scholarly journals A unique insert in the genomes of high-risk human papillomaviruses with a predicted dual role in conferring oncogenic risk

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1000 ◽  
Author(s):  
Noam Auslander ◽  
Yuri I. Wolf ◽  
Svetlana A. Shabalina ◽  
Eugene V. Koonin
Keyword(s):  
High Risk ◽  
Pdz Domain ◽  
Human Papillomaviruses ◽  
Machine Learning Techniques ◽  
Genome Comparison ◽  
Binding Motif ◽  
E6 Oncoprotein ◽  
C Terminus ◽  
Tumorigenic Potential ◽  
E6 And E7

The differences between high risk and low risk human papillomaviruses (HR-HPV and LR-HPV, respectively) that contribute to the tumorigenic potential of HR-HPV are not well understood but can be expected to involve the HPV oncoproteins, E6 and E7. We combine genome comparison and machine learning techniques to identify a previously unnoticed insert near the 3’-end of the E6 oncoprotein gene that is unique to HR-HPV. Analysis of the insert sequence suggests that it exerts a dual effect, by creating a PDZ domain-binding motif at the C-terminus of E6, as well as eliminating the overlap between the E6 and E7 coding regions in HR-HPV. We show that, as a result, the insert might enable coupled termination-reinitiation of the E6 and E7 genes, supported by motifs complementary to the human 18S rRNA. We hypothesize that the added functionality of E6 and positive regulation of E7 expression jointly account for the tumorigenic potential of HR-HPV.

scholarly journals A unique insert in the genomes of high-risk human papillomaviruses with a predicted dual role in conferring oncogenic risk

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1000 ◽  
Author(s):  
Noam Auslander ◽  
Yuri I. Wolf ◽  
Svetlana A. Shabalina ◽  
Eugene V. Koonin
Keyword(s):  
High Risk ◽  
Pdz Domain ◽  
Human Papillomaviruses ◽  
Machine Learning Techniques ◽  
Genome Comparison ◽  
Binding Motif ◽  
E6 Oncoprotein ◽  
C Terminus ◽  
Tumorigenic Potential ◽  
E6 And E7

The differences between high risk and low risk human papillomaviruses (HR-HPV and LR-HPV, respectively) that contribute to the tumorigenic potential of HR-HPV are not well understood but can be expected to involve the HPV oncoproteins, E6 and E7. We combine genome comparison and machine learning techniques to identify a previously unnoticed insert near the 3’-end of the E6 oncoprotein gene that is unique to HR-HPV. Analysis of the insert sequence suggests that it exerts a dual effect, by creating a PDZ domain-binding motif at the C-terminus of E6 as well as eliminating the overlap between the E6 and E7 coding regions in HR-HPV. We show that as a result, the insert might enable coupled termination-reinitiation of the E6 and E7 genes, supported by motifs complementary to the human 18S rRNA. We hypothesize that the added functionality of E6 and positive regulation of E7 expression jointly account for the tumorigenic potential of HR-HPV.

scholarly journals Multi-PDZ Domain Protein MUPP1 Is a Cellular Target for both Adenovirus E4-ORF1 and High-Risk Papillomavirus Type 18 E6 Oncoproteins

2000 ◽  
Vol 74 (20) ◽  
pp. 9680-9693 ◽  
Author(s):  
Siu Sylvia Lee ◽  
Britt Glaunsinger ◽  
Fiamma Mantovani ◽  
Lawrence Banks ◽  
Ronald T. Javier
Keyword(s):  
High Risk ◽  
Cellular Proliferation ◽  
Pdz Domain ◽  
Viral Proteins ◽  
Cellular Protein ◽  
Human Papillomaviruses ◽  
Binding Motif ◽  
Cellular Factor ◽  
Domain Protein ◽  
Hpv 18

ABSTRACT A general theme that has emerged from studies of DNA tumor viruses is that otherwise unrelated oncoproteins encoded by these viruses often target the same important cellular factors. Major oncogenic determinants for human adenovirus type 9 (Ad9) and high-risk human papillomaviruses (HPV) are the E4-ORF1 and E6 oncoproteins, respectively, and although otherwise unrelated, both of these viral proteins possess a functional PDZ domain-binding motif that is essential for their transforming activity and for binding to the PDZ domain-containing and putative tumor suppressor protein DLG. We report here that the PDZ domain-binding motifs of Ad9 E4-ORF1 and high-risk HPV-18 E6 also mediate binding to the widely expressed cellular factor MUPP1, a large multi-PDZ domain protein predicted to function as an adapter in signal transduction. With regard to the consequences of these interactions in cells, we showed that Ad9 E4-ORF1 aberrantly sequesters MUPP1 within the cytoplasm of cells whereas HPV-18 E6 targets this cellular protein for degradation. These effects were specific because mutant viral proteins unable to bind MUPP1 lack these activities. From these results, we propose that the multi-PDZ domain protein MUPP1 is involved in negatively regulating cellular proliferation and that the transforming activities of two different viral oncoproteins depend, in part, on their ability to inactivate this cellular factor.

scholarly journals Recognition of high-risk HPV E6 oncoproteins by 14-3-3 proteins studied by interactomics and crystallography

2020 ◽  
Author(s):  
Gergo Gogl ◽  
Kristina V. Tugaeva ◽  
Pascal Eberling ◽  
Camille Kostmann ◽  
Gilles Trave ◽  
...  
Keyword(s):  
High Risk ◽  
Fluorescence Polarization ◽  
Pdz Domain ◽  
Human Papillomaviruses ◽  
Binding Motif ◽  
Hpv E6 ◽  
Sequence Variations ◽  
Hpv18 E6 ◽  
Isoform Specificity ◽  
High Risk Hpv

AbstractIn tumors induced by high-risk mucosal human papillomaviruses (hrm-HPVs), HPV E6 oncoproteins inhibit apoptotic processes and sustain cell proliferation. E6 from all hrm-HPVs harbor a C-terminal short PDZ domain-binding motif (PBM), whose phosphorylation down-regulates PDZ binding but triggers E6 binding to 14-3-3 proteins. Here we classify PBMs of E6 proteins depending on their principle ability to be phosphorylated and subsequently acquire a 14-3-3-binding motif III consensus, (pS/pT)XX-COOH. Systematic competitive fluorescence polarization measurements show that the PBMs from four selected E6 oncoproteins bind all seven human 14-3-3 isoforms with distinct, wide-ranging affinities, obeying remarkable trends assigned to 14-3-3 isoform specificity and small E6 sequence variations. We crystallized the hrm-HPV18 E6 PBM bound to 14-3-3ζ, revealing a 14-3-3-motif III complex at 1.9 Å resolution. Using fluorescence polarization and crystallography, we also demonstrate that fusicoccin, a molecule that reinforces many known 14-3-3 complexes, destabilizes the 14-3-3-E6 interaction, indicating the druggability of that complex.

scholarly journals Protein tyrosine phosphatase H1 is a target of the E6 oncoprotein of high-risk genital human papillomaviruses

2007 ◽  
Vol 88 (11) ◽  
pp. 2956-2965 ◽  
Author(s):  
Stephanie Töpffer ◽  
Andreas Müller-Schiffmann ◽  
Konstantin Matentzoglu ◽  
Martin Scheffner ◽  
Gertrud Steger
Keyword(s):  
High Risk ◽  
Cervical Carcinoma ◽  
Protein Tyrosine Phosphatase ◽  
Carcinoma Cell ◽  
Tyrosine Phosphatase ◽  
Pdz Domain ◽  
Human Papillomaviruses ◽  
Binding Motif ◽  
Protein Tyrosine ◽  
Pdz Domain Proteins

The E6 proteins of high-risk genital human papillomaviruses (HPV), such as HPV types 16 and 18, possess a conserved C-terminal PDZ-binding motif, which mediates interaction with some cellular PDZ domain proteins. The binding of E6 usually results in their ubiquitin-mediated degradation. The ability of E6 to bind to PDZ domain proteins correlates with the oncogenic potential. Using a yeast two-hybrid system, GST pull-down experiments and coimmunoprecipitations, we identified the protein tyrosine phosphatase H1 (PTPH1/PTPN3) as a novel target of the PDZ-binding motif of E6 of HPV16 and 18. PTPH1 has been suggested to function as tumour suppressor protein, since mutational analysis revealed somatic mutations in PTPH1 in a minor fraction of various human tumours. We show here that HPV16 E6 accelerated the proteasome-mediated degradation of PTPH1, which required the binding of E6 to the cellular ubiquitin ligase E6-AP and to PTPH1. The endogenous levels of PTPH1 were particularly low in HPV-positive cervical carcinoma cell lines. The reintroduction of the E2 protein into the HPV16-positive cervical carcinoma cell line SiHa, known to lead to a sharp repression of E6 expression and to induce growth suppression, resulted in an increase of the amount of PTPH1. Our data suggest that reducing the level of PTPH1 may contribute to the oncogenic activity of high-risk genital E6 proteins.

scholarly journals Recognition of high-risk HPV E6 oncoproteins by 14-3-3 proteins studied by interactomics and crystallography

2020 ◽  
Author(s):  
Gergő Gógl ◽  
Kristina Tugaeva ◽  
Pascal Eberling ◽  
Camille Kostmann ◽  
Gilles Trave ◽  
...  
Keyword(s):  
High Risk ◽  
Fluorescence Polarization ◽  
Pdz Domain ◽  
Human Papillomaviruses ◽  
Binding Motif ◽  
Hpv E6 ◽  
Sequence Variations ◽  
Hpv18 E6 ◽  
Isoform Specificity ◽  
High Risk Hpv

Abstract In tumors induced by high-risk mucosal human papillomaviruses (hrm-HPVs), HPV E6 oncoproteins inhibit apoptotic processes and sustain cell proliferation. E6 from all hrm-HPVs harbor a C-terminal short PDZ domain-binding motif (PBM), whose phosphorylation down-regulates PDZ binding but triggers E6 binding to 14-3-3 proteins. Here we classify PBMs of E6 proteins depending on their principle ability to be phosphorylated and subsequently acquire a 14-3-3-binding motif III consensus, (pS/pT)XX-COOH. Systematic competitive fluorescence polarization measurements show that the PBMs from four selected E6 oncoproteins bind all seven human 14-3-3 isoforms with distinct, wide-ranging affinities, obeying remarkable trends assigned to 14-3-3 isoform specificity and small E6 sequence variations. We crystallized the hrm-HPV18 E6 PBM bound to 14-3-3ζ, revealing a 14-3-3-motif III complex at 1.9 Å resolution. Using fluorescence polarization and crystallography, we also demonstrate that fusicoccin, a molecule that reinforces many known 14-3-3 complexes, destabilizes the 14-3-3-E6 interaction, indicating the druggability of that complex.

scholarly journals Role of the PDZ Domain-Binding Motif of the Oncoprotein E6 in the Pathogenesis of Human Papillomavirus Type 31

2004 ◽  
Vol 78 (22) ◽  
pp. 12366-12377 ◽  
Author(s):  
Choongho Lee ◽  
Laimonis A. Laimins
Keyword(s):  
High Risk ◽  
Pdz Domain ◽  
Immunohistochemical Analysis ◽  
Human Papillomaviruses ◽  
Binding Motif ◽  
Wild Type ◽  
Pdz Proteins ◽  
Viral Copy Number ◽  
Viral Copy

ABSTRACT A number of PDZ domain-containing proteins have been identified as binding partners for the oncoprotein E6 of the high-risk type human papillomaviruses (HPVs). These include hDlg, hScrib, MAGI-1, MAGI-2, MAGI-3, and MUPP1. The PDZ domain-binding motif (-X-T-X-V) at the carboxy terminus of E6 is essential for targeting PDZ proteins for proteasomal degradation. The presence of this motif only in the high-risk HPVs suggests its possible role in HPV-induced oncogenesis. To investigate the role of the PDZ domain-binding motif of E6 in the HPV life cycle, two mutant HPV31 genomes were constructed: E6ValΔ, with a deletion of the last amino acid residue of E6 (valine), and E6ETQVΔ, with a deletion of the entire PDZ domain-binding motif of E6 (ETQV). Three human foreskin keratinocyte (HFK) cell lines were established which maintained transfected wild-type HPV31 or either of two mutant genomes. Cells containing either of two mutant genomes were significantly retarded in their growth rates and reduced in their viral copy numbers compared to those transfected with wild-type genomes. Western analysis did not reveal any significant changes in the levels of PDZ proteins following stable transfection of any HPV31 genomes into HFKs. Although the E6ETQVΔ-transfected HFKs exhibited a pattern of morphological differentiation that appeared different from the HPV31 wild-type-transfected HFKs in organotypic raft cultures, immunohistochemical analysis failed to identify substantial changes in the differentiation-dependent membrane localization of hDlg proteins. These results suggest that binding of E6 to PDZ proteins modulates the early viral functions such as proliferation and maintenance of the viral copy number in undifferentiated cells.

scholarly journals Human Papillomavirus Type 16 E6 induces cell competition

2021 ◽  
Author(s):  
Nicole Brimer ◽  
Scott Vande Pol
Keyword(s):  
Human Papillomavirus ◽  
High Risk ◽  
Epithelial Cells ◽  
Human Papillomaviruses ◽  
Cell Competition ◽  
Vitro Assay ◽  
Epithelial Tumors ◽  
E6 Oncoprotein ◽  
E6 And E7

High risk human papillomavirus (HPV) infections induce squamous epithelial tumors in which the virus replicates.  Initially, the virus-infected epithelial cells are untransformed, but expand in both number and area at the expense of normal squamous epithelial cells.  How this occurs is unknown, but is presumed to be due to viral oncogene expression.  We have developed an  in vitro  assay in which colonies of post-confluent HPV16 expressing cells outcompete confluent surrounding normal keratinocytes for surface area.   The enhanced cell competition induced by the complete HPV16 genome is conferred by E6 expression alone, and not by individual expression of E5 or E7.   In traditional oncogene assays, E7 is a more potent oncogene than E6, but such assays do not include interaction with normal surrounding cells.  These new results separate classic oncogenicity that is primarily conferred by E7, from cell competition that we show is primarily conferred by E6, and provides a new biological role for E6 oncoproteins from high risk human papillomaviruses.   Importance High risk papillomavirus infections induce epithelial tumors, some of which evolve into malignancies.   The development and maintenance of cancer is due to the virally encoded E6 and E7 oncoproteins.  How a virally infected keratinocyte out-competes normal uninfected keratinocytes has been unknown.  The present work shows that the enhanced competition of HPV16-infected cells is primarily due to the expression of the E6 oncoprotein and not the E7 or E5 oncoproteins.   This work shows the importance of measuring oncoprotein traits in the context of cell competition with uninfected cells, and shows the potential of papillomavirus oncoproteins to be novel genetic probes for the analysis of cell competition

scholarly journals E6AP-Dependent Degradation of DLG4/PSD95 by High-Risk Human Papillomavirus Type 18 E6 Protein

2006 ◽  
Vol 81 (3) ◽  
pp. 1379-1389 ◽  
Author(s):  
Keisuke Handa ◽  
Takashi Yugawa ◽  
Mako Narisawa-Saito ◽  
Shin-ichi Ohno ◽  
Masatoshi Fujita ◽  
...  
Keyword(s):  
High Risk ◽  
Tumor Suppressor ◽  
Pdz Domain ◽  
Mouse Skin ◽  
Human Papillomaviruses ◽  
Binding Motif ◽  
Human Homologue ◽  
Large Tumor ◽  
Hpv16 E6 ◽  
Carboxy Terminal

ABSTRACT In most cervical cancers, DNAs of high-risk mucosotropic human papillomaviruses (HPVs), such as types 16 and 18, are maintained so as to express two viral proteins, E6 and E7, suggesting that they play important roles in carcinogenesis. The carboxy-terminal PDZ domain-binding motif of the E6 proteins is in fact essential for transformation of rodent cells and induction of hyperplasia in E6-transgenic mouse skin. To date, seven PDZ domain-containing proteins, including DLG1/hDLG, which is a human homologue of the Drosophila discs large tumor suppressor (Dlg), have been identified as targets of high-risk HPV E6 proteins. Here, we describe DLG4/PSD95, another human homologue of Dlg, as a novel E6 target. DLG4 was found to be expressed in normal human cells, including cervical keratinocytes, but only to a limited extent in both HPV-positive and HPV-negative cervical cancer cell lines. Expression of HPV18 E6 in HCK1T decreased DLG4 levels more strongly than did HPV16 E6, the carboxy-terminal motif of the proteins being critical for binding and degradation of DLG4 in vitro. DLG4 levels were restored by expression of either E6AP-specific short hairpin RNA or bovine papillomavirus type 1 E2 in HeLa but not CaSki or SiHa cells, reflecting downregulation of DLG4 mRNA as opposed to protein by an HPV-independent mechanism in HPV16-positive cancer lines. The tumorigenicity of CaSki cells was strongly inhibited by forced expression of DLG4, while growth in culture was not inhibited at all. These results suggest that DLG4 may function as a tumor suppressor in the development of HPV-associated cancers.

scholarly journals MARCKS domain phosphorylation regulates the differential interaction of Diacylglycerol Kinase ζ with Rac1, RhoA and Syntrophin

2020 ◽  
Author(s):  
Ryan Ard ◽  
Jean-Christian Maillet ◽  
Elias Daher ◽  
Michael Phan ◽  
Radoslav Zinoviev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Mechanisms ◽  
Rho Gtpase ◽  
Pdz Domain ◽  
Diacylglycerol Kinase ◽  
Binding Motif ◽  
Membrane Blebbing ◽  
Rhoa Activity ◽  
C Terminus ◽  
Mechanistic Basis

AbstractCells can switch between Rac1, lamellipodia-based and RhoA, blebbing-based migration modes but the molecular mechanisms regulating this choice are not fully understood. Diacylglycerol kinase ζ (DGKζ), which phosphorylates diacylglycerol to yield phosphatidic acid, forms independent complexes with Rac1 and RhoA, selectively dissociating each from RhoGDI. DGKζ catalytic activity is required for Rac1 dissociation but is dispensable for RhoA dissociation. Instead, DGKζ functions as a scaffold that stimulates RhoA release by enhancing RhoGDI phosphorylation by protein kinase Cα (PKCα). Here, PKCα-mediated phosphorylation of the DGKζ MARCKS domain increased DGKζ association with RhoA and decreased its interaction with Rac1. The same modification increased binding of the DGKζ C-terminus to the α1-syntrophin PDZ domain. Expression of a phosphomimetic DGKζ mutant stimulated membrane blebbing in mouse embryonic fibroblasts and C2C12 myoblasts, which was augmented by inhibition of endogenous Rac1. DGKζ expression in differentiated C2 myotubes, which have low endogenous Rac1 levels, also induced substantial membrane blebbing via the Rho-ROCK pathway. These events were independent of DGKζ catalytic activity, but dependent upon a functional C-terminal PDZ-binding motif. Rescue of RhoA activity in DGKζ-null cells required the PDZ-binding motif, suggesting syntrophin interaction is necessary for optimal RhoA activation. Collectively, our results define a switch-like mechanism involving DGKζ phosphorylation by PKCα that favours RhoA-driven blebbing over Rac1-driven lamellipodia formation and macropinocytosis. These findings provide a mechanistic basis for the effect of PKCα signaling on Rho GTPase activity and suggest PKCα activity plays a role in the interconversion between Rac1 and RhoA signaling that underlies different migration modes.

scholarly journals The E6 Oncoproteins of High-Risk Papillomaviruses Bind to a Novel Putative GAP Protein, E6TP1, and Target It for Degradation

1999 ◽  
Vol 19 (1) ◽  
pp. 733-744 ◽  
Author(s):  
Qingshen Gao ◽  
Seetha Srinivasan ◽  
Sarah N. Boyer ◽  
David E. Wazer ◽  
Vimla Band
Keyword(s):  
High Risk ◽  
P53 Protein ◽  
Single Gene ◽  
Human Papillomaviruses ◽  
Dominant Negative ◽  
Hpv16 E6 ◽  
Hpv E6 ◽  
E6 Oncoprotein ◽  
E6 Protein

ABSTRACT The high-risk human papillomaviruses (HPVs) are associated with carcinomas of the cervix and other genital tumors. Previous studies have identified two viral oncoproteins, E6 and E7, which are expressed in the majority of HPV-associated carcinomas. The ability of high-risk HPV E6 protein to immortalize human mammary epithelial cells (MECs) has provided a single-gene model to study the mechanisms of E6-induced oncogenic transformation. In this system, the E6 protein targets the p53 tumor suppressor protein for degradation, and mutational analyses have shown that E6-induced degradation of p53 protein is required for MEC immortalization. However, the inability of most dominant-negative p53 mutants to induce efficient immortalization of MECs suggests the existence of additional targets of the HPV E6 oncoprotein. Using the yeast two-hybrid system, we have isolated a novel E6-binding protein. This polypeptide, designated E6TP1 (E6-targeted protein 1), exhibits high homology to GTPase-activating proteins for Rap, including SPA-1, tuberin, and Rap1GAP. The mRNA for E6TP1 is widely expressed in tissues and in vitro-cultured cell lines. The gene for E6TP1 localizes to chromosome 14q23.2-14q24.3 within a locus that has been shown to undergo loss of heterozygosity in malignant meningiomas. Importantly, E6TP1 is targeted for degradation by the high-risk but not the low-risk HPV E6 proteins both in vitro and in vivo. Furthermore, the immortalization-competent but not the immortalization-incompetent HPV16 E6 mutants target the E6TP1 protein for degradation. Our results identify a novel target for the E6 oncoprotein and provide a potential link between HPV E6 oncogenesis and alteration of a small G protein signaling pathway.

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