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Miller WE, O'Connor CM. CMV-encoded GPCRs in infection, disease, and pathogenesis. Adv Virus Res 2024; 118:1-75. [PMID: 38461029 DOI: 10.1016/bs.aivir.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2024]
Abstract
G protein coupled receptors (GPCRs) are seven-transmembrane domain proteins that modulate cellular processes in response to external stimuli. These receptors represent the largest family of membrane proteins, and in mammals, their signaling regulates important physiological functions, such as vision, taste, and olfaction. Many organisms, including yeast, slime molds, and viruses encode GPCRs. Cytomegaloviruses (CMVs) are large, betaherpesviruses, that encode viral GPCRs (vGPCRs). Human CMV (HCMV) encodes four vGPCRs, including UL33, UL78, US27, and US28. Each of these vGPCRs, as well as their rodent and primate orthologues, have been investigated for their contributions to viral infection and disease. Herein, we discuss how the CMV vGPCRs function during lytic and latent infection, as well as our understanding of how they impact viral pathogenesis.
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Affiliation(s)
- William E Miller
- Department of Molecular and Cellular Bioscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christine M O'Connor
- Infection Biology, Sheikha Fatima bint Mubarak Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, OH, United States; Case Comprehensive Cancer Center, Cleveland, OH, United States.
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Murine cytomegalovirus degrades MHC class II to colonize the salivary glands. PLoS Pathog 2018; 14:e1006905. [PMID: 29447285 PMCID: PMC5831752 DOI: 10.1371/journal.ppat.1006905] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 02/28/2018] [Accepted: 01/24/2018] [Indexed: 12/24/2022] Open
Abstract
Cytomegaloviruses (CMVs) persistently and systemically infect the myeloid cells of immunocompetent hosts. Persistence implies immune evasion, and CMVs evade CD8+ T cells by inhibiting MHC class I-restricted antigen presentation. Myeloid cells can also interact with CD4+ T cells via MHC class II (MHC II). Human CMV (HCMV) attacks the MHC II presentation pathway in vitro, but what role this evasion might play in host colonization is unknown. We show that Murine CMV (MCMV) down-regulates MHC II via M78, a multi-membrane spanning viral protein that captured MHC II from the cell surface and was necessary although not sufficient for its degradation in low pH endosomes. M78-deficient MCMV down-regulated MHC I but not MHC II. After intranasal inoculation, it showed a severe defect in salivary gland colonization that was associated with increased MHC II expression on infected cells, and was significantly rescued by CD4+ T cell loss. Therefore MCMV requires CD4+ T cell evasion by M78 to colonize the salivary glands, its main site of long-term shedding. Human cytomegalovirus is the commonest infectious cause of harm to unborn children. Vaccines have not stopped it establishing chronic, systemic infections. Murine cytomegalovirus (MCMV) provides an accessible model to understand why. We show that MCMV evades CD4+ T cells via its M78 protein, and that this helps infection to spread despite the immune response. Thus while CD4+ T cells are important for host defence, viral evasion limits their capacity to act alone in controlling infection.
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Bagam P, Singh DP, Inda ME, Batra S. Unraveling the role of membrane microdomains during microbial infections. Cell Biol Toxicol 2017; 33:429-455. [PMID: 28275881 PMCID: PMC7088210 DOI: 10.1007/s10565-017-9386-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/06/2017] [Indexed: 01/06/2023]
Abstract
Infectious diseases pose major socioeconomic and health-related threats to millions of people across the globe. Strategies to combat infectious diseases derive from our understanding of the complex interactions between the host and specific bacterial, viral, and fungal pathogens. Lipid rafts are membrane microdomains that play important role in life cycle of microbes. Interaction of microbial pathogens with host membrane rafts influences not only their initial colonization but also their spread and the induction of inflammation. Therefore, intervention strategies aimed at modulating the assembly of membrane rafts and/or regulating raft-directed signaling pathways are attractive approaches for the. management of infectious diseases. The current review discusses the latest advances in terms of techniques used to study the role of membrane microdomains in various pathological conditions and provides updated information regarding the role of membrane rafts during bacterial, viral and fungal infections.
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Affiliation(s)
- Prathyusha Bagam
- Laboratory of Pulmonary Immuno-Toxicology, Department of Environmental Toxicology, Health Research Center, Southern University and A&M College, Baton Rouge, LA, 70813, USA
| | - Dhirendra P Singh
- Laboratory of Pulmonary Immuno-Toxicology, Department of Environmental Toxicology, Health Research Center, Southern University and A&M College, Baton Rouge, LA, 70813, USA
| | - Maria Eugenia Inda
- Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Suipacha, Rosario, Argentina
| | - Sanjay Batra
- Laboratory of Pulmonary Immuno-Toxicology, Department of Environmental Toxicology, Health Research Center, Southern University and A&M College, Baton Rouge, LA, 70813, USA.
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The Cytoplasmic C-Tail of the Mouse Cytomegalovirus 7 Transmembrane Receptor Homologue, M78, Regulates Endocytosis of the Receptor and Modulates Virus Replication in Different Cell Types. PLoS One 2016; 11:e0165066. [PMID: 27760189 PMCID: PMC5070858 DOI: 10.1371/journal.pone.0165066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/05/2016] [Indexed: 12/03/2022] Open
Abstract
Virus homologues of seven-transmembrane receptors (7TMR) are encoded by all beta- and gammaherpesviruses, suggesting important functional roles. M78 of mouse cytomegalovirus (MCMV) is representative of a family of 7TMR conserved in all betaherpesviruses. M78 family members have been found to exhibit cell-type specific effects upon virus replication in tissue culture and to affect virus pathogenesis in vivo. We reported previously that M78, for which no ligands are known, undergoes rapid, constitutive endocytosis. In this study, we have investigated the role of the M78 cytoplasmic C-tail in mediating endocytosis and consequences of C-tail deletion upon replication and pathogenesis. Mutations of M78 (C-tail truncations or point mutations) and CCR5-M78 chimeras identified two distinct regions affecting endocytosis. The first was a classical acidic di-leucine motif (DDxxxLL), located close to the C-terminus. The second region, the activity of which was suppressed by downstream sequences, included the putative 8th helix, located close to the 7th transmembrane domain. A recombinant MCMV expressing an endocytosis-deficient M78, lacking most of the C-tail (M78_CΔ155), had a cell-type specific replication phenotype. M78_CΔ155 had restricted replication in bone marrow macrophages, indistinguishable from an M78-null recombinant. In contrast, M78_CΔ155 replicated normally or with enhanced titres to wild type virus in other tested cell-types, whereas M78-null was attenuated. Distinct phenotypes for M78_CΔ155 and M78-null suggest that the C-tail deletion resulted in M78 dysfunction, rather than complete loss of function; furthermore, they highlight a cell-type specific role of M78 during replication. Infection of mice (intranasal) demonstrated that M78_CΔ155, similar to M78-null, was cleared more rapidly from the lungs than wild type virus and was severely attenuated for replication in salivary glands. It may be speculated that attenuation of both M78_CΔ155 and M78-null for replication in macrophages may have contributed to their similar pathogenic phenotypes.
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Mølleskov-Jensen AS, Oliveira MT, Farrell HE, Davis-Poynter N. Virus-Encoded 7 Transmembrane Receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 129:353-93. [DOI: 10.1016/bs.pmbts.2014.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Niemann I, Reichel A, Stamminger T. Intracellular trafficking of the human cytomegalovirus-encoded 7-trans-membrane protein homologs pUS27 and pUL78 during viral infection: a comparative analysis. Viruses 2014; 6:661-82. [PMID: 24517969 PMCID: PMC3939477 DOI: 10.3390/v6020661] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/09/2014] [Accepted: 01/13/2014] [Indexed: 12/23/2022] Open
Abstract
Human cytomegalovirus (HCMV) encodes four G protein-coupled receptor (GPCR) homologs, termed pUS27, pUS28, pUL33, and pUL78. In contrast to the extensively characterized vGPCRs pUS28 and pUL33, knowledge concerning pUS27 and pUL78 is limited. Previous studies already demonstrated constitutive internalization of pUS27 and pUL78, as well as an association with the endosomal machinery, however, these results were mainly obtained using transiently transfected cells. To explore the subcellular localization of both receptors during viral infection, we constructed recombinant HCMVs expressing tagged vGPCRs. Colocalization analyses revealed a predominant association of pUS27 or pUL78 with the trans-Golgi network or the endoplasmic reticulum, respectively. Intriguingly, our data emphasize that protein sorting is highly regulated by viral functions as we detected dramatic changes in the colocalization of pUS27 and pUL78 with endosomal markers during progression of HCMV replication. Furthermore, we observed cell type-dependent differences in trafficking of both vGPCRs between fibroblasts and epithelial cells. Most importantly, infection experiments with a recombinant HCMV carrying tagged versions of pUS27 and pUL78 simultaneously, revealed that these two proteins do not colocalize during viral infection. This contrasts to results of transient expression experiments. In conclusion, our results highlight the importance to investigate vGPCR trafficking in a viral context.
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Affiliation(s)
- Ina Niemann
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Schlossgarten 4, Erlangen 91054, Germany.
| | - Anna Reichel
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Schlossgarten 4, Erlangen 91054, Germany.
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Schlossgarten 4, Erlangen 91054, Germany.
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Identification of common mechanisms by which human and mouse cytomegalovirus seven-transmembrane receptor homologues contribute to in vivo phenotypes in a mouse model. J Virol 2013; 87:4112-7. [PMID: 23345521 DOI: 10.1128/jvi.03406-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The mouse cytomegalovirus chemokine receptor homologue (CKR) M33 is required for salivary gland tropism and efficient reactivation from latency, phenotypes partially rescued by the human cytomegalovirus CKR US28. Herein, we demonstrate that complementation of salivary gland tropism is mediated predominantly by G protein-dependent signaling conserved with that of M33; in contrast, both G protein-dependent and -independent pathways contribute to the latency phenotypes. A novel M33-dependent replication phenotype in cultured bone marrow macrophages is also described.
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Jockers R, Gbahou F, Tadagaki K, Kamal M. Oligomérisation des protéines humaines et virales à sept domaines transmembranaires. Med Sci (Paris) 2012; 28:864-9. [DOI: 10.1051/medsci/20122810015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Stapleton LK, Arnolds KL, Lares AP, Devito TM, Spencer JV. Receptor chimeras demonstrate that the C-terminal domain of the human cytomegalovirus US27 gene product is necessary and sufficient for intracellular receptor localization. Virol J 2012; 9:42. [PMID: 22339884 PMCID: PMC3298792 DOI: 10.1186/1743-422x-9-42] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 02/16/2012] [Indexed: 11/15/2022] Open
Abstract
Background Human cytomegalovirus (HCMV) is ubiquitous in the population but generally causes only mild or asymptomatic infection except in immune suppressed individuals. HCMV employs numerous strategies for manipulating infected cells, including mimicry of G-protein coupled receptors (GPCRs). The HCMV US27 gene product is a putative GPCR, yet no ligand or signaling has been identified for this receptor. In the present study, immunofluorescence microscopy was used to examine the cellular distribution of wild type US27, as well as US27 deletion mutants and chimeric receptors. Results In transiently transfected cells, wild type US27 was found primarily in intracellular compartments, in striking contrast to the cell surface distribution seen for the human cellular chemokine receptor CXCR3. When the N-terminal extracellular domains of the two receptors were swapped, no change in protein localization was observed. However, swapping of the C-terminal intracellular domains resulted in a significant change in receptor distribution. A chimera that contained US27 fused to the C-terminal intracellular tail of CXCR3 exhibited surface distribution similar to that of wild-type CXCR3. When the C-terminal domain of US27 was fused to CXCR3, this chimeric receptor (CXCR3/US27-CT) was found in the same intracellular pattern as wild-type US27. In addition, a US27 mutant lacking the C-terminus (US27ΔCT) failed to accumulate inside the cell and exhibited cell surface distribution. Co-localization with organelle-specific markers revealed that wild-type US27 was found predominantly in the Golgi apparatus and in endosomal compartments, whereas the US27/CXCR3-CT chimera, US27ΔCT and US27Δ348 mutants were not localized to endosomal compartments. Conclusions The results indicate that the C-terminal domain of the HCMV US27 protein, which contains a di-leucine endocytic sorting motif, is both necessary and sufficient for intracellular localization, which may also help explain why no cellular ligands have yet been identified for this viral receptor.
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Wagner S, Arnold F, Wu Z, Schubert A, Walliser C, Tadagaki K, Jockers R, Mertens T, Michel D. The 7-transmembrane protein homologue UL78 of the human cytomegalovirus forms oligomers and traffics between the plasma membrane and different intracellular compartments. Arch Virol 2012; 157:935-49. [PMID: 22327422 DOI: 10.1007/s00705-012-1246-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 12/29/2011] [Indexed: 12/22/2022]
Abstract
The human cytomegalovirus (HCMV) UL78 ORF is considered to encode an orphan 7-transmembrane receptor. However, until now, the UL78 protein (pUL78) has not been characterized. Here, we have investigated the expression of pUL78 and found it mainly associated with the endoplasmic reticulum. However, we provide evidence that pUL78 is also localized on the cell surface from where it is quickly endocytosed. Colocalization with adaptin and EEA-1 implies that at least a small amount of pUL78 is transported to the trans Golgi network and early endosomes. Using a bimolecular fluorescence complementation assay and co-immunoprecipitation experiments, we were able to find homomeric and heteromeric structure formations of pUL78 and the US28 protein, respectively. However, the absence of pUL78 had no effect on the accumulation of inositol phosphate triggered by the US28 protein. In summary, our results suggest that the UL78 protein of HCMV traffics between the cell surface and cytoplasm, from where it might be recycled via early endosomes.
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Affiliation(s)
- Svenja Wagner
- Institut für Virologie, Universitätsklinikum Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Function of membrane rafts in viral lifecycles and host cellular response. Biochem Res Int 2011; 2011:245090. [PMID: 22191032 PMCID: PMC3235436 DOI: 10.1155/2011/245090] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 08/31/2011] [Accepted: 09/27/2011] [Indexed: 12/31/2022] Open
Abstract
Membrane rafts are small (10–200 nm) sterol- and sphingolipid-enriched domains that compartmentalize cellular processes. Membrane rafts play an important role in viral infection cycles and viral virulence. Viruses are divided into four main classes, enveloped DNA virus, enveloped RNA virus, nonenveloped DNA virus, and nonenveloped RNA virus. General virus infection cycle is also classified into two sections, the early stage (entry process) and the late stage (assembly, budding, and release processes of virus particles). In the viral cycle, membrane rafts act as a scaffold of many cellular signal transductions, which are associated with symptoms caused by viral infections. In this paper, we describe the functions of membrane rafts in viral lifecycles and host cellular response according to each virus classification, each stage of the virus lifecycle, and each virus-induced signal transduction.
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Lacaze P, Forster T, Ross A, Kerr LE, Salvo-Chirnside E, Lisnic VJ, López-Campos GH, García-Ramírez JJ, Messerle M, Trgovcich J, Angulo A, Ghazal P. Temporal profiling of the coding and noncoding murine cytomegalovirus transcriptomes. J Virol 2011; 85:6065-76. [PMID: 21471238 PMCID: PMC3126304 DOI: 10.1128/jvi.02341-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 03/28/2011] [Indexed: 12/20/2022] Open
Abstract
The global transcriptional program of murine cytomegalovirus (MCMV), involving coding, noncoding, and antisense transcription, remains unknown. Here we report an oligonucleotide custom microarray platform capable of measuring both coding and noncoding transcription on a genome-wide scale. By profiling MCMV wild-type and immediate-early mutant strains in fibroblasts, we found rapid activation of the transcriptome by 6.5 h postinfection, with absolute dependency on ie3, but not ie1 or ie2, for genomic programming of viral gene expression. Evidence is also presented to show, for the first time, genome-wide noncoding and bidirectional transcription at late stages of MCMV infection.
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Affiliation(s)
- Paul Lacaze
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
| | - Thorsten Forster
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
| | - Alan Ross
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
| | - Lorraine E. Kerr
- Centre for Systems Biology at Edinburgh, The University of Edinburgh, Darwin Building, King's Buildings Campus, Mayfield Road, Edinburgh, United Kingdom
| | - Eliane Salvo-Chirnside
- Centre for Systems Biology at Edinburgh, The University of Edinburgh, Darwin Building, King's Buildings Campus, Mayfield Road, Edinburgh, United Kingdom
| | - Vanda Juranic Lisnic
- Department of Histology and Embryology, Faculty of Medicine, Rijeka University, Croatia
| | | | - José J. García-Ramírez
- Department of Inorganic and Organic Chemistry and Biochemistry, Medical School, Regional Center for Biomedical Research, University of Castilla—La Mancha, Avenida de Almansa 14, 02006 Albacete, Spain
| | - Martin Messerle
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Joanne Trgovcich
- Department of Pathology, The Ohio State University, Columbus, Ohio 43210
| | - Ana Angulo
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Peter Ghazal
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
- Centre for Systems Biology at Edinburgh, The University of Edinburgh, Darwin Building, King's Buildings Campus, Mayfield Road, Edinburgh, United Kingdom
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