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Feng B, Zhang J, Liu Z, Xu Y, Hu H. Discovery and biological evaluation of novel dual PTP1B and ACP1 inhibitors for the treatment of insulin resistance. Bioorg Med Chem 2024; 97:117545. [PMID: 38070352 DOI: 10.1016/j.bmc.2023.117545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/20/2023] [Accepted: 12/04/2023] [Indexed: 12/30/2023]
Abstract
In this study, a virtual screening pipeline comprising ligand-based and structure-based approaches was established and applied for the identification of dual PTP1B and ACP1 inhibitors. As a result, a series of benzoic acid derivatives was discovered, and compound H3 and S6 demonstrated PTP1B and ACP1 inhibitory activity, with IC50 values of 3.5 and 8.2 μM for PTP1B, and 2.5 and 5.2 μM for ACP1, respectively. Molecular dynamics simulations illustrated that H3 interacted with critical residues in the active site, such as Cys215 and Arg221 for PTP1B, and Cys17 and Arg18 for ACP1. Enzymatic kinetic research indicated that identified inhibitors competitively inhibited PTP1B and ACP1. Additionally, cellular assays demonstrated that H3 and S6 effectively increased glucose uptake in insulin-resistant HepG2 cells while displaying very limited cytotoxicity at their effective concentrations. In summary, H3 and S6 represent novel dual-target inhibitors for PTP1B and ACP1, warranting further investigation as potential agents for the treatment of diabetes.
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Affiliation(s)
- Bo Feng
- Department of Pharmacy, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Jie Zhang
- Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhen Liu
- Department of Neurology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Yuan Xu
- Department of Pharmacy, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China.
| | - Huabin Hu
- Centre for Cancer Drug Discovery, Division of Cancer Therapeutics, The Institute of Cancer Research, London, UK; Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, SE-751 24 Uppsala, Sweden.
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2
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Jose L, Gonzalez J, Kessinger E, Androphy EJ, DeSmet M. Focal Adhesion Kinase Binds to the HPV E2 Protein to Regulate Initial Replication after Infection. Pathogens 2023; 12:1203. [PMID: 37887719 PMCID: PMC10609836 DOI: 10.3390/pathogens12101203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/24/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023] Open
Abstract
Human papillomaviruses are small DNA tumor viruses that infect cutaneous and mucosal epithelia. The viral lifecycle is linked to the differentiation status of the epithelium. During initial viral infection, the genomes replicate at a low copy number but the mechanism(s) the virus uses to control the copy number during this stage is not known. In this study, we demonstrate that the tyrosine kinase focal adhesion kinase (FAK) binds to and phosphorylates the high-risk viral E2 protein, the key regulator of HPV replication. The depletion of FAK with a specific PROTAC had no effect on viral DNA content in keratinocytes that already maintain HPV-16 and HPV-31 episomes. In contrast, the depletion of FAK significantly increased HPV-16 DNA content in keratinocytes infected with HPV-16 quasiviruses. These data imply that FAK prevents the over-replication of the HPV genome after infection through the interaction and phosphorylation of the E2 protein.
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Affiliation(s)
- Leny Jose
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (E.K.); (E.J.A.)
| | - Jessica Gonzalez
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Emma Kessinger
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (E.K.); (E.J.A.)
| | - Elliot J. Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (E.K.); (E.J.A.)
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (E.K.); (E.J.A.)
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Kuehner F, Stubenrauch F. Functions of Papillomavirus E8^E2 Proteins in Tissue Culture and In Vivo. Viruses 2022; 14:v14050953. [PMID: 35632695 PMCID: PMC9143700 DOI: 10.3390/v14050953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 12/04/2022] Open
Abstract
Papillomaviruses (PV) replicate in undifferentiated keratinocytes at low levels and to high levels in differentiated cells. The restricted replication in undifferentiated cells is mainly due to the expression of the conserved viral E8^E2 repressor protein, a fusion protein consisting of E8 and the hinge, DNA-binding, and dimerization domain of E2. E8^E2 binds to viral genomes and represses viral transcription and genome replication by recruiting cellular NCoR/SMRT-HDAC3 corepressor complexes. Tissue culture experiments have revealed that E8^E2 modulates long-term maintenance of extrachromosomal genomes, productive replication, and immortalization properties in a virus type-dependent manner. Furthermore, in vivo experiments have indicated that Mus musculus PV1 E8^E2 is required for tumor formation in immune-deficient mice. In summary, E8^E2 is a crucial inhibitor whose levels might determine the outcome of PV infections.
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Fernandes AO, Barros GS, Batista MVA. Metatranscriptomics Analysis Reveals Diverse Viral RNA in Cutaneous Papillomatous Lesions of Cattle. Evol Bioinform Online 2022; 18:11769343221083960. [PMID: 35633934 PMCID: PMC9133864 DOI: 10.1177/11769343221083960] [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: 11/05/2021] [Accepted: 02/09/2022] [Indexed: 11/17/2022] Open
Abstract
Bovine papillomavirus (BPV) is associated with bovine papillomatosis, a disease that forms benign warts in epithelial tissues, as well as malignant lesions. Previous studies have detected a co-infection between BPV and other viruses, making it likely that these co-infections could influence disease progression. Therefore, this study aimed to identify and annotate viral genes in cutaneous papillomatous lesions of cattle. Sequences were obtained from the GEO database, and an RNA-seq computational pipeline was used to analyze 3 libraries from bovine papillomatous lesions. In total, 25 viral families were identified, including Poxviridae, Retroviridae, and Herpesviridae. All libraries shared similarities in the viruses and genes found. The viral genes shared similarities with BPV genes, especially for functions as virion entry pathway, malignant progression by apoptosis suppression and immune system control. Therefore, this study presents relevant data extending the current knowledge regarding the viral microbiome in BPV lesions and how other viruses could affect this disease.
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Affiliation(s)
- Adriana O Fernandes
- Laboratory of Molecular Genetics and Biotechnology (GMBio), Department of Biology, Center for Biological and Health Sciences, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
| | - Gerlane S Barros
- Laboratory of Molecular Genetics and Biotechnology (GMBio), Department of Biology, Center for Biological and Health Sciences, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
| | - Marcus VA Batista
- Laboratory of Molecular Genetics and Biotechnology (GMBio), Department of Biology, Center for Biological and Health Sciences, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
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5
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Jose L, Gilson T, Androphy EJ, DeSmet M. Regulation of the Human Papillomavirus Lifecyle through Post-Translational Modifications of the Viral E2 Protein. Pathogens 2021; 10:793. [PMID: 34201556 PMCID: PMC8308518 DOI: 10.3390/pathogens10070793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/13/2021] [Accepted: 06/18/2021] [Indexed: 01/28/2023] Open
Abstract
The human papillomavirus (HPV) is a DNA tumor virus that infects cutaneous and mucosal epithelia where high-risk (HR) HPV infections lead to cervical, oropharyngeal, and anogenital cancers. Worldwide, nearly 5% of all cancers are caused by HR HPV. The viral E2 protein is essential for episomal replication throughout the viral lifecycle. The E2 protein is regulated by phosphorylation, acetylation, sumoylation, and ubiquitination. In this mini-review, we summarize the recent advancements made to identify post translational modifications within E2 and their ability to control viral replication.
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Affiliation(s)
- Leny Jose
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (T.G.); (E.J.A.)
| | - Timra Gilson
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (T.G.); (E.J.A.)
| | - Elliot J. Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (T.G.); (E.J.A.)
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (L.J.); (T.G.); (E.J.A.)
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6
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BRD4S interacts with viral E2 protein to limit human papillomavirus late transcription. J Virol 2021; 95:JVI.02032-20. [PMID: 33731454 PMCID: PMC8139696 DOI: 10.1128/jvi.02032-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The E2 protein encoded by human papillomaviruses (HPV) is a sequence-specific DNA-binding protein that recruits viral and cellular proteins. Bromodomain-containing protein 4 (BRD4) is a highly conserved interactor for E2 proteins that has been linked to E2's functions as transcription modulator, activator of viral replication and segregation factor for viral genomes. In addition to BRD4, a short form of BRD4 (BRD4S) is expressed from the BRD4 gene which lacks the C-terminal domain of BRD4. E2 proteins interact with the C-terminal motif (CTM) of BRD4, but a recent study suggested that the phospho-dependent interaction domain (PDID) and the basic interaction domain (BID) in BRD4 also bind to E2. These domains are also present in BRD4S. We now find that HPV31 E2 interacts with the isolated PDID domain in living cells and also with BRD4S which is present in detectable amounts in HPV-positive cell lines and is recruited into HPV31 E1 and E2 induced replication foci. Overexpression and knockdown experiments surprisingly indicate that BRD4S inhibits activities of E2. In line with that, the specific knockdown of BRD4S in the HPV31-positive CIN612-9E cell line induces mainly late viral transcripts. This occurs only in undifferentiated but not differentiated cells in which the productive viral replication cycle is induced. These data suggest that the BRD4S-E2 interaction is important to prevent HPV late gene expression in undifferentiated keratinocytes which may contribute to immune evasion and HPV persistence.ImportanceHuman papillomaviruses (HPV) have coevolved with their host by using cellular factors like bromodomain-containing protein 4 (BRD4) to control viral processes such as genome maintenance, gene expression and replication. We here show that, in addition to the C-terminal motif in BRD4, the phospho-dependent interaction domain in BRD4 interacts with E2 proteins which enable the recruitment of BRD4S, the short isoform of BRD4, to E2. Knock-down and overexpression of BRD4S reveals that BRD4S is a negative regulator of E2 activities. Importantly, the knockdown of BRD4S induces mainly L1 transcripts in undifferentiated CIN612-9E cells, which maintain replicating HPV31 genomes. Our study reveals an inhibitory role of BRD4S on HPV transcription, which may serve as an immune escape mechanism by the suppression of L1 transcripts and thus contribute to the establishment of persistent HPV infections.
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Pyk2 Regulates Human Papillomavirus Replication by Tyrosine Phosphorylation of the E2 Protein. J Virol 2020; 94:JVI.01110-20. [PMID: 32727877 DOI: 10.1128/jvi.01110-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/24/2020] [Indexed: 12/29/2022] Open
Abstract
The human papillomavirus (HPV) E2 protein is a key regulator of viral transcription and replication. In this study, we demonstrate that the nonreceptor tyrosine kinase Pyk2 phosphorylates tyrosine 131 in the E2 transactivation domain. Both depletion of Pyk2 and treatment with a Pyk2 kinase inhibitor increased viral DNA content in keratinocytes that maintain viral episomes. The tyrosine-to-glutamic acid (E) mutant Y131E, which may mimic phosphotyrosine, failed to stimulate transient DNA replication, and genomes with this mutation were unable to establish stable episomes in keratinocytes. Using coimmunoprecipitation assays, we demonstrate that the Y131E is defective for binding to the C-terminal motif (CTM) of Bromodomain-containing protein 4 (Brd4). These data imply that HPV replication depends on E2 Y131 interaction with the pTEFb binding domain of Brd4.IMPORTANCE Human papillomaviruses are the major causative agents of cervical, oral, and anal cancers. The present study demonstrates that the Pyk2 tyrosine kinase phosphorylates E2 at tyrosine 131, interfering with genome replication. We provide evidence that phosphorylation of E2 prevents binding to the Brd4-CTM. Our findings add to the understanding of molecular pathways utilized by the virus during its vegetative life cycle and offers insights into the host-virus interactome.
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Gilson T, Culleton S, Xie F, DeSmet M, Androphy EJ. Human Papillomavirus 31 Tyrosine 102 Regulates Interaction with E2 Binding Partners and Episomal Maintenance. J Virol 2020; 94:e00590-20. [PMID: 32493825 PMCID: PMC7394896 DOI: 10.1128/jvi.00590-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/17/2020] [Indexed: 12/16/2022] Open
Abstract
Several serine and threonine residues of the papillomavirus early E2 protein have been found to be phosphorylated. In contrast, only one E2 tyrosine phosphorylation site in BPV-1 (tyrosine 102) and one in HPV-16/31 (tyrosine 138) site have been characterized. Between BPV-1 and HPV-31 E2, 8 of the 11 tyrosines are conserved in the N-terminal domain, suggesting that phosphorylation of tyrosines has an essential role in E2 biology. In this study, we examine the effect of Y102 phosphorylation on HPV-31 E2 biology. Y102 proteins mutated either to the potential phospho-mimetic glutamic acid (Y102E) or to the nonphosphorylated homologue phenylalanine (Y102F) remain nuclear; however, Y102E is more associated with the nuclear matrix fraction. This is consistent with the inability of Y102E to bind TopBP1. Both BPV-1 and HPV-31 Y102E are similar in that neither binds the C terminus of Brd4, but in all other aspects the mutant behaves differently between the two families of papillomaviruses. BPV-1 Y102E was unable to bind E1 and did not replicate in a transient in vitro assay, while HPV-31 Y102E binds E1 and was able to replicate, albeit at lower levels than wild type. To examine the effect of E2 mutations under more native-like infection conditions, a neomycin-selectable marker was inserted into L1/L2 of the HPV-31 genome, creating HPV-31neo. This genome was maintained in every cell line tested for at least 50 days posttransfection/infection. Y102E in both transfection and infection conditions was unable to maintain high episome copy numbers in epithelial cell lines.IMPORTANCE Posttranslational modifications by phosphorylation can change protein activities, binding partners, or localization. Tyrosine 102 is conserved between delta papillomavirus BPV-1 and alpha papillomavirus HPV-31 E2. We characterized mutations of HPV-31 E2 for interactions with relevant cellular binding partners and replication in the context of the viral genome.
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Affiliation(s)
- Timra Gilson
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sara Culleton
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Fang Xie
- Department of Dermatology, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Phosphorylation of the Human Papillomavirus E2 Protein at Tyrosine 138 Regulates Episomal Replication. J Virol 2020; 94:JVI.00488-20. [PMID: 32350070 DOI: 10.1128/jvi.00488-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 04/19/2020] [Indexed: 01/15/2023] Open
Abstract
The papillomavirus (PV) E2 protein is a critical regulator of viral transcription and genome replication. We previously reported that tyrosine (Y) 138 of HPV-31 E2 is phosphorylated by the fibroblast growth factor receptor 3 (FGFR3) kinase. In this study, we generated quasiviruses containing G418-selectable HPV-31 genomes with phosphodeficient phenylalanine mutant E2 Y138F and phosphomimetic glutamic acid mutant Y138E. We observed significantly fewer early viral transcripts immediately after infection with these Y138 mutant genomes even though E2 occupancy at the viral origin was equivalent to that of wild-type E2. Keratinocytes infected with Y138F quasiviruses formed stable colonies, and the genomes were maintained as episomes, while those infected with Y138E quasiviruses did not. We previously reported that the HPV-31 E2 Y138 mutation to glutamic acid did not bind to the Brd4 C-terminal motif (CTM). Here, we demonstrate that HPV-16 E2 Y138E bound to full-length Brd4 but not to the Brd4 CTM. We conclude that association of E2 with the Brd4 CTM is necessary for viral genome replication and suggest that this interaction can be regulated by phosphorylation of E2 Y138.IMPORTANCE Papillomavirus (PV) is a double-stranded DNA tumor virus infecting the cutaneous and mucosal epithelium. The PV E2 protein associates with a number of cellular factors to mediate replication of the HPV genome. Fibroblast growth factor receptor 3 (FGFR3) regulates HPV replication through phosphorylation of tyrosine 138 in the HPV E2 protein. Employing a quasivirus infection model and selection for G418 resistant genomes, we demonstrated that Y138 is a critical residue for Brd4 association and that inability to complex with Brd4 does not support episomal replication.
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Phosphorylation of a Conserved Tyrosine in the Papillomavirus E2 Protein Regulates Brd4 Binding and Viral Replication. J Virol 2019; 93:JVI.01801-18. [PMID: 30842331 DOI: 10.1128/jvi.01801-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/02/2019] [Indexed: 02/07/2023] Open
Abstract
The papillomavirus (PV) E2 protein coordinates viral transcription and genome replication. Following a strategy to identify amino acids in E2 that are posttranslationally modified, we reported that tyrosine kinase fibroblast growth factor receptor 3 (FGFR3) complexes with and phosphorylates E2, which inhibits viral DNA replication. Here, we present several lines of evidence indicating that tyrosine (Y) 138 of HPV-31 E2 is a substrate of FGFR3. The active form of FGFR3 bound to and phosphorylated the region of amino acids (aa) 107 to 175 in HPV-31 E2. The E2 phenylalanine (F) mutant Y138F displayed reduced FGFR3-induced phosphotyrosine. A constitutive kinase-active FGFR3 inhibited wild-type (WT) E2-induced E1-dependent DNA replication, while the 138F mutant retained activity. The tyrosine to glutamic acid (E) mutant Y138E, which can mimic phosphotyrosine, failed to induce transient DNA replication, although it maintained the ability to bind and localize the viral DNA helicase E1 to the viral origin. The bromodomain-containing protein 4 (Brd4) binds to E2 and is necessary for initiation of viral DNA synthesis. Interestingly, the Y138E protein coimmunoprecipitated with full-length Brd4 but was defective for association with its C-terminal domain (CTD). These results imply that the activity of the FGFR3 kinase in the infected epithelial cell restricts the HPV replication program through phosphorylation of E2 at Y138, which interferes with E2 binding to the Brd4 CTD, and that this interaction is required for initiation of viral DNA synthesis.IMPORTANCE Human papillomaviruses (HPVs) are highly infectious pathogens that commonly infect the oropharynx and uterine cervix. The idea that posttranslational modifications of viral proteins coordinates viral genome replication is less explored. We recently discovered that fibroblast growth factor receptor 3 (FGFR3) phosphorylates the viral E2 protein. The current study demonstrates that FGFR3 phosphorylates E2 at tyrosine 138, which inhibits association with the C-terminal peptide of Brd4. This study illustrates a novel regulatory mechanism of virus-host interaction and provides insight into the role of Brd4 in viral replication.
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11
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Jose L, Androphy EJ, DeSmet M. Emerging role of FGF receptors in papillomavirus replication. Future Virol 2018. [DOI: 10.2217/fvl-2018-0137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Leny Jose
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Microbiology & Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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DeSmet M, Kanginakudru S, Jose L, Xie F, Gilson T, Androphy EJ. Papillomavirus E2 protein is regulated by specific fibroblast growth factor receptors. Virology 2018; 521:62-68. [PMID: 29885490 DOI: 10.1016/j.virol.2018.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 02/01/2023]
Abstract
The papillomavirus (PV) E2 protein activates transcription and replication by recruiting cellular proteins and the E1 DNA helicase to their binding sites in the viral genome. We recently demonstrated that phosphorylation of tyrosine 102 in the bovine papillomavirus (BPV-1) E2 protein restricts these activities and that fibroblast growth factor receptor-3 (FGFR3) tyrosine kinase binds PV E2. Expression of FGFR3 decreased viral replication with both wild-type and the phenylalanine substitution at position 102, inferring that another kinase targets Y102. Here we tested FGFR- 1, -2 and -4 for association with PV E2 proteins. FGFR2 but not FGFR1 or FGFR4 co-immunoprecipitated with BPV-1 E2. We found that FGFR2 suppressed replication but did not depend on phosphorylation of BPV-1 Y102. HPV-16 and -31 E2 interacted with FGFR1, -2, and -4. These results imply that the expression and activity of FGF receptors in epithelial cells can regulate the function of E2 in viral replication.
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Affiliation(s)
- Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Leny Jose
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Fang Xie
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Dermatology, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Timra Gilson
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA.
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13
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Identification and Functional Characterization of Phosphorylation Sites of the Human Papillomavirus 31 E8^E2 Protein. J Virol 2018; 92:JVI.01743-17. [PMID: 29167339 DOI: 10.1128/jvi.01743-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/15/2017] [Indexed: 12/16/2022] Open
Abstract
The papillomavirus E2 protein regulates transcription, replication, and nuclear retention of viral genomes. Phosphorylation of E2 in the hinge region has been suggested to modulate protein stability, DNA-binding activity, and chromosomal attachment. The papillomavirus E8^E2 protein shares the hinge domain with E2 and acts as a repressor of viral replication. Mass spectrometry analyses of human papillomavirus 31 (HPV31) E8^E2 and E2 proteins identify phosphorylated S78, S81, and S100 in E8^E2 and S266 and S269 in E2 in their hinge regions. Phos-tag analyses of wild-type and mutant proteins indicate that S78 is a major phosphorylation site in E8^E2, but the corresponding S266 in E2 is not. Phosphorylation at S78 regulates E8^E2's repression activity of reporter constructs, whereas the corresponding E2 mutants do not display a phenotype. Phosphorylation at S78 does not alter E8^E2's protein stability, nuclear localization, or binding to DNA or to cellular NCoR/SMRT complexes. Surprisingly, in the context of HPV31 genomes, mutation of E8^E2 S78 does not modulate viral replication or transcription in undifferentiated or differentiated cells. However, comparative transcriptome analyses of differentiated HPV31 E8^E2 S78A and S78E cell lines reveal that the expression of a small number of cellular genes is changed. Validation experiments suggest that the transcription of the cellular LYPD2 gene is altered in a phospho-S78 E8^E2-dependent manner. In summary, our data suggest that phosphorylation of S78 in E8^E2 regulates its repression activity by a novel mechanism, and this seems to be important for the modulation of host cell gene expression but not viral replication.IMPORTANCE Posttranslational modification of viral proteins is a common feature to modulate their activities. Phosphorylation of serine residues S298 and S301 in the hinge region of the bovine papillomavirus type 1 E2 protein has been shown to restrict viral replication. The papillomavirus E8^E2 protein shares the hinge domain with E2 and acts as a repressor of viral replication. A large fraction of HPV31 E8^E2 is phosphorylated at S78 in the hinge region, and this is important for E8^E2's repression activity. Surprisingly, phosphorylation at S78 in E8^E2 has no impact on viral replication in tissue culture but rather seems to modulate the expression of a small number of cellular genes. This may indicate that phosphorylation of viral transcription factors serves to broaden their target gene specificity.
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Kinase Activity of Fibroblast Growth Factor Receptor 3 Regulates Activity of the Papillomavirus E2 Protein. J Virol 2017; 91:JVI.01066-17. [PMID: 28768864 DOI: 10.1128/jvi.01066-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 07/26/2017] [Indexed: 01/02/2023] Open
Abstract
The papillomavirus (PV) E2 protein is a DNA binding, protein interaction platform that recruits viral and host factors necessary for transcription and replication. We recently discovered phosphorylation of a tyrosine (Y102) in bovine PV (BPV) E2. To identify the responsible factor, we tested several candidate tyrosine kinases that are highly expressed in keratinocytes for binding to BPV-1 E2. Fibroblast growth factor receptor 3 (FGFR3) coimmunoprecipitated with the BPV-1 E2 protein, as did human papillomavirus 31 (HPV-31) E2, which also colocalized with FGFR3 within the nucleus. A constitutively active mutant form of FGFR3 decreased BPV-1 and HPV-31 transient replication although this result also occurred in a BPV-1 E2 mutant lacking a previously identified phosphorylation site of interest (Y102). Furthermore, FGFR3 depletion in cell lines that maintain HPV-31 episomes increased viral copy number. These results suggest that FGFR3 kinase activity may regulate the PV reproductive program through phosphorylation of the E2 protein although this is unlikely to occur through the Y102 residue of HPV E2.IMPORTANCE The papillomavirus (PV) is a double-stranded DNA tumor virus infecting cervix, mouth, and throat tissues. The viral protein E2 is responsible for the replication of the virus. Understanding the mechanisms of the replicative life cycle of the virus may bring to light direct targets and treatments against viral infection. We recently found that the fibroblast growth factor receptor 3 (FGFR3) interacts with and mediates PV E2 function through phosphorylation of the E2 protein. Our study suggests that the function of the E2 protein may be regulated through a direct FGFR3 target during the maintenance stage of the PV life cycle.
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