1
|
Suryajaya W, Biswas T, Shahabi S, Mealka M, Huxford T, Ghosh G. HDX-MS Analysis of Catalytic Activation of IKK2 in the IκB Kinase Complex. Biochemistry 2024. [PMID: 39185716 DOI: 10.1021/acs.biochem.4c00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
The IκB Kinase (IKK) complex, containing catalytic IKK2 and noncatalytic NEMO subunits, plays essential roles in the induction of transcription factors of the NF-κB family. Catalytic activation of IKK2 via phosphorylation of its activation loop is promoted upon noncovalent association of linear or K63-linked polyubiquitin chains to NEMO within the IKK complex. The mechanisms of this activation remain speculative. To investigate interaction dynamics within the IKK complex during activation of IKK2, we conducted hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS) on NEMO and IKK2 proteins in their free and complex-bound states. Altered proton exchange profiles were observed in both IKK2 and NEMO upon complex formation, and changes were consistent with the involvement of distinct regions throughout the entire length of both proteins, including previously uncharacterized segments, in direct or allosteric interactions. Association with linear tetraubiquitin (Ub4) affected multiple regions of the IKK2:NEMO complex, in addition to previously identified interaction sites on NEMO. Intriguingly, observed enhanced solvent accessibility of the IKK2 activation loop within the IKK2:NEMO:Ub4 complex, coupled with contrasting protection of surrounding segments of the catalytic subunit, suggests an allosteric role for NEMO:Ub4 in priming IKK2 for phosphorylation-dependent catalytic activation.
Collapse
Affiliation(s)
- William Suryajaya
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| | - Tapan Biswas
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| | - Shandy Shahabi
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| | - Matthew Mealka
- Structural Biochemistry Laboratory Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, United States
| | - Tom Huxford
- Structural Biochemistry Laboratory Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, United States
| | - Gourisankar Ghosh
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| |
Collapse
|
2
|
Meyniel-Schicklin L, Amaudrut J, Mallinjoud P, Guillier F, Mangeot PE, Lines L, Aublin-Gex A, Scholtes C, Punginelli C, Joly S, Vasseur F, Manet E, Gruffat H, Henry T, Halitim F, Paparin JL, Machin P, Darteil R, Sampson D, Mikaelian I, Lane L, Navratil V, Golinelli-Cohen MP, Terzi F, André P, Lotteau V, Vonderscher J, Meldrum EC, de Chassey B. Viruses traverse the human proteome through peptide interfaces that can be biomimetically leveraged for drug discovery. Proc Natl Acad Sci U S A 2024; 121:e2308776121. [PMID: 38252831 PMCID: PMC10835127 DOI: 10.1073/pnas.2308776121] [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: 06/16/2023] [Accepted: 12/06/2023] [Indexed: 01/24/2024] Open
Abstract
We present a drug design strategy based on structural knowledge of protein-protein interfaces selected through virus-host coevolution and translated into highly potential small molecules. This approach is grounded on Vinland, the most comprehensive atlas of virus-human protein-protein interactions with annotation of interacting domains. From this inspiration, we identified small viral protein domains responsible for interaction with human proteins. These peptides form a library of new chemical entities used to screen for replication modulators of several pathogens. As a proof of concept, a peptide from a KSHV protein, identified as an inhibitor of influenza virus replication, was translated into a small molecule series with low nanomolar antiviral activity. By targeting the NEET proteins, these molecules turn out to be of therapeutic interest in a nonalcoholic steatohepatitis mouse model with kidney lesions. This study provides a biomimetic framework to design original chemistries targeting cellular proteins, with indications going far beyond infectious diseases.
Collapse
Affiliation(s)
| | | | | | | | - Philippe E. Mangeot
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | | | - Anne Aublin-Gex
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | - Caroline Scholtes
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | - Claire Punginelli
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | | | - Florence Vasseur
- Université de Paris, INSERM U1151, CNRS UMR 8253, Institut Necker Enfants Malades, Département “Croissance et Signalisation”, Paris75015, France
| | - Evelyne Manet
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | - Henri Gruffat
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | - Thomas Henry
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | | | | | | | | | | | - Ivan Mikaelian
- Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de recherche en cancérologie de Lyon, Lyon69373, France
| | - Lydie Lane
- Computer and Laboratory Investigation of Proteins of Human Origin Group, Swiss Institute of Bioinformatics, Lausanne1015, Switzerland
| | - Vincent Navratil
- Pôle Rhône-Alpes de bioinformatique, Rhône-Alpes Bioinformatics Center, Université Lyon 1, Villeurbanne69622, France
- European Virus Bio-informatiques Center, Jena07743, Germany
- Institut Français de Bioinformatique, IFB-core, UMS 3601, Évry91057, France
| | - Marie-Pierre Golinelli-Cohen
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, Unité Propre de Recherche 2301, Gif-sur-Yvette91198, France
| | - Fabiola Terzi
- Université de Paris, INSERM U1151, CNRS UMR 8253, Institut Necker Enfants Malades, Département “Croissance et Signalisation”, Paris75015, France
| | - Patrice André
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | - Vincent Lotteau
- Centre International de Recherche en Infectiologie, University Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Lyon69007, France
| | | | | | | |
Collapse
|
3
|
Santacroce L, Magrone T. Molluscum Contagiosum Virus: Biology and Immune Response. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1451:151-170. [PMID: 38801577 DOI: 10.1007/978-3-031-57165-7_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Molluscum contagiosum virus is a poxvirus belonging to the Poxviridae family, which includes Orthopoxvirus, Parapoxvirus, Yantapoxvirus, Molluscipoxvirus, Smallpox virus, Cowpox virus and Monkeypox virus. MCV belongs to the genus Molluscipoxvirus and has a tropism for skin tissue. MCV infects keratinocytes and, after an incubation period of 2 weeks to 6 weeks, causes a breakdown of the skin barrier with the development of papules of variable size depending on the proper functioning of the immune response (both adaptive and acquired). MCV only infects humans and does not cause viraemia. MCV encodes for several inhibitory proteins responsible to circumvent the immune response through different signalling pathways. Individuals who can be infected with MCV are children, immunocompromised individuals such as organ transplant recipients and Human Immunodeficiency Virus (HIV)-infected individuals. Current treatments to manage MCV-induced lesions are different and include the use of immunomodulators, which, however, do not provide an effective response.
Collapse
Affiliation(s)
- Luigi Santacroce
- Section of Microbiology and Virology, Interdisciplinary Department of Medicine, School of Medicine, University of Bari, Bari, Italy.
| | - Thea Magrone
- Section of Microbiology and Virology, Interdisciplinary Department of Medicine, School of Medicine, University of Bari, Bari, Italy
| |
Collapse
|
4
|
DiRusso CJ, DeMaria AM, Wong J, Wang W, Jordanides JJ, Whitty A, Allen KN, Gilmore TD. A conserved core region of the scaffold NEMO is essential for signal-induced conformational change and liquid-liquid phase separation. J Biol Chem 2023; 299:105396. [PMID: 37890781 PMCID: PMC10694592 DOI: 10.1016/j.jbc.2023.105396] [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: 05/23/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Scaffold proteins help mediate interactions between protein partners, often to optimize intracellular signaling. Herein, we use comparative, biochemical, biophysical, molecular, and cellular approaches to investigate how the scaffold protein NEMO contributes to signaling in the NF-κB pathway. Comparison of NEMO and the related protein optineurin from a variety of evolutionarily distant organisms revealed that a central region of NEMO, called the Intervening Domain (IVD), is conserved between NEMO and optineurin. Previous studies have shown that this central core region of the IVD is required for cytokine-induced activation of IκB kinase (IKK). We show that the analogous region of optineurin can functionally replace the core region of the NEMO IVD. We also show that an intact IVD is required for the formation of disulfide-bonded dimers of NEMO. Moreover, inactivating mutations in this core region abrogate the ability of NEMO to form ubiquitin-induced liquid-liquid phase separation droplets in vitro and signal-induced puncta in vivo. Thermal and chemical denaturation studies of truncated NEMO variants indicate that the IVD, while not intrinsically destabilizing, can reduce the stability of surrounding regions of NEMO due to the conflicting structural demands imparted on this region by flanking upstream and downstream domains. This conformational strain in the IVD mediates allosteric communication between the N- and C-terminal regions of NEMO. Overall, these results support a model in which the IVD of NEMO participates in signal-induced activation of the IKK/NF-κB pathway by acting as a mediator of conformational changes in NEMO.
Collapse
Affiliation(s)
| | - Anthony M DeMaria
- Department of Chemistry, Boston University, Boston, Massachusetts, USA
| | - Judy Wong
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Wei Wang
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Jack J Jordanides
- Department of Chemistry, Boston University, Boston, Massachusetts, USA
| | - Adrian Whitty
- Department of Chemistry, Boston University, Boston, Massachusetts, USA
| | - Karen N Allen
- Department of Chemistry, Boston University, Boston, Massachusetts, USA.
| | - Thomas D Gilmore
- Department of Biology, Boston University, Boston, Massachusetts, USA.
| |
Collapse
|
5
|
DiRusso CJ, DeMaria AM, Wong J, Jordanides JJ, Whitty A, Allen KN, Gilmore TD. A Conserved Core Region of the Scaffold NEMO is Essential for Signal-induced Conformational Change and Liquid-liquid Phase Separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.25.542299. [PMID: 37292615 PMCID: PMC10245932 DOI: 10.1101/2023.05.25.542299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Scaffold proteins help mediate interactions between protein partners, often to optimize intracellular signaling. Herein, we use comparative, biochemical, biophysical, molecular, and cellular approaches to investigate how the scaffold protein NEMO contributes to signaling in the NF-κB pathway. Comparison of NEMO and the related protein optineurin from a variety of evolutionarily distant organisms revealed that a central region of NEMO, called the Intervening Domain (IVD), is conserved between NEMO and optineurin. Previous studies have shown that this central core region of the IVD is required for cytokine-induced activation of IκB kinase (IKK). We show that the analogous region of optineurin can functionally replace the core region of the NEMO IVD. We also show that an intact IVD is required for the formation of disulfide-bonded dimers of NEMO. Moreover, inactivating mutations in this core region abrogate the ability of NEMO to form ubiquitin-induced liquid-liquid phase separation droplets in vitro and signal-induced puncta in vivo. Thermal and chemical denaturation studies of truncated NEMO variants indicate that the IVD, while not intrinsically destabilizing, can reduce the stability of surrounding regions of NEMO, due to the conflicting structural demands imparted on this region by flanking upstream and downstream domains. This conformational strain in the IVD mediates allosteric communication between N- and C-terminal regions of NEMO. Overall, these results support a model in which the IVD of NEMO participates in signal-induced activation of the IKK/NF-κB pathway by acting as a mediator of conformational changes in NEMO.
Collapse
Affiliation(s)
| | | | - Judy Wong
- Department of Biology, Boston University, Boston, MA 02215, USA
| | | | - Adrian Whitty
- Department of Chemistry, Boston University, Boston, MA 02215, USA
| | - Karen N. Allen
- Department of Chemistry, Boston University, Boston, MA 02215, USA
| | | |
Collapse
|
6
|
Tan Q, Yao CL. NEMO involves in NF-κB activation by interaction with p65 and promoting its nuclear translocation in large yellow croaker (Larimichthys crocea). FISH & SHELLFISH IMMUNOLOGY 2023; 134:108637. [PMID: 36841517 DOI: 10.1016/j.fsi.2023.108637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/10/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
NEMO (nuclear factor-κB <NF-κB> essential modulator) plays an important role in activating NF-κB signaling pathway, p65 is a pivotal positive-regulator of NF-κB family. However, the role of NEMO in p65-triggered immune activation in teleost is largely unknown. In the present study, the cDNA sequence of LcNEMO was identified from the large yellow croaker (Larimichthys crocea). The predicated LcNEMO protein encoded 565 amino acids, consisting of a N-terminal NEMO domain, followed by two coiled coil (CC) motifs, a CC2-leucine zipper (CC2-LZ) domain, and a C-terminal zinc finger (ZnF) domain. Quantitative PCR showed that the strongest constitutive expression of LcNEMO was detected in blood and the inductive expression of it significantly enhanced after LPS and poly I:C challenge. The effect of LcNEMO on p65, RelB and cRel associated-immune activation detected by dual-luciferase reporter system assay indicated that Lcp65-triggered NF-κB, TNF-α and IL-1β activation could be significantly enhanced by LcNEMO. Furthermore, Co-IP revealed that the protein-protein interaction was existed between LcNEMO and Lcp65. Western blot and confocal microscope observation displayed that Lcp65 nuclear translocation could be promoted by LcNEMO with a dose- and time-dependent manner, which was further verified by RNA interference of LcNEMO expression. Our findings suggest that LcNEMO may be crucial in immune response by promoting p65-mediated immune activation.
Collapse
Affiliation(s)
- Qing Tan
- Fisheries College, Jimei University, Xiamen, 361021, PR China
| | - Cui-Luan Yao
- Fisheries College, Jimei University, Xiamen, 361021, PR China.
| |
Collapse
|
7
|
Li H, Li L, Qiu X, Zhang J, Hua Z. The interaction of CFLAR with p130Cas promotes cell migration. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119390. [PMID: 36400248 DOI: 10.1016/j.bbamcr.2022.119390] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/27/2022] [Accepted: 11/07/2022] [Indexed: 11/17/2022]
Abstract
CASP8 and FADD Like Apoptosis Regulator (CFLAR) is a key anti-apoptotic regulator for resistance to apoptosis mediated by Fas and TRAIL. In addition to its anti-apoptotic function, CFLAR is also an important mediator of tumor growth. High level of CFLAR expression correlates with a more aggressive tumor. However, the mechanism of CFLAR signaling in malignant progression is not clear. Here we report a novel CFLAR-associated protein p130Cas, which is a general regulator of cell growth and cell migration. CFLAR-p130Cas association is mediated by the DED domain of CFLAR and the SD domain of p130Cas. Immunofluorescence observation showed that CFLAR had the colocalization with p130Cas at the focal adhesion of cell membrane. CFLAR overexpression promoted p130Cas phosphorylation and the formation of focal adhesion complex. Moreover, the enhancement of cell migration induced by CFLAR overexpression was obviously inhibited by p130Cas siRNA. In silico analysis on human database suggests high expressions of CFLAR or/and p130Cas are associated with poor prognosis of patients with lung cancer. Together, our results suggest a new mechanism for CFLAR involved in tumor development via association with p130Cas.
Collapse
Affiliation(s)
- Hao Li
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Luqi Li
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xun Qiu
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jing Zhang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.
| | - Zichun Hua
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China; School of Biopharmacy, China Pharmaceutical University, Nanjing, China; Changzhou High-Tech Research Institute of Nanjing University and Jiangsu Target Pharma Laboratories Inc., Changzhou, China.
| |
Collapse
|
8
|
Hameedi MA, T Prates E, Garvin MR, Mathews II, Amos BK, Demerdash O, Bechthold M, Iyer M, Rahighi S, Kneller DW, Kovalevsky A, Irle S, Vuong VQ, Mitchell JC, Labbe A, Galanie S, Wakatsuki S, Jacobson D. Structural and functional characterization of NEMO cleavage by SARS-CoV-2 3CLpro. Nat Commun 2022; 13:5285. [PMID: 36075915 PMCID: PMC9453703 DOI: 10.1038/s41467-022-32922-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 08/23/2022] [Indexed: 11/15/2022] Open
Abstract
In addition to its essential role in viral polyprotein processing, the SARS-CoV-2 3C-like protease (3CLpro) can cleave human immune signaling proteins, like NF-κB Essential Modulator (NEMO) and deregulate the host immune response. Here, in vitro assays show that SARS-CoV-2 3CLpro cleaves NEMO with fine-tuned efficiency. Analysis of the 2.50 Å resolution crystal structure of 3CLpro C145S bound to NEMO226-234 reveals subsites that tolerate a range of viral and host substrates through main chain hydrogen bonds while also enforcing specificity using side chain hydrogen bonds and hydrophobic contacts. Machine learning- and physics-based computational methods predict that variation in key binding residues of 3CLpro-NEMO helps explain the high fitness of SARS-CoV-2 in humans. We posit that cleavage of NEMO is an important piece of information to be accounted for, in the pathology of COVID-19.
Collapse
Affiliation(s)
- Mikhail A Hameedi
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Structural Molecular Biology, Menlo Park, CA, 94025, USA
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Biosciences, Menlo Park, CA, 94025, USA
- Department of Structural Biology, Stanford University, Stanford, CA, 94305, USA
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
| | - Erica T Prates
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Michael R Garvin
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Irimpan I Mathews
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Structural Molecular Biology, Menlo Park, CA, 94025, USA
| | - B Kirtley Amos
- Department of Horticulture, University of Kentucky, Lexington, KY, USA
| | - Omar Demerdash
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Mark Bechthold
- Department of Structural Biology, Stanford University, Stanford, CA, 94305, USA
| | - Mamta Iyer
- Chapman University School of Pharmacy, Irvine, CA, 92618, USA
| | - Simin Rahighi
- Chapman University School of Pharmacy, Irvine, CA, 92618, USA
| | - Daniel W Kneller
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Andrey Kovalevsky
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Stephan Irle
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Van-Quan Vuong
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee Knoxville, Knoxville, TN, USA
| | - Julie C Mitchell
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Audrey Labbe
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Stephanie Galanie
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Department of Process Research and Development, Merck & Co., Inc., Rahway, NJ, 07065, USA
| | - Soichi Wakatsuki
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Structural Molecular Biology, Menlo Park, CA, 94025, USA.
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Biosciences, Menlo Park, CA, 94025, USA.
- Department of Structural Biology, Stanford University, Stanford, CA, 94305, USA.
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA.
| | - Daniel Jacobson
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, USA.
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| |
Collapse
|
9
|
Bai ZQ, Ma X, Liu B, Huang T, Hu K. Solution structure of c-FLIP death effector domains. Biochem Biophys Res Commun 2022; 617:1-6. [PMID: 35688044 DOI: 10.1016/j.bbrc.2022.05.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 11/28/2022]
Abstract
The formation of death-inducing signaling complex (DISC) and death effector domain (DED) filament initiates extrinsic apoptosis. Recruitment and activation of procaspase-8 at the DISC are regulated by c-FLIP. The interaction between c-FLIP and procaspase-8 is mediated by their tandem DEDs (tDED). However, the structure of c-FLIPtDED and how c-FLIP interferes with procaspase-8 activation at the DISC remain elusive. Here, we solved the monomeric structure of c-FLIPtDED (F114G) at near physiological pH by solution nuclear magnetic resonance (NMR). Structural superimposition reveals c-FLIPtDED (F114G) adopts a structural topology similar to that of procaspase-8tDED. Our results provide a structural basis for understanding how c-FLIP interacts with procaspase-8 and the molecular mechanisms of c-FLIP in regulating cell death.
Collapse
Affiliation(s)
- Zhi-Qiang Bai
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Heilongtan, Kunming, 650201, Yunnan, China; Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaofang Ma
- Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Bin Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Heilongtan, Kunming, 650201, Yunnan, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tao Huang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Heilongtan, Kunming, 650201, Yunnan, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kaifeng Hu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Heilongtan, Kunming, 650201, Yunnan, China; Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| |
Collapse
|
10
|
Bagnéris C, Senthil Kumar SL, Baratchian M, Britt HM, Assafa TE, Thalassinos K, Collins MK, Barrett TE. Mechanistic insights into the activation of the IKK kinase complex by the Kaposi's Sarcoma Herpes virus oncoprotein vFLIP. J Biol Chem 2022; 298:102012. [PMID: 35525271 PMCID: PMC9163697 DOI: 10.1016/j.jbc.2022.102012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/23/2022] Open
Abstract
Constitutive activation of the canonical NF-κB signaling pathway is a major factor in Kaposi’s sarcoma-associated herpes virus pathogenesis where it is essential for the survival of primary effusion lymphoma. Central to this process is persistent upregulation of the inhibitor of κB kinase (IKK) complex by the virally encoded oncoprotein vFLIP. Although the physical interaction between vFLIP and the IKK kinase regulatory component essential for persistent activation, IKKγ, has been well characterized, it remains unclear how the kinase subunits are rendered active mechanistically. Using a combination of cell-based assays, biophysical techniques, and structural biology, we demonstrate here that vFLIP alone is sufficient to activate the IKK kinase complex. Furthermore, we identify weakly stabilized, high molecular weight vFLIP–IKKγ assemblies that are key to the activation process. Taken together, our results are the first to reveal that vFLIP-induced NF-κB activation pivots on the formation of structurally specific vFLIP–IKKγ multimers which have an important role in rendering the kinase subunits active through a process of autophosphorylation. This mechanism of NF-κB activation is in contrast to those utilized by endogenous cytokines and cellular FLIP homologues.
Collapse
Affiliation(s)
- Claire Bagnéris
- Department of Biological Sciences, Institute of Structural Molecular Biology, Birkbeck College, London, UK
| | - Swathi L Senthil Kumar
- Department of Biological Sciences, Institute of Structural Molecular Biology, Birkbeck College, London, UK
| | - Mehdi Baratchian
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Hannah M Britt
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK
| | - Tufa E Assafa
- Chemistry and Biochemistry Department, University of California Santa Cruz, Santa Cruz, California, USA
| | - Konstantinos Thalassinos
- Department of Biological Sciences, Institute of Structural Molecular Biology, Birkbeck College, London, UK; Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK
| | - Mary K Collins
- Okinawa Institute of Science and Technology, Graduate University, Onna-son, Okinawa, Japan
| | - Tracey E Barrett
- Department of Biological Sciences, Institute of Structural Molecular Biology, Birkbeck College, London, UK.
| |
Collapse
|
11
|
Hameedi MA, Prates ET, Garvin MR, Mathews I, Kirtley Amos B, Demerdash O, Bechthold M, Iyer M, Rahighi S, Kneller DW, Kovalevsky A, Irle S, Vuong V, Mitchell JC, Labbe A, Galanie S, Wakatsuki S, Jacobson D. Structural and functional characterization of NEMO cleavage by SARS-CoV-2 3CLpro.. [PMID: 34816264 PMCID: PMC8609902 DOI: 10.1101/2021.11.11.468228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In addition to its essential role in viral polyprotein processing, the SARS-CoV-2 3C-like (3CLpro) protease can cleave human immune signaling proteins, like NF-κB Essential Modulator (NEMO) and deregulate the host immune response. Here, in vitro assays show that SARS-CoV-2 3CLpro cleaves NEMO with fine-tuned efficiency. Analysis of the 2.14 Å resolution crystal structure of 3CLpro C145S bound to NEMO226–235 reveals subsites that tolerate a range of viral and host substrates through main chain hydrogen bonds while also enforcing specificity using side chain hydrogen bonds and hydrophobic contacts. Machine learning- and physics-based computational methods predict that variation in key binding residues of 3CLpro-NEMO helps explain the high fitness of SARS-CoV-2 in humans. We posit that cleavage of NEMO is an important piece of information to be accounted for in the pathology of COVID-19.
Collapse
|
12
|
Lu X, Chen Q, Liu H, Zhang X. Interplay Between Non-Canonical NF-κB Signaling and Hepatitis B Virus Infection. Front Immunol 2021; 12:730684. [PMID: 34659217 PMCID: PMC8511458 DOI: 10.3389/fimmu.2021.730684] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/13/2021] [Indexed: 12/25/2022] Open
Abstract
The non-canonical nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway is an important component of NF-κB transcription complex. Activation of this pathway mediates the development and function of host immune system involved in inflammation and viral infection. During hepatitis B virus (HBV) infection, there is a complex interaction between infected hepatocytes and the immune cells, which can hinder antiviral immune responses and is associated with pathological changes in liver tissue. Consistently, the host immune system is closely related to the severity of liver damage and the level of viral replication. Previous studies indicated that the non-canonical NF-κB signaling pathway was affected by HBV and might play an important regulatory role in the antiviral immunity. Therefore, systematically elucidating the interplay between HBV and non-canonical NF-κB signaling will contribute the discovery of more potential therapeutic targets and novel drugs to treat HBV infection.
Collapse
Affiliation(s)
- Xinyu Lu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qianhui Chen
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hongyan Liu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoyong Zhang
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| |
Collapse
|
13
|
Naimo E, Zischke J, Schulz TF. Recent Advances in Developing Treatments of Kaposi's Sarcoma Herpesvirus-Related Diseases. Viruses 2021; 13:1797. [PMID: 34578378 PMCID: PMC8473310 DOI: 10.3390/v13091797] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 12/27/2022] Open
Abstract
Kaposi-sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is the causative agent of several malignancies, including Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). Active KSHV replication has also been associated with a pathological condition called KSHV inflammatory cytokine syndrome (KICS), and KSHV may play a role in rare cases of post-transplant polyclonal lymphoproliferative disorders. Several commonly used herpesviral DNA polymerase inhibitors are active against KSHV in tissue culture. Unfortunately, they are not always efficacious against KSHV-induced diseases. To improve the outcome for the patients, new therapeutics need to be developed, including treatment strategies that target either viral proteins or cellular pathways involved in tumor growth and/or supporting the viral life cycle. In this review, we summarize the most commonly established treatments against KSHV-related diseases and review recent developments and promising new compounds that are currently under investigation or on the way to clinical use.
Collapse
Affiliation(s)
- Eleonora Naimo
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
| | - Jasmin Zischke
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
- Cluster of Excellence 2155 RESIST, Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
| |
Collapse
|
14
|
Ko MS, Biswas T, Mulero MC, Bobkov AA, Ghosh G, Huxford T. Structurally plastic NEMO and oligomerization prone IKK2 subunits define the behavior of human IKK2:NEMO complexes in solution. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140526. [PMID: 32853772 DOI: 10.1016/j.bbapap.2020.140526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 07/30/2020] [Accepted: 08/08/2020] [Indexed: 10/23/2022]
Abstract
The human IκB Kinase (IKK) is a multisubunit protein complex of two kinases and one scaffolding subunit that controls induction of transcription factor NF-κB activity. IKK behaves as an entity of aberrantly high apparent molecular weight in solution. Recent X-ray crystallographic and cryo-electron microscopy structures of individual catalytic subunits (IKK1/IKKα and IKK2/IKKβ) reveal that they are both stably folded dimeric proteins that engage in extensive homo-oligomerization through unique surfaces that are required for activation of their respective catalytic activities. The NEMO/IKKγ subunit is a predominantly coiled coil protein that is required for activation of IKK through the canonical NF-κB signaling pathway. Here we report size-exclusion chromatography, multi-angle light scattering, analytical centrifugation, and thermal denaturation analyses of full-length human recombinant NEMO as well as deletion and disease-linked variants. We observe that NEMO is predominantly a dimer in solution, although by virtue of its modular coiled coil regions NEMO exhibits complicated solution dynamics involving portions that are mutually antagonistic toward homodimerization. This behavior causes NEMO to behave as a significantly larger sized particle in solution. Analyses of NEMO in complex with IKK2 indicate that NEMO preserves this structurally dynamic character within the multisubuit complex and provides the complex-bound IKK2 further propensity toward homo-oligomerization. These observations provide critical information on the structural plasticity of NEMO subunit dimers which helps clarify its role in diseases and in IKK regulation through oligomerization-dependent phosphorylation of catalytic IKK2 subunit dimers.
Collapse
Affiliation(s)
- Myung Soo Ko
- Structural Biochemistry Laboratory, Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1030, United States; Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, United States
| | - Tapan Biswas
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, United States
| | | | - Andrey A Bobkov
- Sanford Burnham Prebys Medical Discovery Institute, United States
| | - Gourisankar Ghosh
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, United States.
| | - Tom Huxford
- Structural Biochemistry Laboratory, Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1030, United States.
| |
Collapse
|
15
|
Sadek J, Wuo MG, Rooklin D, Hauenstein A, Hong SH, Gautam A, Wu H, Zhang Y, Cesarman E, Arora PS. Modulation of virus-induced NF-κB signaling by NEMO coiled coil mimics. Nat Commun 2020; 11:1786. [PMID: 32286300 PMCID: PMC7156456 DOI: 10.1038/s41467-020-15576-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 03/12/2020] [Indexed: 01/07/2023] Open
Abstract
Protein-protein interactions featuring intricate binding epitopes remain challenging targets for synthetic inhibitors. Interactions of NEMO, a scaffolding protein central to NF-κB signaling, exemplify this challenge. Various regulators are known to interact with different coiled coil regions of NEMO, but the topological complexity of this protein has limited inhibitor design. We undertook a comprehensive effort to block the interaction between vFLIP, a Kaposi’s sarcoma herpesviral oncoprotein, and NEMO using small molecule screening and rational design. Our efforts reveal that a tertiary protein structure mimic of NEMO is necessary for potent inhibition. The rationally designed mimic engages vFLIP directly causing complex disruption, protein degradation and suppression of NF-κB signaling in primary effusion lymphoma (PEL). NEMO mimic treatment induces cell death and delays tumor growth in a PEL xenograft model. Our studies with this inhibitor reveal the critical nexus of signaling complex stability in the regulation of NF-κB by a viral oncoprotein. NF-κB signalling involves the scaffold protein NEMO, which can be bound by the oncoprotein vFLIP to promote cell survival and oncogenic transformation. Here the authors rationally engineer a tertiary protein mimic of NEMO to disrupt the vFLIP-NEMO interaction to induce cell death.
Collapse
Affiliation(s)
- Jouliana Sadek
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Michael G Wuo
- Department of Chemistry, New York University, New York, NY, 10003, USA
| | - David Rooklin
- Department of Chemistry, New York University, New York, NY, 10003, USA
| | - Arthur Hauenstein
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Seong Ho Hong
- Department of Chemistry, New York University, New York, NY, 10003, USA
| | - Archana Gautam
- Icahn School of Medicine at Mount Sinai, New York, NY, 10029-5674, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Yingkai Zhang
- Department of Chemistry, New York University, New York, NY, 10003, USA.,NYU-ECNU Center for Computational Chemistry, New York University-Shanghai, 200122, Shanghai, China
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, 10065, USA.
| | - Paramjit S Arora
- Department of Chemistry, New York University, New York, NY, 10003, USA.
| |
Collapse
|
16
|
Venkatesh J, Sekhar SC, Cheriyan VT, Muthu M, Meister P, Levi E, Dzinic S, Gauld JW, Polin LA, Rishi AK. Antagonizing binding of cell cycle and apoptosis regulatory protein 1 (CARP-1) to the NEMO/IKKγ protein enhances the anticancer effect of chemotherapy. J Biol Chem 2020; 295:3532-3552. [PMID: 32024692 DOI: 10.1074/jbc.ra119.009898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 01/03/2020] [Indexed: 12/11/2022] Open
Abstract
NF-κB is a pro-inflammatory transcription factor that critically regulates immune responses and other distinct cellular pathways. However, many NF-κB-mediated pathways for cell survival and apoptosis signaling in cancer remain to be elucidated. Cell cycle and apoptosis regulatory protein 1 (CARP-1 or CCAR1) is a perinuclear phosphoprotein that regulates signaling induced by anticancer chemotherapy and growth factors. Although previous studies have reported that CARP-1 is a part of the NF-κB proteome, regulation of NF-κB signaling by CARP-1 and the molecular mechanism(s) involved are unclear. Here, we report that CARP-1 directly binds the NF-κB-activating kinase IκB kinase subunit γ (NEMO or NF-κB essential modulator) and regulates the chemotherapy-activated canonical NF-κB pathway. Importantly, blockade of NEMO-CARP-1 binding diminished NF-κB activation, indicated by reduced phosphorylation of its subunit p65/RelA by the chemotherapeutic agent adriamycin (ADR), but not NF-κB activation induced by tumor necrosis factor α (TNFα), interleukin (IL)-1β, or epidermal growth factor. High-throughput screening of a chemical library yielded a small molecule inhibitor of NEMO-CARP-1 binding, termed selective NF-κB inhibitor 1 (SNI)-1). We noted that SNI-1 enhances chemotherapy-dependent growth inhibition of a variety of cancer cells, including human triple-negative breast cancer (TNBC) and patient-derived TNBC cells in vitro, and attenuates chemotherapy-induced secretion of the pro-inflammatory cytokines TNFα, IL-1β, and IL-8. SNI-1 also enhanced ADR or cisplatin inhibition of murine TNBC tumors in vivo and reduced systemic levels of pro-inflammatory cytokines. We conclude that inhibition of NEMO-CARP-1 binding enhances responses of cancer cells to chemotherapy.
Collapse
Affiliation(s)
- Jaganathan Venkatesh
- John D. Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, Michigan 48201; Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201; Department of Oncology, Wayne State University, Detroit, Michigan 48201
| | - Sreeja C Sekhar
- John D. Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, Michigan 48201; Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201; Department of Oncology, Wayne State University, Detroit, Michigan 48201
| | - Vino T Cheriyan
- John D. Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, Michigan 48201; Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201; Department of Oncology, Wayne State University, Detroit, Michigan 48201
| | - Magesh Muthu
- John D. Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, Michigan 48201; Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201; Department of Oncology, Wayne State University, Detroit, Michigan 48201
| | - Paul Meister
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Edi Levi
- John D. Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, Michigan 48201; Department of Pathology, Wayne State University, Detroit, Michigan 48201
| | - Sijana Dzinic
- Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201
| | - James W Gauld
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Lisa A Polin
- Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201
| | - Arun K Rishi
- John D. Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, Michigan 48201; Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201; Department of Oncology, Wayne State University, Detroit, Michigan 48201.
| |
Collapse
|
17
|
Ruder B, Günther C, Stürzl M, Neurath MF, Cesarman E, Ballon G, Becker C. Viral FLIP blocks Caspase-8 driven apoptosis in the gut in vivo. PLoS One 2020; 15:e0228441. [PMID: 31999759 PMCID: PMC6992192 DOI: 10.1371/journal.pone.0228441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/15/2020] [Indexed: 01/01/2023] Open
Abstract
A strict cell death control in the intestinal epithelium is indispensable to maintain barrier integrity and homeostasis. In order to achieve a balance between cell proliferation and cell death, a tight regulation of Caspase-8, which is a key player in controlling apoptosis, is required. Caspase-8 activity is regulated by cellular FLIP proteins. These proteins are expressed in different isoforms (cFLIPlong and cFLIPshort) which determine cell death and survival. Interestingly, several viruses encode FLIP proteins, homologous to cFLIPshort, which are described to regulate Caspase-8 and the host cell death machinery. In the current study a mouse model was generated to show the impact of viral FLIP (vFLIP) from Kaposi’s Sarcoma-associated Herpesvirus (KSHV)/ Human Herpesvirus-8 (HHV-8) on cell death regulation in the gut. Our results demonstrate that expression of vFlip in intestinal epithelial cells suppressed cFlip expression, but protected mice from lethality, tissue damage and excessive apoptotic cell death induced by genetic cFlip deletion. Finally, our model shows that vFlip expression decreases cFlip mediated Caspase-8 activation in intestinal epithelial cells. In conclusion, our data suggests that viral FLIP neutralizes and compensates for cellular FLIP, efficiently counteracting host cell death induction and facilitating further propagation in the host organism.
Collapse
Affiliation(s)
- Barbara Ruder
- Department of Medicine 1, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Claudia Günther
- Department of Medicine 1, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Stürzl
- Division of Molecular and Experimental Surgery, Department of Surgery, University of Erlangen-Nürnberg, Erlangen, Germany
| | | | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, NY, United States of America
| | - Gianna Ballon
- Department of Pathology and Laboratory Services, Cooper University Health Care, Camden, NY, United States of America
| | - Christoph Becker
- Department of Medicine 1, University of Erlangen-Nürnberg, Erlangen, Germany
- * E-mail:
| |
Collapse
|
18
|
Guven-Maiorov E, Tsai CJ, Nussinov R. Oncoviruses Can Drive Cancer by Rewiring Signaling Pathways Through Interface Mimicry. Front Oncol 2019; 9:1236. [PMID: 31803618 PMCID: PMC6872517 DOI: 10.3389/fonc.2019.01236] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/28/2019] [Indexed: 01/17/2023] Open
Abstract
Oncoviruses rewire host pathways to subvert host immunity and promote their survival and proliferation. However, exactly how is challenging to understand. Here, by employing the first and to date only interface-based host-microbe interaction (HMI) prediction method, we explore a pivotal strategy oncoviruses use to drive cancer: mimicking binding surfaces-interfaces-of human proteins. We show that oncoviruses can target key human network proteins and transform cells by acquisition of cancer hallmarks. Experimental large-scale mapping of HMIs is difficult and individual HMIs do not permit in-depth grasp of tumorigenic virulence mechanisms. Our computational approach is tractable and 3D structural HMI models can help elucidate pathogenesis mechanisms and facilitate drug design. We observe that many host proteins are unique targets for certain oncoviruses, whereas others are common to several, suggesting similar infectious strategies. A rough estimation of our false discovery rate based on the tissue expression of oncovirus-targeted human proteins is 25%.
Collapse
Affiliation(s)
- Emine Guven-Maiorov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Ruth Nussinov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
- Department of Human Genetics and Molecular Medicine, Sackler Institute of Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
19
|
Abstract
Viral infection is a major contributor to the global cancer burden. Recent advances have revealed that seven known oncogenic viruses promote tumorigenesis through shared host cell targets and pathways. A comprehensive understanding of the principles of viral oncogenesis may enable the identification of unknown infectious aetiologies of cancer and the development of therapeutic or preventive strategies for virus-associated cancers. In this Review, we discuss the molecular mechanisms of viral oncogenesis in humans. We highlight recent advances in understanding how viral manipulation of host cellular signalling, DNA damage responses, immunity and microRNA targets promotes the initiation and development of cancer.
Collapse
Affiliation(s)
- Nathan A Krump
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
20
|
Shaffer R, DeMaria AM, Kagermazova L, Liu Y, Babaei M, Caban-Penix S, Cervantes A, Jehle S, Makowski L, Gilmore TD, Whitty A, Allen KN. A Central Region of NF-κB Essential Modulator Is Required for IKKβ-Induced Conformational Change and for Signal Propagation. Biochemistry 2019; 58:2906-2920. [PMID: 31145594 DOI: 10.1021/acs.biochem.8b01316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
NF-κB essential modulator (NEMO) regulates NF-κB signaling by acting as a scaffold for the kinase IKKβ to direct its activity toward the NF-κB inhibitor, IκBα. Here, we show that a highly conserved central region of NEMO termed the intervening domain (IVD, amino acids 112-195) plays a key role in NEMO function. We determined a structural model of full-length NEMO by small-angle X-ray scattering and show that full-length, wild-type NEMO becomes more compact upon binding of a peptide comprising the NEMO binding domain of IKKβ (amino acids 701-745). Mutation of conserved IVD residues (9SG-NEMO) disrupts this conformational change in NEMO and abolishes the ability of NEMO to propagate NF-κB signaling in cells, although the affinity of 9SG-NEMO for IKKβ compared to that of the wild type is unchanged. On the basis of these results, we propose a model in which the IVD is required for a conformational change in NEMO that is necessary for its ability to direct phosphorylation of IκBα by IKKβ. Our findings suggest a molecular explanation for certain disease-associated mutations within the IVD and provide insight into the role of conformational change in signaling scaffold proteins.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Lee Makowski
- Department of Bioengineering , Northeastern University , Boston , Massachusetts 02115 , United States
| | | | | | | |
Collapse
|
21
|
Guégan JP, Ginestier C, Charafe-Jauffret E, Ducret T, Quignard JF, Vacher P, Legembre P. CD95/Fas and metastatic disease: What does not kill you makes you stronger. Semin Cancer Biol 2019; 60:121-131. [PMID: 31176682 DOI: 10.1016/j.semcancer.2019.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 12/14/2022]
Abstract
CD95 (also known as Fas) is the prototype of death receptors; however, evidence suggests that this receptor mainly implements non-apoptotic signaling pathways such as NF-κB, MAPK, and PI3K that are involved in cell migration, differentiation, survival, and cytokine secretion. At least two different forms of CD95 L exist. The multi-aggregated transmembrane ligand (m-CD95 L) is cleaved by metalloproteases to release a homotrimeric soluble ligand (s-CD95 L). Unlike m-CD95 L, the interaction between s-CD95 L and its receptor CD95 fails to trigger apoptosis, but instead promotes calcium-dependent cell migration, which contributes to the accumulation of inflammatory Th17 cells in damaged organs of lupus patients and favors cancer cell invasiveness. Novel inhibitors targeting the pro-inflammatory roles of CD95/CD95 L may provide attractive therapeutic options for patients with chronic inflammatory disorders or cancer. This review discusses the roles of the CD95/CD95 L pair in cell migration and metastasis.
Collapse
Affiliation(s)
- Jean Philippe Guégan
- CLCC Eugène Marquis, Équipe Ligue Contre Le Cancer, Rennes, France; Université Rennes, INSERM U1242, Rennes, France
| | - Christophe Ginestier
- Aix-Marseille Univ, Inserm, CNRS, Institut Paoli-Calmettes, CRCM, Epithelial Stem Cells and Cancer Lab, Marseille, France
| | - Emmanuelle Charafe-Jauffret
- Aix-Marseille Univ, Inserm, CNRS, Institut Paoli-Calmettes, CRCM, Epithelial Stem Cells and Cancer Lab, Marseille, France
| | - Thomas Ducret
- Université de Bordeaux, Bordeaux, France; Centre de Recherche Cardio Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Jean-François Quignard
- Université de Bordeaux, Bordeaux, France; Centre de Recherche Cardio Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Pierre Vacher
- Université de Bordeaux, Bordeaux, France; INSERM U1218, Bordeaux, France
| | - Patrick Legembre
- CLCC Eugène Marquis, Équipe Ligue Contre Le Cancer, Rennes, France; Université Rennes, INSERM U1242, Rennes, France.
| |
Collapse
|
22
|
Ivanisenko NV, Buchbinder JH, Espe J, Richter M, Bollmann M, Hillert LK, Ivanisenko VA, Lavrik IN. Delineating the role of c-FLIP/NEMO interaction in the CD95 network via rational design of molecular probes. BMC Genomics 2019; 20:293. [PMID: 31815628 PMCID: PMC6900753 DOI: 10.1186/s12864-019-5539-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Structural homology modeling supported by bioinformatics analysis plays a key role in uncovering new molecular interactions within gene regulatory networks. Here, we have applied this powerful approach to analyze the molecular interactions orchestrating death receptor signaling networks. In particular, we focused on the molecular mechanisms of CD95-mediated NF-κB activation and the role of c-FLIP/NEMO interaction in the induction of this pathway. RESULTS To this end, we have created the homology model of the c-FLIP/NEMO complex using the reported structure of the v-FLIP/NEMO complex, and rationally designed peptides targeting this complex. The designed peptides were based on the NEMO structure. Strikingly, the experimental in vitro validation demonstrated that the best inhibitory effects on CD95-mediated NF-κB activation are exhibited by the NEMO-derived peptides with the substitution D242Y of NEMO. Furthermore, we have assumed that the c-FLIP/NEMO complex is recruited to the DED filaments formed upon CD95 activation and validated this assumption in silico. Further insight into the function of c-FLIP/NEMO complex was provided by the analysis of evolutionary conservation of interacting regions which demonstrated that this interaction is common in distinct mammalian species. CONCLUSIONS Taken together, using a combination of bioinformatics and experimental approaches we obtained new insights into CD95-mediated NF-κB activation, providing manifold possibilities for targeting the death receptor network.
Collapse
Affiliation(s)
- Nikita V Ivanisenko
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - Jörn H Buchbinder
- Translational Inflammation research, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Johannes Espe
- Translational Inflammation research, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Max Richter
- Translational Inflammation research, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Miriam Bollmann
- Translational Inflammation research, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Laura K Hillert
- Translational Inflammation research, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Vladimir A Ivanisenko
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - Inna N Lavrik
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia. .,Translational Inflammation research, Medical Faculty, Otto von Guericke University, Magdeburg, Germany.
| |
Collapse
|
23
|
Yan L, Majerciak V, Zheng ZM, Lan K. Towards Better Understanding of KSHV Life Cycle: from Transcription and Posttranscriptional Regulations to Pathogenesis. Virol Sin 2019; 34:135-161. [PMID: 31025296 PMCID: PMC6513836 DOI: 10.1007/s12250-019-00114-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/14/2019] [Indexed: 02/08/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8 (HHV-8), is etiologically linked to the development of Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. These malignancies often occur in immunosuppressed individuals, making KSHV infection-associated diseases an increasing global health concern with persistence of the AIDS epidemic. KSHV exhibits biphasic life cycles between latent and lytic infection and extensive transcriptional and posttranscriptional regulation of gene expression. As a member of the herpesvirus family, KSHV has evolved many strategies to evade the host immune response, which help the virus establish a successful lifelong infection. In this review, we summarize the current research status on the biology of latent and lytic viral infection, the regulation of viral life cycles and the related pathogenesis.
Collapse
Affiliation(s)
- Lijun Yan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Vladimir Majerciak
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Zhi-Ming Zheng
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA.
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| |
Collapse
|
24
|
Latent infection with Kaposi's sarcoma-associated herpesvirus enhances retrotransposition of long interspersed element-1. Oncogene 2019; 38:4340-4351. [PMID: 30770900 DOI: 10.1038/s41388-019-0726-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/18/2019] [Indexed: 12/14/2022]
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV), a gamma-2 herpesvirus, is the causative agent of KS, primary effusion lymphoma (PEL), and a plasma cell variant of multicentric Castleman's disease. Although KSHV latency is detected in KS-related tumors, oncogenic pathways activated by KSHV latent infection are not fully understood. Here, we found that retrotransposition of long interspersed element-1 (L1), a retrotransposon in the human genome, was enhanced in PEL cells. Among the KSHV latent genes, viral FLICE-inhibitory protein (vFLIP) enhanced L1 retrotransposition in an NF-κB-dependent manner. Intracellular cell adhesion molecule-1 (ICAM-1), an NF-κB target, regulated the vFLIP-mediated enhancement of L1 retrotransposition. Furthermore, ICAM-1 downregulated the expression of Moloney leukemia virus 10 (MOV10), an L1 restriction factor. Knockdown of ICAM-1 or overexpression of MOV10 relieved the vFLIP-mediated enhancement of L1 retrotransposition. Collectively, during KSHV latency, vFLIP upregulates ICAM-1 in an NF-κB-dependent manner, which, in turn, downregulates MOV10 expression and thereby enhances L1 retrotransposition. Because active L1 retrotransposition can lead to genomic instability, which is commonly found in KS and PEL, activation of L1 retrotransposition during KSHV latency may accelerate oncogenic processes through enhancing genomic instability. Our results suggest that L1 retrotransposition may be a novel target for impeding tumor development in KSHV-infected patients.
Collapse
|
25
|
Mulero MC, Huxford T, Ghosh G. NF-κB, IκB, and IKK: Integral Components of Immune System Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1172:207-226. [PMID: 31628658 DOI: 10.1007/978-981-13-9367-9_10] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The NF-κB (Nuclear Factor kappa B) transcription factor plays crucial roles in the regulation of numerous biological processes including development of the immune system, inflammation, and innate and adaptive immune responses. Control over the immune cell functions of NF-κB results from signaling through one of two different routes: the canonical and noncanonical NF-κB signaling pathways. Present at the end of both pathways are the proteins NF-κB, IκB, and the IκB kinase (IKK). These proteins work together to deliver the myriad outcomes that influence context-dependent transcriptional control in immune cells. In the present chapter, we review the structural information available on NF-κB, IκB, and IKK, the critical terminal components of the NF-κB signaling, in relation to their physiological function.
Collapse
Affiliation(s)
- Maria Carmen Mulero
- Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Tom Huxford
- Structural Biochemistry Laboratory, Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182, USA
| | - Gourisankar Ghosh
- Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| |
Collapse
|
26
|
Yang Z, Honda T, Ueda K. vFLIP upregulates IKKε, leading to spindle morphology formation through RelA activation. Virology 2018; 522:106-121. [PMID: 30029010 DOI: 10.1016/j.virol.2018.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/07/2018] [Accepted: 07/07/2018] [Indexed: 12/31/2022]
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) vFLIP, a latent gene of KSHV, was first identified as a FLICE-inhibitory protein (FLIP) protecting cells from apoptosis. The vFLIP protein has been shown to activate the NF-κB signaling involved in spindle morphology formation both in HUVECs infected with KSHV and Kaposi's sarcoma (KS) itself. In this study, we independently established stably vFLIP-expressing cells and showed that they exhibited upregulated NF-κB family protein expression independent of the ability of IKKs to bind vFLIP. Further, vFLIP induced upregulation of IKKε, phosphorylation of RelA at Ser468 (p-RelA S468) and nuclear localization of Re1A concomitant with spindle morphology formation, and these effects were reversed by knockdown of IKKε and treatment with Bay-11. Overexpression of IKKε alone also showed spindle morphology formation with p-RelA S468. In conclusion, the spindle cell morphology in KS should be induced by RelA activation (p-RelA S468) by IKKε upregulation in vFLIP-expressing EA hy926 cells.
Collapse
Affiliation(s)
- Zunlin Yang
- Division of Virology, Department of Microbiology and Immunology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Tomoyuki Honda
- Division of Virology, Department of Microbiology and Immunology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Keiji Ueda
- Division of Virology, Department of Microbiology and Immunology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan.
| |
Collapse
|
27
|
Choi YB, Choi Y, Harhaj EW. Peroxisomes support human herpesvirus 8 latency by stabilizing the viral oncogenic protein vFLIP via the MAVS-TRAF complex. PLoS Pathog 2018; 14:e1007058. [PMID: 29746593 PMCID: PMC5963799 DOI: 10.1371/journal.ppat.1007058] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 05/22/2018] [Accepted: 04/25/2018] [Indexed: 12/22/2022] Open
Abstract
Human herpesvirus 8 (HHV-8) is causally related to human malignancies. HHV-8 latent viral FLICE-inhibitory protein (vFLIP) is a viral oncoprotein that is linked to pathogenesis, but how its expression is regulated is largely unknown. In an attempt to understand the role of the mitochondrial antiviral signaling (MAVS) adaptor in HHV-8 infection, we discovered that vFLIP expression was post-translationally up-regulated by the MAVS signaling complex on peroxisomes. Furthermore, we demonstrated that vFLIP could be targeted to the peroxisomes, where it was oncogenically active, in a PEX19-dependent manner. Targeted disruption of vFLIP and MAVS interaction resulted in a decrease in vFLIP expression and selectively promoted death of latently HHV-8-infected cells, providing therapeutic potential for treating HHV-8 diseases. Collectively, our experimental results suggest novel involvement of peroxisomes and MAVS in the stabilization of vFLIP and thereby in the establishment or maintenance of HHV-8 latency and associated pathogenesis.
Collapse
Affiliation(s)
- Young Bong Choi
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| | - Yeeun Choi
- Centennial High School, Ellicott City, Maryland, United States of America
| | - Edward William Harhaj
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| |
Collapse
|
28
|
Mariggiò G, Koch S, Schulz TF. Kaposi sarcoma herpesvirus pathogenesis. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0275. [PMID: 28893942 PMCID: PMC5597742 DOI: 10.1098/rstb.2016.0275] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
Kaposi sarcoma herpesvirus (KSHV), taxonomical name human gammaherpesvirus 8, is a phylogenetically old human virus that co-evolved with human populations, but is now only common (seroprevalence greater than 10%) in sub-Saharan Africa, around the Mediterranean Sea, parts of South America and in a few ethnic communities. KSHV causes three human malignancies, Kaposi sarcoma, primary effusion lymphoma, and many cases of the plasmablastic form of multicentric Castleman's disease (MCD) as well as occasional cases of plasmablastic lymphoma arising from MCD; it has also been linked to rare cases of bone marrow failure and hepatitis. As it has colonized humans physiologically for many thousand years, cofactors are needed to allow it to unfold its pathogenic potential. In most cases, these include immune defects of genetic, iatrogenic or infectious origin, and inflammation appears to play an important role in disease development. Our much improved understanding of its life cycle and its role in pathogenesis should now allow us to develop new therapeutic strategies directed against key viral proteins or intracellular pathways that are crucial for virus replication or persistence. Likewise, its limited (for a herpesvirus) distribution and transmission should offer an opportunity for the development and use of a vaccine to prevent transmission. This article is part of the themed issue ‘Human oncogenic viruses’.
Collapse
Affiliation(s)
- Giuseppe Mariggiò
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany.,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany.,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| | - Thomas F Schulz
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany .,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| |
Collapse
|
29
|
Hauenstein AV, Xu G, Kabaleeswaran V, Wu H. Evidence for M1-Linked Polyubiquitin-Mediated Conformational Change in NEMO. J Mol Biol 2017; 429:3793-3800. [PMID: 29111346 PMCID: PMC5705538 DOI: 10.1016/j.jmb.2017.10.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 11/24/2022]
Abstract
The NF-κB essential modulator (NEMO) is the scaffolding subunit of the inhibitor of κB kinase (IKK) holocomplex and is required for the activation of the catalytic IKK subunits, IKKα and IKKβ, during the canonical inflammatory response. Although structures of shorter constructs of NEMO have been solved, efforts to elucidate the full-length structure of NEMO have proved difficult due to its apparent high conformational plasticity. To better characterize the gross dimensions of full-length NEMO, we employed in-line size exclusion chromatography-small-angle X-ray scattering. We show that NEMO adopts a more compact conformation (Dmax=320Å) than predicted for a fully extended coiled-coil structure (>500Å). In addition, we map a region of NEMO (residues 112-150) in its coiled-coil 1 domain that impedes the binding of linear (M1-linked) di-ubiquitin to its coiled-coil 2-leucine zipper ubiquitin binding domain. This ubiquitin binding inhibition can be overcome by a longer chain of linear, but not K63-linked polyubiquitin. Collectively, these observations suggest that NEMO may be auto-inhibited in the resting state by intramolecular interactions and that during signaling, NEMO may be allosterically activated by binding to long M1-linked polyubiquitin chains.
Collapse
Affiliation(s)
- Arthur V Hauenstein
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, United States
| | - Guozhou Xu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, United States
| | - Venkataraman Kabaleeswaran
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, United States
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, United States.
| |
Collapse
|
30
|
IKKγ-Mimetic Peptides Block the Resistance to Apoptosis Associated with Kaposi's Sarcoma-Associated Herpesvirus Infection. J Virol 2017; 91:JVI.01170-17. [PMID: 28931678 PMCID: PMC5686756 DOI: 10.1128/jvi.01170-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 08/31/2017] [Indexed: 11/20/2022] Open
Abstract
Primary effusion lymphoma (PEL) is a lymphogenic disorder associated with Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Key to the survival and proliferation of PEL is the canonical NF-κB pathway, which becomes constitutively activated following overexpression of the viral oncoprotein KSHV vFLIP (ks-vFLIP). This arises from its capacity to form a complex with the modulatory subunit of the IκB kinase (IKK) kinase, IKKγ (or NEMO), resulting in the overproduction of proteins that promote cellular survival and prevent apoptosis, both of which are important drivers of tumorigenesis. Using a combination of cell-based and biophysical assays together with structural techniques, we showed that the observed resistance to cell death is largely independent of autophagy or major death receptor signaling pathways and demonstrated that direct targeting of the ks-vFLIP–IKKγ interaction both in cells and in vitro can be achieved using IKKγ-mimetic peptides. Our results further reveal that these peptides not only induce cell killing but also potently sensitize PEL to the proapoptotic agents tumor necrosis factor alpha and etoposide and are the first to confirm ks-vFLIP as a tractable target for the treatment of PEL and related disorders. IMPORTANCE KSHV vFLIP (ks-vFLIP) has been shown to have a crucial role in cellular transformation, in which it is vital for the survival and proliferation of primary effusion lymphoma (PEL), an aggressive malignancy associated with infection that is resistant to the majority of chemotherapeutic drugs. It operates via subversion of the canonical NF-κB pathway, which requires a physical interaction between ks-vFLIP and the IKK kinase modulatory subunit IKKγ. While this interaction has been directly linked to protection against apoptosis, it is unclear whether the suppression of other cell death pathways implicated in ks-vFLIP pathogenesis is an additional contributor. We demonstrate that the interaction between ks-vFLIP and IKKγ is pivotal in conferring resistance to apoptosis. Additionally, we show that the ks-vFLIP–IKKγ complex can be disrupted using peptides leading to direct killing and the sensitization of PEL cells to proapoptotic agents. Our studies thus provide a framework for future therapeutic interventions.
Collapse
|
31
|
Abere B, Mamo TM, Hartmann S, Samarina N, Hage E, Rückert J, Hotop SK, Büsche G, Schulz TF. The Kaposi's sarcoma-associated herpesvirus (KSHV) non-structural membrane protein K15 is required for viral lytic replication and may represent a therapeutic target. PLoS Pathog 2017; 13:e1006639. [PMID: 28938025 PMCID: PMC5627962 DOI: 10.1371/journal.ppat.1006639] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/04/2017] [Accepted: 09/09/2017] [Indexed: 12/18/2022] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is the infectious cause of the highly vascularized tumor Kaposi’s sarcoma (KS), which is characterized by proliferating spindle cells of endothelial origin, extensive neo-angiogenesis and inflammatory infiltrates. The KSHV K15 protein contributes to the angiogenic and invasive properties of KSHV-infected endothelial cells. Here, we asked whether K15 could also play a role in KSHV lytic replication. Deletion of the K15 gene from the viral genome or its depletion by siRNA lead to reduced virus reactivation, as evidenced by the decreased expression levels of KSHV lytic proteins RTA, K-bZIP, ORF 45 and K8.1 as well as reduced release of infectious virus. Similar results were found for a K1 deletion virus. Deleting either K15 or K1 from the viral genome also compromised the ability of KSHV to activate PLCγ1, Erk1/2 and Akt1. In infected primary lymphatic endothelial (LEC-rKSHV) cells, which have previously been shown to spontaneously display a viral lytic transcription pattern, transfection of siRNA against K15, but not K1, abolished viral lytic replication as well as KSHV-induced spindle cell formation. Using a newly generated monoclonal antibody to K15, we found an abundant K15 protein expression in KS tumor biopsies obtained from HIV positive patients, emphasizing the physiological relevance of our findings. Finally, we used a dominant negative inhibitor of the K15-PLCγ1 interaction to establish proof of principle that pharmacological intervention with K15-dependent pathways may represent a novel approach to block KSHV reactivation and thereby its pathogenesis. Both the latent and lytic replication phases of the KSHV life cycle are thought to contribute to its persistence and pathogenesis. The non-structural signaling membrane protein K15 is involved in the angiogenic and invasive properties of KSHV-infected endothelial cells. Here we show that the K15 protein is required for virus replication, early viral gene expression and virus production through its activation of the cellular signaling pathways PLCγ1 and Erk 1/2. K15 is abundantly expressed in KSHV-infected lymphatic endothelial cells (LECs) and contributes to KSHV-induced endothelial spindle cell formation. The abundant K15 protein expression observed in LECs is also observed in KS tumors. We also show that it may be possible to target K15 in order to intervene therapeutically with KSHV lytic replication and pathogenesis.
Collapse
Affiliation(s)
- Bizunesh Abere
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Tamrat M. Mamo
- Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Silke Hartmann
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Naira Samarina
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Elias Hage
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Jessica Rückert
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Sven-Kevin Hotop
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
- Department of Chemical Biology, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Guntram Büsche
- Institute of Pathology, Hannover Medical School, Hannover, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
- * E-mail:
| |
Collapse
|
32
|
Molluscum Contagiosum Virus MC159 Abrogates cIAP1-NEMO Interactions and Inhibits NEMO Polyubiquitination. J Virol 2017; 91:JVI.00276-17. [PMID: 28515292 DOI: 10.1128/jvi.00276-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/05/2017] [Indexed: 12/20/2022] Open
Abstract
Molluscum contagiosum virus (MCV) is a dermatotropic poxvirus that causes benign skin lesions. MCV lesions persist because of virally encoded immune evasion molecules that inhibit antiviral responses. The MCV MC159 protein suppresses NF-κB activation, a powerful antiviral response, via interactions with the NF-κB essential modulator (NEMO) subunit of the IκB kinase (IKK) complex. Binding of MC159 to NEMO does not disrupt the IKK complex, implying that MC159 prevents IKK activation via an as-yet-unidentified strategy. Here, we demonstrated that MC159 inhibited NEMO polyubiquitination, a posttranslational modification required for IKK and downstream NF-κB activation. Because MCV cannot be propagated in cell culture, MC159 was expressed independent of infection or during a surrogate vaccinia virus infection to identify how MC159 prevented polyubiquitination. Cellular inhibitor of apoptosis protein 1 (cIAP1) is a cellular E3 ligase that ubiquitinates NEMO. Mutational analyses revealed that MC159 and cIAP1 each bind to the same NEMO region, suggesting that MC159 may competitively inhibit cIAP1-NEMO interactions. Indeed, MC159 prevented cIAP1-NEMO interactions. MC159 also diminished cIAP1-mediated NEMO polyubiquitination and cIAP1-induced NF-κB activation. These data suggest that MC159 competitively binds to NEMO to prevent cIAP1-induced NEMO polyubiquitination. To our knowledge, this is the first report of a viral protein disrupting NEMO-cIAP1 interactions to strategically suppress IKK activation. All viruses must antagonize antiviral signaling events for survival. We hypothesize that MC159 inhibits NEMO polyubiquitination as a clever strategy to manipulate the host cell environment to the benefit of the virus.IMPORTANCE Molluscum contagiosum virus (MCV) is a human-specific poxvirus that causes persistent skin neoplasms. The persistence of MCV has been attributed to viral downregulation of host cell immune responses such as NF-κB activation. We show here that the MCV MC159 protein interacts with the NEMO subunit of the IKK complex to prevent NEMO interactions with the cIAP1 E3 ubiquitin ligase. This interaction correlates with a dampening of cIAP1 to polyubiquitinate NEMO and to activate NF-κB. This inhibition of cIAP1-NEMO interactions is a new viral strategy to minimize IKK activation and to control NEMO polyubiquitination. This research provides new insights into mechanisms that persistent viruses may use to cause long-term infection of host cells.
Collapse
|
33
|
Mariggiò G, Koch S, Zhang G, Weidner-Glunde M, Rückert J, Kati S, Santag S, Schulz TF. Kaposi Sarcoma Herpesvirus (KSHV) Latency-Associated Nuclear Antigen (LANA) recruits components of the MRN (Mre11-Rad50-NBS1) repair complex to modulate an innate immune signaling pathway and viral latency. PLoS Pathog 2017; 13:e1006335. [PMID: 28430817 PMCID: PMC5415203 DOI: 10.1371/journal.ppat.1006335] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 05/03/2017] [Accepted: 04/05/2017] [Indexed: 12/31/2022] Open
Abstract
Kaposi Sarcoma Herpesvirus (KSHV), a γ2-herpesvirus and class 1 carcinogen, is responsible for at least three human malignancies: Kaposi Sarcoma (KS), Primary Effusion Lymphoma (PEL) and Multicentric Castleman's Disease (MCD). Its major nuclear latency protein, LANA, is indispensable for the maintenance and replication of latent viral DNA in infected cells. Although LANA is mainly a nuclear protein, cytoplasmic isoforms of LANA exist and can act as antagonists of the cytoplasmic DNA sensor, cGAS. Here, we show that cytosolic LANA also recruits members of the MRN (Mre11-Rad50-NBS1) repair complex in the cytosol and thereby inhibits their recently reported role in the sensing of cytoplasmic DNA and activation of the NF-κB pathway. Inhibition of NF-κB activation by cytoplasmic LANA is accompanied by increased lytic replication in KSHV-infected cells, suggesting that MRN-dependent NF-κB activation contributes to KSHV latency. Cytoplasmic LANA may therefore support the activation of KSHV lytic replication in part by counteracting the activation of NF-κB in response to cytoplasmic DNA. This would complement the recently described role of cytoplasmic LANA in blocking an interferon response triggered by cGAS and thereby promoting lytic reactivation. Our findings highlight a second point at which cytoplasmic LANA interferes with the innate immune response, as well as the importance of the recently discovered role of cytoplasmic MRN complex members as innate sensors of cytoplasmic DNA for the control of KSHV replication.
Collapse
MESH Headings
- Acid Anhydride Hydrolases
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cytoplasm/metabolism
- DNA Repair Enzymes/genetics
- DNA Repair Enzymes/metabolism
- DNA Replication
- DNA, Viral/genetics
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- HEK293 Cells
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/immunology
- Herpesvirus 8, Human/physiology
- Humans
- Immunity, Innate
- MRE11 Homologue Protein
- Models, Biological
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Nuclear Proteins/genetics
- Nuclear Proteins/immunology
- Nuclear Proteins/metabolism
- Protein Isoforms
- Sarcoma, Kaposi/immunology
- Sarcoma, Kaposi/virology
- Signal Transduction
- Virus Latency
- Virus Replication
Collapse
Affiliation(s)
- Giuseppe Mariggiò
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Guigen Zhang
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Magdalena Weidner-Glunde
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Jessica Rückert
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Semra Kati
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Susann Santag
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover-Braunschweig Site, Germany
| |
Collapse
|
34
|
Fu TM, Li Y, Lu A, Li Z, Vajjhala PR, Cruz AC, Srivastava DB, DiMaio F, Penczek PA, Siegel RM, Stacey KJ, Egelman EH, Wu H. Cryo-EM Structure of Caspase-8 Tandem DED Filament Reveals Assembly and Regulation Mechanisms of the Death-Inducing Signaling Complex. Mol Cell 2016; 64:236-250. [PMID: 27746017 PMCID: PMC5089849 DOI: 10.1016/j.molcel.2016.09.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/10/2016] [Accepted: 09/07/2016] [Indexed: 12/20/2022]
Abstract
Caspase-8 activation can be triggered by death receptor-mediated formation of the death-inducing signaling complex (DISC) and by the inflammasome adaptor ASC. Caspase-8 assembles with FADD at the DISC and with ASC at the inflammasome through its tandem death effector domain (tDED), which is regulated by the tDED-containing cellular inhibitor cFLIP and the viral inhibitor MC159. Here we present the caspase-8 tDED filament structure determined by cryoelectron microscopy. Extensive assembly interfaces not predicted by the previously proposed linear DED chain model were uncovered, and were further confirmed by structure-based mutagenesis in filament formation in vitro and Fas-induced apoptosis and ASC-mediated caspase-8 recruitment in cells. Structurally, the two DEDs in caspase-8 use quasi-equivalent contacts to enable assembly. Using the tDED filament structure as a template, structural analyses reveal the interaction surfaces between FADD and caspase-8 and the distinct mechanisms of regulation by cFLIP and MC159 through comingling and capping, respectively.
Collapse
Affiliation(s)
- Tian-Min Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Yang Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Alvin Lu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Zongli Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Parimala R Vajjhala
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Anthony C Cruz
- Autoimmunity Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Devendra B Srivastava
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Pawel A Penczek
- Department of Biochemistry and Molecular Biology, University of Texas-Houston Medical School, Houston, TX 77030, USA
| | - Richard M Siegel
- Autoimmunity Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Katryn J Stacey
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
| |
Collapse
|
35
|
Baratchian M, Davis CA, Shimizu A, Escors D, Bagnéris C, Barrett T, Collins MK. Distinct Activation Mechanisms of NF-κB Regulator Inhibitor of NF-κB Kinase (IKK) by Isoforms of the Cell Death Regulator Cellular FLICE-like Inhibitory Protein (cFLIP). J Biol Chem 2016; 291:7608-20. [PMID: 26865630 PMCID: PMC4817188 DOI: 10.1074/jbc.m116.718122] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Indexed: 11/06/2022] Open
Abstract
The viral FLICE-like inhibitory protein (FLIP) protein from Kaposi sarcoma-associated herpesvirus activates the NF-κB pathway by forming a stable complex with a central region (amino acids 150-272) of the inhibitor of NF-κB kinase (IKK) γ subunits, thereby activating IKK. Cellular FLIP (cFLIP) forms are also known to activate the NF-κB pathway via IKK activation. Here we demonstrate that cFLIPL, cFLIPS, and their proteolytic product p22-FLIP all require the C-terminal region of NEMO/IKKγ (amino acids 272-419) and its ubiquitin binding function for activation of the IKK kinase (or kinase complex), but none form a stable complex with IKKγ. Our results further reveal that cFLIPLrequires the linear ubiquitin chain assembly complex and the kinase TAK1 for activation of the IKK kinase. Similarly, cFLIPSand p22-FLIP also require TAK1 but do not require LUBAC. In contrast, these isoforms are both components of complexes that incorporate Fas-associated death domain and RIP1, which appear essential for kinase activation. This conservation of IKK activation among the cFLIP family using different mechanisms suggests that the mechanism plays a critical role in their function.
Collapse
Affiliation(s)
- Mehdi Baratchian
- From the Medical Research Council Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London WC1E 6BT, United Kingdom, Division of Advanced Therapies, National Institute of Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts EN6 3QG, United Kingdom, and
| | - Christopher A Davis
- From the Medical Research Council Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London WC1E 6BT, United Kingdom
| | - Akira Shimizu
- From the Medical Research Council Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London WC1E 6BT, United Kingdom
| | - David Escors
- From the Medical Research Council Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London WC1E 6BT, United Kingdom
| | - Claire Bagnéris
- Institute of Structural and Molecular Biology, School of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Tracey Barrett
- Institute of Structural and Molecular Biology, School of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Mary K Collins
- From the Medical Research Council Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London WC1E 6BT, United Kingdom, Division of Advanced Therapies, National Institute of Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts EN6 3QG, United Kingdom, and
| |
Collapse
|
36
|
Schulz TF, Cesarman E. Kaposi Sarcoma-associated Herpesvirus: mechanisms of oncogenesis. Curr Opin Virol 2015; 14:116-28. [PMID: 26431609 DOI: 10.1016/j.coviro.2015.08.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 08/30/2015] [Indexed: 10/23/2022]
Abstract
Kaposi Sarcoma-associated Herpesvirus (KSHV, HHV8) causes three human malignancies, Kaposi Sarcoma (KS), an endothelial tumor, as well as Primary Effusion Lymphoma (PEL) and the plasma cell variant of Multicentric Castleman's Disease (MCD), two B-cell lymphoproliferative diseases. All three cancers occur primarily in the context of immune deficiency and/or HIV infection, but their pathogenesis differs. KS most likely results from the combined effects of an endotheliotropic virus with angiogenic properties and inflammatory stimuli and thus represents an interesting example of a cancer that arises in an inflammatory context. Viral and cellular angiogenic and inflammatory factors also play an important role in the pathogenesis of MCD. In contrast, PEL represents an autonomously growing malignancy that is, however, still dependent on the continuous presence of KSHV and the action of several KSHV proteins.
Collapse
Affiliation(s)
- Thomas F Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany; German Centre of Infection Research, Hannover-Braunschweig Site, Hannover, Germany.
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, USA.
| |
Collapse
|
37
|
Singh N, Hassan A, Bose K. Molecular basis of death effector domain chain assembly and its role in caspase-8 activation. FASEB J 2015; 30:186-200. [PMID: 26370846 DOI: 10.1096/fj.15-272997] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/31/2015] [Indexed: 12/20/2022]
Abstract
Assembly of a death-inducing signaling complex is a key event in the extrinsic apoptotic pathway, enabling activation of the caspase cascade and subsequent cell death. However, the molecular events governing DISC assembly have remained largely elusive because of the lack of information on mechanism and specificity regulating the death effector domain (DED)-DED interaction network. Using molecular modeling, mutagenesis, and biochemical and ex vivo experiments, we identified the precise binding interface and hot spots crucial for intermolecular DED chain assembly. Mutation of key interface residues (Leu42/Phe45) in procaspase-8 DED-A completely abrogated DED chain formation in HEK293 cells and prevented its association with FADD. A significant 2.6-3.6-fold reduction in procaspase-8 activation was observed in functional cell-death assays after substitution of the interfacial residues. Based on our results we propose a new model for DISC formation that refines the current understanding of the activation mechanism. Upon stimulation, FADD self-associates weakly via reciprocal interaction between helices α1/α4 and α2/α3 of the DED to form an oligomeric signaling platform that provides a stage for the initial recruitment of procaspase-8 through direct interaction with α1/α4 of DED-A, followed by sequential interaction mediated by helices α2/α5 of DED-B, to form the procaspase-8 DED chain that is crucial for its activation and subsequent cell death.
Collapse
Affiliation(s)
- Nitu Singh
- Integrated Biophysics and Structural Biology Laboratory, Advanced Centre for Treatment, Research, and Education in Cancer, Navi Mumbai, India
| | - Ali Hassan
- Integrated Biophysics and Structural Biology Laboratory, Advanced Centre for Treatment, Research, and Education in Cancer, Navi Mumbai, India
| | - Kakoli Bose
- Integrated Biophysics and Structural Biology Laboratory, Advanced Centre for Treatment, Research, and Education in Cancer, Navi Mumbai, India
| |
Collapse
|
38
|
Abstract
Death-inducing signaling complex (DISC) is a platform for the activation of initiator caspase in extrinsic apoptosis. Assembly of DISC is accomplished by two different types of homotypic interaction: one is between death domains (DDs) of a death receptor and FADD, and the other is between death effecter domains (DEDs) of FADD, procaspase-8/-10 and cFLIP. Recent biochemical investigations on the stoichiometry of DISC have revealed that single-DED-containing FADD exists in DISC in a substantially lower abundance than the sum of tandem-DEDs-containing components that are procaspase-8 and cFLIP. In addition, the homology models of the tandem DEDs in procaspase-8 and cFLIP show that two different interaction faces, H1-H4 face and H2-H5 face, are exposed for possible inter-molecular DED-DED interactions. These recent findings led to a proposal of the DED chain model for the interactions between FADD, procaspase-8 and cFLIP in DISC. This emerging view provides new insights on the topology of DED-DED network in DISC and furthermore on how procaspase-8 and cFLIP cluster for dimerization and proteolytic activation.
Collapse
Affiliation(s)
- Jin Kuk Yang
- Department of Chemistry, School of Natural Sciences, Soongsil University, Seoul, 156-743, Korea,
| |
Collapse
|
39
|
Bagnéris C, Rogala KB, Baratchian M, Zamfir V, Kunze MBA, Dagless S, Pirker KF, Collins MK, Hall BA, Barrett TE, Kay CWM. Probing the Solution Structure of IκB Kinase (IKK) Subunit γ and Its Interaction with Kaposi Sarcoma-associated Herpes Virus Flice-interacting Protein and IKK Subunit β by EPR Spectroscopy. J Biol Chem 2015; 290:16539-49. [PMID: 25979343 PMCID: PMC4505408 DOI: 10.1074/jbc.m114.622928] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 05/13/2015] [Indexed: 01/04/2023] Open
Abstract
Viral flice-interacting protein (vFLIP), encoded by the oncogenic Kaposi sarcoma-associated herpes virus (KSHV), constitutively activates the canonical nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) pathway. This is achieved through subversion of the IκB kinase (IKK) complex (or signalosome), which involves a physical interaction between vFLIP and the modulatory subunit IKKγ. Although this interaction has been examined both in vivo and in vitro, the mechanism by which vFLIP activates the kinase remains to be determined. Because IKKγ functions as a scaffold, recruiting both vFLIP and the IKKα/β subunits, it has been proposed that binding of vFLIP could trigger a structural rearrangement in IKKγ conducive to activation. To investigate this hypothesis we engineered a series of mutants along the length of the IKKγ molecule that could be individually modified with nitroxide spin labels. Subsequent distance measurements using electron paramagnetic resonance spectroscopy combined with molecular modeling and molecular dynamics simulations revealed that IKKγ is a parallel coiled-coil whose response to binding of vFLIP or IKKβ is localized twisting/stiffening and not large-scale rearrangements. The coiled-coil comprises N- and C-terminal regions with distinct registers accommodated by a twist: this structural motif is exploited by vFLIP, allowing it to bind and subsequently activate the NF-κB pathway. In vivo assays confirm that NF-κB activation by vFLIP only requires the N-terminal region up to the transition between the registers, which is located directly C-terminal of the vFLIP binding site.
Collapse
Affiliation(s)
- Claire Bagnéris
- From the Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
| | - Kacper B Rogala
- From the Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom, Institute of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Mehdi Baratchian
- MRC Centre for Medical Molecular Virology, UCL Cancer Institute and National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts EN6 3QG, United Kingdom
| | - Vlad Zamfir
- From the Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom, Institute of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Micha B A Kunze
- Institute of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Selina Dagless
- Institute of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Katharina F Pirker
- Institute of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Mary K Collins
- MRC Centre for Medical Molecular Virology, UCL Cancer Institute and National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts EN6 3QG, United Kingdom
| | - Benjamin A Hall
- MRC Cancer Unit, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0XZ, United Kingdom, and
| | - Tracey E Barrett
- From the Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom,
| | - Christopher W M Kay
- Institute of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom, London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| |
Collapse
|
40
|
Hwang EY, Jeong MS, Park SY, Jang SB. Evidence of complex formation between FADD and c-FLIP death effector domains for the death inducing signaling complex. BMB Rep 2015; 47:488-93. [PMID: 24355299 PMCID: PMC4206723 DOI: 10.5483/bmbrep.2014.47.9.239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Indexed: 01/18/2023] Open
Abstract
Adaptor protein FADD forms the death inducing signaling complex (DISC) by recruiting the initiating caspases-8 and -10 through homotypic death effector domain (DED) interactions. Cellular FLICE-inhibitory protein (c-FLIP) is an inhibitor of death ligand-induced apoptosis downstream of death receptors, and FADD competes with procaspase-8/10 for recruitment for DISC. However, the mechanism of action of FADD and c-FLIP proteins remain poorly understood at the molecular level. In this study, we provide evidence indicating that the death effector domain (DED) of FADD interacts directly with the death effector domain of human c-FLIP. In addition, we use homology modeling to develop a molecular docking model of FADD and c-FLIP proteins. We also find that four structure-based mutants (E80A, L84A, K169A and Y171A) of c-FLIP DEDs disturb the interaction with FADD DED, and that these mutations lower the stability of the c-FLIP DED. [BMB Reports 2014; 47(9): 488-493]
Collapse
Affiliation(s)
- Eun Young Hwang
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busan 609-735, Korea
| | - Mi Suk Jeong
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busan 609-735, Korea
| | - So Young Park
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busan 609-735, Korea
| | - Se Bok Jang
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busan 609-735, Korea
| |
Collapse
|
41
|
Abstract
Molluscum contagiosum virus (MCV) is the causative agent of molluscum contagiosum (MC), the third most common viral skin infection in children, and one of the five most prevalent skin diseases worldwide. No FDA-approved treatments, vaccines, or commercially available rapid diagnostics for MCV are available. This review discusses several aspects of this medically important virus including: physical properties of MCV, MCV pathogenesis, MCV replication, and immune responses to MCV infection. Sequencing of the MCV genome revealed novel immune evasion molecules which are highlighted here. Special attention is given to the MCV MC159 and MC160 proteins. These proteins are FLIPs with homologs in gamma herpesviruses and in the cell. They are of great interest because each protein regulates apoptosis, NF-κB, and IRF3. However, the mechanism that each protein uses to impart its effects is different. It is important to elucidate how MCV inhibits immune responses; this knowledge contributes to our understanding of viral pathogenesis and also provides new insights into how the immune system neutralizes virus infections.
Collapse
|
42
|
Abstract
Cellular apoptosis is of major importance in the struggle between virus and host. Although many viruses use various strategies to control the cell death machinery by encoding anti-apoptotic virulence factors, it is now becoming clear that, in addition to their role in inhibiting apoptosis, these factors function in multiple immune and metabolic pathways to promote fitness and pathogenesis. In this Progress article, we discuss novel functions of viral anti-apoptotic factors in the regulation of autophagy, in the nuclear factor-κB (NF-κB) pathway and in interferon signalling, with a focus on persistent and oncogenic gammaherpesviruses. If viral anti-apoptotic proteins are to be properly exploited as targets for antiviral drugs, their diverse and complex roles should be considered.
Collapse
Affiliation(s)
- Chengyu Liang
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California 90033, USA
| | - Byung-Ha Oh
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California 90033, USA
| |
Collapse
|
43
|
Zhou L, Yeo AT, Ballarano C, Weber U, Allen KN, Gilmore TD, Whitty A. Disulfide-mediated stabilization of the IκB kinase binding domain of NF-κB essential modulator (NEMO). Biochemistry 2014; 53:7929-44. [PMID: 25400026 PMCID: PMC4278678 DOI: 10.1021/bi500920n] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Human NEMO (NF-κB
essential modulator) is a 419 residue scaffolding
protein that, together with catalytic subunits IKKα and IKKβ,
forms the IκB kinase (IKK) complex, a key regulator of NF-κB
pathway signaling. NEMO is an elongated homodimer comprising mostly
α-helix. It has been shown that a NEMO fragment spanning residues
44–111, which contains the IKKα/β binding site,
is structurally disordered in the absence of bound IKKβ. Herein
we show that enforcing dimerization of NEMO1–120 or NEMO44–111 constructs through introduction
of one or two interchain disulfide bonds, through oxidation of the
native Cys54 residue and/or at position 107 through a Leu107Cys mutation,
induces a stable α-helical coiled-coil structure that is preorganized
to bind IKKβ with high affinity. Chemical and thermal denaturation
studies showed that, in the context of a covalent dimer, the ordered
structure was stabilized relative to the denatured state by up to
3 kcal/mol. A full-length NEMO-L107C protein formed covalent dimers
upon treatment of mammalian cells with H2O2.
Furthermore, NEMO-L107C bound endogenous IKKβ in A293T cells,
reconstituted TNF-induced NF-κB signaling in NEMO-deficient
cells, and interacted with TRAF6. Our results indicate that the IKKβ
binding domain of NEMO possesses an ordered structure in the unbound
state, provided that it is constrained within a dimer as is the case
in the constitutively dimeric full-length NEMO protein. The stability
of the NEMO coiled coil is maintained by strong interhelix interactions
in the region centered on residue 54. The disulfide-linked constructs
we describe herein may be useful for crystallization of NEMO’s
IKKβ binding domain in the absence of bound IKKβ, thereby
facilitating the structural characterization of small-molecule inhibitors.
Collapse
Affiliation(s)
- Li Zhou
- Department of Chemistry and ‡Department of Biology, Boston University , Boston, Massachusetts 02215, United States
| | | | | | | | | | | | | |
Collapse
|
44
|
Lo YC, Lin SC, Yang CY, Tung JY. Tandem DEDs and CARDs suggest novel mechanisms of signaling complex assembly. Apoptosis 2014; 20:124-35. [DOI: 10.1007/s10495-014-1054-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
45
|
Othman Z, Sulaiman MK, Willcocks MM, Ulryck N, Blackbourn DJ, Sargueil B, Roberts LO, Locker N. Functional analysis of Kaposi's sarcoma-associated herpesvirus vFLIP expression reveals a new mode of IRES-mediated translation. RNA (NEW YORK, N.Y.) 2014; 20:1803-1814. [PMID: 25246653 PMCID: PMC4201831 DOI: 10.1261/rna.045328.114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 08/26/2014] [Indexed: 06/03/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus, the etiological agent of Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). One of the key viral proteins that contributes to tumorigenesis is vFLIP, a viral homolog of the FLICE inhibitory protein. This KSHV protein interacts with the NFκB pathway to trigger the expression of antiapoptotic and proinflammatory genes and ultimately leads to tumor formation. The expression of vFLIP is regulated at the translational level by an internal ribosomal entry site (IRES) element. However, the precise mechanism by which ribosomes are recruited internally and the exact location of the IRES has remained elusive. Here we show that a 252-nt fragment directly upstream of vFLIP, within a coding region, directs translation. We have established its RNA structure and demonstrate that IRES activity requires the presence of eIF4A and an intact eIF4G. Furthermore, and unusually for an IRES, eIF4E is part of the complex assembled onto the vFLIP IRES to direct translation. These molecular interactions define a new paradigm for IRES-mediated translation.
Collapse
Affiliation(s)
- Zulkefley Othman
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Mariam K Sulaiman
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Margaret M Willcocks
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Nathalie Ulryck
- Faculté des Sciences Pharmaceutiques et Biologiques, UMR8015, Université Paris Descartes, 75270 Paris, France
| | - David J Blackbourn
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Bruno Sargueil
- Faculté des Sciences Pharmaceutiques et Biologiques, UMR8015, Université Paris Descartes, 75270 Paris, France
| | - Lisa O Roberts
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| |
Collapse
|
46
|
Hauenstein AV, Rogers WE, Shaul JD, Huang DB, Ghosh G, Huxford T. Probing kinase activation and substrate specificity with an engineered monomeric IKK2. Biochemistry 2014; 53:2064-73. [PMID: 24611898 PMCID: PMC3977576 DOI: 10.1021/bi401551r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Catalytic
subunits of the IκB kinase (IKK), IKK1/IKKα,
and IKK2/IKKβ function in vivo as dimers in
association with the necessary scaffolding subunit NEMO/IKKγ.
Recent X-ray crystal structures of IKK2 suggested that dimerization
might be mediated by a smaller protein–protein interaction
than previously thought. Here, we report that removal of a portion
of the scaffold dimerization domain (SDD) of human IKK2 yields a kinase
subunit that remains monomeric in solution. Expression in baculovirus-infected
Sf9 insect cells and purification of this engineered monomeric human
IKK2 enzyme allows for in vitro analysis of its substrate
specificity and mechanism of activation. We find that the monomeric
enzyme, which contains all of the amino-terminal kinase and ubiquitin-like
domains as well as the more proximal portions of the SDD, functions in vitro to direct phosphorylation exclusively to residues
S32 and S36 of its IκBα substrate. Thus, the NF-κB-inducing
potential of IKK2 is preserved in the engineered monomer. Furthermore,
we observe that our engineered IKK2 monomer readily autophosphorylates
activation loop serines 177 and 181 in trans. However, when residues
that were previously observed to interfere with IKK2 trans autophosphorylation
in transfected cells are mutated within the context of the monomer,
the resulting Sf9 cell expressed and purified proteins were significantly
impaired in their trans autophosphorylation activity in vitro. This study further defines the determinants of substrate specificity
and provides additional evidence in support of a model in which activation
via trans autophosphorylation of activation loop serines in IKK2 requires
transient assembly of higher-order oligomers.
Collapse
Affiliation(s)
- Arthur V Hauenstein
- Structural Biochemistry Laboratory, Department of Chemistry & Biochemistry, San Diego State University , 5500 Campanile Drive, San Diego, California 92182-1030, United States
| | | | | | | | | | | |
Collapse
|
47
|
NEMO is essential for Kaposi's sarcoma-associated herpesvirus-encoded vFLIP K13-induced gene expression and protection against death receptor-induced cell death, and its N-terminal 251 residues are sufficient for this process. J Virol 2014; 88:6345-54. [PMID: 24672029 DOI: 10.1128/jvi.00028-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 was originally believed to protect virally infected cells against death receptor-induced apoptosis by interfering with caspase 8/FLICE activation. Subsequent studies revealed that K13 also activates the NF-κB pathway by binding to the NEMO/inhibitor of NF-κB (IκB) kinase gamma (IKKγ) subunit of an IKK complex and uses this pathway to modulate the expression of genes involved in cellular survival, proliferation, and the inflammatory response. However, it is not clear if K13 can also induce gene expression independently of NEMO/IKKγ. The minimum region of NEMO that is sufficient for supporting K13-induced NF-κB has not been delineated. Furthermore, the contribution of NEMO and NF-κB to the protective effect of K13 against death receptor-induced apoptosis remains to be determined. In this study, we used microarray analysis on K13-expressing wild-type and NEMO-deficient cells to demonstrate that NEMO is required for modulation of K13-induced genes. Reconstitution of NEMO-null cells revealed that the N-terminal 251 amino acid residues of NEMO are sufficient for supporting K13-induced NF-κB but fail to support tumor necrosis factor alpha (TNF-α)-induced NF-κB. K13 failed to protect NEMO-null cells against TNF-α-induced cell death but protected those reconstituted with the NEMO mutant truncated to include only the N-terminal 251 amino acid residues [the NEMO(1-251) mutant]. Taken collectively, our results demonstrate that NEMO is required for modulation of K13-induced genes and the N-terminal 251 amino acids of NEMO are sufficient for supporting K13-induced NF-κB. Finally, the ability of K13 to protect against TNF-α-induced cell death is critically dependent on its ability to interact with NEMO and activate NF-κB. IMPORTANCE Kaposi's sarcoma-associated herpesvirus-encoded vFLIP K13 is believed to protect virally infected cells against death receptor-induced apoptosis and to activate the NF-κB pathway by binding to adaptor protein NEMO/IKKγ. However, whether K13 can also induce gene expression independently of NEMO and the minimum region of NEMO that is sufficient for supporting K13-induced NF-κB remain to be delineated. Furthermore, the contribution of NEMO and NF-κB to the protective effect of K13 against death receptor-induced apoptosis is not clear. We demonstrate that NEMO is required for modulation of K13-induced genes and its N-terminal 251 amino acids are sufficient for supporting K13-induced NF-κB. The ability of K13 to protect against TNF-α-induced cell death is critically dependent on its ability to interact with NEMO and activate NF-κB. Our results suggest that K13-based gene therapy approaches may have utility for the treatment of patients with NEMO mutations and immunodeficiency.
Collapse
|
48
|
Zhi H, Zahoor MA, Shudofsky AMD, Giam CZ. KSHV vCyclin counters the senescence/G1 arrest response triggered by NF-κB hyperactivation. Oncogene 2014; 34:496-505. [PMID: 24469036 PMCID: PMC4112183 DOI: 10.1038/onc.2013.567] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 11/20/2013] [Accepted: 11/29/2013] [Indexed: 12/19/2022]
Abstract
Many oncogenic viruses activate NF-κB as a part of their replicative cycles. We have shown recently that persistent and potentially oncogenic activation of NF-κB by the human T-lymphotropic virus 1 (HTLV-1) oncoprotein Tax immediately triggers a host senescence response mediated by cyclin-dependent kinase inhibitors: p21CIP1/WAF1 (p21) and p27Kip1 (p27) Here we demonstrate that RelA/NF-κB activation by Kaposi sarcoma herpesvirus (KSHV) latency protein vFLIP also leads to p21/p27 up-regulation and G1 cell cycle arrest. Remarkably, KSHV vCyclin, another latency protein co-expressed with vFLIP from a bicistronic latency-specific mRNA, was found to prevent the senescence and G1 arrest induced by HTLV-1 Tax and vFLIP respectively. This is due to the known ability of vCyclin/CDK6 complex to resist p21 and p27 inhibition and cause p27 degradation23. In KSHV-transformed BCBL-1 cells, sustained vFLIP expression with shRNA-mediated vCyclin depletion resulted in G1 arrest. The functional interdependence of vFLIP and vCyclin explains why they are co-translated from the same viral mRNA. Importantly, deregulation of the G1 cyclin-dependent kinase can facilitate chronic IKK/NF-κB activation.
Collapse
Affiliation(s)
- H Zhi
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - M A Zahoor
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - A M D Shudofsky
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - C-Z Giam
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| |
Collapse
|
49
|
Tumour immunogenicity, antigen presentation and immunological barriers in cancer immunotherapy. ACTA ACUST UNITED AC 2014; 2014. [PMID: 24634791 DOI: 10.1155/2014/734515] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since the beginning of the 20th century, scientists have tried to stimulate the anti-tumour activities of the immune system to fight against cancer. However, the scientific effort devoted on the development of cancer immunotherapy has not been translated into the expected clinical success. On the contrary, classical anti-neoplastic treatments such as surgery, radiotherapy and chemotherapy are the first line of treatment. Nevertheless, there is compelling evidence on the immunogenicity of cancer cells, and the capacity of the immune system to expand cancer-specific effector cytotoxic T cells. However, the effective activation of anti-cancer T cell responses strongly depends on efficient tumour antigen presentation from professional antigen presenting cells such as dendritic cells (DCs). Several strategies have been used to boost DC antigen presenting functions, but at the end cancer immunotherapy is not as effective as would be expected according to preclinical models. In this review we comment on these discrepancies, focusing our attention on the contribution of regulatory T cells and myeloid-derived suppressor cells to the lack of therapeutic success of DC-based cancer immunotherapy.
Collapse
|
50
|
Hinz M, Scheidereit C. The IκB kinase complex in NF-κB regulation and beyond. EMBO Rep 2013; 15:46-61. [PMID: 24375677 DOI: 10.1002/embr.201337983] [Citation(s) in RCA: 381] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The IκB kinase (IKK) complex is the signal integration hub for NF-κB activation. Composed of two serine-threonine kinases (IKKα and IKKβ) and the regulatory subunit NEMO (also known as IKKγ), the IKK complex integrates signals from all NF-κB activating stimuli to catalyze the phosphorylation of various IκB and NF-κB proteins, as well as of other substrates. Since the discovery of the IKK complex components about 15 years ago, tremendous progress has been made in the understanding of the IKK architecture and its integration into signaling networks. In addition to the control of NF-κB, IKK subunits mediate the crosstalk with other pathways, thereby extending the complexity of their biological function. This review summarizes recent advances in IKK biology and focuses on emerging aspects of IKK structure, regulation and function.
Collapse
Affiliation(s)
- Michael Hinz
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | |
Collapse
|