9:vaccines9020176. [PMID: 33669676 PMCID: PMC7922494 DOI: 10.3390/vaccines9020176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/07/2021] [Accepted: 02/16/2021] [Indexed: 12/25/2022] Open
Abstract
The RV144 trial represents the only vaccine trial to demonstrate any protective effect against HIV-1 infection. While the reason(s) for this protection are still being evaluated, it serves as justification for widespread efforts aimed at developing new, more effective HIV-1 vaccines. Advances in our knowledge of HIV-1 immunogens and host antibody responses to these immunogens are crucial to informing vaccine design. While the envelope (Env) protein is the only viral protein present on the surface of virions, it exists in a complex trimeric conformation and is decorated with an array of variable N-linked glycans, making it an important but difficult target for vaccine design. Thus far, efforts to elicit a protective humoral immune response using structural mimics of native Env trimers have been unsuccessful. Notably, the aforementioned N-linked glycans serve as a component of many of the epitopes crucial for the induction of potentially protective broadly neutralizing antibodies (bnAbs). Thus, a greater understanding of Env structural determinants, most critically Env glycosylation, will no doubt be of importance in generating effective immunogens. Recent studies have identified the HIV-1 Env signal peptide (SP) as an important contributor to Env glycosylation. Further investigation into the mechanisms by which the SP directs glycosylation will be important, both in the context of understanding HIV-1 biology and in order to inform HIV-1 vaccine design.
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13
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Signal peptide of HIV-1 envelope modulates glycosylation impacting exposure of V1V2 and other epitopes. PLoS Pathog 2020; 16:e1009185. [PMID: 33370382 PMCID: PMC7793277 DOI: 10.1371/journal.ppat.1009185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/08/2021] [Accepted: 11/24/2020] [Indexed: 11/19/2022] Open
Abstract
HIV-1 envelope (Env) is a trimer of gp120-gp41 heterodimers, synthesized from a precursor gp160 that contains an ER-targeting signal peptide (SP) at its amino-terminus. Each trimer is swathed by ~90 N-linked glycans, comprising complex-type and oligomannose-type glycans, which play an important role in determining virus sensitivity to neutralizing antibodies. We previously examined the effects of single point SP mutations on Env properties and functions. Here, we aimed to understand the impact of the SP diversity on glycosylation of virus-derived Env and virus neutralization by swapping SPs. Analyses of site-specific glycans revealed that SP swapping altered Env glycan content and occupancy on multiple N-linked glycosites, including conserved N156 and N160 glycans in the V1V2 region at the Env trimer apex and N88 at the trimer base. Virus neutralization was also affected, especially by antibodies against V1V2, V3, and gp41. Likewise, SP swaps affected the recognition of soluble and cell-associated Env by antibodies targeting distinct V1V2 configurations, V3 crown, and gp41 epitopes. These data highlight the contribution of SP sequence diversity in shaping the Env glycan content and its impact on the configuration and accessibility of V1V2 and other Env epitopes. HIV-1 Env glycoprotein is produced by a precursor gp160 that has a signal peptide at its N-terminus. The SP is highly diverse among the HIV-1 isolates. This study presents site-specific analyses of N-linked glycosylation on HIV-1 envelope glycoproteins from infectious viruses produced with different envelope signal peptides. We show that signal peptide swapping alters the envelope glycan shield, including the conserved N156 and N160 glycans located in the V1V2 region on the trimer apex, to impact Env recognition and virus neutralization by antibodies. The data offer crucial insights into the role of signal peptide in the interplay between HIV-1 and antibodies and its potential utility to control Env glycosylation in the development of Env-based HIV-1 vaccine.
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14
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Margolin E, Oh YJ, Verbeek M, Naude J, Ponndorf D, Meshcheriakova YA, Peyret H, van Diepen MT, Chapman R, Meyers AE, Lomonossoff GP, Matoba N, Williamson A, Rybicki EP. Co-expression of human calreticulin significantly improves the production of HIV gp140 and other viral glycoproteins in plants. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2109-2117. [PMID: 32096288 PMCID: PMC7540014 DOI: 10.1111/pbi.13369] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 05/19/2023]
Abstract
Plant molecular farming (PMF) is rapidly gaining traction as a viable alternative to the currently accepted paradigm of producing biologics. While the platform is potentially cheaper and more scalable than conventional manufacturing systems, expression yields and appropriate post-translational modifications along the plant secretory pathway remain a challenge for certain proteins. Viral fusion glycoproteins in particular are often expressed at low yields in plants and, in some cases, may not be appropriately processed. Recently, however, transiently or stably engineering the host plant has shown promise as a strategy for producing heterologous proteins with more complex maturation requirements. In this study we investigated the co-expression of a suite of human chaperones to improve the production of a human immunodeficiency virus (HIV) type 1 soluble gp140 vaccine candidate in Nicotiana benthamiana plants. The co-expression of calreticulin (CRT) resulted in a dramatic increase in Env expression and ameliorated the endoplasmic reticulum (ER) stress response - as evidenced by lower transcript abundance of representative stress-responsive genes. The co-expression of CRT similarly improved accumulation of glycoproteins from Epstein-Barr virus (EBV), Rift Valley fever virus (RVFV) and chikungunya virus (CHIKV), suggesting that the endogenous chaperone machinery may impose a bottleneck for their production. We subsequently successfully combined the co-expression of human CRT with the transient expression of human furin, to enable the production of an appropriately cleaved HIV gp140 antigen. These transient plant host engineering strategies are a promising approach for the production of high yields of appropriately processed and cleaved viral glycoproteins.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Wellcome Trust Centre for Infectious Disease Research in AfricaUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Youngjun J. Oh
- Department of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Matthew Verbeek
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Jason Naude
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Daniel Ponndorf
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | | | - Hadrien Peyret
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | - Michiel T. van Diepen
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Ros Chapman
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Ann E. Meyers
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | | | - Nobuyuki Matoba
- Department of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Anna‐Lise Williamson
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Wellcome Trust Centre for Infectious Disease Research in AfricaUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Edward P. Rybicki
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
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15
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Mechanisms of Disulfide Bond Formation in Nascent Polypeptides Entering the Secretory Pathway. Cells 2020; 9:cells9091994. [PMID: 32872499 PMCID: PMC7565403 DOI: 10.3390/cells9091994] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/16/2022] Open
Abstract
Disulfide bonds are an abundant feature of proteins across all domains of life that are important for structure, stability, and function. In eukaryotic cells, a major site of disulfide bond formation is the endoplasmic reticulum (ER). How cysteines correctly pair during polypeptide folding to form the native disulfide bond pattern is a complex problem that is not fully understood. In this paper, the evidence for different folding mechanisms involved in ER-localised disulfide bond formation is reviewed with emphasis on events that occur during ER entry. Disulfide formation in nascent polypeptides is discussed with focus on (i) its mechanistic relationship with conformational folding, (ii) evidence for its occurrence at the co-translational stage during ER entry, and (iii) the role of protein disulfide isomerase (PDI) family members. This review highlights the complex array of cellular processes that influence disulfide bond formation and identifies key questions that need to be addressed to further understand this fundamental process.
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16
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Finger Y, Habich M, Gerlich S, Urbanczyk S, van de Logt E, Koch J, Schu L, Lapacz KJ, Ali M, Petrungaro C, Salscheider SL, Pichlo C, Baumann U, Mielenz D, Dengjel J, Brachvogel B, Hofmann K, Riemer J. Proteasomal degradation induced by DPP9-mediated processing competes with mitochondrial protein import. EMBO J 2020; 39:e103889. [PMID: 32815200 PMCID: PMC7527813 DOI: 10.15252/embj.2019103889] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 06/29/2020] [Accepted: 07/03/2020] [Indexed: 12/14/2022] Open
Abstract
Plasticity of the proteome is critical to adapt to varying conditions. Control of mitochondrial protein import contributes to this plasticity. Here, we identified a pathway that regulates mitochondrial protein import by regulated N-terminal processing. We demonstrate that dipeptidyl peptidases 8/9 (DPP8/9) mediate the N-terminal processing of adenylate kinase 2 (AK2) en route to mitochondria. We show that AK2 is a substrate of the mitochondrial disulfide relay, thus lacking an N-terminal mitochondrial targeting sequence and undergoing comparatively slow import. DPP9-mediated processing of AK2 induces its rapid proteasomal degradation and prevents cytosolic accumulation of enzymatically active AK2. Besides AK2, we identify more than 100 mitochondrial proteins with putative DPP8/9 recognition sites and demonstrate that DPP8/9 influence the cellular levels of a number of these proteins. Collectively, we provide in this study a conceptual framework on how regulated cytosolic processing controls levels of mitochondrial proteins as well as their dual localization to mitochondria and other compartments.
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Affiliation(s)
- Yannik Finger
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Markus Habich
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Sarah Gerlich
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Sophia Urbanczyk
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Erik van de Logt
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Julian Koch
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Laura Schu
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Kim Jasmin Lapacz
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Muna Ali
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | - Carmelina Petrungaro
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany
| | | | - Christian Pichlo
- Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Ulrich Baumann
- Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Dirk Mielenz
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Joern Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Bent Brachvogel
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Kay Hofmann
- Institute of Genetics, University of Cologne, Cologne, Germany
| | - Jan Riemer
- Institute of Biochemistry, Redox Biochemistry, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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17
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Kadokura H, Dazai Y, Fukuda Y, Hirai N, Nakamura O, Inaba K. Observing the nonvectorial yet cotranslational folding of a multidomain protein, LDL receptor, in the ER of mammalian cells. Proc Natl Acad Sci U S A 2020; 117:16401-16408. [PMID: 32601215 PMCID: PMC7368290 DOI: 10.1073/pnas.2004606117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Proteins have evolved by incorporating several structural units within a single polypeptide. As a result, multidomain proteins constitute a large fraction of all proteomes. Their domains often fold to their native structures individually and vectorially as each domain emerges from the ribosome or the protein translocation channel, leading to the decreased risk of interdomain misfolding. However, some multidomain proteins fold in the endoplasmic reticulum (ER) nonvectorially via intermediates with nonnative disulfide bonds, which were believed to be shuffled to native ones slowly after synthesis. Yet, the mechanism by which they fold nonvectorially remains unclear. Using two-dimensional (2D) gel electrophoresis and a conformation-specific antibody that recognizes a correctly folded domain, we show here that shuffling of nonnative disulfide bonds to native ones in the most N-terminal region of LDL receptor (LDLR) started at a specific timing during synthesis. Deletion analysis identified a region on LDLR that assisted with disulfide shuffling in the upstream domain, thereby promoting its cotranslational folding. Thus, a plasma membrane-bound multidomain protein has evolved a sequence that promotes the nonvectorial folding of its upstream domains. These findings demonstrate that nonvectorial folding of a multidomain protein in the ER of mammalian cells is more coordinated and elaborated than previously thought. Thus, our findings alter our current view of how a multidomain protein folds nonvectorially in the ER of living cells.
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Affiliation(s)
- Hiroshi Kadokura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan
| | - Yui Dazai
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan
| | - Yo Fukuda
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan
| | - Naoya Hirai
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan
| | - Orie Nakamura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan
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18
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Past and ongoing adaptation of human cytomegalovirus to its host. PLoS Pathog 2020; 16:e1008476. [PMID: 32384127 PMCID: PMC7239485 DOI: 10.1371/journal.ppat.1008476] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 05/20/2020] [Accepted: 03/13/2020] [Indexed: 12/18/2022] Open
Abstract
Cytomegaloviruses (order Herpesvirales) display remarkable species-specificity as a result of long-term co-evolution with their mammalian hosts. Human cytomegalovirus (HCMV) is exquisitely adapted to our species and displays high genetic diversity. We leveraged information on inter-species divergence of primate-infecting cytomegaloviruses and intra-species diversity of clinical isolates to provide a genome-wide picture of HCMV adaptation across different time-frames. During adaptation to the human host, core viral genes were commonly targeted by positive selection. Functional characterization of adaptive mutations in the primase gene (UL70) indicated that selection favored amino acid replacements that decrease viral replication in human fibroblasts, suggesting evolution towards viral temperance. HCMV intra-species diversity was largely governed by immune system-driven selective pressure, with several adaptive variants located in antigenic domains. A significant excess of positively selected sites was also detected in the signal peptides (SPs) of viral proteins, indicating that, although they are removed from mature proteins, SPs can contribute to viral adaptation. Functional characterization of one of these SPs indicated that adaptive variants modulate the timing of cleavage by the signal peptidase and the dynamics of glycoprotein intracellular trafficking. We thus used evolutionary information to generate experimentally-testable hypotheses on the functional effect of HCMV genetic diversity and we define modulators of viral phenotypes. Human cytomegalovirus (HCMV), which represents the most common infectious cause of birth defects, is perfectly adapted to infect humans. We performed a two-tier analysis of HCMV evolution, by describing selective events that occurred during HCMV adaptation to our species and by identifying more recently emerged adaptive variants in clinical isolates. We show that distinct viral genes were targeted by natural selection over different time frames and we generate a catalog of adaptive variants that represent candidate determinants of viral phenotypic variation. As a proof of concept, we show that adaptive changes in the viral primase modulate viral growth in vitro and that selected variants in the UL144 signal peptide affect glycoprotein intracellular trafficking.
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19
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Robinson PJ, Kanemura S, Cao X, Bulleid NJ. Protein secondary structure determines the temporal relationship between folding and disulfide formation. J Biol Chem 2020; 295:2438-2448. [PMID: 31953323 PMCID: PMC7039548 DOI: 10.1074/jbc.ra119.011983] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/16/2020] [Indexed: 11/06/2022] Open
Abstract
How and when disulfide bonds form in proteins relative to the stage of their folding is a fundamental question in cell biology. Two models describe this relationship: the folded precursor model, in which a nascent structure forms before disulfides do, and the quasi-stochastic model, where disulfides form prior to folding. Here we investigated oxidative folding of three structurally diverse substrates, β2-microglobulin, prolactin, and the disintegrin domain of ADAM metallopeptidase domain 10 (ADAM10), to understand how these mechanisms apply in a cellular context. We used a eukaryotic cell-free translation system in which we could identify disulfide isomers in stalled translation intermediates to characterize the timing of disulfide formation relative to translocation into the endoplasmic reticulum and the presence of non-native disulfides. Our results indicate that in a domain lacking secondary structure, disulfides form before conformational folding through a process prone to nonnative disulfide formation, whereas in proteins with defined secondary structure, native disulfide formation occurs after partial folding. These findings reveal that the nascent protein structure promotes correct disulfide formation during cotranslational folding.
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Affiliation(s)
- Philip J Robinson
- Institute of Molecular, Cell, and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Shingo Kanemura
- Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Xiaofei Cao
- Institute of Molecular, Cell, and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Neil J Bulleid
- Institute of Molecular, Cell, and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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20
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Seabright GE, Doores KJ, Burton DR, Crispin M. Protein and Glycan Mimicry in HIV Vaccine Design. J Mol Biol 2019; 431:2223-2247. [PMID: 31028779 PMCID: PMC6556556 DOI: 10.1016/j.jmb.2019.04.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/12/2019] [Accepted: 04/13/2019] [Indexed: 01/30/2023]
Abstract
Antigenic mimicry is a fundamental tenet of structure-based vaccinology. Vaccine strategies for the human immunodeficiency virus type 1 (HIV-1) focus on the mimicry of its envelope spike (Env) due to its exposed location on the viral membrane and role in mediating infection. However, the virus has evolved to minimize the immunogenicity of conserved epitopes on the envelope spike. This principle is starkly illustrated by the presence of an extensive array of host-derived glycans, which act to shield the underlying protein from antibody recognition. Despite these hurdles, a subset of HIV-infected individuals eventually develop broadly neutralizing antibodies that recognize these virally presented glycans. Effective HIV-1 immunogens are therefore likely to involve some degree of mimicry of both the protein and glycan components of Env. As such, considerable efforts have been made to characterize the structure of the envelope spike and its glycan shield. This review summarizes the recent progress made in this field, with an emphasis on our growing understanding of the factors shaping the glycan shield of Env derived from both virus and soluble immunogens. We argue that recombinant mimics of the envelope spike are currently capable of capturing many features of the native viral glycan shield. Finally, we explore strategies through which the immunogenicity of Env glycans may be enhanced in the development of future immunogens.
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Affiliation(s)
- Gemma E Seabright
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK; School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Katie J Doores
- Department of Infectious Diseases, King's College London, Guy's Hospital, London, SE1 9RT, UK
| | - Dennis R Burton
- Department of Immunology and Microbiology, the Scripps Centre for HIV/AIDS Vaccine Immunology and Immunogen Discovery (CHAVI-ID), International AIDS Vaccine Initiative Neutralizing Antibody Centre, Scripps Research, La Jolla, CA 92037, USA
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK; Department of Immunology and Microbiology, the Scripps Centre for HIV/AIDS Vaccine Immunology and Immunogen Discovery (CHAVI-ID), International AIDS Vaccine Initiative Neutralizing Antibody Centre, Scripps Research, La Jolla, CA 92037, USA.
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21
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Beitari S, Wang Y, Liu SL, Liang C. HIV-1 Envelope Glycoprotein at the Interface of Host Restriction and Virus Evasion. Viruses 2019; 11:v11040311. [PMID: 30935048 PMCID: PMC6521621 DOI: 10.3390/v11040311] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 12/15/2022] Open
Abstract
Without viral envelope proteins, viruses cannot enter cells to start infection. As the major viral proteins present on the surface of virions, viral envelope proteins are a prominent target of the host immune system in preventing and ultimately eliminating viral infection. In addition to the well-appreciated adaptive immunity that produces envelope protein-specific antibodies and T cell responses, recent studies have begun to unveil a rich layer of host innate immune mechanisms restricting viral entry. This review focuses on the exciting progress that has been made in this new direction of research, by discussing various known examples of host restriction of viral entry, and diverse viral countering strategies, in particular, the emerging role of viral envelope proteins in evading host innate immune suppression. We will also highlight the effective cooperation between innate and adaptive immunity to achieve the synergistic control of viral infection by targeting viral envelope protein and checking viral escape. Given that many of the related findings were made with HIV-1, we will use HIV-1 as the model virus to illustrate the basic principles and molecular mechanisms on host restriction targeting HIV-1 envelope protein.
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Affiliation(s)
- Saina Beitari
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4, Canada.
- Lady Davis Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada.
| | - Yimeng Wang
- Lady Davis Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada.
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada.
| | - Shan-Lu Liu
- Center for Retrovirus Research, Department of Veterinary Biosciences, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210, USA.
| | - Chen Liang
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4, Canada.
- Lady Davis Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada.
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada.
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22
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de Taeye SW, Go EP, Sliepen K, de la Peña AT, Badal K, Medina-Ramírez M, Lee WH, Desaire H, Wilson IA, Moore JP, Ward AB, Sanders RW. Stabilization of the V2 loop improves the presentation of V2 loop-associated broadly neutralizing antibody epitopes on HIV-1 envelope trimers. J Biol Chem 2019; 294:5616-5631. [PMID: 30728245 PMCID: PMC6462529 DOI: 10.1074/jbc.ra118.005396] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 01/15/2019] [Indexed: 11/16/2022] Open
Abstract
A successful HIV-1 vaccine will likely need to elicit broadly neutralizing antibodies (bNAbs) that target the envelope glycoprotein (Env) spike on the virus. Native-like recombinant Env trimers of the SOSIP design now serve as a platform for achieving this challenging goal. However, SOSIP trimers usually do not bind efficiently to the inferred germline precursors of bNAbs (gl-bNAbs). We hypothesized that the inherent flexibilities of the V1 and V2 variable loops in the Env trimer contribute to the poor recognition of gl-bNAb epitopes at the trimer apex that extensively involve V2 residues. To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and gl-bNAbs, we designed BG505 SOSIP.664 trimer variants containing newly created disulfide bonds intended to stabilize the V2 loop in an optimally antigenic configuration. The first variant, I184C/E190C, contained a new disulfide bond within the V2 loop, whereas the second variant, E153C/R178C, had a new disulfide bond that cross-linked V2 and V1. The resulting engineered native-like trimer variants were both more reactive with and were neutralized by V2 bNAbs and gl-bNAbs, a finding that may be valuable in the design of germline targeting and boosting trimer immunogens to create an antigenic conformation optimal for HIV vaccine development.
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Affiliation(s)
- Steven W de Taeye
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Eden P Go
- the Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Kwinten Sliepen
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Alba Torrents de la Peña
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Kimberly Badal
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Max Medina-Ramírez
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Wen-Hsin Lee
- the Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, and
| | - Heather Desaire
- the Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Ian A Wilson
- the Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, and
| | - John P Moore
- the Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Andrew B Ward
- the Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, and
| | - Rogier W Sanders
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands, .,the Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
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23
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Weed DJ, Dollery SJ, Komala Sari T, Nicola AV. Acidic pH Mediates Changes in Antigenic and Oligomeric Conformation of Herpes Simplex Virus gB and Is a Determinant of Cell-Specific Entry. J Virol 2018; 92:e01034-18. [PMID: 29925660 PMCID: PMC6096812 DOI: 10.1128/jvi.01034-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 02/07/2023] Open
Abstract
Herpes simplex virus (HSV) is an important human pathogen with a high worldwide seroprevalence. HSV enters epithelial cells, the primary site of infection, by a low-pH pathway. HSV glycoprotein B (gB) undergoes low pH-induced conformational changes, which are thought to drive membrane fusion. When neutralized back to physiological pH, these changes become reversible. Here, HSV-infected cells were subjected to short pulses of radiolabeling, followed by immunoprecipitation with a panel of gB monoclonal antibodies (MAbs), demonstrating that gB folds and oligomerizes rapidly and cotranslationally in the endoplasmic reticulum. Full-length gB from transfected cells underwent low-pH-triggered changes in oligomeric conformation in the absence of other viral proteins. MAbs to gB neutralized HSV entry into cells regardless of the pH dependence of the entry pathway, suggesting a conservation of gB function in distinct fusion mechanisms. The combination of heat and acidic pH triggered irreversible changes in the antigenic conformation of the gB fusion domain, while changes in the gB oligomer remained reversible. An elevated temperature alone was not sufficient to induce gB conformational change. Together, these results shed light on the conformation and function of the HSV-1 gB oligomer, which serves as part of the core fusion machinery during viral entry.IMPORTANCE Herpes simplex virus (HSV) causes infection of the mouth, skin, eyes, and genitals and establishes lifelong latency in humans. gB is conserved among all herpesviruses. HSV gB undergoes reversible conformational changes following exposure to acidic pH which are thought to mediate fusion and entry into epithelial cells. Here, we identified cotranslational folding and oligomerization of newly synthesized gB. A panel of antibodies to gB blocked both low-pH and pH-neutral entry of HSV, suggesting conserved conformational changes in gB regardless of cell entry route. Changes in HSV gB conformation were not triggered by increased temperature alone, in contrast to results with EBV gB. Acid pH-induced changes in the oligomeric conformation of gB are related but distinct from pH-triggered changes in gB antigenic conformation. These results highlight critical aspects of the class III fusion protein, gB, and inform strategies to block HSV infection at the level of fusion and entry.
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Affiliation(s)
- Darin J Weed
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Stephen J Dollery
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Tri Komala Sari
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Anthony V Nicola
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
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Margolin E, Chapman R, Williamson A, Rybicki EP, Meyers AE. Production of complex viral glycoproteins in plants as vaccine immunogens. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1531-1545. [PMID: 29890031 PMCID: PMC6097131 DOI: 10.1111/pbi.12963] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 05/19/2023]
Abstract
Plant molecular farming offers a cost-effective and scalable approach to the expression of recombinant proteins which has been proposed as an alternative to conventional production platforms for developing countries. In recent years, numerous proofs of concept have established that plants can produce biologically active recombinant proteins and immunologically relevant vaccine antigens that are comparable to those made in conventional expression systems. Driving many of these advances is the remarkable plasticity of the plant proteome which enables extensive engineering of the host cell, as well as the development of improved expression vectors facilitating higher levels of protein production. To date, the only plant-derived viral glycoprotein to be tested in humans is the influenza haemagglutinin which expresses at ~50 mg/kg. However, many other viral glycoproteins that have potential as vaccine immunogens only accumulate at low levels in planta. A critical consideration for the production of many of these proteins in heterologous expression systems is the complexity of post-translational modifications, such as control of folding, glycosylation and disulphide bridging, which is required to reproduce the native glycoprotein structure. In this review, we will address potential shortcomings of plant expression systems and discuss strategies to optimally exploit the technology for the production of immunologically relevant and structurally authentic glycoproteins for use as vaccine immunogens.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Ros Chapman
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Anna‐Lise Williamson
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Edward P. Rybicki
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Ann E. Meyers
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
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25
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Harnessing post-translational modifications for next-generation HIV immunogens. Biochem Soc Trans 2018; 46:691-698. [PMID: 29784645 DOI: 10.1042/bst20170394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/10/2018] [Accepted: 04/17/2018] [Indexed: 12/12/2022]
Abstract
The extensive post-translational modifications of the envelope spikes of the human immunodeficiency virus (HIV) present considerable challenges and opportunities for HIV vaccine design. These oligomeric glycoproteins typically have over 30 disulfide bonds and around a 100 N-linked glycosylation sites, and are functionally dependent on protease cleavage within the secretory system. The resulting mature structure adopts a compact fold with the vast majority of its surface obscured by a protective shield of glycans which can be targeted by broadly neutralizing antibodies (bnAbs). Despite the notorious heterogeneity of glycosylation, rare B-cell lineages can evolve to utilize and cope with viral glycan diversity, and these structures therefore present promising targets for vaccine design. The latest generation of recombinant envelope spike mimetics contains re-engineered post-translational modifications to present stable antigens to guide the development of bnAbs by vaccination.
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26
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Yolitz J, Schwing C, Chang J, Van Ryk D, Nawaz F, Wei D, Cicala C, Arthos J, Fauci AS. Signal peptide of HIV envelope protein impacts glycosylation and antigenicity of gp120. Proc Natl Acad Sci U S A 2018; 115:2443-2448. [PMID: 29463753 PMCID: PMC5877976 DOI: 10.1073/pnas.1722627115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The HIV-1 envelope protein (Env) of early-replicating viruses encodes several distinct transmission signatures. One such signature involves a reduced number of potential N-linked glycosylation sites (PNGs). This transmission signature underscores the importance of posttranslational modifications in the fitness of early-replicating isolates. An additional signature in Env involves the overrepresentation of basic amino acid residues at a specific position in the Env signal peptide (SP). In this report, we investigated the potential impact of this SP signature on gp120 glycosylation and antigenicity. Two recombinant gp120s were constructed, one derived from an isolate that lacks this signature and a second from an early-replicating isolate that includes this signature. Chimeric gp120s were also constructed in which the two SPs were swapped between the isolates. All four gp120s were probed with glycan-, structure- and receptor- specific probes in a surface plasmon resonance binding assay. We found that the SP of Env influences qualitative aspects of Env glycosylation that in turn affect the antigenicity of Env in a major way. The SP impacts the affinity of Env for DC-SIGN, a lectin receptor expressed on dendritic cells that is believed to play a role in mucosal transmission. Additionally, affinity for the monoclonal antibodies 17b and A32, which recognize a CD4-induced, open conformation of Env is also altered. These results demonstrate that natural variation in the SP of HIV Env can significantly impact the antigenicity of mature gp120. Thus, the SP is likely subject to antibody-mediated immune pressure.
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Affiliation(s)
- Jason Yolitz
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
- National Institutes of Health-Johns Hopkins University Graduate Partnership Program, National Institutes of Health, Bethesda, MD 20892
| | - Catherine Schwing
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Julia Chang
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Donald Van Ryk
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Fatima Nawaz
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Danlan Wei
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Claudia Cicala
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Anthony S Fauci
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
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27
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Komar AA. Unraveling co-translational protein folding: Concepts and methods. Methods 2017; 137:71-81. [PMID: 29221924 DOI: 10.1016/j.ymeth.2017.11.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/13/2017] [Indexed: 12/26/2022] Open
Abstract
Advances in techniques such as nuclear magnetic resonance spectroscopy, cryo-electron microscopy, and single-molecule and time-resolved fluorescent approaches are transforming our ability to study co-translational protein folding both in vivo in living cells and in vitro in reconstituted cell-free translation systems. These approaches provide comprehensive information on the spatial organization and dynamics of nascent polypeptide chains and the kinetics of co-translational protein folding. This information has led to an improved understanding of the process of protein folding in living cells and should allow remaining key questions in the field, such as what structures are formed within nascent chains during protein synthesis and when, to be answered. Ultimately, studies using these techniques will facilitate development of a unified concept of protein folding, a process that is essential for proper cell function and organism viability. This review describes current methods for analysis of co-translational protein folding with an emphasis on some of the recently developed techniques that allow monitoring of co-translational protein folding in real-time.
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Affiliation(s)
- Anton A Komar
- Center for Gene Regulation in Health and Disease and Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA; Department of Biochemistry and the Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH 44106, USA; Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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28
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deCamp AC, Rolland M, Edlefsen PT, Sanders-Buell E, Hall B, Magaret CA, Fiore-Gartland AJ, Juraska M, Carpp LN, Karuna ST, Bose M, LePore S, Miller S, O'Sullivan A, Poltavee K, Bai H, Dommaraju K, Zhao H, Wong K, Chen L, Ahmed H, Goodman D, Tay MZ, Gottardo R, Koup RA, Bailer R, Mascola JR, Graham BS, Roederer M, O’Connell RJ, Michael NL, Robb ML, Adams E, D’Souza P, Kublin J, Corey L, Geraghty DE, Frahm N, Tomaras GD, McElrath MJ, Frenkel L, Styrchak S, Tovanabutra S, Sobieszczyk ME, Hammer SM, Kim JH, Mullins JI, Gilbert PB. Sieve analysis of breakthrough HIV-1 sequences in HVTN 505 identifies vaccine pressure targeting the CD4 binding site of Env-gp120. PLoS One 2017; 12:e0185959. [PMID: 29149197 PMCID: PMC5693417 DOI: 10.1371/journal.pone.0185959] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 09/24/2017] [Indexed: 11/18/2022] Open
Abstract
Although the HVTN 505 DNA/recombinant adenovirus type 5 vector HIV-1 vaccine trial showed no overall efficacy, analysis of breakthrough HIV-1 sequences in participants can help determine whether vaccine-induced immune responses impacted viruses that caused infection. We analyzed 480 HIV-1 genomes sampled from 27 vaccine and 20 placebo recipients and found that intra-host HIV-1 diversity was significantly lower in vaccine recipients (P ≤ 0.04, Q-values ≤ 0.09) in Gag, Pol, Vif and envelope glycoprotein gp120 (Env-gp120). Furthermore, Env-gp120 sequences from vaccine recipients were significantly more distant from the subtype B vaccine insert than sequences from placebo recipients (P = 0.01, Q-value = 0.12). These vaccine effects were associated with signatures mapping to CD4 binding site and CD4-induced monoclonal antibody footprints. These results suggest either (i) no vaccine efficacy to block acquisition of any viral genotype but vaccine-accelerated Env evolution post-acquisition; or (ii) vaccine efficacy against HIV-1s with Env sequences closest to the vaccine insert combined with increased acquisition due to other factors, potentially including the vaccine vector.
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Affiliation(s)
- Allan C. deCamp
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail: (ACD); (MR); (PBG)
| | - Morgane Rolland
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
- * E-mail: (ACD); (MR); (PBG)
| | - Paul T. Edlefsen
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Eric Sanders-Buell
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Breana Hall
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Craig A. Magaret
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Andrew J. Fiore-Gartland
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Michal Juraska
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Lindsay N. Carpp
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Shelly T. Karuna
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Meera Bose
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Steven LePore
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Shana Miller
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Annemarie O'Sullivan
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Kultida Poltavee
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Hongjun Bai
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Kalpana Dommaraju
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Hong Zhao
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Kim Wong
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Lennie Chen
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Hasan Ahmed
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Derrick Goodman
- Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - Matthew Z. Tay
- Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - Raphael Gottardo
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Richard A. Koup
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert Bailer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John R. Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Barney S. Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mario Roederer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert J. O’Connell
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Nelson L. Michael
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Merlin L. Robb
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Elizabeth Adams
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Patricia D’Souza
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - James Kublin
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Lawrence Corey
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Daniel E. Geraghty
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Nicole Frahm
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Georgia D. Tomaras
- Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - M. Juliana McElrath
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Lisa Frenkel
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
- Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Sheila Styrchak
- Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Sodsai Tovanabutra
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Magdalena E. Sobieszczyk
- Department of Medicine, Division of Infectious Diseases, Columbia University Medical Center, New York, New York, United States of America
| | - Scott M. Hammer
- Department of Medicine, Division of Infectious Diseases, Columbia University Medical Center, New York, New York, United States of America
| | | | - James I. Mullins
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Peter B. Gilbert
- Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
- * E-mail: (ACD); (MR); (PBG)
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29
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Retroviral envelope proteins: Involvement in neuropathogenesis. J Neurol Sci 2017; 380:151-163. [DOI: 10.1016/j.jns.2017.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/23/2017] [Accepted: 07/18/2017] [Indexed: 02/07/2023]
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30
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Snapp EL, McCaul N, Quandte M, Cabartova Z, Bontjer I, Källgren C, Nilsson I, Land A, von Heijne G, Sanders RW, Braakman I. Structure and topology around the cleavage site regulate post-translational cleavage of the HIV-1 gp160 signal peptide. eLife 2017; 6:26067. [PMID: 28753126 PMCID: PMC5577925 DOI: 10.7554/elife.26067] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/26/2017] [Indexed: 12/29/2022] Open
Abstract
Like all other secretory proteins, the HIV-1 envelope glycoprotein gp160 is targeted to the endoplasmic reticulum (ER) by its signal peptide during synthesis. Proper gp160 folding in the ER requires core glycosylation, disulfide-bond formation and proline isomerization. Signal-peptide cleavage occurs only late after gp160 chain termination and is dependent on folding of the soluble subunit gp120 to a near-native conformation. We here detail the mechanism by which co-translational signal-peptide cleavage is prevented. Conserved residues from the signal peptide and residues downstream of the canonical cleavage site form an extended alpha-helix in the ER membrane, which covers the cleavage site, thus preventing cleavage. A point mutation in the signal peptide breaks the alpha helix allowing co-translational cleavage. We demonstrate that postponed cleavage of gp160 enhances functional folding of the molecule. The change to early cleavage results in decreased viral fitness compared to wild-type HIV.
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Affiliation(s)
- Erik Lee Snapp
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Nicholas McCaul
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Matthias Quandte
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Zuzana Cabartova
- National Institute of Public Health, National Reference Laboratory for Viral Hepatitis, Prague, Czech Republic
| | - Ilja Bontjer
- Department of Medical Microbiology, Laboratory of Experimental Virology, Center for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, Netherlands
| | - Carolina Källgren
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - IngMarie Nilsson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Aafke Land
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Gunnar von Heijne
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Rogier W Sanders
- Department of Medical Microbiology, Laboratory of Experimental Virology, Center for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
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31
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Behrens AJ, Seabright GE, Crispin M. Targeting Glycans of HIV Envelope Glycoproteins for Vaccine Design. CHEMICAL BIOLOGY OF GLYCOPROTEINS 2017. [DOI: 10.1039/9781782623823-00300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The surface of the envelope spike of the human immunodeficiency virus (HIV) is covered with a dense array of glycans, which is sufficient to impede the host antibody response while maintaining a window for receptor recognition. The glycan density significantly exceeds that typically observed on self glycoproteins and is sufficiently high to disrupt the maturation process of glycans, from oligomannose- to complex-type glycosylation, that normally occurs during glycoprotein transit through the secretory system. It is notable that this generates a degree of homogeneity not seen in the highly mutated protein moiety. The conserved, close glycan packing and divergences from default glycan processing give a window for immune recognition. Encouragingly, in a subset of individuals, broadly neutralizing antibodies (bNAbs) have been isolated that recognize these features and are protective in passive-transfer models. Here, we review the recent advances in our understanding of the glycan shield of HIV and outline the strategies that are being pursued to elicit glycan-binding bNAbs by vaccination.
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Affiliation(s)
- Anna-Janina Behrens
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford South Parks Road Oxford OX1 3QU UK
| | - Gemma E. Seabright
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford South Parks Road Oxford OX1 3QU UK
| | - Max Crispin
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford South Parks Road Oxford OX1 3QU UK
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32
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Heaton NS, Moshkina N, Fenouil R, Gardner TJ, Aguirre S, Shah PS, Zhao N, Manganaro L, Hultquist JF, Noel J, Sachs D, Hamilton J, Leon PE, Chawdury A, Tripathi S, Melegari C, Campisi L, Hai R, Metreveli G, Gamarnik AV, García-Sastre A, Greenbaum B, Simon V, Fernandez-Sesma A, Krogan NJ, Mulder LCF, van Bakel H, Tortorella D, Taunton J, Palese P, Marazzi I. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection. Immunity 2016; 44:46-58. [PMID: 26789921 DOI: 10.1016/j.immuni.2015.12.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022]
Abstract
Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.
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Affiliation(s)
- Nicholas S Heaton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Natasha Moshkina
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Romain Fenouil
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Thomas J Gardner
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Sebastian Aguirre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Priya S Shah
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Nan Zhao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Lara Manganaro
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Judd F Hultquist
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Justine Noel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - David Sachs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jennifer Hamilton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Paul E Leon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Amit Chawdury
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Shashank Tripathi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Camilla Melegari
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Laura Campisi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Rong Hai
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Giorgi Metreveli
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-CONICET, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Benjamin Greenbaum
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Viviana Simon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Lubbertus C F Mulder
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Domenico Tortorella
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ivan Marazzi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA.
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Ellgaard L, McCaul N, Chatsisvili A, Braakman I. Co- and Post-Translational Protein Folding in the ER. Traffic 2016; 17:615-38. [PMID: 26947578 DOI: 10.1111/tra.12392] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/26/2016] [Accepted: 03/03/2016] [Indexed: 12/19/2022]
Abstract
The biophysical rules that govern folding of small, single-domain proteins in dilute solutions are now quite well understood. The mechanisms underlying co-translational folding of multidomain and membrane-spanning proteins in complex cellular environments are often less clear. The endoplasmic reticulum (ER) produces a plethora of membrane and secretory proteins, which must fold and assemble correctly before ER exit - if these processes fail, misfolded species accumulate in the ER or are degraded. The ER differs from other cellular organelles in terms of the physicochemical environment and the variety of ER-specific protein modifications. Here, we review chaperone-assisted co- and post-translational folding and assembly in the ER and underline the influence of protein modifications on these processes. We emphasize how method development has helped advance the field by allowing researchers to monitor the progression of folding as it occurs inside living cells, while at the same time probing the intricate relationship between protein modifications during folding.
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Affiliation(s)
- Lars Ellgaard
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nicholas McCaul
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Anna Chatsisvili
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
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Shen S, Wang M, Li X, Li S, van Oers MM, Vlak JM, Braakman I, Hu Z, Deng F, Wang H. Mutational and functional analysis of N-linked glycosylation of envelope fusion protein F of Helicoverpa armigera nucleopolyhedrovirus. J Gen Virol 2016; 97:988-999. [PMID: 26769631 DOI: 10.1099/jgv.0.000404] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The envelope fusion (F) protein of baculoviruses is a heavily N-glycosylated protein that plays a significant role in the virus infection cycle. N-Linked glycosylation of virus envelope glycoprotein is important for virus envelope glycoprotein folding and its function in general. There are six predicted N-glycosylation sites in the F (HaF) protein of Helicoverpa armigera nucleopolyhedrovirus (HearNPV). The N-glycosylation site located in the F(2) subunit (N104) of HaF has been identified and functionally characterized previously (Long et al., 2007). In this study, the other five potential N-glycosylation sites located in the HaF1 subunit, namely, N293, N361, N526, N571 and N595, were analysed extensively to examine their N-glycosylation and relative importance to the function of HaF. The results showed that four of these five potential glycosylation sites in the F(1) subunit, N293, N361, N526 and N571, were N-glycosylated in F proteins of mature HearNPV budded viruses (BVs) but that N595 was not. In general, the conserved site N526 was critical to the functioning of HaF, as absence of N-glycosylation of N526 reduced the efficiency of HaF folding and trafficking, consequently decreased fusogenicity and modified the subcellular localization of HaF proteins, and thus impaired virus production and infectivity. The absence of N-glycosylation at other individual sites was found to have different effects on the fusogenicity and subcelluar distribution of HaF proteins in HzAM1 cells. In summary, N-glycosylation plays comprehensive roles in HaF function and virus infectivity, which is further discussed.
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Affiliation(s)
- Shu Shen
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina
| | - Manli Wang
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina
| | - Xin Li
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina.,Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands
| | - Shufen Li
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina
| | | | - Just M Vlak
- Laboratory of Virology, Wageningen University, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands
| | - Zhihong Hu
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina
| | - Fei Deng
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina
| | - Hualin Wang
- State Key Laboratory of Virology, and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PRChina
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35
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Cui J, Chen W, Sun J, Guo H, Madley R, Xiong Y, Pan X, Wang H, Tai AW, Weiss MA, Arvan P, Liu M. Competitive Inhibition of the Endoplasmic Reticulum Signal Peptidase by Non-cleavable Mutant Preprotein Cargos. J Biol Chem 2015; 290:28131-28140. [PMID: 26446786 DOI: 10.1074/jbc.m115.692350] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 12/30/2022] Open
Abstract
Upon translocation across the endoplasmic reticulum (ER) membrane, secretory proteins are proteolytically processed to remove their signal peptide by signal peptidase (SPase). This process is critical for subsequent folding, intracellular trafficking, and maturation of secretory proteins. Prokaryotic SPase has been shown to be a promising antibiotic target. In contrast, to date, no eukaryotic SPase inhibitors have been reported. Here we report that introducing a proline immediately following the natural signal peptide cleavage site not only blocks preprotein cleavage but also, in trans, impairs the processing and maturation of co-expressed preproteins in the ER. Specifically, we find that a variant preproinsulin, pPI-F25P, is translocated across the ER membrane, where it binds to the catalytic SPase subunit SEC11A, inhibiting SPase activity in a dose-dependent manner. Similar findings were obtained with an analogous variant of preproparathyroid hormone, demonstrating that inhibition of the SPase does not depend strictly on the sequence or structure of the downstream mature protein. We further show that inhibiting SPase in the ER impairs intracellular processing of viral polypeptides and their subsequent maturation. These observations suggest that eukaryotic SPases (including the human ortholog) are, in principle, suitable therapeutic targets for antiviral drug design.
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Affiliation(s)
- Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China,; Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Wei Chen
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105,; Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - Jinhong Sun
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Huan Guo
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Rachel Madley
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Yi Xiong
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Xingyi Pan
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Hongliang Wang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Andrew W Tai
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Michael A Weiss
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106.
| | - Peter Arvan
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China,; Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
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36
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Veit M, Matczuk AK, Sinhadri BC, Krause E, Thaa B. Membrane proteins of arterivirus particles: structure, topology, processing and function. Virus Res 2014; 194:16-36. [PMID: 25278143 PMCID: PMC7172906 DOI: 10.1016/j.virusres.2014.09.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/20/2014] [Accepted: 09/23/2014] [Indexed: 01/01/2023]
Abstract
Arteriviruses are important pathogens in veterinary medicine. We review the structure and processing of their membrane proteins. Some features are unique from a cell biological point of view. New data on this topic are also presented. We speculate on the role of the membrane proteins during virus entry and budding.
Arteriviruses, such as equine arteritis virus (EAV) and porcine reproductive and respiratory syndrome virus (PRRSV), are important pathogens in veterinary medicine. Despite their limited genome size, arterivirus particles contain a multitude of membrane proteins, the Gp5/M and the Gp2/3/4 complex, the small and hydrophobic E protein and the ORF5a protein. Their function during virus entry and budding is understood only incompletely. We summarize current knowledge of their primary structure, membrane topology, (co-translational) processing and intracellular targeting to membranes of the exocytic pathway, which are the budding site. We profoundly describe experimental data that led to widely believed conceptions about the function of these proteins and also report new results about processing steps for each glycoprotein. Further, we depict the location and characteristics of epitopes in the membrane proteins since the late appearance of neutralizing antibodies may lead to persistence, a characteristic hallmark of arterivirus infection. Some molecular features of the arteriviral proteins are rare or even unique from a cell biological point of view, particularly the prevention of signal peptide cleavage by co-translational glycosylation, discovered in EAV-Gp3, and the efficient use of overlapping sequons for glycosylation. This article reviews the molecular mechanisms of these cellular processes. Based on this, we present hypotheses on the structure and variability of arteriviral membrane proteins and their role during virus entry and budding.
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Affiliation(s)
- Michael Veit
- Institut für Virologie, Veterinärmedizin, Freie Universität Berlin, Germany.
| | | | | | - Eberhard Krause
- Leibniz Institute of Molecular Pharmacology (FMP), Berlin, Germany
| | - Bastian Thaa
- Institut für Virologie, Veterinärmedizin, Freie Universität Berlin, Germany
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Mathys L, François KO, Quandte M, Braakman I, Balzarini J. Deletion of the highly conserved N-glycan at Asn260 of HIV-1 gp120 affects folding and lysosomal degradation of gp120, and results in loss of viral infectivity. PLoS One 2014; 9:e101181. [PMID: 24967714 PMCID: PMC4072736 DOI: 10.1371/journal.pone.0101181] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/03/2014] [Indexed: 12/16/2022] Open
Abstract
N-linked glycans covering the surface of the HIV-1 glycoprotein gp120 are of major importance for the correct folding of this glycoprotein. Of the, on average, 24 N-linked glycans present on gp120, the glycan at Asn260 was reported to be essential for the correct expression of gp120 and gp41 in the virus particle and deletion of the N260 glycan in gp120 heavily compromised virus infectivity. We show here that gp160 containing the N260Q mutation reaches the Golgi apparatus during biosynthesis. Using pulse-chase experiments with [35S] methionine/cysteine, we show that oxidative folding was slightly delayed in case of mutant N260Q gp160 and that CD4 binding was markedly compromised compared to wild-type gp160. In the search of compensatory mutations, we found a mutation in the V1/V2 loop of gp120 (S128N) that could partially restore the infectivity of mutant N260Q gp120 virus. However, the mutation S128N did not enhance any of the above-mentioned processes so its underlying compensatory mechanism must be a conformational effect that does not affect CD4 binding per se. Finally, we show that mutant N260Q gp160 was cleaved to gp120 and gp41 to a much lower extent than wild-type gp160, and that it was subject of lysosomal degradation to a higher extent than wild-type gp160 showing a prominent role of this process in the breakdown of N260-glycan-deleted gp160, which could not be counteracted by the S128N mutation. Moreover, at least part of the wild-type or mutant gp160 that is normally targeted for lysosomal degradation reached a conformation that enabled CD4 binding.
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Affiliation(s)
- Leen Mathys
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | | | - Matthias Quandte
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Jan Balzarini
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
- * E-mail:
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38
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Irvine AG, Wallis AK, Sanghera N, Rowe ML, Ruddock LW, Howard MJ, Williamson RA, Blindauer CA, Freedman RB. Protein disulfide-isomerase interacts with a substrate protein at all stages along its folding pathway. PLoS One 2014; 9:e82511. [PMID: 24465374 PMCID: PMC3896340 DOI: 10.1371/journal.pone.0082511] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 10/25/2013] [Indexed: 02/06/2023] Open
Abstract
In contrast to molecular chaperones that couple protein folding to ATP hydrolysis, protein disulfide-isomerase (PDI) catalyzes protein folding coupled to formation of disulfide bonds (oxidative folding). However, we do not know how PDI distinguishes folded, partly-folded and unfolded protein substrates. As a model intermediate in an oxidative folding pathway, we prepared a two-disulfide mutant of basic pancreatic trypsin inhibitor (BPTI) and showed by NMR that it is partly-folded and highly dynamic. NMR studies show that it binds to PDI at the same site that binds peptide ligands, with rapid binding and dissociation kinetics; surface plasmon resonance shows its interaction with PDI has a Kd of ca. 10−5 M. For comparison, we characterized the interactions of PDI with native BPTI and fully-unfolded BPTI. Interestingly, PDI does bind native BPTI, but binding is quantitatively weaker than with partly-folded and unfolded BPTI. Hence PDI recognizes and binds substrates via permanently or transiently unfolded regions. This is the first study of PDI's interaction with a partly-folded protein, and the first to analyze this folding catalyst's changing interactions with substrates along an oxidative folding pathway. We have identified key features that make PDI an effective catalyst of oxidative protein folding – differential affinity, rapid ligand exchange and conformational flexibility.
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Affiliation(s)
- Alistair G. Irvine
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Department of Chemistry, University of Warwick, Coventry, United Kingdom
| | - A. Katrine Wallis
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Narinder Sanghera
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Michelle L. Rowe
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | | | - Mark J. Howard
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | | | | | - Robert B. Freedman
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail:
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Identification of a cluster of HIV-1 controllers infected with low replicating viruses. PLoS One 2013; 8:e77663. [PMID: 24204910 PMCID: PMC3813686 DOI: 10.1371/journal.pone.0077663] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/12/2013] [Indexed: 11/19/2022] Open
Abstract
Long term non-progressor patients (LTNPs) are characterized by the natural control of HIV-1 infection. This control is related to host genetic, immunological and virological factors. In this work, phylogenetic analysis of the proviral nucleotide sequences in env gene from a Spanish HIV-1 LTNPs cohort identified a cluster of 6 HIV-1 controllers infected with closely-related viruses. The patients of the cluster showed common clinical and epidemiological features: drug user practices, infection in the same city (Madrid, Spain) and at the same time (late 70's-early 80's). All cluster patients displayed distinct host alleles associated with HIV control. Analysis of the virus envelope nucleotide sequences showed ancestral characteristic, lack of evolution and presence of rare amino-acids. Biological characterization of recombinant viruses with the envelope proteins from the cluster viruses showed very low replicative capacity in TZMbl and U87-CD4/CCR5 cells. The lack of clinical progression in the viral cluster patients with distinct combinations of protective host genotypes, but infected by low replicating viruses, indicate the important role of the virus in the non-progressor phenotype in these patients.
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40
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Abstract
In this article, we will cover the folding of proteins in the lumen of the endoplasmic reticulum (ER), including the role of three types of covalent modifications: signal peptide removal, N-linked glycosylation, and disulfide bond formation, as well as the function and importance of resident ER folding factors. These folding factors consist of classical chaperones and their cochaperones, the carbohydrate-binding chaperones, and the folding catalysts of the PDI and proline cis-trans isomerase families. We will conclude with the perspective of the folding protein: a comparison of characteristics and folding and exit rates for proteins that travel through the ER as clients of the ER machinery.
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Affiliation(s)
- Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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41
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Subtle alteration of residues including N-linked glycans in V2 loop modulate HIV-1 neutralization by PG9 and PG16 monoclonal antibodies. Virology 2012; 426:34-41. [PMID: 22314018 DOI: 10.1016/j.virol.2012.01.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 12/27/2011] [Accepted: 01/13/2012] [Indexed: 11/23/2022]
Abstract
Recent discovery of several potent and broadly neutralizing monoclonal antibodies (MAbs) (such as PG9 and PG16) to HIV-1 provided clues on newer vaccine targets. In the present study, we found an env clone obtained from a slow progressor showing significant resistance to PG9 and PG16 MAbs in sharp contrast to other contemporaneous autologous env clones. By constructing chimeric envelopes and specific substitutions we found that both loop length and spatial orientation of glycan residues in addition to the net charge of the β sheet C region that directly binds to PG9 CDRH3 within V2 loop significantly modulated HIV-1 sensitivity to PG9 and PG16 MAbs. Similar observation were made with several other Envs which varied in length, glycan content and net charge in PG9 contacting complementary region in V2 loop. Our data indicated that subtle change within V2 loop alone modulates exposition of quaternary epitopes that are targets of PG9/PG16 MAbs.
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42
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HIV-1 virus-like particles bearing pure env trimers expose neutralizing epitopes but occlude nonneutralizing epitopes. J Virol 2012; 86:3574-87. [PMID: 22301141 DOI: 10.1128/jvi.06938-11] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hypothetically, since native HIV-1 Env trimers are exclusively recognized by neutralizing antibodies, they might induce the neutralizing antibodies in a vaccine setting. This idea has not been evaluated due to the difficulty of separating trimers from nonfunctional Env (uncleaved gp160 and gp41 stumps). The latter are immunodominant and induce nonneutralizing antibodies. We previously showed that nonfunctional Env can be selectively cleared from virus-like particle (VLP) surfaces by enzyme digests (E. T. Crooks, T. Tong(,) K. Osawa, and J. M. Binley, J.Virol. 85:5825, 2011). Here, we investigated the effects of these digests on the antigenicity of VLPs and their sensitivity to neutralization. Before digestion, WT VLPs (bearing wild-type Env) and UNC VLPs (bearing uncleaved gp160) were recognized by various Env-specific monoclonal antibodies (MAbs), irrespective of their neutralizing activity, a result which is consistent with the presence of nonfunctional Env. After digestion, only neutralizing MAbs recognized WT VLPs, consistent with selective removal of nonfunctional Env (i.e., "trimer VLPs"). Digests eliminated the binding of all MAbs to UNC VLPs, again consistent with removal of nonfunctional Env. An exception was MAb 2F5, which weakly bound to digested UNC VLPs and bald VLPs (bearing no Env), perhaps due to lipid cross-reactivity. Trimer VLPs were infectious, and their neutralization sensitivity was largely comparable to that of undigested WT VLPs. However, they were ∼100-fold more sensitive to the MAbs 4E10 and Z13e1, suggesting increased exposure of the gp41 base. Importantly, a scatterplot analysis revealed a strong correlation between MAb binding and neutralization of trimer VLPs. This suggests that trimer VLPs bear essentially pure native trimer that should allow its unfettered evaluation in a vaccine setting.
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Wilen CB, Tilton JC, Doms RW. Molecular mechanisms of HIV entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 726:223-42. [PMID: 22297516 DOI: 10.1007/978-1-4614-0980-9_10] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Human immunodeficiency virus (HIV) entry is a complex and intricate process that facilitates delivery of the viral genome to the host cell. The only viral surface protein, Envelope (Env), is composed of a trimer of gp120 and gp41 heterodimers. It is essentially a fusion machine cloaked in a shroud of carbohydrate structures and variable loops of amino acids that enable it to evade the humoral immune response. For entry to occur gp120 sequentially engages the host protein CD4 and then one of two chemokine coreceptors, either CCR5 or CXCR4. CD4 binding facilitates exposure and formation of the coreceptor-binding site, and coreceptor binding then triggers the membrane fusion machinery in the gp41 subunit. Our understanding of HIV entry has led to the development of successful small molecule inhibitors for the clinical treatment of HIV infection as well as insights into viral tropism and pathogenesis.
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Affiliation(s)
- Craig B Wilen
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Abstract
Analysis of the human genome reveals that approximately a third of all open reading frames code for proteins that enter the endoplasmic reticulum (ER), demonstrating the importance of this organelle for global protein maturation. The path taken by a polypeptide through the secretory pathway starts with its translocation across or into the ER membrane. It then must fold and be modified correctly in the ER before being transported via the Golgi apparatus to the cell surface or another destination. Being physically segregated from the cytosol means that the ER lumen has a distinct folding environment. It contains much of the machinery for fulfilling the task of protein production, including complex pathways for folding, assembly, modification, quality control, and recycling. Importantly, the compartmentalization means that several modifications that do not occur in the cytosol, such as glycosylation and extensive disulfide bond formation, can occur to secreted proteins to enhance their stability before their exposure to the extracellular milieu. How these various machineries interact during the normal pathway of folding and protein secretion is the subject of this review.
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Affiliation(s)
- Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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Gnanakaran S, Bhattacharya T, Daniels M, Keele BF, Hraber PT, Lapedes AS, Shen T, Gaschen B, Krishnamoorthy M, Li H, Decker JM, Salazar-Gonzalez JF, Wang S, Jiang C, Gao F, Swanstrom R, Anderson JA, Ping LH, Cohen MS, Markowitz M, Goepfert PA, Saag MS, Eron JJ, Hicks CB, Blattner WA, Tomaras GD, Asmal M, Letvin NL, Gilbert PB, DeCamp AC, Magaret CA, Schief WR, Ban YEA, Zhang M, Soderberg KA, Sodroski JG, Haynes BF, Shaw GM, Hahn BH, Korber B. Recurrent signature patterns in HIV-1 B clade envelope glycoproteins associated with either early or chronic infections. PLoS Pathog 2011; 7:e1002209. [PMID: 21980282 PMCID: PMC3182927 DOI: 10.1371/journal.ppat.1002209] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 06/26/2011] [Indexed: 12/15/2022] Open
Abstract
Here we have identified HIV-1 B clade Envelope (Env) amino acid signatures from early in infection that may be favored at transmission, as well as patterns of recurrent mutation in chronic infection that may reflect common pathways of immune evasion. To accomplish this, we compared thousands of sequences derived by single genome amplification from several hundred individuals that were sampled either early in infection or were chronically infected. Samples were divided at the outset into hypothesis-forming and validation sets, and we used phylogenetically corrected statistical strategies to identify signatures, systematically scanning all of Env. Signatures included single amino acids, glycosylation motifs, and multi-site patterns based on functional or structural groupings of amino acids. We identified signatures near the CCR5 co-receptor-binding region, near the CD4 binding site, and in the signal peptide and cytoplasmic domain, which may influence Env expression and processing. Two signatures patterns associated with transmission were particularly interesting. The first was the most statistically robust signature, located in position 12 in the signal peptide. The second was the loss of an N-linked glycosylation site at positions 413-415; the presence of this site has been recently found to be associated with escape from potent and broad neutralizing antibodies, consistent with enabling a common pathway for immune escape during chronic infection. Its recurrent loss in early infection suggests it may impact fitness at the time of transmission or during early viral expansion. The signature patterns we identified implicate Env expression levels in selection at viral transmission or in early expansion, and suggest that immune evasion patterns that recur in many individuals during chronic infection when antibodies are present can be selected against when the infection is being established prior to the adaptive immune response.
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Affiliation(s)
- S. Gnanakaran
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Tanmoy Bhattacharya
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Santa Fe Institute, Santa Fe, New Mexico, United States of America
| | - Marcus Daniels
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Brandon F. Keele
- SAIC-Frederick, National Cancer Institute, Frederick, Maryland, United States of America
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Peter T. Hraber
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Alan S. Lapedes
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Tongye Shen
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Center for Molecular Biophysics and Department of Biochemistry, Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Brian Gaschen
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Mohan Krishnamoorthy
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Hui Li
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Julie M. Decker
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jesus F. Salazar-Gonzalez
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Shuyi Wang
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Chunlai Jiang
- National Engineering Laboratory of AIDS Vaccine School of Life Science, Jilin University, Changchun, China
- Duke University Medical Center, the Departments of Medicine and Surgery, and the Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - Feng Gao
- Duke University Medical Center, the Departments of Medicine and Surgery, and the Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - Ronald Swanstrom
- Department of Biochemistry and Biophysics and the Division of Infectious Diseases Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jeffrey A. Anderson
- Department of Biochemistry and Biophysics and the Division of Infectious Diseases Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Li-Hua Ping
- Department of Biochemistry and Biophysics and the Division of Infectious Diseases Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Myron S. Cohen
- Department of Biochemistry and Biophysics and the Division of Infectious Diseases Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Martin Markowitz
- Aaron Diamond AIDS Research Center, an affiliate of the Rockefeller University, New York, New York, United States of America
| | - Paul A. Goepfert
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Michael S. Saag
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Joseph J. Eron
- Department of Biochemistry and Biophysics and the Division of Infectious Diseases Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Charles B. Hicks
- Duke University Medical Center, the Departments of Medicine and Surgery, and the Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - William A. Blattner
- Institute of Human Virology, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Georgia D. Tomaras
- Duke University Medical Center, the Departments of Medicine and Surgery, and the Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - Mohammed Asmal
- Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Norman L. Letvin
- Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Division of Viral Pathogenesis, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter B. Gilbert
- Vaccine Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United State of America
| | - Allan C. DeCamp
- Vaccine Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United State of America
| | - Craig A. Magaret
- Vaccine Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United State of America
| | - William R. Schief
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Yih-En Andrew Ban
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Arzeda Corporation, Seattle, Washington, United States of America
| | - Ming Zhang
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia, United States of America
| | - Kelly A. Soderberg
- Duke University Medical Center, the Departments of Medicine and Surgery, and the Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - Joseph G. Sodroski
- Dana-Farber Cancer Institute, Department of Cancer Immunology and AIDS, Boston, Massachusetts, United States of America
| | - Barton F. Haynes
- Duke University Medical Center, the Departments of Medicine and Surgery, and the Duke Human Vaccine Institute, Duke University, Durham, North Carolina, United States of America
| | - George M. Shaw
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Beatrice H. Hahn
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Bette Korber
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Santa Fe Institute, Santa Fe, New Mexico, United States of America
- * E-mail:
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Asmal M, Hellmann I, Liu W, Keele BF, Perelson AS, Bhattacharya T, Gnanakaran S, Daniels M, Haynes BF, Korber BT, Hahn BH, Shaw GM, Letvin NL. A signature in HIV-1 envelope leader peptide associated with transition from acute to chronic infection impacts envelope processing and infectivity. PLoS One 2011; 6:e23673. [PMID: 21876761 PMCID: PMC3158090 DOI: 10.1371/journal.pone.0023673] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/22/2011] [Indexed: 11/21/2022] Open
Abstract
Mucosal transmission of the human immunodeficiency virus (HIV) results in a bottleneck in viral genetic diversity. Gnanakaran and colleagues used a computational strategy to identify signature amino acids at particular positions in Envelope that were associated either with transmitted sequences sampled very early in infection, or sequences sampled during chronic infection. Among the strongest signatures observed was an enrichment for the stable presence of histidine at position 12 at transmission and in early infection, and a recurrent loss of histidine at position 12 in chronic infection. This amino acid lies within the leader peptide of Envelope, a region of the protein that has been shown to influence envelope glycoprotein expression and virion infectivity. We show a strong association between a positively charged amino acid like histidine at position 12 in transmitted/founder viruses with more efficient trafficking of the nascent envelope polypeptide to the endoplasmic reticulum and higher steady-state glycoprotein expression compared to viruses that have a non-basic position 12 residue, a substitution that was enriched among viruses sampled from chronically infected individuals. When expressed in the context of other viral proteins, transmitted envelopes with a basic amino acid position 12 were incorporated at higher density into the virus and exhibited higher infectious titers than did non-signature envelopes. These results support the potential utility of using a computational approach to examine large viral sequence data sets for functional signatures and indicate the importance of Envelope expression levels for efficient HIV transmission.
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Affiliation(s)
- Mohammed Asmal
- Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.
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Co-translational function of Cosmc, core 1 synthase specific molecular chaperone, revealed by a cell-free translation system. FEBS Lett 2011; 585:1276-80. [PMID: 21496458 DOI: 10.1016/j.febslet.2011.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 03/25/2011] [Accepted: 04/01/2011] [Indexed: 01/27/2023]
Abstract
The core 1 structure of the mucin type O-glycan is synthesized by core 1 β1,3-galactosyltransferase (C1GalT). Core 1 synthase specific molecular chaperone (Cosmc), a molecular chaperone specific for C1GalT, is essential for the expression of functional C1GalT in mammalian cells. In this study, we have established a procedure for detecting the chaperone activity of Cosmc by using a wheat germ cell-free translation system. Active C1GalT was expressed following simultaneous translation with Cosmc or translation in the presence of recombinant Cosmc protein. Moreover, we show that recombinant Cosmc must be present during the translation of C1GalT, as it is ineffective when added after translation. These results indicate that Cosmc mediates the co-translational activation of C1GalT and that it may prevent the unfavorable aggregation of C1GalT.
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Enzyme digests eliminate nonfunctional Env from HIV-1 particle surfaces, leaving native Env trimers intact and viral infectivity unaffected. J Virol 2011; 85:5825-39. [PMID: 21471242 DOI: 10.1128/jvi.00154-11] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1 viruses and virus-like particles (VLPs) bear nonnative "junk" forms of envelope (Env) glycoprotein that may undermine the development of antibody responses against functional gp120/gp41 trimers, thereby blunting the ability of particles to elicit neutralizing antibodies. Here, we sought to better understand the nature of junk Env with a view to devising strategies for its removal. Initial studies revealed that native trimers were surprisingly stable in the face of harsh conditions, suggesting that junk Env is unlikely to arise by trimer dissociation or gp120 shedding. Furthermore, the limited gp120 shedding that occurs immediately after synthesis of primary HIV-1 isolate Envs is not caused by aberrant cleavage at the tandem gp120/gp41 cleavage sites, which were found to cleave in a codependent manner. A major VLP contaminant was found to consist of an early, monomeric form of gp160 that is glycosylated in the endoplasmic reticulum (gp160ER) and then bypasses protein maturation and traffics directly into particles. gp160ER was found to bind two copies of monoclonal antibody (MAb) 2G12, consistent with its exclusively high-mannose glycan profile. These findings prompted us to evaluate enzyme digests as a way to remove aberrant Env. Remarkably, sequential glycosidase-protease digests led to a complete or near-complete removal of junk Env from many viral strains, leaving trimers and viral infectivity largely intact. "Trimer VLPs" may be useful neutralizing antibody immunogens.
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Wallis AK, Freedman RB. Assisting Oxidative Protein Folding: How Do Protein Disulphide-Isomerases Couple Conformational and Chemical Processes in Protein Folding? Top Curr Chem (Cham) 2011; 328:1-34. [DOI: 10.1007/128_2011_171] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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50
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Rutkevich LA, Cohen-Doyle MF, Brockmeier U, Williams DB. Functional relationship between protein disulfide isomerase family members during the oxidative folding of human secretory proteins. Mol Biol Cell 2010; 21:3093-105. [PMID: 20660153 PMCID: PMC2938376 DOI: 10.1091/mbc.e10-04-0356] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
To examine the relationship between protein disulfide isomerase family members within the mammalian endoplasmic reticulum, PDI, ERp57, ERp72, and P5 were depleted with high efficiency in human hepatoma cells, either singly or in combination. The impact was assessed on the oxidative folding of several well-characterized secretory proteins. We show that PDI plays a predominant role in oxidative folding because its depletion delayed disulfide formation in all secretory proteins tested. However, the phenotype was surprisingly modest suggesting that other family members are able to compensate for PDI depletion, albeit with reduced efficacy. ERp57 also exhibited broad specificity, overlapping with that of PDI, but with preference for glycosylated substrates. Depletion of both PDI and ERp57 revealed that some substrates require both enzymes for optimal folding and, furthermore, led to generalized protein misfolding, impaired export from the ER, and degradation. In contrast, depletion of ERp72 or P5, either alone or in combination with PDI or ERp57 had minimal impact, revealing a narrow substrate specificity for ERp72 and no detectable role for P5 in oxidative protein folding.
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Affiliation(s)
- Lori A Rutkevich
- Department of Biochemistry, University of Toronto, Toronto, Canada
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