1
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Schirmer EC. Editorial: Editors' showcase 2022-2023: insights in nuclear organization and dynamics. Front Cell Dev Biol 2023; 11:1340745. [PMID: 38125874 PMCID: PMC10731362 DOI: 10.3389/fcell.2023.1340745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- Eric C. Schirmer
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
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2
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Xu P, Ma W, Liu J, Hu J, Cai W. Overexpression of a small GTP-binding protein Ran1 in Arabidopsis leads to promoted elongation growth and enhanced disease resistance against P. syringae DC3000. Plant J 2021; 108:977-991. [PMID: 34312926 DOI: 10.1111/tpj.15445] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Plants resist infection through an innate immune response, which is usually associated with slowing of growth. The molecular mechanisms underlying the trade-off between plant growth and defense remain unclear. The present study reveals that growth/defense trade-offs mediated by gibberellin (GA) and salicylic acid (SA) signaling pathways are uncoupled during constitutive overexpression of transgenic AtRAN1 and AtRAN1Q72L (active, GTP-locked form) Arabidopsis plants. It is well known that the small GTP-binding protein Ran (a Ras-related nuclear protein) functions in the nucleus-cytoplasmic transport of proteins. Although there is considerable evidence indicating that nuclear-cytoplasmic partitioning of specific proteins can participate in hormone signaling, the role of Ran-dependent nuclear transport in hormone signaling is not yet fully understood. In this report, we used a combination of genetic and molecular methods to reveal whether AtRAN1 is involved in both GA and SA signaling pathways. Constitutively overexpressed AtRAN1 promoted both elongation growth and the disease resistance response, whereas overexpression of AtRAN1Q72L in the atran2atran3 double mutant background clearly inhibited elongation growth and the defense response. Furthermore, we found that AtRAN1 coordinated plant growth and defense by promoting the stability of the DELLA protein RGA in the nucleus and by modulating NPR1 nuclear localization. Interestingly, genetically modified rice (Oryza sativa) overexpressing AtRAN1 exhibited increased plant height and yield per plant. Altogether, the ability to achieve growth/defense trade-offs through AtRAN1 overexpression provides an approach to maximizing crop yield to meet rising global food demands.
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Affiliation(s)
- Peipei Xu
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai, 200032, China
| | - Wei Ma
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai, 200032, China
| | - Jing Liu
- Microbiology and Immunity Department, The College of Medical Technology, Shanghai University of Medicine & Health Sciences, No. 279 Zhouzhu Road, Shanghai, 201318, China
| | - Jinbo Hu
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Weiming Cai
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai, 200032, China
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4
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Peggion C, Massimino ML, Stella R, Bortolotto R, Agostini J, Maldi A, Sartori G, Tonello F, Bertoli A, Lopreiato R. Nucleolin Rescues TDP-43 Toxicity in Yeast and Human Cell Models. Front Cell Neurosci 2021; 15:625665. [PMID: 33912014 PMCID: PMC8072491 DOI: 10.3389/fncel.2021.625665] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
TDP-43 is a nuclear protein involved in pivotal processes, extensively studied for its implication in neurodegenerative disorders. TDP-43 cytosolic inclusions are a common neuropathologic hallmark in amyotrophic lateral sclerosis (ALS) and related diseases, and it is now established that TDP-43 misfolding and aggregation play a key role in their etiopathology. TDP-43 neurotoxic mechanisms are not yet clarified, but the identification of proteins able to modulate TDP-43-mediated damage may be promising therapeutic targets for TDP-43 proteinopathies. Here we show by the use of refined yeast models that the nucleolar protein nucleolin (NCL) acts as a potent suppressor of TDP-43 toxicity, restoring cell viability. We provide evidence that NCL co-expression is able to alleviate TDP-43-induced damage also in human cells, further supporting its beneficial effects in a more consistent pathophysiological context. Presented data suggest that NCL could promote TDP-43 nuclear retention, reducing the formation of toxic cytosolic TDP-43 inclusions.
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Affiliation(s)
- Caterina Peggion
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Roberto Stella
- Food Safety Division, Department of Chemistry, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Raissa Bortolotto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Jessica Agostini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Arianna Maldi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Geppo Sartori
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Alessandro Bertoli
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,CNR - Neuroscience Institute, Padova, Italy.,Padova Neuroscience Center, University of Padova, Padova, Italy
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5
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Mboukou A, Rajendra V, Kleinova R, Tisné C, Jantsch MF, Barraud P. Transportin-1: A Nuclear Import Receptor with Moonlighting Functions. Front Mol Biosci 2021; 8:638149. [PMID: 33681296 PMCID: PMC7930572 DOI: 10.3389/fmolb.2021.638149] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 01/13/2021] [Indexed: 12/11/2022] Open
Abstract
Transportin-1 (Trn1), also known as karyopherin-β2 (Kapβ2), is probably the best-characterized nuclear import receptor of the karyopherin-β family after Importin-β, but certain aspects of its functions in cells are still puzzling or are just recently emerging. Since the initial identification of Trn1 as the nuclear import receptor of hnRNP A1 ∼25 years ago, several molecular and structural studies have unveiled and refined our understanding of Trn1-mediated nuclear import. In particular, the understanding at a molecular level of the NLS recognition by Trn1 made a decisive step forward with the identification of a new class of NLSs called PY-NLSs, which constitute the best-characterized substrates of Trn1. Besides PY-NLSs, many Trn1 cargoes harbour NLSs that do not resemble the archetypical PY-NLS, which complicates the global understanding of cargo recognition by Trn1. Although PY-NLS recognition is well established and supported by several structures, the recognition of non-PY-NLSs by Trn1 is far less understood, but recent reports have started to shed light on the recognition of this type of NLSs. Aside from its principal and long-established activity as a nuclear import receptor, Trn1 was shown more recently to moonlight outside nuclear import. Trn1 has for instance been caught in participating in virus uncoating, ciliary transport and in modulating the phase separation properties of aggregation-prone proteins. Here, we focus on the structural and functional aspects of Trn1-mediated nuclear import, as well as on the moonlighting activities of Trn1.
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Affiliation(s)
- Allegra Mboukou
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France
| | - Vinod Rajendra
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Renata Kleinova
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Carine Tisné
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France
| | - Michael F. Jantsch
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Pierre Barraud
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France
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6
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Abstract
Nuclear-cytoplasmic localization is an efficient way to regulate transcription factors and chromatin remodelers. Altering the location of existing protein pools also facilitates a more rapid response to changes in cell activity or extracellular signals. There are several examples of proteins that are regulated by nucleo-cytoplasmic shuttling, which are required for Drosophila neuroblast development. Disruption of the localization of homologs of these proteins has also been linked to several neurodegenerative disorders in humans. Drosophila has been used extensively to model the neurodegenerative disorders caused by aberrant nucleo-cytoplasmic localization. Here, we focus on the role of alternative nucleo-cytoplasmic protein localization in regulating proliferation and cell fate decisions in the Drosophila neuroblast and in neurodegenerative disorders. We also explore the analogous role of RNA binding proteins and mRNA localization in the context of regulation of nucleo-cytoplasmic localization during neural development and a role in neurodegenerative disorders.
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Affiliation(s)
- Sophie E Keegan
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sarah C Hughes
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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7
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Katahira J, Senokuchi K, Hieda M. Human THO maintains the stability of repetitive DNA. Genes Cells 2020; 25:334-342. [PMID: 32065701 DOI: 10.1111/gtc.12760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 01/31/2023]
Abstract
The evolutionarily conserved multiprotein complex THO/TREX is required for pre-mRNA processing, mRNA export and the maintenance of genome stability. In this study, we analyzed the genome-wide distribution of human THOC7, a component of human THO, by chromatin immunoprecipitation sequencing. The analysis revealed that human THOC7 occupies repetitive sequences, which include microsatellite repeats in genic and intergenic regions and telomeric repeats. The majority of the THOC7 ChIP peaks overlapped with those of the elongating form of RNA polymerase II and R-loops, indicating that THOC7 accumulates in transcriptionally active repeat regions. Knocking down THOC5, an RNA-binding component of human THO, by siRNA induced the accumulation of γH2AX in the repeat regions. We also observed an aberration in the telomeres in the THOC5-depleted condition. These results suggest that human THO restrains the transcription-associated instability of repeat regions in the human genome.
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Affiliation(s)
- Jun Katahira
- Laboratory of Cellular and Molecular Biology, Department of Veterinary Sciences, Osaka Prefecture University, Izumisano, Japan
| | - Kohei Senokuchi
- Laboratory of Cellular and Molecular Biology, Department of Veterinary Sciences, Osaka Prefecture University, Izumisano, Japan
| | - Miki Hieda
- Graduate School of Health Sciences, Ehime Prefectural University of Health Sciences, Iyo-gun, Japan
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8
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Viphakone N, Sudbery I, Griffith L, Heath CG, Sims D, Wilson SA. Co-transcriptional Loading of RNA Export Factors Shapes the Human Transcriptome. Mol Cell 2019; 75:310-323.e8. [PMID: 31104896 PMCID: PMC6675937 DOI: 10.1016/j.molcel.2019.04.034] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 02/25/2019] [Accepted: 04/29/2019] [Indexed: 11/29/2022]
Abstract
During gene expression, RNA export factors are mainly known for driving nucleo-cytoplasmic transport. While early studies suggested that the exon junction complex (EJC) provides a binding platform for them, subsequent work proposed that they are only recruited by the cap binding complex to the 5′ end of RNAs, as part of TREX. Using iCLIP, we show that the export receptor Nxf1 and two TREX subunits, Alyref and Chtop, are recruited to the whole mRNA co-transcriptionally via splicing but before 3′ end processing. Consequently, Alyref alters splicing decisions and Chtop regulates alternative polyadenylation. Alyref is recruited to the 5′ end of RNAs by CBC, and our data reveal subsequent binding to RNAs near EJCs. We demonstrate that eIF4A3 stimulates Alyref deposition not only on spliced RNAs close to EJC sites but also on single-exon transcripts. Our study reveals mechanistic insights into the co-transcriptional recruitment of mRNA export factors and how this shapes the human transcriptome. 5′ cap binding complex CBC acts as a transient landing pad for Alyref Alyref is deposited upstream of the exon-exon junction next to the EJC Alyref can be deposited on introns and regulate splicing Chtop is mainly deposited on 3′ UTRs and influences poly(A) site choices
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Affiliation(s)
- Nicolas Viphakone
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
| | - Ian Sudbery
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Llywelyn Griffith
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Catherine G Heath
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - David Sims
- MRC Computational Genomics Analysis and Training Programme (CGAT), MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, OX3 9DS UK
| | - Stuart A Wilson
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
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9
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Guan Y, Gao X, Tang Q, Huang L, Gao S, Yu S, Huang J, Li J, Zhou D, Zhang Y, Shi D, Liang D, Liu Y, Li L, Cui Y, Xu L, Chen YH. Nucleoporin 107 facilitates the nuclear export of Scn5a mRNA to regulate cardiac bioelectricity. J Cell Mol Med 2018; 23:1448-1457. [PMID: 30506890 PMCID: PMC6349201 DOI: 10.1111/jcmm.14051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/13/2018] [Accepted: 11/05/2018] [Indexed: 01/02/2023] Open
Abstract
Nucleoporins (Nups) are known to be functional in nucleo‐cytoplasmic transport, but the roles of nucleoporins in nonproliferating cells, such as cardiac myocytes, are still poorly understood. In this study, we report that Nup107 regulates cardiac bioelectricity by controlling the nucleo‐cytoplasmic trafficking of Scn5a mRNA. Overexpression of Nup107 induced the protein expression of Scn5a rather than that of other ion channels, with no effects of their mRNA levels. The analysis for the protein production demonstrated Nup107‐facilitated transport of Scn5a mRNA. Using RIP‐PCR and luciferase assay, we found that the 5′‐UTR of Scn5a mRNA was not involved in the interaction, whereas the spatial interaction between Nup107 protein and Scn5a mRNA was formed when Scn5a mRNA passing through the nuclear pore. Functionally, Nup107 overexpression in neonatal rat ventricle myocytes significantly increased the currents of Scn5a‐encoded INa channel. Moreover, the close correlation between Nup107 and Nav1.5 protein expression was observed in cardiomycytes and heart tissues subjected to hypoxia and ischaemic insults, suggesting a fast regulation of Nup107 on Nav1.5 channel in cardiac myocytes in a posttranscriptional manner. These findings may provide insights into the emergent control of cardiac electrophysiology through Nup‐mediated modulation of ion channels.
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Affiliation(s)
- Yi Guan
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Xueting Gao
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Qiuyu Tang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Lin Huang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Siyun Gao
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Shuai Yu
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Jiale Huang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jun Li
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Daizhan Zhou
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yangyang Zhang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dan Shi
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dandan Liang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi Liu
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Li Li
- Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Yingyu Cui
- Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Liang Xu
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi-Han Chen
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
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10
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Chen C, Masi RD, Lintermann R, Wirthmueller L. Nuclear Import of Arabidopsis Poly(ADP-Ribose) Polymerase 2 Is Mediated by Importin-α and a Nuclear Localization Sequence Located Between the Predicted SAP Domains. Front Plant Sci 2018; 9:1581. [PMID: 30455710 PMCID: PMC6230994 DOI: 10.3389/fpls.2018.01581] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 10/10/2018] [Indexed: 05/17/2023]
Abstract
Proteins of the Poly(ADP-Ribose) Polymerase (PARP) family modify target proteins by covalent attachment of ADP-ribose moieties onto amino acid side chains. In Arabidopsis, PARP proteins contribute to repair of DNA lesions and modulate plant responses to various abiotic and biotic stressors. Arabidopsis PARP1 and PARP2 are nuclear proteins and given that their molecular weights exceed the diffusion limit of nuclear pore complexes, an active import mechanism into the nucleus is likely. Here we use confocal microscopy of fluorescent protein-tagged Arabidopsis PARP2 and PARP2 deletion constructs in combination with site-directed mutagenesis to identify a nuclear localization sequence in PARP2 that is required for nuclear import. We report that in co-immunoprecipitation assays PARP2 interacts with several isoforms of the importin-α group of nuclear transport adapters and that PARP2 binding to IMPORTIN-α2 is mediated by the identified nuclear localization sequence. Our results demonstrate that PARP2 is a cargo protein of the canonical importin-α/β nuclear import pathway.
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Affiliation(s)
| | | | | | - Lennart Wirthmueller
- Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, Berlin, Germany
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11
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Zhou J, Dong D, Cheng R, Wang Y, Jiang S, Zhu Y, Fan L, Mao X, Gui Y, Li Z, Li X, Shi B. Aberrant expression of KPNA2 is associated with a poor prognosis and contributes to OCT4 nuclear transportation in bladder cancer. Oncotarget 2016; 7:72767-76. [PMID: 27611951 DOI: 10.18632/oncotarget.11889] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 08/31/2016] [Indexed: 11/25/2022] Open
Abstract
Recent studies show that Karyopherin alpha 2 (KPNA2) is up-regulated in quite a number of cancers and associated with poor prognosis. Here, we found that expression levels of KPNA2 and OCT4 are up-regulated in bladder cancer tissues and significantly associated with primary tumor stage and bladder cancer patients' poorer prognosis. Our data also showed decreased cell proliferation and migration rates of bladder cancer cell lines when the expression of KPNA2 and OCT4 was silenced. Meanwhile, cell apoptosis rate was increased. Furthermore, Co-IP and immunofluorescence assay showed the KPNA2 interacts with OCT4 and inhibits OCT4 nuclear transportation when KPNA2 was silenced. Thus, we confirmed that up-regulated KPNA2 and OCT4 expression is a common feature of bladder cancer that is correlated with increased aggressive tumor behavior. Also, we propose that KPNA2 regulates the process of OCT4 nuclear transportation in bladder cancer.
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12
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Yang Y, Wang W, Chu Z, Zhu JK, Zhang H. Roles of Nuclear Pores and Nucleo-cytoplasmic Trafficking in Plant Stress Responses. Front Plant Sci 2017; 8:574. [PMID: 28446921 PMCID: PMC5388774 DOI: 10.3389/fpls.2017.00574] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/30/2017] [Indexed: 05/29/2023]
Abstract
The nuclear pore complex (NPC) is a large protein complex that controls the exchange of components between the nucleus and the cytoplasm. In plants, the NPC family components play critical roles not only in essential growth and developmental processes, but also in plant responses to various environmental stress conditions. The involvement of NPC components in plant stress responses is mainly attributed to different mechanisms including control of mRNA/protein nucleo-cytoplasmic trafficking and transcriptional gene regulation. This mini review summarizes current knowledge of the NPC-mediated plant stress responses and provides an overview of the underlying molecular mechanisms.
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Affiliation(s)
- Yu Yang
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai, China
| | - Wei Wang
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical GardenShanghai, China
- Shanghai Chenshan Plant Science Research Center, Chinese Academy of SciencesShanghai, China
| | - Zhaoqing Chu
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical GardenShanghai, China
- Shanghai Chenshan Plant Science Research Center, Chinese Academy of SciencesShanghai, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai, China
- Department of Horticulture and Landscape Architecture, Purdue University, West LafayetteIN, USA
| | - Huiming Zhang
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai, China
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13
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Mettenleiter TC. Vesicular Nucleo-Cytoplasmic Transport-Herpesviruses as Pioneers in Cell Biology. Viruses 2016; 8:E266. [PMID: 27690080 DOI: 10.3390/v8100266] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 09/12/2016] [Accepted: 09/20/2016] [Indexed: 11/16/2022] Open
Abstract
Herpesviruses use a vesicle-mediated transfer of intranuclearly assembled nucleocapsids through the nuclear envelope (NE) for final maturation in the cytoplasm. The molecular basis for this novel vesicular nucleo-cytoplasmic transport is beginning to be elucidated in detail. The heterodimeric viral nuclear egress complex (NEC), conserved within the classical herpesviruses, mediates vesicle formation from the inner nuclear membrane (INM) by polymerization into a hexagonal lattice followed by fusion of the vesicle membrane with the outer nuclear membrane (ONM). Mechanisms of capsid inclusion as well as vesicle-membrane fusion, however, are largely unclear. Interestingly, a similar transport mechanism through the NE has been demonstrated in nuclear export of large ribonucleoprotein complexes during Drosophila neuromuscular junction formation, indicating a widespread presence of a novel concept of cellular nucleo-cytoplasmic transport.
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14
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Zahn R, Osmanović D, Ehret S, Araya Callis C, Frey S, Stewart M, You C, Görlich D, Hoogenboom BW, Richter RP. A physical model describing the interaction of nuclear transport receptors with FG nucleoporin domain assemblies. eLife 2016; 5. [PMID: 27058170 PMCID: PMC4874776 DOI: 10.7554/elife.14119] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 04/07/2016] [Indexed: 11/13/2022] Open
Abstract
The permeability barrier of nuclear pore complexes (NPCs) controls bulk nucleocytoplasmic exchange. It consists of nucleoporin domains rich in phenylalanine-glycine motifs (FG domains). As a bottom-up nanoscale model for the permeability barrier, we have used planar films produced with three different end-grafted FG domains, and quantitatively analyzed the binding of two different nuclear transport receptors (NTRs), NTF2 and Importin β, together with the concomitant film thickness changes. NTR binding caused only moderate changes in film thickness; the binding isotherms showed negative cooperativity and could all be mapped onto a single master curve. This universal NTR binding behavior - a key element for the transport selectivity of the NPC - was quantitatively reproduced by a physical model that treats FG domains as regular, flexible polymers, and NTRs as spherical colloids with a homogeneous surface, ignoring the detailed arrangement of interaction sites along FG domains and on the NTR surface.
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Affiliation(s)
- Raphael Zahn
- Biosurfaces Lab, CIC biomaGUNE, San Sebastian, Spain
| | - Dino Osmanović
- London Centre for Nanotechnology, University College London, London, United Kingdom.,Department of Physics and Astronomy, University College London, London, United Kingdom.,Department of Physics, Bar-Ilan University, Ramat Gan, Israel.,Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
| | - Severin Ehret
- Biosurfaces Lab, CIC biomaGUNE, San Sebastian, Spain
| | | | - Steffen Frey
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Murray Stewart
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Changjiang You
- Department of Biology, University of Osnabrück, Osnabrück, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, United Kingdom.,Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Ralf P Richter
- Biosurfaces Lab, CIC biomaGUNE, San Sebastian, Spain.,Laboratory of Interdisciplinary Physics, University Grenoble Alpes - CNRS, Grenoble, France.,Max-Planck-Institute for Intelligent Systems, Stuttgart, Germany
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15
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Kraft LJ, Manral P, Dowler J, Kenworthy AK. Nuclear LC3 Associates with Slowly Diffusing Complexes that Survey the Nucleolus. Traffic 2016; 17:369-99. [PMID: 26728248 PMCID: PMC4975375 DOI: 10.1111/tra.12372] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 12/31/2015] [Accepted: 12/31/2015] [Indexed: 12/22/2022]
Abstract
MAP1LC3B (microtubule-associated protein 1 light chain 3, LC3) is a key component of the autophagy pathway, contributing to both cargo selection and autophagosome formation in the cytoplasm. Emerging evidence suggests that nuclear forms of LC3 are also functionally important; however, the mechanisms that facilitate the nuclear targeting and trafficking of LC3 between the nucleus and cytoplasm under steady-state conditions are poorly understood. In this study, we examine how residues known to regulate the interactions between LC3 and other proteins or RNA (F52 L53, R68-R70 and G120) contribute to its nuclear targeting, nucleocytoplasmic transport and association with nucleoli and other nuclear components. We find that residues F52 L53 and R68-70, but not G120, regulate targeting of LC3 to the nucleus, its rates of nucleocytoplasmic transport and the apparent sizes of LC3-associated complexes in the nucleus inferred from fluorescence recovery after photobleaching (FRAP) measurements. We also show that LC3 is enriched in nucleoli and its triple arginine motif is especially important for nucleolar targeting. Finally, we identify a series of candidate nuclear LC3-interacting proteins using mass spectrometry, including MAP1B, tubulin and several 40S ribosomal proteins. These findings suggest LC3 is retained in the nucleus in association with high-molecular weight complexes that continuously scan the nucleolus.
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Affiliation(s)
- Lewis J Kraft
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA.,Current address: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Pallavi Manral
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jacob Dowler
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Anne K Kenworthy
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA.,Epithelial Biology Program, Vanderbilt University School of Medicine, Nashville, TN, USA
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16
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Cavazza T, Vernos I. The RanGTP Pathway: From Nucleo-Cytoplasmic Transport to Spindle Assembly and Beyond. Front Cell Dev Biol 2016; 3:82. [PMID: 26793706 PMCID: PMC4707252 DOI: 10.3389/fcell.2015.00082] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/07/2015] [Indexed: 01/03/2023] Open
Abstract
The small GTPase Ran regulates the interaction of transport receptors with a number of cellular cargo proteins. The high affinity binding of the GTP-bound form of Ran to import receptors promotes cargo release, whereas its binding to export receptors stabilizes their interaction with the cargo. This basic mechanism linked to the asymmetric distribution of the two nucleotide-bound forms of Ran between the nucleus and the cytoplasm generates a switch like mechanism controlling nucleo-cytoplasmic transport. Since 1999, we have known that after nuclear envelope breakdown (NEBD) Ran and the above transport receptors also provide a local control over the activity of factors driving spindle assembly and regulating other aspects of cell division. The identification and functional characterization of RanGTP mitotic targets is providing novel insights into mechanisms essential for cell division. Here we review our current knowledge on the RanGTP system and its regulation and we focus on the recent advances made through the characterization of its mitotic targets. We then briefly review the novel functions of the pathway that were recently described. Altogether, the RanGTP system has moonlighting functions exerting a spatial control over protein interactions that drive specific functions depending on the cellular context.
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Affiliation(s)
- Tommaso Cavazza
- Cell and Developmental Biology, Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Universitat Pompeu FabraBarcelona, Spain
| | - Isabelle Vernos
- Cell and Developmental Biology, Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Universitat Pompeu FabraBarcelona, Spain; Institució Catalana de Recerca I Estudis AvançatsBarcelona, Spain
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17
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Xu L, Pan L, Li J, Huang B, Feng J, Li C, Wang S, The E, Liu Y, Yuan T, Zhen L, Liang D, Liu Y, Li L, Cui Y, Jiang X, Peng L, Chen YH. Nucleoporin 35 regulates cardiomyocyte pH homeostasis by controlling Na+-H+ exchanger-1 expression. J Mol Cell Biol 2015; 7:476-85. [PMID: 26260029 DOI: 10.1093/jmcb/mjv054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 06/08/2015] [Indexed: 12/23/2022] Open
Abstract
The mammalian nuclear pore complex is comprised of ∼ 30 different nucleoporins (Nups). It governs the nuclear import of gene expression modulators and the export of mRNAs. In cardiomyocytes, Na(+)-H(+) exchanger-1 (NHE1) is an integral membrane protein that exclusively regulates intracellular pH (pHi) by exchanging one intracellular H(+) for one extracellular Na(+). However, the role of Nups in cardiac NHE1 expression remains unknown. We herein report that Nup35 regulates cardiomyocyte NHE1 expression by controlling the nucleo-cytoplasmic trafficking of nhe1 mRNA. The N-terminal domain of Nup35 determines nhe1 mRNA nuclear export by targeting the 5'-UTR (-412 to -213 nt) of nhe1 mRNA. Nup35 ablation weakens the resistance of cardiomyocytes to an acid challenge by depressing NHE1 expression. Moreover, we identify that Nup35 and NHE1 are simultaneously downregulated in ischemic cardiomyocytes both in vivo and in vitro. Enforced expression of Nup35 effectively counteracts the anoxia-induced intracellular acidification. We conclude that Nup35 selectively regulates cardiomyocyte pHi homeostasis by posttranscriptionally controlling NHE1 expression. This finding reveals a novel regulatory mechanism of cardiomyocyte pHi, and may provide insight into the therapeutic strategy for ischemic cardiac diseases.
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Affiliation(s)
- Liang Xu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China
| | - Lei Pan
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Jun Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Bijun Huang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Jing Feng
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Changming Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Shiyi Wang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Erlinda The
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Yuan Liu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Tianyou Yuan
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China
| | - Lixiao Zhen
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Dandan Liang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China
| | - Yi Liu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China
| | - Li Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Yingyu Cui
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Xiaoyan Jiang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Luying Peng
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Yi-Han Chen
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Institute of Medical Genetics, Tongji University, Shanghai 200092, China Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai 200092, China
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18
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Wirthmueller L, Roth C, Fabro G, Caillaud MC, Rallapalli G, Asai S, Sklenar J, Jones AME, Wiermer M, Jones JDG, Banfield MJ. Probing formation of cargo/importin-α transport complexes in plant cells using a pathogen effector. Plant J 2015; 81:40-52. [PMID: 25284001 PMCID: PMC4350430 DOI: 10.1111/tpj.12691] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 05/17/2023]
Abstract
Importin-αs are essential adapter proteins that recruit cytoplasmic proteins destined for active nuclear import to the nuclear transport machinery. Cargo proteins interact with the importin-α armadillo repeat domain via nuclear localization sequences (NLSs), short amino acids motifs enriched in Lys and Arg residues. Plant genomes typically encode several importin-α paralogs that can have both specific and partially redundant functions. Although some cargos are preferentially imported by a distinct importin-α it remains unknown how this specificity is generated and to what extent cargos compete for binding to nuclear transport receptors. Here we report that the effector protein HaRxL106 from the oomycete pathogen Hyaloperonospora arabidopsidis co-opts the host cell's nuclear import machinery. We use HaRxL106 as a probe to determine redundant and specific functions of importin-α paralogs from Arabidopsis thaliana. A crystal structure of the importin-α3/MOS6 armadillo repeat domain suggests that five of the six Arabidopsis importin-αs expressed in rosette leaves have an almost identical NLS-binding site. Comparison of the importin-α binding affinities of HaRxL106 and other cargos in vitro and in plant cells suggests that relatively small affinity differences in vitro affect the rate of transport complex formation in vivo. Our results suggest that cargo affinity for importin-α, sequence variation at the importin-α NLS-binding sites and tissue-specific expression levels of importin-αs determine formation of cargo/importin-α transport complexes in plant cells.
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Affiliation(s)
- Lennart Wirthmueller
- The Sainsbury LaboratoryNorwich Research Park, Norwich, NR4 7UH, UK
- Department of Biological Chemistry, John Innes CentreNorwich Research Park, Norwich, NR4 7UH, UK
| | - Charlotte Roth
- Department of Plant Cell Biology, Georg-August-UniversityJulia-Lermontowa-Weg 3, 37077, Goettingen, Germany
| | - Georgina Fabro
- The Sainsbury LaboratoryNorwich Research Park, Norwich, NR4 7UH, UK
| | | | | | - Shuta Asai
- The Sainsbury LaboratoryNorwich Research Park, Norwich, NR4 7UH, UK
| | - Jan Sklenar
- The Sainsbury LaboratoryNorwich Research Park, Norwich, NR4 7UH, UK
| | | | - Marcel Wiermer
- Department of Plant Cell Biology, Georg-August-UniversityJulia-Lermontowa-Weg 3, 37077, Goettingen, Germany
| | | | - Mark J Banfield
- Department of Biological Chemistry, John Innes CentreNorwich Research Park, Norwich, NR4 7UH, UK
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19
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Abstract
Cytoplasmic poly(A)-binding proteins (PABPs) regulate mRNA stability and translation. Although predominantly localized in the cytoplasm, PABP proteins also cycle through the nucleus. Recent work has established that their steady-state localization can be altered by cellular stresses such as ultraviolet (UV) radiation, and infection by several viruses, resulting in nuclear accumulation of PABPs. Here, we present further evidence that their interaction with and release from mRNA and translation complexes are important in determining their sub-cellular distribution and propose an integrated model for regulated nucleo-cytoplasmic transport of PABPs.
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20
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Abstract
Here, we review the sn- and sno-RNA transport pathways in S. cerevisiae and humans, aiming at understanding how they evolved and how common factors can have distinct functions depending on the RNA they bind. We give a particular emphasis on Tgs1, the cap hypermethylase that is conserved from yeast to humans and appears to play a central role in both sn- and sno-RNA biogenesis. In yeast, Tgs1 hypermethylates sn- and sno-RNAs in the nucleolus. In humans, Tgs1 occurs in two forms: a long isoform (Tgs1 LF), which locates in the cytoplasm and Cajal bodies, which is predominantly associated with snRNAs and a short isoform (Tgs1 SF), which is nuclear and mainly associates with snoRNAs. We show that Tgs1 LF is exported by CRM1 and that interaction with CRM1 competes for binding with the C-terminal domain of the core protein Nop58, which contains the Nucleolar localization signal of Box C/D snoRNPs (NoLS). Our data suggest a model where CRM1 removes Tgs1 LF from snoRNPs, thereby promoting nucleolar targeting via activation of their NoLS. In this review, we argue that CRM1, while first described as an export receptor, can also control the composition of nucleoplasmic complexes. Thus, it could coordinate the fate of these complexes with the general nucleo-cytoplasmic trafficking.
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Affiliation(s)
- Celine Verheggen
- Institut de Génétique Moléculaire de Montpellier; Université Montpellier I and II; Montpellier, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier; Université Montpellier I and II; Montpellier, France
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21
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Haudek KC, Spronk KJ, Voss PG, Patterson RJ, Wang JL, Arnoys EJ. Dynamics of galectin-3 in the nucleus and cytoplasm. Biochim Biophys Acta 2010; 1800:181-9. [PMID: 19616076 PMCID: PMC2815258 DOI: 10.1016/j.bbagen.2009.07.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 07/06/2009] [Indexed: 11/29/2022]
Abstract
This review summarizes selected studies on galectin-3 (Gal3) as an example of the dynamic behavior of a carbohydrate-binding protein in the cytoplasm and nucleus of cells. Within the 15-member galectin family of proteins, Gal3 (M(r) approximately 30,000) is the sole representative of the chimera subclass in which a proline- and glycine-rich NH(2)-terminal domain is fused onto a COOH-terminal carbohydrate recognition domain responsible for binding galactose-containing glycoconjugates. The protein shuttles between the cytoplasm and nucleus on the basis of targeting signals that are recognized by importin(s) for nuclear localization and exportin-1 (CRM1) for nuclear export. Depending on the cell type, specific experimental conditions in vitro, or tissue location, Gal3 has been reported to be exclusively cytoplasmic, predominantly nuclear, or distributed between the two compartments. The nuclear versus cytoplasmic distribution of the protein must reflect, then, some balance between nuclear import and export, as well as mechanisms of cytoplasmic anchorage or binding to a nuclear component. Indeed, a number of ligands have been reported for Gal3 in the cytoplasm and in the nucleus. Most of the ligands appear to bind Gal3, however, through protein-protein interactions rather than through protein-carbohydrate recognition. In the cytoplasm, for example, Gal3 interacts with the apoptosis repressor Bcl-2 and this interaction may be involved in Gal3's anti-apoptotic activity. In the nucleus, Gal3 is a required pre-mRNA splicing factor; the protein is incorporated into spliceosomes via its association with the U1 small nuclear ribonucleoprotein (snRNP) complex. Although the majority of these interactions occur via the carbohydrate recognition domain of Gal3 and saccharide ligands such as lactose can perturb some of these interactions, the significance of the protein's carbohydrate-binding activity, per se, remains a challenge for future investigations.
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Affiliation(s)
- Kevin C. Haudek
- Department of Biochemistry and Molecular Biology Michigan State University, East Lansing, MI 48824
| | - Kimberly J. Spronk
- Department of Chemistry and Biochemistry Calvin College, Grand Rapids, MI 49546
| | - Patricia G. Voss
- Department of Biochemistry and Molecular Biology Michigan State University, East Lansing, MI 48824
| | - Ronald J. Patterson
- Department of Microbiology and Molecular Genetics Michigan State University, East Lansing, MI 48824
| | - John L. Wang
- Department of Biochemistry and Molecular Biology Michigan State University, East Lansing, MI 48824
| | - Eric J. Arnoys
- Department of Chemistry and Biochemistry Calvin College, Grand Rapids, MI 49546
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22
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Abstract
Analysis of virus-host interactions has revealed a variety of ways in which viruses utilize and/or alter host functions in an effort to facilitate efficient replication. Recent work has suggested that certain RNA viruses that replicate in the cytoplasm disrupt the normal trafficking of cellular RNAs and proteins within the host cell. This review will examine the recent evidence showing that poliovirus and vesicular stomatitis virus (VSV) can inhibit nucleo-cytoplasmic transport within cells. Interestingly, the data indicate that inhibition by both viruses involves targeting components of the nuclear pore complex (NPC). Following this, several possible explanations for why viruses might disrupt nucleo-cytoplasmic transport are discussed. Finally, the possibility that disruption of nucleo-cytoplasmic trafficking may be a more common feature of RNA virus-host interactions than previously thought is examined.
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Affiliation(s)
- Kurt E Gustin
- Department of Microbiology, University of Idaho, Moscow, ID 83844, USA.
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