1
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Yang J, Cassel J, Boyle BC, Oppong D, Ahn YH, Weiser BP. A homogeneous time-resolved fluorescence screen to identify SIRT2 deacetylase and defatty-acylase inhibitors. PLoS One 2024; 19:e0305000. [PMID: 38913635 PMCID: PMC11195995 DOI: 10.1371/journal.pone.0305000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/21/2024] [Indexed: 06/26/2024] Open
Abstract
Human sirtuin-2 (SIRT2) has emerged as an attractive drug target for a variety of diseases. The enzyme is a deacylase that can remove chemically different acyl modifications from protein lysine residues. Here, we developed a high-throughput screen based on a homogeneous time-resolved fluorescence (HTRF) binding assay to identify inhibitors of SIRT2's demyristoylase activity, which is uncommon among many ligands that only affect its deacetylase activity. From a test screen of 9600 compounds, we identified a small molecule that inhibited SIRT2's deacetylase activity (IC50 = 7 μM) as well as its demyristoylase activity (IC50 = 37 μM). The inhibitor was composed of two small fragments that independently inhibited SIRT2: a halogenated phenol fragment inhibited its deacetylase activity, and a tricyclic thiazolobenzimidazole fragment inhibited its demyristoylase activity. The high-throughput screen also detected multiple deacetylase-specific SIRT2 inhibitors.
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Affiliation(s)
- Jie Yang
- Department of Molecular Biology, Rowan-Virtua School of Translational Biomedical Engineering & Sciences, Rowan University, Stratford, New Jersey, United States of America
- Department of Molecular Biology, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, United States of America
| | - Joel Cassel
- Molecular Screening & Protein Expression Facility, Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Brian C. Boyle
- Department of Molecular Biology, Rowan-Virtua School of Translational Biomedical Engineering & Sciences, Rowan University, Stratford, New Jersey, United States of America
- Department of Molecular Biology, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, United States of America
- Department of Biomedical Engineering, Rowan-Virtua School of Translational Biomedical Engineering & Sciences, Rowan University, Glassboro, New Jersey, United States of America
| | - Daniel Oppong
- Department of Chemistry, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Young-Hoon Ahn
- Department of Chemistry, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Brian P. Weiser
- Department of Molecular Biology, Rowan-Virtua School of Translational Biomedical Engineering & Sciences, Rowan University, Stratford, New Jersey, United States of America
- Department of Molecular Biology, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, United States of America
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2
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Hayran AB, Liabakk NB, Aas PA, Kusnierczyk A, Vågbø CB, Sarno A, Iveland TS, Chawla K, Zahn A, Di Noia JM, Slupphaug G, Kavli B. RPA guides UNG to uracil in ssDNA to facilitate antibody class switching and repair of mutagenic uracil at the replication fork. Nucleic Acids Res 2024; 52:784-800. [PMID: 38000394 PMCID: PMC10810282 DOI: 10.1093/nar/gkad1115] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 10/27/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) interacts with replication protein A (RPA), the major ssDNA-binding protein, to promote deamination of cytosine to uracil in transcribed immunoglobulin (Ig) genes. Uracil-DNA glycosylase (UNG) acts in concert with AID during Ig diversification. In addition, UNG preserves genome integrity by base-excision repair (BER) in the overall genome. How UNG is regulated to support both mutagenic processing and error-free repair remains unknown. UNG is expressed as two isoforms, UNG1 and UNG2, which both contain an RPA-binding helix that facilitates uracil excision from RPA-coated ssDNA. However, the impact of this interaction in antibody diversification and genome maintenance has not been investigated. Here, we generated B-cell clones with targeted mutations in the UNG RPA-binding motif, and analysed class switch recombination (CSR), mutation frequency (5' Ig Sμ), and genomic uracil in clones representing seven Ung genotypes. We show that the UNG:RPA interaction plays a crucial role in both CSR and repair of AID-induced uracil at the Ig loci. By contrast, the interaction had no significant impact on total genomic uracil levels. Thus, RPA coordinates UNG during CSR and pre-replicative repair of mutagenic uracil in ssDNA but is not essential in post-replicative and canonical BER of uracil in dsDNA.
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Affiliation(s)
- Abdul B Hayran
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Nina B Liabakk
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Per A Aas
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Anna Kusnierczyk
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- PROMEC - Proteomics and Modomics Experimental Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Cathrine B Vågbø
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- PROMEC - Proteomics and Modomics Experimental Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Antonio Sarno
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Tobias S Iveland
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- Cancer Clinic, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Konika Chawla
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- BioCore - Bioinformatics Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Astrid Zahn
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Javier M Di Noia
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
- Département of Médicine, Université de Montréal H3C 3J7 Montréal, Québec, Canada
| | - Geir Slupphaug
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- PROMEC - Proteomics and Modomics Experimental Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
- Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Bodil Kavli
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
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3
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Yang J, Nicely NI, Weiser BP. Effects of Dimerization on the Deacylase Activities of Human SIRT2. Biochemistry 2023; 62:3383-3395. [PMID: 37966275 PMCID: PMC10702427 DOI: 10.1021/acs.biochem.3c00381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/05/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023]
Abstract
Human sirtuin isoform 2 (SIRT2) is an NAD+-dependent enzyme that functions as a lysine deacetylase and defatty-acylase. Here, we report that SIRT2 readily dimerizes in solution and in cells and that dimerization affects its ability to remove different acyl modifications from substrates. Dimerization of recombinant SIRT2 was revealed with analytical size exclusion chromatography and chemical cross-linking. Dimerized SIRT2 dissociates into monomers upon binding long fatty acylated substrates (decanoyl-, dodecanoyl-, and myristoyl-lysine). However, we did not observe dissociation of dimeric SIRT2 in the presence of acetyl-lysine. Analysis of X-ray crystal structures led us to discover a SIRT2 double mutant (Q142A/E340A) that is impaired in its ability to dimerize, which was confirmed with chemical cross-linking and in cells with a split-GFP approach. In enzyme assays, the SIRT2(Q142A/E340A) mutant had normal defatty-acylase activity and impaired deacetylase activity compared with the wild-type protein. These results indicate that dimerization is essential for optimal SIRT2 function as a deacetylase. Moreover, we show that SIRT2 dimers can be dissociated by a deacetylase and defatty-acylase inhibitor, ascorbyl palmitate. Our finding that its oligomeric state can affect the acyl substrate selectivity of SIRT2 is a novel mode of activity regulation by the enzyme that can be altered genetically or pharmacologically.
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Affiliation(s)
- Jie Yang
- Department
of Molecular Biology, Rowan University School
of Osteopathic Medicine, Stratford, New Jersey 08084, United States
| | - Nathan I. Nicely
- Department
of Pharmacology, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | - Brian P. Weiser
- Department
of Molecular Biology, Rowan University School
of Osteopathic Medicine, Stratford, New Jersey 08084, United States
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4
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Abbaraju VD, Robinson TL, Weiser BP. Modeling Biphasic, Non-Sigmoidal Dose-Response Relationships: Comparison of Brain-Cousens and Cedergreen Models for a Biochemical Dataset. ARXIV 2023:arXiv:2308.08618v1. [PMID: 37645052 PMCID: PMC10462167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Biphasic, non-sigmoidal dose-response relationships are frequently observed in biochemistry and pharmacology, but they are not always analyzed with appropriate statistical methods. Here, we examine curve fitting methods for "hormetic" dose-response relationships where low and high doses of an effector produce opposite responses. We provide the full dataset used for modeling, and we provide the code for analyzing the dataset in SAS using two established mathematical models of hormesis, the Brain-Cousens model and the Cedergreen model. We show how to obtain and interpret curve parameters such as the ED50 that arise from modeling, and we discuss how curve parameters might change in a predictable manner when the conditions of the dose-response assay are altered. In addition to modeling the raw dataset that we provide, we also model the dataset after applying common normalization techniques, and we indicate how this affects the parameters that are associated with the fit curves. The Brain-Cousens and Cedergreen models that we used for curve fitting were similarly effective at capturing quantitative information about the biphasic dose-response relationships.
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Affiliation(s)
- Venkat D. Abbaraju
- Virginia Commonwealth University School of Medicine, Richmond, VA 23298 (USA)
| | - Tamaraty L. Robinson
- Rowan-Virtua School of Translational Biomedical Engineering & Sciences (Rowan University), Department of Molecular Biology, Stratford, NJ 08084 (USA)
| | - Brian P. Weiser
- Rowan-Virtua School of Translational Biomedical Engineering & Sciences (Rowan University), Department of Molecular Biology, Stratford, NJ 08084 (USA)
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5
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Greenwood SN, Kulkarni RS, Mikhail M, Weiser BP. Replication Protein A Enhances Kinetics of Uracil DNA Glycosylase on ssDNA and Across DNA Junctions: Explored with a DNA Repair Complex Produced with SpyCatcher/SpyTag Ligation. Chembiochem 2023; 24:e202200765. [PMID: 36883884 PMCID: PMC10267839 DOI: 10.1002/cbic.202200765] [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: 12/22/2022] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 03/09/2023]
Abstract
DNA repair proteins participate in extensive protein-protein interactions that promote the formation of DNA repair complexes. To understand how complex formation affects protein function during base excision repair, we used SpyCatcher/SpyTag ligation to produce a covalent complex between human uracil DNA glycosylase (UNG2) and replication protein A (RPA). Our covalent "RPA-Spy-UNG2" complex could identify and excise uracil bases in duplex areas next to ssDNA-dsDNA junctions slightly faster than the wild-type proteins, but this was highly dependent on DNA structure, as the turnover of the RPA-Spy-UNG2 complex slowed at DNA junctions where RPA tightly engaged long ssDNA sections. Conversely, the enzymes preferred uracil sites in ssDNA where RPA strongly enhanced uracil excision by UNG2 regardless of ssDNA length. Finally, RPA was found to promote UNG2 excision of two uracil sites positioned across a ssDNA-dsDNA junction, and dissociation of UNG2 from RPA enhanced this process. Our approach of ligating together RPA and UNG2 to reveal how complex formation affects enzyme function could be applied to examine other assemblies of DNA repair proteins.
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Affiliation(s)
- Sharon N Greenwood
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Rashmi S Kulkarni
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Michel Mikhail
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
- Department of Internal Medicine, Newark Beth Israel Medical Center, Newark, NJ 07112, USA
| | - Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
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6
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Kulkarni RS, Greenwood SN, Weiser BP. Assay design for analysis of human uracil DNA glycosylase. Methods Enzymol 2022; 679:343-362. [PMID: 36682870 DOI: 10.1016/bs.mie.2022.07.033] [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] [Indexed: 01/25/2023]
Abstract
Human uracil DNA glycosylase (UNG2) is an enzyme whose primary function is to remove uracil bases from genomic DNA. UNG2 activity is critical when uracil bases are elevated in DNA during class switch recombination and somatic hypermutation, and additionally, UNG2 affects the efficacy of thymidylate synthase inhibitors that increase genomic uracil levels. Here, we summarize the enzymatic properties of UNG2 and its mitochondrial analog UNG1. To facilitate studies on the activity of these highly conserved proteins, we discuss three fluorescence-based enzyme assays that have informed much of our understanding on UNG2 function. The assays use synthetic DNA oligonucleotide substrates with uracil bases incorporated in the DNA, and the substrates can be single-stranded, double-stranded, or form other structures such as DNA hairpins or junctions. The fluorescence signal reporting uracil base excision by UNG2 is detected in different ways: (1) Excision of uracil from end-labeled oligonucleotides is measured by visualizing UNG2 reaction products with denaturing PAGE; (2) Uracil excision from dsDNA substrates is detected in solution by base pairing uracil with 2-aminopurine, whose intrinsic fluorescence is enhanced upon uracil excision; or (3) UNG2 excision of uracil from a hairpin molecular beacon substrate changes the structure of the substrate and turns on fluorescence by relieving a fluorescence quench. In addition to their utility in characterizing UNG2 properties, these assays are being adapted to discover inhibitors of the enzyme and to determine how protein-protein interactions affect UNG2 function.
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Affiliation(s)
- Rashmi S Kulkarni
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, United States
| | - Sharon N Greenwood
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, United States
| | - Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, United States.
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7
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Bae H, Viennet T, Park E, Chu N, Salguero A, Eck MJ, Arthanari H, Cole PA. PH domain-mediated autoinhibition and oncogenic activation of Akt. eLife 2022; 11:80148. [PMID: 35968932 PMCID: PMC9417420 DOI: 10.7554/elife.80148] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Akt is a Ser/Thr protein kinase that plays a central role in metabolism and cancer. Regulation of Akt’s activity involves an autoinhibitory intramolecular interaction between its pleckstrin homology (PH) domain and its kinase domain that can be relieved by C-tail phosphorylation. PH domain mutant E17K Akt is a well-established oncogene. Previously, we reported that the conformation of autoinhibited Akt may be shifted by small molecule allosteric inhibitors limiting the mechanistic insights from existing X-ray structures that have relied on such compounds (Chu et al., 2020). Here, we discover unexpectedly that a single mutation R86A Akt exhibits intensified autoinhibitory features with enhanced PH domain-kinase domain affinity. Structural and biochemical analysis uncovers the importance of a key interaction network involving Arg86, Glu17, and Tyr18 that controls Akt conformation and activity. Our studies also shed light on the molecular basis for E17K Akt activation as an oncogenic driver.
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Affiliation(s)
- Hwan Bae
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Thibault Viennet
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, United States
| | - Eunyoung Park
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, United States
| | - Nam Chu
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, United States
| | - Antonieta Salguero
- Department of Medicine, Brigham and Women's Hospital, Boston, United States
| | - Michael J Eck
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, United States
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Philip A Cole
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
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8
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Greenwood SN, Belz RG, Weiser BP. A Conserved Mechanism for Hormesis in Molecular Systems. Dose Response 2022; 20:15593258221109335. [PMID: 35936511 PMCID: PMC9350523 DOI: 10.1177/15593258221109335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/06/2022] [Indexed: 11/25/2022]
Abstract
Hormesis refers to dose-response phenomena where low dose treatments elicit a
response that is opposite the response observed at higher doses. Hormetic
dose-response relationships have been observed throughout all of biology, but
the underlying determinants of many reported hormetic dose-responses have not
been identified. In this report, we describe a conserved mechanism for hormesis
on the molecular level where low dose treatments enhance a response that becomes
reduced at higher doses. The hormetic mechanism relies on the ability of protein
homo-multimers to simultaneously interact with a substrate and a competitor on
different subunits at low doses of competitor. In this case, hormesis can be
observed if simultaneous binding of substrate and competitor enhances a response
of the homo-multimer. We characterized this mechanism of hormesis in binding
experiments that analyzed the interaction of homotrimeric proliferating cell
nuclear antigen (PCNA) with uracil DNA glycosylase (UNG2) and a
fluorescein-labeled peptide. Additionally, the basic features of this molecular
mechanism appear to be conserved with at least two enzymes that are stimulated
by low doses of inhibitor: dimeric BRAF and octameric glutamine synthetase 2
(GS2). Identifying such molecular mechanisms of hormesis may help explain
specific hormetic responses of cells and organisms treated with exogenous
compounds.
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Affiliation(s)
- Sharon N Greenwood
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, USA
| | - Regina G Belz
- University of Hohenheim, Hans-Ruthenberg Institute, Stuttgart, Germany
| | - Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, USA
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9
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Torgasheva NA, Diatlova EA, Grin IR, Endutkin AV, Mechetin GV, Vokhtantsev IP, Yudkina AV, Zharkov DO. Noncatalytic Domains in DNA Glycosylases. Int J Mol Sci 2022; 23:ijms23137286. [PMID: 35806289 PMCID: PMC9266487 DOI: 10.3390/ijms23137286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 02/04/2023] Open
Abstract
Many proteins consist of two or more structural domains: separate parts that have a defined structure and function. For example, in enzymes, the catalytic activity is often localized in a core fragment, while other domains or disordered parts of the same protein participate in a number of regulatory processes. This situation is often observed in many DNA glycosylases, the proteins that remove damaged nucleobases thus initiating base excision DNA repair. This review covers the present knowledge about the functions and evolution of such noncatalytic parts in DNA glycosylases, mostly concerned with the human enzymes but also considering some unique members of this group coming from plants and prokaryotes.
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Affiliation(s)
- Natalia A. Torgasheva
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Evgeniia A. Diatlova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
| | - Inga R. Grin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Grigory V. Mechetin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Ivan P. Vokhtantsev
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
| | - Anna V. Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
- Correspondence:
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10
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Hong JY, Cassel J, Yang J, Lin H, Weiser BP. High-Throughput Screening Identifies Ascorbyl Palmitate as a SIRT2 Deacetylase and Defatty-Acylase Inhibitor. ChemMedChem 2021; 16:3484-3494. [PMID: 34382754 DOI: 10.1002/cmdc.202100343] [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: 05/18/2021] [Revised: 07/14/2021] [Indexed: 11/10/2022]
Abstract
Small-molecule inhibitors of the human sirtuin SIRT2 are being developed because of their therapeutic potential in a variety of diseases. Here, we developed a high-throughput screen to identify novel SIRT2 inhibitors using a fluorescent SIRT2 probe, 1-aminoanthracene (AMA). AMA has high fluorescence when bound to SIRT2, and its fluorescence reduces >10-fold when it is displaced from SIRT2 by other ligands. We used this property of AMA to screen a library of known bioactive compounds for SIRT2 binding and discovered two known pharmaceutical compounds that bind SIRT2 with Kd values in the low μM range, ascorbyl palmitate and pictilisib. Both compounds inhibit the deacetylase and defatty-acylase activities of SIRT2. While pictilisib has selectivity for SIRT2, ascorbyl palmitate also inhibits the enzymatic activities of SIRT1 and SIRT6. Finally, we show that ascorbyl palmitate inhibits SIRT2 deacetylase and defatty-acylase activities in cells, and SIRT2 inhibition by ascorbyl palmitate contributes to the cytotoxicity of the compound. Our work discovered novel SIRT2 deacylase inhibitors and presents a screening approach that can be applied on a larger scale.
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Affiliation(s)
- Jun Young Hong
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Joel Cassel
- Molecular Screening & Protein Expression Facility, Wistar Institute, Philadelphia, PA, 19104, USA
| | - Jie Yang
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA
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11
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Kavli B, Iveland TS, Buchinger E, Hagen L, Liabakk NB, Aas PA, Obermann TS, Aachmann FL, Slupphaug G. RPA2 winged-helix domain facilitates UNG-mediated removal of uracil from ssDNA; implications for repair of mutagenic uracil at the replication fork. Nucleic Acids Res 2021; 49:3948-3966. [PMID: 33784377 PMCID: PMC8053108 DOI: 10.1093/nar/gkab195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 01/14/2023] Open
Abstract
Uracil occurs at replication forks via misincorporation of deoxyuridine monophosphate (dUMP) or via deamination of existing cytosines, which occurs 2-3 orders of magnitude faster in ssDNA than in dsDNA and is 100% miscoding. Tethering of UNG2 to proliferating cell nuclear antigen (PCNA) allows rapid post-replicative removal of misincorporated uracil, but potential 'pre-replicative' removal of deaminated cytosines in ssDNA has been questioned since this could mediate mutagenic translesion synthesis and induction of double-strand breaks. Here, we demonstrate that uracil-DNA glycosylase (UNG), but not SMUG1 efficiently excises uracil from replication protein A (RPA)-coated ssDNA and that this depends on functional interaction between the flexible winged-helix (WH) domain of RPA2 and the N-terminal RPA-binding helix in UNG. This functional interaction is promoted by mono-ubiquitination and diminished by cell-cycle regulated phosphorylations on UNG. Six other human proteins bind the RPA2-WH domain, all of which are involved in DNA repair and replication fork remodelling. Based on this and the recent discovery of the AP site crosslinking protein HMCES, we propose an integrated model in which templated repair of uracil and potentially other mutagenic base lesions in ssDNA at the replication fork, is orchestrated by RPA. The UNG:RPA2-WH interaction may also play a role in adaptive immunity by promoting efficient excision of AID-induced uracils in transcribed immunoglobulin loci.
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Affiliation(s)
- Bodil Kavli
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Tobias S Iveland
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Cancer Clinic, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Edith Buchinger
- NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7034 Trondheim, Norway
| | - Lars Hagen
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Proteomics and Modomics Experimental Core at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Nina B Liabakk
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Per A Aas
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Tobias S Obermann
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Finn L Aachmann
- NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7034 Trondheim, Norway
| | - Geir Slupphaug
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Proteomics and Modomics Experimental Core at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
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12
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Perkins JL, Zhao L. The N-terminal domain of uracil-DNA glycosylase: Roles for disordered regions. DNA Repair (Amst) 2021; 101:103077. [PMID: 33640758 DOI: 10.1016/j.dnarep.2021.103077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 02/14/2021] [Indexed: 01/10/2023]
Abstract
The presence of uracil in DNA calls for rapid removal facilitated by the uracil-DNA glycosylase superfamily of enzymes, which initiates the base excision repair (BER) pathway. In humans, uracil excision is accomplished primarily by the human uracil-DNA glycosylase (hUNG) enzymes. In addition to BER, hUNG enzymes play a key role in somatic hypermutation to generate antibody diversity. hUNG has several isoforms, with hUNG1 and hUNG2 being the two major isoforms. Both isoforms contain disordered N-terminal domains, which are responsible for a wide range of functions, with minimal direct impact on catalytic efficiency. Subcellular localization of hUNG enzymes is directed by differing N-terminal sequences, with hUNG1 dedicated to mitochondria and hUNG2 dedicated to the nucleus. An alternative isoform of hUNG1 has also been identified to localize to the nucleus in mouse and human cell models. Furthermore, hUNG2 has been observed at replication forks performing both pre- and post-replicative uracil excision to maintain genomic integrity. Replication protein A (RPA) and proliferating cell nuclear antigen (PCNA) are responsible for recruitment to replication forks via protein-protein interactions with the N-terminus of hUNG2. These interactions, along with protein degradation, are regulated by various post-translational modifications within the N-terminal tail, which are primarily cell-cycle dependent. Finally, translocation on DNA is also mediated by interactions between the N-terminus and DNA, which is enhanced under molecular crowding conditions by preventing diffusion events and compacting tail residues. This review summarizes recent research supporting the emerging roles of the N-terminal domain of hUNG.
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Affiliation(s)
- Jacob L Perkins
- Department of Chemistry and Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, CA 92521, United States
| | - Linlin Zhao
- Department of Chemistry and Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, CA 92521, United States.
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13
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Hans F, Senarisoy M, Bhaskar Naidu C, Timmins J. Focus on DNA Glycosylases-A Set of Tightly Regulated Enzymes with a High Potential as Anticancer Drug Targets. Int J Mol Sci 2020; 21:ijms21239226. [PMID: 33287345 PMCID: PMC7730500 DOI: 10.3390/ijms21239226] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 12/25/2022] Open
Abstract
Cancer is the second leading cause of death with tens of millions of people diagnosed with cancer every year around the world. Most radio- and chemotherapies aim to eliminate cancer cells, notably by causing severe damage to the DNA. However, efficient repair of such damage represents a common mechanism of resistance to initially effective cytotoxic agents. Thus, development of new generation anticancer drugs that target DNA repair pathways, and more particularly the base excision repair (BER) pathway that is responsible for removal of damaged bases, is of growing interest. The BER pathway is initiated by a set of enzymes known as DNA glycosylases. Unlike several downstream BER enzymes, DNA glycosylases have so far received little attention and the development of specific inhibitors of these enzymes has been lagging. Yet, dysregulation of DNA glycosylases is also known to play a central role in numerous cancers and at different stages of the disease, and thus inhibiting DNA glycosylases is now considered a valid strategy to eliminate cancer cells. This review provides a detailed overview of the activities of DNA glycosylases in normal and cancer cells, their modes of regulation, and their potential as anticancer drug targets.
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14
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Bi D, Yang J, Hong JY, Parikh P, Hinds N, Infanti J, Lin H, Weiser BP. Substrate-Dependent Modulation of SIRT2 by a Fluorescent Probe, 1-Aminoanthracene. Biochemistry 2020; 59:3869-3878. [PMID: 32941003 PMCID: PMC7880049 DOI: 10.1021/acs.biochem.0c00564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Sirtuin isoform 2 (SIRT2) is an enzyme that catalyzes the removal of acyl groups from lysine residues. SIRT2's catalytic domain has a hydrophobic tunnel where its substrate acyl groups bind. Here, we report that the fluorescent probe 1-aminoanthracene (AMA) binds within SIRT2's hydrophobic tunnel in a substrate-dependent manner. AMA's interaction with SIRT2 was characterized by its enhanced fluorescence upon protein binding (>10-fold). AMA interacted weakly with SIRT2 alone in solution (Kd = 37 μM). However, when SIRT2 was equilibrated with a decanoylated peptide substrate, AMA's affinity for SIRT2 was enhanced ∼10-fold (Kd = 4 μM). The peptide's decanoyl chain and AMA co-occupied SIRT2's hydrophobic tunnel when bound to the protein. In contrast, binding of AMA to SIRT2 was competitive with a myristoylated substrate whose longer acyl chain occluded the entire tunnel. AMA competitively inhibited SIRT2 demyristoylase activity with an IC50 of 21 μM, which was significantly more potent than its inhibition of other deacylase activities. Finally, binding and structural analysis suggests that the AMA binding site in SIRT2's hydrophobic tunnel was structurally stabilized when SIRT2 interacted with a decanoylated or 4-oxononanoylated substrate, but AMA's binding site was less stable when SIRT2 was bound to an acetylated substrate. Our use of AMA to explore changes in SIRT2's hydrophobic tunnel that are induced by interactions with specific acylated substrates has implications for developing ligands that modulate SIRT2's substrate specificity.
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Affiliation(s)
- David Bi
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, New Jersey 08084, United States
| | - Jie Yang
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, New Jersey 08084, United States
| | - Jun Young Hong
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Prashit Parikh
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, New Jersey 08084, United States
| | - Nicole Hinds
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, New Jersey 08084, United States
| | - Joseph Infanti
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, New Jersey 08084, United States
| | - Hening Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.,Howard Hughes Medical Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, New Jersey 08084, United States
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15
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Chu N, Viennet T, Bae H, Salguero A, Boeszoermenyi A, Arthanari H, Cole PA. The structural determinants of PH domain-mediated regulation of Akt revealed by segmental labeling. eLife 2020; 9:e59151. [PMID: 32744507 PMCID: PMC7438110 DOI: 10.7554/elife.59151] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/03/2020] [Indexed: 12/19/2022] Open
Abstract
Akt is a critical protein kinase that governs cancer cell growth and metabolism. Akt appears to be autoinhibited by an intramolecular interaction between its N-terminal pleckstrin homology (PH) domain and kinase domain, which is relieved by C-tail phosphorylation, but the precise molecular mechanisms remain elusive. Here, we use a combination of protein semisynthesis, NMR, and enzymological analysis to characterize structural features of the PH domain in its autoinhibited and activated states. We find that Akt autoinhibition depends on the length/flexibility of the PH-kinase linker. We identify a role for a dynamic short segment in the PH domain that appears to regulate autoinhibition and PDK1-catalyzed phosphorylation of Thr308 in the activation loop. We determine that Akt allosteric inhibitor MK2206 drives distinct PH domain structural changes compared to baseline autoinhibited Akt. These results highlight how the conformational plasticity of Akt governs the delicate control of its catalytic properties.
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Affiliation(s)
- Nam Chu
- Division of Genetics, Department of Medicine, Brigham and Women's HospitalBostonUnited States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Thibault Viennet
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
- Department of Cancer Biology, Dana-Farber Cancer InstituteBostonUnited States
| | - Hwan Bae
- Division of Genetics, Department of Medicine, Brigham and Women's HospitalBostonUnited States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
| | - Antonieta Salguero
- Division of Genetics, Department of Medicine, Brigham and Women's HospitalBostonUnited States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Andras Boeszoermenyi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
- Department of Cancer Biology, Dana-Farber Cancer InstituteBostonUnited States
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
- Department of Cancer Biology, Dana-Farber Cancer InstituteBostonUnited States
| | - Philip A Cole
- Division of Genetics, Department of Medicine, Brigham and Women's HospitalBostonUnited States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of MedicineBaltimoreUnited States
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16
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Abstract
Protein semisynthesis-defined herein as the assembly of a protein from a combination of synthetic and recombinant fragments-is a burgeoning field of chemical biology that has impacted many areas in the life sciences. In this review, we provide a comprehensive survey of this area. We begin by discussing the various chemical and enzymatic methods now available for the manufacture of custom proteins containing noncoded elements. This section begins with a discussion of methods that are more chemical in origin and ends with those that employ biocatalysts. We also illustrate the commonalities that exist between these seemingly disparate methods and show how this is allowing for the development of integrated chemoenzymatic methods. This methodology discussion provides the technical foundation for the second part of the review where we cover the great many biological problems that have now been addressed using these tools. Finally, we end the piece with a short discussion on the frontiers of the field and the opportunities available for the future.
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Affiliation(s)
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, United States
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17
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Weiser BP. Analysis of uracil DNA glycosylase (UNG2) stimulation by replication protein A (RPA) at ssDNA-dsDNA junctions. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1868:140347. [PMID: 31866506 DOI: 10.1016/j.bbapap.2019.140347] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/12/2019] [Accepted: 12/17/2019] [Indexed: 12/17/2022]
Abstract
Replication Protein A (RPA) is a single-stranded DNA binding protein that interacts with DNA repair proteins including Uracil DNA Glycosylase (UNG2). Here, I report DNA binding and activity assays using purified recombinant RPA and UNG2. Using synthetic DNA substrates, RPA was found to promote UNG2's interaction with ssDNA-dsDNA junctions regardless of the DNA strand polarity surrounding the junction. RPA stimulated UNG2's removal of uracil bases paired with adenine or guanine in DNA as much as 17-fold when the uracil was positioned 21 bps from ssDNA-dsDNA junctions, and the largest degree of UNG2 stimulation occurred when RPA was in molar excess compared to DNA. I found that RPA becomes sequestered on ssDNA regions surrounding junctions which promotes its spatial targeting of UNG2 near the junction. However, when RPA concentration exceeds free ssDNA, RPA promotes UNG2's activity without spatial constraints in dsDNA regions. These effects of RPA on UNG2 were found to be mediated primarily by interactions between RPA's winged-helix domain and UNG2's N-terminal domain, but when the winged-helix domain is unavailable, a secondary interaction between UNG2's N-terminal domain and RPA can occur. This work supports a widespread role for RPA in stimulating uracil base excision repair.
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Affiliation(s)
- Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA.
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18
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Rodriguez G, Orris B, Majumdar A, Bhat S, Stivers JT. Macromolecular crowding induces compaction and DNA binding in the disordered N-terminal domain of hUNG2. DNA Repair (Amst) 2019; 86:102764. [PMID: 31855846 DOI: 10.1016/j.dnarep.2019.102764] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/25/2019] [Accepted: 12/04/2019] [Indexed: 11/15/2022]
Abstract
Many human DNA repair proteins have disordered domains at their N- or C-termini with poorly defined biological functions. We recently reported that the partially structured N-terminal domain (NTD) of human uracil DNA glycosylase 2 (hUNG2), functions to enhance DNA translocation in crowded environments and also targets the enzyme to single-stranded/double-stranded DNA junctions. To understand the structural basis for these effects we now report high-resolution heteronuclear NMR studies of the isolated NTD in the presence and absence of an inert macromolecular crowding agent (PEG8K). Compared to dilute buffer, we find that crowding reduces the degrees of freedom for the structural ensemble, increases the order of a PCNA binding motif and dramatically promotes binding of the NTD for DNA through a conformational selection mechanism. These findings shed new light on the function of this disordered domain in the context of the crowded nuclear environment.
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Affiliation(s)
- Gaddiel Rodriguez
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, United States
| | - Benjamin Orris
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, United States
| | - Ananya Majumdar
- Biomolecular NMR Center, Johns Hopkins University, Baltimore, MD 21218, United States
| | - Shridhar Bhat
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, United States
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, United States.
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19
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Sarno A, Lundbæk M, Liabakk NB, Aas PA, Mjelle R, Hagen L, Sousa MML, Krokan HE, Kavli B. Uracil-DNA glycosylase UNG1 isoform variant supports class switch recombination and repairs nuclear genomic uracil. Nucleic Acids Res 2019; 47:4569-4585. [PMID: 30838409 PMCID: PMC6511853 DOI: 10.1093/nar/gkz145] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 01/18/2019] [Accepted: 02/25/2019] [Indexed: 11/23/2022] Open
Abstract
UNG is the major uracil-DNA glycosylase in mammalian cells and is involved in both error-free base excision repair of genomic uracil and mutagenic uracil-processing at the antibody genes. However, the regulation of UNG in these different processes is currently not well understood. The UNG gene encodes two isoforms, UNG1 and UNG2, each possessing unique N-termini that mediate translocation to the mitochondria and the nucleus, respectively. A strict subcellular localization of each isoform has been widely accepted despite a lack of models to study them individually. To determine the roles of each isoform, we generated and characterized several UNG isoform-specific mouse and human cell lines. We identified a distinct UNG1 isoform variant that is targeted to the cell nucleus where it supports antibody class switching and repairs genomic uracil. We propose that the nuclear UNG1 variant, which in contrast to UNG2 lacks a PCNA-binding motif, may be specialized to act on ssDNA through its ability to bind RPA. RPA-coated ssDNA regions include both transcribed antibody genes that are targets for deamination by AID and regions in front of the moving replication forks. Our findings provide new insights into the function of UNG isoforms in adaptive immunity and DNA repair.
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Affiliation(s)
- Antonio Sarno
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Core Facility for Proteomics and Modomics at NTNU and the Central Norway Regional Health Authority
| | - Marie Lundbæk
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Nina Beate Liabakk
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Per Arne Aas
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Robin Mjelle
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Lars Hagen
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,PROMEC Core Facility for Proteomics and Modomics at NTNU and the Central Norway Regional Health Authority
| | - Mirta M L Sousa
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Core Facility for Proteomics and Modomics at NTNU and the Central Norway Regional Health Authority
| | - Hans E Krokan
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Bodil Kavli
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
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20
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Jiang H, Thomas SN, Chen Z, Chiang CY, Cole PA. Comparative analysis of the catalytic regulation of NEDD4-1 and WWP2 ubiquitin ligases. J Biol Chem 2019; 294:17421-17436. [PMID: 31578285 DOI: 10.1074/jbc.ra119.009211] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 09/23/2019] [Indexed: 12/25/2022] Open
Abstract
NEDD4-1 E3 ubiquitin protein ligase (NEDD4-1) and WW domain-containing E3 ubiquitin ligase (WWP2) are HECT family ubiquitin E3 ligases. They catalyze Lys ubiquitination of themselves and other proteins and are important in cell growth and differentiation. Regulation of NEDD4-1 and WWP2 catalytic activities is important for controlling cellular protein homeostasis, and their dysregulation may lead to cancer and other diseases. Previous work has implicated noncatalytic regions, including the C2 domain and/or WW domain linkers in NEDD4-1 and WWP2, in contributing to autoinhibition of the catalytic HECT domains by intramolecular interactions. Here, we explored the molecular mechanisms of these NEDD4-1 and WWP2 regulatory regions and their interplay with allosteric binding proteins such as Nedd4 family-interacting protein (NDFIP1), engineered ubiquitin variants, and linker phosphomimics. We found that in addition to influencing catalytic activities, the WW domain linker regions in NEDD4-1 and WWP2 can impact product distribution, including the degree of polyubiquitination and Lys-48 versus Lys-63 linkages. We show that allosteric activation by NDFIP1 or engineered ubiquitin variants is largely mediated by relief of WW domain linker autoinhibition. WWP2-mediated ubiquitination of WW domain-binding protein 2 (WBP2), phosphatase and tensin homolog (PTEN), and p62 proteins by WWP2 suggests that substrate ubiquitination can also be influenced by WW linker autoinhibition, although to differing extents. Overall, our results provide a deeper understanding of the intricate and multifaceted set of regulatory mechanisms in the control of NEDD4-1-related ubiquitin ligases.
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Affiliation(s)
- Hanjie Jiang
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115.,Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205
| | - Stefani N Thomas
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287
| | - Zan Chen
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205
| | - Claire Y Chiang
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218
| | - Philip A Cole
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115 .,Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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21
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Weiser BP, Rodriguez G, Cole PA, Stivers JT. N-terminal domain of human uracil DNA glycosylase (hUNG2) promotes targeting to uracil sites adjacent to ssDNA-dsDNA junctions. Nucleic Acids Res 2019; 46:7169-7178. [PMID: 29917162 PMCID: PMC6101581 DOI: 10.1093/nar/gky525] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 05/24/2018] [Indexed: 01/29/2023] Open
Abstract
The N-terminal domain (NTD) of nuclear human uracil DNA glycosylase (hUNG2) assists in targeting hUNG2 to replication forks through specific interactions with replication protein A (RPA). Here, we explored hUNG2 activity in the presence and absence of RPA using substrates with ssDNA–dsDNA junctions that mimic structural features of the replication fork and transcriptional R-loops. We find that when RPA is tightly bound to the ssDNA overhang of junction DNA substrates, base excision by hUNG2 is strongly biased toward uracils located 21 bp or less from the ssDNA–dsDNA junction. In the absence of RPA, hUNG2 still showed an 8-fold excision bias for uracil located <10 bp from the junction, but only when the overhang had a 5′ end. Biased targeting required the NTD and was not observed with the hUNG2 catalytic domain alone. Consistent with this requirement, the isolated NTD was found to bind weakly to ssDNA. These findings indicate that the NTD of hUNG2 targets the enzyme to ssDNA–dsDNA junctions using RPA-dependent and RPA-independent mechanisms. This structure-based specificity may promote efficient removal of uracils that arise from dUTP incorporation during DNA replication, or additionally, uracils that arise from DNA cytidine deamination at transcriptional R-loops during immunoglobulin class-switch recombination.
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Affiliation(s)
- Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Gaddiel Rodriguez
- Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Philip A Cole
- Division of Genetics, Department of Medicine and Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - James T Stivers
- Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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22
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Esadze A, Stivers JT. Facilitated Diffusion Mechanisms in DNA Base Excision Repair and Transcriptional Activation. Chem Rev 2018; 118:11298-11323. [PMID: 30379068 DOI: 10.1021/acs.chemrev.8b00513] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Preservation of the coding potential of the genome and highly regulated gene expression over the life span of a human are two fundamental requirements of life. These processes require the action of repair enzymes or transcription factors that efficiently recognize specific sites of DNA damage or transcriptional regulation within a restricted time frame of the cell cycle or metabolism. A failure of these systems to act results in accumulated mutations, metabolic dysfunction, and disease. Despite the multifactorial complexity of cellular DNA repair and transcriptional regulation, both processes share a fundamental physical requirement that the proteins must rapidly diffuse to their specific DNA-binding sites that are embedded within the context of a vastly greater number of nonspecific DNA-binding sites. Superimposed on the needle-in-the-haystack problem is the complex nature of the cellular environment, which contains such high concentrations of macromolecules that the time frame for diffusion is expected to be severely extended as compared to dilute solution. Here we critically review the mechanisms for how these proteins solve the needle-in-the-haystack problem and how the effects of cellular macromolecular crowding can enhance facilitated diffusion processes. We restrict the review to human proteins that use stochastic, thermally driven site-recognition mechanisms, and we specifically exclude systems involving energy cofactors or circular DNA clamps. Our scope includes ensemble and single-molecule studies of the past decade or so, with an emphasis on connecting experimental observations to biological function.
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Affiliation(s)
- Alexandre Esadze
- Department of Pharmacology and Molecular Sciences , Johns Hopkins University School of Medicine , 725 North Wolfe Street , WBSB 314, Baltimore , Maryland 21205 , United States
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences , Johns Hopkins University School of Medicine , 725 North Wolfe Street , WBSB 314, Baltimore , Maryland 21205 , United States
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23
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Chu N, Salguero AL, Liu AZ, Chen Z, Dempsey DR, Ficarro SB, Alexander WM, Marto JA, Li Y, Amzel LM, Gabelli SB, Cole PA. Akt Kinase Activation Mechanisms Revealed Using Protein Semisynthesis. Cell 2018; 174:897-907.e14. [PMID: 30078705 DOI: 10.1016/j.cell.2018.07.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/15/2018] [Accepted: 07/03/2018] [Indexed: 11/30/2022]
Abstract
Akt is a critical protein kinase that drives cancer proliferation, modulates metabolism, and is activated by C-terminal phosphorylation. The current structural model for Akt activation by C-terminal phosphorylation has centered on intramolecular interactions between the C-terminal tail and the N lobe of the kinase domain. Here, we employ expressed protein ligation to produce site-specifically phosphorylated forms of purified Akt1 that are well suited for mechanistic analysis. Using biochemical, crystallographic, and cellular approaches, we determine that pSer473-Akt activation is driven by an intramolecular interaction between the C-tail and the pleckstrin homology (PH)-kinase domain linker that relieves PH domain-mediated Akt1 autoinhibition. Moreover, dual phosphorylation at Ser477/Thr479 activates Akt1 through a different allosteric mechanism via an apparent activation loop interaction that reduces autoinhibition by the PH domain and weakens PIP3 affinity. These results provide a new framework for understanding how Akt is controlled in cell signaling and suggest distinct functions for differentially modified Akt forms.
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Affiliation(s)
- Nam Chu
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Antonieta L Salguero
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Albert Z Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Zan Chen
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Daniel R Dempsey
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Scott B Ficarro
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - William M Alexander
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Jarrod A Marto
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yana Li
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - L Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Sandra B Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Philip A Cole
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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24
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Dempsey DR, Jiang H, Kalin JH, Chen Z, Cole PA. Site-Specific Protein Labeling with N-Hydroxysuccinimide-Esters and the Analysis of Ubiquitin Ligase Mechanisms. J Am Chem Soc 2018; 140:9374-9378. [PMID: 30016585 DOI: 10.1021/jacs.8b05098] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
N-Hydroxysuccinimide (NHS)-esters are widely used to label proteins nonselectively on free amino groups. Such broad labeling can be disadvantageous because it can interfere with protein structure or function and because stoichiometry is poorly controlled. Here we describe a simple method to transform NHS-esters into site-specific protein labeling on N-terminal Cys residues. MESNA addition converts NHS-esters to chemoselective thioesters for N-Cys modification. This labeling strategy was applied to clarify mechanistic features of the ubiquitin E3 ligase WWP2 including its interaction with one of its substrates, the tumor suppressor PTEN, as well as its autoubiquitination molecularity. We propose that this convenient protein labeling strategy will allow for an expanded application of NHS-esters in biochemical investigation.
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Affiliation(s)
- Daniel R Dempsey
- Division of Genetics, Departments of Medicine and Biological Chemistry and Molecular Pharmacology , Harvard Medical School and Brigham and Women's Hospital , Boston , Massachusetts 02115 , United States
| | - Hanjie Jiang
- Department of Pharmacology and Molecular Sciences , Johns Hopkins School of Medicine , Baltimore , Maryland 21205 , United States
| | - Jay H Kalin
- Division of Genetics, Departments of Medicine and Biological Chemistry and Molecular Pharmacology , Harvard Medical School and Brigham and Women's Hospital , Boston , Massachusetts 02115 , United States
| | - Zan Chen
- Department of Pharmacology and Molecular Sciences , Johns Hopkins School of Medicine , Baltimore , Maryland 21205 , United States
| | - Philip A Cole
- Division of Genetics, Departments of Medicine and Biological Chemistry and Molecular Pharmacology , Harvard Medical School and Brigham and Women's Hospital , Boston , Massachusetts 02115 , United States.,Department of Pharmacology and Molecular Sciences , Johns Hopkins School of Medicine , Baltimore , Maryland 21205 , United States
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25
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Moor NA, Lavrik OI. Protein–Protein Interactions in DNA Base Excision Repair. BIOCHEMISTRY (MOSCOW) 2018; 83:411-422. [DOI: 10.1134/s0006297918040120] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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26
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Esadze A, Rodriguez G, Weiser BP, Cole PA, Stivers JT. Measurement of nanoscale DNA translocation by uracil DNA glycosylase in human cells. Nucleic Acids Res 2017; 45:12413-12424. [PMID: 29036472 PMCID: PMC5716149 DOI: 10.1093/nar/gkx848] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/13/2017] [Indexed: 12/17/2022] Open
Abstract
DNA ‘sliding’ by human repair enzymes is considered to be important for DNA damage detection. Here, we transfected uracil-containing DNA duplexes into human cells and measured the probability that nuclear human uracil DNA glycosylase (hUNG2) excised two uracil lesions spaced 10–80 bp apart in a single encounter without escaping the micro-volume containing the target sites. The two-site transfer probabilities were 100% and 54% at a 10 and 40 bp spacing, but dropped to only 10% at 80 bp. Enzyme trapping experiments suggested that site transfers over 40 bp followed a DNA ‘hopping’ pathway in human cells, indicating that authentic sliding does not occur even over this short distance. The transfer probabilities were much greater than observed in aqueous buffers, but similar to in vitro measurements in the presence of polymer crowding agents. The findings reveal a new role for the crowded nuclear environment in facilitating DNA damage detection.
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Affiliation(s)
- Alexandre Esadze
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
| | - Gaddiel Rodriguez
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
| | - Brian P Weiser
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
| | - Philip A Cole
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
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27
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Rodriguez G, Esadze A, Weiser BP, Schonhoft JD, Cole PA, Stivers JT. Disordered N-Terminal Domain of Human Uracil DNA Glycosylase (hUNG2) Enhances DNA Translocation. ACS Chem Biol 2017; 12:2260-2263. [PMID: 28787572 DOI: 10.1021/acschembio.7b00521] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nuclear human uracil-DNA glycosylase (hUNG2) initiates base excision repair (BER) of genomic uracils generated through misincorporation of dUMP or through deamination of cytosines. Like many human DNA glycosylases, hUNG2 contains an unstructured N-terminal domain that encodes a nuclear localization signal, protein binding motifs, and sites for post-translational modifications. Although the N-terminal domain has minimal effects on DNA binding and uracil excision kinetics, we report that this domain enhances the ability of hUNG2 to translocate on DNA chains as compared to the catalytic domain alone. The enhancement is most pronounced when physiological ion concentrations and macromolecular crowding agents are used. These data suggest that crowded conditions in the human cell nucleus promote the interaction of the N-terminus with duplex DNA during translocation. The increased contact time with the DNA chain likely contributes to the ability of hUNG2 to locate densely spaced uracils that arise during somatic hypermutation and during fluoropyrimidine chemotherapy.
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Affiliation(s)
- Gaddiel Rodriguez
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205−2185, United States
| | - Alexandre Esadze
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205−2185, United States
| | - Brian P. Weiser
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205−2185, United States
| | - Joseph D. Schonhoft
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205−2185, United States
| | - Philip A. Cole
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205−2185, United States
| | - James T. Stivers
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205−2185, United States
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