1
|
Wild M, Karner D, Eickhoff J, Wagner S, Kicuntod J, Chang W, Barry P, Jonjić S, Lenac Roviš T, Marschall M. Combined Treatment with Host-Directed and Anticytomegaloviral Kinase Inhibitors: Mechanisms, Synergisms and Drug Resistance Barriers. Pharmaceutics 2023; 15:2680. [PMID: 38140021 PMCID: PMC10748244 DOI: 10.3390/pharmaceutics15122680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
Despite the availability of currently approved antiviral drugs, infections with human cytomegalovirus (HCMV) still cause clinically challenging, sometimes life-threatening situations. There is an urgent need for enhanced anti-HCMV drugs that offer improved efficacy, reduced dosages and options for long-term treatment without risk of the development of viral drug resistance. Recently, we reported the pronounced anti-HCMV efficacy of pharmacological inhibitors of cyclin-dependent kinases (CDKs), in particular, the potential of utilizing drug synergies upon combination treatment with inhibitors of host CDKs and the viral CDK-like kinase pUL97 (vCDK/pUL97). Here, we expand this finding by further assessing the in vitro synergistic antiviral interaction between vCDK and CDK inhibitors towards HCMV as well as non-human cytomegaloviruses. An extension of this synergy approach was achieved in vivo by using the recombinant MCMV-UL97/mouse model, confirming the high potential of combination treatment with the clinically approved vCDK inhibitor maribavir (MBV) and the developmental CDK7 inhibitor LDC4297. Moreover, mechanistic aspects of this synergistic drug combination were illustrated on the levels of intracellular viral protein transport and viral genome replication. The analysis of viral drug resistance did not reveal resistance formation in the case of MBV + LDC4297 combination treatment. Spanning various investigational levels, these new results strongly support our concept, employing the great potential of anti-HCMV synergistic drug treatment.
Collapse
Affiliation(s)
- Markus Wild
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| | - Dubravka Karner
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; (D.K.); (S.J.); (T.L.R.)
| | - Jan Eickhoff
- Lead Discovery Center GmbH, Otto-Hahn-Str. 15, 44227 Dortmund, Germany;
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| | - Jintawee Kicuntod
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| | - William Chang
- Department of Medical Microbiology and Immunology, California National Primate Research Center, University of California, 3146 Tupper Hall, 1 Shields Avenue, Davis, CA 95616, USA; (W.C.); (P.B.)
| | - Peter Barry
- Department of Medical Microbiology and Immunology, California National Primate Research Center, University of California, 3146 Tupper Hall, 1 Shields Avenue, Davis, CA 95616, USA; (W.C.); (P.B.)
| | - Stipan Jonjić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; (D.K.); (S.J.); (T.L.R.)
| | - Tihana Lenac Roviš
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; (D.K.); (S.J.); (T.L.R.)
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| |
Collapse
|
2
|
Schütz M, Wangen C, Sommerer M, Kögler M, Eickhoff J, Degenhart C, Klebl B, Naing Z, Egilmezer E, Hamilton ST, Rawlinson WD, Sticht H, Marschall M. Cytomegalovirus cyclin-dependent kinase ortholog vCDK/pUL97 undergoes regulatory interaction with human cyclin H and CDK7 to codetermine viral replication efficiency. Virus Res 2023; 335:199200. [PMID: 37591314 PMCID: PMC10445456 DOI: 10.1016/j.virusres.2023.199200] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/19/2023]
Abstract
Human cytomegalovirus (HCMV) infection is shaped by a tightly regulated interplay between viral and cellular proteins. Distinct kinase activities, such as the viral cyclin-dependent kinase ortholog (vCDK) pUL97 and cellular CDK7 are both crucial for efficient viral replication. Previously, we reported that both kinases, vCDK/pUL97 and CDK7, interact with cyclin H, thereby achieving an enhanced level of kinase activity and overall functionality in viral replication. Here we provide a variety of novel results, as generated on a methodologically extended basis, and present a concept for the codetermination of viral replication efficiency through these kinase activities: (i) cyclin H expression, in various human cell types, is substantially upregulated by strains of HCMV including the clinically relevant HCMV Merlin; (ii) vCDK/pUL97 interacts with human cyclin H in both HCMV-infected and plasmid-transfected cell systems; (iii) a doxycycline-inducible shRNA-dependent knock-down (KD) of cyclin H significantly reduces pUL97 activity (qSox in vitro kinase assay); (iv) accordingly, pUL97 in vitro kinase activity is seen significantly increased upon addition of recombinant cyclin H; (v) as a point of specific importance, human CDK7 activity shows an increase by vCDK/pUL97-mediated trans-stimulation (whereas pUL97 is not stimulated by CDK7); (vi) phosphosite-specific antibodies indicate an upregulated CDK7 phosphorylation upon HCMV infection, as mediated through a pUL97-specific modulatory effect (i.e. shown by pUL97 inhibitor treatment or pUL97-deficient viral mutant); (vii) finally, an efficient KD of cyclin H in primary fibroblasts generally results in an impaired HCMV replication efficiency as measured on protein and genomic levels. These results show evidence for the codetermination of viral replication by vCDK/pUL97, cyclin H and CDK7, thus supporting the specific importance of cyclin H as a central regulatory factor, and suggesting novel targeting options for antiviral drugs.
Collapse
Affiliation(s)
- Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Mona Sommerer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Melanie Kögler
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | | | | | - Bert Klebl
- Lead Discovery Center GmbH, Dortmund, Germany
| | - Zin Naing
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Ece Egilmezer
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Stuart T Hamilton
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - William D Rawlinson
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
| |
Collapse
|
3
|
Liang J, Wu Y, Lan K, Dong C, Wu S, Li S, Zhou HB. Antiviral PROTACs: Opportunity borne with challenge. CELL INSIGHT 2023; 2:100092. [PMID: 37398636 PMCID: PMC10308200 DOI: 10.1016/j.cellin.2023.100092] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 07/04/2023]
Abstract
Proteolysis targeting chimera (PROTAC) degradation of pathogenic proteins by hijacking of the ubiquitin-proteasome-system has become a promising strategy in drug design. The overwhelming advantages of PROTAC technology have ensured a rapid and wide usage, and multiple PROTACs have entered clinical trials. Several antiviral PROTACs have been developed with promising bioactivities against various pathogenic viruses. However, the number of reported antiviral PROTACs is far less than that of other diseases, e.g., cancers, immune disorders, and neurodegenerative diseases, possibly because of the common deficiencies of PROTAC technology (e.g., limited available ligands and poor membrane permeability) plus the complex mechanism involved and the high tendency of viral mutation during transmission and replication, which may challenge the successful development of effective antiviral PROTACs. This review highlights the important advances in this rapidly growing field and critical limitations encountered in developing antiviral PROTACs by analyzing the current status and representative examples of antiviral PROTACs and other PROTAC-like antiviral agents. We also summarize and analyze the general principles and strategies for antiviral PROTAC design and optimization with the intent of indicating the potential strategic directions for future progress.
Collapse
Affiliation(s)
- Jinsen Liang
- Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430071, China
| | - Yihe Wu
- Provincial Key Laboratory of Developmentally Originated Disease, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Chune Dong
- Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430071, China
| | - Shuwen Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Shu Li
- Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430071, China
| | - Hai-Bing Zhou
- Medical Research Institute, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430071, China
- Provincial Key Laboratory of Developmentally Originated Disease, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China
| |
Collapse
|
4
|
Hahn F, Hamilton ST, Wangen C, Wild M, Kicuntod J, Brückner N, Follett JEL, Herrmann L, Kheimar A, Kaufer BB, Rawlinson WD, Tsogoeva SB, Marschall M. Development of a PROTAC-Based Targeting Strategy Provides a Mechanistically Unique Mode of Anti-Cytomegalovirus Activity. Int J Mol Sci 2021; 22:12858. [PMID: 34884662 PMCID: PMC8657773 DOI: 10.3390/ijms222312858] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/24/2021] [Accepted: 11/24/2021] [Indexed: 12/31/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a major pathogenic herpesvirus that is prevalent worldwide and it is associated with a variety of clinical symptoms. Current antiviral therapy options do not fully satisfy the medical needs; thus, improved drug classes and drug-targeting strategies are required. In particular, host-directed antivirals, including pharmaceutical kinase inhibitors, might help improve the drug qualities. Here, we focused on utilizing PROteolysis TArgeting Chimeras (PROTACs), i.e., hetero-bifunctional molecules containing two elements, namely a target-binding molecule and a proteolysis-inducing element. Specifically, a PROTAC that was based on a cyclin-dependent kinase (CDK) inhibitor, i.e., CDK9-directed PROTAC THAL-SNS032, was analyzed and proved to possess strong anti-HCMV AD169-GFP activity, with values of EC50 of 0.030 µM and CC50 of 0.175 µM (SI of 5.8). Comparing the effect of THAL-SNS032 with its non-PROTAC counterpart SNS032, data indicated a 3.7-fold stronger anti-HCMV efficacy. This antiviral activity, as illustrated for further clinically relevant strains of human and murine CMVs, coincided with the mid-nanomolar concentration range necessary for a drug-induced degradation of the primary (CDK9) and secondary targets (CDK1, CDK2, CDK7). In addition, further antiviral activities were demonstrated, such as the inhibition of SARS-CoV-2 replication, whereas other investigated human viruses (i.e., varicella zoster virus, adenovirus type 2, and Zika virus) were found insensitive. Combined, the antiviral quality of this approach is seen in its (i) mechanistic uniqueness; (ii) future options of combinatorial drug treatment; (iii) potential broad-spectrum activity; and (iv) applicability in clinically relevant antiviral models. These novel data are discussed in light of the current achievements of anti-HCMV drug development.
Collapse
Affiliation(s)
- Friedrich Hahn
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (M.W.); (J.K.); (N.B.)
| | - Stuart T. Hamilton
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, Schools of Women’s and Children’s Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2031, Australia; (S.T.H.); (J.E.L.F.); (W.D.R.)
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (M.W.); (J.K.); (N.B.)
| | - Markus Wild
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (M.W.); (J.K.); (N.B.)
| | - Jintawee Kicuntod
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (M.W.); (J.K.); (N.B.)
| | - Nadine Brückner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (M.W.); (J.K.); (N.B.)
| | - Jasmine E. L. Follett
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, Schools of Women’s and Children’s Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2031, Australia; (S.T.H.); (J.E.L.F.); (W.D.R.)
| | - Lars Herrmann
- Institute of Organic Chemistry I, FAU, 91058 Erlangen, Germany; (L.H.); (S.B.T.)
| | - Ahmed Kheimar
- Institute of Virology, Freie Universität Berlin, 14163 Berlin, Germany; (A.K.); (B.B.K.)
| | - Benedikt B. Kaufer
- Institute of Virology, Freie Universität Berlin, 14163 Berlin, Germany; (A.K.); (B.B.K.)
| | - William D. Rawlinson
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, Schools of Women’s and Children’s Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2031, Australia; (S.T.H.); (J.E.L.F.); (W.D.R.)
| | - Svetlana B. Tsogoeva
- Institute of Organic Chemistry I, FAU, 91058 Erlangen, Germany; (L.H.); (S.B.T.)
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (M.W.); (J.K.); (N.B.)
| |
Collapse
|
5
|
Methodological Development of a Multi-Readout Assay for the Assessment of Antiviral Drugs against SARS-CoV-2. PATHOGENS (BASEL, SWITZERLAND) 2021; 10:pathogens10091076. [PMID: 34578109 PMCID: PMC8466411 DOI: 10.3390/pathogens10091076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/30/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023]
Abstract
Currently, human infections with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) are accelerating the ongoing spread of the pandemic. Several innovative types of vaccines have already been developed, whereas effective options of antiviral treatments still await a scientific implementation. The development of novel anti-SARS-CoV-2 drug candidates demands skillful strategies and analysis systems. Promising results have been achieved with first generation direct-acting antivirals targeting the viral polymerase RdRp or the protease 3CLpro. Such recently approved or investigational drugs like remdesivir and GC376 represent a basis for further development and optimization. Here, we establish a multi-readout assay (MRA) system that enables the antiviral assessment and mechanistic characterization of novel test compounds, drug repurposing and combination treatments. Our SARS-CoV-2-specific MRA combines the quantitative measurement of several parameters of virus infection, such as the intracellular production of proteins and genomes, enzymatic activities and virion release, as well as the use of reporter systems. In this regard, the antiviral efficacy of remdesivir and GC376 has been investigated in human Caco-2 cells. The readouts included the use of spike- and double-strand RNA-specific monoclonal antibodies for in-cell fluorescence imaging, a newly generated recombinant SARS-CoV-2 reporter virus d6YFP, the novel 3CLpro-based FRET CFP::YFP and the previously reported FlipGFP reporter assays, as well as viral genome-specific RT-qPCR. The data produced by our MRA confirm the high antiviral potency of these two drugs in vitro. Combined, this MRA approach may be applied for broader analyses of SARS-CoV-2-specific antivirals, including compound screenings and the characterization of selected drug candidates.
Collapse
|
6
|
Functional Relevance of the Interaction between Human Cyclins and the Cytomegalovirus-Encoded CDK-Like Protein Kinase pUL97. Viruses 2021; 13:v13071248. [PMID: 34198986 PMCID: PMC8310212 DOI: 10.3390/v13071248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 02/07/2023] Open
Abstract
The replication of human cytomegalovirus (HCMV) is characterized by a complex network of virus–host interaction. This involves the regulatory viral protein kinase pUL97, which represents a viral cyclin-dependent kinase ortholog (vCDK) combining typical structural and functional features of host CDKs. Notably, pUL97 interacts with the three human cyclin types T1, H and B1, whereby the binding region of cyclin T1 and the region conferring oligomerization of pUL97 were both assigned to amino acids 231–280. Here, we addressed the question of whether recombinant HCMVs harboring deletions in this region were impaired in cyclin interaction, kinase functionality or viral replication. To this end, recombinant HCMVs were generated by traceless BACmid mutagenesis and were phenotypically characterized using a methodological platform based on qPCR, coimmunoprecipitation, in vitro kinase assay (IVKA), Phos-tag Western blot and confocal imaging analysis. Combined data illustrate the following: (i) infection kinetics of all three recombinant HCMVs, i.e., ORF-UL97 ∆231–255, ∆256–280 and ∆231–280, showed impaired replication efficiency compared to the wild type, amongst which the largest deletion exhibited the most pronounced defect; (ii) specifically, this mutant ∆231–280 showed a loss of interaction with cyclin T1, as demonstrated by CoIP and confocal imaging; (iii) IVKA and Phos-tag analyses revealed strongly affected kinase activity for ∆231–280, with strong impairment of both autophosphorylation and substrate phosphorylation, but less pronounced impairments for ∆231–255 and ∆256–280; and (iv) a bioinformatic assessment of the pUL97–cyclin T1 complex led to the refinement of our current binding model. Thus, the results provide initial evidence for the functional importance of the pUL97–cyclin interaction concerning kinase activity and viral replication fitness.
Collapse
|
7
|
Marschall M, Strojan H, Kiener R, Wangen C, Sonntag E, Müller R, Zeitträger I, Wagner S, Stamminger T, Milbradt J, Behrends U, Körber N, Bauer T, Schrödel S, Thirion C, Wagner R, Hutterer C. Differential upregulation of host cell protein kinases by the replication of α-, β- and γ-herpesviruses provides a signature of virus-specific signalling. J Gen Virol 2020; 101:284-289. [PMID: 31958050 DOI: 10.1099/jgv.0.001370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Infections with human herpesviruses share several molecular characteristics, but the diversified medical outcomes are distinct to viral subfamilies and species. Notably, both clinical and molecular correlates of infection are a challenging field and distinct patterns of virus-host interaction have rarely been defined; this study therefore focuses on the search for virus-specific molecular indicators. As previous studies have demonstrated the impact of herpesvirus infections on changes in host signalling pathways, we illustrate virus-modulated expression levels of individual cellular protein kinases. Current data reveal (i) α-, β- and γ-herpesvirus-specific patterns of kinase modulation as well as (ii) differential levels of up-/downregulated kinase expression and phosphorylation, which collectively suggest (iii) defined signalling patterns specific for the various viruses (VSS) that may prove useful for defining molecular indicators. Combined, the study confirms the correlation between herpesviral replication and modulation of signalling kinases, possibly exploitable for the in vitro characterization of viral infections.
Collapse
Affiliation(s)
- Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Hanife Strojan
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Richard Kiener
- Institute for Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Eric Sonntag
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Regina Müller
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Isabel Zeitträger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | | | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Uta Behrends
- German Center for Infection Research (DZIF), Munich, Germany
- Research Unit Gene Vectors, Helmholtz Zentrum München/TUM, Munich, Germany
- Children's Hospital Schwabing, Technische Universität München (TUM), Munich, Germany
| | - Nina Körber
- Institute of Virology, Helmholtz Zentrum München/TUM, Munich, Germany
| | - Tanja Bauer
- Institute of Virology, Helmholtz Zentrum München/TUM, Munich, Germany
- German Center for Infection Research (DZIF), Munich, Germany
| | | | | | - Ralf Wagner
- Institute for Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Corina Hutterer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| |
Collapse
|
8
|
Wang YQ, Zhao XY. Human Cytomegalovirus Primary Infection and Reactivation: Insights From Virion-Carried Molecules. Front Microbiol 2020; 11:1511. [PMID: 32765441 PMCID: PMC7378892 DOI: 10.3389/fmicb.2020.01511] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/10/2020] [Indexed: 12/12/2022] Open
Abstract
Human cytomegalovirus (HCMV), a ubiquitous beta-herpesvirus, is able to establish lifelong latency after initial infection. Periodical reactivation occurs after immunosuppression, remaining a major cause of death in immunocompromised patients. HCMV has to reach a structural and functional balance with the host at its earliest entry. Virion-carried mediators are considered to play pivotal roles in viral adaptation into a new cellular environment upon entry. Additionally, one clear difference between primary infection and reactivation is the idea that virion-packaged factors are already formed such that those molecules can be used swiftly by the virus. In contrast, virion-carried mediators have to be transcribed and translated; thus, they are not readily available during reactivation. Hence, understanding virion-carried molecules helps to elucidate HCMV reactivation. In this article, the impact of virion-packaged molecules on viral structure, biological behavior, and viral life cycle will be reviewed.
Collapse
Affiliation(s)
- Yu-Qing Wang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Key Laboratory of Hematopoietic Stem Cell Transplantation, Beijing, China.,PKU-THU Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Xiang-Yu Zhao
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Key Laboratory of Hematopoietic Stem Cell Transplantation, Beijing, China
| |
Collapse
|
9
|
Couté Y, Kraut A, Zimmermann C, Büscher N, Hesse AM, Bruley C, De Andrea M, Wangen C, Hahn F, Marschall M, Plachter B. Mass Spectrometry-Based Characterization of the Virion Proteome, Phosphoproteome, and Associated Kinase Activity of Human Cytomegalovirus. Microorganisms 2020; 8:microorganisms8060820. [PMID: 32486127 PMCID: PMC7357008 DOI: 10.3390/microorganisms8060820] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/28/2020] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
The assembly of human cytomegalovirus (HCMV) virions is an orchestrated process that requires, as an essential prerequisite, the complex crosstalk between viral structural proteins. Currently, however, the mechanisms governing the successive steps in the constitution of virion protein complexes remain elusive. Protein phosphorylation is a key regulator determining the sequential changes in the conformation, binding, dynamics, and stability of proteins in the course of multiprotein assembly. In this review, we present a comprehensive map of the HCMV virion proteome, including a refined view on the virion phosphoproteome, based on previous publications supplemented by new results. Thus, a novel dataset of viral and cellular proteins contained in HCMV virions is generated, providing a basis for future analyses of individual phosphorylation steps and sites involved in the orchestrated assembly of HCMV virion-specific multiprotein complexes. Finally, we present the current knowledge on the activity of pUL97, the HCMV-encoded and virion-associated kinase, in phosphorylating viral and host proteins.
Collapse
Affiliation(s)
- Yohann Couté
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
- Correspondence: (Y.C.); (B.P.); Tel.: +33-4-38789461 (Y.C.); +49-6131-179232 (B.P.)
| | - Alexandra Kraut
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
| | - Christine Zimmermann
- Institute for Virology and Forschungszentrum für Immuntherapie, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany; (C.Z.); (N.B.)
| | - Nicole Büscher
- Institute for Virology and Forschungszentrum für Immuntherapie, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany; (C.Z.); (N.B.)
| | - Anne-Marie Hesse
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
| | - Christophe Bruley
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
| | - Marco De Andrea
- Department of Public Health and Pediatric Sciences, Turin Medical School, University of Turin, 10126 Turin, and CAAD – Center for Translational Research on Autoimmune and Allergic Disease, Novara Medical School, 28100 Novara, Italy;
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (F.H.); (M.M.)
| | - Friedrich Hahn
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (F.H.); (M.M.)
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (F.H.); (M.M.)
| | - Bodo Plachter
- Institute for Virology and Forschungszentrum für Immuntherapie, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany; (C.Z.); (N.B.)
- Correspondence: (Y.C.); (B.P.); Tel.: +33-4-38789461 (Y.C.); +49-6131-179232 (B.P.)
| |
Collapse
|
10
|
Schütz M, Thomas M, Wangen C, Wagner S, Rauschert L, Errerd T, Kießling M, Sticht H, Milbradt J, Marschall M. The peptidyl-prolyl cis/trans isomerase Pin1 interacts with three early regulatory proteins of human cytomegalovirus. Virus Res 2020; 285:198023. [PMID: 32428517 DOI: 10.1016/j.virusres.2020.198023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/17/2020] [Accepted: 05/13/2020] [Indexed: 12/19/2022]
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous human pathogen of high clinical relevance. Despite intensive research of virus-host interaction, crucial details still remain unknown. In this study, the role of the cellular peptidyl-prolyl cis/trans isomerase Pin1 during HCMV infection was investigated. Pin1 is able to recognize phosphorylated serine/threonine-proline motifs and regulates the structural conformation, stability and function of its substrates. Concerning HCMV replication, our recent studies revealed that Pin1 plays an important role in viral nuclear egress by contributing to the depletion of the nuclear lamina at distinct sites through the cis/trans conversion of lamin proteins. Here, novel data illustrate the HCMV-induced upregulation of Pin1 including various cell types being permissive, semi-permissive or non-permissive for productive HCMV replication. Addressing the question of functional impact, Pin1 knock-out (KO) did not show a measurable effect on viral protein expression, at least when assessed by Western blot analysis. Applying highly sensitive methods of qPCR and plaque titration, a pharmacological inhibition of Pin1 activity, however, led to a significant decrease of viral genome equivalents and production of infectious virus, respectively. When focusing on the identification of viral proteins interacting with Pin1 by various coimmunoprecipitation (CoIP) settings, we obtained positive signals for (i) the core nuclear egress complex protein pUL50, (ii) the viral mRNA export factor pUL69 and (iii) the viral DNA polymerase processivity factor pUL44. Confocal immunofluorescence analysis focusing on partial colocalization between Pin1 and the coexpressed viral proteins pUL50, pUL69 or pUL44, respectively, was consistent with the CoIP experiments. Mapping experiments, using transient expression constructs for a series of truncated protein versions and specific replacement mutants, revealed a complex pattern of Pin1 interaction with these three early regulatory HCMV proteins. Data suggest a combination of different modes of Pin1 interactions, involving both classical phosphorylation-dependent Pin1 binding motifs and additional phosphorylation-independent binding sites. Combined, these results support the concept that Pin1 may play an important role in several stages of HCMV infection, thus determining viral replicative efficiency.
Collapse
Affiliation(s)
- Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Marco Thomas
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Luisa Rauschert
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Theresa Errerd
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Melissa Kießling
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU, Erlangen, Germany.
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen- Nürnberg (FAU), Erlangen, Germany.
| |
Collapse
|
11
|
The Cytomegalovirus Protein Kinase pUL97:Host Interactions, Regulatory Mechanisms and Antiviral Drug Targeting. Microorganisms 2020; 8:microorganisms8040515. [PMID: 32260430 PMCID: PMC7232230 DOI: 10.3390/microorganisms8040515] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 12/25/2022] Open
Abstract
Human cytomegalovirus (HCMV) expresses a variety of viral regulatory proteins that undergo close interaction with host factors including viral-cellular multiprotein complexes. The HCMV protein kinase pUL97 represents a viral cyclin-dependent kinase ortholog (vCDK) that determines the efficiency of HCMV replication via phosphorylation of viral and cellular substrates. A hierarchy of functional importance of individual pUL97-mediated phosphorylation events has been discussed; however, the most pronounced pUL97-dependent phenotype could be assigned to viral nuclear egress, as illustrated by deletion of the UL97 gene or pharmacological pUL97 inhibition. Despite earlier data pointing to a cyclin-independent functionality, experimental evidence increasingly emphasized the role of pUL97-cyclin complexes. Consequently, the knowledge about pUL97 involvement in host interaction, viral nuclear egress and additional replicative steps led to the postulation of pUL97 as an antiviral target. Indeed, validation experiments in vitro and in vivo confirmed the sustainability of this approach. Consequently, current investigations of pUL97 in antiviral treatment go beyond the known pUL97-mediated ganciclovir prodrug activation and henceforward include pUL97-specific kinase inhibitors. Among a number of interesting small molecules analyzed in experimental and preclinical stages, maribavir is presently investigated in clinical studies and, in the near future, might represent a first kinase inhibitor applied in the field of antiviral therapy.
Collapse
|
12
|
Phosphosite Analysis of the Cytomegaloviral mRNA Export Factor pUL69 Reveals Serines with Critical Importance for Recruitment of Cellular Proteins Pin1 and UAP56/URH49. J Virol 2020; 94:JVI.02151-19. [PMID: 31969433 DOI: 10.1128/jvi.02151-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 01/13/2020] [Indexed: 01/04/2023] Open
Abstract
Human cytomegalovirus (HCMV) encodes the viral mRNA export factor pUL69, which facilitates the cytoplasmic accumulation of mRNA via interaction with the cellular RNA helicase UAP56 or URH49. We reported previously that pUL69 is phosphorylated by cellular CDKs and the viral CDK-like kinase pUL97. Here, we set out to identify phosphorylation sites within pUL69 and to characterize their importance. Mass spectrometry-based phosphosite mapping of pUL69 identified 10 serine/threonine residues as phosphoacceptors. Surprisingly, only a few of these sites localized to the N terminus of pUL69, which could be due to the presence of additional posttranslational modifications, like arginine methylation. As an alternative approach, pUL69 mutants with substitutions of putative phosphosites were analyzed by Phos-tag SDS-PAGE. This demonstrated that serines S46 and S49 serve as targets for phosphorylation by pUL97. Furthermore, we provide evidence that phosphorylation of these serines mediates cis/trans isomerization by the prolyl isomerase Pin1, thus forming a functional Pin1 binding motif. Surprisingly, while abrogation of the Pin1 motif did not affect the replication of recombinant cytomegaloviruses, mutation of serines next to the interaction site for UAP56/URH49 strongly decreased viral replication. This was correlated with a loss of UAP56/URH49 recruitment. Intriguingly, the critical serines S13 and S15 were located within a sequence resembling the UAP56 binding motif (UBM) of cellular mRNA adaptor proteins like REF and UIF. We propose that betaherpesviral mRNA export factors have evolved an extended UAP56/URH49 recognition sequence harboring phosphorylation sites to increase their binding affinities. This may serve as a strategy to successfully compete with cellular mRNA adaptor proteins for binding to UAP56/URH49.IMPORTANCE The multifunctional regulatory protein pUL69 of human cytomegalovirus acts as a viral RNA export factor with a critical role in efficient replication. Here, we identify serine/threonine phosphorylation sites for cellular and viral kinases within pUL69. We demonstrate that the pUL97/CDK phosphosites within alpha-helix 2 of pUL69 are crucial for its cis/trans isomerization by the cellular protein Pin1. Thus, we identified pUL69 as the first HCMV-encoded protein that is phosphorylated by cellular and viral serine/threonine kinases in order to serve as a substrate for Pin1. Furthermore, our study revealed that betaherpesviral mRNA export proteins contain extended binding motifs for the cellular mRNA adaptor proteins UAP56/URH49 harboring phosphorylated serines that are critical for efficient viral replication. Knowledge of the phosphorylation sites of pUL69 and the processes regulated by these posttranslational modifications is important in order to develop antiviral strategies based on a specific interference with pUL69 phosphorylation.
Collapse
|
13
|
Steingruber M, Keller L, Socher E, Ferre S, Hesse AM, Couté Y, Hahn F, Büscher N, Plachter B, Sticht H, Marschall M. Cyclins B1, T1, and H differ in their molecular mode of interaction with cytomegalovirus protein kinase pUL97. J Biol Chem 2019; 294:6188-6203. [PMID: 30782840 DOI: 10.1074/jbc.ra118.007049] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/08/2019] [Indexed: 12/19/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a common β-herpesvirus causing life-long latent infections. HCMV replication interferes with cell cycle regulation in host cells because the HCMV-encoded cyclin-dependent kinase (CDK) ortholog pUL97 extensively phosphorylates the checkpoint regulator retinoblastoma protein. pUL97 also interacts with cyclins B1, T1, and H, and recent findings have strongly suggested that these interactions influence pUL97 substrate recognition. Interestingly, here we detected profound mechanistic differences among these pUL97-cyclin interactions. Our study revealed the following. (i) pUL97 interacts with cyclins B1 and H in a manner dependent on pUL97 activity and HCMV-specific cyclin modulation, respectively. (ii) The phosphorylated state of both proteins is an important determinant of the pUL97-cyclin B1 interaction. (iii) Activated phospho-Thr-315 cyclin H is up-regulated during HCMV replication. (iv) Thr-315 phosphorylation is independent of intracellular pUL97 or CDK7 activity. (v) pUL97-mediated in vitro phosphorylation is detectable for cyclin B1 but not H. (vi) Mutual transphosphorylation between pUL97 and CDK7 is not detectable, and an MS-based phosphosite analysis indicated that pUL97 might unexpectedly not be phosphorylated in its T-loop. (vii) The binary complexes pUL97-cyclin H and CDK7-cyclin H as well as the ternary complex pUL97-cyclin-H-CDK7 are detectable in an assembly-based CoIP approach. (viii) pUL97 self-interaction can be bridged by the transcriptional cyclins T1 or H but not by the classical cell cycle-regulating B1 cyclin. Combined, our findings unravel a number of cyclin type-specific differences in pUL97 interactions and suggest a multifaceted regulatory impact of cyclins on HCMV replication.
Collapse
Affiliation(s)
- Mirjam Steingruber
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany.
| | - Lena Keller
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany
| | - Eileen Socher
- Division of Bioinformatics, Institute of Biochemistry Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Sabrina Ferre
- the Université Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France
| | - Anne-Marie Hesse
- the Université Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France
| | - Yohann Couté
- the Université Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France
| | - Friedrich Hahn
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany
| | - Nicole Büscher
- the Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany
| | - Bodo Plachter
- the Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Manfred Marschall
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany.
| |
Collapse
|
14
|
The ICP27 Homology Domain of the Human Cytomegalovirus Protein UL69 Adopts a Dimer-of-Dimers Structure. mBio 2018; 9:mBio.01112-18. [PMID: 29921674 PMCID: PMC6016253 DOI: 10.1128/mbio.01112-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The UL69 protein from human cytomegalovirus (HCMV) is a multifunctional regulatory protein and a member of the ICP27 protein family conserved throughout herpesviruses. UL69 plays many roles during productive infection, including the regulation of viral gene expression, nuclear export of intronless viral RNAs, and control of host cell cycle progression. Throughout the ICP27 protein family, an ability to self-associate is correlated with the functions of these proteins in transactivating certain viral genes. Here, we determined the domain boundaries of a globular ICP27 homology domain of UL69, which mediates self-association, and characterized the oligomeric state of the isolated domain. Size exclusion chromatography coupled with multiangle light scattering (SEC-MALS) revealed that residues 200 to 540 form a stable homo-tetramer, whereas a shorter region comprising residues 248 to 536 forms a homo-dimer. Structural analysis of the UL69 tetramer by transmission electron microscopy (TEM) revealed a dimer-of-dimers three-dimensional envelope with bridge features likely from a region of the protein unique to betaherpesviruses. The data provide a structural template for tetramerization and improve our understanding of the structural diversity and features necessary for self-association within UL69 and the ICP27 family. Human cytomegalovirus (HCMV) infection is widespread in the human population but typically remains dormant in an asymptomatic latent state. HCMV causes disease in neonates and adults with suppressed or impaired immune function, as the virus is activated into a lytic state. All species of herpesvirus express a protein from the ICP27 family which functions as a posttranscriptional activator in the lytic state. In HCMV, this protein is called UL69. The region of sequence conservation in the ICP27 family is a folded domain that mediates protein interactions, including self-association and functions in transactivation. All members thus far analyzed homo-dimerize, with the exception of UL69, which forms higher-order oligomers. Here, we use biochemical and structural data to reveal that UL69 forms stable tetramers composed of a dimer of dimers and determine a region essential for cross-dimer stabilization.
Collapse
|
15
|
Proteomic Interaction Patterns between Human Cyclins, the Cyclin-Dependent Kinase Ortholog pUL97 and Additional Cytomegalovirus Proteins. Viruses 2016; 8:v8080219. [PMID: 27548200 PMCID: PMC4997581 DOI: 10.3390/v8080219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 08/02/2016] [Indexed: 01/13/2023] Open
Abstract
The human cytomegalovirus (HCMV)-encoded cyclin-dependent kinase (CDK) ortholog pUL97 associates with human cyclin B1 and other types of cyclins. Here, the question was addressed whether cyclin interaction of pUL97 and additional viral proteins is detectable by mass spectrometry-based approaches. Proteomic data were validated by coimmunoprecipitation (CoIP), Western blot, in vitro kinase and bioinformatic analyses. Our findings suggest that: (i) pUL97 shows differential affinities to human cyclins; (ii) pUL97 inhibitor maribavir (MBV) disrupts the interaction with cyclin B1, but not with other cyclin types; (iii) cyclin H is identified as a new high-affinity interactor of pUL97 in HCMV-infected cells; (iv) even more viral phosphoproteins, including all known substrates of pUL97, are detectable in the cyclin-associated complexes; and (v) a first functional validation of pUL97-cyclin B1 interaction, analyzed by in vitro kinase assay, points to a cyclin-mediated modulation of pUL97 substrate preference. In addition, our bioinformatic analyses suggest individual, cyclin-specific binding interfaces for pUL97-cyclin interaction, which could explain the different strengths of interactions and the selective inhibitory effect of MBV on pUL97-cyclin B1 interaction. Combined, the detection of cyclin-associated proteins in HCMV-infected cells suggests a complex pattern of substrate phosphorylation and a role of cyclins in the fine-modulation of pUL97 activities.
Collapse
|