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Mahtab Aslam Khan Khakwani M, Ji XY, Khattak S, Sun YC, Yao K, Zhang L. Targeting colorectal cancer at the level of nuclear pore complex. J Adv Res 2024:S2090-1232(24)00245-5. [PMID: 38876192 DOI: 10.1016/j.jare.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/23/2024] [Accepted: 06/07/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND Nuclear pore complexes (NPCs) are the architectures entrenched in nuclear envelop of a cell that regulate the nucleo-cytoplasmic transportation of materials such as proteins and RNAs for proper functioning of a cell. The appropriate localization of proteins and RNAs within the cell is essential for its normal functionality. For such a complex transportation of materials across the NPC, around 60 proteins are involved comprising nucleoporins, karyopherins and RAN system proteins that play a vital role in NPC's structure formation, cargo translocation across NPC, and cargoes' rapid directed transportation respectively. In various cancers, the structure and function of NPC is often exaggerated, following altered expressions of its nucleoporins and karyopherins, affecting other proteins of associated signaling pathways. Some inhibitors of karyopherins at present have potential to regulate the altered level/expression of these karyopherin molecules. AIM OF REVIEW This review summarizes the data from 1990 to 2023, mainly focusing on recent studies that illustrate the structure and function of NPC, the relationship and mechanisms of nucleoporins and karyopherins with colorectal cancer, as well as therapeutic values, in order to understand the pathology and underlying basis of colorectal cancer associated with NPC. This is the first review to our knowledge elucidating the detailed updated studies targeting colorectal cancer at NPC. The review also aims to target certain karyopherins, nups and their possible inhibitors and activators molecules as a therapeutic strategy. KEY SCIENTIFIC CONCEPTS OF REVIEW NPC structure provides understanding, how nucleoporins and karyopherins as key molecules are responsible for appropriate nucleocytoplasmic transportation. Many studies provide evidences describing the role of disrupted nucleoporins and karyopherins not only in CRC but also in other non-hematological and hematological malignancies. At present, some inhibitors of karyopherins have therapeutic potential for CRC, however development of more potent inhibitors may provide more effective therapeutic strategies for CRC in near future.
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Affiliation(s)
- Muhammad Mahtab Aslam Khan Khakwani
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China; Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medicine, Henan University, Kaifeng, Henan 475004, China
| | - Xin-Ying Ji
- Department of Oncology, Huaxian County Hospital, Huaxian, Henan Province 456400, China; Faculty of Basic Medical Subjects, Shu-Qing Medical College of Zhengzhou, Gong-Ming Rd, Mazhai Town, Erqi District, Zhengzhou, Henan 450064, China
| | - Saadullah Khattak
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China
| | - Ying-Chuan Sun
- Department of Internal Oncology (Section I), Xuchang Municipal Central Hospital, Xuchang, Henan 430000, China
| | - Kunhou Yao
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China.
| | - Lei Zhang
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China; Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medicine, Henan University, Kaifeng, Henan 475004, China.
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Skowicki M, Tarvirdipour S, Kraus M, Schoenenberger CA, Palivan CG. Nanoassemblies designed for efficient nuclear targeting. Adv Drug Deliv Rev 2024; 211:115354. [PMID: 38857762 DOI: 10.1016/j.addr.2024.115354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/23/2024] [Accepted: 06/04/2024] [Indexed: 06/12/2024]
Abstract
One of the key aspects of coping efficiently with complex pathological conditions is delivering the desired therapeutic compounds with precision in both space and time. Therefore, the focus on nuclear-targeted delivery systems has emerged as a promising strategy with high potential, particularly in gene therapy and cancer treatment. Here, we explore the design of supramolecular nanoassemblies as vehicles to deliver specific compounds to the nucleus, with the special focus on polymer and peptide-based carriers that expose nuclear localization signals. Such nanoassemblies aim at maximizing the concentration of genetic and therapeutic agents within the nucleus, thereby optimizing treatment outcomes while minimizing off-target effects. A complex scenario of conditions, including cellular uptake, endosomal escape, and nuclear translocation, requires fine tuning of the nanocarriers' properties. First, we introduce the principles of nuclear import and the role of nuclear pore complexes that reveal strategies for targeting nanosystems to the nucleus. Then, we provide an overview of cargoes that rely on nuclear localization for optimal activity as their integrity and accumulation are crucial parameters to consider when designing a suitable delivery system. Considering that they are in their early stages of research, we present various cargo-loaded peptide- and polymer nanoassemblies that promote nuclear targeting, emphasizing their potential to enhance therapeutic response. Finally, we briefly discuss further advancements for more precise and effective nuclear delivery.
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Affiliation(s)
- Michal Skowicki
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland; NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Shabnam Tarvirdipour
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland
| | - Manuel Kraus
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland
| | - Cora-Ann Schoenenberger
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland; NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, 4058 Basel, Switzerland.
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland; NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, 4058 Basel, Switzerland.
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Qian Z, Chen K, Yang L, Li C. Apoptosis-inducing factor 1 mediates Vibrio splendidus-induced coelomocyte apoptosis via importin β dependent nuclear translocation in Apostichopus japonicus. FISH & SHELLFISH IMMUNOLOGY 2024; 148:109491. [PMID: 38490346 DOI: 10.1016/j.fsi.2024.109491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 02/23/2024] [Accepted: 03/07/2024] [Indexed: 03/17/2024]
Abstract
As is well known, apoptosis is an important form of immune response and immune regulation, particularly playing a crucial role in combating microbial infections. Apoptosis-inducing factor 1 (AIF-1) is essential for apoptosis to induce chromatin condensation and DNA fragmentation via a caspase-independent pathway. The nuclear translocation of AIF-1 is a key step in apoptosis but the molecular mechanism is still unclear. In this study, the homologous gene of AIF-1, named AjAIF-1, was cloned and identified in Apostichopus japonicus. The mRNA expression of AjAIF-1 was significantly increased by 46.63-fold after Vibrio splendidus challenge. Silencing of AjAIF-1 was found to significantly inhibit coelomocyte apoptosis because the apoptosis rate of coelomocyte decreased by 0.62-fold lower compared with the control group. AjAIF-1 was able to promote coelomocyte apoptosis through nuclear translocation under the V. splendidus challenge. Moreover, AjAIF-1 and Ajimportin β were mainly co-localized around the nucleus in vivo and silencing Ajimportin β significantly inhibited the nuclear translocation of AjAIF-1 and suppressed coelomocyte apoptosis by 0.64-fold compared with control. In summary, nuclear translocation of AjAIF-1 will likely mediate coelomocyte apoptosis through an importin β-dependent pathway in sea cucumber.
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Affiliation(s)
- Zepeng Qian
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Kaiyu Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Lei Yang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China.
| | - Chenghua Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China.
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4
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Halbi G, Fayer I, Aranovich D, Gat S, Pavan MJ, Nachmias D, Sanchez DS, Brik A, Granek R, Bernheim-Groswasser A. Smart design of universally decorated nanoparticles for drug delivery applications driven by active transport. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:74. [PMID: 37653248 DOI: 10.1140/epje/s10189-023-00331-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 07/25/2023] [Indexed: 09/02/2023]
Abstract
Targeting the cell nucleus remains a challenge for drug delivery. Here, we present a universal platform for the smart design of nanoparticle (NP) decoration that is based on: (i) a spacer polymer, commonly biotin-polyethylene-glycol-thiol, whose grafting density and molecular weight can be tuned for optimized performance, and (ii) protein binding peptides, such as cell penetrating peptides (CPPs), cancer-targeting peptides, or nuclear localization signal (NLS) peptides, that are linked to the PEG free-end by universal chemistry. We manifested our platform with two different bromo-acetamide (Br-Ac) modified NLSs. We used cell extract-based and live cell assays to demonstrate the recruitment of dynein motor proteins, which drive the NP active transport toward the nucleus, and the enhancement of cellular and nuclear entry, manifesting the properties of NLS as a CPP. Our control of the NP decoration scheme, and the modularity of our platform, carry great advantages for nano-carrier design for drug delivery applications.
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Affiliation(s)
- Gal Halbi
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Itay Fayer
- The Stella and Avram Goren-Goldstein Department of Biotechnology Engineering Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Dina Aranovich
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Shachar Gat
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Mariela J Pavan
- The Ilse Katz Institute for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Dikla Nachmias
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Daniel Sevilla Sanchez
- The Ilse Katz Institute for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Ashraf Brik
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, 3200008, Haifa, Israel
| | - Rony Granek
- The Stella and Avram Goren-Goldstein Department of Biotechnology Engineering Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
- The Ilse Katz Institute for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel
| | - Anne Bernheim-Groswasser
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel.
- The Ilse Katz Institute for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, 84105, Beer Sheva, Israel.
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Li W, Zhao G, Jiao Z, Xiang C, Liang Y, Huang W, Nie P, Huang B. Nuclear import of IRF11 via the importin α/β pathway is essential for its antiviral activity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 141:104649. [PMID: 36716904 DOI: 10.1016/j.dci.2023.104649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Interferon regulatory factor 11 (IRF11), an intriguing IRF member found only in fish species, has recently been shown to have antiviral properties that are dependent on its nuclear entry and DNA binding affinity. However, the mechanisms by which IRF11 enters the nucleus are unknown. In the present study, we found orthologs of IRF11 in lamprey and lancelet species by combining positional, phylogenetic and structural comparison data, showing that this gene has an ancient origin. The IRF11 gene (AjIRF11) from the Japanese eel, Anguilla japonica, was subsequently characterized, and it was found that AjIRF11 has antiviral activities against spring viremia of carp virus (SVCV), which are accomplished by regulating the production of type I IFN and IFN-stimulated genes. In addition to its known DNA binding residues in the α3 helix, two residues in Loop 1, His40 and Trp46, are also involved in DNA binding and activation of the IFN promoter. Using immunofluorescence microscopy and site-directed mutagenesis analysis, we confirmed that full nuclear localization of AjIRF11 requires the bipartite nuclear localization sequence (NLS) spanning residues 75 to 101, as well as the monopartite NLS situated between residues 119 and 122. Coimmunoprecipitation assays confirmed that AjIRF11 interacts with importin α via its NLSs and can also bind to importin β directly, implying that IRF11 can be imported to the nucleus by one or more transport receptors.
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Affiliation(s)
- Wenxing Li
- Fisheries College, Jimei University, Xiamen, 361021, China
| | - Gejie Zhao
- Fisheries College, Jimei University, Xiamen, 361021, China
| | - Zhiyuan Jiao
- Fisheries College, Jimei University, Xiamen, 361021, China
| | - Chao Xiang
- Fisheries College, Jimei University, Xiamen, 361021, China
| | - Ying Liang
- Fisheries College, Jimei University, Xiamen, 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, China
| | - Wenshu Huang
- Fisheries College, Jimei University, Xiamen, 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, China
| | - Pin Nie
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, 266237, China; School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China.
| | - Bei Huang
- Fisheries College, Jimei University, Xiamen, 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, China.
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Jin L, Zhang G, Yang G, Dong J. Identification of the Karyopherin Superfamily in Maize and Its Functional Cues in Plant Development. Int J Mol Sci 2022; 23:ijms232214103. [PMID: 36430578 PMCID: PMC9699179 DOI: 10.3390/ijms232214103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/06/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
Appropriate nucleo-cytoplasmic partitioning of proteins is a vital regulatory mechanism in phytohormone signaling and plant development. However, how this is achieved remains incompletely understood. The Karyopherin (KAP) superfamily is critical for separating the biological processes in the nucleus from those in the cytoplasm. The KAP superfamily is divided into Importin α (IMPα) and Importin β (IMPβ) families and includes the core components in mediating nucleocytoplasmic transport. Recent reports suggest the KAPs play crucial regulatory roles in Arabidopsis development and stress response by regulating the nucleo-cytoplasmic transport of members in hormone signaling. However, the KAP members and their associated molecular mechanisms are still poorly understood in maize. Therefore, we first identified seven IMPα and twenty-seven IMPβ genes in the maize genome and described their evolution traits and the recognition rules for substrates with nuclear localization signals (NLSs) or nuclear export signals (NESs) in plants. Next, we searched for the protein interaction partners of the ZmKAPs and selected the ones with Arabidopsis orthologs functioning in auxin biosynthesis, transport, and signaling to predict their potential function. Finally, we found that several ZmKAPs share similar expression patterns with their interacting proteins, implying their function in root development. Overall, this article focuses on the Karyopherin superfamily in maize and starts with this entry point by systematically comprehending the KAP-mediated nucleo-cytoplasmic transport process in plants, and then predicts the function of the ZmKAPs during maize development, with a perspective on a closely associated regulatory mechanism between the nucleo-cytoplasmic transport and the phytohormone network.
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Affiliation(s)
- Lu Jin
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Guobin Zhang
- College of Agronomy, Shandong Agricultural University, Taian 271018, China
| | - Guixiao Yang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Jiaqiang Dong
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
- Correspondence:
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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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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: 104] [Impact Index Per Article: 52.0] [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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Halbi G, Fayer I, Aranovich D, Gat S, Bar S, Erukhimovitch V, Granek R, Bernheim-Groswasser A. Nano-Particles Carried by Multiple Dynein Motors Self-Regulate Their Number of Actively Participating Motors. Int J Mol Sci 2021; 22:ijms22168893. [PMID: 34445598 PMCID: PMC8396316 DOI: 10.3390/ijms22168893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 12/13/2022] Open
Abstract
Intra-cellular active transport by native cargos is ubiquitous. We investigate the motion of spherical nano-particles (NPs) grafted with flexible polymers that end with a nuclear localization signal peptide. This peptide allows the recruitment of several mammalian dynein motors from cytoplasmic extracts. To determine how motor–motor interactions influenced motility on the single microtubule level, we conducted bead-motility assays incorporating surface adsorbed microtubules and combined them with model simulations that were based on the properties of a single dynein. The experimental and simulation results revealed long time trajectories: when the number of NP-ligated motors Nm increased, run-times and run-lengths were enhanced and mean velocities were somewhat decreased. Moreover, the dependence of the velocity on run-time followed a universal curve, regardless of the system composition. Model simulations also demonstrated left- and right-handed helical motion and revealed self-regulation of the number of microtubule-bound, actively transporting dynein motors. This number was stochastic along trajectories and was distributed mainly between one, two, and three motors, regardless of Nm. We propose that this self-regulation allows our synthetic NPs to achieve persistent motion that is associated with major helicity. Such a helical motion might affect obstacle bypassing, which can influence active transport efficiency when facing the crowded environment of the cell.
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Affiliation(s)
- Gal Halbi
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (G.H.); (D.A.); (S.G.); (S.B.); (V.E.)
| | - Itay Fayer
- The Stella and Avram Goren-Goldstein Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel;
| | - Dina Aranovich
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (G.H.); (D.A.); (S.G.); (S.B.); (V.E.)
| | - Shachar Gat
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (G.H.); (D.A.); (S.G.); (S.B.); (V.E.)
| | - Shay Bar
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (G.H.); (D.A.); (S.G.); (S.B.); (V.E.)
| | - Vitaly Erukhimovitch
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (G.H.); (D.A.); (S.G.); (S.B.); (V.E.)
| | - Rony Granek
- The Stella and Avram Goren-Goldstein Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel;
- The Ilse Katz Institute for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Correspondence: (R.G.); (A.B.-G.)
| | - Anne Bernheim-Groswasser
- The Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (G.H.); (D.A.); (S.G.); (S.B.); (V.E.)
- The Ilse Katz Institute for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Correspondence: (R.G.); (A.B.-G.)
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10
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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] [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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Adenovirus Terminal Protein Contains a Bipartite Nuclear Localisation Signal Essential for Its Import into the Nucleus. Int J Mol Sci 2021; 22:ijms22073310. [PMID: 33804953 PMCID: PMC8036708 DOI: 10.3390/ijms22073310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 01/22/2023] Open
Abstract
Adenoviruses contain dsDNA covalently linked to a terminal protein (TP) at the 5′end. TP plays a pivotal role in replication and long-lasting infectivity. TP has been reported to contain a nuclear localisation signal (NLS) that facilitates its import into the nucleus. We studied the potential NLS motifs within TP using molecular and cellular biology techniques to identify the motifs needed for optimum nuclear import. We used confocal imaging microscopy to monitor the localisation and nuclear association of GFP fusion proteins. We identified two nuclear localisation signals, PV(R)6VP and MRRRR, that are essential for fully efficient TP nuclear entry in transfected cells. To study TP–host interactions further, we expressed TP in Escherichia coli (E. coli). Nuclear uptake of purified protein was determined in digitonin-permeabilised cells. The data confirmed that nuclear uptake of TP requires active transport using energy and shuttling factors. This mechanism of nuclear transport was confirmed when expressed TP was microinjected into living cells. Finally, we uncovered the nature of TP binding to host nuclear shuttling proteins, revealing selective binding to Imp β, and a complex of Imp α/β but not Imp α alone. TP translocation to the nucleus could be inhibited using selective inhibitors of importins. Our results show that the bipartite NLS is required for fully efficient TP entry into the nucleus and suggest that this translocation can be carried out by binding to Imp β or Imp α/β. This work forms the biochemical foundation for future work determining the involvement of TP in nuclear delivery of adenovirus DNA.
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12
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Edwards CM, Johnson RW. From Good to Bad: The Opposing Effects of PTHrP on Tumor Growth, Dormancy, and Metastasis Throughout Cancer Progression. Front Oncol 2021; 11:644303. [PMID: 33828987 PMCID: PMC8019909 DOI: 10.3389/fonc.2021.644303] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Parathyroid hormone related protein (PTHrP) is a multifaceted protein with several biologically active domains that regulate its many roles in normal physiology and human disease. PTHrP causes humoral hypercalcemia of malignancy (HHM) through its endocrine actions and tumor-induced bone destruction through its paracrine actions. PTHrP has more recently been investigated as a regulator of tumor dormancy owing to its roles in regulating tumor cell proliferation, apoptosis, and survival through autocrine/paracrine and intracrine signaling. Tumor expression of PTHrP in late stages of cancer progression has been shown to promote distant metastasis formation, especially in bone by promoting tumor-induced osteolysis and exit from dormancy. In contrast, PTHrP may protect against further tumor progression and improve patient survival in early disease stages. This review highlights current knowledge from preclinical and clinical studies examining the role of PTHrP in promoting tumor progression as well as skeletal and soft tissue metastasis, especially with regards to the protein as a regulator of tumor dormancy. The discussion will also provide perspectives on PTHrP as a prognostic factor and therapeutic target to inhibit tumor progression, prevent tumor recurrence, and improve patient survival.
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Affiliation(s)
- Courtney M Edwards
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Center for Bone Biology, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Rachelle W Johnson
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Center for Bone Biology, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
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13
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Chi RPA, van der Watt P, Wei W, Birrer MJ, Leaner VD. Inhibition of Kpnβ1 mediated nuclear import enhances cisplatin chemosensitivity in cervical cancer. BMC Cancer 2021; 21:106. [PMID: 33530952 PMCID: PMC7852134 DOI: 10.1186/s12885-021-07819-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 01/19/2021] [Indexed: 02/07/2023] Open
Abstract
Background Inhibition of nuclear import via Karyopherin beta 1 (Kpnβ1) shows potential as an anti-cancer approach. This study investigated the use of nuclear import inhibitor, INI-43, in combination with cisplatin. Methods Cervical cancer cells were pre-treated with INI-43 before treatment with cisplatin, and MTT cell viability and apoptosis assays performed. Activity and localisation of p53 and NFκB was determined after co-treatment of cells. Results Pre-treatment of cervical cancer cells with INI-43 at sublethal concentrations enhanced cisplatin sensitivity, evident through decreased cell viability and enhanced apoptosis. Kpnβ1 knock-down cells similarly displayed increased sensitivity to cisplatin. Combination index determination using the Chou-Talalay method revealed that INI-43 and cisplatin engaged in synergistic interactions. p53 was found to be involved in the cell death response to combination treatment as its inhibition abolished the enhanced cell death observed. INI-43 pre-treatment resulted in moderately stabilized p53 and induced p53 reporter activity, which translated to increased p21 and decreased Mcl-1 upon cisplatin combination treatment. Furthermore, cisplatin treatment led to nuclear import of NFκB, which was diminished upon pre-treatment with INI-43. NFκB reporter activity and expression of NFκB transcriptional targets, cyclin D1, c-Myc and XIAP, showed decreased levels after combination treatment compared to single cisplatin treatment and this associated with enhanced DNA damage. Conclusions Taken together, this study shows that INI-43 pre-treatment significantly enhances cisplatin sensitivity in cervical cancer cells, mediated through stabilization of p53 and decreased nuclear import of NFκB. Hence this study suggests the possible synergistic use of nuclear import inhibition and cisplatin to treat cervical cancer. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-021-07819-3.
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Affiliation(s)
- Ru-Pin Alicia Chi
- Division of Medical Biochemistry & Structural Biology, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa
| | - Pauline van der Watt
- Division of Medical Biochemistry & Structural Biology, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa
| | - Wei Wei
- Pfizer, Andover, MA, 01810, USA
| | - Michael J Birrer
- University of Arkansas Medical Sciences, D Winthrop P. Rockefeller Cancer Institute, Little Rock, AR, USA
| | - Virna D Leaner
- Division of Medical Biochemistry & Structural Biology, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
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14
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Chang CC, Hsia KC. More than a zip code: global modulation of cellular function by nuclear localization signals. FEBS J 2020; 288:5569-5585. [PMID: 33296547 DOI: 10.1111/febs.15659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Extensive structural and functional studies have been carried out in the field of nucleocytoplasmic transport. Nuclear transport factors, such as Importin-α/-β, recognize nuclear localization signals (NLSs) on cargo, and together with the small GTPase Ran, facilitate their nuclear localization. However, it is now emerging that binding of nuclear transport factors to NLSs not only mediates nuclear transport but also contributes to a variety of cellular functions in eukaryotes. Here, we describe recent advances that reveal how NLSs facilitate diverse cellular functions beyond nuclear transport activity. We review separately NLS-mediated regulatory mechanisms at different levels of biological organization, including (a) assembly of higher-order structures; (b) cellular organelle dynamics; and (c) modulation of cellular stress responses and viral infections. Finally, we provide mechanistic insights into how NLSs can regulate such a broad range of functions via their structural and biochemical properties.
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Affiliation(s)
- Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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15
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Neira JL, Rizzuti B, Jiménez-Alesanco A, Abián O, Velázquez-Campoy A, Iovanna JL. The Paralogue of the Intrinsically Disordered Nuclear Protein 1 Has a Nuclear Localization Sequence that Binds to Human Importin α3. Int J Mol Sci 2020; 21:ijms21197428. [PMID: 33050086 PMCID: PMC7583046 DOI: 10.3390/ijms21197428] [Citation(s) in RCA: 5] [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: 09/06/2020] [Revised: 09/28/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023] Open
Abstract
Numerous carrier proteins intervene in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, with several human isoforms; among them, importin α3 (Impα3) features a particularly high flexibility. The protein NUPR1L is an intrinsically disordered protein (IDP), evolved as a paralogue of nuclear protein 1 (NUPR1), which is involved in chromatin remodeling and DNA repair. It is predicted that NUPR1L has a nuclear localization sequence (NLS) from residues Arg51 to Gln74, in order to allow for nuclear translocation. We studied in this work the ability of intact NUPR1L to bind Impα3 and its depleted species, ∆Impα3, without the importin binding domain (IBB), using fluorescence, isothermal titration calorimetry (ITC), circular dichroism (CD), nuclear magnetic resonance (NMR), and molecular docking techniques. Furthermore, the binding of the peptide matching the isolated NLS region of NUPR1L (NLS-NUPR1L) was also studied using the same methods. Our results show that NUPR1L was bound to Imp α3 with a low micromolar affinity (~5 μM). Furthermore, a similar affinity value was observed for the binding of NLS-NUPR1L. These findings indicate that the NLS region, which was unfolded in isolation in solution, was essentially responsible for the binding of NUPR1L to both importin species. This result was also confirmed by our in silico modeling. The binding reaction of NLS-NUPR1L to ∆Impα3 showed a larger affinity (i.e., lower dissociation constant) compared with that of Impα3, confirming that the IBB could act as an auto-inhibition region of Impα3. Taken together, our findings pinpoint the theoretical predictions of the NLS region in NUPR1L and, more importantly, suggest that this IDP relies on an importin for its nuclear translocation.
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Affiliation(s)
- José L. Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche (Alicante), Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
- Correspondence: (J.L.N.); (J.L.I.); Tel.: +34-966-65-8475 (J.L.N.); +33(0)491-82-8803 (J.L.I.)
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, Cubo 31 C, Arcavacata di Rende, 87036 Cosenza, Italy;
| | - Ana Jiménez-Alesanco
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
| | - Olga Abián
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain
| | - Adrián Velázquez-Campoy
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; (A.J.-A.); (O.A.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Fundacion ARAID, Gobierno de Aragon, 50009 Zaragoza, Spain
| | - Juan L. Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13288 Marseille, France
- Correspondence: (J.L.N.); (J.L.I.); Tel.: +34-966-65-8475 (J.L.N.); +33(0)491-82-8803 (J.L.I.)
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16
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A Phosphorylation-Induced Switch in the Nuclear Localization Sequence of the Intrinsically Disordered NUPR1 Hampers Binding to Importin. Biomolecules 2020; 10:biom10091313. [PMID: 32933064 PMCID: PMC7565984 DOI: 10.3390/biom10091313] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022] Open
Abstract
Several carrier proteins are involved in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, of which there are several human isoforms; among them, importin α3 (Impα3) has a high flexibility. The protein NUPR1, a nuclear protein involved in the cell-stress response and cell cycle regulation, is an intrinsically disordered protein (IDP) that has a nuclear localization sequence (NLS) to allow for nuclear translocation. NUPR1 does localize through the whole cell. In this work, we studied the affinity of the isolated wild-type NLS region (residues 54–74) of NUPR1 towards Impα3 and several mutants of the NLS region by using several biophysical techniques and molecular docking approaches. The NLS region of NUPR1 interacted with Impα3, opening the way to model the nuclear translocation of disordered proteins. All the isolated NLS peptides were disordered. They bound to Impα3 with low micromolar affinity (1.7–27 μM). Binding was hampered by removal of either Lys65 or Lys69 residues, indicating that positive charges were important; furthermore, binding decreased when Thr68 was phosphorylated. The peptide phosphorylated at Thr68, as well as four phospho-mimetic peptides (all containing the Thr68Glu mutation), showed the presence of a sequential NN(i,i + 1) nuclear Overhauser effect (NOE) in the 2D-1H-NMR (two-dimensional–proton NMR) spectra, indicating the presence of turn-like conformations. Thus, the phosphorylation of Thr68 modulates the binding of NUPR1 to Impα3 by a conformational, entropy-driven switch from a random-coil conformation to a turn-like structure.
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17
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Díaz-García C, Hornos F, Giudici AM, Cámara-Artigas A, Luque-Ortega JR, Arbe A, Rizzuti B, Alfonso C, Forwood JK, Iovanna JL, Gómez J, Prieto M, Coutinho A, Neira JL. Human importin α3 and its N-terminal truncated form, without the importin-β-binding domain, are oligomeric species with a low conformational stability in solution. Biochim Biophys Acta Gen Subj 2020; 1864:129609. [PMID: 32234409 DOI: 10.1016/j.bbagen.2020.129609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/13/2020] [Accepted: 03/26/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Eukaryotic cells have a continuous transit of macromolecules between the cytoplasm and the nucleus. Several carrier proteins are involved in this transport. One of them is importin α, which must form a complex with importin β to accomplish its function, by domain-swapping its 60-residue-long N terminus. There are several human isoforms of importin α; among them, importin α3 has a particularly high flexibility. METHODS We studied the conformational stability of intact importin α3 (Impα3) and its truncated form, where the 64-residue-long, N-terminal importin-β-binding domain (IBB) has been removed (ΔImpα3), in a wide pH range, with several spectroscopic, biophysical, biochemical methods and with molecular dynamics (MD). RESULTS Both species acquired native-like structure between pH 7 and 10.0, where Impα3 was a dimer (with an apparent self-association constant of ~10 μM) and ΔImpα3 had a higher tendency to self-associate than the intact species. The acquisition of secondary, tertiary and quaternary structure, and the burial of hydrophobic patches, occurred concomitantly. Both proteins unfolded irreversibly at physiological pH, by using either temperature or chemical denaturants, through several partially folded intermediates. The MD simulations support the presence of these intermediates. CONCLUSIONS The thermal stability of Impα3 at physiological pH was very low, but was higher than that of ΔImpα3. Both proteins were stable in a narrow pH range, and they unfolded at physiological pH populating several intermediate species. GENERAL SIGNIFICANCE The low conformational stability explains the flexibility of Impα3, which is needed to carry out its recognition of complex cargo sequences.
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Affiliation(s)
- Clara Díaz-García
- iBB- Institute for Bioengineering and Bioscience, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
| | - Felipe Hornos
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain
| | | | - Ana Cámara-Artigas
- Departamento de Química y Física, Research Center CIAIMBITAL, Universidad de Almería- ceiA3, 04120 Almería, Spain
| | - Juan Román Luque-Ortega
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Arantxa Arbe
- Centro de Física de Materiales (CFM) (CSIC-UPV/EHU), Materials Physics Center (MPC), 20018 San Sebastián, Spain
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, Cubo 31 C, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Juan L Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13288 Marseille, France
| | - Javier Gómez
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain
| | - Manuel Prieto
- iBB- Institute for Bioengineering and Bioscience, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
| | - Ana Coutinho
- iBB- Institute for Bioengineering and Bioscience, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal; Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-004 Lisboa, Portugal
| | - José L Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain.
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18
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Abstract
The Ran pathway has a well-described function in nucleocytoplasmic transport, where active Ran dissociates importin/karyopherin-bound cargo containing a nuclear localization signal (NLS) in the nucleus. As cells enter mitosis, the nuclear envelope breaks down and a gradient of active Ran forms where levels are highest near chromatin. This gradient plays a crucial role in regulating mitotic spindle assembly, where active Ran binds to and releases importins from NLS-containing spindle assembly factors. An emerging theme is that the Ran gradient also regulates the actomyosin cortex for processes including polar body extrusion during meiosis, and cytokinesis. For these events, active Ran could play an inhibitory role, where importin-binding may help promote or stabilize a conformation or interaction that favours the recruitment and function of cortical regulators. For either spindle assembly or cortical polarity, the gradient of active Ran determines the extent of importin-binding, the effects of which could vary for different proteins.
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Affiliation(s)
- Imge Ozugergin
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, QC, Canada
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19
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A universal transportin protein drives stochastic choice of olfactory neurons via specific nuclear import of a sox-2-activating factor. Proc Natl Acad Sci U S A 2019; 116:25137-25146. [PMID: 31767767 DOI: 10.1073/pnas.1908168116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Stochastic neuronal cell fate choice involving notch-independent mechanisms is a poorly understood biological process. The Caenorhabditis elegans AWC olfactory neuron pair asymmetrically differentiates into the default AWCOFF and induced AWCON subtypes in a stochastic manner. Stochastic choice of the AWCON subtype is established using gap junctions and SLO BK potassium channels to repress a calcium-activated protein kinase pathway. However, it is unknown how the potassium channel-repressed calcium signaling is translated into the induction of the AWCON subtype. Here, we identify a detailed working mechanism of how the homeodomain-like transcription factor NSY-7, previously described as a repressor in the maintenance of AWC asymmetry, couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype through the identification of a unique imb-2 (transportin 1) allele. imb-2 loss-of-function mutants are not viable; however, we identify a viable imb-2 allele from an unbiased forward genetic screen that reveals a specific role of imb-2 in AWC olfactory neuron asymmetry. IMB-2 specifically drives nuclear import of NSY-7 within AWC neurons to transactivate the expression of the high mobility group (HMG)-box transcription factor SOX-2 for the specification of the AWCON subtype. This study provides mechanistic insight into how NSY-7 couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype. Our findings also provide structure-function insight into a conserved amino acid residue of transportins in brain development and suggest its dysfunction may lead to human neurological disorders.
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20
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Amaya Y, Nakai T. Localization and ER membrane insertion of parathyroid hormone-related protein analyzed without effects of reporter proteins. FEBS Lett 2019; 594:383-392. [PMID: 31471966 DOI: 10.1002/1873-3468.13592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 11/12/2022]
Abstract
Parathyroid hormone-related protein (PTHrP) is transported to both the secretory pathway and the nucleus/nucleolus by its dual targeting signals, that is, an N-terminal signal peptide and nuclear targeting signal. Curiously, reporter proteins such as enhanced green fluorescent protein strongly affect the localization of the fusion protein. Here, we report a novel methionine tag for 35 S-labelling added to the C-terminus of its prepro-form, which has no methionine and cysteine residue other than the initiation methionine that enables analyses of the molecular mechanism of its dual localization without the effects of the reporter proteins. Mutational analyses including insertion of a glycosylation site for the tagged PTHrP revealed that the evolutionarily conserved regions in the signal peptide and the pro-region facilitate the redirection of ppPTHrP from the secretory pathway to the nuclear targeting pathway.
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Affiliation(s)
- Yoshihiro Amaya
- Division of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Toshiki Nakai
- Radioisotope Research Center, Yokohama City University School of Medicine, Japan
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21
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Ho PWM, Chan AS, Pavlos NJ, Sims NA, Martin TJ. Brief exposure to full length parathyroid hormone-related protein (PTHrP) causes persistent generation of cyclic AMP through an endocytosis-dependent mechanism. Biochem Pharmacol 2019; 169:113627. [PMID: 31476292 DOI: 10.1016/j.bcp.2019.113627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/28/2019] [Indexed: 12/17/2022]
Abstract
Parathyroid hormone (PTH)-related protein (PTHrP) (gene name Pthlh) was discovered as the factor responsible for the humoral hypercalcemia of malignancy. It shares such sequence similarity with PTH in the amino-terminal region that the two are equally able to act through a single G protein-coupled receptor, PTH1R. A number of biological activities are ascribed to domains of PTHrP beyond the amino-terminal domain. PTH functions as a circulating hormone, but PTHrP is generated locally in many tissues including bone, where it acts as a paracrine factor on osteoblasts and osteocytes. The present study compares how PTH and PTHrP influence cyclic AMP (cAMP) formation through adenylyl cyclase, the first event in cell activation through PTH1R. Brief exposure to full length PTHrP(1-141) in several osteoblastic cell culture systems was followed by sustained adenylyl cyclase activity for more than an hour after ligand washout. This effect was dose-dependent and was not found with shorter PTHrP or PTH peptides even though they were fully able to activate adenylyl cyclase with acute treatment. The persistent activation response to PTHrP(1-141) was seen also with later events in the cAMP/PKA pathway, including persistent activation of CRE-luciferase and sustained regulation of several CREB-responsive mRNAs, up to 24 h after the initial exposure. Pharmacologic blockade of endocytosis prevented the persistent activation of cAMP and gene responses. We conclude that full length PTHrP, the likely local physiological effector in bone, differs in intracellular action to PTH by undergoing endosomal translocation to induce a prolonged adenylyl cyclase activation in its target cells.
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Affiliation(s)
- Patricia W M Ho
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia
| | - Audrey S Chan
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia; School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Nathan J Pavlos
- School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Natalie A Sims
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia; Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, Victoria 3065, Australia
| | - T John Martin
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia; Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, Victoria 3065, Australia.
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22
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Martin TJ, Johnson RW. Multiple actions of parathyroid hormone-related protein in breast cancer bone metastasis. Br J Pharmacol 2019; 178:1923-1935. [PMID: 31087800 DOI: 10.1111/bph.14709] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/16/2019] [Accepted: 04/23/2019] [Indexed: 12/14/2022] Open
Abstract
The sequence similarity within the amino-terminal regions of parathyroid hormone (PTH) and PTH-related protein (PTHrP) allows the two to share actions at a common site, the PTH1 receptor. A number of biological activities have been ascribed to actions of other domains within PTHrP. PTHrP production by late stage breast cancer has been shown to contribute to bone metastasis formation through promotion of osteoclast formation and bone resorption by action through PTH1 receptors. There is evidence also for a role for PTHrP early in breast cancer that is protective against tumour progression. No signalling pathway has been identified for this effect. PTHrP has also been identified as a factor promoting the emergence of breast cancer cells from dormancy in bone. In that case, PTHrP does not function through activation of PTH1 receptors, despite having very substantial effects on transcriptional activity of the breast cancer cells. This indicates actions of PTHrP that are non-canonical, that is, mediated through domains other than the amino-terminal. It is concluded that PTHrP has several distinct paracrine, autocrine, and intracrine actions in the course of breast cancer pathophysiology. Some are mediated through action at PTH1 receptors and others are controlled by other domains within PTHrP. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.
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Affiliation(s)
- T John Martin
- St Vincent's Institute of Medical Research, University of Melbourne, St Vincent's Health, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, St Vincent's Health, Melbourne, Victoria, Australia
| | - Rachelle W Johnson
- Department of Medicine, Division of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
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23
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Wong ETC, Gsponer J. Predicting Protein-Protein Interfaces that Bind Intrinsically Disordered Protein Regions. J Mol Biol 2019; 431:3157-3178. [PMID: 31207240 DOI: 10.1016/j.jmb.2019.06.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 12/18/2022]
Abstract
A long-standing goal in biology is the complete annotation of function and structure on all protein-protein interactions, a large fraction of which is mediated by intrinsically disordered protein regions (IDRs). However, knowledge derived from experimental structures of such protein complexes is disproportionately small due, in part, to challenges in studying interactions of IDRs. Here, we introduce IDRBind, a computational method that by combining gradient boosted trees and conditional random field models predicts binding sites of IDRs with performance approaching state-of-the-art globular interface predictions, making it suitable for proteome-wide applications. Although designed and trained with a focus on molecular recognition features, which are long interaction-mediating-elements in IDRs, IDRBind also predicts the binding sites of short peptides more accurately than existing specialized predictors. Consistent with IDRBind's specificity, a comparison of protein interface categories uncovered uniform trends in multiple physicochemical properties, positioning molecular recognition feature interfaces between peptide and globular interfaces.
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Affiliation(s)
- Eric T C Wong
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Jörg Gsponer
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
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24
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Frieling JS, Lynch CC. Proteolytic Regulation of Parathyroid Hormone-Related Protein: Functional Implications for Skeletal Malignancy. Int J Mol Sci 2019; 20:ijms20112814. [PMID: 31181800 PMCID: PMC6600663 DOI: 10.3390/ijms20112814] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 01/17/2023] Open
Abstract
Parathyroid hormone-related protein (PTHrP), with isoforms ranging from 139 to 173 amino acids, has long been implicated in the development and regulation of multiple tissues, including that of the skeleton, via paracrine and autocrine signaling. PTHrP is also known as a potent mediator of cancer-induced bone disease, contributing to a vicious cycle between tumor cells and the bone microenvironment that drives the formation and progression of metastatic lesions. The abundance of roles ascribed to PTHrP have largely been attributed to the N-terminal 1-36 amino acid region, however, activities for mid-region and C-terminal products as well as additional shorter N-terminal species have also been described. Studies of the protein sequence have indicated that PTHrP is susceptible to post-translational proteolytic cleavage by multiple classes of proteases with emerging evidence pointing to novel functional roles for these PTHrP products in regulating cell behavior in homeostatic and pathological contexts. As a consequence, PTHrP products are also being explored as potential biomarkers of disease. Taken together, our enhanced understanding of the post-translational regulation of PTHrP bioactivity could assist in developing new therapeutic approaches that can effectively treat skeletal malignancies.
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Affiliation(s)
- Jeremy S Frieling
- Tumor Biology Department, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA.
| | - Conor C Lynch
- Tumor Biology Department, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA.
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25
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Yang L, Yang Q, Wang M, Jia R, Chen S, Zhu D, Liu M, Wu Y, Zhao X, Zhang S, Liu Y, Yu Y, Zhang L, Chen X, Cheng A. Terminase Large Subunit Provides a New Drug Target for Herpesvirus Treatment. Viruses 2019; 11:v11030219. [PMID: 30841485 PMCID: PMC6466031 DOI: 10.3390/v11030219] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/23/2019] [Accepted: 02/27/2019] [Indexed: 12/26/2022] Open
Abstract
Herpesvirus infection is an orderly, regulated process. Among these viruses, the encapsidation of viral DNA is a noteworthy link; the entire process requires a powered motor that binds to viral DNA and carries it into the preformed capsid. Studies have shown that this power motor is a complex composed of a large subunit, a small subunit, and a third subunit, which are collectively known as terminase. The terminase large subunit is highly conserved in herpesvirus. It mainly includes two domains: the C-terminal nuclease domain, which cuts the viral concatemeric DNA into a monomeric genome, and the N-terminal ATPase domain, which hydrolyzes ATP to provide energy for the genome cutting and transfer activities. Because this process is not present in eukaryotic cells, it provides a reliable theoretical basis for the development of safe and effective anti-herpesvirus drugs. This article reviews the genetic characteristics, protein structure, and function of the herpesvirus terminase large subunit, as well as the antiviral drugs that target the terminase large subunit. We hope to provide a theoretical basis for the prevention and treatment of herpesvirus.
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Affiliation(s)
- Linlin Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Yunya Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Yanling Yu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Xiaoyue Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
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26
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Zhang R, Li J, Assaker G, Camirand A, Sabri S, Karaplis AC, Kremer R. Parathyroid Hormone-Related Protein (PTHrP): An Emerging Target in Cancer Progression and Metastasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1164:161-178. [DOI: 10.1007/978-3-030-22254-3_13] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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27
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Duan Z, Xu H, Ji X, Zhao J, Xu H, Hu Y, Deng S, Hu S, Liu X. Importin α5 negatively regulates importin β1-mediated nuclear import of Newcastle disease virus matrix protein and viral replication and pathogenicity in chicken fibroblasts. Virulence 2018. [PMID: 29532715 PMCID: PMC5955436 DOI: 10.1080/21505594.2018.1449507] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The matrix (M) protein of Newcastle disease virus (NDV) is demonstrated to localize in the nucleus via intrinsic nuclear localization signal (NLS), but cellular proteins involved in the nuclear import of NDV M protein and the role of M's nuclear localization in the replication and pathogenicity of NDV remain unclear. In this study, importin β1 was screened to interact with NDV M protein by yeast two-hybrid screening. This interaction was subsequently confirmed by co-immunoprecipitation and pull-down assays. In vitro binding studies indicated that the NLS region of M protein and the amino acids 336–433 of importin β1 that belonged to the RanGTP binding region were important for binding. Importantly, a recombinant virus with M/NLS mutation resulted in a pathotype change of NDV and attenuated viral replication and pathogenicity in chicken fibroblasts and SPF chickens. In agreement with the binding data, nuclear import of NDV M protein in digitonin-permeabilized HeLa cells required both importin β1 and RanGTP. Interestingly, importin α5 was verified to interact with M protein through binding importin β1. However, importin β1 or importin α5 depletion by siRNA resulted in different results, which showed the obviously cytoplasmic or nuclear accumulation of M protein and the remarkably decreased or increased replication ability and pathogenicity of NDV in chicken fibroblasts, respectively. Our findings therefore demonstrate for the first time the nuclear import mechanism of NDV M protein and the negative regulation role of importin α5 in importin β1-mediated nuclear import of M protein and the replication and pathogenicity of a paramyxovirus.
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Affiliation(s)
- Zhiqiang Duan
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Haixu Xu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xinqin Ji
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Jiafu Zhao
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Houqiang Xu
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Yan Hu
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shanshan Deng
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shunlin Hu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xiufan Liu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
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28
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Baade I, Spillner C, Schmitt K, Valerius O, Kehlenbach RH. Extensive Identification and In-depth Validation of Importin 13 Cargoes. Mol Cell Proteomics 2018; 17:1337-1353. [PMID: 29666159 PMCID: PMC6030721 DOI: 10.1074/mcp.ra118.000623] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/09/2018] [Indexed: 11/06/2022] Open
Abstract
Importin 13 is a member of the importin β family of transport receptors. Unlike most family members, importin 13 mediates both, nuclear protein import and export. To search for novel importin 13 cargoes, we used stable isotope labeling of amino acids in cell culture (SILAC) and mass spectrometry. Using stringent criteria, we identified 255 importin 13 substrates, including the known cargoes Ubc9, Mago and eIF1A, and validate many of them as transport cargoes by extensive biochemical and cell biological characterization. Several novel cargoes can also be transported by the export receptor CRM1, demonstrating a clear redundancy in receptor choice. Using importin 13 mutants, we show that many of the novel substrates contact regions on the transport receptor that are not used by Ubc9, Mago or eIF1A. Together, this study significantly expands the repertoire of importin 13 cargoes and sets the basis for a more detailed characterization of this extremely versatile transport receptor.
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Affiliation(s)
- Imke Baade
- From the ‡Department of Molecular Biology, Faculty of Medicine, Göttingen Center of Biosciences (GZMB), Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Christiane Spillner
- From the ‡Department of Molecular Biology, Faculty of Medicine, Göttingen Center of Biosciences (GZMB), Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Kerstin Schmitt
- §Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, GZMB, Georg-August-University Göttingen, Grisebachstr 8, 37077 Göttingen, Germany
| | - Oliver Valerius
- §Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, GZMB, Georg-August-University Göttingen, Grisebachstr 8, 37077 Göttingen, Germany
| | - Ralph H Kehlenbach
- From the ‡Department of Molecular Biology, Faculty of Medicine, Göttingen Center of Biosciences (GZMB), Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany;
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29
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Lodhi IJ, Dean JM, He A, Park H, Tan M, Feng C, Song H, Hsu FF, Semenkovich CF. PexRAP Inhibits PRDM16-Mediated Thermogenic Gene Expression. Cell Rep 2018; 20:2766-2774. [PMID: 28930673 DOI: 10.1016/j.celrep.2017.08.077] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/14/2017] [Accepted: 08/23/2017] [Indexed: 10/18/2022] Open
Abstract
How the nuclear receptor PPARγ regulates the development of two functionally distinct types of adipose tissue, brown and white fat, as well as the browning of white fat, remains unclear. Our previous studies suggest that PexRAP, a peroxisomal lipid synthetic enzyme, regulates PPARγ signaling and white adipogenesis. Here, we show that PexRAP is an inhibitor of brown adipocyte gene expression. PexRAP inactivation promoted adipocyte browning, increased energy expenditure, and decreased adiposity. Identification of PexRAP-interacting proteins suggests that PexRAP function extends beyond its role as a lipid synthetic enzyme. Notably, PexRAP interacts with importin-β1, a nuclear import factor, and knockdown of PexRAP in adipocytes reduced the levels of nuclear phospholipids. PexRAP also interacts with PPARγ, as well as PRDM16, a critical transcriptional regulator of thermogenesis, and disrupts the PRDM16-PPARγ complex, providing a potential mechanism for PexRAP-mediated inhibition of adipocyte browning. These results identify PexRAP as an important regulator of adipose tissue remodeling.
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Affiliation(s)
- Irfan J Lodhi
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA.
| | - John M Dean
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Anyuan He
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Hongsuk Park
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Min Tan
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Chu Feng
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Haowei Song
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Fong-Fu Hsu
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Clay F Semenkovich
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, Saint Louis, MO 63110, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
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30
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Evans SM, Rodino KG, Adcox HE, Carlyon JA. Orientia tsutsugamushi uses two Ank effectors to modulate NF-κB p65 nuclear transport and inhibit NF-κB transcriptional activation. PLoS Pathog 2018; 14:e1007023. [PMID: 29734393 PMCID: PMC5957444 DOI: 10.1371/journal.ppat.1007023] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/17/2018] [Accepted: 04/11/2018] [Indexed: 01/05/2023] Open
Abstract
Orientia tsutsugamushi causes scrub typhus, a potentially fatal infection that threatens over one billion people. Nuclear translocation of the transcription factor, NF-κB, is the central initiating cellular event in the antimicrobial response. Here, we report that NF-κB p65 nuclear accumulation and NF-κB-dependent transcription are inhibited in O. tsutsugamushi infected HeLa cells and/or primary macrophages, even in the presence of TNFα. The bacterium modulates p65 subcellular localization by neither degrading it nor inhibiting IκBα degradation. Rather, it exploits host exportin 1 to mediate p65 nuclear export, as this phenomenon is leptomycin B-sensitive. O. tsutsugamushi antagonizes NF-κB-activated transcription even when exportin 1 is inhibited and NF-κB consequently remains in the nucleus. Two ankyrin repeat-containing effectors (Anks), Ank1 and Ank6, each of which possess a C-terminal F-box and exhibit 58.5% amino acid identity, are linked to the pathogen's ability to modulate NF-κB. When ectopically expressed, both translocate to the nucleus, abrogate NF-κB-activated transcription in an exportin 1-independent manner, and pronouncedly reduce TNFα-induced p65 nuclear levels by exportin 1-dependent means. Flag-tagged Ank 1 and Ank6 co-immunoprecipitate p65 and exportin 1. Both also bind importin β1, a host protein that is essential for the classical nuclear import pathway. Importazole, which blocks importin β1 activity, abrogates Ank1 and Ank6 nuclear translocation. The Ank1 and Ank6 regions that bind importin β1 also mediate their transport into the nucleus. Yet, these regions are distinct from those that bind p65/exportin 1. The Ank1 and Ank6 F-box and the region that lies between it and the ankyrin repeat domain are essential for blocking p65 nuclear accumulation. These data reveal a novel mechanism by which O. tsutsugamushi modulates the activity and nuclear transport of NF-κB p65 and identify the first microbial proteins that co-opt both importin β1 and exportin 1 to antagonize a critical arm of the antimicrobial response.
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Affiliation(s)
- Sean M. Evans
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Kyle G. Rodino
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Haley E. Adcox
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Jason A. Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
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31
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Cutler AA, Jackson JB, Corbett AH, Pavlath GK. Non-equivalence of nuclear import among nuclei in multinucleated skeletal muscle cells. J Cell Sci 2018; 131:jcs.207670. [PMID: 29361530 DOI: 10.1242/jcs.207670] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 12/21/2017] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle is primarily composed of large myofibers containing thousands of post-mitotic nuclei distributed throughout a common cytoplasm. Protein production and localization in specialized myofiber regions is crucial for muscle function. Myonuclei differ in transcriptional activity and protein accumulation, but how these differences among nuclei sharing a cytoplasm are achieved is unknown. Regulated nuclear import of proteins is one potential mechanism for regulating transcription spatially and temporally in individual myonuclei. The best-characterized nuclear localization signal (NLS) in proteins is the classical NLS (cNLS), but many other NLS motifs exist. We examined cNLS and non-cNLS reporter protein import using multinucleated muscle cells generated in vitro, revealing that cNLS and non-cNLS nuclear import differs among nuclei in the same cell. Investigation of cNLS nuclear import rates in isolated myofibers ex vivo confirmed differences in nuclear import rates among myonuclei. Analyzing nuclear import throughout myogenesis revealed that cNLS and non-cNLS import varies during differentiation. Taken together, our results suggest that both spatial and temporal regulation of nuclear import pathways are important in muscle cell differentiation and protein regionalization in myofibers.
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Affiliation(s)
- Alicia A Cutler
- Department of Pharmacology, Emory University, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322, USA
| | | | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Grace K Pavlath
- Department of Pharmacology, Emory University, Atlanta, GA 30322, USA
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32
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Ha S, Jeong J, Oh J, Rhee S, Ham SW. A Small Organic Molecule Blocks EGFR Transport into the Nucleus by the Nonclassical Pathway Resulting in Repression of Cancer Invasion. Chembiochem 2017; 19:131-135. [PMID: 29159913 DOI: 10.1002/cbic.201700489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Indexed: 02/06/2023]
Abstract
In addition to the traditional epidermal growth factor receptor (EGFR) signaling pathways, nuclear EGFR has been shown to control multiple cellular functions, including cell proliferation and invasion. It has been reported that EGFR is transported into the nucleus after forming a complex with KPNA/KPNB1 or KPNB1. Herein, it is shown that EGFR can interact with both KP and KPNA, but EGF-activated EGFR mostly binds with KPNB1 through the pull-down assay. Also, a small organic molecule (1), an effective binder of KPNB1, inhibits the interaction between EGFR and KPNB1 in the nonclassical transport pathway, but not KPNA. Furthermore, treatment of cancer cells with 1 noticeably blocks the nuclear entry of EGFR, which results in significant suppression of invasion by lung cancer H1299 cells. These findings show that 1 is an effective inhibitor of EGFR/KPNB1 interactions in vitro, it may be used in cellular studies as a tool to determine the role of nuclear EGFR, and it is a drug candidate.
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Affiliation(s)
- Siyoung Ha
- Department of Chemistry, Chung-Ang University, 84 Heakseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Jangho Jeong
- Department of Life Science, Chung-Ang University, 84 Heakseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Jiwon Oh
- Department of Chemistry, Chung-Ang University, 84 Heakseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Sangmyung Rhee
- Department of Life Science, Chung-Ang University, 84 Heakseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Seung Wook Ham
- Department of Chemistry, Chung-Ang University, 84 Heakseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
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33
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Wu ZC, Zhang RH, Li YM, Shao DH, Chen H, Jiang SJ, Ma ZY, Wang X. C-terminal 20 residues of ORF3 protein of duck circovirus genotype 2 regulates the nuclear localization and inhibits apoptotic activity of ORF3 protein. Vet Microbiol 2017; 214:21-27. [PMID: 29408028 DOI: 10.1016/j.vetmic.2017.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/02/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
Abstract
Duck circovirus (DuCV) is divided into genotypes 1 and 2. The DuCV ORF3 protein is a newly identified viral protein with apoptotic activity. In this study, the differences in the gene sequences, subcellular localization, and apoptotic activities of the ORF3 proteins of DuCV genotypes 1 and 2 were analyzed. A T-to-A point mutation at nucleotide 236 (T236A) in the ORF3 gene sequence of DuCV genotype 1 was observed, which generates a premature stop codon (TAG) and resulted in a truncated ORF3 protein. The ORF3 protein of DuCV genotype 2 is 20 amino acids longer at its C-terminus than the truncated ORF3 protein of genotype 1. A variant monopartite-type nuclear localization signal (RRLRTCNCRACRTLK) was identified within the C-terminal region of the ORF3 protein of DuCV genotype 2, which is essential for the nuclear localization of the protein. The 20 C-terminal residues of the DuCV genotype 2 ORF3 protein also inhibits the apoptotic activity of the protein. Our findings provide insight into the biological and functional characteristics of the DuCV ORF3 protein.
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Affiliation(s)
- Zhuan-Chang Wu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China
| | - Rui-Hua Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, 271018, PR China
| | - Yu-Ming Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China
| | - Dong-Hua Shao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China
| | - Hua Chen
- College of Agriculture and Forestry Science, Linyi University, Shuangling Road, Linyi City, Shandong, 276005, PR China
| | - Shi-Jin Jiang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, 271018, PR China
| | - Zhi-Yong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China.
| | - Xin Wang
- College of Agriculture and Forestry Science, Linyi University, Shuangling Road, Linyi City, Shandong, 276005, PR China.
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34
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Sankhala RS, Lokareddy RK, Begum S, Pumroy RA, Gillilan RE, Cingolani G. Three-dimensional context rather than NLS amino acid sequence determines importin α subtype specificity for RCC1. Nat Commun 2017; 8:979. [PMID: 29042532 PMCID: PMC5645467 DOI: 10.1038/s41467-017-01057-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/15/2017] [Indexed: 12/27/2022] Open
Abstract
Active nuclear import of Ran exchange factor RCC1 is mediated by importin α3. This pathway is essential to generate a gradient of RanGTP on chromatin that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. Here we identify the mechanisms of importin α3 selectivity for RCC1. We find this isoform binds RCC1 with one order of magnitude higher affinity than the generic importin α1, although the two isoforms share an identical NLS-binding groove. Importin α3 uses its greater conformational flexibility to wedge the RCC1 β-propeller flanking the NLS against its lateral surface, preventing steric clashes with its Armadillo-core. Removing the β-propeller, or inserting a linker between NLS and β-propeller, disrupts specificity for importin α3, demonstrating the structural context rather than NLS sequence determines selectivity for isoform 3. We propose importin α3 evolved to recognize topologically complex NLSs that lie next to bulky domains or are masked by quaternary structures.Importin α3 facilitates the nuclear transport of the Ran guanine nucleotide exchange factor RCC1. Here the authors reveal the molecular basis for the selectivity of RCC1 for importin α3 vs the generic importin α1 and discuss the evolution of importin α isoforms.
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Affiliation(s)
- Rajeshwer S Sankhala
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Salma Begum
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Ruth A Pumroy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA.,Department of Biochemistry, University of Utah, 15N Medical Drive East, Salt Lake City, UT, 84112-5650, 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, 233 South 10th Street, Philadelphia, PA, 19107, USA. .,Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, Bari, 70126, Italy.
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35
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Duan Z, Zhao J, Xu H, Xu H, Ji X, Chen X, Xiong J. Characterization of the nuclear import pathway for BLM protein. Arch Biochem Biophys 2017; 634:57-68. [PMID: 29017749 DOI: 10.1016/j.abb.2017.09.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/18/2017] [Accepted: 09/29/2017] [Indexed: 01/13/2023]
Abstract
Numerous studies have shown that nuclear localization of BLM protein, a member of the RecQ helicases, mediated by nuclear localization signal (NLS) is critical for DNA recombination, replication and transcription, but the mechanism by which BLM protein is imported into the nucleus remains unknown. In this study, the nuclear import pathway for BLM was investigated. We found that nuclear import of BLM was inhibited by two dominant-negative mutants of importin β1 and NTF2/E42K, which lacks the ability to bind Ran and RanGDP, respectively, but was not inhibited by the Ran/Q69L, which is deficient in GTP hydrolysis. Further studies revealed that nuclear import of BLM was reconstituted using importin β1, RanGDP and NTF2 in digitonin-permeabilized HeLa cells. Moreover, BLM had direct binding to importin β1 through its NLS domain with the 14-16 HEAT repeats of importin β1. Furthermore, importin β1, Ran or NTF2 depletion by siRNA disrupted the accumulation of BLM protein in the nucleus. These results showed that BLM enters the nucleus via the importin β1, RanGDP and NTF2 dependent pathway, demonstrating for the first time the nuclear trafficking mechanism of a DNA helicase.
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Affiliation(s)
- Zhiqiang Duan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Jiafu Zhao
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Houqiang Xu
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China.
| | - Haixu Xu
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
| | - Xinqin Ji
- College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Xiang Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Jianming Xiong
- College of Animal Science, Guizhou University, Guiyang 550025, China
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36
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Zhu W, He X, Hua Y, Li Q, Wang J, Gan X. The E3 ubiquitin ligase WWP2 facilitates RUNX2 protein transactivation in a mono-ubiquitination manner during osteogenic differentiation. J Biol Chem 2017; 292:11178-11188. [PMID: 28500134 DOI: 10.1074/jbc.m116.772277] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/29/2017] [Indexed: 11/06/2022] Open
Abstract
Poly-ubiquitination-mediated RUNX2 degradation is an important cause of age- and inflammation-related bone loss. NEDD4 family E3 ubiquitin protein ligases are thought to be the major regulators of RUNX2 poly-ubiquitination. However, we observed a mono-ubiquitination of RUNX2 that was catalyzed by WWP2, a member of the NEDD4 family of E3 ubiquitin ligases. WWP2 has been reported to catalyze the mono-ubiquitination of Goosecoid in chondrocytes, facilitating craniofacial skeleton development. In this study, we found that osteogenic differentiation of mesenchymal stem cells promoted WWP2 expression and nuclear accumulation. Knockdown of Wwp2 in mesenchymal stem cells and osteoblasts led to significant deficiencies of osteogenesis, including decreased mineral deposition and down-regulation of osteogenic marker genes. Co-immunoprecipitation experiments showed the interaction of WWP2 with RUNX2 in vitro and in vivo Mono-ubiquitination by WWP2 leads to RUNX2 transactivation, as evidenced by the wild type of WWP2, but not its ubiquitin ligase-dead mutant, augmenting RUNX2-reponsive reporter activity. Moreover, deletion of WWP2-dependent mono-ubiquitination resulted in striking defects of RUNX2 osteoblastic activity. In addition, ectopic expression of the constitutively active type 1A bone morphogenetic protein receptor enhanced WWP2-dependent RUNX2 ubiquitination and transactivation, demonstrating a regulatory role of bone morphogenetic protein signaling in the WWP2-RUNX2 axis. Taken together, our results provide evidence that WWP2 serves as a positive regulator of osteogenesis by augmenting RUNX2 transactivation in a non-proteolytic mono-ubiquitination manner.
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Affiliation(s)
- Wei Zhu
- From the Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xinyu He
- From the Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Yue Hua
- From the Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Qian Li
- From the Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jiyong Wang
- From the Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xiaoqing Gan
- From the Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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37
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Salunke DM, Nair DT. Macromolecular structures: Quality assessment and biological interpretation. IUBMB Life 2017; 69:563-571. [DOI: 10.1002/iub.1640] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 04/25/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Dinakar M. Salunke
- International Centre for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg; New Delhi India
| | - Deepak T. Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster; 3rd Milestone, Faridabad-Gurgaon Expressway Faridabad Haryana India
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38
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Lång A, Eriksson J, Schink KO, Lång E, Blicher P, Połeć A, Brech A, Dalhus B, Bøe SO. Visualization of PML nuclear import complexes reveals FG-repeat nucleoporins at cargo retrieval sites. Nucleus 2017; 8:404-420. [PMID: 28402725 DOI: 10.1080/19491034.2017.1306161] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Selective nuclear import in eukaryotic cells involves sequential interactions between nuclear import receptors and phenylalanine-glycine (FG)-repeat nucleoporins. Traditionally, binding of cargoes to import receptors is perceived as a nuclear pore complex independent event, while interactions between import complexes and nucleoporins are thought to take place at the nuclear pores. However, studies have shown that nucleoporins are mobile and not static within the nuclear pores, suggesting that they may become engaged in nuclear import before nuclear pore entry. Here we have studied post-mitotic nuclear import of the tumor suppressor protein PML. Since this protein forms nuclear compartments called PML bodies that persist during mitosis, the assembly of putative PML import complexes can be visualized on the surface of these protein aggregates as the cell progress from an import inactive state in mitosis to an import active state in G1. We show that these post-mitotic cytoplasmic PML bodies incorporate a multitude of peripheral nucleoporins, but not scaffold or nuclear basket nucleoporins, in a manner that depends on FG-repeats, the KPNB1 import receptor, and the PML nuclear localization signal. The study suggests that nucleoporins have the ability to target certain nuclear cargo proteins in a nuclear pore-uncoupled state, before nuclear pore entry.
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Affiliation(s)
- Anna Lång
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.,b Institute of Clinical Medicine , University of Oslo , Oslo , Norway
| | - Jens Eriksson
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway
| | - Kay Oliver Schink
- c Department of Molecular Cell Biology, Institute for Cancer Research and Centre for Cancer Biomedicine , Oslo University Hospital , Oslo , Norway
| | - Emma Lång
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway
| | - Pernille Blicher
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway
| | - Anna Połeć
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway
| | - Andreas Brech
- c Department of Molecular Cell Biology, Institute for Cancer Research and Centre for Cancer Biomedicine , Oslo University Hospital , Oslo , Norway
| | - Bjørn Dalhus
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway
| | - Stig Ove Bøe
- a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway
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39
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Soniat M, Cağatay T, Chook YM. Recognition Elements in the Histone H3 and H4 Tails for Seven Different Importins. J Biol Chem 2016; 291:21171-21183. [PMID: 27528606 DOI: 10.1074/jbc.m116.730218] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Indexed: 12/12/2022] Open
Abstract
N-terminal tails of histones H3 and H4 are known to bind several different Importins to import the histones into the cell nucleus. However, it is not known what binding elements in the histone tails are recognized by the individual Importins. Biochemical studies of H3 and H4 tails binding to seven Importins, Impβ, Kapβ2, Imp4, Imp5, Imp7, Imp9, and Impα, show the H3 tail binding more tightly than the H4 tail. The H3 tail binds Kapβ2 and Imp5 with KD values of 77 and 57 nm, respectively, and binds the other five Importins more weakly. Mutagenic analysis shows H3 tail residues 11-27 to be the sole binding segment for Impβ, Kapβ2, and Imp4. However, Imp5, Imp7, Imp9, and Impα bind two separate elements in the H3 tail: the segment at residues 11-27 and an isoleucine-lysine nuclear localization signal (IK-NLS) motif at residues 35-40. The H4 tail also uses either one or two basic segments to bind the same set of Importins with a similar trend of relative affinities as the H3 tail, albeit at least 10-fold weaker. Of the many lysine residues in the H3 and H4 tails, only acetylation of the H3 Lys14 substantially decreased binding to several Importins. Lastly, we show that, in addition to the N-terminal tails, the histone fold domains of H3 and H4 and/or the histone chaperone Asf1b are important for Importin-histone recognition.
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Affiliation(s)
- Michael Soniat
- From the Department of Pharmacology, University of Texas Southwestern, Dallas, Texas 75390
| | - Tolga Cağatay
- From the Department of Pharmacology, University of Texas Southwestern, Dallas, Texas 75390
| | - Yuh Min Chook
- From the Department of Pharmacology, University of Texas Southwestern, Dallas, Texas 75390
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40
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Martin TJ. Parathyroid Hormone-Related Protein, Its Regulation of Cartilage and Bone Development, and Role in Treating Bone Diseases. Physiol Rev 2016; 96:831-71. [DOI: 10.1152/physrev.00031.2015] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although parathyroid hormone-related protein (PTHrP) was discovered as a cancer-derived hormone, it has been revealed as an important paracrine/autocrine regulator in many tissues, where its effects are context dependent. Thus its location and action in the vasculature explained decades-long observations that injection of PTH into animals rapidly lowered blood pressure by producing vasodilatation. Its roles have been specified in development and maturity in cartilage and bone as a crucial regulator of endochondral bone formation and bone remodeling, respectively. Although it shares actions with parathyroid hormone (PTH) through the use of their common receptor, PTHR1, PTHrP has other actions mediated by regions within the molecule beyond the amino-terminal sequence that resembles PTH, including the ability to promote placental transfer of calcium from mother to fetus. A striking feature of the physiology of PTHrP is that it possesses structural features that equip it to be transported in and out of the nucleus, and makes use of a specific nuclear import mechanism to do so. Evidence from mouse genetic experiments shows that PTHrP generated locally in bone is essential for normal bone remodeling. Whereas the main physiological function of PTH is the hormonal regulation of calcium metabolism, locally generated PTHrP is the important physiological mediator of bone remodeling postnatally. Thus the use of intermittent injection of PTH as an anabolic therapy for bone appears to be a pharmacological application of the physiological function of PTHrP. There is much current interest in the possibility of developing PTHrP analogs that might enhance the therapeutic anabolic effects.
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Affiliation(s)
- T. John Martin
- St Vincent's Institute of Medical Research, Department of Medicine, University of Melbourne, St Vincent's Hospital, Melbourne, Australia
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41
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Kim YH, Ha S, Kim J, Ham SW. Identification of KPNB1 as a Cellular Target of Aminothiazole Derivatives with Anticancer Activity. ChemMedChem 2016; 11:1406-9. [PMID: 27241026 DOI: 10.1002/cmdc.201600159] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/11/2016] [Indexed: 11/07/2022]
Abstract
We found that aminothiazole derivative (E)-N-(5-benzylthiazol-2-yl)-3-(furan-2-yl)acrylamide (1) has strong anticancer activity, and undertook proteomics approaches to identify the target protein of compound 1, importin β1 (KPNB1). A competitive binding assay using fluorescein-labeled 1 showed that 1 has strong binding affinity for KPNB1 (Kd : ∼20 nm). Furthermore, through western blotting assays for KPNB1, KPNA2, EGFR, ErbB2, and STAT3, we confirmed that 1 has inhibitory effects on the importin pathway. KPBN1 appears to be overexpressed in several cancer cells, and siRNA-induced inhibition of KPNB1 shows significant inhibition of cancer cell proliferation, while leaving non-cancerous cells unaffected. Therefore, compound 1 is a promising new lead for the development of KPNB1-targeted anticancer agents. Fluorescein-labeled 1 could be a useful quantitative probe for the development of novel KPNB1 inhibitors.
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Affiliation(s)
- Yong-Hak Kim
- Department, Catholic University of Daegu School of Medicine, 3056-6 Daemyeong 4-dong, Nam-gu, Daegu, 705-718, Republic of Korea
| | - Siyoung Ha
- Department of Chemistry, Chung-Ang University, 221 Heakseok-dong, Dongjak-gu, Seoul, 156-756, Republic of Korea
| | - Jungwon Kim
- Department of Chemistry, Chung-Ang University, 221 Heakseok-dong, Dongjak-gu, Seoul, 156-756, Republic of Korea
| | - Seung Wook Ham
- Department of Chemistry, Chung-Ang University, 221 Heakseok-dong, Dongjak-gu, Seoul, 156-756, Republic of Korea.
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42
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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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43
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Abstract
Nuclear pore complexes (NPCs) are indispensable for cell function and are at the center of several human diseases. NPCs provide access to the nucleus and regulate the transport of proteins and RNA across the nuclear envelope. They are aqueous channels generated from a complex network of evolutionarily conserved proteins known as nucleporins. In this Cell Science at a Glance article and the accompanying poster, we discuss how transport between the nucleoplasm and the cytoplasm is regulated, what we currently know about the structure of individual nucleoporins and the assembled NPC, and how the cell regulates assembly and disassembly of such a massive structure. Our aim is to provide a general overview on what we currently know about the nuclear pore and point out directions of research this area is heading to.
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44
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Sankhala RS, Lokareddy RK, Cingolani G. Divergent Evolution of Nuclear Localization Signal Sequences in Herpesvirus Terminase Subunits. J Biol Chem 2016; 291:11420-33. [PMID: 27033706 DOI: 10.1074/jbc.m116.724393] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 11/06/2022] Open
Abstract
The tripartite terminase complex of herpesviruses assembles in the cytoplasm of infected cells and exploits the host nuclear import machinery to gain access to the nucleus, where capsid assembly and genome-packaging occur. Here we analyzed the structure and conservation of nuclear localization signal (NLS) sequences previously identified in herpes simplex virus 1 (HSV-1) large terminase and human cytomegalovirus (HCMV) small terminase. We found a monopartite NLS at the N terminus of large terminase, flanking the ATPase domain, that is conserved only in α-herpesviruses. In contrast, small terminase exposes a classical NLS at the far C terminus of its helical structure that is conserved only in two genera of the β-subfamily and absent in α- and γ-herpesviruses. In addition, we predicted a classical NLS in the third terminase subunit that is partially conserved among herpesviruses. Bioinformatic analysis revealed that both location and potency of NLSs in terminase subunits evolved more rapidly than the rest of the amino acid sequence despite the selective pressure to keep terminase gene products active and localized in the nucleus. We propose that swapping NLSs among terminase subunits is a regulatory mechanism that allows different herpesviruses to regulate the kinetics of terminase nuclear import, reflecting a mechanism of virus:host adaptation.
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Affiliation(s)
- Rajeshwer S Sankhala
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and
| | - Ravi K Lokareddy
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and
| | - Gino Cingolani
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, 70126 Bari, Italy
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45
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Roggero VR, Zhang J, Parente LE, Doshi Y, Dziedzic RC, McGregor EL, Varjabedian AD, Schad SE, Bondzi C, Allison LA. Nuclear import of the thyroid hormone receptor α1 is mediated by importin 7, importin β1, and adaptor importin α1. Mol Cell Endocrinol 2016; 419:185-97. [PMID: 26525414 PMCID: PMC4684427 DOI: 10.1016/j.mce.2015.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/20/2015] [Accepted: 10/20/2015] [Indexed: 01/27/2023]
Abstract
The thyroid hormone receptor α1 (TRα1) is a nuclear receptor for thyroid hormone that shuttles rapidly between the nucleus and cytoplasm. Our prior studies showed that nuclear import of TRα1 is directed by two nuclear localization signals, one in the N-terminal A/B domain and the other in the hinge domain. Here, we showed using in vitro nuclear import assays that TRα1 nuclear localization is temperature and energy-dependent and can be reconstituted by the addition of cytosol. In HeLa cells expressing green fluorescent protein (GFP)-tagged TRα1, knockdown of importin 7, importin β1 and importin α1 by RNA interference, or treatment with an importin β1-specific inhibitor, significantly reduced nuclear localization of TRα1, while knockdown of other importins had no effect. Coimmunoprecipitation assays confirmed that TRα1 interacts with importin 7, as well as importin β1 and the adapter importin α1, suggesting that TRα1 trafficking into the nucleus is mediated by two distinct pathways.
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Affiliation(s)
- Vincent R Roggero
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Jibo Zhang
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Laura E Parente
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Yazdi Doshi
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Rose C Dziedzic
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Emma L McGregor
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Arev D Varjabedian
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Sara E Schad
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Cornelius Bondzi
- Department of Biological Sciences, Hampton University, Hampton, VA, 23668, USA
| | - Lizabeth A Allison
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA.
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46
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Lolodi O, Yamazaki H, Otsuka S, Kumeta M, Yoshimura SH. Dissecting in vivo steady-state dynamics of karyopherin-dependent nuclear transport. Mol Biol Cell 2015; 27:167-76. [PMID: 26538027 PMCID: PMC4694755 DOI: 10.1091/mbc.e15-08-0601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/27/2015] [Indexed: 11/11/2022] Open
Abstract
The steady-state dynamics of karyopherin-dependent nuclear transport in a living cell is examined. The kinetic model established by a number of experimentally obtained parameters reveals how each step of the transport system contributes to maintaining steady-state cargo gradient and fluxes across the nuclear envelope. Karyopherin-dependent molecular transport through the nuclear pore complex is maintained by constant recycling pathways of karyopherins coupled with the Ran-dependent cargo catch-and-release mechanism. Although many studies have revealed the bidirectional dynamics of karyopherins, the entire kinetics of the steady-state dynamics of karyopherin and cargo is still not fully understood. In this study, we used fluorescence recovery after photobleaching and fluorescence loss in photobleaching on live cells to provide convincing in vivo proof that karyopherin-mediated nucleocytoplasmic transport of cargoes is bidirectional. Continuous photobleaching of the cytoplasm of live cells expressing NLS cargoes led to progressive decrease of nuclear fluorescence signals. In addition, experimentally obtained kinetic parameters of karyopherin complexes were used to establish a kinetic model to explain the entire cargo import and export transport cycles facilitated by importin β. The results strongly indicate that constant shuttling of karyopherins, either free or bound to cargo, ensures proper balancing of nucleocytoplasmic distribution of cargoes and establishes effective regulation of cargo dynamics by RanGTP.
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Affiliation(s)
| | - Hiroya Yamazaki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Shotaro Otsuka
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Masahiro Kumeta
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Shige H Yoshimura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
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47
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Amaya Y, Nakai T, Miura S. Evolutionary well-conserved region in the signal peptide of parathyroid hormone-related protein is critical for its dual localization through the regulation of ER translocation. J Biochem 2015; 159:393-406. [PMID: 26538570 DOI: 10.1093/jb/mvv111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/29/2015] [Indexed: 01/02/2023] Open
Abstract
Parathyroid hormone-related protein (PTHrP) has two different targeting signals: an N-terminal signal peptide for the endoplasmic reticulum (ER) targeting and an internal nuclear localization signal. The protein not only functions as a secretory protein, but is also found in the nucleus and/or nucleolus under certain conditions. PTHrP signal peptide is less hydrophobic than most signal peptides mainly due to its evolutionarily well-conserved region (QQWS). The substitution of four tandem leucine residues for this conserved region resulted in a significant inhibition of the signal peptide cleavage. At the same time, proportion of nuclear and/or nucleolar localization decreased, probably due to tethering of the protein to the ER membrane by the uncleaved mutant signal peptide. Almost complete cleavage of the signal peptide accompanied by a lack of nuclear/nucleolar localization was achieved by combining the hydrophobic h-region and an optimized sequence of the cleavage site. In addition, mutational modifications of the distribution of charged residues in and around the signal peptide affect its cleavage and/or nuclear/nucleolar localization of the protein. These results indicate that the well-conserved region in the signal peptide plays an essential role in the dual localization of PTHrP through ER targeting and/or the membrane translocation.
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Affiliation(s)
- Yoshihiro Amaya
- Division of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan and
| | - Toshiki Nakai
- Radioisotope Research Center, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Satoshi Miura
- Radioisotope Research Center, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
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48
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Christie M, Chang CW, Róna G, Smith KM, Stewart AG, Takeda AAS, Fontes MRM, Stewart M, Vértessy BG, Forwood JK, Kobe B. Structural Biology and Regulation of Protein Import into the Nucleus. J Mol Biol 2015; 428:2060-90. [PMID: 26523678 DOI: 10.1016/j.jmb.2015.10.023] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/16/2015] [Accepted: 10/24/2015] [Indexed: 11/28/2022]
Abstract
Proteins are translated in the cytoplasm, but many need to access the nucleus to perform their functions. Understanding how these nuclear proteins are transported through the nuclear envelope and how the import processes are regulated is therefore an important aspect of understanding cell function. Structural biology has played a key role in understanding the molecular events during the transport processes and their regulation, including the recognition of nuclear targeting signals by the corresponding receptors. Here, we review the structural basis of the principal nuclear import pathways and the molecular basis of their regulation. The pathways involve transport factors that are members of the β-karyopherin family, which can bind cargo directly (e.g., importin-β, transportin-1, transportin-3, importin-13) or through adaptor proteins (e.g., importin-α, snurportin-1, symportin-1), as well as unrelated transport factors such as Hikeshi, involved in the transport of heat-shock proteins, and NTF2, involved in the transport of RanGDP. Solenoid proteins feature prominently in these pathways. Nuclear transport factors recognize nuclear targeting signals on the cargo proteins, including the classical nuclear localization signals, recognized by the adaptor importin-α, and the PY nuclear localization signals, recognized by transportin-1. Post-translational modifications, particularly phosphorylation, constitute key regulatory mechanisms operating in these pathways.
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Affiliation(s)
- Mary Christie
- The Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales Faculty of Medicine, Darlinghurst, NSW 2010, Australia
| | - Chiung-Wen Chang
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gergely Róna
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Kate M Smith
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
| | - Alastair G Stewart
- School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia
| | - Agnes A S Takeda
- Department of Physics and Biophysics, Institute of Biosciences, Universidade Estadual Paulista, Botucatu, São Paulo 18618-000, Brazil
| | - Marcos R M Fontes
- Department of Physics and Biophysics, Institute of Biosciences, Universidade Estadual Paulista, Botucatu, São Paulo 18618-000, Brazil
| | - Murray Stewart
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Beáta G Vértessy
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia.
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49
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Bin Hamid F, Kim J, Shin CG. Cellular and viral determinants of retroviral nuclear entry. Can J Microbiol 2015; 62:1-15. [PMID: 26553381 DOI: 10.1139/cjm-2015-0350] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retroviruses must integrate their cDNA into the host genome to generate proviruses. Viral DNA-protein complexes interact with cellular proteins and produce pre-integration complexes, which carry the viral genome and cross the nuclear pore channel to enter the nucleus and integrate viral DNA into host chromosomal DNA. If the reverse transcripts fail to integrate, linear or circular DNA species such as 1- and 2-long terminal repeats are generated. Such complexes encounter numerous cellular proteins in the cytoplasm, which restrict viral infection and protect the nucleus. To overcome host cell defenses, the pathogens have evolved several evasion strategies. Viral proteins often contain nuclear localization signals, allowing entry into the nucleus. Among more than 1000 proteins identified as required for HIV infection by RNA interference screening, karyopherins, cleavage and polyadenylation specific factor 6, and nucleoporins have been predominantly studied. This review discusses current opinions about the synergistic relationship between the viral and cellular factors involved in nuclear import, with focus on the unveiled mysteries of the host-pathogen interaction, and highlights novel approaches to pinpoint therapeutic targets.
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Affiliation(s)
- Faysal Bin Hamid
- Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea.,Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea
| | - Jinsun Kim
- Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea.,Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea
| | - Cha-Gyun Shin
- Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea.,Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea
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50
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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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