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Woods E, Holmes N, Albaba S, Evans IR, Balasubramanian M. ASXL3-related disorder: Molecular phenotyping and comprehensive review providing insights into disease mechanism. Clin Genet 2024; 105:470-487. [PMID: 38420660 DOI: 10.1111/cge.14506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 03/02/2024]
Abstract
ASXL3-related disorder, sometimes referred to as Bainbridge-Ropers syndrome, was first identified as a distinct neurodevelopmental disorder by Bainbridge et al. in 2013. Since then, there have been a number of case series and single case reports published worldwide. A comprehensive review of the literature was carried out. Abstracts were screened, relevant literature was analysed, and descriptions of common phenotypic features were quantified. ASXL3 variants were collated and categorised. Common phenotypic features comprised global developmental delay or intellectual disability (97%), feeding problems (76%), hypotonia (88%) and characteristic facial features (93%). The majority of genetic variants were de novo truncating variants in exon 11 or 12 of the ASXL3 gene. Several gaps in our knowledge of this disorder were identified, namely, underlying pathophysiology and disease mechanism, disease contribution of missense variants, relevance of variant location, prevalence and penetrance data. Clinical information is currently limited by patient numbers and lack of longitudinal data, which this review aims to address.
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Affiliation(s)
- Emily Woods
- Sheffield Clinical Genetics Service, Sheffield Children's Hospital, Sheffield, UK
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
| | - Nicola Holmes
- Sheffield Diagnostic Genetics Service, Sheffield Children's Hospital, Sheffield, UK
| | - Shadi Albaba
- Sheffield Diagnostic Genetics Service, Sheffield Children's Hospital, Sheffield, UK
| | - Iwan R Evans
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
- The Bateson Centre, University of Sheffield, Sheffield, UK
| | - Meena Balasubramanian
- Sheffield Clinical Genetics Service, Sheffield Children's Hospital, Sheffield, UK
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
- The Bateson Centre, University of Sheffield, Sheffield, UK
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2
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Thomas JF, Valencia-Sánchez MI, Tamburri S, Gloor SL, Rustichelli S, Godínez-López V, De Ioannes P, Lee R, Abini-Agbomson S, Gretarsson K, Burg JM, Hickman AR, Sun L, Gopinath S, Taylor HF, Sun ZW, Ezell RJ, Vaidya A, Meiners MJ, Cheek MA, Rice WJ, Svetlov V, Nudler E, Lu C, Keogh MC, Pasini D, Armache KJ. Structural basis of histone H2A lysine 119 deubiquitination by Polycomb repressive deubiquitinase BAP1/ASXL1. SCIENCE ADVANCES 2023; 9:eadg9832. [PMID: 37556531 PMCID: PMC10411902 DOI: 10.1126/sciadv.adg9832] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 07/03/2023] [Indexed: 08/11/2023]
Abstract
Histone H2A lysine 119 (H2AK119Ub) is monoubiquitinated by Polycomb repressive complex 1 and deubiquitinated by Polycomb repressive deubiquitinase complex (PR-DUB). PR-DUB cleaves H2AK119Ub to restrict focal H2AK119Ub at Polycomb target sites and to protect active genes from aberrant silencing. The PR-DUB subunits (BAP1 and ASXL1) are among the most frequently mutated epigenetic factors in human cancers. How PR-DUB establishes specificity for H2AK119Ub over other nucleosomal ubiquitination sites and how disease-associated mutations of the enzyme affect activity are unclear. Here, we determine a cryo-EM structure of human BAP1 and the ASXL1 DEUBAD in complex with a H2AK119Ub nucleosome. Our structural, biochemical, and cellular data reveal the molecular interactions of BAP1 and ASXL1 with histones and DNA that are critical for restructuring the nucleosome and thus establishing specificity for H2AK119Ub. These results further provide a molecular explanation for how >50 mutations in BAP1 and ASXL1 found in cancer can dysregulate H2AK119Ub deubiquitination, providing insight into understanding cancer etiology.
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Affiliation(s)
- Jonathan F. Thomas
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Marco Igor Valencia-Sánchez
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Simone Tamburri
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
- Department of Health Sciences, University of Milan, Via A. di Rudini 8, 20142 Milan, Italy
| | | | - Samantha Rustichelli
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
| | - Victoria Godínez-López
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Pablo De Ioannes
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Rachel Lee
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Stephen Abini-Agbomson
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Kristjan Gretarsson
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | | | | | - Lu Sun
- EpiCypher Inc., Durham, NC 27709, USA
| | | | | | | | | | | | | | | | - William J. Rice
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Vladimir Svetlov
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Chao Lu
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | | | - Diego Pasini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
- Department of Health Sciences, University of Milan, Via A. di Rudini 8, 20142 Milan, Italy
| | - Karim-Jean Armache
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
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3
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Yang FC, Agosto-Peña J. Epigenetic regulation by ASXL1 in myeloid malignancies. Int J Hematol 2023; 117:791-806. [PMID: 37062051 DOI: 10.1007/s12185-023-03586-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/02/2023] [Accepted: 03/22/2023] [Indexed: 04/17/2023]
Abstract
Myeloid malignancies are clonal hematopoietic disorders that are comprised of a spectrum of genetically heterogeneous disorders, including myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML). Myeloid malignancies are characterized by excessive proliferation, abnormal self-renewal, and/or differentiation defects of hematopoietic stem cells (HSCs) and myeloid progenitor cells hematopoietic stem/progenitor cells (HSPCs). Myeloid malignancies can be caused by genetic and epigenetic alterations that provoke key cellular functions, such as self-renewal, proliferation, biased lineage commitment, and differentiation. Advances in next-generation sequencing led to the identification of multiple mutations in myeloid neoplasms, and many new gene mutations were identified as key factors in driving the pathogenesis of myeloid malignancies. The polycomb protein ASXL1 was identified to be frequently mutated in all forms of myeloid malignancies, with mutational frequencies of 20%, 43%, 10%, and 20% in MDS, CMML, MPN, and AML, respectively. Significantly, ASXL1 mutations are associated with a poor prognosis in all forms of myeloid malignancies. The fact that ASXL1 mutations are associated with poor prognosis in patients with CMML, MDS, and AML, points to the possibility that ASXL1 mutation is a key factor in the development of myeloid malignancies. This review summarizes the recent advances in understanding myeloid malignancies with a specific focus on ASXL1 mutations.
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Affiliation(s)
- Feng-Chun Yang
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
- Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
| | - Joel Agosto-Peña
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
- Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
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4
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Thomas JF, Valencia-Sánchez MI, Tamburri S, Gloor SL, Rustichelli S, Godínez-López V, De Ioannes P, Lee R, Abini-Agbomson S, Gretarsson K, Burg JM, Hickman AR, Sun L, Gopinath S, Taylor H, Meiners MJ, Cheek MA, Rice W, Nudler E, Lu C, Keogh MC, Pasini D, Armache KJ. Structural basis of histone H2A lysine 119 deubiquitination by Polycomb Repressive Deubiquitinase BAP1/ASXL1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529554. [PMID: 36865140 PMCID: PMC9980132 DOI: 10.1101/2023.02.23.529554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The maintenance of gene expression patterns during metazoan development is achieved by the actions of Polycomb group (PcG) complexes. An essential modification marking silenced genes is monoubiquitination of histone H2A lysine 119 (H2AK119Ub) deposited by the E3 ubiquitin ligase activity of the non-canonical Polycomb Repressive Complex 1. The Polycomb Repressive Deubiquitinase (PR-DUB) complex cleaves monoubiquitin from histone H2A lysine 119 (H2AK119Ub) to restrict focal H2AK119Ub at Polycomb target sites and to protect active genes from aberrant silencing. BAP1 and ASXL1, subunits that form active PR-DUB, are among the most frequently mutated epigenetic factors in human cancers, underscoring their biological importance. How PR-DUB achieves specificity for H2AK119Ub to regulate Polycomb silencing is unknown, and the mechanisms of most of the mutations in BAP1 and ASXL1 found in cancer have not been established. Here we determine a cryo-EM structure of human BAP1 bound to the ASXL1 DEUBAD domain in complex with a H2AK119Ub nucleosome. Our structural, biochemical, and cellular data reveal the molecular interactions of BAP1 and ASXL1 with histones and DNA that are critical for remodeling the nucleosome and thus establishing specificity for H2AK119Ub. These results further provide a molecular explanation for how >50 mutations in BAP1 and ASXL1 found in cancer can dysregulate H2AK119Ub deubiquitination, providing new insight into understanding cancer etiology. One Sentence Summary We reveal the molecular mechanism of nucleosomal H2AK119Ub deubiquitination by human BAP1/ASXL1.
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Affiliation(s)
- Jonathan F. Thomas
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
- These authors contributed equally
| | - Marco Igor Valencia-Sánchez
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
- These authors contributed equally
| | - Simone Tamburri
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy
- University of Milan, Via A. di Rudini 8, Department of Health Sciences, 20142 Milan, Italy
| | | | - Samantha Rustichelli
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Victoria Godínez-López
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Pablo De Ioannes
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Rachel Lee
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Stephen Abini-Agbomson
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Kristjan Gretarsson
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
| | | | | | - Lu Sun
- EpiCypher Inc., Durham, North Carolina, USA
| | | | | | | | | | - William Rice
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Chao Lu
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
| | | | - Diego Pasini
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy
- University of Milan, Via A. di Rudini 8, Department of Health Sciences, 20142 Milan, Italy
| | - Karim-Jean Armache
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
- Lead contact
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He M, Cao C, Ni Z, Liu Y, Song P, Hao S, He Y, Sun X, Rao Y. PROTACs: great opportunities for academia and industry (an update from 2020 to 2021). Signal Transduct Target Ther 2022; 7:181. [PMID: 35680848 PMCID: PMC9178337 DOI: 10.1038/s41392-022-00999-9] [Citation(s) in RCA: 82] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/25/2022] [Accepted: 04/12/2022] [Indexed: 02/07/2023] Open
Abstract
PROteolysis TArgeting Chimeras (PROTACs) technology is a new protein-degradation strategy that has emerged in recent years. It uses bifunctional small molecules to induce the ubiquitination and degradation of target proteins through the ubiquitin–proteasome system. PROTACs can not only be used as potential clinical treatments for diseases such as cancer, immune disorders, viral infections, and neurodegenerative diseases, but also provide unique chemical knockdown tools for biological research in a catalytic, reversible, and rapid manner. In 2019, our group published a review article “PROTACs: great opportunities for academia and industry” in the journal, summarizing the representative compounds of PROTACs reported before the end of 2019. In the past 2 years, the entire field of protein degradation has experienced rapid development, including not only a large increase in the number of research papers on protein-degradation technology but also a rapid increase in the number of small-molecule degraders that have entered the clinical and will enter the clinical stage. In addition to PROTAC and molecular glue technology, other new degradation technologies are also developing rapidly. In this article, we mainly summarize and review the representative PROTACs of related targets published in 2020–2021 to present to researchers the exciting developments in the field of protein degradation. The problems that need to be solved in this field will also be briefly introduced.
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Affiliation(s)
- Ming He
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Chaoguo Cao
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China.,Tsinghua-Peking Center for Life Sciences, 100084, Beijing, P. R. China
| | - Zhihao Ni
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Yongbo Liu
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Peilu Song
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Shuang Hao
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Yuna He
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Xiuyun Sun
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China
| | - Yu Rao
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, 100084, Beijing, P. R. China. .,School of Pharmaceutical Sciences, Zhengzhou University, 450001, Zhengzhou, China.
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6
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Peng Q, Wan D, Zhou R, Luo H, Wang J, Ren L, Zeng Y, Yu C, Zhang S, Huang X, Peng Y. The biological function of metazoan-specific subunit nuclear factor related to kappaB binding protein of INO80 complex. Int J Biol Macromol 2022; 203:176-183. [PMID: 35093437 DOI: 10.1016/j.ijbiomac.2022.01.155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 12/24/2022]
Abstract
The INO80 chromatin remodeling complex plays an essential role in the regulation of gene transcription, which participate in a variety of important biological processes in cells including DNA repair and DNA replication. Difference from the yeast INO80 complex, metazoan INO80 complex have the specific subunit G, which is known as nuclear factor related to kappaB binding protein (NFRKB). Recently, NFRKB has been received much attention in many aspects, such as DNA repair, cell pluripotency, telomere protection, and protein activity regulation. To dig the new function of metazoan INO80 complex, a better understanding of the role of NFRKB is required. In this review, we provide an overview of the structure and function of NFRKB and discuss its potential role in cancer treatment and telomere regulation. Overall, this review provides an important reference for further research of the INO80 complex and NFRKB.
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Affiliation(s)
- Qiyao Peng
- Chongqing Key Laboratory for Pharmaceutical Metabolism Research, College of Pharmacy, Chongqing Medical University, Chongqing 400016, China; Institute of Chinese Medicine, Hunan Academy of Traditional Chinese Medicine&Hunan University of Chinese Medicine, Changsha 410208, China
| | - Dan Wan
- Institute of Chinese Medicine, Hunan Academy of Traditional Chinese Medicine&Hunan University of Chinese Medicine, Changsha 410208, China
| | - Rongrong Zhou
- Institute of Chinese Medicine, Hunan Academy of Traditional Chinese Medicine&Hunan University of Chinese Medicine, Changsha 410208, China
| | - Hongyu Luo
- Chongqing Key Laboratory of Traditional Chinese Medicine for Prevention and Cure of Metabolic Diseases, College of Traditional Chinese Medicine, Chongqing Medical University, Chongqing 410016, China
| | - Junyi Wang
- Chongqing Key Laboratory for Pharmaceutical Metabolism Research, College of Pharmacy, Chongqing Medical University, Chongqing 400016, China
| | - Lingyan Ren
- School of Safety Engineering, Chongqing University of Science & Technology, Chongqing 401331, China
| | - Yajun Zeng
- Chongqing Key Laboratory for Pharmaceutical Metabolism Research, College of Pharmacy, Chongqing Medical University, Chongqing 400016, China; Department of Pharmacy, Children's Hospital of Chongqing Medical University, Chongqing 400014, China
| | - Chao Yu
- Chongqing Key Laboratory for Pharmaceutical Metabolism Research, College of Pharmacy, Chongqing Medical University, Chongqing 400016, China
| | - Shuihan Zhang
- Institute of Chinese Medicine, Hunan Academy of Traditional Chinese Medicine&Hunan University of Chinese Medicine, Changsha 410208, China
| | - Xuekuan Huang
- Chongqing Key Laboratory of Traditional Chinese Medicine for Prevention and Cure of Metabolic Diseases, College of Traditional Chinese Medicine, Chongqing Medical University, Chongqing 410016, China.
| | - Yongbo Peng
- Chongqing Key Laboratory for Pharmaceutical Metabolism Research, College of Pharmacy, Chongqing Medical University, Chongqing 400016, China; Institute of Chinese Medicine, Hunan Academy of Traditional Chinese Medicine&Hunan University of Chinese Medicine, Changsha 410208, China.
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7
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Song A, Hazlett Z, Abeykoon D, Dortch J, Dillon A, Curtiss J, Martinez SB, Hill CP, Yu C, Huang L, Fushman D, Cohen RE, Yao T. Branched ubiquitin chain binding and deubiquitination by UCH37 facilitate proteasome clearance of stress-induced inclusions. eLife 2021; 10:72798. [PMID: 34761751 PMCID: PMC8635973 DOI: 10.7554/elife.72798] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/10/2021] [Indexed: 12/20/2022] Open
Abstract
UCH37, also known as UCHL5, is a highly conserved deubiquitinating enzyme (DUB) that associates with the 26S proteasome. Recently, it was reported that UCH37 activity is stimulated by branched ubiquitin (Ub) chain architectures. To understand how UCH37 achieves its unique debranching specificity, we performed biochemical and Nuclear Magnetic Resonance (NMR) structural analyses and found that UCH37 is activated by contacts with the hydrophobic patches of both distal Ubs that emanate from a branched Ub. In addition, RPN13, which recruits UCH37 to the proteasome, further enhances branched-chain specificity by restricting linear Ub chains from having access to the UCH37 active site. In cultured human cells under conditions of proteolytic stress, we show that substrate clearance by the proteasome is promoted by both binding and deubiquitination of branched polyubiquitin by UCH37. Proteasomes containing UCH37(C88A), which is catalytically inactive, aberrantly retain polyubiquitinated species as well as the RAD23B substrate shuttle factor, suggesting a defect in recycling of the proteasome for the next round of substrate processing. These findings provide a foundation to understand how proteasome degradation of substrates modified by a unique Ub chain architecture is aided by a DUB.
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Affiliation(s)
- Aixin Song
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Zachary Hazlett
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Dulith Abeykoon
- Department of Chemistry and Biochemistry, University of Maryland, College Park, United States
| | - Jeremy Dortch
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Andrew Dillon
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Justin Curtiss
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Sarah Bollinger Martinez
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, United States
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, United States
| | - David Fushman
- Department of Chemistry and Biochemistry, University of Maryland, College Park, United States
| | - Robert E Cohen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Tingting Yao
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
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8
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Deol KK, Crowe SO, Du J, Bisbee HA, Guenette RG, Strieter ER. Proteasome-Bound UCH37/UCHL5 Debranches Ubiquitin Chains to Promote Degradation. Mol Cell 2020; 80:796-809.e9. [PMID: 33156996 PMCID: PMC7718437 DOI: 10.1016/j.molcel.2020.10.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/13/2020] [Accepted: 10/13/2020] [Indexed: 01/10/2023]
Abstract
The linkage, length, and architecture of ubiquitin (Ub) chains are all important variables in providing tight control over many biological paradigms. There are clear roles for branched architectures in regulating proteasome-mediated degradation, but the proteins that selectively recognize and process these atypical chains are unknown. Here, using synthetic and enzyme-derived ubiquitin chains along with intact mass spectrometry, we report that UCH37/UCHL5, a proteasome-associated deubiquitinase, cleaves K48 branched chains. The activity and selectivity toward branched chains is markedly enhanced by the proteasomal Ub receptor RPN13/ADRM1. Using reconstituted proteasome complexes, we find that chain debranching promotes degradation of substrates modified with branched chains under multi-turnover conditions. These results are further supported by proteome-wide pulse-chase experiments, which show that the loss of UCH37 activity impairs global protein turnover. Our work therefore defines UCH37 as a debranching deubiquitinase important for promoting proteasomal degradation.
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Affiliation(s)
- Kirandeep K Deol
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sean O Crowe
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jiale Du
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Heather A Bisbee
- Molecular & Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Robert G Guenette
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Eric R Strieter
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA; Molecular & Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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9
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Impact of Losing hRpn13 Pru or UCHL5 on Proteasome Clearance of Ubiquitinated Proteins and RA190 Cytotoxicity. Mol Cell Biol 2020; 40:MCB.00122-20. [PMID: 32631902 DOI: 10.1128/mcb.00122-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 06/26/2020] [Indexed: 01/18/2023] Open
Abstract
hRpn13/ADRM1 links substrate recruitment with deubiquitination at the proteasome through its proteasome- and ubiquitin-binding Pru domain and DEUBAD domain, which binds and activates deubiquitinating enzyme (DUB) UCHL5/Uch37. Here, we edit the HCT116 colorectal cancer cell line to delete part of the hRpn13 Pru, producing cells that express truncated hRpn13 (trRpn13), which is competent for UCHL5 binding but defective for proteasome interaction. trRpn13 cells demonstrate reduced levels of proteasome-bound ubiquitinated proteins, indicating that the loss of hRpn13 function at proteasomes cannot be fully compensated for by the two other dedicated substrate receptors (hRpn1 and hRpn10). Previous studies indicated that the loss of full-length hRpn13 causes a corresponding reduction of UCHL5. We find UCHL5 levels unaltered in trRpn13 cells, but hRpn11 is elevated in ΔhRpn13 and trRpn13 cells, perhaps from cell stress. Despite the ∼90 DUBs in human cells, including two others in addition to UCHL5 at the proteasome, we found deletion of UCHL5 from HCT116 cells to cause increased levels of ubiquitinated proteins in whole-cell extract and at proteasomes, suggesting that UCHL5 activity cannot be fully assumed by other DUBs. We also report anticancer molecule RA190, which binds covalently to hRpn13 and UCHL5, to require hRpn13 Pru and not UCHL5 for cytotoxicity.
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10
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Shin JY, Muniyappan S, Tran NN, Park H, Lee SB, Lee BH. Deubiquitination Reactions on the Proteasome for Proteasome Versatility. Int J Mol Sci 2020; 21:E5312. [PMID: 32726943 PMCID: PMC7432943 DOI: 10.3390/ijms21155312] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/17/2022] Open
Abstract
The 26S proteasome, a master player in proteolysis, is the most complex and meticulously contextured protease in eukaryotic cells. While capable of hosting thousands of discrete substrates due to the selective recognition of ubiquitin tags, this protease complex is also dynamically checked through diverse regulatory mechanisms. The proteasome's versatility ensures precise control over active proteolysis, yet prevents runaway or futile degradation of many essential cellular proteins. Among the multi-layered processes regulating the proteasome's proteolysis, deubiquitination reactions are prominent because they not only recycle ubiquitins, but also impose a critical checkpoint for substrate degradation on the proteasome. Of note, three distinct classes of deubiquitinating enzymes-USP14, RPN11, and UCH37-are associated with the 19S subunits of the human proteasome. Recent biochemical and structural studies suggest that these enzymes exert dynamic influence over proteasome output with limited redundancy, and at times act in opposition. Such distinct activities occur spatially on the proteasome, temporally through substrate processing, and differentially for ubiquitin topology. Therefore, deubiquitinating enzymes on the proteasome may fine-tune the degradation depending on various cellular contexts and for dynamic proteolysis outcomes. Given that the proteasome is among the most important drug targets, the biology of proteasome-associated deubiquitination should be further elucidated for its potential targeting in human diseases.
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Affiliation(s)
- Ji Yeong Shin
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Center for Cell Fate Reprogramming & Control, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Srinivasan Muniyappan
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
| | - Non-Nuoc Tran
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Center for Cell Fate Reprogramming & Control, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Hyeonjeong Park
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
| | - Sung Bae Lee
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Byung-Hoon Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Center for Cell Fate Reprogramming & Control, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
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11
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Xia YK, Zeng YR, Zhang ML, Liu P, Liu F, Zhang H, He CX, Sun YP, Zhang JY, Zhang C, Song L, Ding C, Tang YJ, Yang Z, Yang C, Wang P, Guan KL, Xiong Y, Ye D. Tumor-derived neomorphic mutations in ASXL1 impairs the BAP1-ASXL1-FOXK1/K2 transcription network. Protein Cell 2020; 12:557-577. [PMID: 32683582 PMCID: PMC8225741 DOI: 10.1007/s13238-020-00754-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 06/17/2020] [Indexed: 12/27/2022] Open
Abstract
Additional sex combs-like 1 (ASXL1) interacts with BRCA1-associated protein 1 (BAP1) deubiquitinase to oppose the polycomb repressive complex 1 (PRC1)-mediated histone H2A ubiquitylation. Germline BAP1 mutations are found in a spectrum of human malignancies, while ASXL1 mutations recurrently occur in myeloid neoplasm and are associated with poor prognosis. Nearly all ASXL1 mutations are heterozygous frameshift or nonsense mutations in the middle or to a less extent the C-terminal region, resulting in the production of C-terminally truncated mutant ASXL1 proteins. How ASXL1 regulates specific target genes and how the C-terminal truncation of ASXL1 promotes leukemogenesis are unclear. Here, we report that ASXL1 interacts with forkhead transcription factors FOXK1 and FOXK2 to regulate a subset of FOXK1/K2 target genes. We show that the C-terminally truncated mutant ASXL1 proteins are expressed at much higher levels than the wild-type protein in ASXL1 heterozygous leukemia cells, and lose the ability to interact with FOXK1/K2. Specific deletion of the mutant allele eliminates the expression of C-terminally truncated ASXL1 and increases the association of wild-type ASXL1 with BAP1, thereby restoring the expression of BAP1-ASXL1-FOXK1/K2 target genes, particularly those involved in glucose metabolism, oxygen sensing, and JAK-STAT3 signaling pathways. In addition to FOXK1/K2, we also identify other DNA-binding transcription regulators including transcription factors (TFs) which interact with wild-type ASXL1, but not C-terminally truncated mutant. Our results suggest that ASXL1 mutations result in neomorphic alleles that contribute to leukemogenesis at least in part through dominantly inhibiting the wild-type ASXL1 from interacting with BAP1 and thereby impairing the function of ASXL1-BAP1-TF in regulating target genes and leukemia cell growth.
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Affiliation(s)
- Yu-Kun Xia
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Yi-Rong Zeng
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Meng-Li Zhang
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China.,Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, 200032, China
| | - Peng Liu
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Fang Liu
- Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Hao Zhang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai, 200032, China.,Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Chen-Xi He
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China
| | - Yi-Ping Sun
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Jin-Ye Zhang
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Cheng Zhang
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Lei Song
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing, 102206, China.,National Center for Protein Sciences (The PHOENIX Center, Beijing), Beijing, 102206, China
| | - Chen Ding
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yu-Jie Tang
- Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zhen Yang
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China
| | - Chen Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai, 200032, China.,Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Pu Wang
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China.,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China
| | - Kun-Liang Guan
- Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Yue Xiong
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, USA
| | - Dan Ye
- Huashan Hospital, Fudan University, and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, and the Shanghai Key Laboratory of Medical Epigenetics, and the Key Laboratory of Metabolism and Molecular, Ministry of Education, Shanghai, 200032, China. .,The International Co-Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Shanghai, 200032, China. .,Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, 200032, China.
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12
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Sarodaya N, Karapurkar J, Kim KS, Hong SH, Ramakrishna S. The Role of Deubiquitinating Enzymes in Hematopoiesis and Hematological Malignancies. Cancers (Basel) 2020; 12:E1103. [PMID: 32354135 PMCID: PMC7281754 DOI: 10.3390/cancers12051103] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/11/2020] [Accepted: 04/26/2020] [Indexed: 12/24/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are responsible for the production of blood cells throughout the human lifespan. Single HSCs can give rise to at least eight distinct blood-cell lineages. Together, hematopoiesis, erythropoiesis, and angiogenesis coordinate several biological processes, i.e., cellular interactions during development and proliferation, guided migration, lineage programming, and reprogramming by transcription factors. Any dysregulation of these processes can result in hematological disorders and/or malignancies. Several studies of the molecular mechanisms governing HSC maintenance have demonstrated that protein regulation by the ubiquitin proteasomal pathway is crucial for normal HSC function. Recent studies have shown that reversal of ubiquitination by deubiquitinating enzymes (DUBs) plays an equally important role in hematopoiesis; however, information regarding the biological function of DUBs is limited. In this review, we focus on recent discoveries about the physiological roles of DUBs in hematopoiesis, erythropoiesis, and angiogenesis and discuss the DUBs associated with common hematological disorders and malignancies, which are potential therapeutic drug targets.
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Affiliation(s)
- Neha Sarodaya
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (J.K.); (K.-S.K.)
| | - Janardhan Karapurkar
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (J.K.); (K.-S.K.)
| | - Kye-Seong Kim
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (J.K.); (K.-S.K.)
- College of Medicine, Hanyang University, Seoul 04763, Korea
| | - Seok-Ho Hong
- Department of Internal Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Suresh Ramakrishna
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (J.K.); (K.-S.K.)
- College of Medicine, Hanyang University, Seoul 04763, Korea
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13
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Asada S, Fujino T, Goyama S, Kitamura T. The role of ASXL1 in hematopoiesis and myeloid malignancies. Cell Mol Life Sci 2019; 76:2511-2523. [PMID: 30927018 PMCID: PMC11105736 DOI: 10.1007/s00018-019-03084-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 03/18/2019] [Accepted: 03/25/2019] [Indexed: 12/19/2022]
Abstract
Recent high-throughput genome-wide sequencing studies have identified recurrent somatic mutations in myeloid neoplasms. An epigenetic regulator, Additional sex combs-like 1 (ASXL1), is one of the most frequently mutated genes in all subtypes of myeloid malignancies. ASXL1 mutations are also frequently detected in clonal hematopoiesis, which is associated with an increased risk of mortality. Therefore, it is important to understand how ASXL1 mutations contribute to clonal expansion and myeloid transformation in hematopoietic cells. Studies using ASXL1-depleted human hematopoietic cells and Asxl1 knockout mice have shown that deletion of wild-type ASXL1 protein leads to impaired hematopoiesis and accelerates myeloid malignancies via loss of interaction with polycomb repressive complex 2 proteins. On the other hand, ASXL1 mutations in myeloid neoplasms typically occur near the last exon and result in the expression of C-terminally truncated mutant ASXL1 protein. Biological studies and biochemical analyses of this variant have shed light on its dominant-negative and gain-of-function features in myeloid transformation via a variety of epigenetic changes. Based on these results, it would be possible to establish novel promising therapeutic strategies for myeloid malignancies harboring ASXL1 mutations by blocking interactions between ASXL1 and associating epigenetic regulators. Here, we summarize the clinical implications of ASXL1 mutations, the role of wild-type ASXL1 in normal hematopoiesis, and oncogenic functions of mutant ASXL1 in myeloid neoplasms.
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Affiliation(s)
- Shuhei Asada
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Takeshi Fujino
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Susumu Goyama
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Toshio Kitamura
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan.
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14
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Chen X, Ebelle DL, Wright BJ, Sridharan V, Hooper E, Walters KJ. Structure of hRpn10 Bound to UBQLN2 UBL Illustrates Basis for Complementarity between Shuttle Factors and Substrates at the Proteasome. J Mol Biol 2019; 431:939-955. [PMID: 30664872 PMCID: PMC6389388 DOI: 10.1016/j.jmb.2019.01.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/07/2018] [Accepted: 01/11/2019] [Indexed: 12/14/2022]
Abstract
The 26S proteasome is a highly complex 2.5-MDa molecular machine responsible for regulated protein degradation. Proteasome substrates are typically marked by ubiquitination for recognition at receptor sites contributed by Rpn1/S2/PSMD2, Rpn10/S5a, and Rpn13/Adrm1. Each receptor site can bind substrates directly by engaging conjugated ubiquitin chains or indirectly by binding to shuttle factors Rad23/HR23, Dsk2/PLIC/UBQLN, or Ddi1, which contain a ubiquitin-like domain (UBL) that adopts the ubiquitin fold. Previous structural studies have defined how each of the proteasome receptor sites binds to ubiquitin chains as well as some of the interactions that occur with the shuttle factors. Here, we define how hRpn10 binds to the UBQLN2 UBL domain, solving the structure of this complex by NMR, and determine affinities for each UIM region by a titration experiment. UBQLN2 UBL exhibits 25-fold stronger affinity for the N-terminal UIM-1 over UIM-2 of hRpn10. Moreover, we discover that UBQLN2 UBL is fine-tuned for the hRpn10 UIM-1 site over the UIM-2 site by taking advantage of the additional contacts made available through the longer UIM-1 helix. We also test hRpn10 versatility for the various ubiquitin chains to find less specificity for any particular linkage type compared to hRpn1 and hRpn13, as expected from the flexible linker region that connects the two UIMs; nonetheless, hRpn10 does exhibit some preference for K48 and K11 linkages. Altogether, these results provide new insights into the highly complex and complementary roles of the proteasome receptor sites and shuttle factors.
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Affiliation(s)
- Xiang Chen
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Danielle L Ebelle
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Brandon J Wright
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Vinidhra Sridharan
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Evan Hooper
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Linganore High School, Frederick, MD 21701, USA
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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15
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Clague MJ, Urbé S, Komander D. Breaking the chains: deubiquitylating enzyme specificity begets function. Nat Rev Mol Cell Biol 2019; 20:338-352. [DOI: 10.1038/s41580-019-0099-1] [Citation(s) in RCA: 315] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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16
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De I, Chittock EC, Grötsch H, Miller TCR, McCarthy AA, Müller CW. Structural Basis for the Activation of the Deubiquitinase Calypso by the Polycomb Protein ASX. Structure 2019; 27:528-536.e4. [PMID: 30639226 DOI: 10.1016/j.str.2018.11.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/12/2018] [Accepted: 11/28/2018] [Indexed: 11/16/2022]
Abstract
Ubiquitin C-terminal hydrolase deubiquitinase BAP1 is an essential tumor suppressor involved in cell growth control, DNA damage response, and transcriptional regulation. As part of the Polycomb repression machinery, BAP1 is activated by the deubiquitinase adaptor domain of ASXL1 mediating gene repression by cleaving ubiquitin (Ub) from histone H2A in nucleosomes. The molecular mechanism of BAP1 activation by ASXL1 remains elusive, as no structures are available for either BAP1 or ASXL1. Here, we present the crystal structure of the BAP1 ortholog from Drosophila melanogaster, named Calypso, bound to its activator, ASX, homolog of ASXL1. Based on comparative structural and functional analysis, we propose a model for Ub binding by Calypso/ASX, uncover decisive structural elements responsible for ASX-mediated Calypso activation, and characterize the interaction with ubiquitinated nucleosomes. Our results give molecular insight into Calypso function and its regulation by ASX and provide the opportunity for the rational design of mechanism-based therapeutics to treat human BAP1/ASXL1-related tumors.
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Affiliation(s)
- Inessa De
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Emily C Chittock
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, 69120 Heidelberg, Germany
| | - Helga Grötsch
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Thomas C R Miller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Andrew A McCarthy
- European Molecular Biology Laboratory (EMBL), Grenoble Outstation, BP 181, 38042 Grenoble, France
| | - Christoph W Müller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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17
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Asada S, Kitamura T. Aberrant histone modifications induced by mutant ASXL1 in myeloid neoplasms. Int J Hematol 2018; 110:179-186. [PMID: 30515738 DOI: 10.1007/s12185-018-2563-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 11/19/2018] [Indexed: 12/11/2022]
Abstract
An epigenetic modulator Additional sex combs-like 1 (ASXL1) is recurrently mutated in myeloid neoplasms such as myelodysplastic syndromes (MDS), acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPNs). ASXL1 mutations are also frequently detected in clonal hematopoiesis with indeterminate potential (CHIP), which is the clonal expansion of premalignant hematopoietic cells without any evidence of hematological malignancies. Thus, understanding the roles of ASXL1 in hematopoiesis and myeloid neoplasms is a clinically crucial issue. ASXL1 mutations in hematological neoplasms are typically frameshift or nonsense mutations and occur near the 5' end of the last exon, thereby the transcripts would escape from nonsense-mediated decay, Indeed, we identified the C-terminally truncated mutant protein of ASXL1 in several cell lines derived from patients with myeloid leukemia. In mouse models, expression of the mutant ASXL1 results in impaired hematopoiesis and promotes development of myeloid neoplasms. In addition, recent findings from biochemical analysis have demonstrated that the mutant ASXL1 protein gains new functions including enhancing catalytic activity of BRCA1-associated protein 1 (BAP1), resulting in reduction of H2AK119ub and aberrant gene expression essential for myeloid transformation. In this review, we will focus on the pivotal roles of the mutant ASXL1 on histone modifications and myeloid transformation.
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Affiliation(s)
- Shuhei Asada
- Division of Cellular Therapy, Advanced Clinical Research Center, Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Toshio Kitamura
- Division of Cellular Therapy, Advanced Clinical Research Center, Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan.
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18
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Daou S, Barbour H, Ahmed O, Masclef L, Baril C, Sen Nkwe N, Tchelougou D, Uriarte M, Bonneil E, Ceccarelli D, Mashtalir N, Tanji M, Masson JY, Thibault P, Sicheri F, Yang H, Carbone M, Therrien M, Affar EB. Monoubiquitination of ASXLs controls the deubiquitinase activity of the tumor suppressor BAP1. Nat Commun 2018; 9:4385. [PMID: 30349006 PMCID: PMC6197237 DOI: 10.1038/s41467-018-06854-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 09/19/2018] [Indexed: 12/21/2022] Open
Abstract
The tumor suppressor and deubiquitinase (DUB) BAP1 and its Drosophila ortholog Calypso assemble DUB complexes with the transcription regulators Additional sex combs-like (ASXL1, ASXL2, ASXL3) and Asx respectively. ASXLs and Asx use their DEUBiquitinase ADaptor (DEUBAD) domain to stimulate BAP1/Calypso DUB activity. Here we report that monoubiquitination of the DEUBAD is a general feature of ASXLs and Asx. BAP1 promotes DEUBAD monoubiquitination resulting in an increased stability of ASXL2, which in turn stimulates BAP1 DUB activity. ASXL2 monoubiquitination is directly catalyzed by UBE2E family of Ubiquitin-conjugating enzymes and regulates mammalian cell proliferation. Remarkably, Calypso also regulates Asx monoubiquitination and transgenic flies expressing monoubiquitination-defective Asx mutant exhibit developmental defects. Finally, the protein levels of ASXL2, BAP1 and UBE2E enzymes are highly correlated in mesothelioma tumors suggesting the importance of this signaling axis for tumor suppression. We propose that monoubiquitination orchestrates a molecular symbiosis relationship between ASXLs and BAP1.
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Affiliation(s)
- Salima Daou
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada.,Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, M5G 1X5, Canada
| | - Haithem Barbour
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Oumaima Ahmed
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Louis Masclef
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Caroline Baril
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, University of Montréal, Montréal, QC, H3T 1J4, Canada
| | - Nadine Sen Nkwe
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Daméhan Tchelougou
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Maxime Uriarte
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Eric Bonneil
- Institute for Research in Immunology and Cancer, Laboratory of Proteomics and Bioanalytical Mass Spectrometry, University of Montréal, Montréal, QC, H3T 1J4, Canada
| | - Derek Ceccarelli
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, M5G 1X5, Canada
| | - Nazar Mashtalir
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada
| | - Mika Tanji
- University of Hawaii Cancer Center, University of Hawaii, Honolulu, HI, 96813, USA
| | - Jean-Yves Masson
- CHU de Quebec Research Center (Oncology Axis), Laval University Cancer Research Center, 9 McMahon, Quebec, PQ, G1R 2J6, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Laboratory of Proteomics and Bioanalytical Mass Spectrometry, University of Montréal, Montréal, QC, H3T 1J4, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, M5G 1X5, Canada
| | - Haining Yang
- University of Hawaii Cancer Center, University of Hawaii, Honolulu, HI, 96813, USA
| | - Michele Carbone
- University of Hawaii Cancer Center, University of Hawaii, Honolulu, HI, 96813, USA
| | - Marc Therrien
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, University of Montréal, Montréal, QC, H3T 1J4, Canada. .,Département de pathologie et biologie cellulaire, University of Montréal, Montréal, QC, H3C 3J7, Canada.
| | - El Bachir Affar
- Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, QC, H3C 3J7, Canada.
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19
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Nagase R, Inoue D, Pastore A, Fujino T, Hou HA, Yamasaki N, Goyama S, Saika M, Kanai A, Sera Y, Horikawa S, Ota Y, Asada S, Hayashi Y, Kawabata KC, Takeda R, Tien HF, Honda H, Abdel-Wahab O, Kitamura T. Expression of mutant Asxl1 perturbs hematopoiesis and promotes susceptibility to leukemic transformation. J Exp Med 2018; 215:1729-1747. [PMID: 29643185 PMCID: PMC5987913 DOI: 10.1084/jem.20171151] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 12/24/2017] [Accepted: 03/01/2018] [Indexed: 01/11/2023] Open
Abstract
Nagase and Inoue et al. generated a novel Asxl1 mutant mouse model to mimic clonal hematopoiesis and myelodysplastic syndromes caused by ASXL1 mutations and elucidated the effects of mutant versus wild-type ASXL1 on hematopoiesis, gene expression, and chromatin state. Additional sex combs like 1 (ASXL1) is frequently mutated in myeloid malignancies and clonal hematopoiesis of indeterminate potential (CHIP). Although loss of ASXL1 promotes hematopoietic transformation, there is growing evidence that ASXL1 mutations might confer an alteration of function. In this study, we identify that physiological expression of a C-terminal truncated Asxl1 mutant in vivo using conditional knock-in (KI) results in myeloid skewing, age-dependent anemia, thrombocytosis, and morphological dysplasia. Although expression of mutant Asxl1 altered the functions of hematopoietic stem cells (HSCs), it maintained their survival in competitive transplantation assays and increased susceptibility to leukemic transformation by co-occurring RUNX1 mutation or viral insertional mutagenesis. KI mice displayed substantial reductions in H3K4me3 and H2AK119Ub without significant reductions in H3K27me3, distinct from the effects of Asxl1 loss. Chromatin immunoprecipitation followed by next-generation sequencing analysis demonstrated opposing effects of wild-type and mutant Asxl1 on H3K4me3. These findings reveal that ASXL1 mutations confer HSCs with an altered epigenome and increase susceptibility for leukemic transformation, presenting a novel model for CHIP.
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Affiliation(s)
- Reina Nagase
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Daichi Inoue
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan .,Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Alessandro Pastore
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Takeshi Fujino
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Hsin-An Hou
- Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Norimasa Yamasaki
- Department of Disease Model, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Susumu Goyama
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Makoto Saika
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Akinori Kanai
- Department of Molecular Oncology and Leukemia Program Project, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Yasuyuki Sera
- Department of Disease Model, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Sayuri Horikawa
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yasunori Ota
- Department of Pathology, Research Hospital, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Shuhei Asada
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yasutaka Hayashi
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kimihito Cojin Kawabata
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Reina Takeda
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Hwei-Fang Tien
- Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Hiroaki Honda
- Department of Disease Model, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.,Field of Human Disease Models, Major in Advanced Life Sciences and Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Toshio Kitamura
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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20
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Ubiquitin recognition of BAP1: understanding its enzymatic function. Biosci Rep 2017; 37:BSR20171099. [PMID: 28935764 PMCID: PMC5665613 DOI: 10.1042/bsr20171099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 09/01/2017] [Accepted: 09/19/2017] [Indexed: 01/10/2023] Open
Abstract
BRCA1-associated protein 1 (BAP1) is a nuclear localizing UCH, having tumor suppressor activity and is widely involved in many crucial cellular processes. BAP1 has garnered attention for its links with cancer, however, the molecular mechanism in the regulation of cancer by BAP1 has not been established. Amongst the four UCHs, only BAP1 and UCHL5 are able to hydrolyze small and large ubiquitin adducts but UCHL5 hydrolyzes only when it is present in the PA700 complex of the proteasome. The ability of BAP1 to cleave large ubiquitin derivatives is because of its relatively longer active-site crossover loop than other UCHs. The mechanism of ubiquitin recognition has not been studied for BAP1. The comparative enzymatic analysis of ubiquitin C-terminal hydrolase L1 (UCHL1), ubiquitin C-terminal hydrolase L3 (UCHL3), ubiquitin C-terminal hydrolase L5 (UCHL5N), and BAP1N has confirmed that enzymatically BAP1 is similar to UCHL5, which corroborates with the bioinformatics analysis done earlier. We have undertaken extensive mutational approaches to gain mechanistic insight into BAP1–ubiquitin interaction. Based on the homology-modeled BAP1 structure, we have identified a few BAP1 residues which possibly play a crucial role in ubiquitin interaction of which a few mutations have been identified in many cancers. Our comparative thermodynamic analysis reveals that BAP1–ubiquitin interaction is majorly driven by entropy factor which is unique amongst UCHs. Our study sheds light on BAP1 interaction with ubiquitin, which will be useful in understanding its enzymatic function.
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21
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Dinan AM, Atkins JF, Firth AE. ASXL gain-of-function truncation mutants: defective and dysregulated forms of a natural ribosomal frameshifting product? Biol Direct 2017; 12:24. [PMID: 29037253 PMCID: PMC5644247 DOI: 10.1186/s13062-017-0195-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/04/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Programmed ribosomal frameshifting (PRF) is a gene expression mechanism which enables the translation of two N-terminally coincident, C-terminally distinct protein products from a single mRNA. Many viruses utilize PRF to control or regulate gene expression, but very few phylogenetically conserved examples are known in vertebrate genes. Additional sex combs-like (ASXL) genes 1 and 2 encode important epigenetic and transcriptional regulatory proteins that control the expression of homeotic genes during key developmental stages. Here we describe an ~150-codon overlapping ORF (termed TF) in ASXL1 and ASXL2 that, with few exceptions, is conserved throughout vertebrates. RESULTS Conservation of the TF ORF, strong suppression of synonymous site variation in the overlap region, and the completely conserved presence of an EH[N/S]Y motif (a known binding site for Host Cell Factor-1, HCF-1, an epigenetic regulatory factor), all indicate that TF is a protein-coding sequence. A highly conserved UCC_UUU_CGU sequence (identical to the known site of +1 ribosomal frameshifting for influenza virus PA-X expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL1. Similarly, a highly conserved RG_GUC_UCU sequence (identical to a known site of -2 ribosomal frameshifting for arterivirus nsp2TF expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL2. CONCLUSIONS Due to a lack of appropriate splice forms, or initiation sites, the most plausible mechanism for translation of the ASXL1 and 2 TF regions is ribosomal frameshifting, resulting in a transframe fusion of the N-terminal half of ASXL1 or 2 to the TF product, termed ASXL-TF. Truncation or frameshift mutants of ASXL are linked to myeloid malignancies and genetic diseases, such as Bohring-Opitz syndrome, likely at least in part as a result of gain-of-function or dominant-negative effects. Our hypothesis now indicates that these disease-associated mutant forms represent overexpressed defective versions of ASXL-TF. REVIEWERS This article was reviewed by Laurence Hurst and Eugene Koonin.
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Affiliation(s)
- Adam M Dinan
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, T12 YT57, Cork, Ireland.,Department of Human Genetics, University of Utah, Salt Lake City, UT, 84112, USA
| | - Andrew E Firth
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, CB2 1QP, UK.
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22
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de Poot SAH, Tian G, Finley D. Meddling with Fate: The Proteasomal Deubiquitinating Enzymes. J Mol Biol 2017; 429:3525-3545. [PMID: 28988953 DOI: 10.1016/j.jmb.2017.09.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/20/2017] [Accepted: 09/26/2017] [Indexed: 01/06/2023]
Abstract
Three deubiquitinating enzymes-Rpn11, Usp14, and Uch37-are associated with the proteasome regulatory particle. These enzymes allow proteasomes to remove ubiquitin from substrates before they are translocated into the core particle to be degraded. Although the translocation channel is too narrow for folded proteins, the force of translocation unfolds them mechanically. As translocation proceeds, ubiquitin chains bound to substrate are drawn to the channel's entry port, where they can impede further translocation. Rpn11, situated over the port, can remove these chains without compromising degradation because substrates must be irreversibly committed to degradation before Rpn11 acts. This coupling between deubiquitination and substrate degradation is ensured by the Ins-1 loop of Rpn11, which controls ubiquitin access to its catalytic site. In contrast to Rpn11, Usp14 and Uch37 can rescue substrates from degradation by promoting substrate dissociation from the proteasome prior to the commitment step. Uch37 is unique in being a component of both the proteasome and a second multisubunit assembly, the INO80 complex. However, only recruitment into the proteasome activates Uch37. Recruitment to the proteasome likewise activates Usp14. However, the influence of Usp14 on the proteasome depends on the substrate, due to its marked preference for proteins that carry multiple ubiquitin chains. Usp14 exerts complex control over the proteasome, suppressing proteasome activity even when inactive in deubiquitination. A major challenge for the field will be to elucidate the specificities of Rpn11, Usp14, and Uch37 in greater depth, employing not only model in vitro substrates but also their endogenous targets.
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Affiliation(s)
- Stefanie A H de Poot
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Geng Tian
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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23
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Molecular architecture of polycomb repressive complexes. Biochem Soc Trans 2017; 45:193-205. [PMID: 28202673 PMCID: PMC5310723 DOI: 10.1042/bst20160173] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/24/2016] [Accepted: 12/02/2016] [Indexed: 01/05/2023]
Abstract
The polycomb group (PcG) proteins are a large and diverse family that epigenetically repress the transcription of key developmental genes. They form three broad groups of polycomb repressive complexes (PRCs) known as PRC1, PRC2 and Polycomb Repressive DeUBiquitinase, each of which modifies and/or remodels chromatin by distinct mechanisms that are tuned by having variable compositions of core and accessory subunits. Until recently, relatively little was known about how the various PcG proteins assemble to form the PRCs; however, studies by several groups have now allowed us to start piecing together the PcG puzzle. Here, we discuss some highlights of recent PcG structures and the insights they have given us into how these complexes regulate transcription through chromatin.
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24
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Affiliation(s)
- Tycho E.T. Mevissen
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - David Komander
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
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25
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Lensink MF, Velankar S, Wodak SJ. Modeling protein-protein and protein-peptide complexes: CAPRI 6th edition. Proteins 2016; 85:359-377. [PMID: 27865038 DOI: 10.1002/prot.25215] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/07/2016] [Accepted: 10/10/2016] [Indexed: 12/19/2022]
Abstract
We present the sixth report evaluating the performance of methods for predicting the atomic resolution structures of protein complexes offered as targets to the community-wide initiative on the Critical Assessment of Predicted Interactions (CAPRI). The evaluation is based on a total of 20,670 predicted models for 8 protein-peptide complexes, a novel category of targets in CAPRI, and 12 protein-protein targets in CAPRI prediction Rounds held during the years 2013-2016. For two of the protein-protein targets, the focus was on the prediction of side-chain conformation and positions of interfacial water molecules. Seven of the protein-protein targets were particularly challenging owing to their multicomponent nature, to conformational changes at the binding site, or to a combination of both. Encouragingly, the very large multiprotein complex with the nucleosome was correctly predicted, and correct models were submitted for the protein-peptide targets, but not for some of the challenging protein-protein targets. Models of acceptable quality or better were obtained for 14 of the 20 targets, including medium quality models for 13 targets and high quality models for 8 targets, indicating tangible progress of present-day computational methods in modeling protein complexes with increased accuracy. Our evaluation suggests that the progress stems from better integration of different modeling tools with docking procedures, as well as the use of more sophisticated evolutionary information to score models. Nonetheless, adequate modeling of conformational flexibility in interacting proteins remains an important area with a crucial need for improvement. Proteins 2017; 85:359-377. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marc F Lensink
- University of Lille, CNRS UMR8576 UGSF, Lille, 59000, France
| | - Sameer Velankar
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, United Kingdom
| | - Shoshana J Wodak
- VIB Structural Biology Research Center, VUB Pleinlaan 2, Brussels, 1050, Belgium
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26
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Vreven T, Pierce BG, Borrman TM, Weng Z. Performance of ZDOCK and IRAD in CAPRI rounds 28-34. Proteins 2016; 85:408-416. [PMID: 27718275 DOI: 10.1002/prot.25186] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/20/2016] [Accepted: 09/29/2016] [Indexed: 11/11/2022]
Abstract
We report the performance of our protein-protein docking pipeline, including the ZDOCK rigid-body docking algorithm, on 19 targets in CAPRI rounds 28-34. Following the docking step, we reranked the ZDOCK predictions using the IRAD scoring function, pruned redundant predictions, performed energy landscape analysis, and utilized our interface prediction approach RCF. In addition, we applied constraints to the search space based on biological information that we culled from the literature, which increased the chance of making a correct prediction. For all but two targets we were able to find and apply biological information and we found the information to be highly accurate, indicating that effective incorporation of biological information is an important component for protein-protein docking. Proteins 2017; 85:408-416. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Thom Vreven
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01605
| | - Brian G Pierce
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01605
| | - Tyler M Borrman
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01605
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01605
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27
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Micol JB, Abdel-Wahab O. The Role of Additional Sex Combs-Like Proteins in Cancer. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a026526. [PMID: 27527698 DOI: 10.1101/cshperspect.a026526] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Additional sex combs-like (ASXL) proteins are mammalian homologs of Addition of sex combs (Asx), a protein that regulates the balance of trithorax and Polycomb function in Drosophila. All three ASXL family members (ASXL1, ASXL2, and ASXL3) are affected by somatic or de novo germline mutations in cancer or rare developmental syndromes, respectively. Although Asx is characterized as a catalytic partner for the deubiquitinase Calypso (or BAP1), there are domains of ASXL proteins that are distinct from Asx and the roles and redundancies of ASXL members are not yet well understood. Moreover, it is not yet fully clarified if commonly encountered ASXL1 mutations result in a loss of protein or stable expression of a truncated protein with dominant-negative or gain-of-function properties. This review summarizes our current knowledge of the biological and functional roles of ASXL members in development, cancer, and transcription.
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Affiliation(s)
- Jean-Baptiste Micol
- Hematology Department, INSERM UMR1170, Gustave Roussy Cancer Campus Grand Paris, Villejuif, France Université Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, Paris, France Human Oncology and Pathogenesis Program and Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program and Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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28
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Chen X, Randles L, Shi K, Tarasov SG, Aihara H, Walters KJ. Structures of Rpn1 T1:Rad23 and hRpn13:hPLIC2 Reveal Distinct Binding Mechanisms between Substrate Receptors and Shuttle Factors of the Proteasome. Structure 2016; 24:1257-1270. [PMID: 27396824 DOI: 10.1016/j.str.2016.05.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/10/2016] [Accepted: 05/25/2016] [Indexed: 12/14/2022]
Abstract
Three receptors (Rpn1/S2/PSMD2, Rpn10/S5a, Rpn13/Adrm1) in the proteasome bind substrates by interacting with conjugated ubiquitin chains and/or shuttle factors (Rad23/HR23, Dsk2/PLIC/ubiquilin, Ddi1) that carry ubiquitinated substrates to proteasomes. We solved the structure of two such receptors with their preferred shuttle factor, namely hRpn13(Pru):hPLIC2(UBL) and scRpn1 T1:scRad23(UBL). We find that ubiquitin folds in Rad23 and Dsk2 are fine-tuned by residue substitutions to achieve high affinity for Rpn1 and Rpn13, respectively. A single substitution in hPLIC2 yields enhanced interactions with the Rpn13 ubiquitin contact surface and sterically blocks hRpn13 binding to its preferred ubiquitin chain type, K48-linked chains. Rpn1 T1 binds two ubiquitins in tandem and we find that Rad23 binds exclusively to the higher-affinity Helix28/Helix30 site. Rad23 contacts at Helix28/Helix30 are optimized compared to ubiquitin by multiple conservative amino acid substitutions. Thus, shuttle factors deliver substrates to proteasomes through fine-tuned ubiquitin-like surfaces.
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Affiliation(s)
- Xiang Chen
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Leah Randles
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Ke Shi
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sergey G Tarasov
- Biophysics Resource, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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29
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BAP1/ASXL1 recruitment and activation for H2A deubiquitination. Nat Commun 2016; 7:10292. [PMID: 26739236 PMCID: PMC4729829 DOI: 10.1038/ncomms10292] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/26/2015] [Indexed: 12/22/2022] Open
Abstract
The deubiquitinating enzyme BAP1 is an important tumor suppressor that has drawn attention in the clinic since its loss leads to a variety of cancers. BAP1 is activated by ASXL1 to deubiquitinate mono-ubiquitinated H2A at K119 in Polycomb gene repression, but the mechanism of this reaction remains poorly defined. Here we show that the BAP1 C-terminal extension is important for H2A deubiquitination by auto-recruiting BAP1 to nucleosomes in a process that does not require the nucleosome acidic patch. This initial encounter-like complex is unproductive and needs to be activated by the DEUBAD domains of ASXL1, ASXL2 or ASXL3 to increase BAP1's affinity for ubiquitin on H2A, to drive the deubiquitination reaction. The reaction is specific for Polycomb modifications of H2A as the complex cannot deubiquitinate the DNA damage-dependent ubiquitination at H2A K13/15. Our results contribute to the molecular understanding of this important tumor suppressor.
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30
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A High Affinity hRpn2-Derived Peptide That Displaces Human Rpn13 from Proteasome in 293T Cells. PLoS One 2015; 10:e0140518. [PMID: 26466095 PMCID: PMC4605517 DOI: 10.1371/journal.pone.0140518] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/28/2015] [Indexed: 01/08/2023] Open
Abstract
Rpn13 is a proteasome ubiquitin receptor that has emerged as a therapeutic target for human cancers. Its ubiquitin-binding activity is confined to an N-terminal Pru (pleckstrin-like receptor for ubiquitin) domain that also docks it into the proteasome, while its C-terminal DEUBAD (DEUBiquitinase ADaptor) domain recruits deubiquitinating enzyme Uch37 to the proteasome. Bis-benzylidine piperidone derivatives that were found to bind covalently to Rpn13 C88 caused the accumulation of polyubiquitinated proteins as well as ER stress-related apoptosis in various cancer cell lines, including bortezomib-resistant multiple myeloma lines. We find that a 38-amino acid peptide derived from the C-terminus of proteasome PC repeat protein hRpn2/PSMD1 binds to hRpn13 Pru domain with 12 nM affinity. By using NMR, we identify the hRpn13-interacting amino acids in this hRpn2 fragment, some of which are conserved among eukaryotes. Importantly, we find the hRpn2-derived peptide to immunoprecipitate endogenous Rpn13 from 293T cells, and to displace it from the proteasome. These findings indicate that this region of hRpn2 is the primary binding site for hRpn13 in the proteasome. Moreover, the hRpn2-derived peptide was no longer able to interact with endogenous hRpn13 when a strictly conserved phenylalanine (F948 in humans) was replaced with arginine or a stop codon, or when Y950 and I951 were substituted with aspartic acid. Finally, over-expression of the hRpn2-derived peptide leads to an increased presence of ubiquitinated proteins in 293T cells. We propose that this hRpn2-derived peptide could be used to develop peptide-based strategies that specifically target hRpn13 function in the proteasome.
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31
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Daou S, Hammond-Martel I, Mashtalir N, Barbour H, Gagnon J, Iannantuono NVG, Nkwe NS, Motorina A, Pak H, Yu H, Wurtele H, Milot E, Mallette FA, Carbone M, Affar EB. The BAP1/ASXL2 Histone H2A Deubiquitinase Complex Regulates Cell Proliferation and Is Disrupted in Cancer. J Biol Chem 2015; 290:28643-63. [PMID: 26416890 DOI: 10.1074/jbc.m115.661553] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Indexed: 01/03/2023] Open
Abstract
The deubiquitinase (DUB) and tumor suppressor BAP1 catalyzes ubiquitin removal from histone H2A Lys-119 and coordinates cell proliferation, but how BAP1 partners modulate its function remains poorly understood. Here, we report that BAP1 forms two mutually exclusive complexes with the transcriptional regulators ASXL1 and ASXL2, which are necessary for maintaining proper protein levels of this DUB. Conversely, BAP1 is essential for maintaining ASXL2, but not ASXL1, protein stability. Notably, cancer-associated loss of BAP1 expression results in ASXL2 destabilization and hence loss of its function. ASXL1 and ASXL2 use their ASXM domains to interact with the C-terminal domain (CTD) of BAP1, and these interactions are required for ubiquitin binding and H2A deubiquitination. The deubiquitination-promoting effect of ASXM requires intramolecular interactions between catalytic and non-catalytic domains of BAP1, which generate a composite ubiquitin-binding interface (CUBI). Notably, the CUBI engages multiple interactions with ubiquitin involving (i) the ubiquitin carboxyl hydrolase catalytic domain of BAP1, which interacts with the hydrophobic patch of ubiquitin, and (ii) the CTD domain, which interacts with a charged patch of ubiquitin. Significantly, we identified cancer-associated mutations of BAP1 that disrupt the CUBI and notably an in-frame deletion in the CTD that inhibits its interaction with ASXL1/2 and DUB activity and deregulates cell proliferation. Moreover, we demonstrated that BAP1 interaction with ASXL2 regulates cell senescence and that ASXL2 cancer-associated mutations disrupt BAP1 DUB activity. Thus, inactivation of the BAP1/ASXL2 axis might contribute to cancer development.
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Affiliation(s)
- Salima Daou
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Ian Hammond-Martel
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Nazar Mashtalir
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Haithem Barbour
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Jessica Gagnon
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Nicholas V G Iannantuono
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Nadine Sen Nkwe
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Alena Motorina
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Helen Pak
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Helen Yu
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Hugo Wurtele
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Eric Milot
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Frédérick A Mallette
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
| | - Michele Carbone
- the Thoracic Oncology Program, University of Hawaii Cancer Center, Honolulu, Hawaii 96813
| | - El Bachir Affar
- From the Maisonneuve-Rosemont Hospital Research Center and Department of Medicine, University of Montréal, Montréal, Québec H3C 3J7, Canada and
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Aufderheide A, Unverdorben P, Baumeister W, Förster F. Structural disorder and its role in proteasomal degradation. FEBS Lett 2015; 589:2552-60. [PMID: 26226424 DOI: 10.1016/j.febslet.2015.07.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 07/17/2015] [Accepted: 07/17/2015] [Indexed: 10/23/2022]
Abstract
The ubiquitin proteasome system is responsible for the controlled degradation of a vast number of intracellular proteins. It targets misfolded or otherwise aberrant proteins as well as proteins no longer needed at a given point in time. The 26S proteasome is a large macromolecular machine comprising 33 distinct subunits as well as a number of transiently associating cofactors. Being essentially a non-specific protease, specificity is conferred by the ubiquitin system, which selects and marks substrates for degradation. Here, we review our current understanding of the structure and function of the 26S proteasome; in doing so we highlight the role of disordered protein regions. Disordered segments in substrates promote their degradation, whereas low complexity regions prevent their proteolysis. In the 26S proteasome itself a main role of disordered segments seems to be rendering the ubiquitin receptors mobile, possibly supporting recruitment of polyubiquitylated substrates. Thus, these structural features of substrates as well as of the 26S proteasome itself likely play important roles at different stages of the protein degradation process.
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Affiliation(s)
- Antje Aufderheide
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Martinsried, Germany
| | - Pia Unverdorben
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Martinsried, Germany
| | - Wolfgang Baumeister
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Martinsried, Germany.
| | - Friedrich Förster
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Martinsried, Germany.
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Cancer-associated ASXL1 mutations may act as gain-of-function mutations of the ASXL1-BAP1 complex. Nat Commun 2015; 6:7307. [PMID: 26095772 PMCID: PMC4557297 DOI: 10.1038/ncomms8307] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 04/27/2015] [Indexed: 12/29/2022] Open
Abstract
ASXL1 is the obligate regulatory subunit of a deubiquitinase complex whose catalytic subunit is BAP1. Heterozygous mutations of ASXL1 that result in premature truncations are frequent in myeloid leukemias and Bohring-Opitz syndrome. Here we demonstrate that ASXL1 truncations confer enhanced activity on the ASXL1-BAP1 complex. Stable expression of truncated, hyperactive ASXL1-BAP1 complexes in a haematopoietic precursor cell line results in global erasure of H2AK119Ub, striking depletion of H3K27me3, selective upregulation of a subset of genes whose promoters are marked by both H2AK119Ub and H3K4me3, and spontaneous differentiation to the mast cell lineage. These outcomes require the catalytic activity of BAP1, indicating that they are downstream consequences of H2AK119Ub erasure. In bone marrow precursors, expression of truncated ASXL1-BAP1 complex cooperates with TET2 loss-of-function to increase differentiation to the myeloid lineage in vivo. Our data raise the possibility that ASXL1 truncation mutations confer gain-of-function on the ASXL-BAP1 complex.
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Sahtoe DD, Sixma TK. Layers of DUB regulation. Trends Biochem Sci 2015; 40:456-67. [PMID: 26073511 DOI: 10.1016/j.tibs.2015.05.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/06/2015] [Accepted: 05/11/2015] [Indexed: 11/15/2022]
Abstract
Proteolytic enzymes, such as (iso-)peptidases, are potentially hazardous for cells. To neutralize their potential danger, tight control of their activities has evolved. Deubiquitylating enzymes (DUBs) are isopeptidases involved in eukaryotic ubiquitylation. They reverse ubiquitin signals by hydrolyzing ubiquitin adducts, giving them control over all aspects of ubiquitin biology. The importance of DUB function is underscored by their frequent deregulation in human disease, making these enzymes potential drug targets. Here, we review the different layers of DUB enzyme regulation. We discuss how post-translational modification (PTM), regulatory domains within DUBs, and incorporation of DUBs into macromolecular complexes contribute to their activity. We conclude that most DUBs are likely to use a combination of these basic regulatory mechanisms.
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Affiliation(s)
- Danny D Sahtoe
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Titia K Sixma
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
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35
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Abstract
Two studies in this issue of Molecular Cell,VanderLinden et al. (2015) and Sahtoe et al. (2015),report crystal structures that define how deubiquitinating enzyme UCH37 is switched on or off by proteasome ubiquitin receptor RPN13 or chromatin remodeler component INO80G.
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36
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The stability of epigenetic factor ASXL1 is regulated through ubiquitination and USP7-mediated deubiquitination. Leukemia 2015; 29:2257-60. [DOI: 10.1038/leu.2015.90] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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37
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Vander Linden RT, Hemmis CW, Schmitt B, Ndoja A, Whitby FG, Robinson H, Cohen RE, Yao T, Hill CP. Structural basis for the activation and inhibition of the UCH37 deubiquitylase. Mol Cell 2015; 57:901-911. [PMID: 25702872 DOI: 10.1016/j.molcel.2015.01.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 12/15/2014] [Accepted: 01/06/2015] [Indexed: 10/24/2022]
Abstract
The UCH37 deubiquitylase functions in two large and very different complexes, the 26S proteasome and the INO80 chromatin remodeler. We have performed biochemical characterization and determined crystal structures of UCH37 in complexes with RPN13 and NFRKB, which mediate its recruitment to the proteasome and INO80, respectively. RPN13 and NFRKB make similar contacts to the UCH37 C-terminal domain but quite different contacts to the catalytic UCH domain. RPN13 can activate UCH37 by disrupting dimerization, although physiologically relevant activation likely results from stabilization of a surface competent for ubiquitin binding and modulation of the active-site crossover loop. In contrast, NFRKB inhibits UCH37 by blocking the ubiquitin-binding site and by disrupting the enzyme active site. These findings reveal remarkable commonality in mechanisms of recruitment, yet very different mechanisms of regulating enzyme activity, and provide a foundation for understanding the roles of UCH37 in the unrelated proteasome and INO80 complexes.
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Affiliation(s)
- Ryan T Vander Linden
- Department of Biochemistry University of Utah School of Medicine, Salt Lake City, UT 84112-5650 USA
| | - Casey W Hemmis
- Department of Biochemistry University of Utah School of Medicine, Salt Lake City, UT 84112-5650 USA
| | - Benjamin Schmitt
- Department of Biochemistry and Molecular Biology Colorado State University, Fort Collins, CO 80523 USA
| | - Ada Ndoja
- Department of Biochemistry and Molecular Biology Colorado State University, Fort Collins, CO 80523 USA
| | - Frank G Whitby
- Department of Biochemistry University of Utah School of Medicine, Salt Lake City, UT 84112-5650 USA
| | - Howard Robinson
- Biology Department Brookhaven National Laboratory, Upton, NY, 11973 USA
| | - Robert E Cohen
- Department of Biochemistry and Molecular Biology Colorado State University, Fort Collins, CO 80523 USA
| | - Tingting Yao
- Department of Biochemistry and Molecular Biology Colorado State University, Fort Collins, CO 80523 USA
| | - Christopher P Hill
- Department of Biochemistry University of Utah School of Medicine, Salt Lake City, UT 84112-5650 USA
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38
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Sahtoe DD, van Dijk WJ, El Oualid F, Ekkebus R, Ovaa H, Sixma TK. Mechanism of UCH-L5 activation and inhibition by DEUBAD domains in RPN13 and INO80G. Mol Cell 2015; 57:887-900. [PMID: 25702870 PMCID: PMC4352763 DOI: 10.1016/j.molcel.2014.12.039] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/16/2014] [Accepted: 12/24/2014] [Indexed: 12/15/2022]
Abstract
Deubiquitinating enzymes (DUBs) control vital processes in eukaryotes by hydrolyzing ubiquitin adducts. Their activities are tightly regulated, but the mechanisms remain elusive. In particular, the DUB UCH-L5 can be either activated or inhibited by conserved regulatory proteins RPN13 and INO80G, respectively. Here we show how the DEUBAD domain in RPN13 activates UCH-L5 by positioning its C-terminal ULD domain and crossover loop to promote substrate binding and catalysis. The related DEUBAD domain in INO80G inhibits UCH-L5 by exploiting similar structural elements in UCH-L5 to promote a radically different conformation, and employs molecular mimicry to block ubiquitin docking. In this process, large conformational changes create small but highly specific interfaces that mediate activity modulation of UCH-L5 by altering the affinity for substrates. Our results establish how related domains can exploit enzyme conformational plasticity to allosterically regulate DUB activity. These allosteric sites may present novel insights for pharmaceutical intervention in DUB activity. The RPN13 DEUBAD domain activates UCH-L5 by positioning its CL and ULD domain The INO80G DEUBAD domain inhibits UCH-L5 by blocking ubiquitin binding The FRF hairpin in the DEUBAD domain of INO80G drives UCH-L5 inhibition DEUBAD domains regulate UCH-L5 activity by tuning UCH-L5 substrate affinity
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Affiliation(s)
- Danny D Sahtoe
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Willem J van Dijk
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Farid El Oualid
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands; UbiQ, Science Park 408, 1098XH Amsterdam, the Netherlands
| | - Reggy Ekkebus
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Huib Ovaa
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Titia K Sixma
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands.
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Sanchez-Pulido L, Ponting CP. TM6SF2 and MAC30, new enzyme homologs in sterol metabolism and common metabolic disease. Front Genet 2014; 5:439. [PMID: 25566323 PMCID: PMC4263179 DOI: 10.3389/fgene.2014.00439] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/27/2014] [Indexed: 12/14/2022] Open
Abstract
Carriers of the Glu167Lys coding variant in the TM6SF2 gene have recently been identified as being more susceptible to non-alcoholic fatty liver disease (NAFLD), yet exhibit lower levels of circulating lipids and hence are protected against cardiovascular disease. Despite the physiological importance of these observations, the molecular function of TM6SF2 remains unknown, and no sequence similarity with functionally characterized proteins has been identified. In order to trace its evolutionary history and to identify functional domains, we embarked on a computational protein sequence analysis of TM6SF2. We identified a new domain, the EXPERA domain, which is conserved among TM6SF, MAC30/TMEM97 and EBP (D8, D7 sterol isomerase) protein families. EBP mutations are the cause of chondrodysplasia punctata 2 X-linked dominant (CDPX2), also known as Conradi-Hünermann-Happle syndrome, a defective cholesterol biosynthesis disorder. Our analysis of evolutionary conservation among EXPERA domain-containing families and the previously suggested catalytic mechanism for the EBP enzyme, indicate that TM6SF and MAC30/TMEM97 families are both highly likely to possess, as for the EBP family, catalytic activity as sterol isomerases. This unexpected prediction of enzymatic functions for TM6SF and MAC30/TMEM97 is important because it now permits detailed experiments to investigate the function of these key proteins in various human pathologies, from cardiovascular disease to cancer.
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Affiliation(s)
- Luis Sanchez-Pulido
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
| | - Chris P Ponting
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
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40
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Pereira RV, Vieira HGS, de Oliveira VF, Gomes MDS, Passos LKJ, Borges WDC, Guerra-Sá R. Conservation and developmental expression of ubiquitin isopeptidases in Schistosoma mansoni. Mem Inst Oswaldo Cruz 2014; 109:1-8. [PMID: 24271000 PMCID: PMC4005531 DOI: 10.1590/0074-0276130107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 09/09/2013] [Indexed: 11/22/2022] Open
Abstract
Several genes related to the ubiquitin (Ub)-proteasome pathway, including those coding for proteasome subunits and conjugation enzymes, are differentially expressed during the Schistosoma mansoni life cycle. Although deubiquitinating enzymes have been reported to be negative regulators of protein ubiquitination and shown to play an important role in Ub-dependent processes, little is known about their role in S. mansoni . In this study, we analysed the Ub carboxyl-terminal hydrolase (UCHs) proteins found in the database of the parasite's genome. An in silico ana- lysis (GeneDB and MEROPS) identified three different UCH family members in the genome, Sm UCH-L3, Sm UCH-L5 and Sm BAP-1 and a phylogenetic analysis confirmed the evolutionary conservation of the proteins. We performed quantitative reverse transcription-polymerase chain reaction and observed a differential expression profile for all of the investigated transcripts between the cercariae and adult worm stages. These results were corroborated by low rates of Z-Arg-Leu-Arg-Gly-Gly-AMC hydrolysis in a crude extract obtained from cercariae in parallel with high Ub conjugate levels in the same extracts. We suggest that the accumulation of ubiquitinated proteins in the cercaria and early schistosomulum stages is related to a decrease in 26S proteasome activity. Taken together, our data suggest that UCH family members contribute to regulating the activity of the Ub-proteasome system during the life cycle of this parasite.
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Affiliation(s)
- Roberta Verciano Pereira
- Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de
Ouro Preto, Ouro Preto, MG, Brasil, Núcleo de Pesquisas em Ciências Biológicas,
Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil
| | - Helaine Graziele Santos Vieira
- Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de
Ouro Preto, Ouro Preto, MG, Brasil, Núcleo de Pesquisas em Ciências Biológicas,
Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil
| | - Victor Fernandes de Oliveira
- Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de
Ouro Preto, Ouro Preto, MG, Brasil, Núcleo de Pesquisas em Ciências Biológicas,
Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil
| | - Matheus de Souza Gomes
- Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia,
Patos de Minas, MG, Brasil, Instituto de Genética e Bioquímica, Universidade Federal de
Uberlândia, Campus Avançado Patos de Minas, MG, Brasil
| | | | - William de Castro Borges
- Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de
Ouro Preto, Ouro Preto, MG, Brasil, Núcleo de Pesquisas em Ciências Biológicas,
Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil
| | - Renata Guerra-Sá
- Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de
Ouro Preto, Ouro Preto, MG, Brasil, Núcleo de Pesquisas em Ciências Biológicas,
Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil
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41
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Functional and cancer genomics of ASXL family members. Br J Cancer 2013; 109:299-306. [PMID: 23736028 PMCID: PMC3721406 DOI: 10.1038/bjc.2013.281] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 05/08/2013] [Accepted: 05/10/2013] [Indexed: 12/22/2022] Open
Abstract
Additional sex combs-like (ASXL)1, ASXL2 and ASXL3 are human homologues of the Drosophila Asx gene that are involved in the regulation or recruitment of the Polycomb-group repressor complex (PRC) and trithorax-group (trxG) activator complex. ASXL proteins consist of ASXN, ASXH, ASXM1, ASXM2 and PHD domains. ASXL1 directly interacts with BAP1, KDM1A (LSD1), NCOA1 and nuclear hormone receptors (NHRs), such as retinoic acid receptors, oestrogen receptor and androgen receptor. ASXL family members are epigenetic scaffolding proteins that assemble epigenetic regulators and transcription factors to specific genomic loci with histone modifications. ASXL1 is involved in transcriptional repression through an interaction with PRC2 and also contributes to transcriptional regulation through interactions with BAP1 and/or NHR complexes. Germ-line mutations of human ASXL1 and ASXL3 occur in Bohring-Opitz and related syndromes. Amplification and overexpression of ASXL1 occur in cervical cancer. Truncation mutations of ASXL1 occur in colorectal cancers with microsatellite instability (MSI), malignant myeloid diseases, chronic lymphocytic leukaemia, head and neck squamous cell carcinoma, and liver, prostate and breast cancers; those of ASXL2 occur in prostate cancer, pancreatic cancer and breast cancer and those of ASXL3 are observed in melanoma. EPC1-ASXL2 gene fusion occurs in adult T-cell leukaemia/lymphoma. The prognosis of myeloid malignancies with misregulating truncation mutations of ASXL1 is poor. ASXL family members are assumed to be tumour suppressive or oncogenic in a context-dependent manner.
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Morrow ME, Kim MI, Ronau JA, Sheedlo MJ, White RR, Chaney J, Paul LN, Lill MA, Artavanis-Tsakonas K, Das C. Stabilization of an unusual salt bridge in ubiquitin by the extra C-terminal domain of the proteasome-associated deubiquitinase UCH37 as a mechanism of its exo specificity. Biochemistry 2013; 52:3564-78. [PMID: 23617878 PMCID: PMC3898853 DOI: 10.1021/bi4003106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ubiquitination is countered by a group of enzymes collectively called deubiquitinases (DUBs); ∼100 of them can be found in the human genome. One of the most interesting aspects of these enzymes is the ability of some members to selectively recognize specific linkage types between ubiquitin in polyubiquitin chains and their endo and exo specificity. The structural basis of exo-specific deubiquitination catalyzed by a DUB is poorly understood. UCH37, a cysteine DUB conserved from fungi to humans, is a proteasome-associated factor that regulates the proteasome by sequentially cleaving polyubiquitin chains from their distal ends, i.e., by exo-specific deubiquitination. In addition to the catalytic domain, the DUB features a functionally uncharacterized UCH37-like domain (ULD), presumed to keep the enzyme in an inhibited state in its proteasome-free form. Herein we report the crystal structure of two constructs of UCH37 from Trichinella spiralis in complex with a ubiquitin-based suicide inhibitor, ubiquitin vinyl methyl ester (UbVME). These structures show that the ULD makes direct contact with ubiquitin stabilizing a highly unusual intramolecular salt bridge between Lys48 and Glu51 of ubiquitin, an interaction that would be favored only with the distal ubiquitin but not with the internal ones in a Lys48-linked polyubiquitin chain. An inspection of 39 DUB-ubiquitin structures in the Protein Data Bank reveals the uniqueness of the salt bridge in ubiquitin bound to UCH37, an interaction that disappears when the ULD is deleted, as revealed in the structure of the catalytic domain alone bound to UbVME. The structural data are consistent with previously reported mutational data on the mammalian enzyme, which, together with the fact that the ULD residues that bind to ubiquitin are conserved, points to a similar mechanism behind the exo specificity of the human enzyme. To the best of our knowledge, these data provide the only structural example so far of how the exo specificity of a DUB can be determined by its noncatalytic domain. Thus, our data show that, contrary to its proposed inhibitory role, the ULD actually contributes to substrate recognition and could be a major determinant of the proteasome-associated function of UCH37. Moreover, our structures show that the unproductively oriented catalytic cysteine in the free enzyme is aligned correctly when ubiquitin binds, suggesting a mechanism for ubiquitin selectivity.
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Affiliation(s)
- Marie E. Morrow
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Myung-Il Kim
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Judith A. Ronau
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Michael J. Sheedlo
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Rhiannon R. White
- Division of Cell and Molecular Biology, Imperial College London, Sir Alexander Fleming Bldg, Imperial College Road, London, SW7 2AZ, UK
| | - Joseph Chaney
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Lake N. Paul
- Bindley Biosciences Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Markus A. Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA
| | - Katerina Artavanis-Tsakonas
- Division of Cell and Molecular Biology, Imperial College London, Sir Alexander Fleming Bldg, Imperial College Road, London, SW7 2AZ, UK
| | - Chittaranjan Das
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA,To whom correspondence should be addressed: Chittaranjan Das, Brown Laboratory of Chemistry, 560 Oval Drive, West Lafayette, IN, 47907, (765)-494-5478, Fax: (765)-494-0239,
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43
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Lopez-Castejon G, Luheshi NM, Compan V, High S, Whitehead RC, Flitsch S, Kirov A, Prudovsky I, Swanton E, Brough D. Deubiquitinases regulate the activity of caspase-1 and interleukin-1β secretion via assembly of the inflammasome. J Biol Chem 2012; 288:2721-33. [PMID: 23209292 PMCID: PMC3554938 DOI: 10.1074/jbc.m112.422238] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
IL-1β is a potent pro-inflammatory cytokine produced in response to infection or injury. It is synthesized as an inactive precursor that is activated by the protease caspase-1 within a cytosolic molecular complex called the inflammasome. Assembly of this complex is triggered by a range of structurally diverse damage or pathogen associated stimuli, and the signaling pathways through which these act are poorly understood. Ubiquitination is a post-translational modification essential for maintaining cellular homeostasis. It can be reversed by deubiquitinase enzymes (DUBs) that remove ubiquitin moieties from the protein thus modifying its fate. DUBs present specificity toward different ubiquitin chain topologies and are crucial for recycling ubiquitin molecules before protein degradation as well as regulating key cellular processes such as protein trafficking, gene transcription, and signaling. We report here that small molecule inhibitors of DUB activity inhibit inflammasome activation. Inhibition of DUBs blocked the processing and release of IL-1β in both mouse and human macrophages. DUB activity was necessary for inflammasome association as DUB inhibition also impaired ASC oligomerization and caspase-1 activation without directly blocking caspase-1 activity. These data reveal the requirement for DUB activity in a key reaction of the innate immune response and highlight the therapeutic potential of DUB inhibitors for chronic auto-inflammatory diseases.
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Affiliation(s)
- Gloria Lopez-Castejon
- AV Hill Building, Faculty of Life Sciences, University of Manchester Manchester, M13 9PT, United Kingdom
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