1
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Yang H, Pacheco J, Kim K, Ebrahimi D, Ito F, Chen XS. Molecular mechanism for regulating APOBEC3G DNA editing function by the non-catalytic domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584510. [PMID: 38559028 PMCID: PMC10980023 DOI: 10.1101/2024.03.11.584510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
APOBEC3G (A3G) belongs to the AID/APOBEC cytidine deaminase family and is essential for antiviral immunity. It contains two zinc-coordinated cytidine-deaminase (CD) domains. The N-terminal CD1 domain is non-catalytic but has a strong affinity for nucleic acids, whereas the C-terminal CD2 domain catalyzes C-to-U editing in single-stranded DNA. The interplay between the two domains in DNA binding and editing is not fully understood. Here, our studies on rhesus macaque A3G (rA3G) show that the DNA editing function in linear and hairpin loop DNA is greatly enhanced by AA or GA dinucleotide motifs present downstream (in the 3'-direction) but not upstream (in the 5'-direction) of the target-C editing sites. The effective distance between AA/GA and the target-C sites depends on the local DNA secondary structure. We present two co-crystal structures of rA3G bound to ssDNA containing AA and GA, revealing the contribution of the non-catalytic CD1 domain in capturing AA/GA DNA and explaining our biochemical observations. Our structural and biochemical findings elucidate the molecular mechanism underlying the cooperative function between the non-catalytic and the catalytic domains of A3G, which is critical for its antiviral role and its contribution to genome mutations in cancer.
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Affiliation(s)
- Hanjing Yang
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Josue Pacheco
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Kyumin Kim
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Diako Ebrahimi
- Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Fumiaki Ito
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA90095, USA
| | - Xiaojiang S. Chen
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
- Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
- Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA 90089, USA
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2
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Bao Q, Zhou J. Various strategies for developing APOBEC3G protectors to circumvent human immunodeficiency virus type 1. Eur J Med Chem 2023; 250:115188. [PMID: 36773550 DOI: 10.1016/j.ejmech.2023.115188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/18/2023] [Accepted: 02/04/2023] [Indexed: 02/09/2023]
Abstract
Host restriction factor APOBEC3G (A3G) efficiently restricts Vif-deficient HIV-1 by being packaged with progeny virions and causing the G to A mutation during HIV-1 viral DNA synthesis as the progeny virus infects new cells. HIV-1 expresses Vif protein to resist the activity of A3G by mediating A3G degradation. This process requires the self-association of Vif in concert with A3G proteins, protein chaperones, and factors of the ubiquitination machinery, which are potential targets to discover novel anti-HIV drugs. This review will describe compounds that have been reported so far to inhibit viral replication of HIV-1 by protecting A3G from Vif-mediated degradation.
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Affiliation(s)
- Qiqi Bao
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China; Drug Development and Innovation Center, College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China
| | - Jinming Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China; Drug Development and Innovation Center, College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, 321004, PR China.
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3
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Li YL, Langley CA, Azumaya CM, Echeverria I, Chesarino NM, Emerman M, Cheng Y, Gross JD. The structural basis for HIV-1 Vif antagonism of human APOBEC3G. Nature 2023; 615:728-733. [PMID: 36754086 PMCID: PMC10033410 DOI: 10.1038/s41586-023-05779-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 02/02/2023] [Indexed: 02/10/2023]
Abstract
The APOBEC3 (A3) proteins are host antiviral cellular proteins that hypermutate the viral genome of diverse viral families. In retroviruses, this process requires A3 packaging into viral particles1-4. The lentiviruses encode a protein, Vif, that antagonizes A3 family members by targeting them for degradation. Diversification of A3 allows host escape from Vif whereas adaptations in Vif enable cross-species transmission of primate lentiviruses. How this 'molecular arms race' plays out at the structural level is unknown. Here, we report the cryogenic electron microscopy structure of human APOBEC3G (A3G) bound to HIV-1 Vif, and the hijacked cellular proteins that promote ubiquitin-mediated proteolysis. A small surface explains the molecular arms race, including a cross-species transmission event that led to the birth of HIV-1. Unexpectedly, we find that RNA is a molecular glue for the Vif-A3G interaction, enabling Vif to repress A3G by ubiquitin-dependent and -independent mechanisms. Our results suggest a model in which Vif antagonizes A3G by intercepting it in its most dangerous form for the virus-when bound to RNA and on the pathway to packaging-to prevent viral restriction. By engaging essential surfaces required for restriction, Vif exploits a vulnerability in A3G, suggesting a general mechanism by which RNA binding helps to position key residues necessary for viral antagonism of a host antiviral gene.
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Affiliation(s)
- Yen-Li Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Caroline A Langley
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, USA
| | - Caleigh M Azumaya
- Fred Hutchinson Cancer Center, Electron Microscopy Shared Resource, Seattle, WA, USA
| | - Ignacia Echeverria
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA
- Quantitative Bioscience Institute, University of California, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Nicholas M Chesarino
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Michael Emerman
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Yifan Cheng
- Quantitative Bioscience Institute, University of California, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA.
- Quantitative Bioscience Institute, University of California, San Francisco, CA, USA.
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4
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Ito F, Alvarez-Cabrera AL, Liu S, Yang H, Shiriaeva A, Zhou ZH, Chen XS. Structural basis for HIV-1 antagonism of host APOBEC3G via Cullin E3 ligase. SCIENCE ADVANCES 2023; 9:eade3168. [PMID: 36598981 PMCID: PMC9812381 DOI: 10.1126/sciadv.ade3168] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Human APOBEC3G (A3G) is a virus restriction factor that inhibits HIV-1 replication and triggers lethal hypermutation on viral reverse transcripts. HIV-1 viral infectivity factor (Vif) breaches this host A3G immunity by hijacking a cellular E3 ubiquitin ligase complex to target A3G for ubiquitination and degradation. The molecular mechanism of A3G targeting by Vif-E3 ligase is unknown, limiting the antiviral efforts targeting this host-pathogen interaction crucial for HIV-1 infection. Here, we report the cryo-electron microscopy structures of A3G bound to HIV-1 Vif in complex with T cell transcription cofactor CBF-β and multiple components of the Cullin-5 RING E3 ubiquitin ligase. The structures reveal unexpected RNA-mediated interactions of Vif with A3G primarily through A3G's noncatalytic domain, while A3G's catalytic domain is poised for ubiquitin transfer. These structures elucidate the molecular mechanism by which HIV-1 Vif hijacks the host ubiquitin ligase to specifically target A3G to establish infection and offer structural information for the rational development of antiretroviral therapeutics.
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Affiliation(s)
- Fumiaki Ito
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Ana L. Alvarez-Cabrera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
| | - Shiheng Liu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
| | - Hanjing Yang
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Anna Shiriaeva
- Department of Biological Chemistry, UCLA, Los Angeles, CA, USA
| | - Z. Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
| | - Xiaojiang S. Chen
- Molecular and Computational Biology, Departments of Biological Sciences, University of Southern California, Los Angeles, CA, USA
- Genetic, Molecular, and Cellular Biology Program, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA
- Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA, USA
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5
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Yang H, Kim K, Li S, Pacheco J, Chen XS. Structural basis of sequence-specific RNA recognition by the antiviral factor APOBEC3G. Nat Commun 2022; 13:7498. [PMID: 36470880 PMCID: PMC9722718 DOI: 10.1038/s41467-022-35201-9] [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: 05/11/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022] Open
Abstract
An essential step in restricting HIV infectivity by the antiviral factor APOBEC3G is its incorporation into progeny virions via binding to HIV RNA. However, the mechanism of APOBEC3G capturing viral RNA is unknown. Here, we report crystal structures of a primate APOBEC3G bound to different types of RNAs, revealing that APOBEC3G specifically recognizes unpaired 5'-AA-3' dinucleotides, and to a lesser extent, 5'-GA-3' dinucleotides. APOBEC3G binds to the common 3'A in the AA/GA motifs using an aromatic/hydrophobic pocket in the non-catalytic domain. It binds to the 5'A or 5'G in the AA/GA motifs using an aromatic/hydrophobic groove conformed between the non-catalytic and catalytic domains. APOBEC3G RNA binding property is distinct from that of the HIV nucleocapsid protein recognizing unpaired guanosines. Our findings suggest that the sequence-specific RNA recognition is critical for APOBEC3G virion packaging and restricting HIV infectivity.
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Affiliation(s)
- Hanjing Yang
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, Los Angeles, CA 90089 USA
| | - Kyumin Kim
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, Los Angeles, CA 90089 USA
| | - Shuxing Li
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, Los Angeles, CA 90089 USA ,grid.42505.360000 0001 2156 6853Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA 90089 USA
| | - Josue Pacheco
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, Los Angeles, CA 90089 USA
| | - Xiaojiang S. Chen
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, Los Angeles, CA 90089 USA ,grid.42505.360000 0001 2156 6853Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA 90089 USA ,grid.42505.360000 0001 2156 6853Genetic, Molecular and Cellular Biology Program, Keck School of Medicine, Los Angeles, CA 90033 USA ,grid.42505.360000 0001 2156 6853Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033 USA
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6
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Papini C, Wang Z, Kudalkar SN, Schrank TP, Tang S, Sasaki T, Wu C, Tejada B, Ziegler SJ, Xiong Y, Issaeva N, Yarbrough WG, Anderson KS. Exploring ABOBEC3A and APOBEC3B substrate specificity and their role in HPV positive head and neck cancer. iScience 2022; 25:105077. [PMID: 36164654 PMCID: PMC9508485 DOI: 10.1016/j.isci.2022.105077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 12/03/2022] Open
Abstract
APOBEC3 family members are cytidine deaminases catalyzing conversion of cytidine to uracil. Many studies have established a link between APOBEC3 expression and cancer development and progression, especially APOBEC3A (A3A) and APOBEC3B (A3B). Preclinical studies with human papillomavirus positive (HPV+) head and neck squamous cell carcinoma (HNSCC) and clinical trial specimens revealed induction of A3B, but not A3A expression after demethylation. We examined the kinetic features of the cytidine deaminase activity for full length A3B and found that longer substrates and a purine at −2 position favored by A3B, whereas A3A prefers shorter substrates and an adenine or thymine at −2 position. The importance and biological significance of A3B catalytic activity rather than A3A and a preference for purine at the −2 position was also established in HPV+ HNSCCs. Our study explored factors influencing formation of A3A and A3B-related cancer mutations that are essential for understanding APOBEC3-related carcinogenesis and facilitating drug discovery. A3B is upregulated after 5-AzaC treatment and related to 5-AzaC sensitivity in HPV+ HNSCC Full-length A3B prefers longer substrates and a purine at −2 site biochemically A3B also prefers a purine at −2 site in both HPV+ and HPV− HNSCC cells A3B signature at -2 site linked to poor patient survival in HPV+ HNSCC low smokers
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Affiliation(s)
- Christina Papini
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - Zechen Wang
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - Shalley N Kudalkar
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - Travis Parke Schrank
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Su Tang
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - Tomoaki Sasaki
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - Cory Wu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Brandon Tejada
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Samantha J Ziegler
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Natalia Issaeva
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Pathology and Lab Medicine, Lineberger Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Wendell G Yarbrough
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Pathology and Lab Medicine, Lineberger Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Karen S Anderson
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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7
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Small-Angle X-ray Scattering (SAXS) Measurements of APOBEC3G Provide Structural Basis for Binding of Single-Stranded DNA and Processivity. Viruses 2022; 14:v14091974. [PMID: 36146779 PMCID: PMC9505750 DOI: 10.3390/v14091974] [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: 06/29/2022] [Revised: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 11/17/2022] Open
Abstract
APOBEC3 enzymes are polynucleotide deaminases, converting cytosine to uracil on single-stranded DNA (ssDNA) and RNA as part of the innate immune response against viruses and retrotransposons. APOBEC3G is a two-domain protein that restricts HIV. Although X-ray single-crystal structures of individual catalytic domains of APOBEC3G with ssDNA as well as full-length APOBEC3G have been solved recently, there is little structural information available about ssDNA interaction with the full-length APOBEC3G or any other two-domain APOBEC3. Here, we investigated the solution-state structures of full-length APOBEC3G with and without a 40-mer modified ssDNA by small-angle X-ray scattering (SAXS), using size-exclusion chromatography (SEC) immediately prior to irradiation to effect partial separation of multi-component mixtures. To prevent cytosine deamination, the target 2′-deoxycytidine embedded in 40-mer ssDNA was replaced by 2′-deoxyzebularine, which is known to inhibit APOBEC3A, APOBEC3B and APOBEC3G when incorporated into short ssDNA oligomers. Full-length APOBEC3G without ssDNA comprised multiple multimeric species, of which tetramer was the most scattering species. The structure of the tetramer was elucidated. Dimeric interfaces significantly occlude the DNA-binding interface, whereas the tetrameric interface does not. This explains why dimers completely disappeared, and monomeric protein species became dominant, when ssDNA was added. Data analysis of the monomeric species revealed a full-length APOBEC3G–ssDNA complex that gives insight into the observed “jumping” behavior revealed in studies of enzyme processivity. This solution-state SAXS study provides the first structural model of ssDNA binding both domains of APOBEC3G and provides data to guide further structural and enzymatic work on APOBEC3–ssDNA complexes.
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8
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McDonnell MM, Karvonen SC, Gaba A, Flath B, Chelico L, Emerman M. Highly-potent, synthetic APOBEC3s restrict HIV-1 through deamination-independent mechanisms. PLoS Pathog 2021; 17:e1009523. [PMID: 34170969 PMCID: PMC8266076 DOI: 10.1371/journal.ppat.1009523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/08/2021] [Accepted: 06/07/2021] [Indexed: 02/07/2023] Open
Abstract
The APOBEC3 (A3) genes encode cytidine deaminase proteins with potent antiviral and anti-retroelement activity. This locus is characterized by duplication, recombination, and deletion events that gave rise to the seven A3s found in primates. These include three single deaminase domain A3s (A3A, A3C, and A3H) and four double deaminase domain A3s (A3B, A3D, A3F, and A3G). The most potent of the A3 proteins against HIV-1 is A3G. However, it is not clear if double deaminase domain A3s have a generalized functional advantage to restrict HIV-1. In order to test whether superior restriction factors could be created by genetically linking single A3 domains into synthetic double domains, we linked A3C and A3H single domains in novel combinations. We found that A3C/A3H double domains acquired enhanced antiviral activity that is at least as potent, if not better than, A3G. Although these synthetic double domain A3s package into budding virions more efficiently than their respective single domains, this does not fully explain their gain of antiviral potency. The antiviral activity is conferred both by cytidine-deaminase dependent and independent mechanisms, with the latter correlating to an increase in RNA binding affinity. T cell lines expressing this A3C-A3H super restriction factor are able to control replicating HIV-1ΔVif infection to similar levels as A3G. Together, these data show that novel combinations of A3 domains are capable of gaining potent antiviral activity to levels similar to the most potent genome-encoded A3s, via a primarily non-catalytic mechanism.
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Affiliation(s)
- Mollie M. McDonnell
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, United States of America
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Suzanne C. Karvonen
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Amit Gaba
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Ben Flath
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Linda Chelico
- Department of Biochemistry, Microbiology, and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Michael Emerman
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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9
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Insights into the Structures and Multimeric Status of APOBEC Proteins Involved in Viral Restriction and Other Cellular Functions. Viruses 2021; 13:v13030497. [PMID: 33802945 PMCID: PMC8002816 DOI: 10.3390/v13030497] [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: 02/15/2021] [Revised: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 12/16/2022] Open
Abstract
Apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC) proteins belong to a family of deaminase proteins that can catalyze the deamination of cytosine to uracil on single-stranded DNA or/and RNA. APOBEC proteins are involved in diverse biological functions, including adaptive and innate immunity, which are critical for restricting viral infection and endogenous retroelements. Dysregulation of their functions can cause undesired genomic mutations and RNA modification, leading to various associated diseases, such as hyper-IgM syndrome and cancer. This review focuses on the structural and biochemical data on the multimerization status of individual APOBECs and the associated functional implications. Many APOBECs form various multimeric complexes, and multimerization is an important way to regulate functions for some of these proteins at several levels, such as deaminase activity, protein stability, subcellular localization, protein storage and activation, virion packaging, and antiviral activity. The multimerization of some APOBECs is more complicated than others, due to the associated complex RNA binding modes.
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10
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Maiti A, Hou S, Schiffer CA, Matsuo H. Interactions of APOBEC3s with DNA and RNA. Curr Opin Struct Biol 2021; 67:195-204. [PMID: 33486429 DOI: 10.1016/j.sbi.2020.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/25/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023]
Abstract
APOBEC3 enzymes are key enzymes in our innate immune system regulating antiviral response in HIV and unfortunately adding diversity in cancer as they deaminate cytosine. Seven unique single and double domain APOBEC3s provide them with unique activity and specificity profiles for this deamination. Recent crystal and NMR structures of APOBEC3 complexes are unraveling the variety of epitopes involved in binding nucleic acids, including at the catalytic site, elsewhere on the catalytic domain and in the inactive N-terminal domain. The interplay between these diverse interactions is critical to uncovering the mechanisms by which APOBEC3s recognize and process their substrates.
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Affiliation(s)
- Atanu Maiti
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Shurong Hou
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.
| | - Hiroshi Matsuo
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
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