1
|
Byun H, Gou Y, Zook A, Lozano MM, Dudley JP. ERAD and how viruses exploit it. Front Microbiol 2014; 5:330. [PMID: 25071743 PMCID: PMC4080680 DOI: 10.3389/fmicb.2014.00330] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/16/2014] [Indexed: 01/09/2023] Open
Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) is a universally important process among eukaryotic cells. ERAD is necessary to preserve cell integrity since the accumulation of defective proteins results in diseases associated with neurological dysfunction, cancer, and infections. This process involves recognition of misfolded or misassembled proteins that have been translated in association with ER membranes. Recognition of ERAD substrates leads to their extraction through the ER membrane (retrotranslocation or dislocation), ubiquitination, and destruction by cytosolic proteasomes. This review focuses on ERAD and its components as well as how viruses use this process to promote their replication and to avoid the immune response.
Collapse
Affiliation(s)
- Hyewon Byun
- Department of Molecular Biosciences, Center for Infectious Diseases and Institute for Cellular and Molecular Biology, The University of Texas at Austin Austin, TX, USA
| | - Yongqiang Gou
- Department of Molecular Biosciences, Center for Infectious Diseases and Institute for Cellular and Molecular Biology, The University of Texas at Austin Austin, TX, USA
| | - Adam Zook
- Department of Molecular Biosciences, Center for Infectious Diseases and Institute for Cellular and Molecular Biology, The University of Texas at Austin Austin, TX, USA
| | - Mary M Lozano
- Department of Molecular Biosciences, Center for Infectious Diseases and Institute for Cellular and Molecular Biology, The University of Texas at Austin Austin, TX, USA
| | - Jaquelin P Dudley
- Department of Molecular Biosciences, Center for Infectious Diseases and Institute for Cellular and Molecular Biology, The University of Texas at Austin Austin, TX, USA
| |
Collapse
|
2
|
Zuo J, Rowe M. Herpesviruses placating the unwilling host: manipulation of the MHC class II antigen presentation pathway. Viruses 2012; 4:1335-53. [PMID: 23012630 PMCID: PMC3446767 DOI: 10.3390/v4081335] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 08/14/2012] [Accepted: 08/15/2012] [Indexed: 12/18/2022] Open
Abstract
Lifelong persistent infection by herpesviruses depends on the balance between host immune responses and viral immune evasion. CD4 T cells responding to antigens presented on major histocompatibility complex class II (MHC-II) molecules are known to play an important role in controlling herpesvirus infections. Here we review, with emphasis on human herpesvirus infections, the strategies evolved to evade CD4 T cell immunity. These viruses target multiple points on the MHC class II antigen presentation pathway. The mechanisms include: suppression of CIITA to inhibit the synthesis of MHC class II molecules, diversion or degradation of HLA-DR molecules during membrane transport, and direct targeting of the invariant chain chaperone of HLA-DR.
Collapse
Affiliation(s)
- Jianmin Zuo
- Cancer Research UK Birmingham Cancer Centre, University of Birmingham, Birmingham B15 2TT, UK.
| | | |
Collapse
|
3
|
Gnana-Prakasam JP, Ananth S, Prasad PD, Zhang M, Atherton SS, Martin PM, Smith SB, Ganapathy V. Expression and iron-dependent regulation of succinate receptor GPR91 in retinal pigment epithelium. Invest Ophthalmol Vis Sci 2011; 52:3751-8. [PMID: 21357408 DOI: 10.1167/iovs.10-6722] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE GPR91, a succinate receptor, is expressed in retinal ganglion cells and induces vascular endothelial growth factor (VEGF) expression. RPE also expresses VEGF, but whether this cell expresses GPR91 is not known. Excessive iron is also proangiogenic, and hemochromatosis is associated with iron overload. Therefore, we examined the expression and iron-dependent regulation of GPR91 in the RPE. METHODS GPR91 expression was examined by RT-PCR and immunohistochemistry. Hemochromatosis mice, cytomegalovirus (CMV) infection of retina, expression of CMV-US2 in RPE, and exposure of RPE to ferric ammonium citrate (FAC) were used to examine the iron-dependent regulation of GPR91 expression. VEGF expression was quantified by qPCR. Knockdown of GPR91 in ARPE-19 cells was achieved with shRNA. RESULTS GPR91 was expressed in RPE but only in the apical membrane. Retinal expression of GPR91 was higher in hemochromatosis (Hfe(-/-)) mice than in wild-type (WT) mice. Primary RPE cells from Hfe(-/-) mice had increased GPR91 expression compared with WT RPE cells. Iron accumulation in cells induced by CMV infection, expression of CMV-US2, or treatment with FAC increased GPR91 expression. VEGF expression in the Hfe(-/-) mouse retina was increased at ages younger than 18 months, but the expression was downregulated at older ages. The involvement of GPR91 in succinate-induced expression of VEGF in RPE cells was confirmed with GPR91-specific shRNA. CONCLUSIONS GPR91 is expressed in the RPE with specific localization to the apical membrane, indicating that succinate in the subretinal space serves as the GPR91 agonist. Excessive iron in the retina and RPE enhances GPR91 expression; however, VEGF expression does not always parallel GPR91 expression.
Collapse
Affiliation(s)
- Jaya P Gnana-Prakasam
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia 30912, USA
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Gnana-Prakasam JP, Martin PM, Smith SB, Ganapathy V. Expression and function of iron-regulatory proteins in retina. IUBMB Life 2010; 62:363-70. [PMID: 20408179 DOI: 10.1002/iub.326] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Iron is essential for cell survival and function; yet excess iron is toxic to cells. Therefore, the cellular and whole-body levels of iron are regulated exquisitely. At least a dozen proteins participate in the regulation of iron homeostasis. Hemochromatosis, a genetic disorder of iron overload, is caused by mutations in at least five genes, namely HFE, hemojuvelin, Transferrin receptor 2, ferroportin, and hepcidin. Retina is separated from systemic circulation by inner and outer blood-retinal barriers; therefore it is widely believed that this tissue is immune to changes in systemic circulation. Even though hemochromatosis is associated with iron overload and dysfunction of a variety of systemic organs, little is known on the effects of this disease on the retina. Recent studies have shown that all five genes that are associated with hemochromatosis are expressed in the retina in a cell type-specific manner. The retinal pigment epithelium, which forms the outer blood-retinal barrier, expresses all of these five genes. It is therefore clearly evident that iron homeostasis in the retina is maintained locally by active participation of various iron-regulatory proteins. Excess iron is detrimental to the retina as evidenced from human studies and from mouse models of iron overload. Retinal iron homeostasis is disrupted in various clinical conditions such as hemochromatosis, aceruloplasminemia, age-related macular degeneration, and bacterial and viral infections.
Collapse
Affiliation(s)
- Jaya P Gnana-Prakasam
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA, USA
| | | | | | | |
Collapse
|
5
|
Protein disulphide isomerase is required for signal peptide peptidase-mediated protein degradation. EMBO J 2009; 29:363-75. [PMID: 19942855 DOI: 10.1038/emboj.2009.359] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 11/04/2009] [Indexed: 11/08/2022] Open
Abstract
The human cytomegalovirus glycoprotein US2 induces dislocation of MHC class I heavy chains from the endoplasmic reticulum (ER) into the cytosol and targets them for proteasomal degradation. Signal peptide peptidase (SPP) has been shown to be integral for US2-induced dislocation of MHC class I heavy chains although its mechanism of action remains poorly understood. Here, we show that knockdown of protein disulphide isomerase (PDI) by RNA-mediated interference inhibited the degradation of MHC class I molecules catalysed by US2 but not by its functional homolog US11. Overexpression of the substrate-binding mutant of PDI, but not the catalytically inactive mutant, dominant-negatively inhibited US2-mediated dislocation of MHC class I molecules by preventing their release from US2. Furthermore, PDI associated with SPP independently of US2 and knockdown of PDI inhibited SPP-mediated degradation of CD3delta but not Derlin-1-dependent degradation of CFTR DeltaF508. Together, our data suggest that PDI is a component of the SPP-mediated ER-associated degradation machinery.
Collapse
|
6
|
Stagg HR, Thomas M, van den Boomen D, Wiertz EJHJ, Drabkin HA, Gemmill RM, Lehner PJ. The TRC8 E3 ligase ubiquitinates MHC class I molecules before dislocation from the ER. ACTA ACUST UNITED AC 2009; 186:685-92. [PMID: 19720873 PMCID: PMC2742190 DOI: 10.1083/jcb.200906110] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human cytomegalovirus uses an E3 ubiquitin ligase to divert MHC I molecules into the ER-associated degradation pathway for destruction. The US2 and US11 gene products of human cytomegalovirus promote viral evasion by hijacking the endoplasmic reticulum (ER)–associated degradation (ERAD) pathway. US2 and US11 initiate dislocation of newly translocated major histocompatibility complex class I (MHC I) from the ER to the cytosol for proteasome-mediated degradation, thereby decreasing cell surface MHC I. Despite being instrumental in elucidating the mammalian ERAD pathway, the responsible E3 ligase or ligases remain unknown. Using a functional small interfering RNA library screen, we now identify TRC8 (translocation in renal carcinoma, chromosome 8 gene), an ER-resident E3 ligase previously implicated as a hereditary kidney cancer gene, as required for US2-mediated MHC I ubiquitination. Depletion of TRC8 prevents MHC I ubiquitination and dislocation by US2 and restores cell surface MHC I. TRC8 forms an integral part of a novel multiprotein ER complex that contains MHC I, US2, and signal peptide peptidase. Our data show that the TRC8 E3 ligase is required for MHC I dislocation from the ER and identify a new complex associated with mammalian ERAD.
Collapse
Affiliation(s)
- Helen R Stagg
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB20XY, England, UK
| | | | | | | | | | | | | |
Collapse
|
7
|
Expression of the iron-regulatory protein haemojuvelin in retina and its regulation during cytomegalovirus infection. Biochem J 2009; 419:533-43. [PMID: 19191760 DOI: 10.1042/bj20082240] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Haemochromatosis is a genetic disorder of iron overload resulting from loss-of-function mutations in genes coding for the iron-regulatory proteins HFE [HLA-like protein involved in iron (Fe) homoeostasis], transferrin receptor 2, ferroportin, hepcidin and HJV (haemojuvelin). Expression of the first four genes coding for these proteins in retina has been established. Here we report on the expression of HJV. Since infection of retina with CMV (cytomegalovirus) causes blindness, we also investigated the expression of HJV and other iron-regulatory proteins in retina during CMV infection. HJV (HJV gene) mRNA was expressed in RPE (retinal pigment epithelium)/eyecup and neural retina in mouse. In situ hybridization and immunohistochemistry confirmed the presence of HJV mRNA and protein in RPE, outer and inner nuclear layers, and ganglion cell layer. Immunocytochemistry with cell lines and primary cell cultures showed HJV expression in RPE and Müller cells. In RPE, the expression was restricted to apical membrane. Infection of primary cultures of mouse RPE with CMV increased HJV mRNA and protein levels. Under similar conditions, HFE (HFE gene) mRNA levels were not altered, but HFE protein was decreased. Hepcidin expression was, however, not altered. These findings were demonstrable in vivo with CMV-infected mouse retina. The CMV-induced up-regulation of HJV in RPE was independent of changes in HFE because the phenomenon was also seen in HFE-null RPE cells. CMV-infected primary RPE cells showed evidence of iron accumulation and oxidative stress, as indicated by increased levels of ferritin and hydroxynonenal. The observed changes in HJV expression and iron status during CMV infection in retina may have significance in the pathophysiology of CMV retinitis.
Collapse
|
8
|
Li D, Qian L, Chen C, Shi M, Yu M, Hu M, Song L, Shen B, Guo N. Down-regulation of MHC class II expression through inhibition of CIITA transcription by lytic transactivator Zta during Epstein-Barr virus reactivation. THE JOURNAL OF IMMUNOLOGY 2009; 182:1799-809. [PMID: 19201831 DOI: 10.4049/jimmunol.0802686] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The presentation of peptides to T cells by MHC class II molecules is of critical importance in specific recognition to a pathogen by the immune system. The level of MHC class II directly influences T lymphocyte activation. The aim of this study was to identify the possible mechanisms of the down-regulation of MHC class II expression by Zta during EBV lytic cycle. The data in the present study demonstrated that ectopic expression of Zta can strongly inhibit the constitutive expression of MHC class II and CIITA in Raji cells. The negative effect of Zta on the CIITA promoter activity was also observed. Scrutiny of the DNA sequence of CIITA promoter III revealed the presence of two Zta-response element (ZRE) motifs that have complete homology to ZREs in the DR and left-hand side duplicated sequence promoters of EBV. By chromatin immunoprecipitation assays, the binding of Zta to the ZRE(221) in the CIITA promoter was verified. Site-directed mutagenesis of three conserved nucleotides of the ZRE(221) substantially disrupted Zta-mediated inhibition of the CIITA promoter activity. Oligonucleotide pull-down assay showed that mutation of the ZRE(221) dramatically abolished Zta binding. Analysis of the Zta mutant lacking DNA binding domain revealed that the DNA-binding activity of Zta is required for the trans repression of CIITA. The expression of HLA-DRalpha and CIITA was restored by Zta gene silencing. The data indicate that Zta may act as an inhibitor of the MHC class II pathway, suppressing CIITA transcription and thus interfering with the expression of MHC class II molecules.
Collapse
Affiliation(s)
- Dan Li
- Department of Molecular Immunology, Institute of Basic Medical Sciences, Beijing, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Miller-Kittrell M, Sparer TE. Feeling manipulated: cytomegalovirus immune manipulation. Virol J 2009; 6:4. [PMID: 19134204 PMCID: PMC2636769 DOI: 10.1186/1743-422x-6-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 01/09/2009] [Indexed: 02/03/2023] Open
Abstract
No one likes to feel like they have been manipulated, but in the case of cytomegalovirus (CMV) immune manipulation, we do not really have much choice. Whether you call it CMV immune modulation, manipulation, or evasion, the bottom line is that CMV alters the immune response in such a way to allow the establishment of latency with lifelong shedding. With millions of years of coevolution within their hosts, CMVs, like other herpesviruses, encode numerous proteins that can broadly influence the magnitude and quality of both innate and adaptive immune responses. These viral proteins include both homologues of host proteins, such as MHC class I or chemokine homologues, and proteins with little similarity to any other known proteins, such as the chemokine binding protein. Although a strong immune response is launched against CMV, these virally encoded proteins can interfere with the host's ability to efficiently recognize and clear virus, while others induce or alter specific immune responses to benefit viral replication or spread within the host. Modulation of host immunity allows survival of both the virus and the host. One way of describing it would be a kind of "mutually assured survival" (as opposed to MAD, Mutually Assured Destruction). Evaluation of this relationship provides important insights into the life cycle of CMV as well as a greater understanding of the complexity of the immune response to pathogens in general.
Collapse
Affiliation(s)
- Mindy Miller-Kittrell
- Department of Microbiology, University of Tennessee, 1414 Cumberland Ave, Knoxville, TN, USA.
| | | |
Collapse
|
10
|
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: 1.6] [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.
| | | | | | | |
Collapse
|
11
|
de la Fuente C, Gupta MV, Klase Z, Strouss K, Cahan P, McCaffery T, Galante A, Soteropoulos P, Pumfery A, Fujii M, Kashanchi F. Involvement of HTLV-I Tax and CREB in aneuploidy: a bioinformatics approach. Retrovirology 2006; 3:43. [PMID: 16822311 PMCID: PMC1553470 DOI: 10.1186/1742-4690-3-43] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 07/05/2006] [Indexed: 11/23/2022] Open
Abstract
Background Adult T-cell leukemia (ATL) is a complex and multifaceted disease associated with human T-cell leukemia virus type 1 (HTLV-I) infection. Tax, the viral oncoprotein, is considered a major contributor to cell cycle deregulation in HTLV-I transformed cells by either directly disrupting cellular factors (protein-protein interactions) or altering their transcription profile. Tax transactivates these cellular promoters by interacting with transcription factors such as CREB/ATF, NF-κB, and SRF. Therefore by examining which factors upregulate a particular set of promoters we may begin to understand how Tax orchestrates leukemia development. Results We observed that CTLL cells stably expressing wild-type Tax (CTLL/WT) exhibited aneuploidy as compared to a Tax clone deficient for CREB transactivation (CTLL/703). To better understand the contribution of Tax transactivation through the CREB/ATF pathway to the aneuploid phenotype, we performed microarray analysis comparing CTLL/WT to CTLL/703 cells. Promoter analysis of altered genes revealed that a subset of these genes contain CREB/ATF consensus sequences. While these genes had diverse functions, smaller subsets of genes were found to be involved in G2/M phase regulation, in particular kinetochore assembly. Furthermore, we confirmed the presence of CREB, Tax and RNA Polymerase II at the p97Vcp and Sgt1 promoters in vivo through chromatin immunoprecipitation in CTLL/WT cells. Conclusion These results indicate that the development of aneuploidy in Tax-expressing cells may occur in response to an alteration in the transcription profile, in addition to direct protein interactions.
Collapse
MESH Headings
- Aneuploidy
- Binding Sites
- Chromatin Immunoprecipitation
- Computational Biology/methods
- Cyclic AMP Response Element-Binding Protein/genetics
- Cyclic AMP Response Element-Binding Protein/metabolism
- DNA Polymerase II/genetics
- DNA Polymerase II/metabolism
- Gene Expression Profiling/methods
- Gene Expression Regulation
- Gene Products, tax/biosynthesis
- Gene Products, tax/genetics
- Gene Products, tax/metabolism
- Genes, pX
- Human T-lymphotropic virus 1/genetics
- Humans
- Kinetochores/physiology
- Leukemia, Prolymphocytic, T-Cell/genetics
- Leukemia, Prolymphocytic, T-Cell/virology
- Oligonucleotide Array Sequence Analysis
- Promoter Regions, Genetic
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/physiology
- Transfection
Collapse
Affiliation(s)
- Cynthia de la Fuente
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Madhur V Gupta
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Zachary Klase
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Katharine Strouss
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Patrick Cahan
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Timothy McCaffery
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Anthony Galante
- Center for Applied Genomics, Public Health Research Institute, Newark, NJ 07103, USA
| | - Patricia Soteropoulos
- Center for Applied Genomics, Public Health Research Institute, Newark, NJ 07103, USA
| | - Anne Pumfery
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Masahiro Fujii
- Department of Immunotherapeutics, Niigata University School of Medicine, Asahimachi-Dori, Niigata 951-8510, Japan
- Department of Virology, Niigata University School of Medicine, Asahimachi-Dori, Niigata 951-8510, Japan
| | - Fatah Kashanchi
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
- The Institute for Genomic Research (TIGR), Rockville, MD 20850, USA
| |
Collapse
|
12
|
Hegde NR, Chevalier MS, Wisner TW, Denton MC, Shire K, Frappier L, Johnson DC. The role of BiP in endoplasmic reticulum-associated degradation of major histocompatibility complex class I heavy chain induced by cytomegalovirus proteins. J Biol Chem 2006; 281:20910-20919. [PMID: 16731524 DOI: 10.1074/jbc.m602989200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Human cytomegalovirus (HCMV1) US11 and US2 proteins cause rapid degradation of major histocompatibility complex (MHC) molecules, apparently by ligating cellular endoplasmic reticulum (ER)-associated degradation machinery. Here, we show that US11 and US2 bind the ER chaperone BiP. Four related HCMV proteins, US3, US7, US9, and US10, which do not promote degradation of MHC proteins, did not bind BiP. Silencing BiP reduced US11- and US2-mediated degradation of MHC class I heavy chain (HC) without altering the synthesis or translocation of HC into the ER or the stability of HC in the absence of US11 or US2. Induction of the unfolded protein response (UPR) did not affect US11-mediated HC degradation and could not explain the stabilization of HC when BiP was silenced. Unlike in yeast, BiP did not act by maintaining substrates in a retrotranslocation-competent form. Our studies go beyond previous observations in mammalian cells correlating BiP release with degradation, demonstrating that BiP is functionally required for US2- and US11-mediated HC degradation. Further, US2 and US11 bound BiP even when HC was absent and degradation of US2 depended on HC. These data were consistent with a model in which US2 and US11 bridge HC onto BiP promoting interactions with other ER-associated degradation proteins.
Collapse
Affiliation(s)
- Nagendra R Hegde
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239
| | - Mathieu S Chevalier
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239
| | - Todd W Wisner
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239
| | - Michael C Denton
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239
| | - Kathy Shire
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Lori Frappier
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - David C Johnson
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239.
| |
Collapse
|
13
|
Lilley BN, Ploegh HL. Viral modulation of antigen presentation: manipulation of cellular targets in the ER and beyond. Immunol Rev 2005; 207:126-44. [PMID: 16181332 DOI: 10.1111/j.0105-2896.2005.00318.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Viruses that establish long-term infections in their hosts have evolved a number of methods to interfere with the activities of the innate and adaptive immune systems. Control of viral infections is achieved in part through the action of cytotoxic T lymphocytes (CTLs) that recognize cytosolically derived antigenic peptides in the context of class I major histocompatibility complex (MHC) molecules. Viral replication within host cells produces abundant proteinaceous fodder for proteasomal digestion and display by class I MHC products. Tactics that disrupt antigen-presentation pathways and prevent the display of peptides to CD8(+) CTLs have been favored during the course of host-virus co-evolution. Viral immunoevasins exploit diverse cellular processes to interfere with host antiviral functions. The study of such viral factors has uncovered novel host proteins that assist these viral factors in their task and that themselves perform important cellular functions. Here, we focus on viral immunoevasins that, together with their cellular targets, interfere with antigen-presentation pathways. In particular, we emphasize the intersection of the cellular quality-control machinery in the endoplasmic reticulum with the herpesvirus proteins that have co-opted it.
Collapse
Affiliation(s)
- Brendan N Lilley
- Department of Pathology, Harvard Medical School, Boston, MA, USA.
| | | |
Collapse
|
14
|
Pande NT, Powers C, Ahn K, Früh K. Rhesus cytomegalovirus contains functional homologues of US2, US3, US6, and US11. J Virol 2005; 79:5786-98. [PMID: 15827193 PMCID: PMC1082751 DOI: 10.1128/jvi.79.9.5786-5798.2005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Accepted: 12/16/2004] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a paradigm for mechanisms subverting antigen presentation by major histocompatibility complex (MHC) molecules. Due to its limited host range, HCMV cannot be studied in animals. Thus, the in vivo importance of inhibiting antigen presentation for the establishment and maintenance of infection with HCMV is unknown. Rhesus cytomegalovirus (RhCMV) is an emerging animal model that shares many of the features of HCMV infection. The recent completion of the genomic sequence of RhCMV revealed a significant degree of homology to HCMV. Strikingly, RhCMV contains several genes with low homology to the HCMV US6 gene family of inhibitors of the MHC I antigen presentation pathway. Here, we examine whether the RhCMV US6 homologues (open reading frames Rh182, -184, -185, -186, -187, and -189) interfere with the MHC I antigen-processing pathway. We demonstrate that Rh182 and Rh189 function similarly to HCMV US2 and US11, respectively, mediating the proteasomal degradation of newly synthesized MHC I. The US3 homologue, Rh184, delayed MHC I maturation. Unlike US3, MHC I molecules eventually escaped retention by Rh184, so that steady-state surface levels of MHC I remained unchanged. Rh185 acted similarly to US6 and inhibited peptide transport by TAP and, consequently, peptide loading of MHC I molecules. Thus, despite relatively low sequence conservation, US6 family-related genes in RhCMV are functionally closely related to the conserved structural features of HCMV immunomodulators. The conservation of these mechanisms implies their importance for immune evasion in vivo, a question that can now be addressed experimentally.
Collapse
Affiliation(s)
- Nupur T Pande
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 NW 185th Ave., Beaverton, OR 97006, USA
| | | | | | | |
Collapse
|
15
|
Wang X, Connors R, Harris MR, Hansen TH, Lybarger L. Requirements for the selective degradation of endoplasmic reticulum-resident major histocompatibility complex class I proteins by the viral immune evasion molecule mK3. J Virol 2005; 79:4099-108. [PMID: 15767411 PMCID: PMC1061547 DOI: 10.1128/jvi.79.7.4099-4108.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recent studies suggest that certain viral proteins co-opt endoplasmic reticulum (ER) degradation pathways to prevent the surface display of major histocompatibility complex class I molecules to the immune system. A novel example of such a molecule is the mK3 protein of gammaherpesvirus 68. mK3 belongs to an extensive family of structurally similar viral and cellular proteins that function as ubiquitin ligases using a conserved RING-CH domain. In the specific case of mK3, it selectively targets the rapid degradation of nascent class I heavy chains in the ER while they are associated with the class I peptide-loading complex (PLC). We present here evidence that the PLC imposes a relative proximity and/or orientation on the RING-CH domain of mK3 that is required for it to specifically target class I molecules for degradation. Furthermore, we demonstrate that full assembly of class I molecules with peptide is not a prerequisite for mK3-mediated degradation. Surprisingly, although the cytosolic tail of class I is required for rapid mK3-mediated degradation, we observed that a class I mutant lacking lysine residues in its cytosolic tail was ubiquitinated and degraded in the presence of mK3 in a manner indistinguishable from wild-type class I molecules. These findings are consistent with a "partial dislocation" model for turnover of ER proteins and define some common features of ER degradation pathways initiated by structurally distinct herpesvirus proteins.
Collapse
Affiliation(s)
- Xiaoli Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | | | | | | |
Collapse
|
16
|
Gnann A, Riordan JR, Wolf DH. Cystic fibrosis transmembrane conductance regulator degradation depends on the lectins Htm1p/EDEM and the Cdc48 protein complex in yeast. Mol Biol Cell 2004; 15:4125-35. [PMID: 15215312 PMCID: PMC515346 DOI: 10.1091/mbc.e04-01-0024] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 05/13/2004] [Accepted: 06/08/2004] [Indexed: 11/11/2022] Open
Abstract
Cystic fibrosis is the most widespread hereditary disease among the white population caused by different mutations of the apical membrane ATP-binding cassette transporter cystic fibrosis transmembrane conductance regulator (CFTR). Its most common mutation, DeltaF508, leads to nearly complete degradation via endoplasmic reticulum-associated degradation (ERAD). Elucidation of the quality control and degradation mechanisms might give rise to new therapeutic approaches to cure this disease. In the yeast Saccharomyces cerevisiae, a variety of components of the protein quality control and degradation system have been identified. Nearly all of these components share homology with mammalian counterparts. We therefore used yeast mutants defective in the ERAD system to identify new components that are involved in human CFTR quality control and degradation. We show the role of the lectin Htm1p in the degradation process of CFTR. Complementation of the HTM1 deficiency in yeast cells by the mammalian orthologue EDEM underlines the necessity of this lectin for CFTR degradation and highlights the similarity of quality control and ERAD in yeast and mammals. Furthermore, degradation of CFTR requires the ubiquitin protein ligases Der3p/Hrd1p and Doa10p as well as the cytosolic trimeric Cdc48p-Ufd1p-Npl4p complex. These proteins also were found to be necessary for ERAD of a mutated yeast "relative" of CFTR, Pdr5(*)p.
Collapse
Affiliation(s)
- Andreas Gnann
- Institut für Biochemie, Universität Stuttgart, 70569 Stuttgart, Germany
| | | | | |
Collapse
|
17
|
Petersen JL, Morris CR, Solheim JC. Virus evasion of MHC class I molecule presentation. THE JOURNAL OF IMMUNOLOGY 2004; 171:4473-8. [PMID: 14568919 DOI: 10.4049/jimmunol.171.9.4473] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jason L Petersen
- Eppley Institute for Research in Cancer and Allied Diseases, Omaha, NE 68198-6805, USA
| | | | | |
Collapse
|
18
|
Abstract
Presumably because of the selective pressure exerted by the immune system, many viruses have evolved proteins that interfere with antigen presentation by major histocompatibility complex (MHC) class I molecules. These viruses utilize a whole variety of ingenious strategies to inhibit the MHC class I pathway. Viral proteins have been characterized that exploit bottlenecks in the MHC class I pathway, such as peptide translocation by the transporter associated with antigen processing. Alternatively, viral proteins can cause the degradation or mislocalization of MHC class I molecules. This is often achieved by the subversion of the host cell's own protein degradation and trafficking pathways. As a consequence elucidation of how these viral proteins act to subvert host cell function will continue to give important insights not only into virus-host interactions but also the function and mechanism of cellular pathways.
Collapse
Affiliation(s)
- Eric W Hewitt
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds, UK.
| |
Collapse
|
19
|
Hegde NR, Johnson DC. Human cytomegalovirus US2 causes similar effects on both major histocompatibility complex class I and II proteins in epithelial and glial cells. J Virol 2003; 77:9287-94. [PMID: 12915544 PMCID: PMC187418 DOI: 10.1128/jvi.77.17.9287-9294.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) glycoprotein US2 specifically binds to major histocompatibility complex (MHC) class I heavy chain (HC) and class II proteins DRalpha and DMalpha, triggering their degradation by proteasomes. Effects of US2 on class II proteins were originally characterized in HCMV- or adenovirus vector-infected U373 astroglioma cells. Here, we have extended characterization of US2-mediated degradation of class II DRalpha to two other cell lines, including biologically relevant epithelial cells. Comparison of the effects of US2 in cells expressing both class I and II proteins demonstrated only a slight preference for class I HC. Moreover, US2 caused degradation of DRalpha and DMalpha when these proteins were expressed by transfection without DRbeta, invariant chain (Ii), or DMbeta. Therefore, US2 binds to alpha chains of DR and DM and triggers endoplasmic reticulum degradation without formation of class II DR alphabeta/Ii or DM alphabeta complexes. Similar levels of degradation of class II alpha were observed in cells expressing vastly different amounts of class II, suggesting that cellular factors, other than class II, were limiting. We concluded that US2 has broad effects in a variety of cells that express both class I and II proteins and is relevant to HCMV infection in vivo.
Collapse
Affiliation(s)
- Nagendra R Hegde
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon 97239-3098, USA
| | | |
Collapse
|