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Yu B, Kruse N, Howard KM, Kingsley K. Downstream Target Analysis for miR-365 among Oral Squamous Cell Carcinomas Reveals Differential Associations with Chemoresistance. Life (Basel) 2024; 14:741. [PMID: 38929724 PMCID: PMC11205150 DOI: 10.3390/life14060741] [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: 03/28/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024] Open
Abstract
Expression of microRNAs, such as miR-365, is known to be dysregulated in many tumors, including oral cancers, although little is known about their role or functions. The objective of this project is to evaluate the downstream targets of miR-365 to determine any potential pathways or effects. Downstream targets for miR-365 (miRdatabase target scores > 90) were used for qPCR screening of oral cancer cell lines (SCC4, SCC9, SCC15, SCC25, CAL27). Each oral cancer cell line expressed miR-365 downstream targets molybdenum cofactor synthesis-2 (MOCS2), erythropoietin receptor (EPOR), IQ motif containing-K (IQCK), carboxypeptidase A3 (CPA3), solute carrier family 24 member-3 (SLC24A3), and coiled-coil domain containing 47 (CCDC47)-although the expression levels varied somewhat. However, differential results were observed with ubiquitin protein ligase E3 component n-recognin-3 (UBR3), nudix hydrolase-12 (NUDT12), zinc finger CCHC-type containing-14 (ZCCHC14), and homeobox and leucine zipper encoding (HOMEZ). These data suggest that many of the miR-365 targets are expressed in the oral cancers screened, with the differential expression of UBR3, ZCCHC14, HOMEZ, and NUDT12, which may be correlated with chemoresistance among two specific oral cancer cell lines (SCC25, SCC9). These results suggest this differential expression may signal potential targets for patient treatment with tumors exhibiting miR-365 and chemotherapeutic resistance.
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Affiliation(s)
- Brendon Yu
- Department of Clinical Sciences, School of Dental Medicine, University of Nevada-Las Vegas, 1700 W. Charleston Boulevard, Las Vegas, NV 89106, USA
| | - Nathaniel Kruse
- Department of Clinical Sciences, School of Dental Medicine, University of Nevada-Las Vegas, 1700 W. Charleston Boulevard, Las Vegas, NV 89106, USA
| | - Katherine M. Howard
- Department of Biomedical Sciences, School of Dental Medicine, University of Nevada-Las Vegas, 1001 Shadow Lane, Las Vegas, NV 89106, USA;
| | - Karl Kingsley
- Department of Biomedical Sciences, School of Dental Medicine, University of Nevada-Las Vegas, 1001 Shadow Lane, Las Vegas, NV 89106, USA;
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2
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McMahon A, Zhao J, Yan S. Ubiquitin-mediated regulation of APE2 protein abundance. J Biol Chem 2024; 300:107337. [PMID: 38705397 PMCID: PMC11157268 DOI: 10.1016/j.jbc.2024.107337] [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: 10/30/2023] [Revised: 04/12/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
APE2 plays important roles in the maintenance of genomic and epigenomic stability including DNA repair and DNA damage response. Accumulating evidence has suggested that APE2 is upregulated in multiple cancers at the protein and mRNA levels and that APE2 upregulation is correlative with higher and lower overall survival of cancer patients depending on tumor type. However, it remains unknown how APE2 protein abundance is maintained and regulated in cells. Here, we provide the first evidence of APE2 regulation via the posttranslational modification ubiquitin. APE2 is poly-ubiquitinated via K48-linked chains and degraded via the ubiquitin-proteasome system where K371 is the key residue within APE2 responsible for its ubiquitination and degradation. We further characterize MKRN3 as the E3 ubiquitin ligase for APE2 ubiquitination in cells and in vitro. In summary, this study offers the first definition of the APE2 proteostasis network and lays the foundation for future studies pertaining to the posttranslational modification regulation and functions of APE2 in genome integrity and cancer etiology/treatment.
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Affiliation(s)
- Anne McMahon
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA; School of Data Science, University of North Carolina at Charlotte, Charlotte, North Carolina, USA; Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina, USA.
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3
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Cao X, Zheng J, Zhang R, Sun Y, Zhao M. Live-cell imaging of human apurinic/apyrimidinic endonuclease 1 in the nucleus and nucleolus using a chaperone@DNA probe. Nucleic Acids Res 2024; 52:e41. [PMID: 38554110 PMCID: PMC11077052 DOI: 10.1093/nar/gkae202] [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: 06/17/2023] [Accepted: 03/07/2024] [Indexed: 04/01/2024] Open
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) plays crucial roles in repairing DNA damage and regulating RNA in the nucleus. However, direct visualization of nuclear APE1 in live cells remains challenging. Here, we report a chaperone@DNA probe for live-cell imaging of APE1 in the nucleus and nucleolus in real time. The probe is based on an assembly of phenylboronic acid modified avidin and biotin-labeled DNA containing an abasic site (named PB-ACP), which cleverly protects DNA from being nonspecifically destroyed while enabling targeted delivery of the probe to the nucleus. The PB-ACP construct specifically detects APE1 due to the high binding affinity of APE1 for both avidin and the abasic site in DNA. It is easy to prepare, biocompatible and allowing for long-term observation of APE1 activity. This molecular tool offers a powerful means to investigate the behavior of APE1 in the nuclei of various types of live cells, particularly for the development of improved cancer therapies targeting this protein.
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Affiliation(s)
- Xiangjian Cao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jinghui Zheng
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ruilan Zhang
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ying Sun
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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4
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Li L, Sheng Q, Zeng H, Li W, Wang Q, Ma G, Xu X, Qiu M, Zhang W, Shan C. Specific genetic aberrations of parathyroid in Chinese patients with tertiary hyperparathyroidism using whole-exome sequencing. Front Endocrinol (Lausanne) 2023; 14:1221060. [PMID: 37854190 PMCID: PMC10579901 DOI: 10.3389/fendo.2023.1221060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 09/07/2023] [Indexed: 10/20/2023] Open
Abstract
Background Tertiary hyperparathyroidism (THPT) is a peculiar subtype of hyperparathyroidism that usually develops from chronic kidney disease (CKD) and persists even after kidney transplantation. Unlike its precursor, secondary hyperparathyroidism (SHPT), THPT is characterized by uncontrolled high levels of calcium in the blood, which suggests the monoclonal or oligoclonal proliferation of parathyroid cells. However, the molecular abnormalities leading to THPT have not yet been fully understood. Methods In this study, we analyzed DNA samples from hyperplastic parathyroid and corresponding blood cells of 11 patients with THPT using whole-exome sequencing (WES). We identified somatic single nucleotide variants (SNV) and insertions or deletions variants (INDEL) and performed driver mutation analysis, KEGG pathway, and GO functional enrichment analysis. To confirm the impact of selected driver mutated genes, we also tested their expression level in these samples using qRT-PCR. Results Following quality control and mutation filtering, we identified 17,401 mutations, comprising 6690 missense variants, 3078 frameshift variants, 2005 stop-gained variants, and 1630 synonymous variants. Copy number variants (CNV) analysis showed that chromosome 22 copy number deletion was frequently observed in 6 samples. Driver mutation analysis identified 179 statistically significant mutated genes, including recurrent missense mutations on TBX20, ATAD5, ZNF669, and NOX3 genes in 3 different patients. KEGG pathway analysis revealed two enriched pathways: non-homologous end-joining and cell cycle, with a sole gene, PRKDC, involved. GO analysis demonstrated significant enrichment of various cellular components and cytobiological processes associated with four genes, including GO items of positive regulation of developmental growth, protein ubiquitination, and positive regulation of the apoptotic process. Compared to blood samples, THPT samples exhibited lower expression levels of PRKDC, TBX20, ATAD5, and NOX3 genes. THPT samples with exon mutations had relatively lower expression levels of PRKDC, TBX20, and NOX3 genes compared to those without mutations, although the difference was not statistically significant. Conclusion This study provides a comprehensive landscape of the genetic characteristics of hyperplastic parathyroids in THPT, highlighting the involvement of multiple genes and pathways in the development and progression of this disease. The dominant mutations identified in our study depicted new insights into the pathogenesis and molecular characteristics of THPT.
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Affiliation(s)
- Lei Li
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qixuan Sheng
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Huajin Zeng
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Wei Li
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Qiang Wang
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Guanjun Ma
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Xinyun Xu
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Ming Qiu
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Wei Zhang
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
| | - Chengxiang Shan
- Department of Thyroid, Breast and Hernia Surgery of Changzheng Hospital Affiliated with Naval Military Medical University, Shanghai, China
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Tabanifar B, Moorthy A, Tsai HH, Kannan S, Verma CS, Sabapathy K. JNK mediates cell death by promoting the ubiquitination of the apurinic/apyrimidinic endonuclease APE1. Cell Rep 2023; 42:113123. [PMID: 37703179 DOI: 10.1016/j.celrep.2023.113123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/19/2023] [Accepted: 08/28/2023] [Indexed: 09/15/2023] Open
Abstract
The c-Jun-NH2-terminal kinases (JNKs) regulate cell death, generally through the direct phosphorylation of both pro- and anti-apoptotic substrates. In this report, we demonstrate an alternate mechanism of JNK-mediated cell death involving the anti-apoptotic protein human apurinic/apyrimidinic endonuclease 1 (APE1). Treatment of cells with a variety of genotoxic stresses enhanced APE1-JNK (all isoforms of JNK1 or JNK2) interaction, specifically in cells undergoing apoptosis. Steady-state APE1 levels were decreased in these cells, in which APE1 is ubiquitinated and degraded in a JNK-dependent manner. Absence of JNKs reduced APE1 ubiquitination and increased its abundance. Mechanistically, the E3 ligase ITCH associates with both APE1 and JNK and is necessary for JNK-dependent APE1 ubiquitination and degradation. Structural models of the JNK-APE1 interaction support the observation of enhanced association of the complex in the presence of ubiquitin. The data together show a mechanism of JNK-mediated cell death by the degradation of APE1 through ITCH.
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Affiliation(s)
- Bahareh Tabanifar
- Divisions of Cellular & Molecular Research, National Cancer Centre Singapore, Singapore 168583, Singapore
| | - Anbalagan Moorthy
- Divisions of Cellular & Molecular Research, National Cancer Centre Singapore, Singapore 168583, Singapore
| | - Heng Hang Tsai
- Queensland Health Forensic and Scientific Services, Coopers Plains, QLD 4108, Australia
| | | | - Chandra S Verma
- Bioinformatics Institute, ASTAR, Singapore 138671, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Kanaga Sabapathy
- Divisions of Cellular & Molecular Research, National Cancer Centre Singapore, Singapore 168583, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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6
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Siswanto FM, Okukawa K, Tamura A, Oguro A, Imaoka S. Hydrogen peroxide activates APE1/Ref-1 via NF-κB and Parkin: A role in liver cancer resistance to oxidative stress. Free Radic Res 2023:1-31. [PMID: 37364176 DOI: 10.1080/10715762.2023.2229509] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/09/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
Cancer cells exhibit an altered redox balance and aberrant redox signaling due to genetic, metabolic, and microenvironment-associated reprogramming. Persistently elevated levels of reactive oxygen species (ROS) contribute to many aspects of tumor development and progression. Emerging studies demonstrated the vital role of apurinic/apyrimidinic endonuclease 1 or reduction/oxidation (redox) factor 1(APE1/Ref-1) in the oxidative stress response and survival of cancer cells. APE1/Ref-1 is a multifunctional enzyme involved in the DNA damage response and functions as a redox regulator of transcription factors. We herein demonstrated that basal hydrogen peroxide (H2O2) and APE1/Ref-1 expression levels were markedly higher in cancer cell lines than in non-cancerous cells. Elevated APE1/Ref-1 levels were associated with shorter survival in liver cancer patients. Mechanistically, we showed that H2O2 activated nuclear factor-κB (NF-κB). RelA/p65 inhibited the expression of the E3 ubiquitin ligase Parkin, possibly by interfering with ATF4 activity. Parkin was responsible for the ubiquitination and proteasomal degradation of APE1/Ref-1; therefore, the H2O2-induced suppression of Parkin expression increased APE1/Ref-1 levels. The probability of survival was lower in liver cancer patients with low Parkin and high RelA expression levels. Additionally, Parkin and RelA expression levels negatively and positively correlated with APE1/Ref-1 levels, respectively, in the TCGA liver cancer cohort. We concluded that increases in APE1/Ref-1 via the NF-κB and Parkin pathways are critical for cancer cell survival under oxidative stress. The present results show the potential of the NF-κB-Parkin-APE1/Ref-1 axis as a prognostic factor and therapeutic strategy to eradicate liver cancer.
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Affiliation(s)
- Ferbian Milas Siswanto
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
- Department of Biochemistry, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Jakarta, Indonesia
| | - Kenta Okukawa
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
| | - Akiyoshi Tamura
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
| | - Ami Oguro
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Susumu Imaoka
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
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7
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Coskun E, Singh N, Scanlan LD, Jaruga P, Doak SH, Dizdaroglu M, Nelson BC. Inhibition of human APE1 and MTH1 DNA repair proteins by dextran-coated γ-Fe 2O 3 ultrasmall superparamagnetic iron oxide nanoparticles. Nanomedicine (Lond) 2022; 17:2011-2021. [PMID: 36853189 PMCID: PMC10031551 DOI: 10.2217/nnm-2022-0204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Aim: To quantitatively evaluate the inhibition of human DNA repair proteins APE1 and MTH1 by dextran-coated γ-Fe2O3 ultrasmall superparamagnetic iron oxide nanoparticles (dUSPIONs). Materials & methods: Liquid chromatography-tandem mass spectrometry with isotope-dilution was used to measure the expression levels of APE1 and MTH1 in MCL-5 cells exposed to increasing doses of dUSPIONs. The expression levels of APE1 and MTH1 were measured in cytoplasmic and nuclear fractions of cell extracts. Results: APE1 and MTH1 expression was significantly inhibited in both cell fractions at the highest dUSPION dose. The expression of MTH1 was linearly inhibited across the full dUSPION dose range in both fractions. Conclusion: These findings warrant further studies to characterize the capacity of dUSPIONs to inhibit other DNA repair proteins in vitro and in vivo.
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Affiliation(s)
- Erdem Coskun
- Institute for Bioscience & Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Neenu Singh
- Leicester School of Allied Health Sciences, Faculty of Health & Life Sciences, De Montfort University, The Gateway, Leicester, LE1 9BH, UK
| | - Leona D Scanlan
- California Environmental Protection Agency, Office of Environmental Health Hazard Assessment, 1001 I Street, Sacramento, CA 95814, USA
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards & Technology, Gaithersburg, MD 20899, USA
| | - Shareen H Doak
- Institute of Life Science, Center for NanoHealth, Swansea University Medical School, Wales, SA2 8PP, UK
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards & Technology, Gaithersburg, MD 20899, USA
| | - Bryant C Nelson
- Biosystems & Biomaterials Division, National Institute of Standards & Technology, Gaithersburg, MD 20899, USA
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8
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Rampoldi A, Forghani P, Li D, Hwang H, Armand LC, Fite J, Boland G, Maxwell J, Maher K, Xu C. Space microgravity improves proliferation of human iPSC-derived cardiomyocytes. Stem Cell Reports 2022; 17:2272-2285. [PMID: 36084640 PMCID: PMC9561632 DOI: 10.1016/j.stemcr.2022.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022] Open
Abstract
In microgravity, cells undergo profound changes in their properties. However, how human cardiac progenitors respond to space microgravity is unknown. In this study, we evaluated the effect of space microgravity on differentiation of human induced pluripotent stem cell (hiPSC)-derived cardiac progenitors compared with 1G cultures on the International Space Station (ISS). Cryopreserved 3D cardiac progenitors were cultured for 3 weeks on the ISS. Compared with 1G cultures, the microgravity cultures had 3-fold larger sphere sizes, 20-fold higher counts of nuclei, and increased expression of proliferation markers. Highly enriched cardiomyocytes generated in space microgravity showed improved Ca2+ handling and increased expression of contraction-associated genes. Short-term exposure (3 days) of cardiac progenitors to space microgravity upregulated genes involved in cell proliferation, survival, cardiac differentiation, and contraction, consistent with improved microgravity cultures at the late stage. These results indicate that space microgravity increased proliferation of hiPSC-cardiomyocytes, which had appropriate structure and function. Cryopreserved 3D hiPSC-cardiac progenitors differentiated efficiently in space Microgravity cultures had increased sphere sizes and cellular proliferation Beating cardiomyocytes in microgravity cultures had improved Ca2+ handling Microgravity cultures had upregulated genes in cardiac contraction
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Affiliation(s)
- Antonio Rampoldi
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Parvin Forghani
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Dong Li
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Hyun Hwang
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Lawrence Christian Armand
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | | | | | - Joshua Maxwell
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Kevin Maher
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Chunhui Xu
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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9
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Jiang Z, Zhao Q, Chen L, Luo Y, Shen L, Cao Z, Wang Q. UBR3 promotes inflammation and apoptosis via DUSP1/p38 pathway in the nucleus pulposus cells of patients with intervertebral disc degeneration. Hum Cell 2022; 35:792-802. [PMID: 35332432 DOI: 10.1007/s13577-022-00693-6] [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: 12/20/2021] [Accepted: 03/15/2022] [Indexed: 11/04/2022]
Abstract
Intervertebral disc disease (IDD) is a primary cause of low back pain, affecting 5% of individuals. Previous study have shown that dual-specificity (Thr/Tyr) phosphatase 1 (DUSP1) regulates p38 MAPK activity and DUSP1 level is regulated by ubiquitination. As an E3 ubiquitin-protein ligase, UBR3 has been shown to regulate a variety of biological processes through ubiquitination. However, the role of UBR3/DUSP1/p38 in IDD remains to be elucidated. In the current study, we found that UBR3 was significantly increased in the nucleus pulposus tissues of IDD patients and was correlated with IDD severity. Silencing UBR3 promoted the growth, inhibited apoptosis, and inhibited inflammation in primary NPCs. Mechanism study suggested that UBR3 exerted its effects through p38. Co-immunoprecipitation assay indicated that UBR3 promoted DUSP1 ubiquitination. Overexpression of DUSP1 reversed the effect of UBR3 overexpression. Our data also supported that UBR3 was positively correlated with p-p38, but negatively correlated with DUSP1 in IDD. In summary, UBR3 promotes inflammation and apoptosis via inhibiting the p38 signaling pathway by DUSP1 ubiquitination in the NPCs of IDD patients. These findings highlight the importance of UBR3/DUSP1/p38 signaling pathway in IDD and provide new insights for the prevention and treatment of IDD.
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Affiliation(s)
- Zhenhuan Jiang
- Department of Orthopaedics, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China
| | - Qinghua Zhao
- Department of Orthopaedics, School of Medicine, Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Liang Chen
- Department of Orthopaedics, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China
| | - Yifeng Luo
- Department of Radiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China
| | - Lei Shen
- Department of Orthopaedics, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China
| | - Zhihong Cao
- Department of Radiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China.
| | - Qiang Wang
- Department of Orthopaedics, The Affiliated Yixing Hospital of Jiangsu University, Yixing, China.
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10
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Zhang Y, Zhang Q, Li L, Mu D, Hua K, Ci S, Shen L, Zheng L, Shen B, Guo Z. Arginine methylation of APE1 promotes its mitochondrial translocation to protect cells from oxidative damage. Free Radic Biol Med 2020; 158:60-73. [PMID: 32679368 PMCID: PMC8195256 DOI: 10.1016/j.freeradbiomed.2020.06.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 06/09/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is an essential multifunctional protein in mammals that plays critical roles in DNA repair and redox signaling within the cell. Impaired APE1 function or dysregulation is associated with disease susceptibility and poor cancer prognosis. Orchestrated regulatory mechanisms are crucial to ensure its function in a specific subcellular location at specific time. Here, we report arginine methylation as a post-translational modification (PTM) that regulates APE1 translocation to mitochondria in HeLa and HEK-293 cells. Protein arginine methyl-transferase 1 (PRMT1) was shown to methylate APE1 in vitro. Site-directed mutagenesis identified R301 as the major methylation site. We confirmed that APE1 is methylated in cells and that the R301K mutation significantly reduces its methylation. Baseline mitochondrial APE1 levels were low under standard culture conditions, but they could be induced by oxidative agents. Methylation-deficient APE1 showed reduced mitochondrial translocation. Methylation affected the interaction of APE1 with Tom20, translocase of the outer mitochondrial membrane. Methylation-deficient APE1 resulted in increased mitochondrial DNA damage and increased cytochrome c release after stimuli. These data suggest that methylation of APE1 promotes its mitochondrial translocation and protects cells from oxidative damage. This work describes a novel PTM regulation model of APE1 subcellular distribution through arginine methylation.
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Affiliation(s)
- Yilan Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Qi Zhang
- Department of Infectious Disease, Nanjing Liuhe District People's Hospital, Yangzhou University, Nanjing, 211500, China
| | - LuLu Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Dan Mu
- Department of Radiology, Affiliated Drum Tower Hospital, Nanjing University School of Medicine, Nanjing, 210008, China
| | - Ke Hua
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Shusheng Ci
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Lei Shen
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, 91010, USA
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, 91010, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, 91010, USA.
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China.
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11
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Murcia Pienkowski V, Kucharczyk M, Rydzanicz M, Poszewiecka B, Pachota K, Młynek M, Stawiński P, Pollak A, Kosińska J, Wojciechowska K, Lejman M, Cieślikowska A, Wicher D, Stembalska A, Matuszewska K, Materna-Kiryluk A, Gambin A, Chrzanowska K, Krajewska-Walasek M, Płoski R. Breakpoint Mapping of Symptomatic Balanced Translocations Links the EPHA6, KLF13 and UBR3 Genes to Novel Disease Phenotype. J Clin Med 2020; 9:jcm9051245. [PMID: 32344861 PMCID: PMC7287862 DOI: 10.3390/jcm9051245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/19/2020] [Accepted: 04/23/2020] [Indexed: 12/18/2022] Open
Abstract
De novo balanced chromosomal aberrations (BCAs), such as reciprocal translocations and inversions, are genomic aberrations that, in approximately 25% of cases, affect the human phenotype. Delineation of the exact structure of BCAs may provide a precise diagnosis and/or point to new disease loci. We report on six patients with de novo balanced chromosomal translocations (BCTs) and one patient with a de novo inversion, in whom we mapped breakpoints to a resolution of 1 bp, using shallow whole-genome mate pair sequencing. In all seven cases, a disruption of at least one gene was found. In two patients, the phenotypic impact of the disrupted genes is well known (NFIA, ATP7A). In five patients, the aberration damaged genes: PARD3, EPHA6, KLF13, STK24, UBR3, MLLT10 and TLE3, whose influence on the human phenotype is poorly understood. In particular, our results suggest novel candidate genes for retinal degeneration with anophthalmia (EPHA6), developmental delay with speech impairment (KLF13), and developmental delay with brain dysembryoplastic neuroepithelial tumor (UBR3). In conclusion, identification of the exact structure of symptomatic BCTs using next generation sequencing is a viable method for both diagnosis and finding novel disease candidate genes in humans.
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Affiliation(s)
- Victor Murcia Pienkowski
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland; (V.M.P.); (M.R.); (P.S.); (A.P.); (J.K.)
| | - Marzena Kucharczyk
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland; (V.M.P.); (M.R.); (P.S.); (A.P.); (J.K.)
| | - Barbara Poszewiecka
- Institute of Informatics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, 02-097 Warsaw, Poland; (B.P.); (A.G.)
| | - Katarzyna Pachota
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | - Marlena Młynek
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | - Piotr Stawiński
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland; (V.M.P.); (M.R.); (P.S.); (A.P.); (J.K.)
| | - Agnieszka Pollak
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland; (V.M.P.); (M.R.); (P.S.); (A.P.); (J.K.)
| | - Joanna Kosińska
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland; (V.M.P.); (M.R.); (P.S.); (A.P.); (J.K.)
| | - Katarzyna Wojciechowska
- Department of Pediatric Hematology Oncology and Transplantology, University Children’s Hospital, 20-093 Lublin, Poland;
| | - Monika Lejman
- Department of Pediatric Hematology Oncology and Transplantology, Medical University of Lublin, 20-093 Lublin, Poland;
| | - Agata Cieślikowska
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | - Dorota Wicher
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | | | - Karolina Matuszewska
- Department of Medical Genetics, University of Medical Sciences, 60-806 Poznan, Poland; (K.M.); (A.M.-K.)
- Centers for Medical Genetics GENESIS, Grudzieniec, 60-406 Poznan, Poland
| | - Anna Materna-Kiryluk
- Department of Medical Genetics, University of Medical Sciences, 60-806 Poznan, Poland; (K.M.); (A.M.-K.)
- Centers for Medical Genetics GENESIS, Grudzieniec, 60-406 Poznan, Poland
| | - Anna Gambin
- Institute of Informatics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, 02-097 Warsaw, Poland; (B.P.); (A.G.)
| | - Krystyna Chrzanowska
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | - Małgorzata Krajewska-Walasek
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland; (M.K.); (K.P.); (M.M.); (A.C.); (D.W.); (K.C.); (M.K.-W.)
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland; (V.M.P.); (M.R.); (P.S.); (A.P.); (J.K.)
- Correspondence: ; Tel.: +48-22-572-06-95; Fax: +48-22-572-06-96
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12
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Cleavage of the APE1 N-Terminal Domain in Acute Myeloid Leukemia Cells Is Associated with Proteasomal Activity. Biomolecules 2020; 10:biom10040531. [PMID: 32244430 PMCID: PMC7226146 DOI: 10.3390/biom10040531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 02/02/2023] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1), the main mammalian AP-endonuclease for the resolution of DNA damages through the base excision repair (BER) pathway, acts as a multifunctional protein in different key cellular processes. The signals to ensure temporo-spatial regulation of APE1 towards a specific function are still a matter of debate. Several studies have suggested that post-translational modifications (PTMs) act as dynamic molecular mechanisms for controlling APE1 functionality. Interestingly, the N-terminal region of APE1 is a disordered portion functioning as an interface for protein binding, as an acceptor site for PTMs and as a target of proteolytic cleavage. We previously demonstrated a cytoplasmic accumulation of truncated APE1 in acute myeloid leukemia (AML) cells in association with a mutated form of nucleophosmin having aberrant cytoplasmic localization (NPM1c+). Here, we mapped the proteolytic sites of APE1 in AML cells at Lys31 and Lys32 and showed that substitution of Lys27, 31, 32 and 35 with alanine impairs proteolysis. We found that the loss of the APE1 N-terminal domain in AML cells is dependent on the proteasome, but not on granzyme A/K as described previously. The present work identified the proteasome as a contributing machinery involved in APE1 cleavage in AML cells, suggesting that acetylation can modulate this process.
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13
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Bennett L, Madders ECET, Parsons JL. HECTD1 promotes base excision repair in nucleosomes through chromatin remodelling. Nucleic Acids Res 2020; 48:1301-1313. [PMID: 31799632 PMCID: PMC7026656 DOI: 10.1093/nar/gkz1129] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/12/2019] [Accepted: 11/21/2019] [Indexed: 02/03/2023] Open
Abstract
Base excision repair (BER) is the major cellular DNA repair pathway that recognises and excises damaged DNA bases to help maintain genome stability. Whilst the major enzymes and mechanisms co-ordinating BER are well known, the process of BER in chromatin where DNA is compacted with histones, remains unclear. Using reconstituted mononucleosomes containing a site-specific synthetic abasic site (tetrahydrofuran, THF), we demonstrate that the DNA damage is less efficiently incised by recombinant AP endonuclease 1 (APE1) when the DNA backbone is facing the histone core (THF-in) compared to that orientated away (THF-out). However, when utilizing HeLa whole cell extracts, the difference in incision of THF-in versus THF-out is less pronounced suggesting the presence of chromatin remodelling factors that stimulate THF accessibility to APE1. We subsequently purified an activity from HeLa cell extracts and identify this as the E3 ubiquitin ligase, HECTD1. We demonstrate that a recombinant truncated form of HECTD1 can stimulate incision of THF-in by APE1 in vitro by histone ubiquitylation, and that siRNA-mediated depletion of HECTD1 leads to deficiencies in DNA damage repair and decreased cell survival following x-ray irradiation, particularly in normal fibroblasts. Thus, we have now identified HECTD1 as an important factor in promoting BER in chromatin.
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Affiliation(s)
- Laura Bennett
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, 200 London Road, Liverpool L3 9TA, UK
| | - Eleanor C E T Madders
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, 200 London Road, Liverpool L3 9TA, UK
| | - Jason L Parsons
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, 200 London Road, Liverpool L3 9TA, UK
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14
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UCHL3 Regulates Topoisomerase-Induced Chromosomal Break Repair by Controlling TDP1 Proteostasis. Cell Rep 2019; 23:3352-3365. [PMID: 29898404 PMCID: PMC6019701 DOI: 10.1016/j.celrep.2018.05.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 04/17/2018] [Accepted: 05/11/2018] [Indexed: 11/21/2022] Open
Abstract
Genomic damage can feature DNA-protein crosslinks whereby their acute accumulation is utilized to treat cancer and progressive accumulation causes neurodegeneration. This is typified by tyrosyl DNA phosphodiesterase 1 (TDP1), which repairs topoisomerase-mediated chromosomal breaks. Although TDP1 levels vary in multiple clinical settings, the mechanism underpinning this variation is unknown. We reveal that TDP1 is controlled by ubiquitylation and identify UCHL3 as the deubiquitylase that controls TDP1 proteostasis. Depletion of UCHL3 increases TDP1 ubiquitylation and turnover rate and sensitizes cells to TOP1 poisons. Overexpression of UCHL3, but not a catalytically inactive mutant, suppresses TDP1 ubiquitylation and turnover rate. TDP1 overexpression in the topoisomerase therapy-resistant rhabdomyosarcoma is driven by UCHL3 overexpression. In contrast, UCHL3 is downregulated in spinocerebellar ataxia with axonal neuropathy (SCAN1), causing elevated levels of TDP1 ubiquitylation and faster turnover rate. These data establish UCHL3 as a regulator of TDP1 proteostasis and, consequently, a fine-tuner of protein-linked DNA break repair. TDP1 proteostasis is controlled by a UCHL3-dependent ubiquitylation mechanism UCHL3 depletion sensitizes mammalian cells to TOP1 inhibitors Increased TDP1 protein in rhabdomyosarcoma is driven by UCHL3 upregulation Decreased TDP1 protein in spinocerebellar ataxia is driven by UCHL3 downregulation
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15
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Ray S, Rosenberg MI, Chanut-Delalande H, Decaras A, Schwertner B, Toubiana W, Auman T, Schnellhammer I, Teuscher M, Valenti P, Khila A, Klingler M, Payre F. The mlpt/Ubr3/Svb module comprises an ancient developmental switch for embryonic patterning. eLife 2019; 8:e39748. [PMID: 30896406 PMCID: PMC6428570 DOI: 10.7554/elife.39748] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 03/07/2019] [Indexed: 12/30/2022] Open
Abstract
Small open reading frames (smORFs) encoding 'micropeptides' exhibit remarkable evolutionary complexity. Conserved peptides encoded by mille-pattes (mlpt)/polished rice (pri)/tarsal less (tal) are essential for embryo segmentation in Tribolium but, in Drosophila, function in terminal epidermal differentiation and patterning of adult legs. Here, we show that a molecular complex identified in Drosophila epidermal differentiation, comprising Mlpt peptides, ubiquitin-ligase Ubr3 and transcription factor Shavenbaby (Svb), represents an ancient developmental module required for early insect embryo patterning. We find that loss of segmentation function for this module in flies evolved concomitantly with restriction of Svb expression in early Drosophila embryos. Consistent with this observation, artificially restoring early Svb expression in flies causes segmentation defects that depend on mlpt function, demonstrating enduring potency of an ancestral developmental switch despite evolving embryonic patterning modes. These results highlight the evolutionary plasticity of conserved molecular complexes under the constraints of essential genetic networks. Editorial note This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Suparna Ray
- Department of Biology, Developmental BiologyUniversity of Erlangen-NurembergErlangenGermany
| | - Miriam I Rosenberg
- Department of Ecology, Evolution and BehaviorHebrew University of JerusalemJerusalemIsrael
| | | | | | - Barbara Schwertner
- Department of Biology, Developmental BiologyUniversity of Erlangen-NurembergErlangenGermany
| | | | - Tzach Auman
- Department of Ecology, Evolution and BehaviorHebrew University of JerusalemJerusalemIsrael
| | - Irene Schnellhammer
- Department of Biology, Developmental BiologyUniversity of Erlangen-NurembergErlangenGermany
| | - Matthias Teuscher
- Department of Biology, Developmental BiologyUniversity of Erlangen-NurembergErlangenGermany
| | - Philippe Valenti
- Centre de Biologie du Développement, Université Paul Sabatier de ToulouseToulouseFrance
| | | | - Martin Klingler
- Department of Biology, Developmental BiologyUniversity of Erlangen-NurembergErlangenGermany
| | - François Payre
- Centre de Biologie du Développement, Université Paul Sabatier de ToulouseToulouseFrance
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16
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Markkanen E. Not breathing is not an option: How to deal with oxidative DNA damage. DNA Repair (Amst) 2017; 59:82-105. [PMID: 28963982 DOI: 10.1016/j.dnarep.2017.09.007] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 09/20/2017] [Indexed: 02/07/2023]
Abstract
Oxidative DNA damage constitutes a major threat to genetic integrity, and has thus been implicated in the pathogenesis of a wide variety of diseases, including cancer and neurodegeneration. 7,8-dihydro-8oxo-deoxyGuanine (8-oxo-G) is one of the best characterised oxidative DNA lesions, and it can give rise to point mutations due to its miscoding potential that instructs most DNA polymerases (Pols) to preferentially insert Adenine (A) opposite 8-oxo-G instead of the correct Cytosine (C). If uncorrected, A:8-oxo-G mispairs can give rise to C:G→A:T transversion mutations. Cells have evolved a variety of pathways to mitigate the mutational potential of 8-oxo-G that include i) mechanisms to avoid incorporation of oxidized nucleotides into DNA through nucleotide pool sanitisation enzymes (by MTH1, MTH2, MTH3 and NUDT5), ii) base excision repair (BER) of 8-oxo-G in DNA (involving MUTYH, OGG1, Pol λ, and other components of the BER machinery), and iii) faithful bypass of 8-oxo-G lesions during replication (using a switch between replicative Pols and Pol λ). In the following, the fate of 8-oxo-G in mammalian cells is reviewed in detail. The differential origins of 8-oxo-G in DNA and its consequences for genetic stability will be covered. This will be followed by a thorough discussion of the different mechanisms in place to cope with 8-oxo-G with an emphasis on Pol λ-mediated correct bypass of 8-oxo-G during MUTYH-initiated BER as well as replication across 8-oxo-G. Furthermore, the multitude of mechanisms in place to regulate key proteins involved in 8-oxo-G repair will be reviewed. Novel functions of 8-oxo-G as an epigenetic-like regulator and insights into the repair of 8-oxo-G within the cellular context will be touched upon. Finally, a discussion will outline the relevance of 8-oxo-G and the proteins involved in dealing with 8-oxo-G to human diseases with a special emphasis on cancer.
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Affiliation(s)
- Enni Markkanen
- Institute of Veterinary Pharmacology and Toxicology, Vetsuisse Faculty, University of Zürich, Winterthurerstr. 260, 8057 Zürich, Switzerland.
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17
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Ciechanover A, Kwon YT. Protein Quality Control by Molecular Chaperones in Neurodegeneration. Front Neurosci 2017; 11:185. [PMID: 28428740 PMCID: PMC5382173 DOI: 10.3389/fnins.2017.00185] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/20/2017] [Indexed: 12/14/2022] Open
Abstract
Protein homeostasis (proteostasis) requires the timely degradation of misfolded proteins and their aggregates by protein quality control (PQC), of which molecular chaperones are an essential component. Compared with other cell types, PQC in neurons is particularly challenging because they have a unique cellular structure with long extensions. Making it worse, neurons are postmitotic, i.e., cannot dilute toxic substances by division, and, thus, are highly sensitive to misfolded proteins, especially as they age. Failure in PQC is often associated with neurodegenerative diseases, such as Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), and prion disease. In fact, many neurodegenerative diseases are considered to be protein misfolding disorders. To prevent the accumulation of disease-causing aggregates, neurons utilize a repertoire of chaperones that recognize misfolded proteins through exposed hydrophobic surfaces and assist their refolding. If such an effort fails, chaperones can facilitate the degradation of terminally misfolded proteins through either the ubiquitin (Ub)-proteasome system (UPS) or the autophagy-lysosome system (hereafter autophagy). If soluble, the substrates associated with chaperones, such as Hsp70, are ubiquitinated by Ub ligases and degraded through the proteasome complex. Some misfolded proteins carrying the KFERQ motif are recognized by the chaperone Hsc70 and delivered to the lysosomal lumen through a process called, chaperone-mediated autophagy (CMA). Aggregation-prone misfolded proteins that remain unprocessed are directed to macroautophagy in which cargoes are collected by adaptors, such as p62/SQSTM-1/Sequestosome-1, and delivered to the autophagosome for lysosomal degradation. The aggregates that have survived all these refolding/degradative processes can still be directly dissolved, i.e., disaggregated by chaperones. Studies have shown that molecular chaperones alleviate the pathogenic symptoms by neurodegeneration-causing protein aggregates. Chaperone-inducing drugs and anti-aggregation drugs are actively exploited for beneficial effects on symptoms of disease. Here, we discuss how chaperones protect misfolded proteins from aggregation and mediate the degradation of terminally misfolded proteins in collaboration with cellular degradative machinery. The topics also include therapeutic approaches to improve the expression and turnover of molecular chaperones and to develop anti-aggregation drugs.
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Affiliation(s)
- Aaron Ciechanover
- Department of Biomedical Sciences, Protein Metabolism Medical Research Center, College of Medicine, Seoul National UniversitySeoul, South Korea.,Technion Integrated Cancer Center, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of TechnologyHaifa, Israel
| | - Yong Tae Kwon
- Department of Biomedical Sciences, Protein Metabolism Medical Research Center, College of Medicine, Seoul National UniversitySeoul, South Korea.,Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National UniversitySeoul, South Korea
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18
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Zhang F, Xiao Y, Wang Y. SILAC-Based Quantitative Proteomic Analysis Unveils Arsenite-Induced Perturbation of Multiple Pathways in Human Skin Fibroblast Cells. Chem Res Toxicol 2017; 30:1006-1014. [PMID: 28140569 DOI: 10.1021/acs.chemrestox.6b00416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Humans are exposed to arsenic species through inhalation, ingestion, and dermal contact, which may lead to skin, liver, and bladder cancers as well as cardiovascular and neurological diseases. The mechanisms underlying the cytotoxic and carcinogenic effects of arsenic species, however, remain incompletely understood. To exploit the mechanisms of toxicity of As(III), we employed stable isotope labeling by amino acids in cell culture (SILAC) together with LC/MS/MS analysis to quantitatively assess the As(III)-induced perturbation of the entire proteome of cultured human skin fibroblast cells. Shotgun proteomic analysis on an LTQ-Orbitrap Velos mass spectrometer facilitated the quantification of 3880 proteins, 130 of which were quantified in both forward and reverse SILAC-labeling experiments and displayed significant alterations (>1.5 fold) upon arsenite treatment. Targeted analysis on a triple-quadrupole mass spectrometer in multiple-reaction monitoring (MRM) mode confirmed the quantification results of some select proteins. Ingenuity pathway analysis revealed the arsenite-induced alteration of more than 10 biological pathways, including the Nrf2-mediated oxidative stress response pathway, which is represented by the upregulation of nine proteins in this pathway. In addition, arsenite induced changes in expression levels of a number of selenoproteins and metallothioneins. Together, the results from the present study painted a more complete picture regarding the biological pathways that are altered in human skin fibroblast cells upon arsenite exposure.
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Affiliation(s)
- Fan Zhang
- Department of Chemistry, University of California , Riverside, California 92521-0403, United States
| | - Yongsheng Xiao
- Department of Chemistry, University of California , Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Department of Chemistry, University of California , Riverside, California 92521-0403, United States
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19
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Rao CV, Asch AS, Yamada HY. Frequently mutated genes/pathways and genomic instability as prevention targets in liver cancer. Carcinogenesis 2016; 38:2-11. [PMID: 27838634 DOI: 10.1093/carcin/bgw118] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 09/16/2016] [Accepted: 11/09/2016] [Indexed: 12/18/2022] Open
Abstract
The incidence of liver cancer has increased in recent years. Worldwide, liver cancer is common: more than 600000 related deaths are estimated each year. In the USA, about 27170 deaths due to liver cancer are estimated for 2016. Liver cancer is highly resistant to conventional chemotherapy and radiotherapy. For all stages combined, the 5-year survival rate is 15-17%, leaving much to be desired for liver cancer prevention and therapy. Heterogeneity, which can originate from genomic instability, is one reason for poor outcome. About 80-90% of liver cancers are hepatocellular carcinoma (HCC), and recent cancer genome sequencing studies have revealed frequently mutated genes in HCC. In this review, we discuss the cause of the tumor heterogeneity based on the functions of genes that are frequently mutated in HCC. We overview the functions of the genes that are most frequently mutated (e.g. TP53, CTNNB1, AXIN1, ARID1A and WWP1) that portray major pathways leading to HCC and identify the roles of these genes in preventing genomic instability. Notably, the pathway analysis suggested that oxidative stress management may be critical to prevent accumulation of DNA damage and further mutations. We propose that both chromosome instability (CIN) and microsatellite instability (MIN) are integral to the hepatic carcinogenesis process leading to heterogeneity in HCC and that the pathways leading to heterogeneity may be targeted for prognosis, prevention and treatment.
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Affiliation(s)
- Chinthalapally V Rao
- Center for Cancer Prevention and Drug Development, Department of Medicine, Hematology/Oncology Section, University of Oklahoma Health Sciences Center (OUHSC), 975 NE 10th Street BRC1207, Oklahoma City, OK 73104, USA and
| | - Adam S Asch
- Stephenson Cancer Center, Department of Medicine, Hematology/Oncology Section, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, OK 73104, USA
| | - Hiroshi Y Yamada
- Center for Cancer Prevention and Drug Development, Department of Medicine, Hematology/Oncology Section, University of Oklahoma Health Sciences Center (OUHSC), 975 NE 10th Street BRC1207, Oklahoma City, OK 73104, USA and
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20
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Sandomenico A, Focà A, Sanguigno L, Caporale A, Focà G, Pignalosa A, Corvino G, Caragnano A, Beltrami AP, Antoniali G, Tell G, Leonardi A, Ruvo M. Monoclonal antibodies against pools of mono- and polyacetylated peptides selectively recognize acetylated lysines within the context of the original antigen. MAbs 2016; 8:1575-1589. [PMID: 27560983 DOI: 10.1080/19420862.2016.1225643] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Post-translational modifications (PTMs) strongly influence the structure and function of proteins. Lysine side chain acetylation is one of the most widespread PTMs, and it plays a major role in several physiological and pathological mechanisms. Protein acetylation may be detected by mass spectrometry (MS), but the use of monoclonal antibodies (mAbs) is a useful and cheaper option. Here, we explored the feasibility of generating mAbs against single or multiple acetylations within the context of a specific sequence. As a model, we used the unstructured N-terminal domain of APE1, which is acetylated on Lys27, Lys31, Lys32 and Lys35. As immunogen, we used a peptide mixture containing all combinations of single or multi-acetylated variants encompassing the 24-39 protein region. Targeted screening of the resulting clones yielded mAbs that bind with high affinity to only the acetylated APE1 peptides and the acetylated protein. No binding was seen with the non-acetylated variant or unrelated acetylated peptides and proteins, suggesting a high specificity for the APE1 acetylated molecules. MAbs could not finely discriminate between the differently acetylated variants; however, they specifically bound the acetylated protein in mammalian cell extracts and in intact cells and tissue slices from both breast cancers and from a patient affected by idiopathic dilated cardiomyopathy. The data suggest that our approach is a rapid and cost-effective method to generate mAbs against specific proteins modified by multiple acetylations or other PTMs.
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Affiliation(s)
- Annamaria Sandomenico
- a Istituto di Biostrutture e Bioimmagini , Consiglio Nazionale delle Ricerche (IBB-CNR) , Napoli , Italy
| | - Annalia Focà
- a Istituto di Biostrutture e Bioimmagini , Consiglio Nazionale delle Ricerche (IBB-CNR) , Napoli , Italy
| | | | - Andrea Caporale
- c Centro Interuniversitario di Ricerca sui Peptidi Bioattivi (CIRPeB) , Napoli , Italy
| | - Giuseppina Focà
- a Istituto di Biostrutture e Bioimmagini , Consiglio Nazionale delle Ricerche (IBB-CNR) , Napoli , Italy
| | - Angelica Pignalosa
- a Istituto di Biostrutture e Bioimmagini , Consiglio Nazionale delle Ricerche (IBB-CNR) , Napoli , Italy
| | | | - Angela Caragnano
- d University of Udine , Department of Medical and Biological Sciences , Udine , Italy
| | | | - Giulia Antoniali
- d University of Udine , Department of Medical and Biological Sciences , Udine , Italy
| | - Gianluca Tell
- d University of Udine , Department of Medical and Biological Sciences , Udine , Italy
| | - Antonio Leonardi
- e University of Napoli "Federico II," Department of Molecular Medicine and Medical Biotechnology , Napoli , Italy
| | - Menotti Ruvo
- a Istituto di Biostrutture e Bioimmagini , Consiglio Nazionale delle Ricerche (IBB-CNR) , Napoli , Italy
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21
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Li T, Giagtzoglou N, Eberl DF, Jaiswal SN, Cai T, Godt D, Groves AK, Bellen HJ. The E3 ligase Ubr3 regulates Usher syndrome and MYH9 disorder proteins in the auditory organs of Drosophila and mammals. eLife 2016; 5. [PMID: 27331610 PMCID: PMC4978524 DOI: 10.7554/elife.15258] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/21/2016] [Indexed: 01/08/2023] Open
Abstract
Myosins play essential roles in the development and function of auditory organs and multiple myosin genes are associated with hereditary forms of deafness. Using a forward genetic screen in Drosophila, we identified an E3 ligase, Ubr3, as an essential gene for auditory organ development. Ubr3 negatively regulates the mono-ubiquitination of non-muscle Myosin II, a protein associated with hearing loss in humans. The mono-ubiquitination of Myosin II promotes its physical interaction with Myosin VIIa, a protein responsible for Usher syndrome type IB. We show that ubr3 mutants phenocopy pathogenic variants of Myosin II and that Ubr3 interacts genetically and physically with three Usher syndrome proteins. The interactions between Myosin VIIa and Myosin IIa are conserved in the mammalian cochlea and in human retinal pigment epithelium cells. Our work reveals a novel mechanism that regulates protein complexes affected in two forms of syndromic deafness and suggests a molecular function for Myosin IIa in auditory organs.
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Affiliation(s)
- Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Nikolaos Giagtzoglou
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Department of Neurology, Baylor College of Medicine, Houston, United States
| | - Daniel F Eberl
- Department of Biology, University of Iowa, Iowa City, United States
| | - Sonal Nagarkar Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Tiantian Cai
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Dorothea Godt
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States
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22
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Choi S, Joo HK, Jeon BH. Dynamic Regulation of APE1/Ref-1 as a Therapeutic Target Protein. Chonnam Med J 2016; 52:75-80. [PMID: 27231670 PMCID: PMC4880582 DOI: 10.4068/cmj.2016.52.2.75] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 11/24/2022] Open
Abstract
Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a multifunctional protein that plays a central role in the cellular response to DNA damage and redox regulation against oxidative stress. APE1/Ref-1 functions in the DNA base excision repair pathway, the redox regulation of several transcription factors, and the control of intracellular redox status through the inhibition of reactive oxygen species (ROS) production. APE1/Ref-1 is predominantly localized in the nucleus; however, its subcellular localization is dynamically regulated and it may be found in the mitochondria or elsewhere in the cytoplasm. Studies have identified a nuclear localization signal and a mitochondrial target sequence in APE1/Ref-1, as well as the involvement of the nuclear export system, as determinants of APE1/Ref-1 subcellular distribution. Recently, it was shown that APE1/Ref-1 is secreted in response to hyperacetylation at specific lysine residues. Additionally, post-translational modifications such as phosphorylation, S-nitrosation, and ubiquitination appear to play a role in fine-tuning the activities and subcellular localization of APE1/Ref-1. In this review, we will introduce the multifunctional role of APE1/Ref-1 and its potential usefulness as a therapeutic target in cancer and cardiovascular disease.
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Affiliation(s)
- Sunga Choi
- Research Institute of Medical Sciences, Department of Physiology, College of Medicine, Chungnam National University, Daejeon, Korea
| | - Hee Kyoung Joo
- Research Institute of Medical Sciences, Department of Physiology, College of Medicine, Chungnam National University, Daejeon, Korea
| | - Byeong Hwa Jeon
- Research Institute of Medical Sciences, Department of Physiology, College of Medicine, Chungnam National University, Daejeon, Korea
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23
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Li T, Fan J, Blanco-Sánchez B, Giagtzoglou N, Lin G, Yamamoto S, Jaiswal M, Chen K, Zhang J, Wei W, Lewis MT, Groves AK, Westerfield M, Jia J, Bellen HJ. Ubr3, a Novel Modulator of Hh Signaling Affects the Degradation of Costal-2 and Kif7 through Poly-ubiquitination. PLoS Genet 2016; 12:e1006054. [PMID: 27195754 PMCID: PMC4873228 DOI: 10.1371/journal.pgen.1006054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 04/25/2016] [Indexed: 12/21/2022] Open
Abstract
Hedgehog (Hh) signaling regulates multiple aspects of metazoan development and tissue homeostasis, and is constitutively active in numerous cancers. We identified Ubr3, an E3 ubiquitin ligase, as a novel, positive regulator of Hh signaling in Drosophila and vertebrates. Hh signaling regulates the Ubr3-mediated poly-ubiquitination and degradation of Cos2, a central component of Hh signaling. In developing Drosophila eye discs, loss of ubr3 leads to a delayed differentiation of photoreceptors and a reduction in Hh signaling. In zebrafish, loss of Ubr3 causes a decrease in Shh signaling in the developing eyes, somites, and sensory neurons. However, not all tissues that require Hh signaling are affected in zebrafish. Mouse UBR3 poly-ubiquitinates Kif7, the mammalian homologue of Cos2. Finally, loss of UBR3 up-regulates Kif7 protein levels and decreases Hh signaling in cultured cells. In summary, our work identifies Ubr3 as a novel, evolutionarily conserved modulator of Hh signaling that boosts Hh in some tissues.
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Affiliation(s)
- Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Junkai Fan
- Markey Cancer Center and Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | | | - Nikolaos Giagtzoglou
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jie Zhang
- Markey Cancer Center and Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Wei Wei
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael T. Lewis
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Andrew K. Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Jianhang Jia
- Markey Cancer Center and Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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24
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Scott TL, Wicker CA, Suganya R, Dhar B, Pittman T, Horbinski C, Izumi T. Polyubiquitination of apurinic/apyrimidinic endonuclease 1 by Parkin. Mol Carcinog 2016; 56:325-336. [PMID: 27148961 DOI: 10.1002/mc.22495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 02/26/2016] [Accepted: 04/13/2016] [Indexed: 01/20/2023]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is an essential protein crucial for repair of oxidized DNA damage not only in genomic DNA but also in mitochondrial DNA. Parkin, a tumor suppressor and Parkinson's disease (PD) associated gene, is an E3 ubiquitin ligase crucial for mitophagy. Although DNA damage is known to induce mitochondrial stress, Parkin's role in regulating DNA repair proteins has not been elucidated. In this study, we examined the possibility of Parkin-dependent ubiquitination of APE1. Ectopically expressed APE1 was degraded by Parkin and PINK1 via polyubiquitination in mouse embryonic fibroblast cells. PD-causing mutations in Parkin and PINK1 abrogated APE1 ubiquitination. Interaction of APE1 with Parkin was observed by co-immunoprecipitation, proximity ligation assay, and co-localization in the cytoplasm. N-terminal deletion of 41 amino acid residues in APE1 significantly reduced the Parkin-dependent APE1 degradation. These results suggested that Parkin directly ubiquitinated N-terminal Lys residues in APE1 in the cytoplasm. Modulation of Parkin and PINK1 activities under mitochondrial or oxidative stress caused moderate but statistically significant decrease of endogenous APE1 in human cell lines including SH-SY5Y, HEK293, and A549 cells. Analyses of glioblastoma tissues showed an inverse relation between the expression levels of APE1 and Parkin. These results suggest that degradation of endogenous APE1 by Parkin occur when cells are stressed to activate Parkin, and imply a role of Parkin in maintaining the quality of APE1, and loss of Parkin may contribute to elevated APE1 levels in glioblastoma. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Timothy L Scott
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
| | - Christina A Wicker
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
| | - Rangaswamy Suganya
- Radiation Oncology, Houston Methodist Research Institute, Houston, Texas
| | - Bithika Dhar
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
| | - Thomas Pittman
- Department of Neurosurgery, University of Kentucky, Lexington, Kentucky
| | - Craig Horbinski
- Departments of Pathology and Neurosurgery, Northwestern University, Chicago, Illinois
| | - Tadahide Izumi
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
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25
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Abstract
Base excision repair (BER) is an essential DNA repair pathway involved in the maintenance of genome stability and thus in the prevention of human diseases, such as premature aging, neurodegenerative diseases, and cancer. Protein posttranslational modifications (PTMs), including acetylation, methylation, phosphorylation, SUMOylation, and ubiquitylation, have emerged as important contributors in controlling cellular BER protein levels, enzymatic activities, protein-protein interactions, and protein cellular localization. These PTMs therefore play key roles in regulating the BER pathway and are consequently crucial for coordinating an efficient cellular DNA damage response. In this review, we summarize the presently available data on characterized PTMs of key BER proteins, the functional consequences of these modifications at the protein level, and also the impact on BER in vitro and in vivo.
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26
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Zanet J, Chanut-Delalande H, Plaza S, Payre F. Small Peptides as Newcomers in the Control of Drosophila Development. Curr Top Dev Biol 2016; 117:199-219. [PMID: 26969979 DOI: 10.1016/bs.ctdb.2015.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Throughout the last century, studies using the fruit fly have contributed to the discovery of many key genetic elements that control animal development. Recent work has shed light on an unexpectedly large number of RNAs that lack the classical hallmarks of protein-coding genes and are thus referred to as noncoding RNAs. However, there is mounting evidence that both mRNA and noncoding RNAs often contain small open reading frames (sORFs/smORFs), which can be translated into peptides. While genome-wide profiling supports a pervasive translation of these noncanonical sORF/smORF/SEP peptides, their functions remain poorly understood. Here, we review recent data obtained in Drosophila demonstrating the overlooked role of smORF peptides in the control of development and adult life. Focusing on a few smORF peptides whose functions have been elucidated recently, we discuss the importance of these newly identified regulatory molecules and how they act to regulate the building and function of the whole organism.
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Affiliation(s)
- J Zanet
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France
| | - H Chanut-Delalande
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France
| | - Serge Plaza
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France.
| | - Francios Payre
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France.
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27
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Poletto M, Legrand AJ, Fletcher SC, Dianov GL. p53 coordinates base excision repair to prevent genomic instability. Nucleic Acids Res 2016; 44:3165-75. [PMID: 26773055 PMCID: PMC4838360 DOI: 10.1093/nar/gkw015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/06/2016] [Indexed: 12/03/2022] Open
Abstract
DNA constantly undergoes chemical modification due to endogenous and exogenous mutagens. The DNA base excision repair (BER) pathway is the frontline mechanism handling the majority of these lesions, and primarily involves a DNA incision and subsequent resealing step. It is imperative that these processes are extremely well-coordinated as unrepaired DNA single strand breaks (SSBs) can be converted to DNA double strand breaks during replication thus triggering genomic instability. However, the mechanism(s) governing the BER process are poorly understood. Here we show that accumulation of unrepaired SSBs triggers a p53/Sp1-dependent downregulation of APE1, the endonuclease responsible for the DNA incision during BER. Importantly, we demonstrate that impaired p53 function, a characteristic of many cancers, leads to a failure of the BER coordination mechanism, overexpression of APE1, accumulation of DNA strand breaks and results in genomic instability. Our data provide evidence for a previously unrecognized mechanism for coordination of BER by p53, and its dysfunction in p53-inactivated cells.
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Affiliation(s)
- Mattia Poletto
- CRUK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Department of Oncology, Old Road Campus Research Building, OX37DQ Oxford, UK
| | - Arnaud J Legrand
- CRUK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Department of Oncology, Old Road Campus Research Building, OX37DQ Oxford, UK
| | - Sally C Fletcher
- CRUK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Department of Oncology, Old Road Campus Research Building, OX37DQ Oxford, UK
| | - Grigory L Dianov
- CRUK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Department of Oncology, Old Road Campus Research Building, OX37DQ Oxford, UK Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Lavrenteva 10, 630090 Novosibirsk, Russia
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28
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Zanet J, Benrabah E, Li T, Pélissier-Monier A, Chanut-Delalande H, Ronsin B, Bellen HJ, Payre F, Plaza S. Pri sORF peptides induce selective proteasome-mediated protein processing. Science 2015; 349:1356-8. [PMID: 26383956 DOI: 10.1126/science.aac5677] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A wide variety of RNAs encode small open-reading-frame (smORF/sORF) peptides, but their functions are largely unknown. Here, we show that Drosophila polished-rice (pri) sORF peptides trigger proteasome-mediated protein processing, converting the Shavenbaby (Svb) transcription repressor into a shorter activator. A genome-wide RNA interference screen identifies an E2-E3 ubiquitin-conjugating complex, UbcD6-Ubr3, which targets Svb to the proteasome in a pri-dependent manner. Upon interaction with Ubr3, Pri peptides promote the binding of Ubr3 to Svb. Ubr3 can then ubiquitinate the Svb N terminus, which is degraded by the proteasome. The C-terminal domains protect Svb from complete degradation and ensure appropriate processing. Our data show that Pri peptides control selectivity of Ubr3 binding, which suggests that the family of sORF peptides may contain an extended repertoire of protein regulators.
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Affiliation(s)
- J Zanet
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France
| | - E Benrabah
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France
| | - T Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - A Pélissier-Monier
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France
| | - H Chanut-Delalande
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France
| | - B Ronsin
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France
| | - H J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA. Department of Molecular and Human Genetics, Howard Hughes Medical Institute, Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - F Payre
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France.
| | - S Plaza
- Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Bâtiment 4R3, 118 route de Narbonne, F-31062 Toulouse, France. CNRS, UMR5547, Centre de Biologie du Développement, F-31062 Toulouse, France.
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29
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Coskun E, Jaruga P, Reddy PT, Dizdaroglu M. Extreme Expression of DNA Repair Protein Apurinic/Apyrimidinic Endonuclease 1 (APE1) in Human Breast Cancer As Measured by Liquid Chromatography and Isotope Dilution Tandem Mass Spectrometry. Biochemistry 2015; 54:5787-90. [PMID: 26359670 DOI: 10.1021/acs.biochem.5b00928] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is a DNA repair protein and plays other important roles. Increased levels of APE1 in cancer have been reported. However, available methods for measuring APE1 levels are indirect and not quantitative. We previously developed an approach using liquid chromatography and tandem mass spectrometry with isotope dilution to accurately measure APE1 levels. Here, we applied this methodology to measure APE1 levels in normal and cancerous human breast tissues. Extreme expression of APE1 in malignant tumors was observed, suggesting that breast cancer cells may require APE1 for survival. Accurate measurement of APE1 may be essential for the development of novel treatment strategies and APE1 inhibitors as anticancer drugs.
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Affiliation(s)
- Erdem Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.,Department of Toxicology, Faculty of Pharmacy, Gazi University , Ankara, Turkey
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Prasad T Reddy
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
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30
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Zhao C, Wang L, Ma X, Zhu W, Yao L, Cui Y, Liu Y, Li J, Liang X, Sun Y, Li L, Chen YH. Cardiac Nav 1.5 is modulated by ubiquitin protein ligase E3 component n-recognin UBR3 and 6. J Cell Mol Med 2015; 19:2143-52. [PMID: 26059563 PMCID: PMC4568919 DOI: 10.1111/jcmm.12588] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/03/2015] [Indexed: 11/29/2022] Open
Abstract
The voltage-gated Na+ channel Nav1.5 is essential for action potential (AP) formation and electrophysiological homoeostasis in the heart. The ubiquitin–proteasome system (UPS) is a major degradative system for intracellular proteins including ion channels. The ubiquitin protein ligase E3 component N-recognin (UBR) family is a part of the UPS; however, their roles in regulating cardiac Nav1.5 channels remain elusive. Here, we found that all of the UBR members were expressed in cardiomyocytes. Individual knockdown of UBR3 or UBR6, but not of other UBR members, significantly increased Nav1.5 protein levels in neonatal rat ventricular myocytes, and this effect was verified in HEK293T cells expressing Nav1.5 channels. The UBR3/6-dependent regulation of Nav1.5 channels was not transcriptionally mediated, and pharmacological inhibition of protein biosynthesis failed to counteract the increase in Nav1.5 protein caused by UBR3/6 reduction, suggesting a degradative modulation of UBR3/6 on Nav1.5. Furthermore, the effects of UBR3/6 knockdown on Nav1.5 proteins were abolished under the inhibition of proteasome activity, and UBR3/6 knockdown reduced Nav1.5 ubiquitylation. The double UBR3–UBR6 knockdown resulted in comparable increases in Nav1.5 proteins to that observed for single knockdown of either UBR3 or UBR6. Electrophysiological recordings showed that UBR3/6 reduction-mediated increase in Nav1.5 protein enhanced the opening of Nav1.5 channels and thereby the amplitude of the AP. Thus, our findings indicate that UBR3/6 regulate cardiomyocyte Nav1.5 channel protein levels via the ubiquitin–proteasome pathway. It is likely that UBR3/6 have the potential to be a therapeutic target for cardiac arrhythmias.
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Affiliation(s)
- Chunxia Zhao
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lijie Wang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiue Ma
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Weidong Zhu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Lei Yao
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China
| | - Yingyu Cui
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Yi Liu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Jun Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Xingqun Liang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Yunfu Sun
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Li Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Yi-Han Chen
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
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Poletto M, Malfatti MC, Dorjsuren D, Scognamiglio PL, Marasco D, Vascotto C, Jadhav A, Maloney DJ, Wilson DM, Simeonov A, Tell G. Inhibitors of the apurinic/apyrimidinic endonuclease 1 (APE1)/nucleophosmin (NPM1) interaction that display anti-tumor properties. Mol Carcinog 2015; 55:688-704. [PMID: 25865359 DOI: 10.1002/mc.22313] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 02/10/2015] [Accepted: 02/21/2015] [Indexed: 12/23/2022]
Abstract
The apurinic/apyrimidinic endonuclease 1 (APE1) is a protein central to the base excision DNA repair pathway and operates in the modulation of gene expression through redox-dependent and independent mechanisms. Aberrant expression and localization of APE1 in tumors are recurrent hallmarks of aggressiveness and resistance to therapy. We identified and characterized the molecular association between APE1 and nucleophosmin (NPM1), a multifunctional protein involved in the preservation of genome stability and rRNA maturation. This protein-protein interaction modulates subcellular localization and endonuclease activity of APE1. Moreover, we reported a correlation between APE1 and NPM1 expression levels in ovarian cancer, with NPM1 overexpression being a marker of poor prognosis. These observations suggest that tumors that display an augmented APE1/NPM1 association may exhibit increased aggressiveness and resistance. Therefore, targeting the APE1/NPM1 interaction might represent an innovative strategy for the development of anticancer drugs, as tumor cells relying on higher levels of APE1 and NPM1 for proliferation and survival may be more sensitive than untransformed cells. We set up a chemiluminescence-based high-throughput screening assay in order to find small molecules able to interfere with the APE1/NPM1 interaction. This screening led to the identification of a set of bioactive compounds that impair the APE1/NPM1 association in living cells. Interestingly, some of these molecules display anti-proliferative activity and sensitize cells to therapeutically relevant genotoxins. Given the prognostic significance of APE1 and NPM1, these compounds might prove effective in the treatment of tumors that show abundant levels of both proteins, such as ovarian or hepatic carcinomas.
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Affiliation(s)
- Mattia Poletto
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
| | - Matilde C Malfatti
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
| | - Dorjbal Dorjsuren
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland
| | - Pasqualina L Scognamiglio
- Department of Pharmacy, CIRPEB (Centro Interuniversitario di Ricerca sui Peptidi Bioattivi), University of Naples 'Federico II', Naples, Italy.,Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano di Tecnologia (IIT), Naples, Italy
| | - Daniela Marasco
- Department of Pharmacy, CIRPEB (Centro Interuniversitario di Ricerca sui Peptidi Bioattivi), University of Naples 'Federico II', Naples, Italy
| | - Carlo Vascotto
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
| | - Ajit Jadhav
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland
| | - David J Maloney
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Anton Simeonov
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland
| | - Gianluca Tell
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
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Demasi M, Simões V, Bonatto D. Cross-talk between redox regulation and the ubiquitin-proteasome system in mammalian cell differentiation. Biochim Biophys Acta Gen Subj 2014; 1850:1594-606. [PMID: 25450485 DOI: 10.1016/j.bbagen.2014.10.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/24/2014] [Accepted: 10/28/2014] [Indexed: 12/15/2022]
Abstract
BACKGROUND Embryogenesis and stem cell differentiation are complex and orchestrated signaling processes. Reactive oxygen species (ROS) act as essential signal transducers in cellular differentiation, as has been shown through recent discoveries. On the other hand, the ubiquitin-proteasome system (UPS) has long been known to play an important role in all cellular regulated processes, including differentiation. SCOPE OF REVIEW In the present review, we focus on findings that highlight the interplay between redox signaling and the UPS regarding cell differentiation. Through systems biology analyses, we highlight major routes during cardiomyocyte differentiation based on redox signaling and UPS modulation. MAJOR CONCLUSION Oxygen availability and redox signaling are fundamental regulators of cell fate upon differentiation. The UPS plays an important role in the maintenance of pluripotency and the triggering of differentiation. GENERAL SIGNIFICANCE Cellular differentiation has been a matter of intense investigation mainly because of its potential therapeutic applications. Understanding regulatory mechanisms underlying cell differentiation is an important issue. Correspondingly, the role of UPS and regulation of redox processes have been emerged as essential factors to control the fate of cells upon differentiation. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Marilene Demasi
- Laboratory of Biochemistry and Biophysics, Instituto Butantan, São Paulo, SP, Brazil.
| | - Vanessa Simões
- Department of Genetics and Evolutive Biology, IB, Universidade de São Paulo, São Paulo, Brazil
| | - Diego Bonatto
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul., Porto Alegre, RS, Brazil.
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Edmonds MJ, Parsons JL. Regulation of base excision repair proteins by ubiquitylation. Exp Cell Res 2014; 329:132-8. [DOI: 10.1016/j.yexcr.2014.07.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/21/2014] [Accepted: 07/24/2014] [Indexed: 11/26/2022]
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Ubr3 E3 ligase regulates apoptosis by controlling the activity of DIAP1 in Drosophila. Cell Death Differ 2014; 21:1961-70. [PMID: 25146930 DOI: 10.1038/cdd.2014.115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 12/31/2022] Open
Abstract
Apoptosis has essential roles in a variety of cellular and developmental processes. Although the pathway is well studied, how the activities of individual components in the pathway are regulated is less understood. In Drosophila, a key component in apoptosis is Drosophila inhibitor of apoptosis protein 1 (DIAP1), which is required to prevent caspase activation. Here, we demonstrate that Drosophila CG42593 (ubr3), encoding the homolog of mammalian UBR3, has an essential role in regulating the apoptosis pathway. We show that loss of ubr3 activity causes caspase-dependent apoptosis in Drosophila eye and wing discs. Our genetic epistasis analyses show that the apoptosis induced by loss of ubr3 can be suppressed by loss of initiator caspase Drosophila Nedd2-like caspase (Dronc), or by ectopic expression of the apoptosis inhibitor p35, but cannot be rescued by overexpression of DIAP1. Importantly, we show that the activity of Ubr3 in the apoptosis pathway is not dependent on its Ring-domain, which is required for its E3 ligase activity. Furthermore, we find that through the UBR-box domain, Ubr3 physically interacts with the neo-epitope of DIAP1 that is exposed after caspase-mediated cleavage. This interaction promotes the recruitment and ubiquitination of substrate caspases by DIAP1. Together, our data indicate that Ubr3 interacts with DIAP1 and positively regulates DIAP1 activity, possibly by maintaining its active conformation in the apoptosis pathway.
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Nickson CM, Parsons JL. Monitoring regulation of DNA repair activities of cultured cells in-gel using the comet assay. Front Genet 2014; 5:232. [PMID: 25076968 PMCID: PMC4100063 DOI: 10.3389/fgene.2014.00232] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/30/2014] [Indexed: 01/10/2023] Open
Abstract
Base excision repair (BER) is the predominant cellular mechanism by which human cells repair DNA base damage, sites of base loss, and DNA single strand breaks of various complexity, that are generated in their thousands in every human cell per day as a consequence of cellular metabolism and exogenous agents, including ionizing radiation. Over the last three decades the comet assay has been employed in scientific research to examine the cellular response to these types of DNA damage in cultured cells, therefore revealing the efficiency and capacity of BER. We have recently pioneered new research demonstrating an important role for post-translational modifications (particularly ubiquitylation) in the regulation of cellular levels of BER proteins, and that subtle changes (∼20-50%) in protein levels following siRNA knockdown of E3 ubiquitin ligases or deubiquitylation enzymes can manifest in significant changes in DNA repair capacity monitored using the comet assay. For example, we have shown that the E3 ubiquitin ligase Mule, the tumor suppressor protein ARF, and the deubiquitylation enzyme USP47 modulate DNA repair by controlling cellular levels of DNA polymerase β, and also that polynucleotide kinase phosphatase levels are controlled by ATM-dependant phosphorylation and Cul4A-DDB1-STRAP-dependent ubiquitylation. In these studies we employed a modification of the comet assay whereby cultured cells, following DNA damage treatment, are embedded in agarose and allowed to repair in-gel prior to lysis and electrophoresis. Whilst this method does have its limitations, it avoids the extensive cell culture-based processing associated with the traditional approach using attached cells and also allows for the examination of much more precise DNA repair kinetics. In this review we will describe, using this modified comet assay, our accumulating evidence that ubiquitylation-dependant regulation of BER proteins has important consequences for overall cellular DNA repair capacity.
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Affiliation(s)
- Catherine M Nickson
- Department of Molecular and Clinical Cancer Medicine, North West Cancer Research Centre, University of Liverpool Liverpool, UK
| | - Jason L Parsons
- Department of Molecular and Clinical Cancer Medicine, North West Cancer Research Centre, University of Liverpool Liverpool, UK
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Poletto M, Lirussi L, Wilson DM, Tell G. Nucleophosmin modulates stability, activity, and nucleolar accumulation of base excision repair proteins. Mol Biol Cell 2014; 25:1641-52. [PMID: 24648491 PMCID: PMC4019495 DOI: 10.1091/mbc.e13-12-0717] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/19/2014] [Accepted: 03/10/2014] [Indexed: 01/25/2023] Open
Abstract
Nucleophosmin (NPM1) is a multifunctional protein that controls cell growth and genome stability via a mechanism that involves nucleolar-cytoplasmic shuttling. It is clear that NPM1 also contributes to the DNA damage response, yet its exact function is poorly understood. We recently linked NPM1 expression to the functional activation of the major abasic endonuclease in mammalian base excision repair (BER), apurinic/apyrimidinic endonuclease 1 (APE1). Here we unveil a novel role for NPM1 as a modulator of the whole BER pathway by 1) controlling BER protein levels, 2) regulating total BER capacity, and 3) modulating the nucleolar localization of several BER enzymes. We find that cell treatment with the genotoxin cisplatin leads to concurrent relocalization of NPM1 and BER components from nucleoli to the nucleoplasm, and cellular experiments targeting APE1 suggest a role for the redistribution of nucleolar BER factors in determining cisplatin toxicity. Finally, based on the use of APE1 as a representative protein of the BER pathway, our data suggest a function for BER proteins in the regulation of ribogenesis.
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Affiliation(s)
- Mattia Poletto
- Department of Medical and Biological Sciences, University of Udine, Udine 33100, Italy
| | - Lisa Lirussi
- Department of Medical and Biological Sciences, University of Udine, Udine 33100, Italy
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
| | - Gianluca Tell
- Department of Medical and Biological Sciences, University of Udine, Udine 33100, Italy
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Abstract
This perspective reviews the many dimensions of base excision repair from a 10,000 foot vantage point and provides one person's view on where the field is headed. Enzyme function is considered under the lens of X-ray diffraction and single molecule studies. Base excision repair in chromatin and telomeres, regulation of expression and the role of posttranslational modifications are also discussed in the context of enzyme activities, cellular localization and interacting partners. The specialized roles that base excision repair play in transcriptional activation by active demethylation and targeted oxidation as well as how base excision repair functions in the immune processes of somatic hypermutation and class switch recombination and its possible involvement in retroviral infection are also discussed. Finally the complexities of oxidative damage and its repair and its link to neurodegenerative disorders, as well as the role of base excision repair as a tumor suppressor are examined in the context of damage, repair and aging. By outlining the many base excision repair-related mysteries that have yet to be unraveled, hopefully this perspective will stimulate further interest in the field.
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Affiliation(s)
- Susan S Wallace
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, The University of Vermont, 95 Carrigan Drive, Stafford Hall, Burlington, VT 05405-0084, USA.
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Kaur MP, Guggenheim EJ, Pulisciano C, Akbar S, Kershaw RM, Hodges NJ. Cellular accumulation of Cys326-OGG1 protein complexes under conditions of oxidative stress. Biochem Biophys Res Commun 2014; 447:12-8. [PMID: 24680828 PMCID: PMC4005915 DOI: 10.1016/j.bbrc.2014.03.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 03/11/2014] [Indexed: 01/03/2023]
Abstract
Novel use of BiFC to study a component of base excision repair pathway. First time that OGG1 complex formation has been observed inside of cells. Complexes restricted to the Cys326 variant and conditions of oxidative stress. Evidence supports role of OGG1 dimer formation in reduced repair capacity.
The common Ser326Cys polymorphism in the base excision repair protein 8-oxoguanine glycosylase 1 is associated with a reduced capacity to repair oxidative DNA damage particularly under conditions of intracellular oxidative stress and there is evidence that Cys326-OGG1 homozygous individuals have increased susceptibility to specific cancer types. Indirect biochemical studies have shown that reduced repair capacity is related to OGG1 redox modification and also possibly OGG1 dimer formation. In the current study we have used bimolecular fluorescence complementation to study for the first time a component of the base excision repair pathway and applied it to visualise accumulation of Cys326-OGG1 protein complexes in the native cellular environment. Fluorescence was observed both within and around the cell nucleus, was shown to be specific to cells expressing Cys326-OGG1 and only occurred in cells under conditions of cellular oxidative stress following depletion of intracellular glutathione levels by treatment with buthionine sulphoximine. Furthermore, OGG1 complex formation was inhibited by incubation of cells with the thiol reducing agents β-mercaptoethanol and dithiothreitol and the antioxidant dimethylsulfoxide indicating a causative role for oxidative stress in the formation of OGG1 cellular complexes. In conclusion, this study has provided for the first time evidence of redox sensitive Cys326-OGG1 protein accumulation in cells under conditions of intracellular oxidative stress that may be related to the previously reported reduced repair capacity of Cys326-OGG1 specifically under conditions of oxidative stress.
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Affiliation(s)
- M P Kaur
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - E J Guggenheim
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - C Pulisciano
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - S Akbar
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - R M Kershaw
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - N J Hodges
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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Abstract
SIGNIFICANCE Human apurinic/apyrimidinic endonuclease 1 (APE1, also known as REF-1) was isolated based on its ability to cleave at AP sites in DNA or activate the DNA binding activity of certain transcription factors. We review herein topics related to this multi-functional DNA repair and stress-response protein. RECENT ADVANCES APE1 displays homology to Escherichia coli exonuclease III and is a member of the divalent metal-dependent α/β fold-containing phosphoesterase superfamily of enzymes. APE1 has acquired distinct active site and loop elements that dictate substrate selectivity, and a unique N-terminus which at minimum imparts nuclear targeting and interaction specificity. Additional activities ascribed to APE1 include 3'-5' exonuclease, 3'-repair diesterase, nucleotide incision repair, damaged or site-specific RNA cleavage, and multiple transcription regulatory roles. CRITICAL ISSUES APE1 is essential for mouse embryogenesis and contributes to cell viability in a genetic background-dependent manner. Haploinsufficient APE1(+/-) mice exhibit reduced survival, increased cancer formation, and cellular/tissue hyper-sensitivity to oxidative stress, supporting the notion that impaired APE1 function associates with disease susceptibility. Although abnormal APE1 expression/localization has been seen in cancer and neuropathologies, and impaired-function variants have been described, a causal link between an APE1 defect and human disease remains elusive. FUTURE DIRECTIONS Ongoing efforts aim at delineating the biological role(s) of the different APE1 activities, as well as the regulatory mechanisms for its intra-cellular distribution and participation in diverse molecular pathways. The determination of whether APE1 defects contribute to human disease, particularly pathologies that involve oxidative stress, and whether APE1 small-molecule regulators have clinical utility, is central to future investigations.
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Affiliation(s)
- Mengxia Li
- Intramural Research Program, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
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Scott TL, Rangaswamy S, Wicker CA, Izumi T. Repair of oxidative DNA damage and cancer: recent progress in DNA base excision repair. Antioxid Redox Signal 2014; 20:708-26. [PMID: 23901781 PMCID: PMC3960848 DOI: 10.1089/ars.2013.5529] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE Reactive oxygen species (ROS) are generated by exogenous and environmental genotoxins, but also arise from mitochondria as byproducts of respiration in the body. ROS generate DNA damage of which pathological consequence, including cancer is well established. Research efforts are intense to understand the mechanism of DNA base excision repair, the primary mechanism to protect cells from genotoxicity caused by ROS. RECENT ADVANCES In addition to the notion that oxidative DNA damage causes transformation of cells, recent studies have revealed how the mitochondrial deficiencies and ROS generation alter cell growth during the cancer transformation. CRITICAL ISSUES The emphasis of this review is to highlight the importance of the cellular response to oxidative DNA damage during carcinogenesis. Oxidative DNA damage, including 7,8-dihydro-8-oxoguanine, play an important role during the cellular transformation. It is also becoming apparent that the unusual activity and subcellular distribution of apurinic/apyrimidinic endonuclease 1, an essential DNA repair factor/redox sensor, affect cancer malignancy by increasing cellular resistance to oxidative stress and by positively influencing cell proliferation. FUTURE DIRECTIONS Technological advancement in cancer cell biology and genetics has enabled us to monitor the detailed DNA repair activities in the microenvironment. Precise understanding of the intracellular activities of DNA repair proteins for oxidative DNA damage should provide help in understanding how mitochondria, ROS, DNA damage, and repair influence cancer transformation.
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Affiliation(s)
- Timothy L Scott
- Graduate Center for Toxicology, University of Kentucky , Lexington, Kentucky
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41
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Alagoz M, Wells OS, El-Khamisy SF. TDP1 deficiency sensitizes human cells to base damage via distinct topoisomerase I and PARP mechanisms with potential applications for cancer therapy. Nucleic Acids Res 2013; 42:3089-103. [PMID: 24335147 PMCID: PMC3950670 DOI: 10.1093/nar/gkt1260] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Base damage and topoisomerase I (Top1)-linked DNA breaks are abundant forms of endogenous DNA breakage, contributing to hereditary ataxia and underlying the cytotoxicity of a wide range of anti-cancer agents. Despite their frequency, the overlapping mechanisms that repair these forms of DNA breakage are largely unknown. Here, we report that depletion of Tyrosyl DNA phosphodiesterase 1 (TDP1) sensitizes human cells to alkylation damage and the additional depletion of apurinic/apyrimidinic endonuclease I (APE1) confers hypersensitivity above that observed for TDP1 or APE1 depletion alone. Quantification of DNA breaks and clonogenic survival assays confirm a role for TDP1 in response to base damage, independently of APE1. The hypersensitivity to alkylation damage is partly restored by depletion of Top1, illustrating that alkylating agents can trigger cytotoxic Top1-breaks. Although inhibition of PARP activity does not sensitize TDP1-deficient cells to Top1 poisons, it confers increased sensitivity to alkylation damage, highlighting partially overlapping roles for PARP and TDP1 in response to genotoxic challenge. Finally, we demonstrate that cancer cells in which TDP1 is inherently deficient are hypersensitive to alkylation damage and that TDP1 depletion sensitizes glioblastoma-resistant cancer cells to the alkylating agent temozolomide.
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Affiliation(s)
- Meryem Alagoz
- Kreb's Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK, Genome Damage and Stability Center, University of Sussex, Falmer, Brighton, BN1 9RQ, UK and Center of Genomics, Helmy Institute, Zewail City of Science and technology, Giza, Egypt
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Role of the unstructured N-terminal domain of the hAPE1 (human apurinic/apyrimidinic endonuclease 1) in the modulation of its interaction with nucleic acids and NPM1 (nucleophosmin). Biochem J 2013; 452:545-57. [PMID: 23544830 DOI: 10.1042/bj20121277] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The hAPE1 (human apurinic/apyrimidinic endonuclease 1) is an essential enzyme, being the main abasic endonuclease in higher eukaryotes. However, there is strong evidence to show that hAPE1 can directly bind specific gene promoters, thus modulating their transcriptional activity, even in the absence of specific DNA damage. Recent findings, moreover, suggest a role for hAPE1 in RNA processing, which is modulated by the interaction with NPM1 (nucleophosmin). Independent domains account for many activities of hAPE1; however, whereas the endonuclease and the redox-active portions of the protein are well characterized, a better understanding of the role of the unstructured N-terminal region is needed. In the present study, we characterized the requirements for the interaction of hAPE1 with NPM1 and undamaged nucleic acids. We show that DNA/RNA secondary structure has an impact on hAPE1 binding in the absence of damage. Biochemical studies, using the isolated N-terminal region of the protein, reveal that the hAPE1 N-terminal domain represents an evolutionary gain of function, since its composition affects the protein's stability and ability to interact with both nucleic acids and NPM1. Although required, however, this region is not sufficient itself to stably interact with DNA or NPM1.
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43
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Parsons JL, Dianov GL. Co-ordination of base excision repair and genome stability. DNA Repair (Amst) 2013; 12:326-33. [PMID: 23473643 DOI: 10.1016/j.dnarep.2013.02.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 02/13/2013] [Indexed: 12/20/2022]
Abstract
Base excision repair (BER) is a major DNA repair pathway employed in mammalian cells that is required to maintain genome stability, thus preventing several human diseases, such as ageing, neurodegenerative diseases and cancer. This is achieved through the repair of damaged DNA bases, sites of base loss and single strand breaks of varying complexity that are continuously induced endogenously or via exogenous mutagens. Whilst the enzymes involved in BER are now well known and characterised, the role of the co-ordination of BER enzymatic activities in the cellular response to DNA damage and the mechanisms regulating this process are only now being revealed. Post-translational modifications of BER proteins, including ubiquitylation and phosphorylation, are increasingly being identified as key processes that regulate BER. In this review we will summarise recent evidence discovering novel mechanisms that are involved in maintaining genome stability by regulation of the key BER proteins in response to DNA damage.
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Affiliation(s)
- Jason L Parsons
- Department of Molecular and Clinical Cancer Medicine, Cancer Research Centre, University of Liverpool, 200 London Road, Liverpool, L3 9TA, UK
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44
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Lirussi L, Antoniali G, Vascotto C, D'Ambrosio C, Poletto M, Romanello M, Marasco D, Leone M, Quadrifoglio F, Bhakat KK, Scaloni A, Tell G. Nucleolar accumulation of APE1 depends on charged lysine residues that undergo acetylation upon genotoxic stress and modulate its BER activity in cells. Mol Biol Cell 2012; 23:4079-96. [PMID: 22918947 PMCID: PMC3469522 DOI: 10.1091/mbc.e12-04-0299] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The functional importance of APE1 nucleolar accumulation is described. It is shown that acetylation of Lys27–35, affecting local conformation, regulates APE1 function by 1) controlling its interaction with NPM1 and rRNA and its nucleolar accumulation, 2) modulating K6/K7 acetylation status, and 3) promoting APE1 BER activity in cells. Apurinic/apyrimidinic endonuclease 1 (APE1) is the main abasic endonuclease in the base excision repair (BER) pathway of DNA lesions caused by oxidation/alkylation in mammalian cells; within nucleoli it interacts with nucleophosmin and rRNA through N-terminal Lys residues, some of which (K27/K31/K32/K35) may undergo acetylation in vivo. Here we study the functional role of these modifications during genotoxic damage and their in vivo relevance. We demonstrate that cells expressing a specific K-to-A multiple mutant are APE1 nucleolar deficient and are more resistant to genotoxic treatment than those expressing the wild type, although they show impaired proliferation. Of interest, we find that genotoxic treatment induces acetylation at these K residues. We also find that the charged status of K27/K31/K32/K35 modulates acetylation at K6/K7 residues that are known to be involved in the coordination of BER activity through a mechanism regulated by the sirtuin 1 deacetylase. Of note, structural studies show that acetylation at K27/K31/K32/K35 may account for local conformational changes on APE1 protein structure. These results highlight the emerging role of acetylation of critical Lys residues in regulating APE1 functions. They also suggest the existence of cross-talk between different Lys residues of APE1 occurring upon genotoxic damage, which may modulate APE1 subnuclear distribution and enzymatic activity in vivo.
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Affiliation(s)
- Lisa Lirussi
- Department of Medical and Biological Sciences, University of Udine, 33100 Udine, Italy
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45
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Abstract
The N-end rule pathway is a proteolytic system in which N-terminal residues of short-lived proteins are recognized by recognition components (N-recognins) as essential components of degrons, called N-degrons. Known N-recognins in eukaryotes mediate protein ubiquitylation and selective proteolysis by the 26S proteasome. Substrates of N-recognins can be generated when normally embedded destabilizing residues are exposed at the N terminus by proteolytic cleavage. N-degrons can also be generated through modifications of posttranslationally exposed pro-N-degrons of otherwise stable proteins; such modifications include oxidation, arginylation, leucylation, phenylalanylation, and acetylation. Although there are variations in components, degrons, and hierarchical structures, the proteolytic systems based on generation and recognition of N-degrons have been observed in all eukaryotes and prokaryotes examined thus far. The N-end rule pathway regulates homeostasis of various physiological processes, in part, through interaction with small molecules. Here, we review the biochemical mechanisms, structures, physiological functions, and small-molecule-mediated regulation of the N-end rule pathway.
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Affiliation(s)
- Takafumi Tasaki
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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46
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Kim YJ, Kim D, Illuzzi JL, Delaplane S, Su D, Bernier M, Gross ML, Georgiadis MM, Wilson DM. S-glutathionylation of cysteine 99 in the APE1 protein impairs abasic endonuclease activity. J Mol Biol 2011; 414:313-26. [PMID: 22024594 DOI: 10.1016/j.jmb.2011.10.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 10/03/2011] [Accepted: 10/12/2011] [Indexed: 12/24/2022]
Abstract
Human apurinic/apyrimidinic (AP) endonuclease 1 (APE1) is a central participant in the base excision repair pathway, exhibiting AP endonuclease activity that incises the DNA backbone 5' to an abasic site. Besides its prominent role as a DNA repair enzyme, APE1 was separately identified as a protein called redox effector factor 1, which is able to enhance the DNA binding activity of several transcription factors through a thiol-exchange-based reduction-oxidation mechanism. In the present study, we found that human APE1 is S-glutathionylated under conditions of oxidative stress both in the presence of glutathione in vitro and in cells. S-glutathionylated APE1 displayed significantly reduced AP endonuclease activity on abasic-site-containing oligonucleotide substrates, a result stemming from impaired DNA binding capacity. The combination of site-directed mutagenesis, biochemical assays, and mass spectrometric analysis identified Cys99 in human APE1 as the critical residue for the S-glutathionylation that leads to reduced AP endonuclease activity. This modification is reversible by reducing agents, which restore APE1 incision function. Our studies describe a novel posttranslational modification of APE1 that regulates the DNA repair function of the protein.
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Affiliation(s)
- Yun-Jeong Kim
- Laboratory of Molecular Gerontology, Biomedical Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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