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Raghunath G, Abbott EH, Marin M, Wu H, Reyes Ballista JM, Brindley MA, Melikyan GB. Disruption of Transmembrane Phosphatidylserine Asymmetry by HIV-1 Incorporated SERINC5 Is Not Responsible for Virus Restriction. Biomolecules 2024; 14:570. [PMID: 38785977 PMCID: PMC11118262 DOI: 10.3390/biom14050570] [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: 03/22/2024] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
Host restriction factor SERINC5 (SER5) incorporates into the HIV-1 membrane and inhibits infectivity by a poorly understood mechanism. Recently, SER5 was found to exhibit scramblase-like activity leading to the externalization of phosphatidylserine (PS) on the viral surface, which has been proposed to be responsible for SER5's antiviral activity. This and other reports that document modulation of HIV-1 infectivity by viral lipid composition prompted us to investigate the role of PS in regulating SER5-mediated HIV-1 restriction. First, we show that the level of SER5 incorporation into virions correlates with an increase in PS levels in the outer leaflet of the viral membrane. We developed an assay to estimate the PS distribution across the viral membrane and found that SER5, but not SER2, which lacks antiviral activity, abrogates PS asymmetry by externalizing this lipid. Second, SER5 incorporation diminished the infectivity of pseudoviruses produced from cells lacking a flippase subunit CDC50a and, therefore, exhibited a higher baseline level of surface-accessible PS. Finally, exogenous manipulation of the viral PS levels utilizing methyl-alpha-cyclodextrin revealed a lack of correlation between external PS and virion infectivity. Taken together, our study implies that the increased PS exposure to SER5-containing virions itself is not directly linked to HIV-1 restriction.
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Affiliation(s)
- Gokul Raghunath
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Elizabeth H. Abbott
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA
| | - Mariana Marin
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Hui Wu
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (M.M.); (H.W.)
| | - Judith Mary Reyes Ballista
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (J.M.R.B.); (M.A.B.)
| | - Melinda A. Brindley
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (J.M.R.B.); (M.A.B.)
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Gregory B. Melikyan
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
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2
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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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3
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Nkuwi E, Judicate GP, Tan TS, Barabona G, Toyoda M, Sunguya B, Kamori D, Ueno T. Relative resistance of patient-derived envelope sequences to SERINC5-mediated restriction of HIV-1 infectivity. J Virol 2023; 97:e0082323. [PMID: 37768085 PMCID: PMC10617508 DOI: 10.1128/jvi.00823-23] [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: 06/13/2023] [Accepted: 08/13/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE Pathogenesis of HIV-1 is enhanced through several viral-encoded proteins that counteract a range of host restriction molecules. HIV-1 Nef counteracts the cell membrane protein SERINC5 by downregulating it from the cell surface, thereby enhancing virion infectivity. Some subtype B reference Envelope sequences have shown the ability to bypass SERINC5 infectivity restriction independent of Nef. However, it is not clear if and to what extent circulating HIV-1 strains can exhibit resistance to SERINC5 restriction. Using a panel of Envelope sequences isolated from 50 Tanzanians infected with non-B HIV-1 subtypes, we show that the lentiviral reporters pseudotyped with patient-derived Envelopes have reduced sensitivity to SERINC5 and that this sensitivity differed among viral subtypes. Moreover, we found that SERINC5 sensitivity within patient-derived Envelopes can be modulated by separate regions, highlighting the complexity of viral/host interactions.
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Affiliation(s)
- Emmanuel Nkuwi
- Division of Infection and Immunity, Joint Research Center for Human Retrovirus Infection Kumamoto University, Kumamoto, Japan
- Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Department of Microbiology and Parasitology, The University of Dodoma, Dodoma, Tanzania
| | - George P. Judicate
- Division of Infection and Immunity, Joint Research Center for Human Retrovirus Infection Kumamoto University, Kumamoto, Japan
| | - Toong Seng Tan
- Division of Infection and Immunity, Joint Research Center for Human Retrovirus Infection Kumamoto University, Kumamoto, Japan
| | - Godfrey Barabona
- Division of Infection and Immunity, Joint Research Center for Human Retrovirus Infection Kumamoto University, Kumamoto, Japan
| | - Mako Toyoda
- Division of Infection and Immunity, Joint Research Center for Human Retrovirus Infection Kumamoto University, Kumamoto, Japan
| | - Bruno Sunguya
- Collaboration Unit for Infection, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
- Department of Community Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Doreen Kamori
- Collaboration Unit for Infection, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Takamasa Ueno
- Division of Infection and Immunity, Joint Research Center for Human Retrovirus Infection Kumamoto University, Kumamoto, Japan
- Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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4
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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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5
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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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6
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Cano-Ortiz L, Luedde T, Münk C. HIV-1 restriction by SERINC5. Med Microbiol Immunol 2023; 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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Raghunath G, Chen YC, Marin M, Wu H, Melikyan GB. SERINC5-Mediated Restriction of HIV-1 Infectivity Correlates with Resistance to Cholesterol Extraction but Not with Lipid Order of Viral Membrane. Viruses 2022; 14:v14081636. [PMID: 35893701 PMCID: PMC9332783 DOI: 10.3390/v14081636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/19/2022] [Accepted: 07/23/2022] [Indexed: 12/13/2022] Open
Abstract
Serine incorporator 5 (SER5) is a protein that upon incorporation into virions inhibits HIV-1 infectivity by interfering with the ability of the Env glycoprotein to promote viral fusion. The mechanisms by which SER5 antagonizes HIV-1 fusion are not well understood. A recent study of SER5's structure revealed a lipid-binding pocket, suggesting the ability to sequester lipids. This finding, along with the well-documented modulation of HIV-1 infectivity by viral lipids, especially cholesterol, prompted our examination of SER5's effect on the general lipid order of the HIV-1 membrane. Pseudoviruses bearing the SER5-sensitive HXB2-Env and containing SER5 or SER2, a control protein that lacks antiviral activity, were analyzed using two distinct lipid-order probes. We show that SER5 incorporation does not noticeably affect the lipid order of pseudoviruses. Although viral cholesterol extraction reduces HIV-1 infectivity, SER5+ viruses are less sensitive to cholesterol extraction than the control samples. In contrast, the virus' sensitivity to cholesterol oxidation was not affected by SER5 incorporation. The hydrolytic release of sphingomyelin-sequestered cholesterol had a minimal impact on the apparent resistance to cholesterol extraction. Based on these results, we propose that a subpopulation of more stable Env glycoproteins responsible for the residual infectivity of SER5+ viruses is less sensitive to the cholesterol content of the viral membrane.
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Affiliation(s)
- Gokul Raghunath
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Yen-Cheng Chen
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Mariana Marin
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Hui Wu
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Gregory B. Melikyan
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
- Correspondence:
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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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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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10
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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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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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12
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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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HIV-1 entry: Duels between Env and host antiviral transmembrane proteins on the surface of virus particles. Curr Opin Virol 2021; 50:59-68. [PMID: 34390925 DOI: 10.1016/j.coviro.2021.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 12/18/2022]
Abstract
Human Immunodeficiency Virus type-1 (HIV-1) is the causative agent of AIDS. Its entry step is mediated by the envelope glycoprotein (Env). During the entry process, Env vastly changes its conformation. While non-liganded Env tends to have a closed structure, receptor-binding of Env opens its conformation, which leads to virus-cell membrane fusion. Single-molecule fluorescence resonance energy transfer (smFRET) imaging allows observation of these conformational changes on the virion surface. Nascent HIV-1 particles incorporate multiple host transmembrane proteins, some of which inhibit the entry process. The Env structure or its dynamics may determine the effectiveness of these antiviral mechanisms. Here, we review recent findings about the Env conformation changes on virus particles and inhibition of Env activities by virion-incorporated host transmembrane proteins.
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Downregulation of SERINC5 expression in buffy coats of HIV-1-infected patients with detectable or undetectable viral load. Mol Biol Rep 2021; 48:4247-4252. [PMID: 34097204 DOI: 10.1007/s11033-021-06438-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 05/26/2021] [Indexed: 10/21/2022]
Abstract
Among the host restriction factors against HIV, SERINC5 has been described in vitro, but the mRNA level of SERINC5 in vivo has been little studied. We compare SERINC5 expression in subjects with HIV-1 (highly active antiretroviral treatment (HAART) and HAART-naïve) with and without suppression of viral load. A cross-sectional study was performed with 107 individuals distributed as follows: 24 with HAART-naïve and detectable viral load (> 50 copies/mL), 13 with HAART and detectable viral load (> 50 copies/mL), 50 with HAART and undetectable viral load (≤ 50 copies/mL), and 20 without HIV-1. SERINC5 expression in buffy coats was determined using RT-qPCR. The viral load was determined using real-time PCR and the amount of CD4 + and CD8 + T-lymphocytes was measured using flow cytometry. The data were normalized with the Shapiro-Wilk test and the Kruskal-Wallis test was subsequently performed. The relative expression was compared with a T-test and the remaining data with the Mann-Whitney U-test. ANCOVA multiple linear regression analysis was performed between characteristics of patients with SERINC5 expression. The mean and SD of the SERINC5 expression in the three groups with HIV-1 was 0.9 ± 0.2 and without HIV-1 was 1.7 ± 0.14 (P < 0.001). Multiple linear regression did not show the participation of CD4 +, CD8 + , viral load, infection time, or treatment time. No differences in the SERINC5 expression were found among the studied groups of patients with HIV-1. When comparing the groups with and without HIV-1 infection, SERINC5 was downregulation in the HIV-1 groups.
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15
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Sauter D, Kirchhoff F. Evolutionary conflicts and adverse effects of antiviral factors. eLife 2021; 10:e65243. [PMID: 33450175 PMCID: PMC7811402 DOI: 10.7554/elife.65243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022] Open
Abstract
Human cells are equipped with a plethora of antiviral proteins protecting them against invading viral pathogens. In contrast to apoptotic or pyroptotic cell death, which serves as ultima ratio to combat viral infections, these cell-intrinsic restriction factors may prevent or at least slow down viral spread while allowing the host cell to survive. Nevertheless, their antiviral activity may also have detrimental effects on the host. While the molecular mechanisms underlying the antiviral activity of restriction factors are frequently well investigated, potential undesired effects of their antiviral functions on the host cell are hardly explored. With a focus on antiretroviral proteins, we summarize in this review how individual restriction factors may exert adverse effects as trade-off for efficient defense against attacking pathogens.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical CenterUlmGermany
- Institute of Medical Virology and Epidemiology of Viral Diseases, University Hospital TübingenTübingenGermany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical CenterUlmGermany
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16
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Zhang HG, Guo J, Yuan Y, Zuo Y, Liu J, Zhu L, Miao Y, Chen X, Jin L, Huang F, Ren T, He J, Shi W, Wen Z, Zhu C, Zheng H, Dong C, Qian F. Ubiquitin E3 Ligase c-Cbl Is a Host Negative Regulator of Nef Protein of HIV-1. Front Microbiol 2020; 11:597972. [PMID: 33329486 PMCID: PMC7710902 DOI: 10.3389/fmicb.2020.597972] [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: 08/23/2020] [Accepted: 10/28/2020] [Indexed: 11/23/2022] Open
Abstract
Nef is an accessory protein encoded by human immunodeficiency virus type-1 (HIV-1) and plays important roles in regulating HIV-1 infection and viral replication. Interestingly, HIV-1 Nef can promote degradation of numerous host proteins to disrupt cellular antiviral immune response. However, how HIV-1 Nef is degraded by host factors remains largely unexplored. Here, we identified c-Cbl as a host ubiquitin E3 ligase of HIV-1 Nef. We found that c-Cbl interacts with Nef and reduces protein levels of HIV-1 Nef. Further studies demonstrated that c-Cbl promoted Lys48-linked polyubiquitination of HIV-1 Nef, thus attenuating protein stability of HIV-1 Nef. Importantly, cellular c-Cbl ubiquitinated and degraded Nef proteins produced by HIV-1 NL4-3 virions, and ultimately attenuated HIV-1 virulence for infection of THP1 cells. This study reveals a ubiquitination and proteasome-dependent degradation mechanism of HIV-1 Nef protein, and could provide potential strategies for fighting against HIV-1.
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Affiliation(s)
- Hong-Guang Zhang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Jing Guo
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Yukang Yuan
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Yibo Zuo
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Jin Liu
- The Second Affiliated Hospital of Soochow University, The Affiliated Infectious Diseases Hospital of Soochow University, Suzhou, China
| | - Li Zhu
- The Second Affiliated Hospital of Soochow University, The Affiliated Infectious Diseases Hospital of Soochow University, Suzhou, China
| | - Ying Miao
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Xiangjie Chen
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Lincong Jin
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Fan Huang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Tengfei Ren
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Jiuyi He
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Weifeng Shi
- Department of Laboratory Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Zhenke Wen
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Chuanwu Zhu
- The Second Affiliated Hospital of Soochow University, The Affiliated Infectious Diseases Hospital of Soochow University, Suzhou, China
| | - Hui Zheng
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Chunsheng Dong
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.,Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou, China
| | - Feng Qian
- The Second Affiliated Hospital of Soochow University, The Affiliated Infectious Diseases Hospital of Soochow University, Suzhou, China
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