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Joseph J, Premeaux TA, Tandon R, Murphy EL, Bruhn R, Nicot C, Herrera BB, Lemenze A, Alatrash R, Baffour Tonto P, Ndhlovu LC, Jain P. Dendritic Cells Pulsed with HAM/TSP Exosomes Sensitize CD4 T Cells to Enhance HTLV-1 Infection, Induce Helper T-Cell Polarization, and Decrease Cytotoxic T-Cell Response. Viruses 2024; 16:1443. [PMID: 39339919 PMCID: PMC11436225 DOI: 10.3390/v16091443] [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] [Received: 08/15/2024] [Revised: 09/05/2024] [Accepted: 09/08/2024] [Indexed: 09/30/2024] Open
Abstract
HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a progressive demyelinating disease of the spinal cord due to chronic inflammation. Hallmarks of disease pathology include dysfunctional anti-viral responses and the infiltration of HTLV-1-infected CD4+ T cells and HTLV-1-specific CD8+ T cells in the central nervous system. HAM/TSP individuals exhibit CD4+ and CD8+ T cells with elevated co-expression of multiple inhibitory immune checkpoint proteins (ICPs), but ICP blockade strategies can only partially restore CD8+ T-cell effector function. Exosomes, small extracellular vesicles, can enhance the spread of viral infections and blunt anti-viral responses. Here, we evaluated the impact of exosomes isolated from HTLV-1-infected cells and HAM/TSP patient sera on dendritic cell (DC) and T-cell phenotypes and function. We observed that exosomes derived from HTLV-infected cell lines (OSP2) elicit proinflammatory cytokine responses in DCs, promote helper CD4+ T-cell polarization, and suppress CD8+ T-cell effector function. Furthermore, exosomes from individuals with HAM/TSP stimulate CD4+ T-cell polarization, marked by increased Th1 and regulatory T-cell differentiation. We conclude that exosomes in the setting of HAM/TSP are detrimental to DC and T-cell function and may contribute to the progression of pathology with HTLV-1 infection.
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Affiliation(s)
- Julie Joseph
- Department of Microbiology & Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Thomas A Premeaux
- Department of Medicine, Division of Infectious Diseases, Weill Cornel Medicine, New York, NY 10021, USA
| | - Ritesh Tandon
- Department of Microbiology & Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Edward L Murphy
- Departments of Laboratory Medicine and Epidemiology/Biostatistics, University of California, San Francisco, CA 94143, USA
- Vitalant Research Institute, San Francisco, CA 94105, USA
| | - Roberta Bruhn
- Vitalant Research Institute, San Francisco, CA 94105, USA
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66103, USA
| | - Bobby Brooke Herrera
- Rutgers Global Health Institute, Rutgers University, Newark, NJ 07102, USA
- Department of Medicine, Division of Allergy, Immunology, and Infectious Diseases, and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Alexander Lemenze
- Molecular and Genomics Informatics Core, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Reem Alatrash
- Rutgers Global Health Institute, Rutgers University, Newark, NJ 07102, USA
- Department of Medicine, Division of Allergy, Immunology, and Infectious Diseases, and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Prince Baffour Tonto
- Rutgers Global Health Institute, Rutgers University, Newark, NJ 07102, USA
- Department of Medicine, Division of Allergy, Immunology, and Infectious Diseases, and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Lishomwa C Ndhlovu
- Department of Medicine, Division of Infectious Diseases, Weill Cornel Medicine, New York, NY 10021, USA
| | - Pooja Jain
- Department of Microbiology & Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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Joseph J, Premeaux TA, Pinto DO, Rao A, Guha S, Panfil AR, Carey AJ, Ndhlovu LC, Bergmann‐Leitner ES, Jain P. Retroviral b-Zip protein (HBZ) contributes to the release of soluble and exosomal immune checkpoint molecules in the context of neuroinflammation. JOURNAL OF EXTRACELLULAR BIOLOGY 2023; 2:e102. [PMID: 37547182 PMCID: PMC10399615 DOI: 10.1002/jex2.102] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/13/2023] [Accepted: 07/01/2023] [Indexed: 08/08/2023]
Abstract
HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive, neuroinflammatory demyelinating condition of the spinal cord. We have previously shown that aberrant expression and activity of immune checkpoint (ICP) molecules such as PD-1 and PD-L1/PD-L2, negatively associates with the cytolytic potential of T cells in individuals with HAM/TSP. Interestingly, ICPs can exist in a soluble cell-free form and can be carried on extracellular vesicles (EVs) and exosomes (small EVs, <300nm) while maintaining their immunomodulatory activity. Therefore, we investigated the role of soluble and exosomal ICPs in HTLV-1 associated neuroinflammation. For the very first time, we demonstrate a unique elevated presence of several stimulatory (CD27, CD28, 4-1BB) and inhibitory (BTLA, CTLA-4, LAG-3, PD-1, PD-L2) ICP receptors in HAM/TSP sera, and in purified exosomes from a HAM/TSP-derived HTLV-1-producing (OSP2) cells. These ICPs were found to be co-localized with the endosomal sorting complex required for transport (ESCRT) pathway proteins and exhibited functional binding with their respective ligands. Viral proteins and cytokines (primarily IFNγ) were found to be present in purified exosomes. IFNγ exposure enhanced the release of ICP molecules while antiretroviral drugs (Azidothymidine and Lopinavir) significantly inhibited this process. HTLV-1 b-Zip protein (HBZ) has been linked to factors that enhance EV release and concurrent knockdown here led to the reduced expression of ESCRT associated genes (eg. Hrs, Vsp4, Alix, Tsg101) as well as abrogated the release of ICP molecules, suggesting HBZ involvement in this process. Moreso, exosomes from OSP2 cells adversely affected CD8 T-cell functions by dimishing levels of cytokines and cytotoxic factors. Collectively, these findings highlight exosome-mediated immunmodulation of T-cell functions with HBZ and ESCRT pathways as an underlying mechanism in the context of HTLV-1-induced neuroinflammation.
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Affiliation(s)
- Julie Joseph
- Department of Microbiology & ImmunologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Thomas A. Premeaux
- Weill Cornel Medicine Department of MedicineDivision of Infectious DiseasesNew YorkNYUSA
| | - Daniel O. Pinto
- Immunology Core, Biologics Research and DevelopmentWalter Reed Army Institute of ResearchSilver SpringsMDUSA
- Oak Ridge Institute for Science and EducationOak RidgeTNUSA
| | - Abhishek Rao
- Department of Microbiology & ImmunologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Shrobona Guha
- Department of Neurobiology and AnatomyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Amanda R. Panfil
- The Ohio State University, College of Veterinary Medicine, Center for Retrovirus ResearchColumbusOhioUSA
| | - Alison J. Carey
- Department of Microbiology & ImmunologyDrexel University College of MedicinePhiladelphiaPAUSA
- Department of PediatricsDrexel University College of MedicinePhiladelphiaPAUSA
| | - Lishomwa C. Ndhlovu
- Weill Cornel Medicine Department of MedicineDivision of Infectious DiseasesNew YorkNYUSA
| | - Elke S. Bergmann‐Leitner
- Immunology Core, Biologics Research and DevelopmentWalter Reed Army Institute of ResearchSilver SpringsMDUSA
| | - Pooja Jain
- Department of Microbiology & ImmunologyDrexel University College of MedicinePhiladelphiaPAUSA
- Department of Neurobiology and AnatomyDrexel University College of MedicinePhiladelphiaPAUSA
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3
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Accolla RS. The Road to HTLV-1-Induced Leukemia by Following the Subcellular Localization of HTLV-1-Encoded HBZ Protein. Front Immunol 2022; 13:940131. [PMID: 35812456 PMCID: PMC9259882 DOI: 10.3389/fimmu.2022.940131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Human T cell leukemia virus-1 (HTLV-1) is the causative agent of a severe cancer of the lymphoid lineage that develops in 3-5% of infected individuals after many years. HTLV-1 infection may also induce a serious inflammatory pathology of the nervous system designated HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Two virus-encoded proteins, the viral transactivator Tax-1 and the HTLV-1 basic leucine-zipper factor HBZ, are strongly involved in the oncogenic process. Tax-1 is involved in initial phases of the oncogenic process. Conversely, HBZ seems to be involved in maintenance of the neoplastic state as witnessed by the generation of leukemic/lymphomatous phenotype in HBZ transgenic mice and the persistent expression of HBZ in all phases of the oncogenic process. Nevertheless, the intimate molecular and cellular mechanism mediated by the two viral proteins, particularly HBZ, in oncogenesis still remain elusive. An important step toward the complete comprehension of HBZ-associated oncogenicity is the clarification of the anatomical correlates of HBZ during the various phases of HTLV-1 infection to development of HTLV-1-associated inflammatory pathology and ultimately to the establishment of leukemia. In this review, I will summarize recent studies that have established for the first time a temporal and unidirectional expression of HBZ, beginning with an exclusive cytoplasmic localization in infected asymptomatic individuals and in HAM/TSP patients and ending to a progressive cytoplasmic-to-nuclear transition in leukemic cells. These results are framed within the present knowledge of HTLV-1 infection and the future lines of research that may shed new light on the complex mechanism of HTLV-1- mediated oncogenesis.
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Lin E, Panfil AR, Sandel G, Jain P. Novel perspectives on antisense transcription in HIV-1, HTLV-1, and HTLV-2. Front Microbiol 2022; 13:1042761. [PMID: 36620051 PMCID: PMC9822710 DOI: 10.3389/fmicb.2022.1042761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/24/2022] [Indexed: 12/25/2022] Open
Abstract
The genome of retroviruses contains two promoter elements (called long terminal repeat or LTR) at the 5' and 3' end of their genome. Although the expression of retroviral genes generally depends on the promoter located in the 5' LTR, the 3' LTR also has promoter activity responsible for producing antisense transcripts. These natural antisense transcripts (NATs) are a class of RNA molecules transcribed from the opposite strand of a protein-coding gene. NATs have been identified in many prokaryotic and eukaryotic systems, as well as in human retroviruses such as human immunodeficiency virus type 1 (HIV-1) and HTLV-1/2 (human T-cell leukemia virus type 1/2). The antisense transcripts of HIV-1, HTLV-1, and HTLV-2 have been briefly characterized over the past several years. However, a complete appreciation of the role these transcripts play in the virus lifecycle and the cellular factors which regulate their transcription is still lacking. This review provides an overview of antisense transcription in human retroviruses with a specific focus on the MEF-2 family of transcription factors, the function(s) of the antisense protein products, and the application of antisense transcription models in therapeutics against HIV-1 and HTLV-1 in the context of co-infection.
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Affiliation(s)
- Edward Lin
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Amanda R. Panfil
- Department of Veterinary Biosciences, Center for Retrovirus Research, The Ohio State University, Columbus, OH, United States
| | - Grace Sandel
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Pooja Jain
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- *Correspondence: Pooja Jain,
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Forlani G, Shallak M, Tedeschi A, Cavallari I, Marçais A, Hermine O, Accolla RS. Dual cytoplasmic and nuclear localization of HTLV-1-encoded HBZ protein is a unique feature of adult T-cell leukemia. Haematologica 2021; 106:2076-2085. [PMID: 33626865 PMCID: PMC8327710 DOI: 10.3324/haematol.2020.272468] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 01/28/2023] Open
Abstract
Adult T-cell leukemia-lymphoma (ATL), is a highly malignant T-cell neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1), characterized by poor prognosis. Two viral proteins, Tax-1 and HTLV-1 basic-zipper factor (HBZ) play important roles in the pathogenesis of ATL. While Tax-1 can be found in both the cytoplasm and nucleus of HTLV-1 infected patients, HBZ is exclusively localized in the cytoplasm of HTLV-1 asymptomatic carriers and in patients with the chronic neurologic disease HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HBZ is only localized in the nucleus of ATL cell lines, suggesting that the nuclear localization of HBZ can be a hallmark of neoplastic transformation. In order to clarify this crucial point, we investigated in detail the pattern of HBZ expression in ATL patients. We made use of our monoclonal antibody 4D4-F3, that at present is the only reported reagent, among the few described, able to detect endogenous HBZ by immunofluorescence and confocal microscopy in cells from asymptomatic carriers, HAM/TSP and ATL patients. We found that HBZ is localized both in the cytoplasm and nucleus of cells of ATL patients irrespective of their clinical status, with a strong preference for the cytoplasmic localization. Also Tax-1 is localized in both compartments. As HBZ is exclusively localized in the cytoplasm in asymptomatic carriers and in non-neoplastic pathologies, this finding shows that neoplastic transformation consequent to HTLV-1 infection is accompanied and associated with the capacity of HBZ to translocate to the nucleus, which suggests a role of cytoplasmic-to-nuclear translocation in HTLV-1- mediated oncogenesis.
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Affiliation(s)
- Greta Forlani
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese
| | - Mariam Shallak
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese
| | - Alessandra Tedeschi
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese
| | | | - Ambroise Marçais
- Department of Hematology, Necker-Enfants Malades, University Hospital, Assistance Publique Hopitaux de Paris, Paris Descartes University, Paris
| | - Olivier Hermine
- Department of Hematology, Necker-Enfants Malades, University Hospital, Assistance Publique Hopitaux de Paris, Paris Descartes University, Paris
| | - Roberto S Accolla
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese.
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Human T cell leukemia virus type 1 and Zika virus: tale of two reemerging viruses with neuropathological sequelae of public health concern. J Neurovirol 2019; 25:289-300. [PMID: 30693421 DOI: 10.1007/s13365-019-00720-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/16/2018] [Accepted: 01/03/2019] [Indexed: 01/17/2023]
Abstract
Human T cell leukemia virus type 1 (HTLV-1) and Zika virus (ZIKV) have been considered neglected viruses of low public health concern until recently when incidences of HTLV-1 and ZIKV were observed to be linked to serious immune-related disease and neurological complications. This review will discuss the epidemiology, genomic evolution, virus-host interactions, virulence factors, neuropathological sequelae, and current perspectives of these reemerging viruses. There are no FDA-approved therapeutics or vaccines against these viruses, and as such, it is important for clinical trials to focus on developing vaccines that can induce cell-mediated immune response to confer long-term protective immunity. Furthermore, attention should be paid to reducing the transmission of these viruses through unprotected sex, infected blood during sharing of contaminated needles, donated blood and organs, and vertical transmission from mother to baby via breastfeeding. There is an urgent need to re-evaluate repurposing current antiviral therapies as well as developing novel antiviral agents with enhanced efficacy due to the high morbidity rate associated with these two reemerging chronic viral diseases.
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Cruz-Ramos E, Sandoval-Hernández A, Tecalco-Cruz AC. Differential expression and molecular interactions of chromosome region maintenance 1 and calreticulin exportins in breast cancer cells. J Steroid Biochem Mol Biol 2019; 185:7-16. [PMID: 29981820 DOI: 10.1016/j.jsbmb.2018.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 06/29/2018] [Accepted: 07/04/2018] [Indexed: 12/20/2022]
Abstract
Chromosome region maintenance 1 (CRM-1) and calreticulin (CALR) are two proteins that act as exportins for some nuclear receptors, in addition to other critical functions for cellular homeostasis. In several cancer types, CRM-1 and CALR are upregulated suggesting an imbalance in their functions. However, the regulation of CRM-1 and CALR, and their biological implications, are not completely known. Here, we evaluated the interplay between the levels of CRM-1 and CALR, and estrogen receptor alpha (ERα) status, in breast cancer cells. CRM-1 and CALR were upregulated in mammary tumors relative to normal mammary tissue. Furthermore, the mRNA and protein levels of CRM-1 and CALR were higher in breast cancer cells lacking ERα, in comparison with those that express ERα. Additionally, both proteins were distributed in the nucleus and cytoplasm in the two cell types. Importantly, we identified novel interactions for these exportins. First, we showed an interaction between CRM-1 and CALR, and then we identified that SUN1 and SUN2, two proteins localized in the nuclear envelop, were able to interact specifically with CRM-1, but not CALR. Interestingly, SUN1 and SUN2 expression seemed to be decreased in breast cancer, thereby affecting the interactions of these proteins with CRM-1, and possibly its actions as an exportin. Thus, our data suggest that expression levels for CRM-1 and CALR, the interaction between these exportins, and specific interactions of SUN1 and SUN2 with CRM-1 but not CALR, may be central elements in nucleo-cytoplasmic transport. Furthermore, deregulation of these elements may have serious implications in the progression of breast and other types of cancer.
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Affiliation(s)
- Eduardo Cruz-Ramos
- Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo Postal, México D.F. 04510, Mexico
| | - Antonio Sandoval-Hernández
- Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo Postal, México D.F. 04510, Mexico
| | - Angeles C Tecalco-Cruz
- Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo Postal, México D.F. 04510, Mexico.
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Marziali F, Bugnon Valdano M, Brunet Avalos C, Moriena L, Cavatorta AL, Gardiol D. Interference of HTLV-1 Tax Protein with Cell Polarity Regulators: Defining the Subcellular Localization of the Tax-DLG1 Interaction. Viruses 2017; 9:E355. [PMID: 29168728 PMCID: PMC5744130 DOI: 10.3390/v9120355] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/15/2017] [Accepted: 11/21/2017] [Indexed: 12/17/2022] Open
Abstract
Human T cell leukemia virus (HTLV)-1 Tax (Tax) protein is very important in viral replication and cell transformation. Tax localizes in the nucleus and cytoplasm in association with organelles. Some activities of Tax depend on interactions with PDZ (PSD-95/Discs Large/Z0-1) domain-containing proteins such as Discs large protein 1 (DLG1) which is involved in cell polarity and proliferation. The DLG1 interaction results in a cytoplasmic co-localization pattern resembling vesicular aggregates, the nature of which is still unknown. To further explore the role of PDZ proteins in HTLV-1 cell transformation, we deeply investigated the Tax-DLG1 association. By fluorescence resonance energy transfer (FRET), we detected, for the first time, the direct binding of Tax to DLG1 within the cell. We showed that the interaction specifically affects the cellular distribution of not only DLG1, but also Tax. After studying different cell structures, we demonstrated that the aggregates distribute into the Golgi apparatus in spatial association with the microtubule-organizing center (MTOC). This study contributes to understand the biological significance of Tax-PDZ interactions.
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Affiliation(s)
- Federico Marziali
- Instituto de Biología Molecular y Celular de Rosario-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
| | - Marina Bugnon Valdano
- Instituto de Biología Molecular y Celular de Rosario-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
| | - Clarisse Brunet Avalos
- Instituto de Biología Molecular y Celular de Rosario-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
| | - Lucía Moriena
- Instituto de Biología Molecular y Celular de Rosario-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
| | - Ana Laura Cavatorta
- Instituto de Biología Molecular y Celular de Rosario-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
| | - Daniela Gardiol
- Instituto de Biología Molecular y Celular de Rosario-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
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Nuclear Import of Hepatitis B Virus Capsids and Genome. Viruses 2017; 9:v9010021. [PMID: 28117723 PMCID: PMC5294990 DOI: 10.3390/v9010021] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/17/2017] [Accepted: 01/17/2017] [Indexed: 02/07/2023] Open
Abstract
Hepatitis B virus (HBV) is an enveloped pararetrovirus with a DNA genome, which is found in an up to 36 nm-measuring capsid. Replication of the genome occurs via an RNA intermediate, which is synthesized in the nucleus. The virus must have thus ways of transporting its DNA genome into this compartment. This review summarizes the data on hepatitis B virus genome transport and correlates the finding to those from other viruses.
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10
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Cautain B, Hill R, de Pedro N, Link W. Components and regulation of nuclear transport processes. FEBS J 2014; 282:445-62. [PMID: 25429850 PMCID: PMC7163960 DOI: 10.1111/febs.13163] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/11/2014] [Accepted: 11/12/2014] [Indexed: 12/27/2022]
Abstract
The spatial separation of DNA replication and gene transcription in the nucleus and protein translation in the cytoplasm is a uniform principle of eukaryotic cells. This compartmentalization imposes a requirement for a transport network of macromolecules to shuttle these components in and out of the nucleus. This nucleo‐cytoplasmic transport of macromolecules is critical for both cell physiology and pathology. Consequently, investigating its regulation and disease‐associated alterations can reveal novel therapeutic approaches to fight human diseases, such as cancer or viral infection. The characterization of the nuclear pore complex, the identification of transport signals and transport receptors, as well as the characterization of the Ran system (providing the energy source for efficient cargo transport) has greatly facilitated our understanding of the components, mechanisms and regulation of the nucleo‐cytoplasmic transport of proteins in our cells. Here we review this knowledge with a specific emphasis on the selection of disease‐relevant molecular targets for potential therapeutic intervention.
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Affiliation(s)
- Bastien Cautain
- Fundacion MEDINA Parque tecnológico ciencias de la salud, Granada, Spain
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11
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Medina F, Quintremil S, Alberti C, Barriga A, Cartier L, Puente J, Ramírez E, Ferreira A, Tanaka Y, Valenzuela MA. Tax posttranslational modifications and interaction with calreticulin in MT-2 cells and human peripheral blood mononuclear cells of human T cell lymphotropic virus type-I-associated myelopathy/tropical spastic paraparesis patients. AIDS Res Hum Retroviruses 2014; 30:370-9. [PMID: 24321043 DOI: 10.1089/aid.2013.0036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The human retrovirus human T cell lymphotropic virus type-I (HTLV-1) is the etiologic agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Axonal degeneration in HAM/TSP patients occurs without neuron infection, with the secreted viral Tax protein proposed to be involved. We previously found that Tax secreted into the culture medium of MT-2 cells (HTLV-1-infected cell line) produced neurite retraction in neuroblastoma cells differentiated to neuronal type. To assess the relevance of Tax posttranslational modifications on this effect, we addressed the question of whether Tax secreted by MT-2 cells and peripheral blood mononuclear cells (PBMCs) of HTLV-1-infected subjects is modified. The interaction of Tax with calreticulin (CRT) that modulates intracellular Tax localization and secretion has been described. We studied Tax localization and modifications in MT-2 cells and its interaction with CRT. Intracellular Tax in MT-2 cells was assessed by flow cytometry, corresponding mainly to a 71-kDa protein followed by western blot. This protein reported as a chimera with gp21 viral protein-confirmed by mass spectrometry-showed no ubiquitination or SUMOylation. The Tax-CRT interaction was determined by confocal microscopy and coimmunoprecipitation. Extracellular Tax from HAM/TSP PBMCs is ubiquitinated according to western blot, and its interaction with CRT was shown by coimmunoprecipitation. A positive correlation between Tax and CRT secretion was observed in HAM/TSP PBMCs and asymptomatic carriers. For both proteins inhibitors and activators of secretion showed secretion through the endoplasmic reticulum-Golgi complex. Tax, present in PBMC culture medium, produced neurite retraction in differentiated neuroblastoma cells. These results suggest that Tax, whether ubiquitinated or not, is active for neurite retraction.
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Affiliation(s)
- Fernando Medina
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Sebastian Quintremil
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Carolina Alberti
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Andres Barriga
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Luis Cartier
- Departamento de Ciencias Neurológicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Javier Puente
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Eugenio Ramírez
- Programa de Virología, Facultad de Medicina, Universidad de Chile, and Departamento de Virología, ISP, Santiago, Chile
| | - Arturo Ferreira
- Programa de Inmunologia, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Yuetsu Tanaka
- Department of Immunology, Graduate School and Faculty of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Maria Antonieta Valenzuela
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
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Currer R, Van Duyne R, Jaworski E, Guendel I, Sampey G, Das R, Narayanan A, Kashanchi F. HTLV tax: a fascinating multifunctional co-regulator of viral and cellular pathways. Front Microbiol 2012; 3:406. [PMID: 23226145 PMCID: PMC3510432 DOI: 10.3389/fmicb.2012.00406] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 11/12/2012] [Indexed: 12/18/2022] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) has been identified as the causative agent of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The virus infects between 15 and 20 million people worldwide of which approximately 2-5% develop ATL. The past 35 years of research have yielded significant insight into the pathogenesis of HTLV-1, including the molecular characterization of Tax, the viral transactivator, and oncoprotein. In spite of these efforts, the mechanisms of oncogenesis of this pleiotropic protein remain to be fully elucidated. In this review, we illustrate the multiple oncogenic roles of Tax by summarizing a recent body of literature that refines our understanding of cellular transformation. A focused range of topics are discussed in this review including Tax-mediated regulation of the viral promoter and other cellular pathways, particularly the connection of the NF-κB pathway to both post-translational modifications (PTMs) of Tax and subcellular localization. Specifically, recent research on polyubiquitination of Tax as it relates to the activation of the IkappaB kinase (IKK) complex is highlighted. Regulation of the cell cycle and DNA damage responses due to Tax are also discussed, including Tax interaction with minichromosome maintenance proteins and the role of Tax in chromatin remodeling. The recent identification of HTLV-3 has amplified the importance of the characterization of emerging viral pathogens. The challenge of the molecular determination of pathogenicity and malignant disease of this virus lies in the comparison of the viral transactivators of HTLV-1, -2, and -3 in terms of transformation and immortalization. Consequently, differences between the three proteins are currently being studied to determine what factors are required for the differences in tumorogenesis.
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Affiliation(s)
- Robert Currer
- National Center for Biodefense and Infectious Diseases, George Mason University Manassas, VA, USA
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13
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Khadka S, Vangeloff AD, Zhang C, Siddavatam P, Heaton NS, Wang L, Sengupta R, Sahasrabudhe S, Randall G, Gribskov M, Kuhn RJ, Perera R, LaCount DJ. A physical interaction network of dengue virus and human proteins. Mol Cell Proteomics 2011; 10:M111.012187. [PMID: 21911577 DOI: 10.1074/mcp.m111.012187] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Dengue virus (DENV), an emerging mosquito-transmitted pathogen capable of causing severe disease in humans, interacts with host cell factors to create a more favorable environment for replication. However, few interactions between DENV and human proteins have been reported to date. To identify DENV-human protein interactions, we used high-throughput yeast two-hybrid assays to screen the 10 DENV proteins against a human liver activation domain library. From 45 DNA-binding domain clones containing either full-length viral genes or partially overlapping gene fragments, we identified 139 interactions between DENV and human proteins, the vast majority of which are novel. These interactions involved 105 human proteins, including six previously implicated in DENV infection and 45 linked to the replication of other viruses. Human proteins with functions related to the complement and coagulation cascade, the centrosome, and the cytoskeleton were enriched among the DENV interaction partners. To determine if the cellular proteins were required for DENV infection, we used small interfering RNAs to inhibit their expression. Six of 12 proteins targeted (CALR, DDX3X, ERC1, GOLGA2, TRIP11, and UBE2I) caused a significant decrease in the replication of a DENV replicon. We further showed that calreticulin colocalized with viral dsRNA and with the viral NS3 and NS5 proteins in DENV-infected cells, consistent with a direct role for calreticulin in DENV replication. Human proteins that interacted with DENV had significantly higher average degree and betweenness than expected by chance, which provides additional support for the hypothesis that viruses preferentially target cellular proteins that occupy central position in the human protein interaction network. This study provides a valuable starting point for additional investigations into the roles of human proteins in DENV infection.
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Affiliation(s)
- Sudip Khadka
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
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14
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Maldonado H, Ramírez E, Utreras E, Pando ME, Kettlun AM, Chiong M, Kulkarni AB, Collados L, Puente J, Cartier L, Valenzuela MA. Inhibition of cyclin-dependent kinase 5 but not of glycogen synthase kinase 3-β prevents neurite retraction and tau hyperphosphorylation caused by secretable products of human T-cell leukemia virus type I-infected lymphocytes. J Neurosci Res 2011; 89:1489-98. [PMID: 21671254 PMCID: PMC3381896 DOI: 10.1002/jnr.22678] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 03/30/2011] [Accepted: 03/31/2011] [Indexed: 12/16/2022]
Abstract
Human T-cell leukemia virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease characterized by selective loss of axons and myelin in the corticospinal tracts. This central axonopathy may originate from the impairment of anterograde axoplasmic transport. Previous work showed tau hyperphosphorylation at T(181) in cerebrospinal fluid of HAM/TSP patients. Similar hyperphosphorylation occurs in SH-SY5Y cells incubated with supernatant from MT-2 cells (HTLV-I-infected lymphocytes secreting viral proteins, including Tax) that produce neurite shortening. Tau phosphorylation at T(181) is attributable to glycogen synthase kinase 3-β (GSK3-β) and cyclin-dependent kinase 5 (CDK5) activation. Here we investigate whether neurite retraction in the SH-SY5Y model associates with concurrent changes in other tau hyperphosphorylable residues. Threonine 181 turned out to be the only tau hyperphosphorylated residue. We also evaluate the role of GSK3-β and CDK5 in this process by using specific kinase inhibitors (LiCl, TDZD-8, and roscovitine). Changes in both GSK3-β active and inactive forms were followed by measuring the regulatory phosphorylable sites (S(9) and Y(216) , inactivating and activating phosphorylation, respectively) together with changes in β-catenin protein levels. Our results showed that LiCl and TDZD-8 were unable to prevent MT-2 supernatant-mediated neurite retraction and also that neither Y(216) nor S(9) phosphorylations were changed in GSK3-β. Thus, GSK3-β seems not to play a role in T(181) hyperphosphorylation. On the other hand, the CDK5 involvement in tau phosphorylation was confirmed by both the increase in its enzymatic activity and the absence of MT-2 neurite retraction in the presence of roscovitine or CDK5 siRNA transfection.
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Affiliation(s)
- Horacio Maldonado
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Eugenio Ramírez
- Programa de Virología, Departamento de Virología, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Elias Utreras
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, NIDCR, NIH, Bethesda, Maryland
| | - María E. Pando
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Ana M. Kettlun
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Mario Chiong
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Ashok B. Kulkarni
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, NIDCR, NIH, Bethesda, Maryland
| | - Lucía Collados
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Javier Puente
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Luis Cartier
- Departamento de Ciencias Neurológicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - María A. Valenzuela
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
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Lodewick J, Lamsoul I, Bex F. Move or die: the fate of the Tax oncoprotein of HTLV-1. Viruses 2011; 3:829-57. [PMID: 21994756 PMCID: PMC3185767 DOI: 10.3390/v3060829] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 12/12/2022] Open
Abstract
The HTLV-1 Tax protein both activates viral replication and is involved in HTLV-1-mediated transformation of T lymphocytes. The transforming properties of Tax include altering the expression of select cellular genes via activation of cellular pathways and perturbation of both cell cycle control mechanisms and apoptotic signals. The recent discovery that Tax undergoes a hierarchical sequence of posttranslational modifications that control its intracellular localization provides provocative insights into the mechanisms regulating Tax transcriptional and transforming activities.
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Affiliation(s)
- Julie Lodewick
- Institut de Recherches Microbiologiques J-M Wiame, Université Libre de Bruxelles, B-1070 Bruxelles, Belgium.
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Association of HTLV Tax proteins with TAK1-binding protein 2 and RelA in calreticulin-containing cytoplasmic structures participates in Tax-mediated NF-κB activation. Virology 2010; 408:39-48. [PMID: 20875659 DOI: 10.1016/j.virol.2010.08.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 06/22/2010] [Accepted: 08/21/2010] [Indexed: 12/20/2022]
Abstract
HTLV-1 is more pathogenic than HTLV-2 despite having a similar genome and closely related transactivating oncoproteins. Both Tax-1 protein from HTLV-1 and Tax-2 from HTLV-2 activate the NF-κB pathway. The mechanisms involved in Tax-1 deregulation of this signalling pathway have been thoroughly investigated, but little is known about regulation by Tax-2. We have compared the interaction of Tax-1 and Tax-2 with two key NF-κB signalling factors: TAK1-binding protein 2 (TAB2), an adaptor involved in the activation of TAK1 kinase, and RelA, the active subunit of the canonical RelA/p50 NF-κB transcription factor. Tax-2 formed stable complexes with both RelA and TAB2. These two NF-κB factors colocalized with Tax proteins in dotted cytoplasmic structures targeted by calreticulin, a multi-process calcium-buffering chaperone. Co-expression of RelA and/or TAB2 markedly increased Tax-mediated NF-κB activation. These findings provide new insights into the role of RelA, TAB2 and Tax in the deregulation of the NF-κB pathway.
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Galluzzi L, Kepp O, Morselli E, Vitale I, Senovilla L, Pinti M, Zitvogel L, Kroemer G. Viral strategies for the evasion of immunogenic cell death. J Intern Med 2010; 267:526-42. [PMID: 20433579 DOI: 10.1111/j.1365-2796.2010.02223.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Viral strategies for the evasion of immunogenic cell death (Symposium). J Intern Med 2010; 267: 526-542. Driven by co-evolutionary forces, viruses have refined a wide arsenal of strategies to interfere with the host defences. On one hand, viruses can block/retard programmed cell death in infected cells, thereby suppressing one of the most ancient mechanisms against viral dissemination. On the other hand, multiple viral factors can efficiently trigger the death of infected cells and uninfected cells from the immune system, which favours viral spreading and prevents/limits an active antiviral response, respectively. Moreover, several viruses are able to inhibit the molecular machinery that drives the translocation of calreticulin to the surface of dying cells. Thereby, viruses block the exposure of an engulfment signal that is required for the efficient uptake of dying cells by dendritic cells and for the induction of the immune response. In this review, we discuss a variety of mechanisms by which viruses interfere with the cell death machinery and, in particular, by which they subvert immunogenic cell death.
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19
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Zhou Y, Frey TK, Yang JJ. Viral calciomics: interplays between Ca2+ and virus. Cell Calcium 2009; 46:1-17. [PMID: 19535138 PMCID: PMC3449087 DOI: 10.1016/j.ceca.2009.05.005] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 12/23/2022]
Abstract
Ca2+ is one of the most universal and versatile signaling molecules and is involved in almost every aspect of cellular processes. Viruses are adept at utilizing the universal Ca2+ signal to create a tailored cellular environment that meets their own demands. This review summarizes most of the known mechanisms by which viruses perturb Ca2+ homeostasis and utilize Ca2+ and cellular Ca2+-binding proteins to their benefit in their replication cycles. Ca2+ plays important roles in virion structure formation, virus entry, viral gene expression, posttranslational processing of viral proteins and virion maturation and release. As part of the review, we introduce an algorithm to identify linear “EF-hand” Ca2+-binding motifs which resulted in the prediction of a total of 93 previously unrecognized Ca2+-binding motifs in virus proteins. Many of these proteins are nonstructural proteins, a class of proteins among which Ca2+ interactions had not been formerly appreciated. The presence of linear Ca2+-binding motifs in viral proteins enlarges the spectrum of Ca2+–virus interplay and expands the total scenario of viral calciomics.
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Affiliation(s)
- Yubin Zhou
- Department of Chemistry, Georgia State University, 50 Decatur St., Atlanta, GA 30303 USA
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20
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Boxus M, Twizere JC, Legros S, Dewulf JF, Kettmann R, Willems L. The HTLV-1 Tax interactome. Retrovirology 2008; 5:76. [PMID: 18702816 PMCID: PMC2533353 DOI: 10.1186/1742-4690-5-76] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 08/14/2008] [Indexed: 12/22/2022] Open
Abstract
The Tax1 oncoprotein encoded by Human T-lymphotropic virus type I is a major determinant of viral persistence and pathogenesis. Tax1 affects a wide variety of cellular signalling pathways leading to transcriptional activation, proliferation and ultimately transformation. To carry out these functions, Tax1 interacts with and modulates activity of a number of cellular proteins. In this review, we summarize the present knowledge of the Tax1 interactome and propose a rationale for the broad range of cellular proteins identified so far.
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Affiliation(s)
- Mathieu Boxus
- University Academia Wallonie-Europe, Molecular and Cellular Biology at FUSAGx, Gembloux, Belgium.
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21
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Nørgaard Toft K, Larsen N, Steen Jørgensen F, Højrup P, Houen G, Vestergaard B. Small angle X-ray scattering study of calreticulin reveals conformational plasticity. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1265-70. [PMID: 18559259 DOI: 10.1016/j.bbapap.2008.05.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 04/17/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
Abstract
Calreticulin plays a central role in vital cell processes such as protein folding, Ca(2+) homeostasis and immunogenicity. Even so, only limited three-dimensional structural information is presently available. We present a series of Small-Angle X-ray Scattering data on human placenta calreticulin. The data from the calreticulin monomer reveal the shape of calreticulin in solution: The previously structurally un-described C-terminal is seen as a globular domain, and the P-domain beta-hairpin extends from the N-domain in a spiral like conformation. In the calreticulin solution dimer, the N-, C-, and P-domains are easily identified, and the P-domain is in an extended conformation connecting to the second calreticulin molecule. The SAXS solution data enables the construction of a medium-resolution model of calreticulin. In the light of the unresolved chaperone mechanism of calreticulin and calnexin, we discuss the functional consequences of the conformational plasticity of the calreticulin P-domain.
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Affiliation(s)
- Katrine Nørgaard Toft
- Department of Medicinal Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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22
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Gatza ML, Dayaram T, Marriott SJ. Ubiquitination of HTLV-I Tax in response to DNA damage regulates nuclear complex formation and nuclear export. Retrovirology 2007; 4:95. [PMID: 18081936 PMCID: PMC2234431 DOI: 10.1186/1742-4690-4-95] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 12/14/2007] [Indexed: 01/28/2023] Open
Abstract
Background The HTLV-I oncoprotein, Tax, is a pleiotropic protein whose activity is partially regulated by its ability to interact with, and perturb the functions of, numerous cellular proteins. Tax is predominantly a nuclear protein that localizes to nuclear foci known as Tax Speckled Structures (TSS). We recently reported that the localization of Tax and its interactions with cellular proteins are altered in response to various forms of genotoxic and cellular stress. The level of cytoplasmic Tax increases in response to stress and this relocalization depends upon the interaction of Tax with CRM1. Cellular pathways and signals that regulate the subcellular localization of Tax remain to be determined. However, post-translational modifications including sumoylation and ubiquitination are known to influence the subcellular localization of Tax and its interactions with cellular proteins. The sumoylated form of Tax exists predominantly in the nucleus while ubiquitinated Tax exists predominantly in the cytoplasm. Therefore, we hypothesized that post-translational modifications of Tax that occur in response to DNA damage regulate the localization of Tax and its interactions with cellular proteins. Results We found a significant increase in mono-ubiquitination of Tax in response to UV irradiation. Mutation of specific lysine residues (K280 and K284) within Tax inhibited DNA damage-induced ubiquitination. In contrast to wild-type Tax, which undergoes transient nucleocytoplasmic shuttling in response to DNA damage, the K280 and K284 mutants were retained in nuclear foci following UV irradiation and remained co-localized with the cellular TSS protein, sc35. Conclusion This study demonstrates that the localization of Tax, and its interactions with cellular proteins, are dynamic following DNA damage and depend on the post-translational modification status of Tax. Specifically, DNA damage induces the ubiquitination of Tax at K280 and K284. Ubiquitination of these residues facilitates the dissociation of Tax from sc35-containing nuclear foci, and stimulates nuclear export of Tax through the CRM1 pathway.
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Affiliation(s)
- Michael L Gatza
- Department of Molecular Virology and Microbiology, Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
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Jain P, Mostoller K, Flaig KE, Ahuja J, Lepoutre V, Alefantis T, Khan ZK, Wigdahl B. Identification of Human T Cell Leukemia Virus Type 1 Tax Amino Acid Signals and Cellular Factors Involved in Secretion of the Viral Oncoprotein. J Biol Chem 2007; 282:34581-93. [PMID: 17897946 DOI: 10.1074/jbc.m707317200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Human T cell leukemia virus type 1 (HTLV-1) is the etiologic agent of a number of pathologic abnormalities, including adult T cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The viral oncoprotein Tax has been implicated in the pathogenesis of these diseases. Recently, cell-free Tax was detected in the cerebrospinal fluid of HAM/TSP patients, implying that extracellular Tax may be relevant to neurologic disease. Additionally, the presence of a nuclear export signal within Tax and its active secretion has been demonstrated in vitro. However, the mechanism of Tax secretion remains to be established. Studies reported herein elucidate the process of Tax secretion and identify domains of Tax critical to its subcellular localization and secretion. Tax was shown to interact with a number of cellular secretory pathway proteins in both the model cell line BHK (baby hamster kidney)-21 and an HTLV-1-infected T cell line, C8166, physiologically relevant to HTLV-1-induced disease. Silencing of selected components of the secretory pathway affected Tax secretion, further confirming regulated secretion of Tax. Additionally, mutations in two putative secretory signals within Tax DHE and YTNI resulted in aberrant subcellular localization of Tax and significantly altered protein secretion. Together, these studies demonstrate that Tax secretion is a regulated event facilitated by its interactions with proteins of the cellular secretory pathway and the presence of secretory signals within the carboxyl-terminal domain of the protein.
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MESH Headings
- Animals
- Cricetinae
- Gene Products, tax/cerebrospinal fluid
- Gene Products, tax/genetics
- Gene Products, tax/metabolism
- Gene Silencing
- Human T-lymphotropic virus 1/genetics
- Human T-lymphotropic virus 1/metabolism
- Human T-lymphotropic virus 1/pathogenicity
- Humans
- Jurkat Cells
- Leukemia-Lymphoma, Adult T-Cell/cerebrospinal fluid
- Leukemia-Lymphoma, Adult T-Cell/genetics
- Leukemia-Lymphoma, Adult T-Cell/virology
- Nuclear Export Signals/physiology
- Paraparesis, Tropical Spastic/cerebrospinal fluid
- Paraparesis, Tropical Spastic/genetics
- Paraparesis, Tropical Spastic/virology
- Protein Structure, Tertiary/physiology
- Protein Transport/physiology
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Affiliation(s)
- Pooja Jain
- Department of Microbiology and Immunology, Center for Molecular Virology and Neuroimmunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
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Pandya D, Rahman S, Wigdahl B, Khan ZK, Jain P. New insights into the pathogenesis, diagnosis and treatment of human T-cell leukemia virus type 1-induced disease. Future Virol 2007. [DOI: 10.2217/17460794.2.5.481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It has been over 25 years since the discovery of human T-cell leukemia virus type 1 (HTLV-1); however, the exact sequence of events that occur during primary infection, clinical latency or the development of disease remains unresolved. The advances in molecular virology and neuroimmunology have contributed significantly to our understanding of HTLV-1 pathogenesis, but also uncovered the complexity of the virus–host interaction both in the peripheral blood and the CNS. Here, we overview the general pathologic features of HTLV-1, molecular mechanisms of oncogenic transformation and characteristics of the host immune response during the associated neuroinflammatory process. We also discuss both current and new approaches in the diagnosis and therapy of HTLV-1 associated diseases – adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. Finally, potentially important emerging areas of research that may have an impact on our understanding of the pathogenic mechanism have been briefly introduced.
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Affiliation(s)
- Devanshi Pandya
- Drexel University College of Medicine, Department of Microbiology & Immunology, and, Center for Cancer Biology, Institute for Molecular Medicine & Infectious Disease, Philadelphia, PA 19102, USA
| | - Saifur Rahman
- Drexel University College of Medicine, Department of Microbiology & Immunology, and, Center for Cancer Biology, Institute for Molecular Medicine & Infectious Disease, Philadelphia, PA 19102, USA
| | - Brian Wigdahl
- Drexel University College of Medicine, Department of Microbiology & Immunology, and, Center for Cancer Biology, Institute for Molecular Medicine & Infectious Disease, Philadelphia, PA 19102, USA
| | - Zafar K Khan
- Drexel University College of Medicine, Department of Microbiology & Immunology, and, Center for Cancer Biology, Institute for Molecular Medicine & Infectious Disease, Philadelphia, PA 19102, USA
| | - Pooja Jain
- Drexel University College of Medicine, Department of Microbiology & Immunology, Institute for Molecular Medicine & Infectious Disease, New College Building, Room 18311, 245 North 15th Street, Philadelphia, PA 19102, USA
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