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Sid Ahmed S, Bajak K, Fackler OT. Beyond Impairment of Virion Infectivity: New Activities of the Anti-HIV Host Cell Factor SERINC5. Viruses 2024; 16:284. [PMID: 38400059 PMCID: PMC10892966 DOI: 10.3390/v16020284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Members of the serine incorporator (SERINC) protein family exert broad antiviral activity, and many viruses encode SERINC antagonists to circumvent these restrictions. Significant new insight was recently gained into the mechanisms that mediate restriction and antagonism. In this review, we summarize our current understanding of the mode of action and relevance of SERINC proteins in HIV-1 infection. Particular focus will be placed on recent findings that provided important new mechanistic insights into the restriction of HIV-1 virion infectivity, including the discovery of SERINC's lipid scramblase activity and its antagonism by the HIV-1 pathogenesis factor Nef. We also discuss the identification and implications of several additional antiviral activities by which SERINC proteins enhance pro-inflammatory signaling and reduce viral gene expression in myeloid cells. SERINC proteins emerge as versatile and multifunctional regulators of cell-intrinsic immunity against HIV-1 infection.
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Affiliation(s)
- Samy Sid Ahmed
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; (S.S.A.); (K.B.)
| | - Kathrin Bajak
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; (S.S.A.); (K.B.)
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, 38124 Heidelberg, Germany
| | - Oliver T. Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; (S.S.A.); (K.B.)
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, 38124 Heidelberg, Germany
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2
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Shi Y, Simpson S, Ahmed SK, Chen Y, Tavakoli-Tameh A, Janaka SK, Evans DT, Serra-Moreno R. The Antiviral Factor SERINC5 Impairs the Expression of Non-Self-DNA. Viruses 2023; 15:1961. [PMID: 37766367 PMCID: PMC10537789 DOI: 10.3390/v15091961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
SERINC5 is a restriction factor that becomes incorporated into nascent retroviral particles, impairing their ability to infect target cells. In turn, retroviruses have evolved countermeasures against SERINC5. For instance, the primate lentiviruses (HIV and SIV) use Nef, Moloney Murine Leukemia Virus (MLV) uses GlycoGag, and Equine Infectious Anemia Virus (EIAV) uses S2 to remove SERINC5 from the plasma membrane, preventing its incorporation into progeny virions. Recent studies have shown that SERINC5 also restricts other viruses, such as Hepatitis B Virus (HBV) and Classical Swine Fever Virus (CSFV), although through a different mechanism, suggesting that SERINC5 can interfere with multiple stages of the virus life cycle. To investigate whether SERINC5 can also impact other steps of the replication cycle of HIV, the effects of SERINC5 on viral transcripts, proteins, and virus progeny size were studied. Here, we report that SERINC5 causes significant defects in HIV gene expression, which impacts virion production. While the underlying mechanism is still unknown, we found that the restriction occurs at the transcriptional level and similarly affects plasmid and non-integrated proviral DNA (ectopic or non-self-DNA). However, SERINC5 causes no defects in the expression of viral RNA, host genes, or proviral DNA that is integrated in the cellular genome. Hence, our findings reveal that SERINC5's actions in host defense extend beyond blocking virus entry.
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Affiliation(s)
- Yuhang Shi
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14620, USA; (Y.S.); (S.K.A.); (Y.C.)
| | | | - Shahad K. Ahmed
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14620, USA; (Y.S.); (S.K.A.); (Y.C.)
| | - Yuexuan Chen
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14620, USA; (Y.S.); (S.K.A.); (Y.C.)
| | | | | | - David T. Evans
- Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53792, USA;
- Wisconsin National Primate Research Center, Madison, WI 53715, USA
| | - Ruth Serra-Moreno
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14620, USA; (Y.S.); (S.K.A.); (Y.C.)
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3
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Wang XF, Zhang X, Ma W, Li J, Wang X. Host cell restriction factors of equine infectious anemia virus. Virol Sin 2023; 38:485-496. [PMID: 37419416 PMCID: PMC10436108 DOI: 10.1016/j.virs.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023] Open
Abstract
Equine infectious anemia virus (EIAV) is a member of the lentivirus genus in the Retroviridae family and is considered an animal model for HIV/AIDS research. An attenuated EIAV vaccine, which was successfully developed in the 1970s by classical serial passage techniques, is the first and only lentivirus vaccine that has been widely used to date. Restriction factors are cellular proteins that provide an early line of defense against viral replication and spread by interfering with various critical steps in the viral replication cycle. However, viruses have evolved specific mechanisms to overcome these host barriers through adaptation. The battle between the viruses and restriction factors is actually a natural part of the viral replication process, which has been well studied in human immunodeficiency virus type 1 (HIV-1). EIAV has the simplest genome composition of all lentiviruses, making it an intriguing subject for understanding how the virus employs its limited viral proteins to overcome restriction factors. In this review, we summarize the current literature on the interactions between equine restriction factors and EIAV. The features of equine restriction factors and the mechanisms by which the EIAV counteract the restriction suggest that lentiviruses employ diverse strategies to counteract innate immune restrictions. In addition, we present our insights on whether restriction factors induce alterations in the phenotype of the attenuated EIAV vaccine.
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Affiliation(s)
- Xue-Feng Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Xiangmin Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Weiwei Ma
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Jiwei Li
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Xiaojun Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150069, China.
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4
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Ramdas P, Chande A. SERINC5 Mediates a Postintegration Block to HIV-1 Gene Expression in Macrophages. mBio 2023; 14:e0016623. [PMID: 36976020 PMCID: PMC10127607 DOI: 10.1128/mbio.00166-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/01/2023] [Indexed: 03/29/2023] Open
Abstract
HIV-1 antagonizes SERINC5 by redundant mechanisms, primarily through Nef and additionally via envelope glycoprotein. Paradoxically, HIV-1 preserves Nef function to ensure the exclusion of SERINC5 from virion incorporation regardless of the availability of envelope that can confer resistance, suggesting additional roles of the virion-incorporated host factor. Here, we report an unusual mode of SERINC5 action in inhibiting viral gene expression. This inhibition is observed only in the myeloid lineage cells but not in the cells of epithelial or lymphoid origin. We found that SERINC5-bearing viruses induce the expression of RPL35 and DRAP1 in macrophages, and these host proteins intercept HIV-1 Tat from binding to and recruiting a mammalian capping enzyme (MCE1) to the HIV-1 transcriptional complex. As a result, uncapped viral transcripts are synthesized, leading to the inhibition of viral protein synthesis and subsequent progeny virion biogenesis. Cell-type-specific inhibition of HIV-1 gene expression thus exemplifies a novel antiviral function of virion-incorporated SERINC5. IMPORTANCE In addition to Nef, HIV-1 envelope glycoprotein has been shown to modulate SERINC5-mediated inhibition. Counterintuitively, Nef from the same isolates preserves the ability to prevent SERINC5 incorporation into virions, implying additional functions of the host protein. We identify that virion-associated SERINC5 can manifest an antiviral mechanism independent of the envelope glycoprotein to regulate HIV-1 gene expression in macrophages. This mechanism is exhibited by affecting the viral RNA capping and is plausibly adopted by the host to overcome the envelope glycoprotein-mediated resistance to SERINC5 restriction.
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Affiliation(s)
- Pavitra Ramdas
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
| | - Ajit Chande
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
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5
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Timilsina U, Stavrou S. SERINC5: One antiviral factor to bind them all. PLoS Pathog 2023; 19:e1011076. [PMID: 36656836 PMCID: PMC9851522 DOI: 10.1371/journal.ppat.1011076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Uddhav Timilsina
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, New York, United States of America
| | - Spyridon Stavrou
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, New York, United States of America
- * E-mail:
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6
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Meseguer S, Rubio MP, Lainez B, Pérez-Benavente B, Pérez-Moraga R, Romera-Giner S, García-García F, Martinez-Macias O, Cremades A, Iborra FJ, Candelas-Rivera O, Almazan F, Esplugues E. SARS-CoV-2-encoded small RNAs are able to repress the host expression of SERINC5 to facilitate viral replication. Front Microbiol 2023; 14:1066493. [PMID: 36876111 PMCID: PMC9978209 DOI: 10.3389/fmicb.2023.1066493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 01/26/2023] [Indexed: 02/18/2023] Open
Abstract
Serine incorporator protein 5 (SERINC5) is a key innate immunity factor that operates in the cell to restrict the infectivity of certain viruses. Different viruses have developed strategies to antagonize SERINC5 function but, how SERINC5 is controlled during viral infection is poorly understood. Here, we report that SERINC5 levels are reduced in COVID-19 patients during the infection by SARS-CoV-2 and, since no viral protein capable of repressing the expression of SERINC5 has been identified, we hypothesized that SARS-CoV-2 non-coding small viral RNAs (svRNAs) could be responsible for this repression. Two newly identified svRNAs with predicted binding sites in the 3'-untranslated region (3'-UTR) of the SERINC5 gene were characterized and we found that the expression of both svRNAs during the infection was not dependent on the miRNA pathway proteins Dicer and Argonaute-2. By using svRNAs mimic oligonucleotides, we demonstrated that both viral svRNAs can bind the 3'UTR of SERINC5 mRNA, reducing SERINC5 expression in vitro. Moreover, we found that an anti-svRNA treatment to Vero E6 cells before SARS-CoV-2 infection recovered the levels of SERINC5 and reduced the levels of N and S viral proteins. Finally, we showed that SERINC5 positively controls the levels of Mitochondrial Antiviral Signalling (MAVS) protein in Vero E6. These results highlight the therapeutic potential of targeting svRNAs based on their action on key proteins of the innate immune response during SARS-CoV-2 viral infection.
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Affiliation(s)
- Salvador Meseguer
- Molecular and Cellular Immunology Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Mari-Paz Rubio
- Molecular and Cellular Immunology Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Begoña Lainez
- Molecular and Cellular Immunology Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Beatriz Pérez-Benavente
- Molecular and Cellular Immunology Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Raúl Pérez-Moraga
- Bioinformatics and Biostatistics Unit, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Sergio Romera-Giner
- Bioinformatics and Biostatistics Unit, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Francisco García-García
- Bioinformatics and Biostatistics Unit, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | | | | | - Francisco J Iborra
- Biological Noise and Cell Plasticity Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Associated Unit to Instituto de Biomedicina de Valencia-CSIC, Valencia, Spain
| | - Oscar Candelas-Rivera
- Molecular and Cellular Biology Department, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Fernando Almazan
- Molecular and Cellular Biology Department, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Enric Esplugues
- Molecular and Cellular Immunology Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain.,Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, United States
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7
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Ramirez PW, Vollbrecht T, Acosta FM, Suarez M, Angerstein AO, Wallace J, O' Connell RM, Guatelli J. Nef enhances HIV-1 replication and infectivity independently of SERINC5 in CEM T cells. Virology 2023; 578:154-162. [PMID: 36577173 PMCID: PMC10484624 DOI: 10.1016/j.virol.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/25/2022]
Abstract
A primary function of HIV-1 Nef is the enhancement of viral infectivity and replication. Whether counteraction of the antiretroviral proteins SERINC3 and SERINC5 is the cause of this positive influence on viral growth-rate and infectivity remains unclear. Here, we utilized CRISPR/Cas9 to knockout SERINC3 and SERINC5 in a leukemic CD4-positive T cell line (CEM) that displays nef-related infectivity and growth-rate phenotypes. Viral replication was attenuated in CEM cells infected with HIV-1 lacking Nef (HIV-1ΔNef). This attenuated growth-rate phenotype was observed regardless of whether the coding regions of the serinc3 or serinc5 genes were intact. Moreover, knockout of serinc5 alone or of both serinc5 and serinc3 together failed to restore the infectivity of HIV1ΔNef virions produced from infected CEM cells. Our results corroborate a similar study using another T-lymphoid cell line (MOLT-3) and indicate that the antagonism of SERINC3 and SERINC5 does not fully explain the virology of HIV-1 lacking Nef.
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Affiliation(s)
- Peter W Ramirez
- Department of Biological Sciences, California State University Long Beach, Long Beach, CA, USA.
| | - Thomas Vollbrecht
- Department of Medicine, University of California San Diego, La Jolla, CA, USA; VA San Diego Healthcare System, San Diego, CA, USA
| | - Francisco M Acosta
- Department of Biological Sciences, California State University Long Beach, Long Beach, CA, USA
| | | | - Aaron O Angerstein
- Department of Medicine, University of California San Diego, La Jolla, CA, USA; VA San Diego Healthcare System, San Diego, CA, USA
| | - Jared Wallace
- Division of Microbiology and Immunology, Department of Pathology, The University of Utah, Salt Lake City, UT, USA
| | - Ryan M O' Connell
- Division of Microbiology and Immunology, Department of Pathology, The University of Utah, Salt Lake City, UT, USA
| | - John Guatelli
- Department of Medicine, University of California San Diego, La Jolla, CA, USA; VA San Diego Healthcare System, San Diego, CA, USA
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8
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Identification of a Novel Post-transcriptional Transactivator from the Equine Infectious Anemia Virus. J Virol 2022; 96:e0121022. [PMID: 36448796 PMCID: PMC9769392 DOI: 10.1128/jvi.01210-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
All lentiviruses encode a post-transcriptional transactivator, Rev, which mediates the export of viral mRNA from the nucleus to the cytoplasm and which is required for viral gene expression and viral replication. In the current study, we demonstrate that equine infectious anemia virus (EIAV), an equine lentivirus, encodes a second post-transcriptional transactivator that we designate Grev. Grev is encoded by a novel transcript with a single splicing event that was identified using reverse transcription-PCR (RT-PCR) and RNA-seq in EIAV-infected horse tissues and cells. Grev is about 18 kDa in size, comprises the first 18 amino acids (aa) of Gag protein together with the last 82 aa of Rev, and was detected in EIAV-infected cells. Similar to Rev, Grev is localized to the nucleus, and both are able to mediate the expression of Mat (a recently identified viral protein of unknown function from EIAV), but Rev can mediate the expression of EIAV Gag/Pol, while Grev cannot. We also demonstrate that Grev, similar to Rev, specifically binds to rev-responsive element 2 (RRE-2, located in the first exon of mat mRNAs) to promote nuclear export of mat mRNA via the chromosome region maintenance 1 (CRM1) pathway. However, unlike Rev, whose function depends on its multimerization, we could not detect multimerization of Grev using coimmunoprecipitation (co-IP) or bimolecular fluorescence complementation (BiFC) assays. Together, these data suggest that EIAV encodes two post-transcriptional transactivators, Rev and Grev, with similar, but not identical, functions. IMPORTANCE Nuclear export of viral transcripts is a crucial step for viral gene expression and viral replication in lentiviruses, and this export is regulated by a post-transcriptional transactivator, Rev, that is shared by all lentiviruses. Here, we report that the equine infectious anemia virus (EIAV) encodes a novel viral protein, Grev, and demonstrated that Grev, like Rev, mediates the expression of the viral protein Mat by binding to the first exon of mat mRNAs via the chromosome region maintenance 1 (CRM1) pathway. Grev is encoded by a single-spliced transcript containing two exons, whereas Rev is encoded by a multiple-spliced transcript containing four exons. Moreover, Rev is able to mediate EIAV Gag/Pol expression by binding to rev-responsive element (RRE) located within the Env-coding region, while Grev cannot. Therefore, the present study demonstrates that EIAV encodes two post-transcriptional regulators, Grev and Rev, suggesting that post-transcriptional regulation patterns in lentivirus are diverse and complex.
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9
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Restriction of Influenza A Virus by SERINC5. mBio 2022; 13:e0292322. [PMID: 36409124 PMCID: PMC9765469 DOI: 10.1128/mbio.02923-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Serine incorporator 5 (Ser5), a transmembrane protein, has recently been identified as a host antiviral factor against human immunodeficiency virus (HIV)-1 and gammaretroviruses like murine leukemia viruses (MLVs). It is counteracted by HIV-1 Nef and MLV glycogag. We have investigated whether it has antiviral activity against influenza A virus (IAV), as well as retroviruses. Here, we demonstrated that Ser5 inhibited HIV-1-based pseudovirions bearing IAV hemagglutinin (HA); as expected, the Ser5 effect on this glycoprotein was antagonized by HIV-1 Nef protein. We found that Ser5 inhibited the virus-cell and cell-cell fusion of IAV, apparently by interacting with HA proteins. Most importantly, overexpressed and endogenous Ser5 inhibited infection by authentic IAV. Single-molecular fluorescent resonance energy transfer (smFRET) analysis further revealed that Ser5 both destabilized the pre-fusion conformation of IAV HA and inhibited the coiled-coil formation during membrane fusion. Ser5 is expressed in cultured small airway epithelial cells, as well as in immortal human cell lines. In summary, Ser5 is a host antiviral factor against IAV which acts by blocking HA-induced membrane fusion. IMPORTANCE SERINC5 (Ser5) is a cellular protein which has been found to interfere with the infectivity of HIV-1 and a number of other retroviruses. Virus particles produced in the presence of Ser5 are impaired in their ability to enter new host cells, but the mechanism of Ser5 action is not well understood. We now report that Ser5 also inhibits infectivity of Influenza A virus (IAV) and that it interferes with the conformational changes in IAV hemagglutinin protein involved in membrane fusion and virus entry. These findings indicate that the antiviral function of Ser5 extends to other viruses as well as retroviruses, and also provide some information on the molecular mechanism of its antiviral activity.
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10
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Li W, Zhang Z, Zhang L, Zhou Q, Li Y, Yi L, Ding H, Zhao M, Chen J, Fan S. Interaction of SERINC5 and IFITM1/2/3 regulates the autophagy-apoptosis-immune network under CSFV infection. Virulence 2022; 13:1720-1740. [PMID: 36205528 PMCID: PMC9553151 DOI: 10.1080/21505594.2022.2127241] [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] [Indexed: 11/18/2022] Open
Abstract
The host restriction factor serine incorporator 5 (SERINC5) plays a key role in inhibiting viral activity and has been shown to inhibit classical swine fever virus (CSFV) infection. However, the action of SERINC5 in the interaction between host cells and CSFV remains poorly understood. This study found that SERINC5 represses CSFV-induced autophagy through MAPK1/3-mTOR and AKT-mTOR signalling pathways. Further research showed that SERINC5 promotes apoptosis by repressing autophagy. Likewise, it was demonstrated that SERINC5 interacting proteins IFITM1/2/3 inhibit CSFV replication and regulate autophagy in a lysosomal-associated membrane protein LAMP1-dependent manner. In addition, IFITM1/2/3 interference promotes the NF-κB signalling pathway for potential immunoregulation by inhibiting autophagy. Finally, the functional silencing of IFITM1/2/3 genes was demonstrated to enhance the inhibitory effect of SERINC5 on autophagy. Taken together, These data uncover a novel mechanism through SERINC5 and its interacting proteins IFITM1/2/3, which mediates CSFV replication, and provides new avenues for controlling CSFV.
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Affiliation(s)
- Wenhui Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China.,College of Food Science and Engineering, Shandong Agricultural University, Taian, China
| | - Zilin Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Liangliang Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Qingfeng Zhou
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Wen' s Foodstuffs Group Co, Ltd, Guangdong, China
| | - Yuwan Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Lin Yi
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Hongxing Ding
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China.,Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, Guangzhou, China
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11
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A Novel, Fully Spliced, Accessory Gene in Equine Lentivirus with Distinct Rev-Responsive Element. J Virol 2022; 96:e0098622. [PMID: 36069548 PMCID: PMC9517694 DOI: 10.1128/jvi.00986-22] [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] [Indexed: 11/20/2022] Open
Abstract
All lentiviruses encode the accessory protein Rev, whose main biological function is to mediate the nuclear export of unspliced and incompletely spliced viral transcripts by binding to a viral cis-acting element (termed the Rev-responsive element, RRE) within the env-encoding region. Equine infectious anemia virus (EIAV) is a member of the lentivirus genus in the Retroviridae family and is considered an important model for the study of lentivirus pathogenesis. Here, we identified a novel transcript from the EIAV genome that encoded a viral protein, named Mat, with an unknown function. The transcript mat was fully spliced and comprised parts of the coding regions of MA and TM. Interestingly, the expression of Mat depended on Rev and the chromosome region maintenance 1 (CRM1) pathway. Rev could specifically bind to Mat mRNA to promote its nuclear export. We further identified that the first exon of Mat mRNA, which was located within the Gag-encoding region, acted as an unreported RRE. Altogether, we identified a novel fully spliced transcript mat with an unusual RRE, which interacted with Rev for nuclear export through the CRM1 pathway. These findings updated the EIAV genome structure, highlighted the diversification of posttranscriptional regulation patterns in EIAV, and may help to expand the understanding of gene transcription and expression of lentivirus. IMPORTANCE In lentiviruses, the nuclear export of viral transcripts is an important step in controlling viral gene expression. Generally, the unspliced and incompletely spliced transcripts are exported via the CRM1-dependent export pathway in a process mediated by the viral Rev protein by binding to the Rev-responsive element (RRE) located within the Env-coding region. However, the completely spliced transcripts are exported via an endogenous cellular pathway, which was Rev independent. Here, we identified a novel fully spliced transcript from EIAV and demonstrated that it encoded a viral protein, termed Mat. Interestingly, we determined that the expression of Mat depended on Rev and identified that the first exon of Mat mRNA could specifically bind to Rev and be exported to the cytoplasm, which suggested that the first exon of Mat mRNA was a second RRE of EIAV. These findings provided important insights into the Rev-dependent nuclear export of completely spliced transcripts in lentiviruses.
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12
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Kirschman J, Marin M, Chen YC, Chen J, Herschhorn A, Smith AB, Melikyan GB. SERINC5 Restricts HIV-1 Infectivity by Promoting Conformational Changes and Accelerating Functional Inactivation of Env. Viruses 2022; 14:1388. [PMID: 35891369 PMCID: PMC9323560 DOI: 10.3390/v14071388] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/18/2022] [Accepted: 06/23/2022] [Indexed: 12/16/2022] Open
Abstract
SERINC5 incorporates into HIV-1 particles and inhibits the ability of Env glycoprotein to mediate virus-cell fusion. SERINC5-resistance maps to Env, with primary isolates generally showing greater resistance than laboratory-adapted strains. Here, we examined a relationship between the inhibition of HIV-1 infectivity and the rate of Env inactivation using a panel of SERINC5-resistant and -sensitive HIV-1 Envs. SERINC5 incorporation into pseudoviruses resulted in a faster inactivation of sensitive compared to resistant Env strains. A correlation between fold reduction in infectivity and the rate of inactivation was also observed for multiple Env mutants known to stabilize and destabilize the closed Env structure. Unexpectedly, most mutations disfavoring the closed Env conformation rendered HIV-1 less sensitive to SERINC5. In contrast, functional inactivation of SERINC5-containing viruses was significantly accelerated in the presence of a CD4-mimetic compound, suggesting that CD4 binding sensitizes Env to SERINC5. Using a small molecule inhibitor that selectively targets the closed Env structure, we found that, surprisingly, SERINC5 increases the potency of this compound against a laboratory-adapted Env which prefers a partially open conformation, indicating that SERINC5 may stabilize the closed trimeric Env structure. Our results reveal a complex effect of SERINC5 on Env conformational dynamics that promotes Env inactivation and is likely responsible for the observed restriction phenotype.
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Affiliation(s)
- Junghwa Kirschman
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
| | - Mariana Marin
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Yen-Cheng Chen
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Junhua Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.C.); (A.B.S.III)
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.C.); (A.B.S.III)
| | - Gregory B. Melikyan
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
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13
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SARS-CoV-2 ORF7a potently inhibits the antiviral effect of the host factor SERINC5. Nat Commun 2022; 13:2935. [PMID: 35618710 PMCID: PMC9135752 DOI: 10.1038/s41467-022-30609-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 04/22/2022] [Indexed: 01/03/2023] Open
Abstract
Serine Incorporator 5 (SERINC5), a cellular multipass transmembrane protein that is involved in sphingolipid and phosphatydilserine biogenesis, potently restricts a number of retroviruses, including Human Immunodeficiency Virus (HIV). SERINC5 is incorporated in the budding virions leading to the inhibition of virus infectivity. In turn, retroviruses, including HIV, encode factors that counteract the antiviral effect of SERINC5. While SERINC5 has been well studied in retroviruses, little is known about its role in other viral families. Due to the paucity of information regarding host factors targeting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), we evaluated the effect of SERINC proteins on SARS-CoV-2 infection. Here, we show SERINC5 inhibits SARS-CoV-2 entry by blocking virus-cell fusion, and SARS-CoV-2 ORF7a counteracts the antiviral effect of SERINC5 by blocking the incorporation of over expressed SERINC5 in budding virions. SERINC5, is a cellular multipass transmembrane protein involved in sphingolipid and phosphatydilserine biogenesis and a known retroviral restriction factor. Here, Timilsina et al. show that SERINC5 is a host restriction factor for SARS-CoV-2 that prevents viral fusion during entry. Further they show that viral ORF7a counteracts SERINC5 anti-viral activity by blocking its incorporation into progeny virions.
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14
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Vannamahaxay S, Sornpet B, Pringproa K, Patchanee P, Chuammitri P. Transcriptome analysis of infected Crandell Rees Feline Kidney (CRFK) cells by canine parvovirus type 2c Laotian isolates. Gene X 2022; 822:146324. [PMID: 35182681 DOI: 10.1016/j.gene.2022.146324] [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: 09/26/2021] [Revised: 01/22/2022] [Accepted: 02/11/2022] [Indexed: 11/17/2022] Open
Abstract
The advent of RNA sequencing technology provides insight into the dynamic nature of tremendous transcripts within Crandell-Reese feline kidney (CRFK) cells in response to canine parvovirus (CPV-2c) infection. A total of 1,603 genes displayed differentially expressed genes (DEGs), including 789 up-regulated genes and 814 downregulated genes in the infected cells. Gene expression profiles have shown a subtle pattern of defense mechanism and immune response to CPV through significant DEGs when extensively examined via Gene Ontology (GO) and pathway analysis. Prospective GO analysis was performed and identified several enriched GO biological process terms with significant participating roles in the immune system process and defense response to virus pathway. A Gene network was constructed using the 22 most significantly enriched genes of particular interests in defense response to virus pathways to illustrate the key pathways. Eleven genes (C1QBP, CD40, HYAL2, IFNB1, IFNG, IL12B, IL6, IRF3, LSM14A, MAVS, NLRC5) were identified, which are directly related to the defense response to the virus. Results of transcriptome profiling permit us to understand the heterogeneity of DEGs during in vitro experimental study of CPV infection, reflecting a unique transcriptome signature for the CPV virus. Our findings also demonstrate a distinct scenario of enhanced CPV responses in CRFK cells for viral clearance that involved multistep and perplexity of biological processes. Collectively, our data have given a fundamental role in anti-viral immunity as our highlights of this study, thus providing outlooks on future research priorities to be important in studying CPV.
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Affiliation(s)
- Soulasack Vannamahaxay
- Department of Veterinary Medicine, Faculty of Agriculture, National University of Laos, Vientiane, Lao Democratic People's Republic
| | - Benjaporn Sornpet
- Central Laboratory, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Kidsadagon Pringproa
- Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Prapas Patchanee
- Department of Food Animal Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Integrative Research Center for Veterinary Preventive Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Phongsakorn Chuammitri
- Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Research Center of Producing and Development of Products and Innovations for Animal Health and Production, Chiang Mai University, Chiang Mai 50100, Thailand.
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15
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Li S, Li R, Ahmad I, Liu X, Johnson SF, Sun L, Zheng YH. Cul3-KLHL20 E3 ubiquitin ligase plays a key role in the arms race between HIV-1 Nef and host SERINC5 restriction. Nat Commun 2022; 13:2242. [PMID: 35474067 PMCID: PMC9042822 DOI: 10.1038/s41467-022-30026-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
HIV-1 must counteract various host restrictions to establish productive infection. SERINC5 is a potent restriction factor that blocks HIV-1 entry from virions, but its activity is counteracted by Nef. The SERINC5 and Nef activities are both initiated from the plasma membrane, where SERINC5 is packaged into virions for viral inhibition or downregulated by Nef via lysosomal degradation. However, it is still unclear how SERINC5 is localized to and how its expression is regulated on the plasma membrane. We now report that Cullin 3-KLHL20, a trans-Golgi network (TGN)-localized E3 ubiquitin ligase, polyubiquitinates SERINC5 at lysine 130 via K33/K48-linked ubiquitination. The K33-linked polyubiquitination determines SERINC5 expression on the plasma membrane, and the K48-linked polyubiquitination contributes to SERINC5 downregulation from the cell surface. Our study reveals an important role of K130 polyubiquitination and K33/K48-linked ubiquitin chains in HIV-1 infection by regulating SERINC5 post-Golgi trafficking and degradation. SERINC5 is a host-restriction factor preventing HIV progeny entry, which is counteracted by interactions with HIV Nef. Here, Li et al. show that E3 ubiquitin ligase Cullin 3 polyubiquitinates SERINC5 at Lys 130 via K48- and K33-linked ubiquitin chains and provide evidence that this modification is not only required for its membrane localization and anti-viral activity but also relevant for Nef counteractive activity.
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Affiliation(s)
- Sunan Li
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Rongrong Li
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Iqbal Ahmad
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaomeng Liu
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Silas F Johnson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Yong-Hui Zheng
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China. .,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
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16
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Xu S, Zheng Z, Pathak JL, Cheng H, Zhou Z, Chen Y, Wu Q, Wang L, Zeng M, Wu L. The Emerging Role of the Serine Incorporator Protein Family in Regulating Viral Infection. Front Cell Dev Biol 2022; 10:856468. [PMID: 35433679 PMCID: PMC9010877 DOI: 10.3389/fcell.2022.856468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/09/2022] [Indexed: 11/25/2022] Open
Abstract
Serine incorporator (SERINC) proteins 1–5 (SERINC1-5) are involved in the progression of several diseases. SERINC2-4 are carrier proteins that incorporate the polar amino acid serine into membranes to facilitate the synthesis of phosphatidylserine and sphingolipids. SERINC genes are also differentially expressed in tumors. Abnormal expression of SERINC proteins occurs in human cancers of the breast, lung, colon, liver, and various glands, as well as in mouse testes. SERINC proteins also affect cleft lip and palate and nerve-related diseases, such as seizure Parkinsonism and borderline personality. Moreover, SERINC proteins have garnered significant interest as retroviral restriction factors, spurring efforts to define their function and elucidate the mechanisms through which they operate when associated with viruses. Human SERINC proteins possess antiviral potential against human immunodeficiency virus (HIV), SARS-COV-2, murine leukemia virus (MLV), equine infectious anemia virus (EIAV), and hepatitis B virus (HBV). Furthermore, the crystal structure is known, and the critical residues of SERINC5 that act against HIV have been identified. In this review, we discuss the most prevalent mechanisms by which SERINC3 and SERINC5 antagonize viruses and focus on the potential therapeutic applications of SERINC5/3 against HIV.
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Affiliation(s)
- Shaofen Xu
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhichao Zheng
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Basic Oral Medicine, Guangzhou Medical University School and Hospital of Stomatology, Guangzhou, China
| | - Janak L. Pathak
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Haoyu Cheng
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ziliang Zhou
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yanping Chen
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Qiuyu Wu
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Lijing Wang
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Vascular Biology Research Institute, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, China
- *Correspondence: Lihong Wu, ; Mingtao Zeng, ; Lijing Wang,
| | - Mingtao Zeng
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- *Correspondence: Lihong Wu, ; Mingtao Zeng, ; Lijing Wang,
| | - Lihong Wu
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Basic Oral Medicine, Guangzhou Medical University School and Hospital of Stomatology, Guangzhou, China
- *Correspondence: Lihong Wu, ; Mingtao Zeng, ; Lijing Wang,
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17
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Cano-Ortiz L, Luedde T, Münk C. HIV-1 restriction by SERINC5. Med Microbiol Immunol 2022; 212:133-140. [PMID: 35333966 PMCID: PMC10085909 DOI: 10.1007/s00430-022-00732-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/08/2022] [Indexed: 11/25/2022]
Abstract
Serine incorporator 5 (SERINC5 or SER5) is a multipass transmembrane protein with ill-defined cellular activities. SER5 was recently described as a human immunodeficiency virus 1 (HIV-1) restriction factor capable of inhibiting HIV-1 that does not express its accessory protein Nef (Δ Nef). SER5 incorporated into the viral membrane impairs the entry of HIV-1 by disrupting the fusion between the viral and the plasma membrane after envelope receptor interaction induced the first steps of the fusion process. The mechanisms of how SER5 prevents membrane fusion are not fully understood and viral envelope proteins were identified that escape the SER5-mediated restriction. Primate lentiviruses, such as HIV-1 and simian immunodeficiency viruses (SIVs), use their accessory protein Nef to downregulate SER5 from the plasma membrane by inducing an endocytic pathway. In addition to being directly antiviral, recent data suggest that SER5 is an important adapter protein in innate signaling pathways leading to the induction of inflammatory cytokines. This review discusses the current knowledge about HIV-1 restriction by SER5.
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Affiliation(s)
- Lucía Cano-Ortiz
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Building 23.12.U1.82, Moorenstr. 5, 40225, Düsseldorf, Germany
- Laboratório de Virologia, Departamento de Microbiologia, Imunologia e Parasitologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Tom Luedde
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Building 23.12.U1.82, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Carsten Münk
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Building 23.12.U1.82, Moorenstr. 5, 40225, Düsseldorf, Germany.
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18
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Cano-Ortiz L, Gu Q, de Sousa-Pereira P, Zhang Z, Chiapella C, Penda Twizerimana A, Lin C, Cláudia Franco A, VandeWoude S, Luedde T, Baldauf HM, Münk C. Feline Leukemia Virus-B Envelope together with its GlycoGag and Human Immunodeficiency Virus-1 Nef Mediate Resistance to Feline SERINC5. J Mol Biol 2021; 434:167421. [DOI: 10.1016/j.jmb.2021.167421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 11/29/2022]
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19
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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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20
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Zeng C, Waheed AA, Li T, Yu J, Zheng YM, Yount JS, Wen H, Freed EO, Liu SL. SERINC proteins potentiate antiviral type I IFN production and proinflammatory signaling pathways. Sci Signal 2021; 14:eabc7611. [PMID: 34520227 DOI: 10.1126/scisignal.abc7611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Cong Zeng
- Center for Retrovirus Research, Ohio State University, Columbus, OH 43210, USA.,Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210, USA
| | - Abdul A Waheed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Frederick, MD 21702, USA
| | - Tianliang Li
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA
| | - Jingyou Yu
- Center for Retrovirus Research, Ohio State University, Columbus, OH 43210, USA.,Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210, USA
| | - Yi-Min Zheng
- Center for Retrovirus Research, Ohio State University, Columbus, OH 43210, USA.,Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210, USA
| | - Jacob S Yount
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA
| | - Haitao Wen
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Frederick, MD 21702, USA
| | - Shan-Lu Liu
- Center for Retrovirus Research, Ohio State University, Columbus, OH 43210, USA.,Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210, USA.,Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA.,Viruses and Emerging Pathogens Program, Infectious Diseases Institute, Ohio State University, Columbus, OH 43210, USA
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21
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Aromatic Side Chain at Position 412 of SERINC5 Exerts Restriction Activity toward HIV-1 and Other Retroviruses. J Virol 2021; 95:e0063421. [PMID: 34190600 DOI: 10.1128/jvi.00634-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The host transmembrane protein SERINC5 is incorporated into viral particles and restricts infection by certain retroviruses. However, what motif of SERINC5 mediates this process remains elusive. By conducting mutagenesis analyses, we found that the substitution of phenylalanine with alanine at position 412 (F412A) resulted in a >75-fold reduction in SERINC5's restriction function. The F412A substitution also resulted in the loss of SERINC5's function to sensitize HIV-1 neutralization by antibodies recognizing the envelope's membrane proximal region. A series of biochemical analyses revealed that F412A showed steady-state protein expression, localization at the cellular membrane, and incorporation into secreted virus particles to a greater extent than in the wild type. Furthermore, introduction of several amino acid mutations at this position revealed that the aromatic side chains, including phenylalanine, tyrosine, and tryptophan, were required to maintain SERINC5 functions to impair the virus-cell fusion process and virion infectivity. Moreover, the wild-type SERINC5 restricted infection of lentiviruses pseudotyped with envelopes of murine leukemia viruses, simian immunodeficiency virus, and HIV-2, and F412A abrogated this function. Taken together, our results highlight the importance of the aromatic side chain at SERINC5 position 412 to maintain its restriction function against diverse retrovirus envelopes. IMPORTANCE The host protein SERINC5 is incorporated into progeny virions of certain retroviruses and restricts the infectivity of these viruses or sensitizes the envelope glycoprotein to a class of neutralizing antibodies. However, how and which part of SERINC5 engages with the diverse array of retroviral envelopes and exerts its antiretroviral functions remain elusive. During mutagenesis analyses, we eventually found that the single substitution of phenylalanine with alanine, but not with tyrosine or tryptophan, at position 412 (F412A) resulted in the loss of SERINC5's functions toward diverse retroviruses, whereas F412A showed steady-state protein expression, localization at the cellular membrane, and incorporation into progeny virions to a greater extent than the wild type. Results suggest that the aromatic side chain at position 412 of SERINC5 plays a critical role in mediating antiviral functions toward various retroviruses, thus providing additional important information regarding host and retrovirus interaction.
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22
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Chai Q, Li S, Collins MK, Li R, Ahmad I, Johnson SF, Frabutt DA, Yang Z, Shen X, Sun L, Hu J, Hultquist JF, Peterlin BM, Zheng YH. HIV-1 Nef interacts with the cyclin K/CDK13 complex to antagonize SERINC5 for optimal viral infectivity. Cell Rep 2021; 36:109514. [PMID: 34380030 PMCID: PMC8385645 DOI: 10.1016/j.celrep.2021.109514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 06/17/2021] [Accepted: 07/20/2021] [Indexed: 11/03/2022] Open
Abstract
HIV-1-negative factor (Nef) protein antagonizes serine incorporator 5 (SERINC5) by redirecting this potent restriction factor to the endosomes and lysosomes for degradation. However, the precise mechanism remains unclear. Using affinity purification/mass spectrometry, we identify cyclin K (CycK) and cyclin-dependent kinase 13 (CDK13) as a Nef-associated kinase complex. CycK/CDK13 phosphorylates the serine at position 360 (S360) in SERINC5, which is required for Nef downregulation of SERINC5 from the cell surface and its counteractivity of the SERINC5 antiviral activity. To understand the role of S360 phosphorylation, we generate chimeric proteins between CD8 and SERINC5 to study their response to Nef. Nef not only downregulates but, importantly, also binds to this chimera in an S360-dependent manner. Thus, S360 phosphorylation increases interactions between Nef and SERINC5 and initiates the destruction of SERINC5 by the endocytic machinery.
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Affiliation(s)
- Qingqing Chai
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Sunan Li
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Morgan K Collins
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Rongrong Li
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Iqbal Ahmad
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Silas F Johnson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA; Department of Biology, Hillsdale College, Hillsdale, MI, USA
| | - Dylan A Frabutt
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Zhichang Yang
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Xiaojing Shen
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Jian Hu
- Department of Chemistry, Michigan State University, East Lansing, MI, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Judd F Hultquist
- Division of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - B Matija Peterlin
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Yong-Hui Zheng
- Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, China; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
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23
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Molnar S, Wieczorek L, Zemil M, Schulte B, Martinez E, Gift S, Tang L, Streeck H, Gramzinski RA, Michael NL, Joyce G, Polonis VR. Novel monoclonal antibodies to the SERINC5 HIV-1 restriction factor detect endogenous andvirion-associated SERINC5. MAbs 2021; 12:1802187. [PMID: 32835602 PMCID: PMC7531522 DOI: 10.1080/19420862.2020.1802187] [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] [Indexed: 01/06/2023] Open
Abstract
SERINC5 is a multi-pass transmembrane protein that is thought to play a role in serine incorporation during cellular membrane biosynthesis. This protein has also been identified as a human immunodeficiency virus Type 1 (HIV-1) restriction factor. The paucity of monoclonal antibodies (mAbs) against SERINC5 has posed a challenge for the study of the endogenous protein. Here we report the development of novel anti-SERINC5 mAbs that target three distinct loops on the protein. We demonstrate that these SERINC5 mAbs can be used to detect endogenously expressed SERINC5 protein in various cell lines using Western blot, whole-cell ELISA, flow cytometry, and immunocytochemistry. We further show that some of these antibodies can detect SERINC5 that is present in HIV-1 viral stocks. These antibodies will aid in the characterization of the functions and mechanisms of action of SERINC5 in different cell types.
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Affiliation(s)
- Sebastian Molnar
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD, USA
| | - Lindsay Wieczorek
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD, USA
| | - Michelle Zemil
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD, USA
| | - Bianca Schulte
- Institute for Virology, University Hospital Bonn , Bonn, Germany
| | - Elizabeth Martinez
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD, USA
| | - Syna Gift
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD, USA
| | - Lan Tang
- Biologics Department, GenScript , Piscataway, NJ, USA
| | - Hendrik Streeck
- Institute for Virology, University Hospital Bonn , Bonn, Germany
| | - Robert A Gramzinski
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA
| | - Nelson L Michael
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA
| | - Gordon Joyce
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD, USA
| | - Victoria R Polonis
- Military HIV Research Program, Walter Reed Army Institute of Research , Silver Spring, MD, USA
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Influence of Different Glycoproteins and of the Virion Core on SERINC5 Antiviral Activity. Viruses 2021; 13:v13071279. [PMID: 34209034 PMCID: PMC8310182 DOI: 10.3390/v13071279] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/22/2021] [Accepted: 06/28/2021] [Indexed: 11/25/2022] Open
Abstract
Host plasma membrane protein SERINC5 is incorporated into budding retrovirus particles where it blocks subsequent entry into susceptible target cells. Three structurally unrelated proteins encoded by diverse retroviruses, human immunodeficiency virus type 1 (HIV-1) Nef, equine infectious anemia virus (EIAV) S2, and ecotropic murine leukemia virus (MLV) GlycoGag, disrupt SERINC5 antiviral activity by redirecting SERINC5 from the site of virion assembly on the plasma membrane to an internal RAB7+ endosomal compartment. Pseudotyping retroviruses with particular glycoproteins, e.g., vesicular stomatitis virus glycoprotein (VSV G), renders the infectivity of particles resistant to inhibition by virion-associated SERINC5. To better understand viral determinants for SERINC5-sensitivity, the effect of SERINC5 was assessed using HIV-1, MLV, and Mason-Pfizer monkey virus (M-PMV) virion cores, pseudotyped with glycoproteins from Arenavirus, Coronavirus, Filovirus, Rhabdovirus, Paramyxovirus, and Orthomyxovirus genera. SERINC5 restricted virions pseudotyped with glycoproteins from several retroviruses, an orthomyxovirus, a rhabdovirus, a paramyxovirus, and an arenavirus. Infectivity of particles pseudotyped with HIV-1, amphotropic-MLV (A-MLV), or influenza A virus (IAV) glycoproteins, was decreased by SERINC5, whether the core was provided by HIV-1, MLV, or M-PMV. In contrast, particles pseudotyped with glycoproteins from M-PMV, parainfluenza virus 5 (PIV5), or rabies virus (RABV) were sensitive to SERINC5, but only with particular retroviral cores. Resistance to SERINC5 did not correlate with reduced SERINC5 incorporation into particles, route of viral entry, or absolute infectivity of the pseudotyped virions. These findings indicate that some non-retroviruses may be sensitive to SERINC5 and that, in addition to the viral glycoprotein, the retroviral core influences sensitivity to SERINC5.
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25
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Coelacanth SERINC2 Inhibits HIV-1 Infectivity and Is Counteracted by Envelope Glycoprotein from Foamy Virus. J Virol 2021; 95:e0022921. [PMID: 33883219 PMCID: PMC8316019 DOI: 10.1128/jvi.00229-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
SERINC5 restricts nef-defective HIV-1 by affecting early steps of the virus life cycle. Distantly related retroviruses with a wide host range encode virulent factors in response to challenge by SERINC5. However, the evolutionary origins of this antiretroviral activity, its prevalence among the paralogs, and its ability to target retroviruses remain understudied. In agreement with previous studies, we found that four human SERINC paralogs inhibit nef-defective HIV-1, with SERINC2 being an exception. Here, we demonstrate that this lack of activity in human SERINC2 is associated with its post-whole-genome duplication (post-WGD) divergence, as evidenced by the ability of pre-WGD orthologs from Saccharomyces cerevisiae and flies and a post-WGD-proximate SERINC2 from coelacanths to inhibit the virus. Intriguingly, Nef is unable to counter coelacanth SERINC2, indicating that such activity was directed toward other retroviruses found in coelacanths (like foamy viruses). However, foamy virus-derived vectors are intrinsically resistant to the action of SERINC2, and we show that the foamy virus envelope confers this resistance by affecting its steady-state levels. Our study highlights an ancient origin of antiretroviral activity in SERINCs and a hitherto-unknown interaction with a foamy virus. IMPORTANCESERINC5 constitutes a critical barrier to the propagation of retroviruses, as highlighted by parallel emergence of anti-SERINC5 activities among distant retroviral lineages. Therefore, understanding the origin and evolution of these host factors will provide key information about virus-host relationships that can be exploited for future drug development. Here, we show that SERINC5-mediated nef-defective HIV-1 infection inhibition is evolutionarily conserved. SERINC2 from coelacanth restricts HIV-1, and it was functionally adapted to target foamy viruses. Our findings provide insights into the evolutionary origin of antiretroviral activity in the SERINC gene family and uncover the role of SERINCs in shaping the long-term conflicts between retroviruses and their hosts.
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26
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Mishra T, Sreepadmanabh M, Ramdas P, Sahu AK, Kumar A, Chande A. SARS CoV-2 Nucleoprotein Enhances the Infectivity of Lentiviral Spike Particles. Front Cell Infect Microbiol 2021; 11:663688. [PMID: 33968806 PMCID: PMC8102828 DOI: 10.3389/fcimb.2021.663688] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/08/2021] [Indexed: 12/11/2022] Open
Abstract
The establishment of SARS CoV-2 spike-pseudotyped lentiviral (LV) systems has enabled the rapid identification of entry inhibitors and neutralizing agents, alongside allowing for the study of this emerging pathogen in BSL-2 level facilities. While such frameworks recapitulate the cellular entry process in ACE2+ cells, they are largely unable to factor in supplemental contributions by other SARS CoV-2 genes. To address this, we performed an unbiased ORF screen and identified the nucleoprotein (N) as a potent enhancer of spike-pseudotyped LV particle infectivity. We further demonstrate that the spike protein is better enriched in virions when the particles are produced in the presence of N protein. This enrichment of spike renders LV particles more infectious as well as less vulnerable to the neutralizing effects of a human IgG-Fc fused ACE2 microbody. Importantly, this improvement in infectivity is observed with both wild-type spike protein as well as the D614G mutant. Our results hold important implications for the design and interpretation of similar LV pseudotyping-based studies.
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Affiliation(s)
- Tarun Mishra
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - M Sreepadmanabh
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Pavitra Ramdas
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Amit Kumar Sahu
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Atul Kumar
- Structural Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Ajit Chande
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
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27
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Selective Disruption of SERINC5 Antagonism by Nef Impairs SIV Replication in Primary CD4 + T Cells. J Virol 2021; 95:JVI.01911-20. [PMID: 33504599 PMCID: PMC8103682 DOI: 10.1128/jvi.01911-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Nef proteins of HIV-1 and SIV enhance viral infectivity by preventing the incorporation of the multipass transmembrane protein serine incorporator 5 (SERINC5), and to a lesser extent SERINC3, into virions. In addition to counteracting SERINCs, SIV Nef also downmodulates several transmembrane proteins from the surface of virus-infected cells, including simian tetherin, CD4 and MHC class I (MHC I) molecules. From a systematic analysis of alanine substitutions throughout the SIVmac239 Nef protein, we identified residues that are required to counteract SERINC5. This information was used to engineer an infectious molecular clone of SIV (SIVmac239nef AV), which differs by two amino acids in the N-terminal domain of Nef that make the virus sensitive to SERINC5 while retaining other activities of Nef. SIVmac239nef AV downmodulates CD3, CD4, MHC I and simian tetherin, but cannot counteract SERINC5. In primary rhesus macaque CD4+ T cells, SIVmac239nef AV exhibits impaired infectivity and replication compared to wild-type SIVmac239. These results demonstrate that SERINC5 antagonism can be separated from other Nef functions and reveal the impact of SERINC5 on lentiviral replication.Importance: SERINC5, a multipass transmembrane protein, is incorporated into retroviral particles during assembly. This leads to a reduction of particle infectivity by inhibiting virus fusion with the target cell membrane. The Nef proteins of HIV-1 and SIV enhance viral infectivity by preventing the incorporation of SERINC5 into virions. However, the relevance of this restriction factor in viral replication has not been elucidated. Here we report a systematic mapping of Nef residues required for SERINC5 antagonism. Counter screens for three other functions of Nef helped identify two residues in the N-terminal domain of Nef, which when mutated make Nef selectively susceptible to SERINC5. Since Nef is multi-functional, genetic separation of SERINC5 antagonism from its other functions affords comparison of the replication of isogenic viruses that are or are not sensitive to SERINC5. Such a strategy revealed the impact of SERINC5 on SIV replication in primary rhesus macaque CD4+ T-cells.
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28
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Jaguva Vasudevan AA, Balakrishnan K, Franken A, Krikoni A, Häussinger D, Luedde T, Münk C. Murine leukemia virus resists producer cell APOBEC3A by its Glycosylated Gag but not target cell APOBEC3A. Virology 2021; 557:1-14. [PMID: 33581610 DOI: 10.1016/j.virol.2021.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 12/14/2022]
Abstract
The human APOBEC3A (A3A) polynucleotide cytidine deaminase has been shown to have antiviral activity against HTLV-1 but not HIV-1, when expressed in the virus producer cell. In viral target cells, high levels of endogenous A3A activity have been associated with the restriction of HIV-1 during infection. Here we demonstrate that A3A derived from both target cells and producer cells can block the infection of Moloney-MLV (MLV) and related AKV-derived strains of MLV in a deaminase-dependent mode. Furthermore, glycosylated Gag (glycoGag) of MLV inhibits the encapsidation of human A3A, but target cell A3A was not affected by glycoGag and exerted deamination of viral DNA. Importantly, our results clearly indicate that poor glycoGag expression in MLV gag-pol packaging constructs as compared to abundant levels in full-length amphotropic MLV makes these viral vectors sensitive to A3A-mediated restriction. This raises the possibility of acquiring A3A-induced mutations in retroviral gene therapy applications.
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Affiliation(s)
- Ananda Ayyappan Jaguva Vasudevan
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany.
| | - Kannan Balakrishnan
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany; Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - André Franken
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Aikaterini Krikoni
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Tom Luedde
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Carsten Münk
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany.
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29
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Retroviral Restriction Factors and Their Viral Targets: Restriction Strategies and Evolutionary Adaptations. Microorganisms 2020; 8:microorganisms8121965. [PMID: 33322320 PMCID: PMC7764263 DOI: 10.3390/microorganisms8121965] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/30/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022] Open
Abstract
The evolutionary conflict between retroviruses and their vertebrate hosts over millions of years has led to the emergence of cellular innate immune proteins termed restriction factors as well as their viral antagonists. Evidence accumulated in the last two decades has substantially increased our understanding of the elaborate mechanisms utilized by these restriction factors to inhibit retroviral replication, mechanisms that either directly block viral proteins or interfere with the cellular pathways hijacked by the viruses. Analyses of these complex interactions describe patterns of accelerated evolution for these restriction factors as well as the acquisition and evolution of their virus-encoded antagonists. Evidence is also mounting that many restriction factors identified for their inhibition of specific retroviruses have broader antiviral activity against additional retroviruses as well as against other viruses, and that exposure to these multiple virus challenges has shaped their adaptive evolution. In this review, we provide an overview of the restriction factors that interfere with different steps of the retroviral life cycle, describing their mechanisms of action, adaptive evolution, viral targets and the viral antagonists that evolved to counter these factors.
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30
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Qiu X, Eke IE, Johnson SF, Ding C, Zheng YH. Proteasomal degradation of human SERINC4: A potent host anti-HIV-1 factor that is antagonized by nef. ACTA ACUST UNITED AC 2020; 1. [PMID: 33521797 PMCID: PMC7842267 DOI: 10.1016/j.crviro.2020.100002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The serine incorporator (SERINC) protein family has five paralogous members with 9–11 transmembrane domains. SERINC5 is a potent host restriction factor and antagonized by HIV-1 Nef and two other retroviral accessory proteins via the lysosomal degradation pathway. Here, we investigated human SERINC4 expression and antiviral mechanisms. Unlike its four paralogs, human SERINC4 is subjected to proteasome-mediated turnover, resulting in ~250-fold lower expression than SERINC5. However, when expression was normalized, human SERINC4 restricted HIV-1 replication as effectively as SERINC5, and SERINC4 was also antagonized by Nef via the lysosomal pathway. Although SERINC4 proteins are conserved within primates or rodents, their N-terminal regions are highly variable across species. Interestingly, unlike human SERINC4, murine SERINC4 was stably expressed but had a very poor antiviral activity. We created stable SERINC4 chimeras by replacing the N-terminal region and found that the 1–34 and 35–92 amino acids determine SERINC4 antiviral activity or protein expression, respectively. Using these chimeras, we demonstrate that SERINC4 is incorporated into HIV-1 virions and restricts Tier 1 HIV-1 more effectively than Tier 3 HIV-1. Importantly, SERINC4 increases HIV-1 sensitivity to broadly neutralizing antibodies. Thus, human SERINC4 strongly restricts HIV-1 replication when it is overexpressed, which reflects a potential antiviral activity of this gene product under physiological conditions.
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Affiliation(s)
- Xusheng Qiu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Ifeanyichukwu E. Eke
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Silas F. Johnson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biology, Hillsdale College, Hillsdale, MI, 49242, USA
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Yong-Hui Zheng
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
- Corresponding author. (Y.-H. Zheng)
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31
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Featherstone A, Aiken C. SERINC5 Inhibits HIV-1 Infectivity by Altering the Conformation of gp120 on HIV-1 Particles. J Virol 2020; 94:e00594-20. [PMID: 32796070 PMCID: PMC7527050 DOI: 10.1128/jvi.00594-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/03/2020] [Indexed: 01/25/2023] Open
Abstract
SERINC5 is a 10-transmembrane-domain cellular protein that is incorporated into budding HIV-1 particles and reduces HIV-1 infectivity by inhibiting virus-cell fusion. HIV-1 susceptibility to SERINC5 is determined by sequences in the viral Env glycoprotein gp120, and the antiviral effect of SERINC5 is counteracted by the viral accessory protein Nef. While the precise mechanism by which SERINC5 inhibits HIV-1 infectivity is unclear, previous studies have suggested that SERINC5 affects Env conformation. To define the effects of SERINC5 on Env conformation, we quantified the binding of HIV-1 particles to immobilized Env-specific monoclonal antibodies. We observed that SERINC5 reduced the binding of HIV-1 particles bearing a SERINC5-susceptible Env to antibodies that recognize the V3 loop, a soluble CD4 (sCD4)-induced epitope, and an N-linked glycan. In contrast, SERINC5 did not alter the capture of HIV-1 particles bearing the SERINC5-resistant Env protein. Moreover, the effect of SERINC5 on antibody-dependent virus capture was abrogated by Nef expression. Our results indicate that SERINC5 inhibits HIV-1 infectivity by altering the conformation of gp120 on virions and/or physical masking of specific HIV-1 Env epitopes.IMPORTANCE SERINC5 is a host cell protein that inhibits the infectivity of HIV-1 by a novel and poorly understood mechanism. Here, we provide evidence that the SERINC5 protein alters the conformation of the HIV-1 Env proteins and that this action is correlated with SERINC5's ability to inhibit HIV-1 infectivity. Defining the specific effects of SERINC5 on the HIV-1 glycoprotein conformation may be useful for designing new antiviral strategies targeting Env.
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Affiliation(s)
- Austin Featherstone
- Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, Nashville, Tennessee, USA
| | - Christopher Aiken
- Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, Nashville, Tennessee, USA
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32
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Munis AM. Gene Therapy Applications of Non-Human Lentiviral Vectors. Viruses 2020; 12:v12101106. [PMID: 33003635 PMCID: PMC7599719 DOI: 10.3390/v12101106] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 12/14/2022] Open
Abstract
Recent commercialization of lentiviral vector (LV)-based cell therapies and successful reports of clinical studies have demonstrated the untapped potential of LVs to treat diseases and benefit patients. LVs hold notable and inherent advantages over other gene transfer agents based on their ability to transduce non-dividing cells, permanently transform target cell genome, and allow stable, long-term transgene expression. LV systems based on non-human lentiviruses are attractive alternatives to conventional HIV-1-based LVs due to their lack of pathogenicity in humans. This article reviews non-human lentiviruses and highlights their unique characteristics regarding virology and molecular biology. The LV systems developed based on these lentiviruses, as well as their successes and shortcomings, are also discussed. As the field of gene therapy is advancing rapidly, the use of LVs uncovers further challenges and possibilities. Advances in virology and an improved understanding of lentiviral biology will aid in the creation of recombinant viral vector variants suitable for translational applications from a variety of lentiviruses.
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Affiliation(s)
- Altar M Munis
- Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
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33
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Chen YC, Sood C, Marin M, Aaron J, Gratton E, Salaita K, Melikyan GB. Super-Resolution Fluorescence Imaging Reveals That Serine Incorporator Protein 5 Inhibits Human Immunodeficiency Virus Fusion by Disrupting Envelope Glycoprotein Clusters. ACS NANO 2020; 14:10929-10943. [PMID: 32441921 PMCID: PMC8274448 DOI: 10.1021/acsnano.0c02699] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Serine incorporator protein 5 (SERINC5) is the host antiretroviral factor that reduces HIV-1 infectivity by incorporating into virions and inhibiting the envelope glycoprotein (Env) mediated virus fusion with target cells. We and others have shown that SERINC5 incorporation into virions alters the Env structure and sensitizes the virus to broadly neutralizing antibodies targeting cryptic Env epitopes. We have also found that SERINC5 accelerates the loss of Env function over time compared to control viruses. However, the exact mechanism by which SERINC5 inhibits HIV-1 fusion is not understood. Here, we utilized 2D and 3D super-resolution microscopy to examine the effect of SERINC5 on the distribution of Env glycoproteins on single HIV-1 particles. We find that, in agreement with a previous report, Env glycoproteins form clusters on the surface of mature virions. Importantly, incorporation of SERINC5, but not SERINC2, which lacks antiviral activity, disrupted Env clusters without affecting the overall Env content. We also show that SERINC5 and SERINC2 also form clusters on single virions. Unexpectedly, Env and SERINC molecules exhibited poor codistribution on virions, as evidenced by much greater Env-SERINC pairwise distances compared to Env-Env distances. This observation is inconsistent with the previously reported interaction between Env and SERINC5 and suggests an indirect effect of SERINC5 on Env cluster formation. Collectively, our results reveal a multifaceted mechanism of SERINC5-mediated restriction of HIV-1 fusion that, aside from the effects on individual Env trimers, involves disruption of Env clusters, which likely serve as sites of viral fusion with target cells.
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Affiliation(s)
- Yen-Cheng Chen
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Chetan Sood
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Mariana Marin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jesse Aaron
- Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California Irvine, Irvine, CA 92617, USA
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Gregory B. Melikyan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
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34
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Proulx J, Borgmann K, Park IW. Post-translational modifications inducing proteasomal degradation to counter HIV-1 infection. Virus Res 2020; 289:198142. [PMID: 32882242 DOI: 10.1016/j.virusres.2020.198142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022]
Abstract
Post-translational modifications (PTMs) are integral to regulating a wide variety of cellular processes in eukaryotic cells, such as regulation of protein stability, alteration of celluar location, protein activity modulation, and regulation of protein interactions. HIV-1, like other eukaryotic viruses, and its infected host exploit the proteasomal degradation system for their respective proliferation and survival, using various PTMs, including but not limited to ubiquitination, SUMOylation, NEDDylation, interferon-stimulated gene (ISG)ylation. Essentially all viral proteins within the virions -- and in the HIV-1-infected cells -- interact with their cellular counterparts for this degradation, utilizing ubiquitin (Ub), and the Ub-like (Ubl) modifiers less frequently, to eliminate the involved proteins throughout the virus life cycle, from the entry step to release of the assembled virus particles. Such interplay is pivotal for, on the one hand, the cell to restrict proliferation of the infecting virus, and on the other, for molecular counteraction by the virus to overcome this cellular protein-imposed restriction. Recent reports indicate that not only viral/cellular proteins but also viral/viral protein interactions play vital roles in regulating viral protein stability. We hence give an overview of the molecular processes of PTMs involved in proteasomal degradation of the viral and cellular proteins, and the viral/viral and viral/cellular protein interplay in restriction and competition for HIV-1 vs. host cell survival. Insights in this realm could open new avenues for developing therapeutics against HIV-1 via targeting specific steps of the proteasome degradation pathway during the HIV-1 life cycle.
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Affiliation(s)
- Jessica Proulx
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Kathleen Borgmann
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - In-Woo Park
- Microbiology, Immunology, and Genetics, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States.
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35
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Li W, Zhang Z, Zhang L, Li H, Fan S, Zhu E, Fan J, Li Z, Chen W, Yi L, Ding H, Chen J, Zhao M. Antiviral Role of Serine Incorporator 5 (SERINC5) Proteins in Classical Swine Fever Virus Infection. Front Microbiol 2020; 11:580233. [PMID: 33013817 PMCID: PMC7498654 DOI: 10.3389/fmicb.2020.580233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 08/17/2020] [Indexed: 12/28/2022] Open
Abstract
Serine incorporator 5 (SERINC5), a multipass transmembrane protein, protects cells from viral infections. The mechanism by which SERINC5 protects against classical swine fever virus (CSFV) infection is unknown. In this study, overexpression of SERINC5 in PK-15 and 3D4/2 cells significantly inhibited the growth of CSFV, whereas SERINC5 silencing enhanced CSFV growth. Additionally, CSFV infection reduced SERINC5 production in cells and tissues. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify and analyze protein and peptide molecules that potentially interact with SERINC5. A total of 33 cellular protein candidates were identified. Next, SERINC5 was shown to interact with melanoma differentiation-associated protein 5 (MDA5) by yeast two-hybrid, protein co-localization and co-immunoprecipitation assays. Furthermore, SERINC5 enhanced MDA5-mediated type I interferon (IFN) signaling in a dose-dependent manner. Our results suggest that the anti-CSFV effect of SERINC5 is dependent on the activation of the type I IFN, which may function along with MDA5. The inhibitory effect of SERINC5 on CSFV was disappeared when the endogenous expression of MDA5 was silenced using siRNA, suggesting that SERINC5 exerts an anti-CSFV effect in an MDA5-dependent manner. Our study demonstrated a novel link between SERINC5 and MDA5 in the inhibition of CSFV replication via the type I IFN signaling pathway.
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Affiliation(s)
- Wenhui Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Zilin Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Liangliang Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Hong Li
- Shandong Qianxi Agriculture & Animal Husbandry Development Co., Ltd., Zaozhuang, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Erpeng Zhu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Jindai Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Zhaoyao Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Wenxian Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Lin Yi
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Hongxing Ding
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
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Abstract
This study examined for the first time the in vivo function of the serine incorporator (SERINC) proteins during retrovirus infection. SERINC3 and SERINC5 (SERINC3/5) restrict a number of retroviruses, including human immunodeficiency virus 1 (HIV-1) and murine leukemia virus (MLV), by blocking their entry into cells. Nevertheless, HIV-1 and MLV encode factors, Nef and glycosylated Gag, respectively, that counteract SERINC3/5 in vitro. We recently developed SERINC3 and SERINC5 knockout mice to examine the in vivo function of these genes. We found that SERINC5 restriction is dependent on the absence of glycosylated Gag and the expression of a specific viral envelope glycoprotein. On the other hand, SERINC3 had no antiviral function. Our findings have implications for the development of therapeutics that target SERINC5 during retrovirus infection. The serine incorporator (SERINC) proteins are multipass transmembrane proteins that affect sphingolipid and phosphatidylserine synthesis. Human SERINC5 and SERINC3 were recently shown to possess antiretroviral activity for a number of retroviruses, including human immunodeficiency virus (HIV), murine leukemia virus (MLV), and equine infectious anemia virus (EIAV). In the case of MLV, the glycosylated Gag (glyco-Gag) protein was shown to counteract SERINC5-mediated restriction in in vitro experiments and the viral envelope was found to determine virion sensitivity or resistance to SERINC5. However, nothing is known about the in vivo function of SERINC5. Antiretroviral function of a host factor in vitro is not always associated with antiretroviral function in vivo. Using SERINC5−/− mice that we had generated, we showed that mouse SERINC5 (mSERINC5) restriction of MLV infection in vivo is influenced not only by glyco-Gag but also by the retroviral envelope. Finally, we also examined the in vivo function of the other SERINC gene with known antiretroviral functions, SERINC3. By using SERINC3−/− mice, we found that the murine homologue, mSERINC3, had no antiretroviral role either in vivo or in vitro. To our knowledge, this report provides the first data showing that SERINC5 restricts retrovirus infection in vivo and that restriction of retrovirus infectivity in vivo is dependent on the presence of both glyco-Gag and the viral envelope.
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37
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Hussain MW, Bhardwaj V, Giri A, Chande A, Patra A. Multifunctional ionic porous frameworks for CO 2 conversion and combating microbes. Chem Sci 2020; 11:7910-7920. [PMID: 34123075 PMCID: PMC8163429 DOI: 10.1039/d0sc01658f] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 07/01/2020] [Indexed: 01/14/2023] Open
Abstract
Porous organic frameworks (POFs) with a heteroatom rich ionic backbone have emerged as advanced materials for catalysis, molecular separation, and antimicrobial applications. The loading of metal ions further enhances Lewis acidity, augmenting the activity associated with such frameworks. Metal-loaded ionic POFs, however, often suffer from physicochemical instability, thereby limiting their scope for diverse applications. Herein, we report the fabrication of triaminoguanidinium-based ionic POFs through Schiff base condensation in a cost-effective and scalable manner. The resultant N-rich ionic frameworks facilitate selective CO2 uptake and afford high metal (Zn(ii): 47.2%) loading capacity. Owing to the ionic guanidinium core and ZnO infused mesoporous frameworks, Zn/POFs showed pronounced catalytic activity in the cycloaddition of CO2 and epoxides into cyclic organic carbonates under solvent-free conditions with high catalyst recyclability. The synergistic effect of infused ZnO and cationic triaminoguanidinium frameworks in Zn/POFs led to robust antibacterial (Gram-positive, Staphylococcus aureus and Gram-negative, Escherichia coli) and antiviral activity targeting HIV-1 and VSV-G enveloped lentiviral particles. We thus present triaminoguanidinium-based POFs and Zn/POFs as a new class of multifunctional materials for environmental remediation and biomedical applications.
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Affiliation(s)
- Md Waseem Hussain
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 Madhya Pradesh India
| | - Vipin Bhardwaj
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 Madhya Pradesh India
| | - Arkaprabha Giri
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 Madhya Pradesh India
| | - Ajit Chande
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 Madhya Pradesh India
| | - Abhijit Patra
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 Madhya Pradesh India
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38
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Thippeshappa R, Kimata JT, Kaushal D. Toward a Macaque Model of HIV-1 Infection: Roadblocks, Progress, and Future Strategies. Front Microbiol 2020; 11:882. [PMID: 32477302 PMCID: PMC7237640 DOI: 10.3389/fmicb.2020.00882] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022] Open
Abstract
The human-specific tropism of Human Immunodeficiency Virus Type 1 (HIV-1) has complicated the development of a macaque model of HIV-1 infection/AIDS that is suitable for preclinical evaluation of vaccines and novel treatment strategies. Several innate retroviral restriction factors, such as APOBEC3 family of proteins, TRIM5α, BST2, and SAMHD1, that prevent HIV-1 replication have been identified in macaque cells. Accessory proteins expressed by Simian Immunodeficiency virus (SIV) such as viral infectivity factor (Vif), viral protein X (Vpx), viral protein R (Vpr), and negative factor (Nef) have been shown to play key roles in overcoming these restriction factors in macaque cells. Thus, substituting HIV-1 accessory genes with those from SIV may enable HIV-1 replication in macaques. We and others have constructed macaque-tropic HIV-1 derivatives [also called simian-tropic HIV-1 (stHIV-1) or Human-Simian Immunodeficiency Virus (HSIV)] carrying SIV vif to overcome APOBEC3 family proteins. Additional modifications to HIV-1 gag in some of the macaque-tropic HIV-1 have also been done to overcome TRIM5α restriction in rhesus and cynomolgus macaques. Although these viruses replicate persistently in macaque species, they do not result in CD4 depletion. Thus, these studies suggest that additional blocks to HIV-1 replication exist in macaques that prevent high-level viral replication. Furthermore, serial animal-to-animal passaging of macaque-tropic HIV-1 in vivo has not resulted in pathogenic variants that cause AIDS in immunocompetent macaques. In this review, we discuss recent developments made toward developing macaque model of HIV-1 infection.
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Affiliation(s)
- Rajesh Thippeshappa
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Jason T Kimata
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Deepak Kaushal
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
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Liu Y, Wang H, Zhang J, Yang J, Bai L, Zheng B, Zheng T, Wang Y, Li J, Zhang W. SERINC5 Inhibits the Secretion of Complete and Genome-Free Hepatitis B Virions Through Interfering With the Glycosylation of the HBV Envelope. Front Microbiol 2020; 11:697. [PMID: 32431673 PMCID: PMC7216740 DOI: 10.3389/fmicb.2020.00697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/25/2020] [Indexed: 12/22/2022] Open
Abstract
Serine incorporator 3 (SERINC3) and SERINC5 were recently identified as host intrinsic factors against human immunodeficiency virus (HIV)-1 and counteracted by HIV-1 Nef. However, whether they inhibit hepatitis B virus (HBV), which is a severe health problem worldwide, is unknown. Here, we demonstrate that SERINC5 potently inhibited HBV virion secretion in the supernatant without affecting intracellular core particle-associated DNA and the total RNA, but SERINC3 and SERINC1 did not. Further investigation discovered that SERINC5 increased the non-glycosylation of LHB, MHB, and SHB proteins of HBV and slightly decreased HBs proteins levels, which led to the decreased HBV secretion. Importantly, SERINC5 co-localized with LHB proteins in the Golgi apparatus, which is important for glycan processing and transport. In addition, we determined the functional domain in SERINC5 required for HBV inhibition, which was completely different from that required for HIV-1 restriction, whereas phosphorylation and glycosylation sites in SERINC5 were dispensable for HBV restriction. Taken together, our results demonstrate that SERINC5 suppresses HBV virion secretion through interfering with the glycosylation of HBV proteins, suggesting that SERINC5 might possess broad-spectrum antiviral activity.
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Affiliation(s)
- Yue Liu
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China.,Department of Echocardiography, The First Hospital of Jilin University, Changchun, China
| | - Hong Wang
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Jun Zhang
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Jing Yang
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Lu Bai
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Baisong Zheng
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Tianhang Zheng
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Yingchao Wang
- Department of Hepatobiliary Pancreatic Surgery, The First Hospital of Jilin University, Changchun, China
| | - Jianhua Li
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Wenyan Zhang
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
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40
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Stoneham CA, Ramirez PW, Singh R, Suarez M, Debray A, Lim C, Jia X, Xiong Y, Guatelli J. A Conserved Acidic-Cluster Motif in SERINC5 Confers Partial Resistance to Antagonism by HIV-1 Nef. J Virol 2020; 94:e01554-19. [PMID: 31941773 PMCID: PMC7081897 DOI: 10.1128/jvi.01554-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/12/2020] [Indexed: 12/15/2022] Open
Abstract
The cellular protein SERINC5 inhibits the infectivity of diverse retroviruses, and its activity is counteracted by the glycosylated Gag (glycoGag) protein of murine leukemia virus (MLV), the S2 protein of equine infectious anemia virus (EIAV), and the Nef protein of human immunodeficiency virus type 1 (HIV-1). Determining the regions within SERINC5 that provide restrictive activity or Nef sensitivity should inform mechanistic models of the SERINC5/HIV-1 relationship. Here, we report that deletion of the conserved sequence EDTEE, which is located within a cytoplasmic loop of SERINC5 and which is reminiscent of an acidic-cluster membrane trafficking signal, increases the sensitivity of SERINC5 to antagonism by Nef, while it has no effect on the intrinsic activity of the protein as an inhibitor of infectivity. These effects correlated with enhanced removal of the ΔEDTEE mutant relative to that of wild-type SERINC5 from the cell surface and with enhanced exclusion of the mutant protein from virions by Nef. Mutational analysis indicated that the acidic residues, but not the threonine, within the EDTEE motif are important for the relative resistance to Nef. Deletion of the EDTEE sequence did not increase the sensitivity of SERINC5 to antagonism by the glycoGag protein of MLV, suggesting that its virologic role is Nef specific. These results are consistent with the reported mapping of the cytoplasmic loop that contains the EDTEE sequence as a general determinant of Nef responsiveness, but they further indicate that sequences inhibitory to as well as supportive of Nef activity reside in this region. We speculate that the EDTEE motif might have evolved to mediate resistance against retroviruses that use Nef-like proteins to antagonize SERINC5.IMPORTANCE Cellular membrane proteins in the SERINC family, especially SERINC5, inhibit the infectivity of retroviral virions. This inhibition is counteracted by retroviral proteins, specifically, HIV-1 Nef, MLV glycoGag, and EIAV S2. One consequence of such a host-pathogen "arms race" is a compensatory change in the host antiviral protein as it evolves to escape the effects of viral antagonists. This is often reflected in a genetic signature, positive selection, which is conspicuously missing in SERINC5 Here we show that despite this lack of genetic evidence, a sequence in SERINC5 nonetheless provides relative resistance to antagonism by HIV-1 Nef.
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Affiliation(s)
- Charlotte A Stoneham
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- The VA San Diego Healthcare System, San Diego, California, USA
| | - Peter W Ramirez
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Rajendra Singh
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- The VA San Diego Healthcare System, San Diego, California, USA
| | - Marissa Suarez
- The VA San Diego Healthcare System, San Diego, California, USA
| | - Andrew Debray
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Christopher Lim
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Xiaofei Jia
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, Dartmouth, Massachusetts, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - John Guatelli
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- The VA San Diego Healthcare System, San Diego, California, USA
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41
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Abstract
Interferon-induced transmembrane (IFITM) proteins are encoded by many vertebrate species and exhibit antiviral activities against a wide range of viruses. IFITM3, when present in virus-producing cells, reduces the fusion potential of HIV-1 virions, but the mechanism is poorly understood. To define the breadth and mechanistic basis for the antiviral activity of IFITM3, we took advantage of a murine leukemia virus (MLV)-based pseudotyping system. By carefully controlling amounts of IFITM3 and envelope protein (Env) in virus-producing cells, we found that IFITM3 potently inhibits MLV infectivity when Env levels are limiting. Loss of infectivity was associated with defective proteolytic processing of Env and lysosomal degradation of the Env precursor. Ecotropic and xenotropic variants of MLV Env, as well as HIV-1 Env and vesicular stomatitis virus glycoprotein (VSV-G), are sensitive to IFITM3, whereas Ebola glycoprotein is resistant, suggesting that IFITM3 selectively inactivates certain viral glycoproteins. Furthermore, endogenous IFITM3 in human and murine cells negatively regulates MLV Env abundance. However, we found that the negative impact of IFITM3 on virion infectivity is greater than its impact on decreasing Env incorporation, suggesting that IFITM3 may impair Env function, as well as reduce the amount of Env in virions. Finally, we demonstrate that loss of virion infectivity mediated by IFITM3 is reversed by the expression of glycoGag, a murine retrovirus accessory protein previously shown to antagonize the antiviral activity of SERINC proteins. Overall, we show that IFITM3 impairs virion infectivity by regulating Env quantity and function but that enhanced Env expression and glycoGag confer viral resistance to IFITM3.IMPORTANCE The viral envelope glycoprotein, known as "Env" in Retroviridae, is found on the virion surface and facilitates virus entry into cells by mediating cell attachment and fusion. Env is a major structural component of retroviruses and is targeted by all arms of the immune response, including adaptive and innate immunity. Less is known about how cell-intrinsic immunity prevents retrovirus replication at the level of individual cells. Here, we show that cellular IFITM3 and IFITM2 inhibit the fusion potential of retroviral virions by inhibiting Env protein via a two-pronged mechanism. IFITM proteins inhibit Env abundance in cells and also impair its function when levels are low. The posttranslational block of retroviral Env function by IFITM proteins is likely to impede both exogenous and endogenous retrovirus replication. In support of a relevant role for IFITM3 in retrovirus control, the retroviral accessory protein glycoGag counteracts IFITM3 function to promote virus infectivity.
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42
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Pye VE, Rosa A, Bertelli C, Struwe WB, Maslen SL, Corey R, Liko I, Hassall M, Mattiuzzo G, Ballandras-Colas A, Nans A, Takeuchi Y, Stansfeld PJ, Skehel JM, Robinson CV, Pizzato M, Cherepanov P. A bipartite structural organization defines the SERINC family of HIV-1 restriction factors. Nat Struct Mol Biol 2020; 27:78-83. [PMID: 31907454 PMCID: PMC6956856 DOI: 10.1038/s41594-019-0357-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/26/2019] [Indexed: 12/14/2022]
Abstract
The human integral membrane protein SERINC5 potently restricts HIV-1 infectivity and sensitizes the virus to antibody-mediated neutralization. Here, using cryo-EM, we determine the structures of human SERINC5 and its orthologue from Drosophila melanogaster at subnanometer and near-atomic resolution, respectively. The structures reveal a novel fold comprised of ten transmembrane helices organized into two subdomains and bisected by a long diagonal helix. A lipid binding groove and clusters of conserved residues highlight potential functional sites. A structure-based mutagenesis scan identified surface-exposed regions and the interface between the subdomains of SERINC5 as critical for HIV-1-restriction activity. The same regions are also important for viral sensitization to neutralizing antibodies, directly linking the antiviral activity of SERINC5 with remodeling of the HIV-1 envelope glycoprotein.
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Affiliation(s)
- Valerie E Pye
- Chromatin Structure and Mobile DNA Laboratory, Francis Crick Institute, London, UK
| | - Annachiara Rosa
- Chromatin Structure and Mobile DNA Laboratory, Francis Crick Institute, London, UK
| | - Cinzia Bertelli
- Department of Cellular, Computational and Integrative Biology, University of Trento, Povo, Italy
| | - Weston B Struwe
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
| | - Sarah L Maslen
- Biological Mass Spectrometry and Proteomics Laboratory, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Robin Corey
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Idlir Liko
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
| | - Mark Hassall
- National Institute for Biological Standards and Control, Hertfordshire, UK
| | - Giada Mattiuzzo
- National Institute for Biological Standards and Control, Hertfordshire, UK
| | | | - Andrea Nans
- Structural Biology Science Technology Platform, Francis Crick Institute, London, UK
| | - Yasuhiro Takeuchi
- National Institute for Biological Standards and Control, Hertfordshire, UK
- UCL Division of Infection and Immunity, The Rayne Building, London, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences & Department of Chemistry, University of Warwick, Warwick, UK
| | - J Mark Skehel
- Biological Mass Spectrometry and Proteomics Laboratory, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
| | - Massimo Pizzato
- Department of Cellular, Computational and Integrative Biology, University of Trento, Povo, Italy.
| | - Peter Cherepanov
- Chromatin Structure and Mobile DNA Laboratory, Francis Crick Institute, London, UK.
- Department of Infectious Disease, Imperial College London, St Mary's Campus, Norfolk Place, London, UK.
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43
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Characterization of Endogenous SERINC5 Protein as Anti-HIV-1 Factor. J Virol 2019; 93:JVI.01221-19. [PMID: 31597782 PMCID: PMC6880170 DOI: 10.1128/jvi.01221-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/24/2019] [Indexed: 01/07/2023] Open
Abstract
SERINC5 is the long-searched-for antiviral factor that is counteracted by the HIV-1 accessory gene product Nef. Here, we engineered, via CRISPR/Cas9 technology, T-cell lines that express endogenous SERINC5 alleles tagged with a knocked-in HA epitope. This genetic modification enabled us to study basic properties of endogenous SERINC5 and to verify proposed mechanisms of HIV-1 Nef-mediated counteraction of SERINC5. Using this unique resource, we identified the susceptibility of endogenous SERINC5 protein to posttranslational modulation by type I IFNs and suggest uncoupling of Nef-mediated functional antagonism from SERINC5 exclusion from virions. When expressed in virus-producing cells, the cellular multipass transmembrane protein SERINC5 reduces the infectivity of HIV-1 particles and is counteracted by HIV-1 Nef. Due to the unavailability of an antibody of sufficient specificity and sensitivity, investigation of SERINC5 protein expression and subcellular localization has been limited to heterologously expressed SERINC5. We generated, via CRISPR/Cas9-assisted gene editing, Jurkat T-cell clones expressing endogenous SERINC5 bearing an extracellularly exposed hemagglutinin (HA) epitope [Jurkat SERINC5(iHA knock-in) T cells]. This modification enabled quantification of endogenous SERINC5 protein levels and demonstrated a predominant localization in lipid rafts. Interferon alpha (IFN-α) treatment enhanced cell surface levels of SERINC5 in a ruxolitinib-sensitive manner in the absence of modulation of mRNA and protein quantities. Parental and SERINC5(iHA knock-in) T cells shared the ability to produce infectious wild-type HIV-1 but not an HIV-1 Δnef mutant. SERINC5-imposed reduction of infectivity involved a modest reduction of virus fusogenicity. An association of endogenous SERINC5 protein with HIV-1 Δnef virions was consistently detectable as a 35-kDa species, as opposed to heterologous SERINC5, which presented as a 51-kDa species. Nef-mediated functional counteraction did not correlate with virion exclusion of SERINC5, arguing for the existence of additional counteractive mechanisms of Nef that act on virus-associated SERINC5. In HIV-1-infected cells, Nef triggered the internalization of SERINC5 in the absence of detectable changes of steady-state protein levels. These findings establish new properties of endogenous SERINC5 expression and subcellular localization, challenge existing concepts of HIV-1 Nef-mediated antagonism of SERINC5, and uncover an unprecedented role of IFN-α in modulating SERINC5 through accumulation at the cell surface. IMPORTANCE SERINC5 is the long-searched-for antiviral factor that is counteracted by the HIV-1 accessory gene product Nef. Here, we engineered, via CRISPR/Cas9 technology, T-cell lines that express endogenous SERINC5 alleles tagged with a knocked-in HA epitope. This genetic modification enabled us to study basic properties of endogenous SERINC5 and to verify proposed mechanisms of HIV-1 Nef-mediated counteraction of SERINC5. Using this unique resource, we identified the susceptibility of endogenous SERINC5 protein to posttranslational modulation by type I IFNs and suggest uncoupling of Nef-mediated functional antagonism from SERINC5 exclusion from virions.
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Cook SJ, Li G, Zheng Y, Willand ZA, Issel CJ, Cook RF. Molecular Characterization of the Major Open Reading Frames (ORFs) and Enhancer Elements From Four Geographically Distinct North American Equine Infectious Anemia Virus (EIAV) Isolates. J Equine Vet Sci 2019; 85:102852. [PMID: 31952638 DOI: 10.1016/j.jevs.2019.102852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/01/2019] [Accepted: 11/08/2019] [Indexed: 02/05/2023]
Abstract
Although the equine lentivirus (equine infectious anemia virus [EIAV]) poses a major threat to equid populations throughout most regions of the world, detailed knowledge concerning its molecular epidemiology is still in its infancy. Such information is important because the few studies conducted to date suggest there is extensive genetic variation between viral isolates that if confirmed has significant implications for future vaccine design and development of newer diagnostic procedures. Here, we avoid potential assembly artifacts inherent in composite sequencing techniques by using long-range PCR in conjunction with next-generation sequencing for the rapid molecular characterization of all major open reading frames (ORFs) and known transcription factor binding motifs within the long terminal repeats (LTRs) of four North American EIAV isolates from Pennsylvania (EIAVPA), Tennessee (EIAVTN), North Carolina (EIAVNC), and Florida (EIAVFL). These were compared with complete published EIAV field strain genomic sequences from Asia (EIAVLIA, EIAVMIY), Europe (EIAVIRE), and North America (EIAVWY) plus EIAVUK a laboratory variant of EIAVWY. Phylogenetic analysis using the long-range PCR products suggested all the New World EIAV isolates comprised a single monophyletic group associated with EIAVIRE. This is distinct from the Asian isolates and so consistent with known historical details concerning the reintroduction of equids into North America by European settlers. Nonetheless nucleotide sequence identity for example between EIAVPA and EIAVTN, EIAVNC, EIAVFL, EIAVWY, EIAVUK plus EIAVIRE was limited to 84.6%, 81.0%, 82.1%, 80.4%, 80.1%, and 77.6%, respectively, with some of these values being not too dissimilar to those between EIAVPA and EIAVLIA or EIAVMIY at 78.0% and 75.4%, respectively. Overall, these results suggest substantial genetic diversity exists even within North American EIAV isolates. Comparative alignment of predicted amino acid sequences from all strains provides increased understanding concerning the extent of permitted substitutions in each viral ORF and known transcriptional LTR control elements.
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Affiliation(s)
- Sheila J Cook
- Department of Veterinary Science, Maxwell-Gluck Equine Research Center, University of Kentucky, Lexington, KY
| | - Ganwu Li
- NGS Unit, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA
| | - Ying Zheng
- NGS Unit, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA
| | - Zachary A Willand
- Department of Veterinary Science, Maxwell-Gluck Equine Research Center, University of Kentucky, Lexington, KY
| | - Charles J Issel
- Department of Veterinary Science, Maxwell-Gluck Equine Research Center, University of Kentucky, Lexington, KY
| | - R Frank Cook
- Department of Veterinary Science, Maxwell-Gluck Equine Research Center, University of Kentucky, Lexington, KY.
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Evans JP, Liu SL. Multifaceted Roles of TIM-Family Proteins in Virus-Host Interactions. Trends Microbiol 2019; 28:224-235. [PMID: 31732320 DOI: 10.1016/j.tim.2019.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/25/2019] [Accepted: 10/10/2019] [Indexed: 01/16/2023]
Abstract
To enhance infection, enveloped viruses exploit adhesion molecules expressed on the surface of host cells. Specifically, phosphatidylserine (PS) receptors - including members of the human T cell immunoglobulin and mucin domain (TIM)-family - have gained attention for their ability to mediate the entry of many enveloped viruses. However, recent evidence that TIM-1 can restrict viral release reveals a new role for these PS receptors. Additionally, viral factors such as the HIV-1 accessory protein Nef can antagonize this antiviral activity of TIM-1 while host restriction factors such as SERINC5 can enhance it. In this review, we examine the various roles of PS receptors, specifically TIM-family proteins, and the intricate relationship between host and viral factors. Elucidating the multifunctional roles of PS receptors in virus-host interaction is important for understanding viral pathogenesis and developing novel antiviral therapeutics.
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Affiliation(s)
- John P Evans
- Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA; Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Shan-Lu Liu
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA; Viruses and Emerging Pathogens Program, Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA.
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Vpr and Its Cellular Interaction Partners: R We There Yet? Cells 2019; 8:cells8111310. [PMID: 31652959 PMCID: PMC6912716 DOI: 10.3390/cells8111310] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/17/2022] Open
Abstract
Vpr is a lentiviral accessory protein that is expressed late during the infection cycle and is packaged in significant quantities into virus particles through a specific interaction with the P6 domain of the viral Gag precursor. Characterization of the physiologically relevant function(s) of Vpr has been hampered by the fact that in many cell lines, deletion of Vpr does not significantly affect viral fitness. However, Vpr is critical for virus replication in primary macrophages and for viral pathogenesis in vivo. It is generally accepted that Vpr does not have a specific enzymatic activity but functions as a molecular adapter to modulate viral or cellular processes for the benefit of the virus. Indeed, many Vpr interacting factors have been described by now, and the goal of this review is to summarize our current knowledge of cellular proteins targeted by Vpr.
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Ramirez PW, Sharma S, Singh R, Stoneham CA, Vollbrecht T, Guatelli J. Plasma Membrane-Associated Restriction Factors and Their Counteraction by HIV-1 Accessory Proteins. Cells 2019; 8:E1020. [PMID: 31480747 PMCID: PMC6770538 DOI: 10.3390/cells8091020] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 02/07/2023] Open
Abstract
The plasma membrane is a site of conflict between host defenses and many viruses. One aspect of this conflict is the host's attempt to eliminate infected cells using innate and adaptive cell-mediated immune mechanisms that recognize features of the plasma membrane characteristic of viral infection. Another is the expression of plasma membrane-associated proteins, so-called restriction factors, which inhibit enveloped virions directly. HIV-1 encodes two countermeasures to these host defenses: The membrane-associated accessory proteins Vpu and Nef. In addition to inhibiting cell-mediated immune-surveillance, Vpu and Nef counteract membrane-associated restriction factors. These include BST-2, which traps newly formed virions at the plasma membrane unless counteracted by Vpu, and SERINC5, which decreases the infectivity of virions unless counteracted by Nef. Here we review key features of these two antiviral proteins, and we review Vpu and Nef, which deplete them from the plasma membrane by co-opting specific cellular proteins and pathways of membrane trafficking and protein-degradation. We also discuss other plasma membrane proteins modulated by HIV-1, particularly CD4, which, if not opposed in infected cells by Vpu and Nef, inhibits viral infectivity and increases the sensitivity of the viral envelope glycoprotein to host immunity.
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Affiliation(s)
- Peter W Ramirez
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Shilpi Sharma
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Rajendra Singh
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Charlotte A Stoneham
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Thomas Vollbrecht
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - John Guatelli
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
- VA San Diego Healthcare System, San Diego, CA 92161, USA.
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Deshiere A, Berthet N, Lecouturier F, Gaudaire D, Hans A. Molecular characterization of Equine Infectious Anemia Viruses using targeted sequence enrichment and next generation sequencing. Virology 2019; 537:121-129. [PMID: 31493650 DOI: 10.1016/j.virol.2019.08.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 12/19/2022]
Abstract
Equine infectious anemia virus (EIAV) is responsible of acute disease episodes characterized by fever, anemia, thrombocytopenia and anorexia in equids. The high mutation rate in EIAV genome limited the number of full genome sequences availability. In the present study, we used the SureSelect target enrichment system with Illumina Next Generation Sequencing to characterize the proviral DNA of Equine Infectious Anemia Virus (EIAV) from asymptomatic horses. This approach allows a direct sequencing of the EIAV whole genome without cloning or amplification steps and we could obtain for the first time the complete genomic DNA sequences of French EIAV strains. We analyzed their phylogenetic relationship and genetic variability by comparison with 17 whole EIAV genome sequences from different parts of the world. The results obtained provide new insights into the molecular detection of EIAV and genetic diversity of European viral strains.
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Affiliation(s)
- Alexandre Deshiere
- ANSES- Laboratory for Animal Health in Normandy, Physiopathology and Epidemiology of Equine Diseases Unit, Goustranville, France
| | - Nicolas Berthet
- Institut Pasteur, Unité Environnement et Risques Infectieux, Cellule d'Intervention Biologique d'Urgence, Paris, France; Centre National de Recherche Scientifique (CNRS) UMR3569, Paris, France
| | - Fanny Lecouturier
- ANSES- Laboratory for Animal Health in Normandy, Physiopathology and Epidemiology of Equine Diseases Unit, Goustranville, France
| | - Delphine Gaudaire
- ANSES- Laboratory for Animal Health in Normandy, Physiopathology and Epidemiology of Equine Diseases Unit, Goustranville, France
| | - Aymeric Hans
- ANSES- Laboratory for Animal Health in Normandy, Physiopathology and Epidemiology of Equine Diseases Unit, Goustranville, France.
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CD4 Expression and Env Conformation Are Critical for HIV-1 Restriction by SERINC5. J Virol 2019; 93:JVI.00544-19. [PMID: 31043528 DOI: 10.1128/jvi.00544-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/25/2019] [Indexed: 12/29/2022] Open
Abstract
Serine incorporator 5 (SERINC5) is a recently identified restriction factor that strongly blocks HIV-1 entry but is counteracted by Nef. Notably, tier 1 HIV-1 Env proteins are sensitive to SERINC5, whereas the majority of tier 2/3 Env proteins are resistant to SERINC5, when viruses are produced from CD4-negative cells and tested by a single-round replication assay. Here, we investigated the Env-dependent SERINC5 antiviral mechanism by comparing tier 1 NL Env with tier 3 AD8 Env proteins. We found that when NL and AD8 viruses were inoculated into CD4+ T cells and human peripheral blood mononuclear cells (PBMCs), the propagation of the two viruses was restricted to a similar level when Nef was not expressed. Using a bimolecular fluorescence complementation (BiFC) assay, we detected Env-Env association and Env-SERINC5 interactions. A much greater level of NL Env-SERINC5 interactions was detected than was AD8 Env-SERINC5 interactions, which was further validated by immunoprecipitation assays. In addition, SERINC5 dissociated the NL Env trimeric complex more effectively than the AD8 Env trimeric complex when CD4 was not expressed. However, when CD4 was expressed, SERINC5 became more capable of interacting with AD8 Env and dissociating its trimeric complex. Moreover, AD8 and several other tier 2/3 viruses produced in the presence of CD4 became sensitive to SERINC5 when measured by the single-round replication assay. Because tier 1 and tier 2/3 Env trimers have open and closed conformations, respectively, and CD4 opens the closed conformation, we conclude that SERINC5 selectively dissociates Env trimers with an open conformation to restrict HIV-1 replication.IMPORTANCE Restriction factors provide the first line of defense against retrovirus infection by posing several blocks to the viral replication cycle. SERINC5 is a novel restriction factor that strongly blocks HIV-1 entry, although it is counteracted by Nef. Currently, it is still unclear how HIV-1 entry is blocked by SERINC5. Notably, this entry block is dependent on viral Env proteins. Laboratory-adapted HIV-1 strains are sensitive, whereas primary isolates are highly resistant to SERINC5. Env proteins mediate virus entry via extensive conformational rearrangements from a closed ground state to a CD4-bound open state. We detected Env-Env associations and Env-SERINC5 interactions in live cells by a novel bimolecular fluorescence assay. We demonstrate that CD4 expression increases the Env sensitivity to SERINC5 and allows SERINC5 to dissociate the Env complex, suggesting that SERINC5 restriction is dependent on Env conformation. Our results provide new insights into the poorly defined Env-dependent SERINC5 antiviral mechanism.
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Rojas VK, Park IW. Role of the Ubiquitin Proteasome System (UPS) in the HIV-1 Life Cycle. Int J Mol Sci 2019; 20:ijms20122984. [PMID: 31248071 PMCID: PMC6628307 DOI: 10.3390/ijms20122984] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 01/18/2023] Open
Abstract
Given that the ubiquitin proteasome system (UPS) is the major protein degradation process in the regulation of a wide variety of cellular processes in eukaryotic cells, including alteration of cellular location, modulation of protein activity, and regulation of protein interaction, it is reasonable to suggest that the infecting HIV-1 and the invaded hosts exploit the UPS in a contest for survival and proliferation. However, to date, regulation of the HIV-1 life cycle has been mainly explained by the stage-specific expression of HIV-1 viral genes, not by elimination processes of the synthesized proteins after completion of their duties in the infected cells, which is also quintessential for understanding the molecular processes of the virus life cycle and thereby HIV-1 pathogenesis. In fact, several previous publications have indicated that the UPS plays a critical role in the regulation of the proteasomal degradation of viral and cellular counterparts at every step of the HIV-1 life cycle, from the virus entry to release of the assembled virus particles, which is integral for the regulation of survival and proliferation of the infecting HIV-1 and to replication restriction of the invading virus in the host. However, it is unknown whether and how these individual events taking place at different stages of the HIV-1 life cycle are orchestrated as an overall strategy to overcome the restrictions conferred by the host cells. Thus, in this review, we overview the interplay between HIV-1 viral and cellular proteins for restrictions/competitions for proliferation of the virus in the infected cell, which could open a new avenue for the development of therapeutics against HIV-1 via targeting a specific step of the proteasome degradation pathway during the HIV-1 life cycle.
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Affiliation(s)
- Vivian K Rojas
- Department of Microbiology, Immunology, and Genetics, University of North Texas, Health Science Center, Fort Worth, TX 76107, USA.
| | - In-Woo Park
- Department of Microbiology, Immunology, and Genetics, University of North Texas, Health Science Center, Fort Worth, TX 76107, USA.
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