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Liu Y, Zhou H, Tang X. STUB1/CHIP: New insights in cancer and immunity. Biomed Pharmacother 2023; 165:115190. [PMID: 37506582 DOI: 10.1016/j.biopha.2023.115190] [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: 06/04/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The STUB1 gene (STIP1 homology and U-box-containing protein 1), located at 16q13.3, encodes the CHIP (carboxyl terminus of Hsc70-interacting protein), an essential E3 ligase involved in protein quality control. CHIP comprises three domains: an N-terminal tetratricopeptide repeat (TPR) domain, a middle coiled-coil domain, and a C-terminal U-box domain. It functions as a co-chaperone for heat shock protein (HSP) via the TPR domain and as an E3 ligase, ubiquitinating substrates through its U-box domain. Numerous studies suggest that STUB1 plays a crucial role in various physiological process, such as aging, autophagy, and bone remodeling. Moreover, emerging evidence has shown that STUB1 can degrade oncoproteins to exert tumor-suppressive functions, and it has recently emerged as a novel player in tumor immunity. This review provides a comprehensive overview of STUB1's role in cancer, including its clinical significance, impact on tumor progression, dual roles, tumor stem cell-like properties, angiogenesis, drug resistance, and DNA repair. In addition, we explore STUB1's functions in immune cell differentiation and maturation, inflammation, autoimmunity, antiviral immune response, and tumor immunity. Collectively, STUB1 represents a promising and valuable therapeutic target in cancer and immunology.
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Affiliation(s)
- Yongshuo Liu
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.
| | - Honghong Zhou
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaolong Tang
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.
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2
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Liang T, Li G, Lu Y, Hu M, Ma X. The Involvement of Ubiquitination and SUMOylation in Retroviruses Infection and Latency. Viruses 2023; 15:v15040985. [PMID: 37112965 PMCID: PMC10144533 DOI: 10.3390/v15040985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/15/2023] [Accepted: 04/16/2023] [Indexed: 04/29/2023] Open
Abstract
Retroviruses, especially the pathogenic human immunodeficiency virus type 1 (HIV-1), have severely threatened human health for decades. Retroviruses can form stable latent reservoirs via retroviral DNA integration into the host genome, and then be temporarily transcriptional silencing in infected cells, which makes retroviral infection incurable. Although many cellular restriction factors interfere with various steps of the life cycle of retroviruses and the formation of viral latency, viruses can utilize viral proteins or hijack cellular factors to evade intracellular immunity. Many post-translational modifications play key roles in the cross-talking between the cellular and viral proteins, which has greatly determined the fate of retroviral infection. Here, we reviewed recent advances in the regulation of ubiquitination and SUMOylation in the infection and latency of retroviruses, focusing on both host defense- and virus counterattack-related ubiquitination and SUMOylation system. We also summarized the development of ubiquitination- and SUMOylation-targeted anti-retroviral drugs and discussed their therapeutic potential. Manipulating ubiquitination or SUMOylation pathways by targeted drugs could be a promising strategy to achieve a "sterilizing cure" or "functional cure" of retroviral infection.
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Affiliation(s)
- Taizhen Liang
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou 511400, China
- Guangzhou Laboratory, Guangzhou International Bio-Island, Guangzhou 510005, China
| | - Guojie Li
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou 511400, China
- Guangzhou Laboratory, Guangzhou International Bio-Island, Guangzhou 510005, China
| | - Yunfei Lu
- Guangzhou Laboratory, Guangzhou International Bio-Island, Guangzhou 510005, China
| | - Meilin Hu
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou 511400, China
- Guangzhou Laboratory, Guangzhou International Bio-Island, Guangzhou 510005, China
| | - Xiancai Ma
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou 511400, China
- Guangzhou Laboratory, Guangzhou International Bio-Island, Guangzhou 510005, China
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
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Long Noncoding RNA: A Novel Insight into the Pathogenesis of Acute Lung Injury. J Clin Med 2023; 12:jcm12020604. [PMID: 36675533 PMCID: PMC9861694 DOI: 10.3390/jcm12020604] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/03/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), represent an acute stage of lung inflammation where the alveolar epithelium loses its functionality. ALI has a devastating impact on the population as it not only has a high rate of incidence, but also has high rates of morbidity and mortality. Due to the involvement of multiple factors, the pathogenesis of ALI is complex and is not fully understood yet. Long noncoding RNAs (lncRNAs) are a group of non-protein-coding transcripts longer than 200 nucleotides. Growing evidence has shown that lncRNAs have a decisive role in the pathogenesis of ALI. LncRNAs can either promote or hinder the development of ALI in various cell types in the lungs. Mechanistically, current studies have found that lncRNAs play crucial roles in the pathogenesis of ALI via the regulation of small RNAs (e.g., microRNAs) or downstream proteins. Undoubtedly, lncRNAs not only have the potential to reveal the underlying mechanisms of ALI pathogenesis but also serve as diagnostic and therapeutic targets for the therapy of ALI.
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Li C, Mori LP, Lyu S, Bronson R, Getzler AJ, Pipkin ME, Valente ST. The chaperone protein p32 stabilizes HIV-1 Tat and strengthens the p-TEFb/RNAPII/TAR complex promoting HIV transcription elongation. Proc Natl Acad Sci U S A 2023; 120:e2217476120. [PMID: 36584296 PMCID: PMC9910500 DOI: 10.1073/pnas.2217476120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/29/2022] [Indexed: 12/31/2022] Open
Abstract
HIV gene expression is modulated by the combinatorial activity of the HIV transcriptional activator, Tat, host transcription factors, and chromatin remodeling complexes. To identify host factors regulating HIV transcription, we used specific single-guide RNAs and endonuclease-deficient Cas9 to perform chromatin affinity purification of the integrated HIV promoter followed by mass spectrometry. The scaffold protein, p32, also called ASF/SF2 splicing factor-associated protein, was identified among the top enriched factors present in actively transcribing HIV promoters but absent in silenced ones. Chromatin immunoprecipitation analysis confirmed the presence of p32 on active HIV promoters and its enhanced recruitment by Tat. HIV uses Tat to efficiently recruit positive transcription elongation factor b (p-TEFb) (CDK9/CCNT1) to TAR, an RNA secondary structure that forms from the first 59 bp of HIV transcripts, to enhance RNAPII transcriptional elongation. The RNA interference of p32 significantly reduced HIV transcription in primary CD4+T cells and in HIV chronically infected cells, independently of either HIV splicing or p32 anti-splicing activity. Conversely, overexpression of p32 specifically increased Tat-dependent HIV transcription. p32 was found to directly interact with Tat's basic domain enhancing Tat stability and half-life. Conversely, p32 associates with Tat via N- and C-terminal domains. Likely due its scaffold properties, p32 also promoted Tat association with TAR, p-TEFb, and RNAPII enhancing Tat-dependent HIV transcription. In sum, we identified p32 as a host factor that interacts with and stabilizes Tat protein, promotes Tat-dependent transcriptional regulation, and may be explored for HIV-targeted transcriptional inhibition.
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Affiliation(s)
- Chuan Li
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
| | - Luisa P. Mori
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
| | - Shuang Lyu
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
| | - Ronald Bronson
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
| | - Adam J. Getzler
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
| | - Matthew E. Pipkin
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
| | - Susana T. Valente
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
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Xu M, Zhang J. A siRNA screening of UBE2 family demonstrated that UBE2R1 had a high repressive effect on HIV Tat protein. Biochem Biophys Rep 2022; 32:101366. [PMID: 36275929 PMCID: PMC9578976 DOI: 10.1016/j.bbrep.2022.101366] [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: 06/07/2022] [Revised: 09/28/2022] [Accepted: 10/05/2022] [Indexed: 10/28/2022] Open
Abstract
HIV Tat is an essential protein required for the transcription elongation of HIV genome. It has been shown that Tat can be degraded by either proteasome or autophagy pathways. In this study, it was shown that proteasome inhibitor MG132 could significantly prevent HIV Tat protein degradation in Tat over-expressing HeLa cells but it had a moderate effect in preventing Tat protein degradation in Jurkat T cells. A screening of the available UBE2 siRNA family identified that UBE2R1 had a high repressive effect on Tat protein but not on Tat mRNA level. This study further showed that RNF20 might not be the E3 ligase of Tat but was required to maintain a high level of H2B-monoubiquitylation (H2Bub1) on HIV-1 genome for efficient elongation. Overall, our study indicated that UBE2R1 might be the potential ubiquitin E2 ligase for HIV Tat protein turnover and RNF20 regulated HIV expression in the transcription elongation level.
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Affiliation(s)
- Muyu Xu
- Regulatory Biology Department, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd, California, 92037, USA,Corresponding author.
| | - Jiying Zhang
- University of Chinese Academy of Sciences, 19 Yuquan Rd, Shijingshan District, Beijing, 100049, China
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Mediouni S, Lyu S, Schader SM, Valente ST. Forging a Functional Cure for HIV: Transcription Regulators and Inhibitors. Viruses 2022; 14:1980. [PMID: 36146786 PMCID: PMC9502519 DOI: 10.3390/v14091980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/28/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
Current antiretroviral therapy (ART) increases the survival of HIV-infected individuals, yet it is not curative. The major barrier to finding a definitive cure for HIV is our inability to identify and eliminate long-lived cells containing the dormant provirus, termed viral reservoir. When ART is interrupted, the viral reservoir ensures heterogenous and stochastic HIV viral gene expression, which can reseed infection back to pre-ART levels. While strategies to permanently eradicate the virus have not yet provided significant success, recent work has focused on the management of this residual viral reservoir to effectively limit comorbidities associated with the ongoing viral transcription still observed during suppressive ART, as well as limit the need for daily ART. Our group has been at the forefront of exploring the viability of the block-and-lock remission approach, focused on the long-lasting epigenetic block of viral transcription such that without daily ART, there is no risk of viral rebound, transmission, or progression to AIDS. Numerous studies have reported inhibitors of both viral and host factors required for HIV transcriptional activation. Here, we highlight and review some of the latest HIV transcriptional inhibitor discoveries that may be leveraged for the clinical exploration of block-and-lock and revolutionize the way we treat HIV infections.
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Affiliation(s)
- Sonia Mediouni
- Department of Immunology and Microbiology, UF Scripps Biomedical Research, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA
| | - Shuang Lyu
- Department of Immunology and Microbiology, UF Scripps Biomedical Research, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA
| | - Susan M. Schader
- Department of Infectious Disease Research, Drug Development Division, Southern Research, 431 Aviation Way, Frederick, MD 21701, USA
| | - Susana T. Valente
- Department of Immunology and Microbiology, UF Scripps Biomedical Research, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA
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Ning S, Zeng C, Zeng C, Zhao Y. The TAR binding dynamics and its implication in Tat degradation mechanism. Biophys J 2021; 120:5158-5168. [PMID: 34762866 PMCID: PMC8715215 DOI: 10.1016/j.bpj.2021.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/25/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022] Open
Abstract
Human immunodeficiency virus (HIV) is a retrovirus that progressively attacks the human immune system. It is known that the HIV viral protein Tat recruits the host elongation factor, positive transcription elongation factor b (P-TEFb), onto the nascent HIV viral transactivation response element (TAR) RNA to overcome the elongation pause for active transcription of the entire viral genome. Interestingly, there exists an amplifying feedback loop between Tat and TAR-a reduction in Tat increases the elongation pause, resulting in more TAR RNA fragments instead of the entire viral genome transcript, and the TAR fragments as a scaffold for PRC2 complex in turn promote Tat ubiquitination and degradation. In this study, the structural ensembles and binding dynamics of various interfaces in the Tat/TAR/P-TEFb complex are probed by all-atom accelerated sampling molecular dynamics simulations. The results show that a protein-binding inhibitor F07#13 targeting the Tat/P-TEFb interface initiates the above feedback loop and shuts down the active transcription. Another RNA binding inhibitor, JB181, targeting the Tat/TAR interface, can prevent TAR from pulling down the Tat from P-TEFb protein and further reducing Tat degradation. The detailed mechanism of the complex dynamics helps elucidate how Tat and TAR coordinate the regulation between HIV genome transcription versus possible HIV latency.
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Affiliation(s)
- Shangbo Ning
- Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China
| | - Chengwei Zeng
- Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China
| | - Chen Zeng
- Department of Physics, The George Washington University, Washington, DC
| | - Yunjie Zhao
- Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China.
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Ali A, Kumar V, Banerjea AC. STUB1/CHIP promotes ubiquitination and degradation of HIV-1 Vif to restore the cellular level of APOBEC3G protein. Biochem Biophys Res Commun 2021; 574:27-32. [PMID: 34425283 DOI: 10.1016/j.bbrc.2021.08.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
HIV-1 accessory protein Vif is required for neutralization of cellular restriction factor APOBEC3G through its ubiquitination and proteasomal degradation which allows replication of HIV-1 in non-permissive cells. This function of Vif is required for maintaining the genomic integrity of HIV-1. We here report that the Vif interacts with the cellular E3 ubiquitin ligase CHIP and the level of Vif protein gets reduced by the expression of CHIP. Reduction of Vif by CHIP expression is due to its increased rate of degradation as shown by cycloheximide (CHX) chase assay. CHIP expression also resulted in the ubiquitination of Vif protein in a dose dependent manner. The role of CHIP in the ubiquitination and degradation was confirmed by the endogenous knockdown of CHIP using CRISPR Cas9 method. Loss of endogenous CHIP protein showed the stabilization of Vif with concomitant destabilization of APOBEC3G. As expected Vif mediated ubiquitination of APOBEC3G was also reduced in CHIP knockdown cells. These results established that CHIP functions as a negative regulator of Vif protein which in-turn stabilizes APOBEC3G.
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Affiliation(s)
- Amjad Ali
- Laboratory of Virology, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
| | - Vivek Kumar
- Laboratory of Virology, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Akhil C Banerjea
- Laboratory of Virology, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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Kumar S, Basu M, Ghosh MK. Chaperone-assisted E3 ligase CHIP: A double agent in cancer. Genes Dis 2021; 9:1521-1555. [PMID: 36157498 PMCID: PMC9485218 DOI: 10.1016/j.gendis.2021.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/06/2021] [Indexed: 12/11/2022] Open
Abstract
The carboxy-terminus of Hsp70-interacting protein (CHIP) is a ubiquitin ligase and co-chaperone belonging to Ubox family that plays a crucial role in the maintenance of cellular homeostasis by switching the equilibrium of the folding-refolding mechanism towards the proteasomal or lysosomal degradation pathway. It links molecular chaperones viz. HSC70, HSP70 and HSP90 with ubiquitin proteasome system (UPS), acting as a quality control system. CHIP contains charged domain in between N-terminal tetratricopeptide repeat (TPR) and C-terminal Ubox domain. TPR domain interacts with the aberrant client proteins via chaperones while Ubox domain facilitates the ubiquitin transfer to the client proteins for ubiquitination. Thus, CHIP is a classic molecule that executes ubiquitination for degradation of client proteins. Further, CHIP has been found to be indulged in cellular differentiation, proliferation, metastasis and tumorigenesis. Additionally, CHIP can play its dual role as a tumor suppressor as well as an oncogene in numerous malignancies, thus acting as a double agent. Here, in this review, we have reported almost all substrates of CHIP established till date and classified them according to the hallmarks of cancer. In addition, we discussed about its architectural alignment, tissue specific expression, sub-cellular localization, folding-refolding mechanisms of client proteins, E4 ligase activity, normal physiological roles, as well as involvement in various diseases and tumor biology. Further, we aim to discuss its importance in HSP90 inhibitors mediated cancer therapy. Thus, this report concludes that CHIP may be a promising and worthy drug target towards pharmaceutical industry for drug development.
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Fan W, Mar KB, Sari L, Gaszek IK, Cheng Q, Evers BM, Shelton JM, Wight-Carter M, Siegwart DJ, Lin MM, Schoggins JW. TRIM7 inhibits enterovirus replication and promotes emergence of a viral variant with increased pathogenicity. Cell 2021; 184:3410-3425.e17. [PMID: 34062120 PMCID: PMC8276836 DOI: 10.1016/j.cell.2021.04.047] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 03/23/2021] [Accepted: 04/28/2021] [Indexed: 02/07/2023]
Abstract
To control viral infection, vertebrates rely on both inducible interferon responses and less well-characterized cell-intrinsic responses composed of "at the ready" antiviral effector proteins. Here, we show that E3 ubiquitin ligase TRIM7 is a cell-intrinsic antiviral effector that restricts multiple human enteroviruses by targeting viral 2BC, a membrane remodeling protein, for ubiquitination and proteasome-dependent degradation. Selective pressure exerted by TRIM7 results in emergence of a TRIM7-resistant coxsackievirus with a single point mutation in the viral 2C ATPase/helicase. In cultured cells, the mutation helps the virus evade TRIM7 but impairs optimal viral replication, and this correlates with a hyperactive and structurally plastic 2C ATPase. Unexpectedly, the TRIM7-resistant virus has a replication advantage in mice and causes lethal pancreatitis. These findings reveal a unique mechanism for targeting enterovirus replication and provide molecular insight into the benefits and trade-offs of viral evolution imposed by a host restriction factor.
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Affiliation(s)
- Wenchun Fan
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Katrina B Mar
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Levent Sari
- Green Center for Molecular, Computational, and Systems Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ilona K Gaszek
- Green Center for Molecular, Computational, and Systems Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Qiang Cheng
- Department of Biochemistry, Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Bret M Evers
- Departments of Pathology and Ophthalmology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - John M Shelton
- Department of Internal Medicine, Histo Pathology Core Division, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mary Wight-Carter
- Animal Resource Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Daniel J Siegwart
- Department of Biochemistry, Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Milo M Lin
- Green Center for Molecular, Computational, and Systems Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - John W Schoggins
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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Castro-Gonzalez S, Simpson S, Shi Y, Chen Y, Benjamin J, Serra-Moreno R. HIV Nef-mediated Ubiquitination of BCL2: Implications in Autophagy and Apoptosis. Front Immunol 2021; 12:682624. [PMID: 34025682 PMCID: PMC8134690 DOI: 10.3389/fimmu.2021.682624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/21/2021] [Indexed: 11/13/2022] Open
Abstract
Ubiquitination is a process that acts upon every step of the HIV replication cycle. The activity, subcellular localization, and stability of HIV dependency factors as well as negative modulators can be affected by ubiquitination. These modifications consequently have an impact on the progression and outcome of infection. Additionally, recent findings suggest new roles for ubiquitination in the interplay between HIV and the cellular environment, specifically in the interactions between HIV, autophagy and apoptosis. On one hand, autophagy is a defense mechanism against HIV that promotes the degradation of the viral protein Gag, likely through ubiquitination. Gag is an essential structural protein that drives virion assembly and release. Interestingly, the ubiquitination of Gag is vital for HIV replication. Hence, this post-translational modification in Gag represents a double-edged sword: necessary for virion biogenesis, but potentially detrimental under conditions of autophagy activation. On the other hand, HIV uses Nef to circumvent autophagy-mediated restriction by promoting the ubiquitination of the autophagy inhibitor BCL2 through Parkin/PRKN. Although the Nef-promoted ubiquitination of BCL2 occurs in both the endoplasmic reticulum (ER) and mitochondria, only ER-associated ubiquitinated BCL2 arrests the progression of autophagy. Importantly, both mitochondrial BCL2 and PRKN are tightly connected to mitochondrial function and apoptosis. Hence, by enhancing the PRKN-mediated ubiquitination of BCL2 at the mitochondria, HIV might promote apoptosis. Moreover, this effect of Nef might account for HIV-associated disorders. In this article, we outline our current knowledge and provide perspectives of how ubiquitination impacts the molecular interactions between HIV, autophagy and apoptosis.
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Affiliation(s)
- Sergio Castro-Gonzalez
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Sydney Simpson
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Yuhang Shi
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Yuexuan Chen
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Jared Benjamin
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Ruth Serra-Moreno
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
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