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Shao W, Chen X, Samulski RJ, Hirsch ML, Li C. Inhibition of antigen presentation during AAV gene therapy using virus peptides. Hum Mol Genet 2019; 27:601-613. [PMID: 29272432 DOI: 10.1093/hmg/ddx427] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 12/12/2017] [Indexed: 11/14/2022] Open
Abstract
The clinical trial using adeno-associated virus (AAV) vector delivery of mini-dystrophin in patients with Duchenne Muscular Dystrophy (DMD) demonstrated a cytotoxic lymphocyte (CTL) response targeting the transgene product. These mini-dystrophin-specific T-cells have the potential to clear all transduced muscle, presenting the general gene therapy concern of overcoming the CTL response to foreign proteins that provide therapeutic benefit. In this study, we exploited a natural immunosuppression strategy employed by some viruses that results in CTL evasion only in transduced cells. After transfection of the plasmids encoding viral peptides and ovalbumin, which includes the immune-domain epitope SIINFEKL, several viral small peptides (ICP47 and US6) inhibited the SIINFEKL peptide presentation. A single AAV vector genome that consisted of either transgene AAT fused with SIINFEKL epitope and, separately, ICP47 expressed from different promoters or a single fusion protein with ICP47 linked by a furin cleavage peptide (AATOVA-ICP47) decreased antigen presentation. Compared with AAV/AATOVA in which decreased AAT expression was observed at late time points, persistent transgene expression was obtained after systemic administration of AAV/AATOVA-ICP47 vectors in mice. We extended this strategy to DMD gene therapy. After administration of AAV vector encoding human mini-dystrophin fusion protein with ICP47 into mdx mice, a lower mini-dystrophin-specific CTL response was induced. Importantly, the ICP47 fusion to mini-dystrophin inhibited CTLs mediated cytotoxicity. Although demonstrated herein using AAT and mini-dystrophin transgenes in an AAV context, the collective results have implications for all gene therapy applications resulting in foreign peptides by immune suppression in only genetically modified cells.
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Affiliation(s)
- Wenwei Shao
- Gene Therapy Center, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Xiaojing Chen
- Gene Therapy Center, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Richard J Samulski
- Gene Therapy Center, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Matthew L Hirsch
- Gene Therapy Center, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Chengwen Li
- Gene Therapy Center, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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2
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Abstract
HIV-1 Nef binds to the cytoplasmic region of HLA-A and HLA-B and downregulates these molecules from the surface of virus-infected cells, thus evading immune detection by CD8+ T cells. Polymorphic residues within the HLA cytoplasmic region may affect Nef’s downregulation activity. However, the effects of HLA polymorphisms on recognition by primary Nef isolates remain elusive, as do the specific Nef regions responsible for downregulation of HLA-A versus HLA-B. Here, we examined 46 Nef clones isolated from chronically HIV-1 subtype B-infected subjects for their ability to downregulate various HLA-A, HLA-B, and HLA-C molecules on the surface of virus-infected cells. Overall, HLA-B exhibited greater resistance to Nef-mediated downregulation than HLA-A, regardless of the cell type examined. As expected, no Nef clone downregulated HLA-C. Importantly, the differential abilities of patient-derived Nef clones to downregulate HLA-A and HLA-B correlated inversely with the sensitivities of HIV-infected target cells to recognition by effector cells expressing an HIV-1 Gag-specific T cell receptor. Nef codon function analysis implicated amino acid variation at position 202 (Nef-202) in differentially affecting the ability to downregulate HLA-A and HLA-B, an observation that was subsequently confirmed by experiments using Nef mutants constructed by site-directed mutagenesis. The in silico and mutagenesis analyses further suggested that Nef-202 may interact with the C-terminal Cys-Lys-Val residues of HLA-A, which are absent in HLA-B. Taken together, the results show that natural polymorphisms within Nef modulate its interaction with natural polymorphisms in the HLA cytoplasmic tails, thereby affecting the efficiency of HLA downregulation and consequent recognition by HIV-specific T cells. These results thus extend our understanding of this complex pathway of retroviral immune evasion. Recognition of genetically diverse pathogens by the adaptive immune system represents a primary strategy for host defense; however, pathogens such as HIV-1 can evade these responses to achieve persistent infection. The HIV-1 nef gene and the HLA class I locus rank among the most diverse genes of virus and host, respectively. The HIV-1 Nef protein interacts with the cytoplasmic region of HLA-A and HLA-B and downregulates these molecules to evade cellular immunity. By combining molecular, genetic, and in silico analyses, we demonstrate that patient-derived Nef clones downregulate HLA-A more effectively than HLA-B molecules. This in turn modulates the ability of HIV-specific T cells to recognize HIV-infected cells. We also identify a naturally polymorphic site at Nef codon 202 and HLA cytoplasmic motifs (GG314,315 and CKV339–341) that contribute to differential HLA downregulation by Nef. Our results highlight new interactions between HIV-1 and the human immune system that may contribute to pathogenesis.
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Equine herpesvirus type 4 UL56 and UL49.5 proteins downregulate cell surface major histocompatibility complex class I expression independently of each other. J Virol 2012; 86:8059-71. [PMID: 22623773 DOI: 10.1128/jvi.00891-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Major histocompatibility complex class I (MHC-I) molecules are critically important in the host defense against various pathogens through presentation of viral peptides to cytotoxic T lymphocytes (CTLs), a process resulting in the destruction of virus-infected cells. Herpesviruses interfere with CTL-mediated elimination of infected cells by various mechanisms, including inhibition of peptide transport and loading, perturbation of MHC-I trafficking, and rerouting and proteolysis of cell surface MHC-I. In this study, we show that equine herpesvirus type 4 (EHV-4) modulates MHC-I cell surface expression through two different mechanisms. First, EHV-4 can lead to a significant downregulation of MHC-I expression at the cell surface through the product of ORF1, a protein expressed with early kinetics from a gene that is homologous to herpes simplex virus 1 UL56. The EHV-4 UL56 protein reduces cell surface MHC-I as early as 4 h after infection. Second, EHV-4 can interfere with MHC-I antigen presentation, starting at 6 h after infection, by inhibition of the transporter associated with antigen processing (TAP) through its UL49.5 protein. Although pUL49.5 has no immediate effect on overall surface MHC-I levels in infected cells, it blocks the supply of antigenic peptides to the endoplasmic reticulum (ER) and transport of peptide-loaded MHC-I to the cell surface. Taken together, our results show that EHV-4 encodes at least two viral immune evasion proteins: pUL56 reduces MHC-I molecules on the cell surface at early times after infection, and pUL49.5 interferes with MHC-I antigen presentation by blocking peptide transport in the ER.
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Verweij MC, Ressing ME, Knetsch W, Quinten E, Halenius A, van Bel N, Hengel H, Drijfhout JW, van Hall T, Wiertz EJHJ. Inhibition of mouse TAP by immune evasion molecules encoded by non-murine herpesviruses. Mol Immunol 2011; 48:835-45. [PMID: 21292324 DOI: 10.1016/j.molimm.2010.12.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 12/09/2010] [Accepted: 12/10/2010] [Indexed: 12/26/2022]
Abstract
Herpesviruses escape elimination by cytotoxic T lymphocytes through specific interference with the antigen-presenting function of MHC class I (MHC I) molecules. The transporter associated with antigen processing (TAP) forms a bottleneck in the MHC I antigen presentation pathway. The fact that multiple viruses, especially herpesviruses, encode molecules blocking TAP function is a case in point. The action of these viral immuno evasins is usually potent and very specific, making these proteins valuable tools for studying the cell biology of antigen presentation, including alternative antigen processing pathways. Yet, no dedicated TAP inhibitor has been described for any of the mouse herpesviruses. To permit the use of immuno evasins derived from non-mouse herpesviruses in mouse models, we assessed the cross-species activity of four TAP inhibitors and one tapasin inhibitor in the context of three different mouse haplotypes, H-2(b), H-2(d), and H-2(k). Two of the four TAP inhibitors, the bovine herpesvirus 1-encoded UL49.5 and the human cytomegalovirus (HCMV)-encoded US6 protein, potently inhibited mouse TAP. ICP47 and BNLF2a, encoded by herpes simplexvirus 1 and Epstein-Barr virus, respectively, failed to inhibit TAP in all mouse cells tested. Previous work, however, demonstrated that US6 did not cross the mouse species barrier. We now show that substitution of the cysteine residue at position 108 was responsible for this lack of activity. The HCMV-encoded tapasin inhibitor US3 efficiently downregulated H-2(d) molecules on 3T3 cells, but not in other cell lines tested. Finally, we show that synthetic peptides comprising the functional domain of US6 can be exploited as a versatile TAP inhibitor. In conclusion, a complete overview is presented of the applicability of herpesvirus-encoded TAP and tapasin inhibitors in mouse cells of different genetic background.
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Affiliation(s)
- Marieke C Verweij
- Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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5
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Abstract
Herpesviruses have evolved several effective strategies to counter the host immune response. Chief among these is inhibition of the host MHC class I antigen processing and presentation pathway, thereby reducing the presentation of virus-derived epitopes on the surface of the infected cell. This review summarizes the mechanisms used by herpesviruses to achieve this goal, including shut-down of MHC class I molecule synthesis, blockage of proteasome-mediated peptide generation and prevention of TAP-mediated peptide transport. Furthermore, herpesvirus proteins can retain MHC class I molecules in the endoplasmic reticulum, or direct their retrograde translocation from the endoplasmic reticulum or endocytosis from the plasma membrane, with subsequent degradation. The resulting down-regulation of cell surface MHC class I peptide complexes thwarts the ability of cytotoxic T lymphocytes to recognize and eliminate virus-infected cells. The subversion of the natural killer cell response by herpesvirus proteins and microRNAs is also discussed.
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Affiliation(s)
- Bryan D Griffin
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Rimmelzwaan GF, Kreijtz JHCM, Bodewes R, Fouchier RAM, Osterhaus ADME. Influenza virus CTL epitopes, remarkably conserved and remarkably variable. Vaccine 2009; 27:6363-5. [PMID: 19840674 DOI: 10.1016/j.vaccine.2009.01.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 01/06/2009] [Accepted: 01/08/2009] [Indexed: 01/05/2023]
Abstract
Virus-specific cytotoxic T lymphocytes (CTL) contribute to the control of virus infections including those caused by influenza viruses. Especially under circumstances when antibodies induced by previous infection or vaccination fail to recognize and neutralize the virus adequately, CTL are important and contribute to protective immunity. During epidemic outbreaks caused by antigenic drift variants and during pandemic outbreaks of influenza, humoral immunity against influenza viruses is inadequate. Under these circumstances, pre-existing CTL directed to the relatively conserved internal proteins of the virus may provide cross-protective immunity. Indeed, most of the known human influenza virus CTL epitopes are conserved. However, during the evolution of influenza A/H3N2 viruses, the most important cause of seasonal influenza outbreaks, variation in CTL epitopes has been observed. The observed amino acid substitutions affected recognition by virus-specific CTL and the human virus-specific CTL response in vitro. Examples of variable epitopes and their HLA restrictions are: NP(383-391)/HLA-B*2705, NP(380-388)/HLA-B*0801, NP(418-426)/HLA-B*3501, NP(251-259)/HLA-B*4002, NP(103-111)/HLA-B*1503. In some cases amino acid substitutions occurred at anchor residues and in other cases at T cell receptor contact residues. It is of special interest that the R384G substitution in the NP(383-391) epitope was detrimental to virus fitness and was only tolerated in the presence of multiple functionally compensating co-mutations. In contrast, other epitopes, like the HLA-A*0201 restricted epitope from the matrix protein, M1(58-66), are highly conserved despite their immunodominant nature and the high prevalence of HLA-A*0201 in the population. A mutational analysis of this epitope indicated that it is under functional constraints. Also in influenza A viruses of other subtypes, including H5N1, the M1(58-66) is highly conserved.
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Affiliation(s)
- Guus F Rimmelzwaan
- Department of Virology, Erasmus Medical Center, Rotterdam, The Netherlands.
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7
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MHC class I antigen presentation: learning from viral evasion strategies. Nat Rev Immunol 2009; 9:503-13. [PMID: 19498380 DOI: 10.1038/nri2575] [Citation(s) in RCA: 313] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cell surface display of peptides by MHC class I molecules to lymphocytes provides the host with an important surveillance mechanism to protect against invading pathogens. However, in turn, viruses have evolved elegant strategies to inhibit various stages of the MHC class I antigen presentation pathway and prevent the display of viral peptides. This Review highlights how the elucidation of mechanisms of viral immune evasion is important for advancing our understanding of virus-host interactions and can further our knowledge of the MHC class I presentation pathway as well as other cellular pathways.
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8
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E3 ubiquitin ligases for MHC molecules. Curr Opin Immunol 2009; 21:78-83. [DOI: 10.1016/j.coi.2009.01.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 01/15/2009] [Indexed: 12/20/2022]
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9
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Wang X, Herr RA, Hansen T. Viral and cellular MARCH ubiquitin ligases and cancer. Semin Cancer Biol 2008; 18:441-50. [PMID: 18948196 DOI: 10.1016/j.semcancer.2008.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 09/26/2008] [Indexed: 11/18/2022]
Abstract
Covalent conjugation of proteins with ubiquitin is one the most important post-translational modifications because it controls intracellular protein trafficking typically resulting in protein degradation. Frequently ubiquitinated proteins are targeted to the proteasome for degradation in the cytosol. However, ubiquitinated membrane bound proteins can also be targeted for endocytosis and degradation in the lysosome. Ubiquitin-dependent degradation pathways have clear cancer relevance due to their integral involvement in protein quality control, regulation of immune responses, signal transduction, and cell cycle regulation. In spite of its fundamental importance, little is known regarding how proteins are specifically identified for ubiquitin-dependent degradation. In this article we review a newly discovered family of viral and cellular ubiquitin ligases called MARCH proteins. Recent studies of MARCH proteins define new paradigms showing how ubiquitin E3 ligases determine the intracellular location and fate of proteins.
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Affiliation(s)
- Xiaoli Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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10
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Loch S, Klauschies F, Schölz C, Verweij MC, Wiertz EJHJ, Koch J, Tampé R. Signaling of a varicelloviral factor across the endoplasmic reticulum membrane induces destruction of the peptide-loading complex and immune evasion. J Biol Chem 2008; 283:13428-36. [PMID: 18321854 DOI: 10.1074/jbc.m800226200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cytotoxic T lymphocytes eliminate infected cells upon surface display of antigenic peptides on major histocompatibility complex I molecules. To promote immune evasion, UL49.5 of several varicelloviruses interferes with the pathway of major histocompatibility complex I antigen processing. However, the inhibition mechanism has not been elucidated yet. Within the macromolecular peptide-loading complex we identified the transporter associated with antigen processing (TAP1 and TAP2) as the prime target of UL49.5. Moreover, we determined the active oligomeric state and crucial elements of the viral factor. Remarkably, the last two residues of the cytosolic tail of UL49.5 are essential for endoplasmic reticulum (ER)-associated proteasomal degradation of TAP. However, this process strictly requires additional signaling of an upstream regulatory element in the ER lumenal domain of UL49.5. Within this new immune evasion mechanism, we show for the first time that additive elements of a small viral factor and their signaling across the ER membrane are essential for targeted degradation of a multi-subunit membrane complex.
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Affiliation(s)
- Sandra Loch
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, D-60438, Frankfurt/Main, Germany
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11
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Abstract
To cope with the accumulation of unfolded or misfolded proteins the endoplasmic reticulum (ER) has evolved specific signalling pathways collectively called the unfolded protein response (UPR). Elucidation of the mechanisms governing ER stress signallinghas linked this response to the regulation of diverse physiologic processes as well as to the progression of a number of diseases. Interest in hereditary haemochromatosis (HH) has focused on the study of proteins implicated in iron homeostasis and on the identification of new alleles related with the disease. HFE has been amongst the preferred targets of interest, since the discovery that its C282Y mutation was associated with HH. However, the discrepancies between the disease penetrance and the frequency of this mutation have raised the possibility that its contribution to disease progression might go beyond the mere involvement in regulation of cellular iron uptake. Recent findings revealed that activation of the UPR is a feature of HH and that this stress response may be involved in the genesis of immunological anomalies associated with the disease. This review addresses the connection of the UPR with HH, including its role in MHC-I antigen presentation pathway and possible implications for new clinical approaches to HH.
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Affiliation(s)
- S F de Almeida
- Iron Genes and Immune System Laboratory, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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12
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Connolly N, Riddler S, Stanson J, Gooding W, Rinaldo CR, Ferrone S, Whiteside TL. Levels of antigen processing machinery components in dendritic cells generated for vaccination of HIV-1+ subjects. AIDS 2007; 21:1683-92. [PMID: 17690565 DOI: 10.1097/qad.0b013e32825eabbc] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate expression of the antigen processing machinery (APM) components and HLA molecules by monocyte-derived dendritic cells (DC) generated from chronically HIV-1 infected subjects on antiretroviral therapy (ART) and to assess their ability to ex vivo induce HIV-1 specific T cells. METHODS DC generated in 16 HLA-A2 positive patients were matured in cytokines, pulsed with HIV-1 or other viral peptides and tested in interferon (IFN)-gamma ELISPOT assays. Immature (i)DC, mature (m)DC and viral peptide-pulsed DC were studied by multiparameter quantitative flow cytometry for intracellular APM component expression and for HLA class I and II, beta-2 microglobulin and co-stimulatory molecule surface expression. DC from 13 normal donors served as controls. RESULTS Marked heterogeneity in APM component expression levels in iDC and mDC from HIV-1 positive subjects was observed. Nevertheless, the median levels were comparable to those in iDC and mDC, respectively, from normal donors. Patients' mDC pulsed with the HIV-1, influenza A, cytomegalovirus (CMV) or Epstein-Barr virus peptides induced IFN-gamma production by T cells specific for these peptides in ELISPOT assays. The frequency of T cells responsive to influenza A, cytomegalovirus or Epstein-Barr virus peptides was comparable in the patients and normal donors. CONCLUSIONS The APM component expression profiles of iDC and mDC were more heterogeneous in subjects with chronic HIV-1 infection on ART, than those in normal donors, although not statistically different. Ex vivo, patients' DC pulsed with HIV-1 peptides induced IFN-gamma production from autologous T cells. Thus, DC obtained from HIV-1 infected subjects on ART were phenotypically and functionally competent.
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Affiliation(s)
- Nancy Connolly
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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13
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Shin J, Park B, Lee S, Kim Y, Biegalke BJ, Kang S, Ahn K. A short isoform of human cytomegalovirus US3 functions as a dominant negative inhibitor of the full-length form. J Virol 2007; 80:5397-404. [PMID: 16699020 PMCID: PMC1472136 DOI: 10.1128/jvi.02397-05] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Human cytomegalovirus encodes four unique short (US) region proteins, each of which is independently sufficient for causing the down-regulation of major histocompatibility complex (MHC) class I molecules on the cell surface. This down-regulation enables infected cells to evade recognition by cytotoxic T lymphocytes (CTLs) but makes them vulnerable to lysis by natural killer (NK) cells, which lyse those cells that lack MHC class I molecules. The 22-kDa US3 glycoprotein is able to down-regulate the surface expression of MHC class I molecules by dual mechanisms: direct endoplasmic reticulum retention by physical association and/or tapasin inhibition. The alternative splicing of the US3 gene generates two additional products, including 17-kDa and 3.5-kDa truncated isoforms; however, the functional significance of these isoforms during viral infection is unknown. Here, we describe a novel mode of self-regulation of US3 function that uses the endogenously produced truncated isoform. The truncated isoform itself neither binds to MHC class I molecules nor prevents the full-length US3 from interacting with MHC class I molecules. Instead, the truncated isoform associates with tapasin and competes with full-length US3 for binding to tapasin; thus, it suppresses the action of US3 that causes the disruption of the function of tapasin. Our results indicate that the truncated isoform of the US3 locus acts as a dominant negative regulator of full-length US3 activity. These data reflect the manner in which the virus has developed temporal survival strategies during viral infection against immune surveillance involving both CTLs and NK cells.
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Affiliation(s)
- Jinwook Shin
- Department of Biological Sciences, Seoul National University, San 56-1, Sillim-dong, Gwanak-Gu, Seoul 151-747, Korea
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14
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Wang X, Herr RA, Chua WJ, Lybarger L, Wiertz EJHJ, Hansen TH. Ubiquitination of serine, threonine, or lysine residues on the cytoplasmic tail can induce ERAD of MHC-I by viral E3 ligase mK3. ACTA ACUST UNITED AC 2007; 177:613-24. [PMID: 17502423 PMCID: PMC2064207 DOI: 10.1083/jcb.200611063] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The mechanism by which substrates for endoplasmic reticulum–associated degradation are retrotranslocated to the cytosol remains largely unknown, although ubiquitination is known to play a key role. The mouse γ-herpesvirus protein mK3 is a viral RING-CH–type E3 ligase that specifically targets nascent major histocompatibility complex I heavy chain (HC) for degradation, thus blocking the immune detection of virus-infected cells. To address the question of how HC is retrotranslocated and what role mK3 ligase plays in this action, we investigated ubiquitin conjugation sites on HC using mutagenesis and biochemistry approaches. In total, our data demonstrate that mK3-mediated ubiquitination can occur via serine, threonine, or lysine residues on the HC tail, each of which is sufficient to induce the rapid degradation of HC. Given that mK3 has numerous cellular and viral homologues, it will be of considerable interest to determine the pervasiveness of this novel mechanism of ubiquitination.
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Affiliation(s)
- Xiaoli Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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15
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von Einem J, Smith PM, Van de Walle GR, O'Callaghan DJ, Osterrieder N. In vitro and in vivo characterization of equine herpesvirus type 1 (EHV-1) mutants devoid of the viral chemokine-binding glycoprotein G (gG). Virology 2007; 362:151-62. [PMID: 17250864 DOI: 10.1016/j.virol.2006.12.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 11/06/2006] [Accepted: 12/06/2006] [Indexed: 11/26/2022]
Abstract
Glycoprotein G (gG) of equine herpesvirus type 1 (EHV-1), a structural component of virions and secreted from virus-infected cells, was shown to bind to a variety of different chemokines and as such might be involved in immune modulation. Little is known, however, about its role in the replication cycle and infection of EHV-1 in vivo. Here we report on the function of gG in context of virus infection in vitro and in vivo. A gG deletion mutant of pathogenic EHV-1 strain RacL11 (vL11DeltagG) was constructed and analyzed. Deletion of gG had virtually no effect on the growth properties of vL11DeltagG in cell culture when compared to parental virus or a rescuant virus vL11DeltagGR, respectively, and virus titers and plaque formation were unaffected in the absence of the glycoprotein. Similarly, in the murine model of EHV-1 infection, no significant differences in virulence between the gG deletion mutant and RacL11 or vL11DeltagGR were found at high doses of infection. However, infection of mice at lower doses revealed that the gG deletion mutant was able to replicate to higher titers in lungs of infected mice. Additionally, these mice lost significantly more weight than those infected with RacL11 and a more pronounced inflammatory response in lungs was observed. Therefore we concluded that deletion of gG in EHV-1 seems to lead to an exacerbation of respiratory disease in the mouse.
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Affiliation(s)
- Jens von Einem
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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16
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Braun S, Zajakina A, Aleksejeva J, Sharipo A, Bruvere R, Ose V, Pumpens P, Garoff H, Meisel H, Kozlovska T. Proteasomal degradation of core protein variants from chronic hepatitis B patients. J Med Virol 2007; 79:1312-21. [PMID: 17607782 DOI: 10.1002/jmv.20939] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The accumulation of complex hepatitis B virus (HBV) variants with internal in-frame deletions in the C gene in immunosuppressed renal transplant recipients is associated with a severe course of the infection leading to end-stage liver disease (ESLD). A set of six HBV C genes with internal in-frame deletions corresponding to the pattern of HBV population in immunosuppressed patients has been expressed in two different eukaryotic cell lines. Synthesis and proteasomal degradation of HBV core (HBc) protein variants were compared with those of the wild-type HBc. In all cases, the steady-state level of internally deleted HBc proteins, predominantly with longer deletions, were considerably lower and turnover was significantly higher in comparison with those of the wild-type HBc, since all deletion variants were degraded rapidly via the proteasome pathway. Involvement and consequences of the proteasomal degradation machinery in the HBc protein turnover during HBV infection with complex HBV variants in the immunosuppressed patients are discussed.
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Affiliation(s)
- Sabine Braun
- Universitätsmedizin Berlin, Charité, Institut für Virologie, Campus Mitte, Charitéplatz 1, Berlin, Germany
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17
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Ohmura-Hoshino M, Goto E, Matsuki Y, Aoki M, Mito M, Uematsu M, Hotta H, Ishido S. A novel family of membrane-bound E3 ubiquitin ligases. J Biochem 2006; 140:147-54. [PMID: 16954532 DOI: 10.1093/jb/mvj160] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A novel E3 ubiquitin ligase family that consists of viral E3 ubiquitin ligases (E3s) and their mammalian homologues was recently discovered. These novel E3s are membrane-bound molecules that share the secondary structure and catalytic domain for E3 activity. All family members have two transmembrane regions at the center and a RING-CH domain at the amino terminus. Forced expression of these novel E3s has been shown to reduce the surface expression of various membrane proteins through ubiquitination of target molecules. Initial examples of viral E3s were identified in Kaposi's sarcoma associated herpesvirus (KSHV) and murine gamma-herpesvirus 68 (MHV-68) and have been designated as modulator of immune recognition (MIR) 1, 2 and mK3, respectively. MIR 1, 2 and mK3 are able to down-regulate MHC class I molecule expression, and mK3 is required to establish an effective latent viral infection in vivo. The first characterized mammalian homologue to MIR 1, 2 and mK3 is c-MIR/MARCH VIII. Forced expression of c-MIR/MARCH VIII down-regulates B7-2, a co-stimulatory molecule important for antigen presentation. Subsequently, several mammalian molecules related to c-MIR/MARCH VIII have been characterized and named as membrane associated RING-CH (MARCH) family. However, the precise physiological function of MARCH family members remains as yet unknown.
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Affiliation(s)
- Mari Ohmura-Hoshino
- Laboratory for Infectious Immunity, RIKEN Research Center for Allergy and Immunology 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045
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18
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Wiertz EJ, Devlin R, Collins HL, Ressing ME. Herpesvirus interference with major histocompatibility complex class II-restricted T-cell activation. J Virol 2006; 81:4389-96. [PMID: 17079308 PMCID: PMC1900142 DOI: 10.1128/jvi.01525-06] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Emmanuel J Wiertz
- Department of Medical Microbiology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
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Delgado-Lopez F, Horwitz MS. Adenovirus RIDalphabeta complex inhibits lipopolysaccharide signaling without altering TLR4 cell surface expression. J Virol 2006; 80:6378-86. [PMID: 16775326 PMCID: PMC1488987 DOI: 10.1128/jvi.02350-05] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The transmembrane heterotrimer complex 10.4K/14.5K, also known as RID (for "receptor internalization and degradation"), is encoded by the adenovirus E3 region, and it down-regulates the cell surface expression of several unrelated receptors. We recently showed that RID expression correlates with down-regulation of the cell surface expression of the tumor necrosis factor (TNF) receptor 1 in several human cells. This observation provided the first mechanistic explanation for the inhibition of TNF alpha-induced chemokines by RID. Here we analyze the immunoregulatory activities of RID on lipopolysaccharide (LPS) and interleukin-1 beta (IL-1beta)-mediated responses. Although both signaling pathways are strongly inhibited by RID, the chemokines up-regulated by IL-1beta stimulation are only marginally inhibited. In addition, RID inhibits signaling induced by LPS without affecting the expression of the LPS receptor Toll-like receptor 4, demonstrating that RID need not target degradation of the receptor to alter signal transduction. Taken together, our data demonstrate the inhibitory effect of RID on two additional cell surface receptor-mediated signaling pathways involved in inflammatory processes. The data suggest that RID has intracellular targets that impair signal transduction and chemokine expression without evidence of receptor down-regulation.
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Affiliation(s)
- Fernando Delgado-Lopez
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Forchheimer Building, Room 411, Bronx, NY 10461, USA.
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20
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Ohmura-Hoshino M, Matsuki Y, Aoki M, Goto E, Mito M, Uematsu M, Kakiuchi T, Hotta H, Ishido S. Inhibition of MHC Class II Expression and Immune Responses by c-MIR. THE JOURNAL OF IMMUNOLOGY 2006; 177:341-54. [PMID: 16785530 DOI: 10.4049/jimmunol.177.1.341] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We previously reported a novel E3 ubiquitin ligase (E3), designated as c-MIR, which targets B7-2 to lysosomal degradation and down-regulates the B7-2 surface expression through ubiquitination of its cytoplasmic tail. B7-2 is well known as a costimulatory molecule for Ag presentation, suggesting that the manipulation of c-MIR expression modulates immune responses in vivo. To examine this hypothesis, we generated genetically modified mice in which c-MIR was expressed under an invariant chain (Ii) promoter. Dendritic cells derived from genetically engineered mice showed low ability to present Ags. In addition, these mice showed resistance to the onset of experimental autoimmune encephalomyelitis and an impaired development of CD4 T cells in the thymus and the periphery. These findings led us to conclude that MHC class II (MHC II) is an additional target for c-MIR. Indeed, forced expression of c-MIR in several B cell lines down-regulated the surface expression of MHC II, and down-regulation was found to depend on the presence of a single lysine residue in the cytoplasmic tail of the I-A beta-chain. In a reconstitution system using 293T cells, we found that the lysine residue at position 225 in the I-A beta-chain was ubiquitinated by c-MIR. To our knowledge, c-MIR is the first example of an E3 that is capable of inhibiting MHC II expression. Our findings suggest that c-MIR might potently regulate immune responses in vivo.
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Affiliation(s)
- Mari Ohmura-Hoshino
- Laboratory for Infectious Immunity, The Institute of Physical and Chemical Research (RIKEN), Research Center for Allergy and Immunology, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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21
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Block TM, Mehta AS, Blumberg BS, Dwek RA. Does rapid oligomerization of hepatitis B envelope proteins play a role in resistance to proteasome degradation and enhance chronicity? DNA Cell Biol 2006; 25:165-70. [PMID: 16569195 DOI: 10.1089/dna.2006.25.165] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
This review discusses the nature of hepatitis B and C chronicity from a virological perspective. Work described in the literature and our in vitro studies of HBV polypeptide morphogenesis lead us to speculate about a role for HBsAg complex formation in immune evasion that may be especially important during the initial period of infection. Briefly, although viral structural proteins do eventually provide epitopes recognized by the host, we suggest that these HBs Ag complexes, which may themselves be refractory to proteasomal degradation, are an important way by which the virus shields its epitopes and evades early recognition by the cellular immune system. This suggests a central strategy by which the virus has evolved, structurally, to enable the establishment of persistent infection of its host. The concept offers an explanation for the nearly unidirectional and rapid kinetics whereby HBV proteins form multimers and generate a surplus of viral structures that have not been thought to serve any useful structural purpose.
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Affiliation(s)
- Timothy M Block
- Department of Microbiology and Immunology, Drexel Institute for Biotechnology and Virology Research, Drexel University College of Medicine, Doylestown, Pennsylvania 18901, USA.
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Mansouri M, Douglas J, Rose PP, Gouveia K, Thomas G, Means RE, Moses AV, Früh K. Kaposi sarcoma herpesvirus K5 removes CD31/PECAM from endothelial cells. Blood 2006; 108:1932-40. [PMID: 16601245 PMCID: PMC1635550 DOI: 10.1182/blood-2005-11-4404] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The transmembrane ubiquitin ligase K5/MIR2 of Kaposi sarcoma herpesvirus (KSHV) mediates internalization and lysosomal degradation of glycoproteins involved in antigen presentation and co-stimulation. In endothelial cells (ECs), K5 additionally reduced expression of CD31/platelet-endothelial cell adhesion molecule (PECAM), an adhesion molecule regulating cell-cell interactions of ECs, platelets, monocytes, and T cells. K5 also reduced EC migration, a CD31-dependent process. Unlike other K5 substrates, both newly synthesized and pre-existing CD31 molecules were targeted by K5. K5 was transported to the cell surface and ubiquitinated pre-existing CD31, resulting in endocytosis and lysosomal degradation. In the endoplasmic reticulum, newly synthesized CD31 was degraded by proteasomes, which required binding of phosphofurin acidic cluster sorting protein-2 (PACS-2) to acidic residues in the carboxyterminal tail of K5. Thus, CD31, a novel target of K5, is efficiently removed from ECs by a dual degradation mechanism that is regulated by the subcellular sorting of the ubiquitin ligase. K5-mediated degradation of CD31 is likely to affect EC function in KS tumors.
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Affiliation(s)
- Mandana Mansouri
- Vaccine and Gene Therapy Institute and Vollum Institute, Oregon Health and Science University, Portland, OR, USA
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Roy CR, Salcedo SP, Gorvel JPE. Pathogen-endoplasmic-reticulum interactions: in through the out door. Nat Rev Immunol 2006; 6:136-47. [PMID: 16491138 PMCID: PMC7097709 DOI: 10.1038/nri1775] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The endoplasmic reticulum (ER) is a crucial intracellular organelle that is involved in the biosynthesis of cellular molecules, including proteins, carbohydrates and lipids. These become constituents of the ER or are transported to the Golgi, plasma membrane, endosomes and lysosomes. The ER is involved in the transport of both MHC class I and class II complexes to the cell surface. It is the site of peptide loading onto MHC class I molecules, and it is important for regulation of the secretion of soluble immune mediators. Perturbation in ER–Golgi biogenesis affects antigen presentation and immune effector functions, so it is not surprising that the ER is a target for some pathogens. Several pathogens have developed strategies to modulate phagosome maturation and therefore avoid phagosome–lysosome fusion and the subsequent degradation of the pathogen: for example, by generating an ER-derived vacuole. In some cases, this has the added benefit of disrupting ER function. Toxoplasma gondii, Brucella spp. and Legionella pneumophila depend on ER-derived niches for growth, but the precise effects of these pathogen–ER interactions on the immune response are still unclear. Several viruses target the ER and interfere with antigen presentation by MHC class I molecules: for example, hepatitis C virus and human cytomegalovirus. Despite this, the ER contributes to host defence against microorganisms, through its role in autophagy, as well as through the ER stress response and the interferon-induced ER-resident proteins (such as viperin and the p47 GTPases).
Different pathogens have evolved distinct strategies to promote their survival in host cells. This Review describes the contribution of the endoplasmic reticulum to host defence and the mechanisms by which pathogens interacting with the endoplasmic reticulum subvert the host immune response. A key determinant for the survival of intracellular pathogens is their ability to subvert the cellular processes of the host to establish a compartment that allows replication. Although most microorganisms internalized by host cells are efficiently cleared following fusion with lysosomes, many pathogens have evolved mechanisms to escape this degradation. In this Review, we provide insight into the molecular processes that are targeted by pathogens that interact with the endoplasmic reticulum and thereby subvert the immune response, ensure their survival intracellularly and cause disease. We also discuss how the endoplasmic reticulum 'strikes back' and controls microbial growth.
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Affiliation(s)
- Craig R. Roy
- Section of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, 295 Congress Avenue, New Haven, 065362 Connecticut USA
| | - Suzana P. Salcedo
- Centre dImmunologie INSERM-CNRS de Marseille-Luminy, Case 906, Marseille, 13288 Cedex 9 France
| | - Jean-Pierre E. Gorvel
- Centre dImmunologie INSERM-CNRS de Marseille-Luminy, Case 906, Marseille, 13288 Cedex 9 France
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Abstract
Multicellular organisms possess very sophisticated defense mechanisms that are designed to effectively counter the continual microbial insult of the environment within the vertebrate host. However, successful microbial pathogens have in turn evolved complex and efficient methods to overcome innate and adaptive immune mechanisms, which can result in disease or chronic infections. Although the various virulence strategies used by viral and bacterial pathogens are numerous, there are several general mechanisms that are used to subvert and exploit immune systems that are shared between these diverse microbial pathogens. The success of each pathogen is directly dependant on its ability to mount an effective anti-immune response within the infected host, which can ultimately result in acute disease, chronic infection, or pathogen clearance. In this review, we highlight and compare some of the many molecular mechanisms that bacterial and viral pathogens use to evade host immune defenses.
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Affiliation(s)
- B Brett Finlay
- Michael Smith Laboratories, University of British Columbia, Vancouver, B.C. V6T 1Z4 Canada.
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Wang X, Ye Y, Lencer W, Hansen TH. The viral E3 ubiquitin ligase mK3 uses the Derlin/p97 endoplasmic reticulum-associated degradation pathway to mediate down-regulation of major histocompatibility complex class I proteins. J Biol Chem 2006; 281:8636-44. [PMID: 16446359 DOI: 10.1074/jbc.m513920200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ubiquitin E3 ligases are important cellular components for endoplasmic reticulum (ER)-associated degradation due to their role in substrate-specific ubiquitination, which is required for retrotranslocation (dislocation) of most unwanted proteins from the ER to the cytosol for proteasome degradation. However, our understanding of the molecular mechanisms of how E3 ligases confer substrate-specific recognition, and their role in substrate retrotranslocation is limited especially in mammalian cells. mK3 is a type III ER membrane protein encoded by murine gamma herpesvirus 68. As conferred by its N-terminal RING-CH domain, mK3 has E3 ubiquitin ligase activity. In its role as an immune evasion protein, mK3 specifically targets nascent major histocompatibility complex class I heavy chains (HC) for rapid degradation. The mechanism by which mK3 extracts HC from the ER membrane into the cytosol for proteasome-mediated degradation is unknown. Evidence is presented here that HC down-regulation by mK3 is dependent on the p97 AAA-ATPase. By contrast, the kK5 protein of Kaposi's sarcoma-associated herpesvirus is p97-independent despite the fact that it is highly homologous to mK3. mK3 protein was also found in physical association with Derlin1, an ER protein recently implicated in the retrotranslocation of HC by immune evasion protein US11, but not US2, of human cytomegalovirus. The mechanistic implications of these findings are discussed.
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Affiliation(s)
- Xiaoli Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Abstract
Relatively small genomes and high replication rates allow viruses and bacteria to accumulate mutations. This continuously presents the host immune system with new challenges. On the other side of the trenches, an increasingly well-adjusted host immune response, shaped by coevolutionary history, makes a pathogen's life a rather complicated endeavor. It is, therefore, no surprise that pathogens either escape detection or modulate the host immune response, often by redirecting normal cellular pathways to their advantage. For the purpose of this chapter, we focus mainly on the manipulation of the class I and class II major histocompatibility complex (MHC) antigen presentation pathways and the ubiquitin (Ub)-proteasome system by both viral and bacterial pathogens. First, we describe the general features of antigen presentation pathways and the Ub-proteasome system and then address how they are manipulated by pathogens. We discuss the many human cytomegalovirus (HCMV)-encoded immunomodulatory genes that interfere with antigen presentation (immunoevasins) and focus on the HCMV immunoevasins US2 and US11, which induce the degradation of class I MHC heavy chains by the proteasome by catalyzing their export from the endoplasmic reticulum (ER)-membrane into the cytosol, a process termed ER dislocation. US2- and US11-mediated subversion of ER dislocation ensures proteasomal degradation of class I MHC molecules and presumably allows HCMV to avoid recognition by cytotoxic T cells, whilst providing insight into general aspects of ER-associated degradation (ERAD) which is used by eukaryotic cells to purge their ER of defective proteins. We discuss the similarities and differences between the distinct pathways co-opted by US2 and US11 for dislocation and degradation of human class I MHC molecules and also a putatively distinct pathway utilized by the murine herpes virus (MHV)-68 mK3 immunoevasin for ER dislocation of murine class I MHC. We speculate on the implications of the three pathogen-exploited dislocation pathways to cellular ER quality control. Moreover, we discuss the ubiquitin (Ub)-proteasome system and its position at the core of antigen presentation as proteolysis and intracellular trafficking rely heavily on Ub-dependent processes. We add a few examples of manipulation of the Ub-proteasome system by pathogens in the context of the immune system and such diverse aspects of the host-pathogen relationship as virus budding, bacterial chromosome integration, and programmed cell death, to name a few. Finally, we speculate on newly found pathogen-encoded deubiquitinating enzymes (DUBs) and their putative roles in modulation of host-pathogen interactions.
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Affiliation(s)
- Joana Loureiro
- Whitehead Institute, 9 Cambridge Center, Cambridge, Massachusetts, USA
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Abstract
BACKGROUND Viral respiratory tract infections cause significant morbidity and mortality. Respiratory viruses are suspected to play a role in the inception of asthma early in life. Respiratory syncytial virus (RSV) is the most common cause of infant bronchiolitis, which is associated with the development of childhood wheezing and asthma. However, it is not clear whether this association is "causal" or "circumstantial." METHODS Animal models have been pivotal in studying the pathophysiology of viral respiratory infections. Various approaches to assessing airway inflammation and function have been used to define the mechanisms of virus-induced airway dysfunction and to address clinically relevant questions regarding the role of RSV in wheezing and asthma after bronchiolitis. RESULTS Viral lower respiratory tract infections alter airway function in humans and animals. The extent and duration of the alterations may depend on the virus itself, host factors and environmental factors. Animal studies demonstrated that viral infection induces airway hyperresponsiveness and enhances this alteration in the allergen-sensitized and exposed host. This altered airway function is mediated by immune and neurogenic inflammatory mechanisms. Recent studies in mice show that neonatal RSV infection sensitizes the newborn to develop an asthma-like phenotype on reinfection, providing further opportunities to investigate the role of RSV in postbronchiolitis wheezing and asthma in this animal model. CONCLUSIONS Further studies are needed to fully establish the mechanisms underlying the pathophysiology of viral respiratory tract infections and to clarify their role in the inception and/or progression of chronic airway diseases such as asthma. The results of ongoing therapeutic studies promise to minimize the impact of such viral infections.
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Affiliation(s)
- Azzeddine Dakhama
- Division of Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO, USA.
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Iannello A, Debbeche O, Martin E, Attalah LH, Samarani S, Ahmad A. Viral strategies for evading antiviral cellular immune responses of the host. J Leukoc Biol 2005; 79:16-35. [PMID: 16204622 DOI: 10.1189/jlb.0705397] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The host invariably responds to infecting viruses by activating its innate immune system and mounting virus-specific humoral and cellular immune responses. These responses are aimed at controlling viral replication and eliminating the infecting virus from the host. However, viruses have evolved numerous strategies to counter and evade host's antiviral responses. Providing specific examples from the published literature, we discuss in this review article various strategies that viruses have developed to evade antiviral cellular responses of the host. Unraveling these viral strategies allows a better understanding of the host-pathogen interactions and their coevolution. This knowledge is important for identifying novel molecular targets for developing antiviral reagents. Finally, it may also help devise new knowledge-based strategies for developing antiviral vaccines.
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Affiliation(s)
- Alexandre Iannello
- Ste-Justine Hospital Research Center, Department of Microbiology and Immunology, University of Montreal, Quebec, Canada
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