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Kusunoki H, Sakamoto T, Kobayashi N, Kohno T, Wakamatsu K, Nagata T. Structural Insights into the Interaction between the C-Terminal-Deleted BH3-like Motif Peptide of Hepatitis B Virus X Protein and Bcl-x L. Biochemistry 2024; 63:632-643. [PMID: 38377677 DOI: 10.1021/acs.biochem.3c00709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Hepatitis B virus X protein (HBx) plays a crucial role in the development of hepatocellular carcinoma (HCC) associated with hepatitis B virus (HBV) infection. The full-length HBx protein interacts with Bcl-xL and is involved in the HBV replication and cell death processes. The three hydrophobic residues Trp120, Leu123, and Ile127 of the HBx BH3-like motif are essential for the Bcl-xL-binding. On the other hand, various lengths of C-terminal-truncated HBx mutants are frequently detected in HCC tissues, and these mutants, rather than the full-length HBx, appear to be responsible for HCC development. Notably, the region spanning residues 1-120 of HBx [HBx(1 and 120)] has been strongly associated with an increased risk of HCC development. However, the mode of interaction between HBx(1-120) and Bcl-xL remains unclear. HBx(1-120) possesses only Trp120 among the three hydrophobic residues essential for the Bcl-xL-binding. To elucidate this interaction mode, we employed a C-terminal-deleted HBx BH3-like motif peptide composed of residues 101-120. Here, we present the NMR complex structure of Bcl-xL and HBx(101-120). Our results demonstrate that HBx(101-120) binds to Bcl-xL in a weaker manner. Considering the high expression of Bcl-xL in HCC cells, this weak interaction, in conjunction with the overexpression of Bcl-xL in HCC cells, may potentially contribute to HCC development through the interaction between C-terminal-truncated HBx and Bcl-xL.
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Affiliation(s)
- Hideki Kusunoki
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Musashimurayama, Tokyo 208-0011, Japan
| | - Taiichi Sakamoto
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, Narashino, Chiba 275-0016, Japan
| | - Naohiro Kobayashi
- Laboratory for Advanced NMR Application and Development, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa 230-0045, Japan
| | - Toshiyuki Kohno
- Department of Medical Informatics, Research and Development Center for Medical Education, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Kaori Wakamatsu
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Takashi Nagata
- Institute of Advanced Energy, Kyoto University, Kyoto, Uji 611-0011, Japan
- Graduate School of Energy Science, Kyoto University, Kyoto, Uji 611-0011, Japan
- Integrated Research Center for Carbon Negative Science, Kyoto University, Kyoto, Uji 611-0011, Japan
- Biomass Product Tree Industry-Academia Collaborative Research Laboratory, Kyoto University, Kyoto, Uji 611-0011, Japan
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Morovati S, Mohammadi A, Masoudi R, Heidari AA, Asad Sangabi M. The power of mumps virus: Matrix protein activates apoptotic pathways in human colorectal cell lines. PLoS One 2023; 18:e0295819. [PMID: 38091318 PMCID: PMC10718445 DOI: 10.1371/journal.pone.0295819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
New therapeutic approaches can significantly impact the control of colorectal cancer (CRC), which is increasing worldwide. In this study, we investigated the potential of targeting viral proteins to combat cancer cells. Specifically, we examined the anticancer potential of the matrix (M) protein of the mumps virus Hoshino strain in SW480 CRC cell lines. To begin, we individually transfected SW480 cells with pcDNA3 plasmids containing the mumps virus M gene. We then investigated the percentage of cell death, caspase activity, and the expression levels of genes involved in apoptosis pathways. Following this, we performed bioinformatics analysis on the M protein to identify any similarities with Bcl-2 family members and their viral homologs. Our diagnostic methods showed that treatment with the mumps M protein induced apoptosis and upregulated the expression and activity of pro-apoptotic proteins in SW480 CRC cells compared to the control and vector groups. Based on our bioinformatics studies, we proposed that the BH3 motif in the M protein may trigger apoptosis in CRC cells by interacting with cellular Bax. Overall, our study showed for the first time that the mumps virus M protein could be considered as a targeted treatment for CRC by inducing apoptotic pathways.
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Affiliation(s)
- Solmaz Morovati
- Department of Pathobiology, Division of Biotechnology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Ali Mohammadi
- Department of Pathobiology, Division of Virology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Ramin Masoudi
- Department of Pathobiology, Division of Biotechnology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Amir Ali Heidari
- Department of Clinical Sciences, Division of Aquatic Animal Health and Diseases, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Mehdi Asad Sangabi
- Department of Pathobiology, Division of Virology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
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Canonical and Divergent N-Terminal HBx Isoform Proteins Unveiled: Characteristics and Roles during HBV Replication. Biomedicines 2021; 9:biomedicines9111701. [PMID: 34829930 PMCID: PMC8616016 DOI: 10.3390/biomedicines9111701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022] Open
Abstract
Hepatitis B virus (HBV) X protein (HBx) is a viral regulatory and multifunctional protein. It is well-known that the canonical HBx reading frame bears two phylogenetically conserved internal in-frame translational initiation codons at Met2 and Met3, thus possibly generating divergent N-terminal smaller isoforms during translation. Here, we demonstrate that the three distinct HBx isoforms are generated from the ectopically expressed HBV HBx gene, named XF (full-length), XM (medium-length), and XS (short-length); they display different subcellular localizations when expressed individually in cultured hepatoma cells. Particularly, the smallest HBx isoform, XS, displayed a predominantly cytoplasmic localization. To study HBx proteins during viral replication, we performed site-directed mutagenesis to target the individual or combinatorial expression of the HBx isoforms within the HBV viral backbone (full viral genome). Our results indicate that of all HBx isoforms, only the smallest HBx isoform, XS, can restore WT levels of HBV replication, and bind to the viral mini chromosome, thereby establishing an active chromatin state, highlighting its crucial activities during HBV replication. Intriguingly, we found that sequences of HBV HBx genotype H are devoid of the conserved Met3 position, and therefore HBV genotype H infection is naturally silent for the expression of the HBx XS isoform. Finally, we found that the HBx XM (medium-length) isoform shares significant sequence similarity with the N-terminus domain of the COMMD8 protein, a member of the copper metabolism MURR1 domain-containing (COMMD) protein family. This novel finding might facilitate studies on the phylogenetic origin of the HBV X protein. The identification and functional characterization of its isoforms will shift the paradigm by changing the concept of HBx from being a unique, canonical, and multifunctional protein toward the occurrence of different HBx isoforms, carrying out different overlapping functions at different subcellular localizations during HBV genome replication. Significantly, our current work unveils new crucial HBV targets to study for potential antiviral research, and human virus pathogenesis.
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Khan A, Ahsan O, Wei DQ, Ansari JK, Najmi MH, Muhammad K, Waheed Y. Computational Evaluation of Abrogation of HBx-Bcl-xL Complex with High-Affinity Carbon Nanotubes (Fullerene) to Halt the Hepatitis B Virus Replication. Molecules 2021; 26:6433. [PMID: 34770842 PMCID: PMC8587554 DOI: 10.3390/molecules26216433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 02/07/2023] Open
Abstract
Hepatitis B virus (HBV) is the world's most prevalent chronic viral infection. More than 350 million individuals are chronic carriers of the virus, with an estimated 2 billion infected persons. For instance, the role of HBx protein in attachment and infection is very obvious and consequently deemed as an important druggable target. Targeting the interface and discovering novel drugs greatly advanced the field of therapeutics development. Therefore, in the current study, HBx to Bcl-xL is abrogated on high-affinity carbon nanotubes using computational structural biology tools. Our analysis revealed that among the total 62 carbon fullerenes, only 13 compounds exhibited inhibitory activity against HBx, which was further confirmed through IFD-based rescoring. Structural dynamics investigation revealed stable binding, compactness, and hydrogen bonds reprogramming. Moreover, the binding free energy calculation results revealed that the top hits1-4 possess the total binding energy of -54.36 kcal/mol (hit1), -50.81 kcal/mol (hit2), -47.09 kcal/mol (hit3), and -45.59 kcal/mol for hit4. In addition, the predicted KD values and bioactivity scores further validated the inhibitory potential of these top hits. The identified compounds need further in vitro and in vivo validation to aid the treatment process of HBV.
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Affiliation(s)
- Abbas Khan
- Foundation University Medical College, Foundation University Islamabad, DHA-I, Islamabad 44000, Pakistan; (A.K.); (O.A.); (J.K.A.); (M.H.N.)
| | - Omar Ahsan
- Foundation University Medical College, Foundation University Islamabad, DHA-I, Islamabad 44000, Pakistan; (A.K.); (O.A.); (J.K.A.); (M.H.N.)
| | - Dong-Qing Wei
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China;
- State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Centre on Antibacterial Resistances, Joint Laboratory of International Laboratory of Metabolic and Developmental Sciences, Ministry of Education and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nashan District, Shenzhen 518055, China
| | - Jawad Khaliq Ansari
- Foundation University Medical College, Foundation University Islamabad, DHA-I, Islamabad 44000, Pakistan; (A.K.); (O.A.); (J.K.A.); (M.H.N.)
| | - Muzammil Hasan Najmi
- Foundation University Medical College, Foundation University Islamabad, DHA-I, Islamabad 44000, Pakistan; (A.K.); (O.A.); (J.K.A.); (M.H.N.)
| | - Khalid Muhammad
- Department of Biology, College of Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates
| | - Yasir Waheed
- Foundation University Medical College, Foundation University Islamabad, DHA-I, Islamabad 44000, Pakistan; (A.K.); (O.A.); (J.K.A.); (M.H.N.)
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HBV X protein mutations affect HBV transcription and association of histone-modifying enzymes with covalently closed circular DNA. Sci Rep 2020; 10:802. [PMID: 31964944 PMCID: PMC6972884 DOI: 10.1038/s41598-020-57637-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/24/2019] [Indexed: 12/13/2022] Open
Abstract
The hepatitis B X protein (HBx) plays a role in the epigenetic regulation of hepatitis B virus (HBV) replication. This study investigated the effects of HBx mutations on HBV transcription and the recruitment of HBx, histone acetyl-transferase P300 and histone deacetylase 1 (HDAC1) to circularized HBV DNA (which resembles covalently closed circular DNA [cccDNA]). Compared with wild type, majority of mutants had lower levels of intracellular HBV RNA (44–77% reduction) and secretory HBsAg (25–81% reduction), and 12 mutants had a reduction in intracellular encapsidated HBV DNA (33–64% reduction). Eight mutants with >70% reduction in HBV RNA and/or HBsAg were selected for chromatin immunoprecipitation analysis. Four HBx mutants with mutations in amino acid residues 55–60 and 121–126 had a lower degree of HBx-cccDNA association than wild type HBx (mean % input: 0.02–0.64% vs. 3.08% in wild type). A reduced association between cccDNA and P300 (mean % input: 0.69–1.81% vs. 3.48% in wild type) and an augmented association with HDAC1 (mean % input: 4.01–14.0% vs. 1.53% in wild type) were detected. HBx amino acid residues 55–60 and 121–126 may play an important role in HBV transcription regulation, via their impeded interaction with cccDNA and altered recruitment of histone modifying enzymes to cccDNA.
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Wang F, Shen F, Wang Y, Li Z, Chen J, Yuan Z. Residues Asn118 and Glu119 of hepatitis B virus X protein are critical for HBx-mediated inhibition of RIG-I-MAVS signaling. Virology 2020; 539:92-103. [PMID: 31706164 DOI: 10.1016/j.virol.2019.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/24/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) X protein (HBx) has been reported to counteract the innate immune responses through interfering with the pattern recognition receptors signaling activated by retinoic acid-inducible gene-I (RIG-I)-mitochondrial antiviral signaling protein (MAVS). Here, we showed that, compared to the HBx derived from genotype (gt) A, C and D, HBx of gtB exhibited more potent inhibitory activity on the RIG-I-MAVS-mediated interferon-β promoter activation. Functional analysis of the genotype-associated differences in amino acid sequence and the reciprocal mutation experiments in transient-transfection and infection cell models revealed that HBx with asparagine (N) and glutamic acid (E) at 118-119 positions inhibited RIG-I signaling and interacted with MAVS more efficiently than that with lysine (K) and aspartic acid (D). An impaired RIG-I-induced MAVS aggregation was observed in the presence of HBx-118N119E while MAVS-TRAF3 interaction was not affected. These results implicated that HBx gene heterogeneity may affect the innate immune responses to HBV infection.
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Affiliation(s)
- Fan Wang
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Fang Shen
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yang Wang
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Ze Li
- Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jieliang Chen
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| | - Zhenghong Yuan
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
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Kusunoki H, Tanaka T, Kohno T, Kimura H, Hosoda K, Wakamatsu K, Hamaguchi I. NMR characterization of the interaction between Bcl-x L and the BH3-like motif of hepatitis B virus X protein. Biochem Biophys Res Commun 2019; 518:445-450. [PMID: 31439373 DOI: 10.1016/j.bbrc.2019.08.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 08/07/2019] [Indexed: 01/10/2023]
Abstract
Hepatitis B virus X protein (HBx) possesses a BH3-like motif that directly interacts with the anti-apoptotic proteins, Bcl-2 and Bcl-xL. Here we report the interaction between the HBx BH3-like motif and Bcl-xL, as revealed by nuclear magnetic resonance spectroscopy. Our results showed that this motif binds to the common BH3-binding hydrophobic groove on the surface of Bcl-xL, with a binding affinity of 89 μM. Furthermore, we examined the role of the tryptophan residue (Trp120) in this motif in Bcl-xL binding using three mutants. The W120A mutant showed weaker binding affinity (294 μM) to Bcl-xL, whereas the W120L and W120F mutants exhibited almost equivalent binding affinity to the wild-type. These results indicate that the bulky hydrophobic residues are important for Bcl-xL binding. The findings will be helpful in understanding the apoptosis networks between viral proteins and host factors.
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Affiliation(s)
- Hideki Kusunoki
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-Murayama, Tokyo, 208-0011, Japan.
| | - Toshiyuki Tanaka
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan; Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Toshiyuki Kohno
- Department of Medical Informatics, Research and Development Center for Medical Education, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Hirokazu Kimura
- Department of Health Science, Gunma Paz University Graduate School of Health Science, 1-7-1 Tonyamachi, Takasaki, Gunma, 370-0006, Japan
| | - Kazuo Hosoda
- Department of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma, 376-8515, Japan
| | - Kaori Wakamatsu
- Department of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma, 376-8515, Japan
| | - Isao Hamaguchi
- Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-Murayama, Tokyo, 208-0011, Japan.
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Huang XY, Li D, Chen ZX, Huang YH, Gao WY, Zheng BY, Wang XZ. Hepatitis B Virus X protein elevates Parkin-mediated mitophagy through Lon Peptidase in starvation. Exp Cell Res 2018; 368:75-83. [PMID: 29689279 DOI: 10.1016/j.yexcr.2018.04.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/05/2018] [Accepted: 04/15/2018] [Indexed: 01/13/2023]
Abstract
Hepatocellular Carcinoma (HCC) is the fifth most prevalent cancer worldwide. Specially, Hepatitis B viurs X protein (HBx) is a leading factor in the progression of Hepatitis B viurs-related HCC. Nutrient-deprived tumor microenvironment also contributes to tumor development. However, the role of HBx in nutrient-deprived HCC has received little investigation. Here, we show that HBx elevates PINK1-Parkin mediating mitophagy in starvation. HBx not only increases the PINK1/Parkin gene expression but also accelerates Parkin recruitment to partial mitochondria. Further analysis indicates that, HBx either promotes mitochondrial unfolded protein response, with remarkable mitochondrial LONP1 increases, or reduces LONP1 expression in cytosol inducing LONP1-Parkin pathway, both consequently enhancing mitophagy. Moreover, the enhanced mitophagy lowers mitochondrial apoptosis in starved hepatoma cells, and Bax is implied in the machinery. In addition, we define differential centrifuge, 3000 g or 12,000 g to pellet mitochondria, as an effective method to obtain distinct mitochondria. In collect, HBx regulates diverse aspects of LONP1 and Parkin, enhancing mitophagy in starvation. This study may shed new insights into the machinery development of hepatocellular carcinoma.
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Affiliation(s)
- Xiao-Yun Huang
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
| | - Dan Li
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
| | - Zhi-Xin Chen
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
| | - Yue-Hong Huang
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
| | - Wen-Yu Gao
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
| | - Bi-Yun Zheng
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
| | - Xiao-Zhong Wang
- Department of Gastroenterology, Fujian Medical University Union Hospital, 29, Xinquan Road, Gulou, Fuzhou, Fujian 350001, PR China.
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Kusunoki H, Tanaka T, Kohno T, Kimura H, Hosoda K, Wakamatsu K, Hamaguchi I. Expression, purification and characterization of hepatitis B virus X protein BH3-like motif-linker-Bcl-x L fusion protein for structural studies. Biochem Biophys Rep 2016; 9:159-165. [PMID: 29114584 PMCID: PMC5632712 DOI: 10.1016/j.bbrep.2016.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 11/24/2022] Open
Abstract
Hepatitis B virus X protein (HBx) is a multifunctional protein that interacts directly with many host proteins. For example, HBx interacts with anti-apoptotic proteins, Bcl-2 and Bcl-xL, through its BH3-like motif, which leads to elevated cytosolic calcium levels, efficient viral DNA replication and the induction of apoptosis. To facilitate sample preparation and perform detailed structural characterization of the complex between HBx and Bcl-xL, we designed and purified a recombinant HBx BH3-like motif-linker-Bcl-xL fusion protein produced in E. coli. The fusion protein was characterized by size exclusion chromatography, circular dichroism and nuclear magnetic resonance experiments. Our results show that the fusion protein is a monomer in aqueous solution, forms a stable intramolecular complex, and likely retains the native conformation of the complex between Bcl-xL and the HBx BH3-like motif. Furthermore, the HBx BH3-like motif of the intramolecular complex forms an α-helix. These observations indicate that the fusion protein should facilitate structural studies aimed at understanding the interaction between HBx and Bcl-xL at the atomic level. Soluble HBx BH3-like motif-linker-Bcl-xL fusion protein was produced in E. coli. The fusion protein behaves as a monomer and forms a stable intramolecular complex. The HBx BH3-like motif of the fusion protein forms an α-helix. The fusion protein likely retains the native conformation of the complex.
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Affiliation(s)
- Hideki Kusunoki
- Department of Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Toshiyuki Tanaka
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Toshiyuki Kohno
- Department of Biochemistry, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan
| | - Hirokazu Kimura
- Infectious Disease Surveillance Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Kazuo Hosoda
- Department of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Kaori Wakamatsu
- Department of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Isao Hamaguchi
- Department of Research on Blood and Biological Products, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
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Cho MY, Cheong JY, Lim W, Jo S, Lee Y, Wang HJ, Han KH, Cho H. Prognostic significance of catalase expression and its regulatory effects on hepatitis B virus X protein (HBx) in HBV-related advanced hepatocellular carcinomas. Oncotarget 2015; 5:12233-46. [PMID: 25361011 PMCID: PMC4322996 DOI: 10.18632/oncotarget.2625] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/23/2014] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus X protein (HBx) plays a role in liver cancer development. We previously showed that ROS increased HBx levels and here, we investigated the role of antioxidants in the regulation of HBx expression and their clinical relevance. We found that overexpression of catalase induced a significant loss in HBx levels. The cysteine null mutant of HBx (Cys-) showed a dramatic reduction in its protein stability. In clonogenic proliferation assays, Huh7-X cells produced a significant number of colonies whereas Huh7-Cys- cells failed to generate them. The Cys at position 69 of HBx was crucial to maintain its protein stability and transactivation function in response to ROS. Among 50 HBV-related hepatocellular carcinoma (HCC) specimens, 72% of HCCs showed lower catalase levels than those of surrounding non-tumor tissues. In advanced stage IV, catalase levels in non-tumor tissues were increased whereas those in tumors were further reduced. Accordingly, patients with a high T/N ratio for catalase showed significantly longer survival than those with a low T/N ratio. Together, catalase expression in HCC patients can be clinically useful for prediction of patient survival, and restoration of catalase expression in HCCs could be an important strategy for intervention in HBV-induced liver diseases.
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Affiliation(s)
- Mi-Young Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, The Graduate School, Ajou University, Suwon, Korea. Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, Korea
| | - Jae Youn Cheong
- Department of Gastroenterology, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea
| | - Wonchung Lim
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, The Graduate School, Ajou University, Suwon, Korea. Current address: Department of Sports Medicine, Cheongju University, Cheongju, Korea
| | - Sujin Jo
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Youngsoo Lee
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Hee-Jung Wang
- Department of Surgery, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea
| | - Kyou-Hoon Han
- Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Hyeseong Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, The Graduate School, Ajou University, Suwon, Korea. Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, Korea. Genomic Instability Research Center, Ajou University School of Medicine, Suwon, Korea
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Hepatitis B virus X protein enhances Myc stability by inhibiting SCFSkp2 ubiquitin E3 ligase-mediated Myc ubiquitination and contributes to oncogenesis. Oncogene 2015; 35:1857-67. [DOI: 10.1038/onc.2015.251] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 05/05/2015] [Accepted: 05/22/2015] [Indexed: 01/19/2023]
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12
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Wei B, Cheng Y. Influence of overexpression of hepatitis B virus X gene on proliferation and migration of hepatoma cells. Shijie Huaren Xiaohua Zazhi 2014; 22:5408-5413. [DOI: 10.11569/wcjd.v22.i35.5408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the influence of overexpression of hepatitis B virus X (HBX) on the proliferation and migration of hepatoma cells.
METHODS: Human hepatic carcinoma cell line Huh7 was cultured and infected with a recombinant adenovirus vector expressing HBX to establish an Huh7-HBX cell line. Colony forming assay, MTS assay and crystal violet staining were performed to assess cell proliferation. Cell migration assay was also performed.
RESULTS: The Huh7-HBX cell line was established successfully. HBX overexpression could promote cell proliferation. The number of cell colonies formed for Huh7-HBX cells was significantly higher than that for Huh7 cells (P < 0.05). Restoration of secreted frizzled-related protein 1 (SFRP1) and SFRP5 expression or knockdown of DNA methyltransferase 1 (Dnmt1) could significantly inhibit liver cancer cell proliferation and migration (P < 0.05).
CONCLUSION: Overexpression of HBX significantly inhibits the proliferation and migration of hepatoma cells.
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