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Nashabat M, Nabavizadeh N, Saraçoğlu HP, Sarıbaş B, Avcı Ş, Börklü E, Beillard E, Yılmaz E, Uygur SE, Kayhan CK, Bosco L, Eren ZB, Steindl K, Richter MF, Bademci G, Rauch A, Fattahi Z, Valentino ML, Connolly AM, Bahr A, Viola L, Bergmann AK, Rocha ME, Peart L, Castro-Rojas DL, Bültmann E, Khan S, Giarrana ML, Teleanu RI, Gonzalez JM, Pini A, Schädlich IS, Vill K, Brugger M, Zuchner S, Pinto A, Donkervoort S, Bivona SA, Riza A, Streata I, Gläser D, Baquero-Montoya C, Garcia-Restrepo N, Kotzaeridou U, Brunet T, Epure DA, Bertoli-Avella A, Kariminejad A, Tekin M, von Hardenberg S, Bönnemann CG, Stettner GM, Zanni G, Kayserili H, Oflazer ZP, Escande-Beillard N. SNUPN deficiency causes a recessive muscular dystrophy due to RNA mis-splicing and ECM dysregulation. Nat Commun 2024; 15:1758. [PMID: 38413582 PMCID: PMC10899626 DOI: 10.1038/s41467-024-45933-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 02/08/2024] [Indexed: 02/29/2024] Open
Abstract
SNURPORTIN-1, encoded by SNUPN, plays a central role in the nuclear import of spliceosomal small nuclear ribonucleoproteins. However, its physiological function remains unexplored. In this study, we investigate 18 children from 15 unrelated families who present with atypical muscular dystrophy and neurological defects. Nine hypomorphic SNUPN biallelic variants, predominantly clustered in the last coding exon, are ascertained to segregate with the disease. We demonstrate that mutant SPN1 failed to oligomerize leading to cytoplasmic aggregation in patients' primary fibroblasts and CRISPR/Cas9-mediated mutant cell lines. Additionally, mutant nuclei exhibit defective spliceosomal maturation and breakdown of Cajal bodies. Transcriptome analyses reveal splicing and mRNA expression dysregulation, particularly in sarcolemmal components, causing disruption of cytoskeletal organization in mutant cells and patient muscle tissues. Our findings establish SNUPN deficiency as the genetic etiology of a previously unrecognized subtype of muscular dystrophy and provide robust evidence of the role of SPN1 for muscle homeostasis.
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Affiliation(s)
- Marwan Nashabat
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Nasrinsadat Nabavizadeh
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Hilal Pırıl Saraçoğlu
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Burak Sarıbaş
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Şahin Avcı
- Diagnostic Center for Genetic Diseases, Department of Medical Genetics, Koç University Hospital, Istanbul, Turkey
| | - Esra Börklü
- Diagnostic Center for Genetic Diseases, Department of Medical Genetics, Koç University Hospital, Istanbul, Turkey
| | | | - Elanur Yılmaz
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Seyide Ecesu Uygur
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Cavit Kerem Kayhan
- Pathology Laboratory, Acıbadem Maslak Hospital, Istanbul, Turkey
- Department of Biotechnology, Nişantaşı University, Istanbul, Turkey
| | - Luca Bosco
- Unit of Muscular and Neurodegenerative Disorders and Developmental Neurology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
- Department of Science, University "Roma Tre", Rome, Italy
| | - Zeynep Bengi Eren
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | | | - Guney Bademci
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
- Research Priority Program (URPP) ITINERARE: Innovative Therapies in Rare Diseases, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Zohreh Fattahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Kariminejad-Najmabadi Pathology & Genetics Centre, Tehran, Iran
| | - Maria Lucia Valentino
- IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Anne M Connolly
- Division of Neurology, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Angela Bahr
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Laura Viola
- Unit of Clinical Pediatrics, State Hospital, San Marino Republic, Italy
| | | | | | - LeShon Peart
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Derly Liseth Castro-Rojas
- Genomics Laboratory, Center of Immunology and Genetics (CIGE), SURA Ayudas Diagnosticas, Medellín, Colombia
| | - Eva Bültmann
- Institute of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany
| | | | | | - Raluca Ioana Teleanu
- Dr Victor Gomoiu Children's Hospital, Bucharest, Romania
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Joanna Michelle Gonzalez
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Antonella Pini
- Neuromuscular Pediatric Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
| | - Ines Sophie Schädlich
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg-Eppendorf, Germany
| | - Katharina Vill
- Department of Pediatric Neurology and Developmental Medicine and LMU Center for Children with Medical Complexity, Dr. von Hauner Children's Hospital, LMU Hospital, Ludwig-Maximilians-University, Munich, Germany
- Department of Human Genetics, Technical University of Munich, School of Medicine, Munich, Germany
| | - Melanie Brugger
- Department of Human Genetics, Technical University of Munich, School of Medicine, Munich, Germany
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
- John P. Hussmann Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Stephanie Ann Bivona
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Anca Riza
- Human Genomics Laboratory, University of Medicine and Pharmacy, Craiova, Romania
- Regional Centre of Medical Genetics Dolj, County Clinical Emergency Hospital, Craiova, Romania
| | - Ioana Streata
- Human Genomics Laboratory, University of Medicine and Pharmacy, Craiova, Romania
- Regional Centre of Medical Genetics Dolj, County Clinical Emergency Hospital, Craiova, Romania
| | | | | | | | - Urania Kotzaeridou
- Division of Child Neurology and Inherited Metabolic Diseases, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Theresa Brunet
- Department of Pediatric Neurology and Developmental Medicine and LMU Center for Children with Medical Complexity, Dr. von Hauner Children's Hospital, LMU Hospital, Ludwig-Maximilians-University, Munich, Germany
- Department of Human Genetics, Technical University of Munich, School of Medicine, Munich, Germany
| | | | | | | | - Mustafa Tekin
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
- John P. Hussmann Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Georg M Stettner
- Neuromuscular Center Zurich and Department of Pediatric Neurology, University Children's Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Ginevra Zanni
- Unit of Muscular and Neurodegenerative Disorders and Developmental Neurology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Hülya Kayserili
- Diagnostic Center for Genetic Diseases, Department of Medical Genetics, Koç University Hospital, Istanbul, Turkey
- Department of Medical Genetics, Koç University School of Medicine (KUSoM), Istanbul, Turkey
| | - Zehra Piraye Oflazer
- Department of Neurology, Koç University Hospital Muscle Center, Istanbul, Turkey
| | - Nathalie Escande-Beillard
- Laboratory of Functional Genomics, Department of Medical Genetics, Koç University, School of Medicine (KUSoM), Istanbul, Turkey.
- Research Center for Translational Medicine (KUTTAM), Koç University School of Medicine (KUSoM), Istanbul, Turkey.
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Yang Y, Guo L, Chen L, Gong B, Jia D, Sun Q. Nuclear transport proteins: structure, function, and disease relevance. Signal Transduct Target Ther 2023; 8:425. [PMID: 37945593 PMCID: PMC10636164 DOI: 10.1038/s41392-023-01649-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 11/12/2023] Open
Abstract
Proper subcellular localization is crucial for the functioning of biomacromolecules, including proteins and RNAs. Nuclear transport is a fundamental cellular process that regulates the localization of many macromolecules within the nuclear or cytoplasmic compartments. In humans, approximately 60 proteins are involved in nuclear transport, including nucleoporins that form membrane-embedded nuclear pore complexes, karyopherins that transport cargoes through these complexes, and Ran system proteins that ensure directed and rapid transport. Many of these nuclear transport proteins play additional and essential roles in mitosis, biomolecular condensation, and gene transcription. Dysregulation of nuclear transport is linked to major human diseases such as cancer, neurodegenerative diseases, and viral infections. Selinexor (KPT-330), an inhibitor targeting the nuclear export factor XPO1 (also known as CRM1), was approved in 2019 to treat two types of blood cancers, and dozens of clinical trials of are ongoing. This review summarizes approximately three decades of research data in this field but focuses on the structure and function of individual nuclear transport proteins from recent studies, providing a cutting-edge and holistic view on the role of nuclear transport proteins in health and disease. In-depth knowledge of this rapidly evolving field has the potential to bring new insights into fundamental biology, pathogenic mechanisms, and therapeutic approaches.
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Affiliation(s)
- Yang Yang
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lu Guo
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lin Chen
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Gong
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China.
| | - Qingxiang Sun
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu, China.
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Jafarinia H, Van der Giessen E, Onck PR. Molecular basis of C9orf72 poly-PR interference with the β-karyopherin family of nuclear transport receptors. Sci Rep 2022; 12:21324. [PMID: 36494425 PMCID: PMC9734553 DOI: 10.1038/s41598-022-25732-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Nucleocytoplasmic transport (NCT) is affected in several neurodegenerative diseases including C9orf72-ALS. It has recently been found that arginine-containing dipeptide repeat proteins (R-DPRs), translated from C9orf72 repeat expansions, directly bind to several importins. To gain insight into how this can affect nucleocytoplasmic transport, we use coarse-grained molecular dynamics simulations to study the molecular interaction of poly-PR, the most toxic DPR, with several Kapβs (importins and exportins). We show that poly-PR-Kapβ binding depends on the net charge per residue (NCPR) of the Kapβ, salt concentration of the solvent, and poly-PR length. Poly-PR makes contact with the inner surface of most importins, which strongly interferes with Kapβ binding to cargo-NLS, IBB, and RanGTP in a poly-PR length-dependent manner. Longer poly-PRs at higher concentrations are also able to make contact with the outer surface of importins that contain several binding sites to FG-Nups. We also show that poly-PR binds to exportins, especially at lower salt concentrations, interacting with several RanGTP and FG-Nup binding sites. Overall, our results suggest that poly-PR might cause length-dependent defects in cargo loading, cargo release, Kapβ transport and Ran gradient across the nuclear envelope.
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Affiliation(s)
- Hamidreza Jafarinia
- grid.4830.f0000 0004 0407 1981Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Erik Van der Giessen
- grid.4830.f0000 0004 0407 1981Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Patrick R. Onck
- grid.4830.f0000 0004 0407 1981Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
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4
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Mattola S, Aho V, Bustamante‐Jaramillo LF, Pizzioli E, Kann M, Vihinen‐Ranta M. Nuclear entry and egress of parvoviruses. Mol Microbiol 2022; 118:295-308. [PMID: 35974704 PMCID: PMC9805091 DOI: 10.1111/mmi.14974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/10/2022] [Accepted: 08/13/2022] [Indexed: 01/09/2023]
Abstract
Parvoviruses are small non-enveloped single-stranded DNA viruses, which depend on host cell nuclear transcriptional and replication machinery. After endosomal exposure of nuclear localization sequence and a phospholipase A2 domain on the capsid surface, and escape into the cytosol, parvovirus capsids enter the nucleus. Due to the small capsid diameter of 18-26 nm, intact capsids can potentially pass into the nucleus through nuclear pore complexes (NPCs). This might be facilitated by active nuclear import, but capsids may also follow an alternative entry pathway that includes activation of mitotic factors and local transient disruption of the nuclear envelope. The nuclear entry is followed by currently undefined events of viral genome uncoating. After genome release, viral replication compartments are initiated and infection proceeds. Parvoviral genomes replicate during cellular S phase followed by nuclear capsid assembly during virus-induced S/G2 cell cycle arrest. Nuclear egress of capsids occurs upon nuclear envelope degradation during apoptosis and cell lysis. An alternative pathway for nuclear export has been described using active transport through the NPC mediated by the chromosome region maintenance 1 protein, CRM1, which is enhanced by phosphorylation of the N-terminal domain of VP2. However, other alternative but not yet uncharacterized nuclear export pathways cannot be excluded.
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Affiliation(s)
- Salla Mattola
- Department of Biological and Environmental ScienceUniversity of JyvaskylaJyvaskylaFinland
| | - Vesa Aho
- Department of Biological and Environmental ScienceUniversity of JyvaskylaJyvaskylaFinland
| | | | - Edoardo Pizzioli
- Department of Infectious Diseases, Institute of BiomedicineUniversity of GothenburgGothenburgSweden
| | - Michael Kann
- Department of Infectious Diseases, Institute of BiomedicineUniversity of GothenburgGothenburgSweden,Sahlgrenska AcademyGothenburgSweden,Department of Clinical MicrobiologyRegion Västra Götaland, Sahlgrenska University HospitalGothenburgSweden
| | - Maija Vihinen‐Ranta
- Department of Biological and Environmental ScienceUniversity of JyvaskylaJyvaskylaFinland
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Spittler D, Indorato RL, Boeri Erba E, Delaforge E, Signor L, Harris SJ, Garcia-Saez I, Palencia A, Gabel F, Blackledge M, Noirclerc-Savoye M, Petosa C. Binding stoichiometry and structural model of the HIV-1 Rev/importin β complex. Life Sci Alliance 2022; 5:5/10/e202201431. [PMID: 35995566 PMCID: PMC9396022 DOI: 10.26508/lsa.202201431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/24/2022] Open
Abstract
HIV-1 Rev mediates the nuclear export of intron-containing viral RNA transcripts and is essential for viral replication. Rev is imported into the nucleus by the host protein importin β (Impβ), but how Rev associates with Impβ is poorly understood. Here, we report biochemical, mutational, and biophysical studies of the Impβ/Rev complex. We show that Impβ binds two Rev monomers through independent binding sites, in contrast to the 1:1 binding stoichiometry observed for most Impβ cargos. Peptide scanning data and charge-reversal mutations identify the N-terminal tip of Rev helix α2 within Rev's arginine-rich motif (ARM) as a primary Impβ-binding epitope. Cross-linking mass spectrometry and compensatory mutagenesis data combined with molecular docking simulations suggest a structural model in which one Rev monomer binds to the C-terminal half of Impβ with Rev helix α2 roughly parallel to the HEAT-repeat superhelical axis, whereas the other monomer binds to the N-terminal half. These findings shed light on the molecular basis of Rev recognition by Impβ and highlight an atypical binding behavior that distinguishes Rev from canonical cellular Impβ cargos.
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Affiliation(s)
- Didier Spittler
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Rose-Laure Indorato
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Elisabetta Boeri Erba
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Elise Delaforge
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Luca Signor
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Simon J Harris
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Isabel Garcia-Saez
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Andrés Palencia
- Institute for Advanced Biosciences, Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Frank Gabel
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Martin Blackledge
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Marjolaine Noirclerc-Savoye
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
| | - Carlo Petosa
- Université Grenoble Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale, Grenoble, France
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Huang JL, Yan XL, Li W, Fan RZ, Li S, Chen J, Zhang Z, Sang J, Gan L, Tang GH, Chen H, Wang J, Yin S. Discovery of Highly Potent Daphnane Diterpenoids Uncovers Importin-β1 as a Druggable Vulnerability in Castration-Resistant Prostate Cancer. J Am Chem Soc 2022; 144:17522-17532. [DOI: 10.1021/jacs.2c06449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jia-Luo Huang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Xue-Long Yan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
- School of Pharmacy, Guizhou Medical University, Guian New District, Guizhou 550025, P.R. China
| | - Wei Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Run-Zhu Fan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Shen Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Jianghe Chen
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Zhenhua Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Jun Sang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Lu Gan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Gui-Hua Tang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Hongwu Chen
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, California 95817, United States
| | - Junjian Wang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
- National-Local Joint Engineering Laboratory of Druggability and New Drugs Evaluation, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
| | - Sheng Yin
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, P.R. China
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Boris-Lawrie K, Singh G, Osmer PS, Zucko D, Staller S, Heng X. Anomalous HIV-1 RNA, How Cap-Methylation Segregates Viral Transcripts by Form and Function. Viruses 2022; 14:935. [PMID: 35632676 PMCID: PMC9145092 DOI: 10.3390/v14050935] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/25/2022] [Accepted: 04/25/2022] [Indexed: 12/11/2022] Open
Abstract
The acquisition of m7G-cap-binding proteins is now recognized as a major variable driving the form and function of host RNAs. This manuscript compares the 5'-cap-RNA binding proteins that engage HIV-1 precursor RNAs, host mRNAs, small nuclear (sn)- and small nucleolar (sno) RNAs and sort into disparate RNA-fate pathways. Before completion of the transcription cycle, the transcription start site of nascent class II RNAs is appended to a non-templated guanosine that is methylated (m7G-cap) and bound by hetero-dimeric CBP80-CBP20 cap binding complex (CBC). The CBC is a nexus for the co-transcriptional processing of precursor RNAs to mRNAs and the snRNA and snoRNA of spliceosomal and ribosomal ribonucleoproteins (RNPs). Just as sn/sno-RNAs experience hyper-methylation of m7G-cap to trimethylguanosine (TMG)-cap, so do select HIV RNAs and an emerging cohort of mRNAs. TMG-cap is blocked from Watson:Crick base pairing and disqualified from participating in secondary structure. The HIV TMG-cap has been shown to license select viral transcripts for specialized cap-dependent translation initiation without eIF4E that is dependent upon CBP80/NCBP3. The exceptional activity of HIV precursor RNAs secures their access to maturation pathways of sn/snoRNAs, canonical and non-canonical host mRNAs in proper stoichiometry to execute the retroviral replication cycle.
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Affiliation(s)
- Kathleen Boris-Lawrie
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA; (G.S.); (D.Z.)
| | - Gatikrushna Singh
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA; (G.S.); (D.Z.)
- Department of Neurosurgery, University of Minnesota, Minneapolis, MN 55455, USA
| | - Patrick S. Osmer
- Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA;
| | - Dora Zucko
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA; (G.S.); (D.Z.)
| | - Seth Staller
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA;
| | - Xiao Heng
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA;
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8
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Wonkam A, Adadey SM, Schrauwen I, Aboagye ET, Wonkam-Tingang E, Esoh K, Popel K, Manyisa N, Jonas M, deKock C, Nembaware V, Cornejo Sanchez DM, Bharadwaj T, Nasir A, Everard JL, Kadlubowska MK, Nouel-Saied LM, Acharya A, Quaye O, Amedofu GK, Awandare GA, Leal SM. Exome sequencing of families from Ghana reveals known and candidate hearing impairment genes. Commun Biol 2022; 5:369. [PMID: 35440622 PMCID: PMC9019055 DOI: 10.1038/s42003-022-03326-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/25/2022] [Indexed: 12/15/2022] Open
Abstract
We investigated hearing impairment (HI) in 51 families from Ghana with at least two affected members that were negative for GJB2 pathogenic variants. DNA samples from 184 family members underwent whole-exome sequencing (WES). Variants were found in 14 known non-syndromic HI (NSHI) genes [26/51 (51.0%) families], five genes that can underlie either syndromic HI or NSHI [13/51 (25.5%)], and one syndromic HI gene [1/51 (2.0%)]. Variants in CDH23 and MYO15A contributed the most to HI [31.4% (16/51 families)]. For DSPP, an autosomal recessive mode of inheritance was detected. Post-lingual expression was observed for a family segregating a MARVELD2 variant. To our knowledge, seven novel candidate HI genes were identified (13.7%), with six associated with NSHI (INPP4B, CCDC141, MYO19, DNAH11, POTEI, and SOX9); and one (PAX8) with Waardenburg syndrome. MYO19 and DNAH11 were replicated in unrelated Ghanaian probands. Six of the novel genes were expressed in mouse inner ear. It is known that Pax8-/- mice do not respond to sound, and depletion of Sox9 resulted in defective vestibular structures and abnormal utricle development. Most variants (48/60; 80.0%) have not previously been associated with HI. Identifying seven candidate genes in this study emphasizes the potential of novel HI genes discovery in Africa.
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Affiliation(s)
- Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa.
- McKusick-Nathans Institute and Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Samuel Mawuli Adadey
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Elvis Twumasi Aboagye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Edmond Wonkam-Tingang
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Kevin Esoh
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Kalinka Popel
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Noluthando Manyisa
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Mario Jonas
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Carmen deKock
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Victoria Nembaware
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Diana M Cornejo Sanchez
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Thashi Bharadwaj
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Abdul Nasir
- Department of Molecular Science and Technology, Ajou University, Suwon-si, Republic of Korea
| | - Jenna L Everard
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Magda K Kadlubowska
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Liz M Nouel-Saied
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Anushree Acharya
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Geoffrey K Amedofu
- Department of Eye, Ear, Nose, and Throat, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA.
- Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Centre, New York, NY, 10032, USA.
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9
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Florio TJ, Lokareddy RK, Yeggoni DP, Sankhala RS, Ott CA, Gillilan RE, Cingolani G. Differential recognition of canonical NF-κB dimers by Importin α3. Nat Commun 2022; 13:1207. [PMID: 35260573 PMCID: PMC8904830 DOI: 10.1038/s41467-022-28846-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 02/11/2022] [Indexed: 11/09/2022] Open
Abstract
Nuclear translocation of the p50/p65 heterodimer is essential for NF-κB signaling. In unstimulated cells, p50/p65 is retained by the inhibitor IκBα in the cytoplasm that masks the p65-nuclear localization sequence (NLS). Upon activation, p50/p65 is translocated into the nucleus by the adapter importin α3 and the receptor importin β. Here, we describe a bipartite NLS in p50/p65, analogous to nucleoplasmin NLS but exposed in trans. Importin α3 accommodates the p50- and p65-NLSs at the major and minor NLS-binding pockets, respectively. The p50-NLS is the predominant binding determinant, while the p65-NLS induces a conformational change in the Armadillo 7 of importin α3 that stabilizes a helical conformation of the p65-NLS. Neither conformational change was observed for importin α1, which makes fewer bonds with the p50/p65 NLSs, explaining the preference for α3. We propose that importin α3 discriminates between the transcriptionally active p50/p65 heterodimer and p50/p50 and p65/65 homodimers, ensuring fidelity in NF-κB signaling. Nuclear translocation of the p50/p65 heterodimer is essential for NF-κB signaling. Here, the authors identify a bipartite Nuclear Localization Signal in the NF-κB p50/p65 heterodimer that is recognized with high affinity by importin α3.
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Affiliation(s)
- Tyler J Florio
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Daniel P Yeggoni
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Rajeshwer S Sankhala
- Center of Infectious Disease Research, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Connor A Ott
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY, 14853, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA.
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10
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Akey CW, Singh D, Ouch C, Echeverria I, Nudelman I, Varberg JM, Yu Z, Fang F, Shi Y, Wang J, Salzberg D, Song K, Xu C, Gumbart JC, Suslov S, Unruh J, Jaspersen SL, Chait BT, Sali A, Fernandez-Martinez J, Ludtke SJ, Villa E, Rout MP. Comprehensive structure and functional adaptations of the yeast nuclear pore complex. Cell 2022; 185:361-378.e25. [PMID: 34982960 PMCID: PMC8928745 DOI: 10.1016/j.cell.2021.12.015] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/26/2021] [Accepted: 12/13/2021] [Indexed: 02/06/2023]
Abstract
Nuclear pore complexes (NPCs) mediate the nucleocytoplasmic transport of macromolecules. Here we provide a structure of the isolated yeast NPC in which the inner ring is resolved by cryo-EM at sub-nanometer resolution to show how flexible connectors tie together different structural and functional layers. These connectors may be targets for phosphorylation and regulated disassembly in cells with an open mitosis. Moreover, some nucleoporin pairs and transport factors have similar interaction motifs, which suggests an evolutionary and mechanistic link between assembly and transport. We provide evidence for three major NPC variants that may foreshadow functional specializations at the nuclear periphery. Cryo-electron tomography extended these studies, providing a model of the in situ NPC with a radially expanded inner ring. Our comprehensive model reveals features of the nuclear basket and central transporter, suggests a role for the lumenal Pom152 ring in restricting dilation, and highlights structural plasticity that may be required for transport.
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Affiliation(s)
- Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| | - Digvijay Singh
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Christna Ouch
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Ignacia Echeverria
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, San Francisco, San Francisco, CA 94158, USA
| | - Ilona Nudelman
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA
| | | | - Zulin Yu
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Fei Fang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Junjie Wang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Daniel Salzberg
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Kangkang Song
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Chen Xu
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Sergey Suslov
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jay Unruh
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | | | - Steven J Ludtke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas 77030, USA.
| | - Elizabeth Villa
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA.
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11
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Wing CE, Fung HYJ, Chook YM. Karyopherin-mediated nucleocytoplasmic transport. Nat Rev Mol Cell Biol 2022; 23:307-328. [PMID: 35058649 PMCID: PMC10101760 DOI: 10.1038/s41580-021-00446-7] [Citation(s) in RCA: 107] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2021] [Indexed: 12/25/2022]
Abstract
Efficient and regulated nucleocytoplasmic trafficking of macromolecules to the correct subcellular compartment is critical for proper functions of the eukaryotic cell. The majority of the macromolecular traffic across the nuclear pores is mediated by the Karyopherin-β (or Kap) family of nuclear transport receptors. Work over more than two decades has shed considerable light on how the different Kap family members bring their respective cargoes into the nucleus or the cytoplasm in efficient and highly regulated manners. In this Review, we overview the main features and established functions of Kap family members, describe how Kaps recognize their cargoes and discuss the different ways in which these Kap-cargo interactions can be regulated, highlighting new findings and open questions. We also describe current knowledge of the import and export of the components of three large gene expression machines - the core replisome, RNA polymerase II and the ribosome - pointing out the questions that persist about how such large macromolecular complexes are trafficked to serve their function in a designated subcellular location.
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12
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González-Paz L, Hurtado-León ML, Lossada C, Fernández-Materán FV, Vera-Villalobos J, Loroño M, Paz JL, Jeffreys L, Alvarado YJ. Structural deformability induced in proteins of potential interest associated with COVID-19 by binding of homologues present in ivermectin: Comparative study based in elastic networks models. J Mol Liq 2021; 340:117284. [PMID: 34421159 PMCID: PMC8367659 DOI: 10.1016/j.molliq.2021.117284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 12/24/2022]
Abstract
The COVID-19 pandemic has accelerated the study of the potential of multi-target drugs (MTDs). The mixture of homologues called ivermectin (avermectin-B1a + avermectin-B1b) has been shown to be a MTD with potential antiviral activity against SARS-CoV-2 in vitro. However, there are few reports on the effect of each homologue on the flexibility and stiffness of proteins associated with COVID-19, described as ivermectin targets. We observed that each homologue was stably bound to the proteins studied and was able to induce detectable changes with Elastic Network Models (ENM). The perturbations induced by each homologue were characteristic of each compound and, in turn, were represented by a disruption of native intramolecular networks (interactions between residues). The homologues were able to slightly modify the conformation and stability of the connection points between the Cα atoms of the residues that make up the structural network of proteins (nodes), compared to free proteins. Each homologue was able to modified differently the distribution of quasi-rigid regions of the proteins, which could theoretically alter their biological activities. These results could provide a biophysical-computational view of the potential MTD mechanism that has been reported for ivermectin.
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Affiliation(s)
- Lenin González-Paz
- Universidad del Zulia (LUZ), Facultad Experimental de Ciencias (FEC), Departamento de Biología. Laboratorio de Genética y Biología Molecular (LGBM), 4001 Maracaibo, Republica Bolivariana de Venezuela.,Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Estudios Botánicos y Agroforestales (CEBA), Laboratorio de Protección Vegetal (LPV), 4001 Maracaibo, Republica Bolivariana de Venezuela
| | - María Laura Hurtado-León
- Universidad del Zulia (LUZ), Facultad Experimental de Ciencias (FEC), Departamento de Biología. Laboratorio de Genética y Biología Molecular (LGBM), 4001 Maracaibo, Republica Bolivariana de Venezuela
| | - Carla Lossada
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Investigación y Tecnología de Materiales (CITeMA), Laboratorio de Caracterización Molecular y Biomolecular, 4001 Maracaibo, Republica Bolivariana de Venezuela
| | - Francelys V Fernández-Materán
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Investigación y Tecnología de Materiales (CITeMA), Laboratorio de Caracterización Molecular y Biomolecular, 4001 Maracaibo, Republica Bolivariana de Venezuela
| | - Joan Vera-Villalobos
- Facultad de Ciencias Naturales y Matemáticas, Departamento de Química y Ciencias Ambientales, Laboratorio de Análisis Químico Instrumental (LAQUINS), Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
| | - Marcos Loroño
- Departamento Académico de Química Analítica e Instrumental, Facultad de Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - J L Paz
- Departamento Académico de Química Inorgánica, Facultad de Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Laura Jeffreys
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Ysaias J Alvarado
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Investigación y Tecnología de Materiales (CITeMA), Laboratorio de Caracterización Molecular y Biomolecular, 4001 Maracaibo, Republica Bolivariana de Venezuela
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13
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Kimura M, Imai K, Morinaka Y, Hosono-Sakuma Y, Horton P, Imamoto N. Distinct mutations in importin-β family nucleocytoplasmic transport receptors transportin-SR and importin-13 affect specific cargo binding. Sci Rep 2021; 11:15649. [PMID: 34341383 PMCID: PMC8329185 DOI: 10.1038/s41598-021-94948-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 07/20/2021] [Indexed: 01/25/2023] Open
Abstract
Importin-(Imp)β family nucleocytoplasmic transport receptors (NTRs) are supposed to bind to their cargoes through interaction between a confined interface on an NTR and a nuclear localization or export signal (NLS/NES) on a cargo. Although consensus NLS/NES sequence motifs have been defined for cargoes of some NTRs, many experimentally identified cargoes of those NTRs lack those motifs, and consensus NLSs/NESs have been reported for only a few NTRs. Crystal structures of NTR-cargo complexes have exemplified 3D structure-dependent binding of cargoes lacking a consensus NLS/NES to different sites on an NTR. Since only a limited number of NTR-cargo interactions have been studied, whether most cargoes lacking a consensus NLS/NES bind to the same confined interface or to various sites on an NTR is still unclear. Addressing this issue, we generated four mutants of transportin-(Trn)SR, of which many cargoes lack a consensus NLS, and eight mutants of Imp13, where no consensus NLS has been defined, and we analyzed their binding to as many as 40 cargo candidates that we previously identified by a nuclear import reaction-based method. The cargoes bind differently to the NTR mutants, suggesting that positions on an NTR contribute differently to the binding of respective cargoes.
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Affiliation(s)
- Makoto Kimura
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan.
| | - Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
| | - Yuriko Morinaka
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Yoshiko Hosono-Sakuma
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Paul Horton
- Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan City, Taiwan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan.
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14
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Kalita J, Kapinos LE, Lim RYH. On the asymmetric partitioning of nucleocytoplasmic transport - recent insights and open questions. J Cell Sci 2021; 134:239102. [PMID: 33912945 DOI: 10.1242/jcs.240382] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macromolecular cargoes are asymmetrically partitioned in the nucleus or cytoplasm by nucleocytoplasmic transport (NCT). At the center of this activity lies the nuclear pore complex (NPC), through which soluble factors circulate to orchestrate NCT. These include cargo-carrying importin and exportin receptors from the β-karyopherin (Kapβ) family and the small GTPase Ran, which switches between guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms to regulate cargo delivery and compartmentalization. Ongoing efforts have shed considerable light on how these soluble factors traverse the NPC permeability barrier to sustain NCT. However, this does not explain how importins and exportins are partitioned in the cytoplasm and nucleus, respectively, nor how a steep RanGTP-RanGDP gradient is maintained across the nuclear envelope. In this Review, we peel away the multiple layers of control that regulate NCT and juxtapose unresolved features against known aspects of NPC function. Finally, we discuss how NPCs might function synergistically with Kapβs, cargoes and Ran to establish the asymmetry of NCT.
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Affiliation(s)
- Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Larisa E Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
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15
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Lokareddy RK, Ko YH, Hong N, Doll SG, Paduch M, Niederweis M, Kossiakoff AA, Cingolani G. Recognition of an α-helical hairpin in P22 large terminase by a synthetic antibody fragment. Acta Crystallogr D Struct Biol 2020; 76:876-888. [PMID: 32876063 PMCID: PMC7466751 DOI: 10.1107/s2059798320009912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 07/20/2020] [Indexed: 11/10/2022] Open
Abstract
The genome-packaging motor of tailed bacteriophages and herpesviruses is a multisubunit protein complex formed by several copies of a large (TerL) and a small (TerS) terminase subunit. The motor assembles transiently at the portal protein vertex of an empty precursor capsid to power the energy-dependent packaging of viral DNA. Both the ATPase and nuclease activities associated with genome packaging reside in TerL. Structural studies of TerL from bacteriophage P22 have been hindered by the conformational flexibility of this enzyme and its susceptibility to proteolysis. Here, an unbiased, synthetic phage-display Fab library was screened and a panel of high-affinity Fabs against P22 TerL were identified. This led to the discovery of a recombinant antibody fragment, Fab4, that binds a 33-amino-acid α-helical hairpin at the N-terminus of TerL with an equilibrium dissociation constant Kd of 71.5 nM. A 1.51 Å resolution crystal structure of Fab4 bound to the TerL epitope (TLE) together with a 1.15 Å resolution crystal structure of the unliganded Fab4, which is the highest resolution ever achieved for a Fab, elucidate the principles governing the recognition of this novel helical epitope. TLE adopts two different conformations in the asymmetric unit and buries as much as 1250 Å2 of solvent-accessible surface in Fab4. TLE recognition is primarily mediated by conformational changes in the third complementarity-determining region of the Fab4 heavy chain (CDR H3) that take place upon epitope binding. It is demonstrated that TLE can be introduced genetically at the N-terminus of a target protein, where it retains high-affinity binding to Fab4.
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Affiliation(s)
- Ravi K. Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, JAH-4E, Philadelphia, PA 19107, USA
| | - Ying-Hui Ko
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, JAH-4E, Philadelphia, PA 19107, USA
| | - Nathaniel Hong
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, JAH-4E, Philadelphia, PA 19107, USA
| | - Steven G. Doll
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, JAH-4E, Philadelphia, PA 19107, USA
| | - Marcin Paduch
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Anthony A. Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, JAH-4E, Philadelphia, PA 19107, USA
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16
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Florio TJ, Lokareddy RK, Gillilan RE, Cingolani G. Molecular Architecture of the Inositol Phosphatase Siw14. Biochemistry 2019; 58:534-545. [PMID: 30548067 DOI: 10.1021/acs.biochem.8b01044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Siw14 is a recently discovered inositol phosphatase implicated in suppressing prion propagation in Saccharomyces cerevisiae. In this paper, we used hybrid structural methods to decipher Siw14 molecular architecture. We found the protein exists in solution as an elongated monomer that is ∼140 Å in length, containing an acidic N-terminal domain and a basic C-terminal dual-specificity phosphatase (DSP) domain, structurally similar to the glycogen phosphatase laforin. The two domains are connected by a protease susceptible linker and do not interact in vitro. The crystal structure of Siw14-DSP reveals a highly basic phosphate-binding loop and an ∼10 Å deep substrate-binding crevice that evolved to dephosphorylate pyro-phosphate moieties. A pseudoatomic model of the full-length phosphatase generated from solution, crystallographic, biochemical, and modeling data sheds light on the interesting zwitterionic nature of Siw14, which we hypothesized may play a role in discriminating negatively charged inositol phosphates.
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Affiliation(s)
- Tyler J Florio
- Department of Biochemistry and Molecular Biology , Thomas Jefferson University , 233 South 10th Street , Philadelphia , Pennsylvania 19107 , United States
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology , Thomas Jefferson University , 233 South 10th Street , Philadelphia , Pennsylvania 19107 , United States
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS) , Cornell University , 161 Synchrotron Drive , Ithaca , New York 14853 , United States
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology , Thomas Jefferson University , 233 South 10th Street , Philadelphia , Pennsylvania 19107 , United States.,Institute of Biomembranes and Bioenergetics , National Research Council , Via Amendola 165/A , 70126 Bari , Italy
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17
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Rodriguez-Bravo V, Pippa R, Song WM, Carceles-Cordon M, Dominguez-Andres A, Fujiwara N, Woo J, Koh AP, Ertel A, Lokareddy RK, Cuesta-Dominguez A, Kim RS, Rodriguez-Fernandez I, Li P, Gordon R, Hirschfield H, Prats JM, Reddy EP, Fatatis A, Petrylak DP, Gomella L, Kelly WK, Lowe SW, Knudsen KE, Galsky MD, Cingolani G, Lujambio A, Hoshida Y, Domingo-Domenech J. Nuclear Pores Promote Lethal Prostate Cancer by Increasing POM121-Driven E2F1, MYC, and AR Nuclear Import. Cell 2018; 174:1200-1215.e20. [PMID: 30100187 DOI: 10.1016/j.cell.2018.07.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/16/2018] [Accepted: 07/10/2018] [Indexed: 12/19/2022]
Abstract
Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome integrity in eukaryotic cells. However, their functional roles in cancer remain poorly understood. We interrogated the evolutionary transcriptomic landscape of NPC components, nucleoporins (Nups), from primary to advanced metastatic human prostate cancer (PC). Focused loss-of-function genetic screen of top-upregulated Nups in aggressive PC models identified POM121 as a key contributor to PC aggressiveness. Mechanistically, POM121 promoted PC progression by enhancing importin-dependent nuclear transport of key oncogenic (E2F1, MYC) and PC-specific (AR-GATA2) transcription factors, uncovering a pharmacologically targetable axis that, when inhibited, decreased tumor growth, restored standard therapy efficacy, and improved survival in patient-derived pre-clinical models. Our studies molecularly establish a role of NPCs in PC progression and give a rationale for NPC-regulated nuclear import targeting as a therapeutic strategy for lethal PC. These findings may have implications for understanding how NPC deregulation contributes to the pathogenesis of other tumor types.
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Affiliation(s)
- Veronica Rodriguez-Bravo
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Raffaella Pippa
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Won-Min Song
- Genetic and Genomic Sciences Department. Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Liver Tumor Translational Research Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Marc Carceles-Cordon
- Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ana Dominguez-Andres
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Naoto Fujiwara
- Liver Tumor Translational Research Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jungreem Woo
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Anna P Koh
- Liver Tumor Translational Research Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Adam Ertel
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Alvaro Cuesta-Dominguez
- Oncological Sciences Department. Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Division of Liver Diseases, Medicine Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rosa S Kim
- Liver Tumor Translational Research Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | | | - Peiyao Li
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ronald Gordon
- Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hadassa Hirschfield
- Liver Tumor Translational Research Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Josep M Prats
- Urology Department, Hospital de Calella, Barcelona 08370, Spain
| | - E Premkumar Reddy
- Oncological Sciences Department. Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alessandro Fatatis
- Pharmacology and Physiology Department, Drexler University, Philadelphia, PA 19104, USA
| | - Daniel P Petrylak
- Medical Oncology Department, Yale Comprehensive Cancer Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Leonard Gomella
- Urology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - W Kevin Kelly
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Urology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Scott W Lowe
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Karen E Knudsen
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Urology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Matthew D Galsky
- Medical Oncology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Amaia Lujambio
- Oncological Sciences Department. Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Division of Liver Diseases, Medicine Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yujin Hoshida
- Liver Tumor Translational Research Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Josep Domingo-Domenech
- Cancer Biology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Medical Oncology Department, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Pathology Department, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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18
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Halakou F, Kilic ES, Cukuroglu E, Keskin O, Gursoy A. Enriching Traditional Protein-protein Interaction Networks with Alternative Conformations of Proteins. Sci Rep 2017; 7:7180. [PMID: 28775330 PMCID: PMC5543104 DOI: 10.1038/s41598-017-07351-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/27/2017] [Indexed: 12/19/2022] Open
Abstract
Traditional Protein-Protein Interaction (PPI) networks, which use a node and edge representation, lack some valuable information about the mechanistic details of biological processes. Mapping protein structures to these PPI networks not only provides structural details of each interaction but also helps us to find the mutual exclusive interactions. Yet it is not a comprehensive representation as it neglects the conformational changes of proteins which may lead to different interactions, functions, and downstream signalling. In this study, we proposed a new representation for structural PPI networks inspecting the alternative conformations of proteins. We performed a large-scale study by creating breast cancer metastasis network and equipped it with different conformers of proteins. Our results showed that although 88% of proteins in our network has at least two structures in Protein Data Bank (PDB), only 22% of them have alternative conformations and the remaining proteins have different regions saved in PDB. However, using even this small set of alternative conformations we observed a considerable increase in our protein docking predictions. Our protein-protein interaction predictions increased from 54% to 76% using the alternative conformations. We also showed the benefits of investigating structural data and alternative conformations of proteins through three case studies.
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Affiliation(s)
- Farideh Halakou
- Department of Computer Engineering, Koc University, Istanbul, 34450, Turkey
| | - Emel Sen Kilic
- Department of Chemical and Biological Engineering, Koc University, Istanbul, 34450, Turkey.,Microbiology, Immunology and Cell Biology Department, West Virginia University, Morgantown, 26505, WV, USA
| | - Engin Cukuroglu
- Computational Sciences and Engineering, Graduate School of Sciences and Engineering, Koc University, Istanbul, 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul, 34450, Turkey
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul, 34450, Turkey.
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19
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Tauchert MJ, Hémonnot C, Neumann P, Köster S, Ficner R, Dickmanns A. Impact of the crystallization condition on importin-β conformation. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:705-17. [DOI: 10.1107/s2059798316004940] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/23/2016] [Indexed: 11/10/2022]
Abstract
In eukaryotic cells, the exchange of macromolecules between the nucleus and cytoplasm is highly selective and requires specialized soluble transport factors. Many of them belong to the importin-β superfamily, the members of which share an overall superhelical structure owing to the tandem arrangement of a specific motif, the HEAT repeat. This structural organization leads to great intrinsic flexibility, which in turn is a prerequisite for the interaction with a variety of proteins and for its transport function. During the passage from the aqueous cytosol into the nucleus, the receptor passes the gated channel of the nuclear pore complex filled with a protein meshwork of unknown organization, which seems to be highly selective owing to the presence of FG-repeats, which are peptides with hydrophobic patches. Here, the structural changes of free importin-β from a single organism, crystallized in polar (salt) or apolar (PEG) buffer conditions, are reported. This allowed analysis of the structural changes, which are attributable to the surrounding milieu and are not affected by bound interaction partners. The importin-β structures obtained exhibit significant conformational changes and suggest an influence of the polarity of the environment, resulting in an extended conformation in the PEG condition. The significance of this observation is supported by SAXS experiments and the analysis of other crystal structures of importin-β deposited in the Protein Data Bank.
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20
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Halder K, Dölker N, Van Q, Gregor I, Dickmanns A, Baade I, Kehlenbach RH, Ficner R, Enderlein J, Grubmüller H, Neumann H. MD simulations and FRET reveal an environment-sensitive conformational plasticity of importin-β. Biophys J 2016. [PMID: 26200863 DOI: 10.1016/j.bpj.2015.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The nuclear pore complex mediates nucleocytoplasmic transport of macromolecules in eukaryotic cells. Transport through the pore is restricted by a hydrophobic selectivity filter comprising disordered phenylalanine-glycine-rich repeats of nuclear pore proteins. Exchange through the pore requires specialized transport receptors, called exportins and importins, that interact with cargo proteins in a RanGTP-dependent manner. These receptors are highly flexible superhelical structures composed of HEAT-repeat motifs that adopt various degrees of extension in crystal structures. Here, we performed molecular-dynamics simulations using crystal structures of Importin-β in its free form or in complex with nuclear localization signal peptides as the starting conformation. Our simulations predicted that initially compact structures would adopt extended conformations in hydrophilic buffers, while contracted conformations would dominate in more hydrophobic solutions, mimicking the environment of the nuclear pore. We confirmed this experimentally by Förster resonance energy transfer experiments using dual-fluorophore-labeled Importin-β. These observations explain seemingly contradictory crystal structures and suggest a possible mechanism for cargo protection during passage of the nuclear pore. Such hydrophobic switching may be a general principle for environmental control of protein function.
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Affiliation(s)
- Kangkan Halder
- Free Floater (Junior) Research Group "Applied Synthetic Biology", Institute for Microbiology and Genetics, Georg-August University Göttingen, Göttingen, Germany
| | - Nicole Dölker
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Qui Van
- Third Institute of Physics-Biophysics, Georg-August University Göttingen, Göttingen, Germany
| | - Ingo Gregor
- Third Institute of Physics-Biophysics, Georg-August University Göttingen, Göttingen, Germany
| | - Achim Dickmanns
- Institute for Microbiology and Genetics, Department of Molecular Structural Biology, Georg-August University Göttingen, Göttingen, Germany
| | - Imke Baade
- Department of Molecular Biology, Faculty of Medicine, Georg-August University Göttingen, Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August University Göttingen, Göttingen, Germany
| | - Ralf Ficner
- Institute for Microbiology and Genetics, Department of Molecular Structural Biology, Georg-August University Göttingen, Göttingen, Germany
| | - Jörg Enderlein
- Third Institute of Physics-Biophysics, Georg-August University Göttingen, Göttingen, Germany
| | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Heinz Neumann
- Free Floater (Junior) Research Group "Applied Synthetic Biology", Institute for Microbiology and Genetics, Georg-August University Göttingen, Göttingen, Germany.
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21
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Honcharenko M, Bestas B, Jezowska M, Wojtczak BA, Moreno PMD, Romanowska J, Bächle SM, Darzynkiewicz E, Jemielity J, Smith CIE, Strömberg R. Synthetic m3G-CAP attachment necessitates a minimum trinucleotide constituent to be recognised as a nuclear import signal. RSC Adv 2016. [DOI: 10.1039/c6ra09568b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Minimal requirement for Snurportin based nuclear uptake is the inclusion of a trinucleotide sequence between the m3G-CAP and the artificial linker.
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22
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Abstract
The Karyopherin-β family of proteins mediates nuclear transport of macromolecules. Nuclear versus cytoplasmic localization of proteins is often suggested by the presence of NLSs (nuclear localization signals) or NESs (nuclear export signals). Import-Karyopherin-βs or Importins bind to NLSs in their protein cargos to transport them through nuclear pore complexes into the nucleus. Until recently, only two classes of NLS had been biochemically and structurally characterized: the classical NLS, which is recognized by the Importin-α/β heterodimer and the PY-NLS (proline-tyrosine NLS), which is recognized by Karyopherin-β2 or Transportin-1. Structures of two other Karyopherin-βs, Kap121 and Transportin-SR2, in complex with their respective cargos were reported for the first time recently, revealing two new distinct classes of NLSs. The present paper briefly describes the classical NLS, reviews recent literature on the PY-NLS and provides in-depth reviews of the two newly discovered classes of NLSs that bind Kap121p and Transportin-SR respectively.
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23
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McNulty R, Lokareddy RK, Roy A, Yang Y, Lander GC, Heck AJR, Johnson JE, Cingolani G. Architecture of the Complex Formed by Large and Small Terminase Subunits from Bacteriophage P22. J Mol Biol 2015; 427:3285-3299. [PMID: 26301600 DOI: 10.1016/j.jmb.2015.08.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/14/2015] [Accepted: 08/15/2015] [Indexed: 11/27/2022]
Abstract
Packaging of viral genomes inside empty procapsids is driven by a powerful ATP-hydrolyzing motor, formed in many double-stranded DNA viruses by a complex of a small terminase (S-terminase) subunit and a large terminase (L-terminase) subunit, transiently docked at the portal vertex during genome packaging. Despite recent progress in elucidating the structure of individual terminase subunits and their domains, little is known about the architecture of an assembled terminase complex. Here, we describe a bacterial co-expression system that yields milligram quantities of the S-terminase:L-terminase complex of the Salmonella phage P22. In vivo assembled terminase complex was affinity-purified and stabilized by addition of non-hydrolyzable ATP, which binds specifically to the ATPase domain of L-terminase. Mapping studies revealed that the N-terminus of L-terminase ATPase domain (residues 1-58) contains a minimal S-terminase binding domain sufficient for stoichiometric association with residues 140-162 of S-terminase, the L-terminase binding domain. Hydrodynamic analysis by analytical ultracentrifugation sedimentation velocity and native mass spectrometry revealed that the purified terminase complex consists predominantly of one copy of the nonameric S-terminase bound to two equivalents of L-terminase (1S-terminase:2L-terminase). Direct visualization of this molecular assembly in negative-stained micrographs yielded a three-dimensional asymmetric reconstruction that resembles a "nutcracker" with two L-terminase protomers projecting from the C-termini of an S-terminase ring. This is the first direct visualization of a purified viral terminase complex analyzed in the absence of DNA and procapsid.
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Affiliation(s)
- Reginald McNulty
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Ravi Kumar Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street Philadelphia, PA 19107, USA
| | - Ankoor Roy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street Philadelphia, PA 19107, USA
| | - Yang Yang
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - John E Johnson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street Philadelphia, PA 19107, USA.
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24
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Lokareddy RK, Hapsari RA, van Rheenen M, Pumroy RA, Bhardwaj A, Steen A, Veenhoff LM, Cingolani G. Distinctive Properties of the Nuclear Localization Signals of Inner Nuclear Membrane Proteins Heh1 and Heh2. Structure 2015; 23:1305-1316. [PMID: 26051712 DOI: 10.1016/j.str.2015.04.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/23/2015] [Accepted: 04/23/2015] [Indexed: 01/13/2023]
Abstract
Targeting of ER-synthesized membrane proteins to the inner nuclear membrane (INM) has long been explained by the diffusion-retention model. However, several INM proteins contain non-classical nuclear localization signal (NLS) sequences, which, in a few instances, have been shown to promote importin α/β- and Ran-dependent translocation to the INM. Here, using structural and biochemical methods, we show that yeast INM proteins Heh2 and Src1/Heh1 contain bipartite import sequences that associate intimately with the minor NLS-binding pocket of yeast importin α and unlike classical NLSs efficiently displace the IBB domain in the absence of importin β. In vivo, the intimate interactions at the minor NLS-binding pocket make the h2NLS highly efficient at recruiting importin α at the ER and drive INM localization of endogenous Heh2. Thus, h1/h2NLSs delineate a novel class of super-potent, IBB-like membrane protein NLSs, distinct from classical NLSs found in soluble cargos and of general interest in biology.
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Affiliation(s)
- Ravi K Lokareddy
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10 Street, Philadelphia, PA 19107, USA
| | - Rizqiya A Hapsari
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.,Zernike Institute for Advanced Materials, Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Mathilde van Rheenen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Ruth A Pumroy
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10 Street, Philadelphia, PA 19107, USA
| | - Anshul Bhardwaj
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10 Street, Philadelphia, PA 19107, USA
| | - Anton Steen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Gino Cingolani
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10 Street, Philadelphia, PA 19107, USA
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25
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Fung HYJ, Chook YM. Atomic basis of CRM1-cargo recognition, release and inhibition. Semin Cancer Biol 2014; 27:52-61. [PMID: 24631835 PMCID: PMC4108548 DOI: 10.1016/j.semcancer.2014.03.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/01/2014] [Indexed: 11/19/2022]
Abstract
CRM1 or XPO1 is the major nuclear export receptor in the cell, which controls the nuclear-cytoplasmic localization of many proteins and RNAs. CRM1 is also a promising cancer drug target as the transport receptor is overexpressed in many cancers where some of its cargos are misregulated and mislocalized to the cytoplasm. Atomic level understanding of CRM1 function has greatly facilitated recent drug discovery and development of CRM1 inhibitors to target a variety of malignancies. Numerous atomic resolution CRM1 structures are now available, explaining how the exporter recognizes nuclear export signals in its cargos, how RanGTP and cargo bind with positive cooperativity, how RanBP1 causes release of export cargos in the cytoplasm and how diverse inhibitors such as Leptomycin B and the new KPT-SINE compounds block nuclear export. This review summarizes structure-function studies that explain CRM1-cargo recognition, release and inhibition.
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Affiliation(s)
- Ho Yee Joyce Fung
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park, Dallas, TX 75390-9041, USA.
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park, Dallas, TX 75390-9041, USA.
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26
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Martinelli C, Colombo E, Piccini D, Sironi C, Pelicci PG, de Marco A. An intrabody specific for the nucleophosmin carboxy-terminal mutant and fused to a nuclear localization sequence binds its antigen but fails to relocate it in the nucleus. ACTA ACUST UNITED AC 2014. [PMID: 28626645 PMCID: PMC5466097 DOI: 10.1016/j.btre.2014.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A scFv intrabody specific for the NPMc+ mutant NES sequence was isolated. It was expressed as a fusion with a NLS and such construct accumulates in the nucleus. The scFv-NLS fusion binds its antigen in the cytoplasm of eukaryotic cells. The complex shuttles to the nucleus but accumulates in the cytoplasm. Stronger NLS should be developed to revert the strength of pathogenic NES.
The cytoplasmic accumulation of NPM1 (NPMc+) is found in acute myeloid leukemia (AML) with NPM1 mutation. NPM1 must shuttle between nucleus and cytoplasm to assure physiological protein synthesis and, therefore, the elimination of NPMc+ is not a suitable therapeutic option. We isolated, characterized, and produced a functional scFv intrabody fused to nuclear localization signal(s) (NLS) that does not recognize NPM1 but binds to the mutant-specific C-terminal NES (nuclear export signal) of NPMc+, responsible for its cytoplasmic accumulation. The scFv-NLS fusion accumulated in the nuclei of wild type cells and strongly bound to its antigen in the cytoplasm of NPMc+ expressing cells. However, it failed to relocate the majority of NPMc+ in the nucleus, even when fused to four NLS. Our results show the technical feasibility of producing recombinant intrabodies with defined sub-cellular targeting and nuclear accumulation but the lack of information concerning the features that confer variable strength to the signal peptides impairs the development of biomolecules able to counteract pathological sub-cellular distribution of shuttling proteins.
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Affiliation(s)
| | - Emanuela Colombo
- Department of Experimental Oncology, IEO, Via Adamello 16, 20139 Milan, Italy.,Department of Health Sciences, University of Milan, 20133 Milan, Italy
| | | | - Cristina Sironi
- Department of Experimental Oncology, IEO, Via Adamello 16, 20139 Milan, Italy
| | - Pier Giuseppe Pelicci
- Department of Experimental Oncology, IEO, Via Adamello 16, 20139 Milan, Italy.,Department of Health Sciences, University of Milan, 20133 Milan, Italy
| | - Ario de Marco
- Department of Biomedical Sciences and Engineering, University of Nova Gorica, Glavni Trg 9, SI-5261 Vipava, Slovenia
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27
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Yoon JY, Lee SJ, Kim DJ, Lee BJ, Yang JK, Suh SW. Crystal structure of JHP933 fromHelicobacter pyloriJ99 shows two-domain architecture with a DUF1814 family nucleotidyltransferase domain and a helical bundle domain. Proteins 2014; 82:2275-81. [DOI: 10.1002/prot.24572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/03/2014] [Accepted: 03/21/2014] [Indexed: 01/26/2023]
Affiliation(s)
- Ji Young Yoon
- Department of Chemistry; College of Natural Sciences, Seoul National University; Seoul 151-742 Republic of Korea
| | - Sang Jae Lee
- The Research Institute of Pharmaceutical Sciences; College of Pharmacy, Seoul National University, Gwanak-gu; Seoul 151-742 Republic of Korea
| | - Do Jin Kim
- Department of Chemistry; College of Natural Sciences, Seoul National University; Seoul 151-742 Republic of Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences; College of Pharmacy, Seoul National University, Gwanak-gu; Seoul 151-742 Republic of Korea
| | - Jin Kuk Yang
- Department of Chemistry; College of Natural Sciences, Soongsil University; Seoul 156-743 Republic of Korea
| | - Se Won Suh
- Department of Chemistry; College of Natural Sciences, Seoul National University; Seoul 151-742 Republic of Korea
- Department of Biophysics and Chemical Biology; College of Natural Sciences, Seoul National University; Seoul 151-742 Republic of Korea
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28
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Angus L, van der Watt PJ, Leaner VD. Inhibition of the nuclear transporter, Kpnβ1, results in prolonged mitotic arrest and activation of the intrinsic apoptotic pathway in cervical cancer cells. Carcinogenesis 2014; 35:1121-31. [PMID: 24398670 DOI: 10.1093/carcin/bgt491] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The karyopherin β proteins are involved in nuclear-cytoplasmic trafficking and are crucial for protein and RNA subcellular localization. We previously showed that Kpnβ1, a nuclear importin protein, is overexpressed in cervical cancer and is critical for cervical cancer cell survival and proliferation, whereas non-cancer cells are less dependent on its expression. This study aimed to identify the mechanisms by which inhibition of Kpnβ1 results in cervical cancer cell death. We show that the inhibition of Kpnβ1 results in the induction of apoptosis and a prolonged mitotic arrest, accompanied by distinct mitotic defects in cervical cancer cells but not non-cancer cells. In cervical cancer cells, Kpnβ1 downregulation results in sustained degradation of the antiapoptotic protein, Mcl-1, and elevated Noxa expression, as well as mitochondrial membrane permeabilization resulting in the release of cytochrome C and activation of associated caspases. Although p53 becomes stabilized in Kpnβ1 knockdown cervical cancer cells, apoptosis occurs in a p53-independent manner. These results demonstrate that blocking Kpnβ1 has potential as an anticancer therapeutic approach.
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Affiliation(s)
- Liselotte Angus
- Division of Medical Biochemistry, Faculty of Health Sciences, University of Cape Town, Institute of Infectious Disease and Molecular Medicine, Cape Town 7925, South Africa
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29
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Choi S, Song J, Son SY, Park IY, Yamashita E, Lee SJ. Crystallization and preliminary X-ray diffraction analysis of human importin β-Snail zinc finger domain complex. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1049-51. [PMID: 23989161 DOI: 10.1107/s1744309113023038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/15/2013] [Indexed: 11/10/2022]
Abstract
Snail is a C2H2-type zinc finger transcriptional repressor that induces epithelial-mesenchymal transition by repression of E-cadherin expression levels during embryonic development and tumour progression. Snail is imported into the nucleus by importin β through direct binding with its four zinc finger domain. The complex between importin β and Snail four zinc finger domain was crystallized in order to understand the nuclear transport mechanism of Snail. The constituents of the complex were separately expressed and were then co-purified and crystallized by the hanging-drop vapour-diffusion method. The crystals belonged to space group C2, with unit-cell parameters a = 228.2, b = 77.5, c = 72.0 Å, β = 100.9° and diffracted to 2.5 Å resolution.
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Affiliation(s)
- Saehae Choi
- College of Pharmacy, Chungbuk National University, 410 Seungbong, Heungduk, Cheongju 361-763, Republic of Korea
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30
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Natalizio AH, Matera AG. Identification and characterization of Drosophila Snurportin reveals a role for the import receptor Moleskin/importin-7 in snRNP biogenesis. Mol Biol Cell 2013; 24:2932-42. [PMID: 23885126 PMCID: PMC3771954 DOI: 10.1091/mbc.e13-03-0118] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous work established Importin-β and Snurportin1 as the vertebrate snRNP import receptor and adaptor proteins, respectively. This study identifies Drosophila Snurportin and shows that it uses an alternative import receptor, Importin7/Moleskin. Moleskin is required for the stability of other snRNP biogenesis factors. Nuclear import is an essential step in small nuclear ribonucleoprotein (snRNP) biogenesis. Snurportin1 (SPN1), the import adaptor, binds to trimethylguanosine (TMG) caps on spliceosomal small nuclear RNAs. Previous studies indicated that vertebrate snRNP import requires importin-β, the transport receptor that binds directly to SPN1. We identify CG42303/snup as the Drosophila orthologue of human snurportin1 (SNUPN). Of interest, the importin-β binding (IBB) domain of SPN1, which is essential for TMG cap–mediated snRNP import in humans, is not well conserved in flies. Consistent with its lack of an IBB domain, we find that Drosophila SNUP (dSNUP) does not interact with Ketel/importin-β. Fruit fly snRNPs also fail to bind Ketel; however, the importin-7 orthologue Moleskin (Msk) physically associates with both dSNUP and spliceosomal snRNPs and localizes to nuclear Cajal bodies. Strikingly, we find that msk-null mutants are depleted of the snRNP assembly factor, survival motor neuron, and the Cajal body marker, coilin. Consistent with a loss of snRNP import function, long-lived msk larvae show an accumulation of TMG cap signal in the cytoplasm. These data indicate that Ketel/importin-β does not play a significant role in Drosophila snRNP import and demonstrate a crucial function for Msk in snRNP biogenesis.
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Affiliation(s)
- Amanda Hicks Natalizio
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599 Departments of Biology, University of North Carolina, Chapel Hill, NC 27599 Departments of Genetics, University of North Carolina, Chapel Hill, NC 27599 Program in Molecular Biology and Biotechnology, University of North Carolina, Chapel Hill, NC 27599 Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
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31
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Østrup O, Olbricht G, Østrup E, Hyttel P, Collas P, Cabot R. RNA profiles of porcine embryos during genome activation reveal complex metabolic switch sensitive to in vitro conditions. PLoS One 2013; 8:e61547. [PMID: 23637850 PMCID: PMC3639270 DOI: 10.1371/journal.pone.0061547] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 03/11/2013] [Indexed: 11/18/2022] Open
Abstract
Fertilization is followed by complex changes in cytoplasmic composition and extensive chromatin reprogramming which results in the abundant activation of totipotent embryonic genome at embryonic genome activation (EGA). While chromatin reprogramming has been widely studied in several species, only a handful of reports characterize changing transcriptome profiles and resulting metabolic changes in cleavage stage embryos. The aims of the current study were to investigate RNA profiles of in vivo developed (ivv) and in vitro produced (ivt) porcine embryos before (2-cell stage) and after (late 4-cell stage) EGA and determine major metabolic changes that regulate totipotency. The period before EGA was dominated by transcripts responsible for cell cycle regulation, mitosis, RNA translation and processing (including ribosomal machinery), protein catabolism, and chromatin remodelling. Following EGA an increase in the abundance of transcripts involved in transcription, translation, DNA metabolism, histone and chromatin modification, as well as protein catabolism was detected. The further analysis of members of overlapping GO terms revealed that despite that comparable cellular processes are taking place before and after EGA (RNA splicing, protein catabolism), different metabolic pathways are involved. This strongly suggests that a complex metabolic switch accompanies EGA. In vitro conditions significantly altered RNA profiles before EGA, and the character of these changes indicates that they originate from oocyte and are imposed either before oocyte aspiration or during in vitro maturation. IVT embryos have altered content of apoptotic factors, cell cycle regulation factors and spindle components, and transcription factors, which all may contribute to reduced developmental competence of embryos produced in vitro. Overall, our data are in good accordance with previously published, genome-wide profiling data in other species. Moreover, comparison with mouse and human embryos showed striking overlap in functional annotation of transcripts during the EGA, suggesting conserved basic mechanisms regulating establishment of totipotency in mammalian development.
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Affiliation(s)
- Olga Østrup
- Institute for Basic Medical Sciences, Faculty of Medicine, University of Oslo and Norwegian Center for Stem Cell Research, Oslo, Norway.
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32
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Structural bioinformatics of the general transcription factor TFIID. Biochimie 2013; 95:680-91. [DOI: 10.1016/j.biochi.2012.10.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 10/29/2012] [Indexed: 11/19/2022]
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33
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Structural basis for the nuclear export activity of Importin13. EMBO J 2013; 32:899-913. [PMID: 23435562 DOI: 10.1038/emboj.2013.29] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/28/2013] [Indexed: 02/05/2023] Open
Abstract
Importin13 (Imp13) is a bidirectional karyopherin that can mediate both import and export of cargoes. Imp13 recognizes several import cargoes, which include the exon junction complex components Mago-Y14 and the E2 SUMO-conjugating enzyme Ubc9, and one known export cargo, the translation initiation factor 1A (eIF1A). To understand how Imp13 can perform double duty, we determined the 3.6-Å crystal structure of Imp13 in complex with RanGTP and with eIF1A. eIF1A binds at the inner surface of the Imp13 C-terminal arch adjacent and concomitantly to RanGTP illustrating how eIF1A can be exported by Imp13. Moreover, the 3.0-Å structure of Imp13 in its unbound state reveals the existence of an open conformation in the cytoplasm that explains export cargo release and completes the export branch of the Imp13 pathway. Finally, we demonstrate that Imp13 is able to bind and export eIF1A in vivo and that its function is essential.
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34
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Larue R, Gupta K, Wuensch C, Shkriabai N, Kessl JJ, Danhart E, Feng L, Taltynov O, Christ F, Van Duyne GD, Debyser Z, Foster MP, Kvaratskhelia M. Interaction of the HIV-1 intasome with transportin 3 protein (TNPO3 or TRN-SR2). J Biol Chem 2012; 287:34044-58. [PMID: 22872640 PMCID: PMC3464514 DOI: 10.1074/jbc.m112.384669] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/01/2012] [Indexed: 01/14/2023] Open
Abstract
Transportin 3 (TNPO3 or TRN-SR2) has been shown to be an important cellular factor for early steps of lentiviral replication. However, separate studies have implicated distinct mechanisms for TNPO3 either through its interaction with HIV-1 integrase or capsid. Here we have carried out a detailed biophysical characterization of TNPO3 and investigated its interactions with viral proteins. Biophysical analyses including circular dichroism, analytical ultracentrifugation, small-angle x-ray scattering, and homology modeling provide insight into TNPO3 architecture and indicate that it is highly structured and exists in a monomer-dimer equilibrium in solution. In vitro biochemical binding assays argued against meaningful direct interaction between TNPO3 and the capsid cores. Instead, TNPO3 effectively bound to the functional intasome but not to naked viral DNA, suggesting that TNPO3 can directly engage the HIV-1 IN tetramer prebound to the cognate DNA. Mass spectrometry-based protein footprinting and site-directed mutagenesis studies have enabled us to map several interacting amino acids in the HIV-1 IN C-terminal domain and the cargo binding domain of TNPO3. Our findings provide important information for future genetic analysis to better understand the role of TNPO3 and its interacting partners for HIV-1 replication.
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Affiliation(s)
- Ross Larue
- From the Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy and
| | - Kushol Gupta
- the Department of Biochemistry and Biophysics and The Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, and
| | - Christiane Wuensch
- From the Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy and
| | - Nikolozi Shkriabai
- From the Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy and
| | - Jacques J. Kessl
- From the Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy and
| | - Eric Danhart
- the Department of Chemistry,The Ohio State University, Columbus, Ohio 43210
| | - Lei Feng
- From the Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy and
| | - Oliver Taltynov
- the Division of Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Flanders 3000, Belgium
| | - Frauke Christ
- the Division of Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Flanders 3000, Belgium
| | - Gregory D. Van Duyne
- the Department of Biochemistry and Biophysics and The Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, and
| | - Zeger Debyser
- the Division of Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Flanders 3000, Belgium
| | - Mark P. Foster
- the Department of Chemistry,The Ohio State University, Columbus, Ohio 43210
| | - Mamuka Kvaratskhelia
- From the Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy and
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35
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Pumroy RA, Nardozzi JD, Hart DJ, Root MJ, Cingolani G. Nucleoporin Nup50 stabilizes closed conformation of armadillo repeat 10 in importin α5. J Biol Chem 2011; 287:2022-31. [PMID: 22130666 DOI: 10.1074/jbc.m111.315838] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The human genome encodes six isoforms of importin α that show greater than 60% sequence similarity and remarkable substrate specificity. The isoform importin α5 can bind phosphorylated cargos such as STAT1 and Epstein-Barr Virus Nuclear Antigen 1, as well as the influenza virus polymerase subunit PB2. In this work, we have studied the interaction of the nucleoporin Nup50 with importin α5. We show that the first 47 residues of Nup50 bind to the C terminus of importin α5 like a "clip," stabilizing the closed conformation of ARM 10. In vitro, Nup50 binds with high affinity either to empty importin α5 or to a preassembled complex of importin α5 bound to the C-terminal domain of the import cargo PB2, resulting in a trimeric complex. By contrast, PB2 can only bind with high affinity to importin α5 in the absence of Nup50. This suggests that Nup50 primary function may not be to actively displace the import cargo from importin α5 but rather to prevent cargo rebinding in preparation for recycling. This is the first evidence for a nucleoporin modulating the import reaction by directly altering the three-dimensional structure of an import adaptor.
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Affiliation(s)
- Ruth A Pumroy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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36
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Savulescu AF, Shorer H, Kleifeld O, Cohen I, Gruber R, Glickman MH, Harel A. Nuclear import of an intact preassembled proteasome particle. Mol Biol Cell 2011; 22:880-91. [PMID: 21289101 PMCID: PMC3057711 DOI: 10.1091/mbc.e10-07-0595] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nuclear targeting of intact proteasome particles was tested in the Xenopus egg extract system. Both the 26S proteasome holoenzyme and the 20S core particle were targeted to the nuclear envelope but could not enter the nucleus. A novel proteolytically active 20S+ particle was actively imported into the nucleoplasm in a Ran-independent fashion. The 26S proteasome is a conserved 2.5 MDa protein degradation machine that localizes to different cellular compartments, including the nucleus. Little is known about the specific targeting mechanisms of proteasomes in eukaryotic cells. We used a cell-free nuclear reconstitution system to test for nuclear targeting and import of distinct proteasome species. Three types of stable, proteolytically active proteasomes particles were purified from Xenopus egg cytosol. Two of these, the 26S holoenzyme and the 20S core particle, were targeted to the nuclear periphery but did not reach the nucleoplasm. This targeting depends on the presence of mature nuclear pore complexes (NPCs) in the nuclear envelope. A third, novel form, designated here as 20S+, was actively imported through NPCs. The 20S+ proteasome particle resembles recently described structural intermediates from other systems. Nuclear import of this particle requires functional NPCs, but it is not directly regulated by the Ran GTPase cycle. The mere presence of the associated “+” factors is sufficient to reconstitute nuclear targeting and confer onto isolated 20S core particles the ability to be imported. Stable 20S+ particles found in unfertilized eggs may provide a means for quick mobilization of existing proteasome particles into newly formed nuclear compartments during early development.
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Affiliation(s)
- Anca F Savulescu
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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37
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Kaláb P, Solc P, Motlík J. The role of RanGTP gradient in vertebrate oocyte maturation. Results Probl Cell Differ 2011; 53:235-67. [PMID: 21630149 DOI: 10.1007/978-3-642-19065-0_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The maturation of vertebrate oocyte into haploid gamete, the egg, consists of two specialized asymmetric cell divisions with no intervening S-phase. Ran GTPase has an essential role in relaying the active role of chromosomes in their own segregation by the meiotic process. In addition to its conserved role as a key regulator of macromolecular transport between nucleus and cytoplasm, Ran has important functions during cell division, including in mitotic spindle assembly and in the assembly of nuclear envelope at the exit from mitosis. The cellular functions of Ran are mediated by RanGTP interactions with nuclear transport receptors (NTRs) related to importin β and depend on the existence of chromosome-centered RanGTP gradient. Live imaging with FRET biosensors indeed revealed the existence of RanGTP gradient throughout mouse oocyte maturation. NTR-dependent transport of cell cycle regulators including cyclin B1, Wee2, and Cdc25B between the oocyte cytoplasm and germinal vesicle (GV) is required for normal resumption of meiosis. After GVBD in mouse oocytes, RanGTP gradient is required for timely meiosis I (MI) spindle assembly and provides long-range signal directing egg cortex differentiation. However, RanGTP gradient is not required for MI spindle migration and may be dispensable for MI spindle function in chromosome segregation. In contrast, MII spindle assembly and function in maturing mouse and Xenopus laevis eggs depend on RanGTP gradient, similar to X. laevis MII-derived egg extracts.
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Affiliation(s)
- Petr Kaláb
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892-4256, USA.
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38
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Structure of Importin13-Ubc9 complex: nuclear import and release of a key regulator of sumoylation. EMBO J 2010; 30:427-38. [PMID: 21139563 DOI: 10.1038/emboj.2010.320] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 11/10/2010] [Indexed: 01/09/2023] Open
Abstract
Importin13 (Imp13) is an unusual β-karyopherin that is able to both import and export cargoes in and out of the nucleus. In the cytoplasm, Imp13 associates with different cargoes such as Mago-Y14 and Ubc9, and facilitates their import into the nucleus where RanGTP binding promotes the release of the cargo. In this study, we present the 2.8 Å resolution crystal structure of Imp13 in complex with the SUMO E2-conjugating enzyme, Ubc9. The structure shows an uncommon mode of cargo-karyopherin recognition with Ubc9 binding at the N-terminal portion of Imp13, occupying the entire RanGTP-binding site. Comparison of the Imp13-Ubc9 complex with Imp13-Mago-Y14 shows the remarkable plasticity of Imp13, whose conformation changes from a closed ring to an open superhelix when bound to the two different cargoes. The structure also shows that the binding mode is compatible with the sumoylated states of Ubc9. Indeed, we find that Imp13 is able to bind sumoylated Ubc9 in vitro and suppresses autosumoylation activity in the complex.
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Lott K, Cingolani G. The importin β binding domain as a master regulator of nucleocytoplasmic transport. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1578-92. [PMID: 21029753 DOI: 10.1016/j.bbamcr.2010.10.012] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 10/11/2010] [Accepted: 10/19/2010] [Indexed: 12/16/2022]
Abstract
Specific and efficient recognition of import cargoes is essential to ensure nucleocytoplasmic transport. To this end, the prototypical karyopherin importin β associates with import cargoes directly or, more commonly, through import adaptors, such as importin α and snurportin. Adaptor proteins bind the nuclear localization sequence (NLS) of import cargoes while recruiting importin β via an N-terminal importin β binding (IBB) domain. The use of adaptors greatly expands and amplifies the repertoire of cellular cargoes that importin β can efficiently import into the cell nucleus and allows for fine regulation of nuclear import. Accordingly, the IBB domain is a dedicated NLS, unique to adaptor proteins that functions as a molecular liaison between importin β and import cargoes. This review provides an overview of the molecular role played by the IBB domain in orchestrating nucleocytoplasmic transport. Recent work has determined that the IBB domain has specialized functions at every step of the import and export pathway. Unexpectedly, this stretch of ~40 amino acids plays an essential role in regulating processes such as formation of the import complex, docking and translocation through the nuclear pore complex (NPC), release of import cargoes into the cell nucleus and finally recycling of import adaptors and importin β into the cytoplasm. Thus, the IBB domain is a master regulator of nucleocytoplasmic transport, whose complex molecular function is only recently beginning to emerge. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Kaylen Lott
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107, USA
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40
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Chook YM, Süel KE. Nuclear import by karyopherin-βs: recognition and inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1593-606. [PMID: 21029754 DOI: 10.1016/j.bbamcr.2010.10.014] [Citation(s) in RCA: 300] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/06/2010] [Accepted: 10/19/2010] [Indexed: 01/24/2023]
Abstract
Proteins in the karyopherin-β family mediate the majority of macromolecular transport between the nucleus and the cytoplasm. Eleven of the 19 known human karyopherin-βs and 10 of the 14S. cerevisiae karyopherin-βs mediate nuclear import through recognition of nuclear localization signals or NLSs in their cargos. This receptor-mediated process is essential to cellular viability as proteins are translated in the cytoplasm but many have functional roles in the nucleus. Many known karyopherin-β-cargo interactions were discovered through studies of the individual cargos rather than the karyopherins, and this information is thus widely scattered in the literature. We consolidate information about cargos that are directly recognized by import-karyopherin-βs and review common characteristics or lack thereof among cargos of different import pathways. Knowledge of karyopherin-β-cargo interactions is also critical for the development of nuclear import inhibitors and the understanding of their mechanisms of inhibition. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Yuh Min Chook
- Department of Pharmacology, University of Texas Southerwestern Medical Center, Dallas, TX 75206, USA.
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41
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Marfori M, Mynott A, Ellis JJ, Mehdi AM, Saunders NFW, Curmi PM, Forwood JK, Bodén M, Kobe B. Molecular basis for specificity of nuclear import and prediction of nuclear localization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1562-77. [PMID: 20977914 DOI: 10.1016/j.bbamcr.2010.10.013] [Citation(s) in RCA: 303] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 10/15/2010] [Accepted: 10/19/2010] [Indexed: 01/03/2023]
Abstract
Although proteins are translated on cytoplasmic ribosomes, many of these proteins play essential roles in the nucleus, mediating key cellular processes including but not limited to DNA replication and repair as well as transcription and RNA processing. Thus, understanding how these critical nuclear proteins are accurately targeted to the nucleus is of paramount importance in biology. Interaction and structural studies in the recent years have jointly revealed some general rules on the specificity determinants of the recognition of nuclear targeting signals by their specific receptors, at least for two nuclear import pathways: (i) the classical pathway, which involves the classical nuclear localization sequences (cNLSs) and the receptors importin-α/karyopherin-α and importin-β/karyopherin-β1; and (ii) the karyopherin-β2 pathway, which employs the proline-tyrosine (PY)-NLSs and the receptor transportin-1/karyopherin-β2. The understanding of specificity rules allows the prediction of protein nuclear localization. We review the current understanding of the molecular determinants of the specificity of nuclear import, focusing on the importin-α•cargo recognition, as well as the currently available databases and predictive tools relevant to nuclear localization. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Mary Marfori
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
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42
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Hintersteiner M, Ambrus G, Bednenko J, Schmied M, Knox AJS, Meisner NC, Gstach H, Seifert JM, Singer EL, Gerace L, Auer M. Identification of a small molecule inhibitor of importin β mediated nuclear import by confocal on-bead screening of tagged one-bead one-compound libraries. ACS Chem Biol 2010; 5:967-79. [PMID: 20677820 DOI: 10.1021/cb100094k] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In eukaryotic cells, proteins and RNAs are transported between the nucleus and the cytoplasm by nuclear import and export receptors. Over the past decade, small molecules that inhibit the nuclear export receptor CRM1 have been identified, most notably leptomycin B. However, up to now no small molecule inhibitors of nuclear import have been described. Here we have used our automated confocal nanoscanning and bead picking method (CONA) for on-bead screening of a one-bead one-compound library to identify the first such import inhibitor, karyostatin 1A. Karyostatin 1A binds importin β with high nanomolar affinity and specifically inhibits importin α/β mediated nuclear import at low micromolar concentrations in vitro and in living cells, without perturbing transportin mediated nuclear import or CRM1 mediated nuclear export. Surface plasmon resonance binding experiments suggest that karyostatin 1A acts by disrupting the interaction between importin β and the GTPase Ran. As a selective inhibitor of the importin α/β import pathway, karyostatin 1A will provide a valuable tool for future studies of nucleocytoplasmic trafficking.
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Affiliation(s)
- Martin Hintersteiner
- The University of Edinburgh, School of Biological Sciences (CSE) and School of Biomedical Sciences (CMVM), CH Waddington Building, 3.07, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JD, U.K
| | - Géza Ambrus
- Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037
| | - Janna Bednenko
- Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037
| | | | - Andrew J. S. Knox
- The University of Edinburgh, School of Biological Sciences (CSE) and School of Biomedical Sciences (CMVM), CH Waddington Building, 3.07, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JD, U.K
| | | | | | | | - Eric L. Singer
- Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037
| | - Larry Gerace
- Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037
| | - Manfred Auer
- The University of Edinburgh, School of Biological Sciences (CSE) and School of Biomedical Sciences (CMVM), CH Waddington Building, 3.07, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JD, U.K
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43
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Xu D, Farmer A, Chook YM. Recognition of nuclear targeting signals by Karyopherin-β proteins. Curr Opin Struct Biol 2010; 20:782-90. [PMID: 20951026 DOI: 10.1016/j.sbi.2010.09.008] [Citation(s) in RCA: 171] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 09/10/2010] [Accepted: 09/15/2010] [Indexed: 12/22/2022]
Abstract
The Karyopherin-β family of nuclear transport factors mediates the majority of nucleocytoplasmic transport. Although each of the 19 Karyopherin-βs transports unique sets of cargos, only three classes of nuclear localization and export signals, or NLSs and NESs, have been characterized. The short basic classical-NLS was first discovered in the 1980s and their karyopherin-bound structures were first reported more than 10 years ago. More recently, structural and biophysical studies of Karyopherin-β2-cargo complexes led to definition of the complex and diverse PY-NLS. Structural knowledge of the leucine-rich NES is finally available more than 10 years after the discovery of its recognition by the exportin CRM1. We review recent findings relating to how these three classes of nuclear targeting signals are recognized by their Karyopherin-β nuclear transport factors.
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Affiliation(s)
- Darui Xu
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9041, USA
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Kappel C, Zachariae U, Dölker N, Grubmüller H. An unusual hydrophobic core confers extreme flexibility to HEAT repeat proteins. Biophys J 2010; 99:1596-603. [PMID: 20816072 PMCID: PMC2931736 DOI: 10.1016/j.bpj.2010.06.032] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 05/10/2010] [Accepted: 06/07/2010] [Indexed: 01/16/2023] Open
Abstract
Alpha-solenoid proteins are suggested to constitute highly flexible macromolecules, whose structural variability and large surface area is instrumental in many important protein-protein binding processes. By equilibrium and nonequilibrium molecular dynamics simulations, we show that importin-beta, an archetypical alpha-solenoid, displays unprecedentedly large and fully reversible elasticity. Our stretching molecular dynamics simulations reveal full elasticity over up to twofold end-to-end extensions compared to its bound state. Despite the absence of any long-range intramolecular contacts, the protein can return to its equilibrium structure to within 3 A backbone RMSD after the release of mechanical stress. We find that this extreme degree of flexibility is based on an unusually flexible hydrophobic core that differs substantially from that of structurally similar but more rigid globular proteins. In that respect, the core of importin-beta resembles molten globules. The elastic behavior is dominated by nonpolar interactions between HEAT repeats, combined with conformational entropic effects. Our results suggest that alpha-solenoid structures such as importin-beta may bridge the molecular gap between completely structured and intrinsically disordered proteins.
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Affiliation(s)
| | | | | | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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Forwood JK, Lange A, Zachariae U, Marfori M, Preast C, Grubmüller H, Stewart M, Corbett AH, Kobe B. Quantitative Structural Analysis of Importin-β Flexibility: Paradigm for Solenoid Protein Structures. Structure 2010; 18:1171-83. [DOI: 10.1016/j.str.2010.06.015] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 05/04/2010] [Accepted: 06/01/2010] [Indexed: 12/24/2022]
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Selectivity mechanism of the nuclear pore complex characterized by single cargo tracking. Nature 2010; 467:600-3. [PMID: 20811366 PMCID: PMC2948059 DOI: 10.1038/nature09285] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Accepted: 06/10/2010] [Indexed: 01/10/2023]
Abstract
The nuclear pore complex (NPC) mediates all exchange between the cytoplasm and the nucleus. Small molecules can passively diffuse through the NPC, whereas larger cargos require transport receptors to translocate. How the NPC facilitates the translocation of transport receptor/cargo complexes remains unclear. To investigate this process, we tracked single protein-functionalized quantum dot cargos as they moved through human NPCs. Here we show that import proceeds by successive substeps comprising cargo capture, filtering and translocation, and release into the nucleus. Most quantum dots are rejected at one of these steps and return to the cytoplasm, including very large cargos that abort at a size-selective barrier. Cargo movement in the central channel is subdiffusive and cargos that can bind more transport receptors diffuse more freely. Without Ran GTPase, a critical regulator of transport directionality, cargos still explore the entire NPC, but have a markedly reduced probability of exit into the nucleus, suggesting that NPC entry and exit steps are not equivalent and that the pore is functionally asymmetric to importing cargos. The overall selectivity of the NPC seems to arise from the cumulative action of multiple reversible substeps and a final irreversible exit step.
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Molecular basis for the recognition of phosphorylated STAT1 by importin alpha5. J Mol Biol 2010; 402:83-100. [PMID: 20643137 DOI: 10.1016/j.jmb.2010.07.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/08/2010] [Accepted: 07/12/2010] [Indexed: 12/26/2022]
Abstract
Interferon-gamma stimulation triggers tyrosine phosphorylation of the transcription factor STAT1 at position 701, which is associated with switching from carrier-independent nucleocytoplasmic shuttling to carrier-mediated nuclear import. Unlike most substrates that carry a classical nuclear localization signal (NLS) and bind to importin alpha1, STAT1 possesses a nonclassical NLS recognized by the isoform importin alpha5. In the present study, we have analyzed the mechanisms by which importin alpha5 binds phosphorylated STAT1 (pSTAT1). We found that a homodimer of pSTAT1 is recognized by one equivalent of importin alpha5 with K(d)=191+/-20 nM. Whereas tyrosine phosphorylation at position 701 is essential to assemble a pSTAT1-importin alpha5 complex, the phosphate moiety is not a direct binding determinant for importin alpha5. In contrast to classical NLS substrates, pSTAT1 binding to importin alpha5 is not displaced by the N-terminal importin beta binding domain and requires the importin alpha5 C-terminal acidic tail (505-EEDD-508). A local unfolding of importin alpha5 Armadillo (ARM) repeat 10 accompanies high-affinity binding to pSTAT1. This unfolding is mediated by a single conserved tyrosine at position 476 of importin alpha5, which is inserted between ARM repeat 10 helices H1-H2-H3, thereby preventing intramolecular helical stacking essential to stabilize the folding conformation of ARM 10. Introducing a glycine at this position, as in importin alpha1, disrupts high-affinity binding to pSTAT1, suggesting that pSTAT1 recognition is dependent on the intrinsic flexibility of ARM 10. Using the quantitative stoichiometry and binding data presented in this article, together with mutational information available in the literature, we propose that importin alpha5 binds between two STAT1 monomers, with two major binding determinants in the SH2 and DNA binding domains. In vitro, this model is supported by the observation that a 38-mer DNA oligonucleotide containing two tandem cfosM67 promoters can displace importin alpha5 from pSTAT1, suggesting a possible role for DNA in releasing activated STAT1 in the cell nucleus.
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Bhardwaj A, Cingolani G. Conformational selection in the recognition of the snurportin importin beta binding domain by importin beta. Biochemistry 2010; 49:5042-7. [PMID: 20476751 DOI: 10.1021/bi100292y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structural flexibility of beta-karyopherins is critical to mediate the interaction with transport substrates, nucleoporins, and the GTPase Ran. In this paper, we provide structural evidence that the molecular recognition of the transport adaptor snurportin by importin beta follows the population selection mechanism. We have captured two drastically different conformations of importin beta bound to the snurportin importin beta binding domain trapped in the same crystallographic asymmetric unit. We propose the population selection may be a general mechanism used by beta-karyopherins to recognize transport substrates.
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Affiliation(s)
- Anshul Bhardwaj
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, Pennsylvania 19107, USA
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Kühn-Hölsken E, Lenz C, Dickmanns A, Hsiao HH, Richter FM, Kastner B, Ficner R, Urlaub H. Mapping the binding site of snurportin 1 on native U1 snRNP by cross-linking and mass spectrometry. Nucleic Acids Res 2010; 38:5581-93. [PMID: 20421206 PMCID: PMC2938196 DOI: 10.1093/nar/gkq272] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mass spectrometry allows the elucidation of molecular details of the interaction domains of the individual components in macromolecular complexes subsequent to cross-linking of the individual components. Here, we applied chemical and UV cross-linking combined with tandem mass-spectrometric analysis to identify contact sites of the nuclear import adaptor snurportin 1 to the small ribonucleoprotein particle U1 snRNP in addition to the known interaction of m3G cap and snurportin 1. We were able to define previously unknown sites of protein–protein and protein–RNA interactions on the molecular level within U1 snRNP. We show that snurportin 1 interacts with its central m3G-cap-binding domain with Sm proteins and with its extreme C-terminus with stem-loop III of U1 snRNA. The crosslinking data support the idea of a larger interaction area between snurportin 1 and U snRNPs and the contact sites identified prove useful for modeling the spatial arrangement of snurportin 1 domains when bound to U1 snRNP. Moreover, this suggests a functional nuclear import complex that assembles around the m3G cap and the Sm proteins only when the Sm proteins are bound and arranged in the proper orientation to the cognate Sm site in U snRNA.
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Affiliation(s)
- Eva Kühn-Hölsken
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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