1
|
Volcic M, Wiesmüller L, Kirchhoff F. Small but Highly Versatile: The Viral Accessory Protein Vpu. Annu Rev Virol 2023; 10:243-259. [PMID: 37406340 DOI: 10.1146/annurev-virology-111821-100816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
Human and simian immunodeficiency viruses (HIVs and SIVs, respectively) encode several small proteins (Vif, Vpr, Nef, Vpu, and Vpx) that are called accessory because they are not generally required for viral replication in cell culture. However, they play complex and important roles for viral immune evasion and spread in vivo. Here, we discuss the diverse functions and the relevance of the viral protein U (Vpu) that is expressed from a bicistronic RNA during the late stage of the viral replication cycle and found only in HIV-1 and closely related SIVs. It is well established that Vpu counteracts the restriction factor tetherin, mediates degradation of the primary viral CD4 receptors, and inhibits activation of the transcription factor nuclear factor kappa B. Recent studies identified additional activities and provided new insights into the sophisticated mechanisms by which Vpu enhances and prolongs the release of fully infectious viral particles. In addition, it has been shown that Vpu prevents superinfection not only by degrading CD4 but also by modulating DNA repair mechanisms to promote degradation of nuclear viral complementary DNA in cells that are already productively infected.
Collapse
Affiliation(s)
- Meta Volcic
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany;
| | - Lisa Wiesmüller
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, Ulm University Medical Center, Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany;
| |
Collapse
|
2
|
Ikeda T, Shimizu R, Nasser H, Carpenter MA, Cheng AZ, Brown WL, Sauter D, Harris RS. APOBEC3 degradation is the primary function of HIV-1 Vif determining virion infectivity in the myeloid cell line THP-1. mBio 2023; 14:e0078223. [PMID: 37555667 PMCID: PMC10470580 DOI: 10.1128/mbio.00782-23] [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: 03/28/2023] [Accepted: 06/22/2023] [Indexed: 08/10/2023] Open
Abstract
HIV-1 must overcome multiple innate antiviral mechanisms to replicate in CD4+ T lymphocytes and macrophages. Previous studies have demonstrated that the apolipoprotein B mRNA editing enzyme polypeptide-like 3 (APOBEC3, A3) family of proteins (at least A3D, A3F, A3G, and stable A3H haplotypes) contribute to HIV-1 restriction in CD4+ T lymphocytes. Virus-encoded virion infectivity factor (Vif) counteracts this antiviral activity by degrading A3 enzymes allowing HIV-1 replication in infected cells. In addition to A3 proteins, Vif also targets other cellular proteins in CD4+ T lymphocytes, including PPP2R5 proteins. However, whether Vif primarily degrades only A3 proteins during viral replication is currently unknown. Herein, we describe the development and characterization of A3F-, A3F/A3G-, and A3A-to-A3G-null THP-1 cells. In comparison to Vif-proficient HIV-1, Vif-deficient viruses have substantially reduced infectivity in parental and A3F-null THP-1 cells, and a more modest decrease in infectivity in A3F/A3G-null cells. Remarkably, disruption of A3A-A3G protein expression completely restores the infectivity of Vif-deficient viruses in THP-1 cells. These results indicate that the primary function of Vif during infectious HIV-1 production from THP-1 cells is the targeting and degradation of A3 enzymes. IMPORTANCE HIV-1 Vif neutralizes the HIV-1 restriction activity of A3 proteins. However, it is currently unclear whether Vif has additional essential cellular targets. To address this question, we disrupted A3A to A3G genes in the THP-1 myeloid cell line using CRISPR and compared the infectivity of wild-type HIV-1 and Vif mutants with the selective A3 neutralization activities. Our results demonstrate that the infectivity of Vif-deficient HIV-1 and the other Vif mutants is fully restored by ablating the expression of cellular A3A to A3G proteins. These results indicate that A3 proteins are the only essential target of Vif that is required for fully infectious HIV-1 production from THP-1 cells.
Collapse
Affiliation(s)
- Terumasa Ikeda
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
| | - Ryo Shimizu
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
- Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Hesham Nasser
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
- Department of Clinical Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Michael A. Carpenter
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Adam Z. Cheng
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - William L. Brown
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Reuben S. Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, USA
| |
Collapse
|
3
|
Ikeda T, Shimizu R, Nasser H, Carpenter MA, Cheng AZ, Brown WL, Sauter D, Harris RS. APOBEC3 degradation is the primary function of HIV-1 Vif for virus replication in the myeloid cell line THP-1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.28.534666. [PMID: 37034786 PMCID: PMC10081227 DOI: 10.1101/2023.03.28.534666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
HIV-1 must overcome multiple innate antiviral mechanisms to replicate in CD4 + T lymphocytes and macrophages. Previous studies have demonstrated that the APOBEC3 (A3) family of proteins (at least A3D, A3F, A3G, and stable A3H haplotypes) contribute to HIV-1 restriction in CD4 + T lymphocytes. Virus-encoded virion infectivity factor (Vif) counteracts this antiviral activity by degrading A3 enzymes allowing HIV-1 replication in infected cells. In addition to A3 proteins, Vif also targets other cellular proteins in CD4 + T lymphocytes, including PPP2R5 proteins. However, whether Vif primarily degrades only A3 proteins or has additional essential targets during viral replication is currently unknown. Herein, we describe the development and characterization of A3F -, A3F/A3G -, and A3A -to- A3G -null THP-1 cells. In comparison to Vif-proficient HIV-1, Vif-deficient viruses have substantially reduced infectivity in parental and A3F -null THP-1 cells, and a more modest decrease in infectivity in A3F/A3G -null cells. Remarkably, disruption of A3Aâ€"A3G protein expression completely restores the infectivity of Vif-deficient viruses in THP-1 cells. These results indicate that the primary function of Vif during HIV-1 replication in THP-1 cells is the targeting and degradation of A3 enzymes. Importance HIV-1 Vif neutralizes the HIV-1 restriction activity of A3 proteins. However, it is currently unclear whether Vif has additional essential cellular targets. To address this question, we disrupted A3A to A3G genes in the THP-1 myeloid cell line using CRISPR and compared the infectivity of wildtype HIV-1 and Vif mutants with the selective A3 neutralization activities. Our results demonstrate that the infectivity of Vif-deficient HIV-1 and the other Vif mutants is fully restored by ablating the expression of cellular A3A to A3G proteins. These results indicate that A3 proteins are the only essential target of Vif that is required for HIV-1 replication in THP-1 cells.
Collapse
Affiliation(s)
- Terumasa Ikeda
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto 8600811, Japan
| | - Ryo Shimizu
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto 8600811, Japan
- Graduate School of Medical Sciences, Kumamoto University, Kumamoto 8600811, Japan
| | - Hesham Nasser
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto 8600811, Japan
- Department of Clinical Pathology, Faculty of Medicine, Suez Canal University, Ismailia 41511, Egypt
| | - Michael A. Carpenter
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| | - Adam Z. Cheng
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - William L. Brown
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen 72076, Germany
| | - Reuben S. Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| |
Collapse
|
4
|
Vollmers S, Lobermeyer A, Körner C. The New Kid on the Block: HLA-C, a Key Regulator of Natural Killer Cells in Viral Immunity. Cells 2021; 10:cells10113108. [PMID: 34831331 PMCID: PMC8620871 DOI: 10.3390/cells10113108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/01/2022] Open
Abstract
The human leukocyte antigen system (HLA) is a cluster of highly polymorphic genes essential for the proper function of the immune system, and it has been associated with a wide range of diseases. HLA class I molecules present intracellular host- and pathogen-derived peptides to effector cells of the immune system, inducing immune tolerance in healthy conditions or triggering effective immune responses in pathological situations. HLA-C is the most recently evolved HLA class I molecule, only present in humans and great apes. Differentiating from its older siblings, HLA-A and HLA-B, HLA-C exhibits distinctive features in its expression and interaction partners. HLA-C serves as a natural ligand for multiple members of the killer-cell immunoglobulin-like receptor (KIR) family, which are predominately expressed by natural killer (NK) cells. NK cells are crucial for the early control of viral infections and accumulating evidence indicates that interactions between HLA-C and its respective KIR receptors determine the outcome and progression of viral infections. In this review, we focus on the unique role of HLA-C in regulating NK cell functions and its consequences in the setting of viral infections.
Collapse
|
5
|
Abstract
Natural Killer (NK) cells are key effectors of the innate immune system which represent the first line of defense against viral infections. NK cell activation depends on the engagement of a complex receptor repertoire expressed on their surface, consisting of both activating and inhibitory receptors. Among the known NK cell receptors, the family of killer Ig-like receptors (KIRs) consists in activating/inhibitory receptors that interact with specific human leukocyte antigen (HLA) molecules expressed on target cells. In particular, the expression of peculiar KIRs have been reported to be associated to viral infection susceptibility. Interestingly, a significant association between the development and onset of different human pathologies, such as tumors, neurodegeneration and infertility, and a clonal KIRs expression on NK cells has been described in presence of viral infections, supporting the crucial role of KIRs in defining the effect of viral infections in different tissues and organs. This review aims to report the state of art about the role of KIRs receptors in NK cell activation and viral infection control.
Collapse
|
6
|
APOBEC3F Constitutes a Barrier to Successful Cross-Species Transmission of Simian Immunodeficiency Virus SIVsmm to Humans. J Virol 2021; 95:e0080821. [PMID: 34132575 DOI: 10.1128/jvi.00808-21] [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] [Indexed: 12/24/2022] Open
Abstract
Simian immunodeficiency virus infecting sooty mangabeys (SIVsmm) has been transmitted to humans on at least nine occasions, giving rise to human immunodeficiency virus type 2 (HIV-2) groups A to I. SIVsmm isolates replicate in human T cells and seem capable of overcoming major human restriction factors without adaptation. However, only groups A and B are responsible for the HIV-2 epidemic in sub-Saharan Africa, and it is largely unclear whether adaptive changes were associated with spread in humans. To address this, we examined the sensitivity of infectious molecular clones (IMCs) of five HIV-2 strains and representatives of five different SIVsmm lineages to various APOBEC3 proteins. We confirmed that SIVsmm strains replicate in human T cells, albeit with more variable replication fitness and frequently lower efficiency than HIV-2 IMCs. Efficient viral propagation was generally dependent on intact vif genes, highlighting the need for counteraction of APOBEC3 proteins. On average, SIVsmm was more susceptible to inhibition by human APOBEC3D, -F, -G, and -H than HIV-2. For example, human APOBEC3F reduced infectious virus yield of SIVsmm by ∼80% but achieved only ∼40% reduction in the case of HIV-2. Functional and mutational analyses of human- and monkey-derived alleles revealed that an R128T polymorphism in APOBEC3F contributes to species-specific counteraction by HIV-2 and SIVsmm Vifs. In addition, a T84S substitution in SIVsmm Vif increased its ability to counteract human APOBEC3F. Altogether, our results confirm that SIVsmm Vif proteins show intrinsic activity against human APOBEC3 proteins but also demonstrate that epidemic HIV-2 strains evolved an increased ability to counteract this class of restriction factors during human adaptation. IMPORTANCE Viral zoonoses pose a significant threat to human health, and it is important to understand determining factors. SIVs infecting great apes gave rise to HIV-1. In contrast, SIVs infecting African monkey species have not been detected in humans, with one notable exception. SIVsmm from sooty mangabeys has crossed the species barrier to humans on at least nine independent occasions and seems capable of overcoming many innate defense mechanisms without adaptation. Here, we confirmed that SIVsmm Vif proteins show significant activity against human APOBEC3 proteins. Our analyses also revealed, however, that different lineages of SIVsmm are significantly more susceptible to inhibition by various human APOBEC3 proteins than HIV-2 strains. Mutational analyses suggest that an R128T substitution in APOBEC3F and a T84S change in Vif contribute to species-specific counteraction by HIV-2 and SIVsmm. Altogether, our results support that epidemic HIV-2 strains acquired increased activity against human APOBEC3 proteins to clear this restrictive barrier.
Collapse
|
7
|
Critical Review of Existing MHC I Immunopeptidome Isolation Methods. Molecules 2020; 25:molecules25225409. [PMID: 33228004 PMCID: PMC7699222 DOI: 10.3390/molecules25225409] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/06/2020] [Accepted: 11/17/2020] [Indexed: 12/15/2022] Open
Abstract
Major histocompatibility complex class I (MHC I) plays a crucial role in the development of adaptive immune response in vertebrates. MHC molecules are cell surface protein complexes loaded with short peptides and recognized by the T-cell receptors (TCR). Peptides associated with MHC are named immunopeptidome. The MHC I immunopeptidome is produced by the proteasome degradation of intracellular proteins. The knowledge of the immunopeptidome repertoire facilitates the creation of personalized antitumor or antiviral vaccines. A huge number of publications on the immunopeptidome diversity of different human and mouse biological samples-plasma, peripheral blood mononuclear cells (PBMCs), and solid tissues, including tumors-appeared in the scientific journals in the last decade. Significant immunopeptidome identification efficiency was achieved by advances in technology: the immunoprecipitation of MHC and mass spectrometry-based approaches. Researchers optimized common strategies to isolate MHC-associated peptides for individual tasks. They published many protocols with differences in the amount and type of biological sample, amount of antibodies, type and amount of insoluble support, methods of post-fractionation and purification, and approaches to LC-MS/MS identification of immunopeptidome. These parameters have a large impact on the final repertoire of isolated immunopeptidome. In this review, we summarize and compare immunopeptidome isolation techniques with an emphasis on the results obtained.
Collapse
|