1
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Li YL, Langley CA, Azumaya CM, Echeverria I, Chesarino NM, Emerman M, Cheng Y, Gross JD. The structural basis for HIV-1 Vif antagonism of human APOBEC3G. Nature 2023; 615:728-733. [PMID: 36754086 PMCID: PMC10033410 DOI: 10.1038/s41586-023-05779-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 02/02/2023] [Indexed: 02/10/2023]
Abstract
The APOBEC3 (A3) proteins are host antiviral cellular proteins that hypermutate the viral genome of diverse viral families. In retroviruses, this process requires A3 packaging into viral particles1-4. The lentiviruses encode a protein, Vif, that antagonizes A3 family members by targeting them for degradation. Diversification of A3 allows host escape from Vif whereas adaptations in Vif enable cross-species transmission of primate lentiviruses. How this 'molecular arms race' plays out at the structural level is unknown. Here, we report the cryogenic electron microscopy structure of human APOBEC3G (A3G) bound to HIV-1 Vif, and the hijacked cellular proteins that promote ubiquitin-mediated proteolysis. A small surface explains the molecular arms race, including a cross-species transmission event that led to the birth of HIV-1. Unexpectedly, we find that RNA is a molecular glue for the Vif-A3G interaction, enabling Vif to repress A3G by ubiquitin-dependent and -independent mechanisms. Our results suggest a model in which Vif antagonizes A3G by intercepting it in its most dangerous form for the virus-when bound to RNA and on the pathway to packaging-to prevent viral restriction. By engaging essential surfaces required for restriction, Vif exploits a vulnerability in A3G, suggesting a general mechanism by which RNA binding helps to position key residues necessary for viral antagonism of a host antiviral gene.
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Affiliation(s)
- Yen-Li Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Caroline A Langley
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, USA
| | - Caleigh M Azumaya
- Fred Hutchinson Cancer Center, Electron Microscopy Shared Resource, Seattle, WA, USA
| | - Ignacia Echeverria
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA
- Quantitative Bioscience Institute, University of California, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Nicholas M Chesarino
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Michael Emerman
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Yifan Cheng
- Quantitative Bioscience Institute, University of California, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA.
- Quantitative Bioscience Institute, University of California, San Francisco, CA, USA.
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2
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Domostegui A, Nieto-Barrado L, Perez-Lopez C, Mayor-Ruiz C. Chasing molecular glue degraders: screening approaches. Chem Soc Rev 2022; 51:5498-5517. [PMID: 35723413 DOI: 10.1039/d2cs00197g] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Protein-protein interactions (PPIs) govern all biological processes. Some small molecules modulate PPIs through induced protein proximity. In particular, molecular glue degraders are monovalent compounds that orchestrate interactions between a target protein and an E3 ubiquitin ligase, prompting the proteasomal degradation of the former. This and other pharmacological strategies of targeted protein degradation (e.g. proteolysis-targeting chimeras - PROTACs) overcome some limitations of traditional occupancy-based therapeutics. Here, we provide an overview of the "molecular glue" concept, with a special focus on natural and synthetic inducers of proximity to E3s. We then briefly highlight the serendipitous discoveries of some clinical and preclinical molecular glue degraders, and discuss the first examples of intentional discoveries. Specifically, we outline the different screening strategies reported in this rapidly evolving arena and our thoughts on future perspectives. By mastering the ability to influence PPIs, molecular glue degraders can induce the degradation of unligandable proteins, thus providing an exciting path forward to broaden the targetable proteome.
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Affiliation(s)
- Ana Domostegui
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Luis Nieto-Barrado
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Carles Perez-Lopez
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Cristina Mayor-Ruiz
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
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3
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Regulation of Viral Restriction by Post-Translational Modifications. Viruses 2021; 13:v13112197. [PMID: 34835003 PMCID: PMC8618861 DOI: 10.3390/v13112197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022] Open
Abstract
Intrinsic immunity is orchestrated by a wide range of host cellular proteins called restriction factors. They have the capacity to interfere with viral replication, and most of them are tightly regulated by interferons (IFNs). In addition, their regulation through post-translational modifications (PTMs) constitutes a major mechanism to shape their action positively or negatively. Following viral infection, restriction factor modification can be decisive. Palmitoylation of IFITM3, SUMOylation of MxA, SAMHD1 and TRIM5α or glycosylation of BST2 are some of those PTMs required for their antiviral activity. Nonetheless, for their benefit and by manipulating the PTMs machinery, viruses have evolved sophisticated mechanisms to counteract restriction factors. Indeed, many viral proteins evade restriction activity by inducing their ubiquitination and subsequent degradation. Studies on PTMs and their substrates are essential for the understanding of the antiviral defense mechanisms and provide a global vision of all possible regulations of the immune response at a given time and under specific infection conditions. Our aim was to provide an overview of current knowledge regarding the role of PTMs on restriction factors with an emphasis on their impact on viral replication.
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4
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Kaake RM, Echeverria I, Kim SJ, Von Dollen J, Chesarino NM, Feng Y, Yu C, Ta H, Chelico L, Huang L, Gross J, Sali A, Krogan NJ. Characterization of an A3G-Vif HIV-1-CRL5-CBFβ Structure Using a Cross-linking Mass Spectrometry Pipeline for Integrative Modeling of Host-Pathogen Complexes. Mol Cell Proteomics 2021; 20:100132. [PMID: 34389466 PMCID: PMC8459920 DOI: 10.1016/j.mcpro.2021.100132] [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: 04/15/2021] [Revised: 07/15/2021] [Accepted: 08/04/2021] [Indexed: 10/24/2022] Open
Abstract
Structural analysis of host-pathogen protein complexes remains challenging, largely due to their structural heterogeneity. Here, we describe a pipeline for the structural characterization of these complexes using integrative structure modeling based on chemical cross-links and residue-protein contacts inferred from mutagenesis studies. We used this approach on the HIV-1 Vif protein bound to restriction factor APOBEC3G (A3G), the Cullin-5 E3 ring ligase (CRL5), and the cellular transcription factor Core Binding Factor Beta (CBFβ) to determine the structure of the (A3G-Vif-CRL5-CBFβ) complex. Using the MS-cleavable DSSO cross-linker to obtain a set of 132 cross-links within this reconstituted complex along with the atomic structures of the subunits and mutagenesis data, we computed an integrative structure model of the heptameric A3G-Vif-CRL5-CBFβ complex. The structure, which was validated using a series of tests, reveals that A3G is bound to Vif mostly through its N-terminal domain. Moreover, the model ensemble quantifies the dynamic heterogeneity of the A3G C-terminal domain and Cul5 positions. Finally, the model was used to rationalize previous structural, mutagenesis and functional data not used for modeling, including information related to the A3G-bound and unbound structures as well as mapping functional mutations to the A3G-Vif interface. The experimental and computational approach described here is generally applicable to other challenging host-pathogen protein complexes.
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Affiliation(s)
- Robyn M Kaake
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, California, USA
| | - Ignacia Echeverria
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Seung Joong Kim
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - John Von Dollen
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA
| | - Nicholas M Chesarino
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Yuqing Feng
- Department of Biochemistry, Microbiology, Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Clinton Yu
- Department of Physiology & Biophysics, University of California, Irvine, California, USA
| | - Hai Ta
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Linda Chelico
- Department of Biochemistry, Microbiology, Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lan Huang
- Department of Physiology & Biophysics, University of California, Irvine, California, USA
| | - John Gross
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Andrej Sali
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA; Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, California, USA.
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5
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The Role of APOBECs in Viral Replication. Microorganisms 2020; 8:microorganisms8121899. [PMID: 33266042 PMCID: PMC7760323 DOI: 10.3390/microorganisms8121899] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/14/2022] Open
Abstract
Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like (APOBEC) proteins are a diverse and evolutionarily conserved family of cytidine deaminases that provide a variety of functions from tissue-specific gene expression and immunoglobulin diversity to control of viruses and retrotransposons. APOBEC family expansion has been documented among mammalian species, suggesting a powerful selection for their activity. Enzymes with a duplicated zinc-binding domain often have catalytically active and inactive domains, yet both have antiviral function. Although APOBEC antiviral function was discovered through hypermutation of HIV-1 genomes lacking an active Vif protein, much evidence indicates that APOBECs also inhibit virus replication through mechanisms other than mutagenesis. Multiple steps of the viral replication cycle may be affected, although nucleic acid replication is a primary target. Packaging of APOBECs into virions was first noted with HIV-1, yet is not a prerequisite for viral inhibition. APOBEC antagonism may occur in viral producer and recipient cells. Signatures of APOBEC activity include G-to-A and C-to-T mutations in a particular sequence context. The importance of APOBEC activity for viral inhibition is reflected in the identification of numerous viral factors, including HIV-1 Vif, which are dedicated to antagonism of these deaminases. Such viral antagonists often are only partially successful, leading to APOBEC selection for viral variants that enhance replication or avoid immune elimination.
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6
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Budzik JM, Swaney DL, Jimenez-Morales D, Johnson JR, Garelis NE, Repasy T, Roberts AW, Popov LM, Parry TJ, Pratt D, Ideker T, Krogan NJ, Cox JS. Dynamic post-translational modification profiling of Mycobacterium tuberculosis-infected primary macrophages. eLife 2020; 9:51461. [PMID: 31951200 PMCID: PMC7030789 DOI: 10.7554/elife.51461] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/16/2020] [Indexed: 12/23/2022] Open
Abstract
Macrophages are highly plastic cells with critical roles in immunity, cancer, and tissue homeostasis, but how these distinct cellular fates are triggered by environmental cues is poorly understood. To uncover how primary murine macrophages respond to bacterial pathogens, we globally assessed changes in post-translational modifications of proteins during infection with Mycobacterium tuberculosis, a notorious intracellular pathogen. We identified hundreds of dynamically regulated phosphorylation and ubiquitylation sites, indicating that dramatic remodeling of multiple host pathways, both expected and unexpected, occurred during infection. Most of these cellular changes were not captured by mRNA profiling, and included activation of ubiquitin-mediated autophagy, an evolutionarily ancient cellular antimicrobial system. This analysis also revealed that a particular autophagy receptor, TAX1BP1, mediates clearance of ubiquitylated Mtb and targets bacteria to LC3-positive phagophores. These studies provide a new resource for understanding how macrophages shape their proteome to meet the challenge of infection.
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Affiliation(s)
- Jonathan M Budzik
- Department of Medicine, University of California, San Francisco, San Francisco, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Danielle L Swaney
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States
| | - David Jimenez-Morales
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States.,Department of Medicine, Division of Cardiovascular Medicine, Stanford University, Stanford, United States
| | - Jeffrey R Johnson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States
| | - Nicholas E Garelis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Teresa Repasy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Allison W Roberts
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Lauren M Popov
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Trevor J Parry
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Dexter Pratt
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Trey Ideker
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States
| | - Jeffery S Cox
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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7
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Pan T, Song Z, Wu L, Liu G, Ma X, Peng Z, Zhou M, Liang L, Liu B, Liu J, Zhang J, Zhang X, Huang R, Zhao J, Li Y, Ling X, Luo Y, Tang X, Cai W, Deng K, Li L, Zhang H. USP49 potently stabilizes APOBEC3G protein by removing ubiquitin and inhibits HIV-1 replication. eLife 2019; 8:48318. [PMID: 31397674 PMCID: PMC6701944 DOI: 10.7554/elife.48318] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/08/2019] [Indexed: 12/18/2022] Open
Abstract
The antiviral activity of host factor apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G, A3G) and its degradation mediated by human immunodeficiency virus type 1 (HIV-1) Vif protein are important topics. Although accumulating evidence indicates the importance of deubiquitination enzymes (DUBs) in innate immunity, it is unknown if they participate in A3G stability. Here, we found that USP49 directly interacts with A3G and efficiently removes ubiquitin, consequently increasing A3G protein expression and significantly enhancing its anti-HIV-1 activity. Unexpectedly, A3G degradation was also mediated by a Vif- and cullin-ring-independent pathway, which was effectively counteracted by USP49. Furthermore, clinical data suggested that USP49 is correlated with A3G protein expression and hypermutations in Vif-positive proviruses, and inversely with the intact provirus ratio in the HIV-1 latent reservoir. Our studies demonstrated a mechanism to effectively stabilize A3G expression, which could comprise a target to control HIV-1 infection and eradicate the latent reservoir.
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Affiliation(s)
- Ting Pan
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Zheng Song
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Liyang Wu
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Guangyan Liu
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xiancai Ma
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Zhilin Peng
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Mo Zhou
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Liting Liang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Bingfeng Liu
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Jun Liu
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Junsong Zhang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xuanhong Zhang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Ryan Huang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Jiacong Zhao
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yonghong Li
- Infectious Disease Center, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Xuemei Ling
- Infectious Disease Center, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yuewen Luo
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xiaoping Tang
- Infectious Disease Center, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Weiping Cai
- Infectious Disease Center, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Kai Deng
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Linghua Li
- Infectious Disease Center, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Hui Zhang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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8
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Hüttenhain R, Xu J, Burton LA, Gordon DE, Hultquist JF, Johnson JR, Satkamp L, Hiatt J, Rhee DY, Baek K, Crosby DC, Frankel AD, Marson A, Harper JW, Alpi AF, Schulman BA, Gross JD, Krogan NJ. ARIH2 Is a Vif-Dependent Regulator of CUL5-Mediated APOBEC3G Degradation in HIV Infection. Cell Host Microbe 2019; 26:86-99.e7. [PMID: 31253590 DOI: 10.1016/j.chom.2019.05.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 12/24/2018] [Accepted: 04/26/2019] [Indexed: 12/29/2022]
Abstract
The Cullin-RING E3 ligase (CRL) family is commonly hijacked by pathogens to redirect the host ubiquitin proteasome machinery to specific targets. During HIV infection, CRL5 is hijacked by HIV Vif to target viral restriction factors of the APOBEC3 family for ubiquitination and degradation. Here, using a quantitative proteomics approach, we identify the E3 ligase ARIH2 as a regulator of CRL5-mediated APOBEC3 degradation. The CUL5Vif/CBFß complex recruits ARIH2 where it acts to transfer ubiquitin directly to the APOBEC3 targets. ARIH2 is essential for CRL5-dependent HIV infectivity in primary CD4+ T cells. Furthermore, we show that ARIH2 cooperates with CRL5 to prime other cellular substrates for polyubiquitination, suggesting this may represent a general mechanism beyond HIV infection and APOBEC3 degradation. Taken together, these data identify ARIH2 as a co-factor in the Vif-hijacked CRL5 complex that contributes to HIV infectivity and demonstrate the operation of the E1-E2-E3/E3-substrate ubiquitination mechanism in a viral infection context.
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Affiliation(s)
- Ruth Hüttenhain
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA.
| | - Jiewei Xu
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA
| | - Lily A Burton
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David E Gordon
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA
| | - Judd F Hultquist
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA; Division of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jeffrey R Johnson
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA
| | - Laura Satkamp
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA
| | - Joseph Hiatt
- Gladstone Institutes, San Francisco, CA 94158, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David Y Rhee
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Kheewoong Baek
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - David C Crosby
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Alan D Frankel
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Alexander Marson
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Arno F Alpi
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | | | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nevan J Krogan
- Department of Cellular & Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), San Francisco, CA 94158, USA.
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9
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Role of co-expressed APOBEC3F and APOBEC3G in inducing HIV-1 drug resistance. Heliyon 2019; 5:e01498. [PMID: 31025011 PMCID: PMC6475876 DOI: 10.1016/j.heliyon.2019.e01498] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/24/2019] [Accepted: 04/05/2019] [Indexed: 01/04/2023] Open
Abstract
The APOBEC3 enzymes can induce mutagenesis of HIV-1 proviral DNA through the deamination of cytosine. HIV-1 overcomes this restriction through the viral protein Vif that induces APOBEC3 proteasomal degradation. Within this dynamic host-pathogen relationship, the APOBEC3 enzymes have been found to be beneficial, neutral, or detrimental to HIV-1 biology. Here, we assessed the ability of co-expressed APOBEC3F and APOBEC3G to induce HIV-1 resistance to antiviral drugs. We found that co-expression of APOBEC3F and APOBEC3G enabled partial resistance of APOBEC3F to Vif-mediated degradation with a corresponding increase in APOBEC3F-induced deaminations in the presence of Vif, in addition to APOBEC3G-induced deaminations. We recovered HIV-1 drug resistant variants resulting from APOBEC3-induced mutagenesis, but these variants were less able to replicate than drug resistant viruses derived from RT-induced mutations alone. The data support a model in which APOBEC3 enzymes cooperate to restrict HIV-1, promoting viral inactivation over evolution to drug resistance.
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10
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Molan AM, Hanson HM, Chweya CM, Anderson BD, Starrett GJ, Richards CM, Harris RS. APOBEC3B lysine residues are dispensable for DNA cytosine deamination, HIV-1 restriction, and nuclear localization. Virology 2017; 511:74-81. [PMID: 28841445 DOI: 10.1016/j.virol.2017.08.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 12/11/2022]
Abstract
The APOBEC3 DNA cytosine deaminase family comprises a fundamental arm of the innate immune response and is best known for retrovirus restriction. Several APOBEC3 enzymes restrict HIV-1 and related retroviruses by deaminating viral cDNA cytosines to uracils compromising viral genomes. Human APOBEC3B (A3B) shows strong virus restriction activities in a variety of experimental systems, and is subjected to tight post-translational regulation evidenced by cell-specific HIV-1 restriction activity and active nuclear import. Here we ask whether lysines and/or lysine post-translational modifications are required for these A3B activities. A lysine-free derivative of human A3B was constructed and shown to be indistinguishable from the wild-type enzyme in DNA cytosine deamination, HIV-1 restriction, and nuclear localization activities. However, lysine loss did render the protein resistant to degradation by SIV Vif. Taken together, we conclude that lysine side chains and modifications thereof are unlikely to be central to A3B function or regulation in human cells.
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Affiliation(s)
- Amy M Molan
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Heather M Hanson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cynthia M Chweya
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Brett D Anderson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gabriel J Starrett
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Christopher M Richards
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA.
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11
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Turner T, Shao Q, Wang W, Wang Y, Wang C, Kinlock B, Liu B. Differential Contributions of Ubiquitin-Modified APOBEC3G Lysine Residues to HIV-1 Vif-Induced Degradation. J Mol Biol 2016; 428:3529-39. [PMID: 27297094 DOI: 10.1016/j.jmb.2016.05.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/24/2016] [Accepted: 05/26/2016] [Indexed: 11/19/2022]
Abstract
Apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (A3G) is a host restriction factor that impedes HIV-1 replication. Viral integrity is salvaged by HIV-1 virion infectivity factor (Vif), which mediates A3G polyubiquitination and subsequent cellular depletion. Previous studies have implied that A3G polyubiquitination is essential for Vif-induced degradation. However, the contribution of polyubiquitination to the rate of A3G degradation remains unclear. Here, we show that A3G polyubiquitination is essential for degradation. Inhibition of ubiquitin-activating enzyme E1 by PYR-41 or blocking the formation of ubiquitin chains by over-expressing the lysine to arginine mutation of ubiquitin K48 (K48R) inhibited A3G degradation. Our A3G mutagenesis study showed that lysine residues 297, 301, 303, and 334 were not sufficient to render lysine-free A3G sensitive to Vif-mediated degradation. Our data also confirm that Vif could induce ubiquitin chain formation on lysine residues interspersed throughout A3G. Notably, A3G degradation relied on the lysine residues involved in polyubiquitination. Although A3G and the A3G C-terminal mutant interacted with Vif and were modified by ubiquitin chains, the latter remained more resistant to Vif-induced degradation. Furthermore, the A3G C-terminal mutant, but not the N-terminal mutant, maintained potent antiviral activity in the presence of Vif. Taken together, our results suggest that the location of A3G ubiquitin modification is a determinant for Vif-mediated degradation, implying that in addition to polyubiquitination, other factors may play a key role in the rate of A3G degradation.
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Affiliation(s)
- Tiffany Turner
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - Qiujia Shao
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - Weiran Wang
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA; National Engineering Laboratory for AIDS Vaccine, School of Life Science, Jilin University, Changchun, Jilin Province 130000, People's Republic of China
| | - Yudi Wang
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - Chenliang Wang
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - Ballington Kinlock
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - Bindong Liu
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA.
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12
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Ball KA, Johnson JR, Lewinski MK, Guatelli J, Verschueren E, Krogan NJ, Jacobson MP. Non-degradative Ubiquitination of Protein Kinases. PLoS Comput Biol 2016; 12:e1004898. [PMID: 27253329 PMCID: PMC4890936 DOI: 10.1371/journal.pcbi.1004898] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/02/2016] [Indexed: 12/22/2022] Open
Abstract
Growing evidence supports other regulatory roles for protein ubiquitination in addition to serving as a tag for proteasomal degradation. In contrast to other common post-translational modifications, such as phosphorylation, little is known about how non-degradative ubiquitination modulates protein structure, dynamics, and function. Due to the wealth of knowledge concerning protein kinase structure and regulation, we examined kinase ubiquitination using ubiquitin remnant immunoaffinity enrichment and quantitative mass spectrometry to identify ubiquitinated kinases and the sites of ubiquitination in Jurkat and HEK293 cells. We find that, unlike phosphorylation, ubiquitination most commonly occurs in structured domains, and on the kinase domain, ubiquitination is concentrated in regions known to be important for regulating activity. We hypothesized that ubiquitination, like other post-translational modifications, may alter the conformational equilibrium of the modified protein. We chose one human kinase, ZAP-70, to simulate using molecular dynamics with and without a monoubiquitin modification. In Jurkat cells, ZAP-70 is ubiquitinated at several sites that are not sensitive to proteasome inhibition and thus may have other regulatory roles. Our simulations show that ubiquitination influences the conformational ensemble of ZAP-70 in a site-dependent manner. When monoubiquitinated at K377, near the C-helix, the active conformation of the ZAP-70 C-helix is disrupted. In contrast, when monoubiquitinated at K476, near the kinase hinge region, an active-like ZAP-70 C-helix conformation is stabilized. These results lead to testable hypotheses that ubiquitination directly modulates kinase activity, and that ubiquitination is likely to alter structure, dynamics, and function in other protein classes as well. Attachment of ubiquitin to another protein is typically used to mark the protein for degradation by the proteasome. However, recent studies show that many proteins are tagged with ubiquitin and not degraded. We hypothesized that ubiquitin can regulate the protein it is attached to by changing its structure and dynamics. We performed proteomics experiments to identify all of the kinase proteins tagged by ubiquitin in a human cell line as well as the site of ubiquitination. We found that kinases are often ubiquitinated in structured regions important for regulation and activity. We then performed molecular dynamics simulations of one kinase, ZAP-70, to see if a ubiquitin tag could affect the kinase structure. We found that ubiquitin does affect the structure of ZAP-70, and the effect depends on where the ubiquitin is attached. At K377, ubiquitin changes the ZAP-70 structure to resemble the inactive state, while ubiquitin attached at K476, on the other side of the protein, has the opposite effect. These simulations indicate that ubiquitin, like other post-translational modifications, may alter the structure and dynamics of proteins in ways that impact activity and function.
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Affiliation(s)
- K. Aurelia Ball
- Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California, United States of America
| | - Jeffrey R. Johnson
- Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States of America
| | - Mary K. Lewinski
- Division of Infectious Diseases, University of California at San Diego School of Medicine, La Jolla, California, United States of America
| | - John Guatelli
- Division of Infectious Diseases, University of California at San Diego School of Medicine, La Jolla, California, United States of America
| | - Erik Verschueren
- Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States of America
| | - Nevan J. Krogan
- Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States of America
- * E-mail: (NJK); (MPJ)
| | - Matthew P. Jacobson
- Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California, United States of America
- * E-mail: (NJK); (MPJ)
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13
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Shandilya SMD, Bohn MF, Schiffer CA. A computational analysis of the structural determinants of APOBEC3's catalytic activity and vulnerability to HIV-1 Vif. Virology 2014; 471-473:105-16. [PMID: 25461536 PMCID: PMC4857191 DOI: 10.1016/j.virol.2014.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 11/23/2022]
Abstract
APOBEC3s (A3) are Zn(2+) dependent cytidine deaminases with diverse biological functions and implications for cancer and immunity. Four of the seven human A3s restrict HIV by 'hypermutating' the reverse-transcribed viral genomic DNA. HIV Virion Infectivity Factor (Vif) counters this restriction by targeting A3s to proteasomal degradation. However, there is no apparent correlation between catalytic activity, Vif binding, and sequence similarity between A3 domains. Our comparative structural analysis reveals features required for binding Vif and features influencing polynucleotide deaminase activity in A3 proteins. All Vif-binding A3s share a negatively charged surface region that includes residues previously implicated in binding the highly-positively charged Vif. Additionally, catalytically active A3s share a positively charged groove near the Zn(2+) coordinating active site, which may accommodate the negatively charged polynucleotide substrate. Our findings suggest surface electrostatics, as well as the spatial extent of substrate accommodating region, are critical determinants of substrate and Vif binding across A3 proteins with implications for anti-retroviral and anti-cancer therapeutic design.
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Affiliation(s)
- Shivender M D Shandilya
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Markus-Frederik Bohn
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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14
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Luo Y, Muesing MA. Mass spectrometry-based proteomic approaches for discovery of HIV-host interactions. Future Virol 2014; 9:979-992. [PMID: 25544858 DOI: 10.2217/fvl.14.86] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A molecular understanding of viral infection requires a multi-disciplinary approach. Mass spectrometry has emerged as an indispensable tool to investigate the complex and dynamic interactions between HIV-1 and its host. It has been employed to study protein associations, changes in protein abundance and post-translational modifications occurring after viral infection. Here, we review and provide examples of mass spectrometry-based proteomic approaches currently used to explore virus-host interaction. Efforts in this area are certain to accelerate the discovery of the unique molecular strategies utilized by the virus to commandeer the cell as well as mechanisms of host defense.
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Affiliation(s)
- Yang Luo
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, 455 First Avenue 7th Floor, New York, NY 10016, USA
| | - Mark A Muesing
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, 455 First Avenue 7th Floor, New York, NY 10016, USA
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15
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Cullin E3 ligases and their rewiring by viral factors. Biomolecules 2014; 4:897-930. [PMID: 25314029 PMCID: PMC4279162 DOI: 10.3390/biom4040897] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/20/2014] [Accepted: 09/15/2014] [Indexed: 02/06/2023] Open
Abstract
The ability of viruses to subvert host pathways is central in disease pathogenesis. Over the past decade, a critical role for the Ubiquitin Proteasome System (UPS) in counteracting host immune factors during viral infection has emerged. This counteraction is commonly achieved by the expression of viral proteins capable of sequestering host ubiquitin E3 ligases and their regulators. In particular, many viruses hijack members of the Cullin-RING E3 Ligase (CRL) family. Viruses interact in many ways with CRLs in order to impact their ligase activity; one key recurring interaction involves re-directing CRL complexes to degrade host targets that are otherwise not degraded within host cells. Removal of host immune factors by this mechanism creates a more amenable cellular environment for viral propagation. To date, a small number of target host factors have been identified, many of which are degraded via a CRL-proteasome pathway. Substantial effort within the field is ongoing to uncover the identities of further host proteins targeted in this fashion and the underlying mechanisms driving their turnover by the UPS. Elucidation of these targets and mechanisms will provide appealing anti-viral therapeutic opportunities. This review is focused on the many methods used by viruses to perturb host CRLs, focusing on substrate sequestration and viral regulation of E3 activity.
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16
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Feng Y, Baig TT, Love RP, Chelico L. Suppression of APOBEC3-mediated restriction of HIV-1 by Vif. Front Microbiol 2014; 5:450. [PMID: 25206352 PMCID: PMC4144255 DOI: 10.3389/fmicb.2014.00450] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/06/2014] [Indexed: 12/21/2022] Open
Abstract
The APOBEC3 restriction factors are a family of deoxycytidine deaminases that are able to suppress replication of viruses with a single-stranded DNA intermediate by inducing mutagenesis and functional inactivation of the virus. Of the seven human APOBEC3 enzymes, only APOBEC3-D, -F, -G, and -H appear relevant to restriction of HIV-1 in CD4+ T cells and will be the focus of this review. The restriction of HIV-1 occurs most potently in the absence of HIV-1 Vif that induces polyubiquitination and degradation of APOBEC3 enzymes through the proteasome pathway. To restrict HIV-1, APOBEC3 enzymes must be encapsidated into budding virions. Upon infection of the target cell during reverse transcription of the HIV-1 RNA into (-)DNA, APOBEC3 enzymes deaminate cytosines to form uracils in single-stranded (-)DNA regions. Upon replication of the (-)DNA to (+)DNA, the HIV-1 reverse transcriptase incorporates adenines opposite to the uracils thereby inducing C/G to T/A mutations that can functionally inactivate HIV-1. APOBEC3G is the most studied APOBEC3 enzyme and it is known that Vif attempts to thwart APOBEC3 function not only by inducing its proteasomal degradation but also by several degradation-independent mechanisms, such as inhibiting APOBEC3G virion encapsidation, mRNA translation, and for those APOBEC3G molecules that still become virion encapsidated, Vif can inhibit APOBEC3G mutagenic activity. Although most Vif variants can induce efficient degradation of APOBEC3-D, -F, and -G, there appears to be differential sensitivity to Vif-mediated degradation for APOBEC3H. This review examines APOBEC3-mediated HIV restriction mechanisms, how Vif acts as a substrate receptor for a Cullin5 ubiquitin ligase complex to induce degradation of APOBEC3s, and the determinants and functional consequences of the APOBEC3 and Vif interaction from a biological and biochemical perspective.
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Affiliation(s)
- Yuqing Feng
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan Saskatoon, SK, Canada
| | - Tayyba T Baig
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan Saskatoon, SK, Canada
| | - Robin P Love
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan Saskatoon, SK, Canada
| | - Linda Chelico
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan Saskatoon, SK, Canada
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17
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Nowarski R, Prabhu P, Kenig E, Smith Y, Britan-Rosich E, Kotler M. APOBEC3G inhibits HIV-1 RNA elongation by inactivating the viral trans-activation response element. J Mol Biol 2014; 426:2840-53. [PMID: 24859335 DOI: 10.1016/j.jmb.2014.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 10/25/2022]
Abstract
Deamination of cytidine residues in viral DNA is a major mechanism by which APOBEC3G (A3G) inhibits vif-deficient human immunodeficiency virus type 1 (HIV-1) replication. dC-to-dU transition following RNase-H activity leads to viral cDNA degradation, production of non-functional proteins, formation of undesired stop codons and decreased viral protein synthesis. Here, we demonstrate that A3G provides an additional layer of defense against HIV-1 infection dependent on inhibition of proviral transcription. HIV-1 transcription elongation is regulated by the trans-activation response (TAR) element, a short stem-loop RNA structure required for elongation factors binding. Vif-deficient HIV-1-infected cells accumulate short viral transcripts and produce lower amounts of full-length HIV-1 transcripts due to A3G deamination of the TAR apical loop cytidine, highlighting the requirement for TAR loop integrity in HIV-1 transcription. We further show that free single-stranded DNA (ssDNA) termini are not essential for A3G activity and a gap of CCC motif blocked with juxtaposed DNA or RNA on either or 3'+5' ends is sufficient for A3G deamination. These results identify A3G as an efficient mutator and that deamination of (-)SSDNA results in an early block of HIV-1 transcription.
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Affiliation(s)
- Roni Nowarski
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Ponnandy Prabhu
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Edan Kenig
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Yoav Smith
- Genomic Data Analysis Unit, The Hebrew University Hadassah Medical School, Jerusalem 91120, Israel
| | - Elena Britan-Rosich
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel
| | - Moshe Kotler
- Department of Pathology and Lautenberg Center for General and Tumor Immunology, Jerusalem 91120, Israel.
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Catalytic activity of APOBEC3F is required for efficient restriction of Vif-deficient human immunodeficiency virus. Virology 2013; 450-451:49-54. [PMID: 24503066 DOI: 10.1016/j.virol.2013.11.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 10/01/2013] [Accepted: 11/29/2013] [Indexed: 11/21/2022]
Abstract
APOBEC3 proteins are DNA cytosine deaminases that restrict the replication of human immunodeficiency virus deficient in the counterdefense protein Vif. Here, we address the capacity of APOBEC3F to restrict via deaminase-dependent and -independent mechanisms by monitoring spreading infections in diverse T cell lines. Our data indicate that only a deaminase-proficient protein is capable of long-term restriction of Vif-deficient HIV in T cells, analogous to prior reports for APOBEC3G. This indicates that the principal mechanism of APOBEC3F restriction is deaminase-dependent.
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19
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Anania VG, Pham VC, Huang X, Masselot A, Lill JR, Kirkpatrick DS. Peptide level immunoaffinity enrichment enhances ubiquitination site identification on individual proteins. Mol Cell Proteomics 2013; 13:145-56. [PMID: 24142993 PMCID: PMC3879610 DOI: 10.1074/mcp.m113.031062] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Ubiquitination is a process that involves the covalent attachment of the 76-residue ubiquitin protein through its C-terminal di-glycine (GG) to lysine (K) residues on substrate proteins. This post-translational modification elicits a wide range of functional consequences including targeting proteins for proteasomal degradation, altering subcellular trafficking events, and facilitating protein-protein interactions. A number of methods exist for identifying the sites of ubiquitination on proteins of interest, including site-directed mutagenesis and affinity-purification mass spectrometry (AP-MS). Recent publications have also highlighted the use of peptide-level immunoaffinity enrichment of K-GG modified peptides from whole cell lysates for global characterization of ubiquitination sites. Here we investigated the utility of this technique for focused mapping of ubiquitination sites on individual proteins. For a series of membrane-associated and cytoplasmic substrates including erbB-2 (HER2), Dishevelled-2 (DVL2), and T cell receptor α (TCRα), we observed that K-GG peptide immunoaffinity enrichment consistently yielded additional ubiquitination sites beyond those identified in protein level AP-MS experiments. To assess this quantitatively, SILAC-labeled lysates were prepared and used to compare the abundances of individual K-GG peptides from samples prepared in parallel. Consistently, K-GG peptide immunoaffinity enrichment yielded greater than fourfold higher levels of modified peptides than AP-MS approaches. Using this approach, we went on to characterize inducible ubiquitination on multiple members of the T-cell receptor complex that are functionally affected by endoplasmic reticulum (ER) stress. Together, these data demonstrate the utility of immunoaffinity peptide enrichment for single protein ubiquitination site analysis and provide insights into the ubiquitination of HER2, DVL2, and proteins in the T-cell receptor complex.
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