499 results on '"NUCLEAR pore complex"'
Search Results
2. Role of charge in enhanced nuclear transport and retention of graphene quantum dots.
- Author
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Gorav G, Khedekar V, Varier GK, and Nandakumar P
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- Humans, HeLa Cells, Nuclear Envelope metabolism, Nuclear Pore metabolism, Microscopy, Confocal, Quantum Dots chemistry, Quantum Dots metabolism, Graphite chemistry, Active Transport, Cell Nucleus, Cell Nucleus metabolism
- Abstract
The nuclear pore complexes on the nuclear membrane serve as the exclusive gateway for communication between the nucleus and the cytoplasm, regulating the transport of various molecules, including nucleic acids and proteins. The present work investigates the kinetics of the transport of negatively charged graphene quantum dots through nuclear membranes, focusing on quantifying their transport characteristics. Experiments are carried out in permeabilized HeLa cells using time-lapse confocal fluorescence microscopy. Our findings indicate that negatively charged graphene quantum dots exhibit rapid transport to the nuclei, involving two distinct transport pathways in the translocation process. Complementary experiments on the nuclear import and export of graphene quantum dots validate the bi-directionality of transport, as evidenced by comparable transport rates. The study also shows that the negatively charged graphene quantum dots possess favorable retention properties, underscoring their potential as drug carriers., (© 2024. The Author(s).)
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- 2024
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3. The molecular architecture of the nuclear basket.
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Singh D, Soni N, Hutchings J, Echeverria I, Shaikh F, Duquette M, Suslov S, Li Z, van Eeuwen T, Molloy K, Shi Y, Wang J, Guo Q, Chait BT, Fernandez-Martinez J, Rout MP, Sali A, and Villa E
- Abstract
The nuclear pore complex (NPC) is the sole mediator of nucleocytoplasmic transport. Despite great advances in understanding its conserved core architecture, the peripheral regions can exhibit considerable variation within and between species. One such structure is the cage-like nuclear basket. Despite its crucial roles in mRNA surveillance and chromatin organization, an architectural understanding has remained elusive. Using in-cell cryo-electron tomography and subtomogram analysis, we explored the NPC's structural variations and the nuclear basket across fungi (yeast; S. cerevisiae), mammals (mouse; M. musculus), and protozoa (T. gondii). Using integrative structural modeling, we computed a model of the basket in yeast and mammals that revealed how a hub of nucleoporins (Nups) in the nuclear ring binds to basket-forming Mlp/Tpr proteins: the coiled-coil domains of Mlp/Tpr form the struts of the basket, while their unstructured termini constitute the basket distal densities, which potentially serve as a docking site for mRNA preprocessing before nucleocytoplasmic transport., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2024
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4. Biallelic NDC1 variants that interfere with ALADIN binding are associated with neuropathy and triple A-like syndrome.
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Smits DJ, Dekker J, Douben H, Schot R, Magee H, Bakhtiari S, Koehler K, Huebner A, Schuelke M, Darvish H, Vosoogh S, Tafakhori A, Jameie M, Taghiabadi E, Wilson Y, Shah M, van Slegtenhorst MA, Medici-van den Herik EG, van Ham TJ, Kruer MC, and Mancini GMS
- Abstract
Nuclear pore complexes (NPCs) regulate nucleocytoplasmic transport and are anchored in the nuclear envelope by the transmembrane nucleoporin NDC1. NDC1 is essential for post-mitotic NPC assembly and the recruitment of ALADIN to the nuclear envelope. While no human disorder has been associated to one of the three transmembrane nucleoporins, biallelic variants in AAAS, encoding ALADIN, cause triple A syndrome (Allgrove syndrome). Triple A syndrome, characterized by alacrima, achalasia, and adrenal insufficiency, often includes progressive demyelinating polyneuropathy and other neurological complaints. In this report, diagnostic exome and/or RNA sequencing was performed in seven individuals from four unrelated consanguineous families with AAAS-negative triple A syndrome. Molecular and clinical studies followed to elucidate the pathogenic mechanism. The affected individuals presented with intellectual disability, motor impairment, severe demyelinating with secondary axonal polyneuropathy, alacrima, and achalasia. None of the affected individuals has adrenal insufficiency. All individuals presented with biallelic NDC1 in-frame deletions or missense variants that affect amino acids and protein domains required for ALADIN binding. No other significant variants associated with the phenotypic features were reported. Skin fibroblasts derived from affected individuals show decreased recruitment of ALADIN to the NE and decreased post-mitotic NPC insertion, confirming pathogenicity of the variants. Taken together, our results implicate biallelic NDC1 variants in the pathogenesis of polyneuropathy and a triple A-like disorder without adrenal insufficiency, by interfering with physiological NDC1 functions, including the recruitment of ALADIN to the NPC., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2024
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5. Evolutionary trajectory for nuclear functions of ciliary transport complex proteins.
- Author
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Ewerling A and May-Simera HL
- Abstract
SUMMARYCilia and the nucleus were two defining features of the last eukaryotic common ancestor. In early eukaryotic evolution, these structures evolved through the diversification of a common membrane-coating ancestor, the protocoatomer. While in cilia, the descendants of this protein complex evolved into parts of the intraflagellar transport complexes and BBSome, the nucleus gained its selectivity by recruiting protocoatomer-like proteins to the nuclear envelope to form the selective nuclear pore complexes. Recent studies show a growing number of proteins shared between the proteomes of the respective organelles, and it is currently unknown how ciliary transport proteins could acquire nuclear functions and vice versa . The nuclear functions of ciliary proteins are still observable today and remain relevant for the understanding of the disease mechanisms behind ciliopathies. In this work, we review the evolutionary history of cilia and nucleus and their respective defining proteins and integrate current knowledge into theories for early eukaryotic evolution. We postulate a scenario where both compartments co-evolved and that fits current models of eukaryotic evolution, explaining how ciliary proteins and nucleoporins acquired their dual functions.
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- 2024
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6. Rapid evolution of promoters from germline-specifically expressed genes including transposon silencing factors.
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McQuarrie DWJ, Alizada A, Nicholson BC, and Soller M
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- Animals, Drosophila Proteins genetics, Drosophila genetics, Argonaute Proteins genetics, DNA Transposable Elements genetics, Promoter Regions, Genetic, Evolution, Molecular, Germ Cells metabolism, Gene Silencing, RNA, Small Interfering genetics, RNA, Small Interfering metabolism
- Abstract
Background: The piRNA pathway in animal gonads functions as an 'RNA-based immune system', serving to silence transposable elements and prevent inheritance of novel invaders. In Drosophila, this pathway relies on three gonad-specific Argonaute proteins (Argonaute-3, Aubergine and Piwi) that associate with 23-28 nucleotide piRNAs, directing the silencing of transposon-derived transcripts. Transposons constitute a primary driver of genome evolution, yet the evolution of piRNA pathway factors has not received in-depth exploration. Specifically, channel nuclear pore proteins, which impact piRNA processing, exhibit regions of rapid evolution in their promoters. Consequently, the question arises whether such a mode of evolution is a general feature of transposon silencing pathways., Results: By employing genomic analysis of coding and promoter regions within genes that function in transposon silencing in Drosophila, we demonstrate that the promoters of germ cell-specific piRNA factors are undergoing rapid evolution. Our findings indicate that rapid promoter evolution is a common trait among piRNA factors engaged in germline silencing across insect species, potentially contributing to gene expression divergence in closely related taxa. Furthermore, we observe that the promoters of genes exclusively expressed in germ cells generally exhibit rapid evolution, with some divergence in gene expression., Conclusion: Our results suggest that increased germline promoter evolution, in partnership with other factors, could contribute to transposon silencing and evolution of species through differential expression of genes driven by invading transposons., (© 2024. The Author(s).)
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- 2024
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7. Unlocking the Gateway: The Spatio-Temporal Dynamics of the p53 Family Driven by the Nuclear Pores and Its Implication for the Therapeutic Approach in Cancer.
- Author
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Ikliptikawati DK, Makiyama K, Hazawa M, and Wong RW
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- Humans, Animals, Gene Expression Regulation, Neoplastic, Tumor Suppressor Protein p53 genetics, Tumor Suppressor Protein p53 metabolism, Neoplasms genetics, Neoplasms metabolism, Neoplasms pathology, Nuclear Pore metabolism, Nuclear Pore genetics
- Abstract
The p53 family remains a captivating focus of an extensive number of current studies. Accumulating evidence indicates that p53 abnormalities rank among the most prevalent in cancer. Given the numerous existing studies, which mostly focus on the mutations, expression profiles, and functional perturbations exhibited by members of the p53 family across diverse malignancies, this review will concentrate more on less explored facets regarding p53 activation and stabilization by the nuclear pore complex (NPC) in cancer, drawing on several studies. p53 integrates a broad spectrum of signals and is subject to diverse regulatory mechanisms to enact the necessary cellular response. It is widely acknowledged that each stage of p53 regulation, from synthesis to degradation, significantly influences its functionality in executing specific tasks. Over recent decades, a large body of data has established that mechanisms of regulation, closely linked with protein activation and stabilization, involve intricate interactions with various cellular components. These often transcend canonical regulatory pathways. This new knowledge has expanded from the regulation of genes themselves to epigenomics and proteomics, whereby interaction partners increase in number and complexity compared with earlier paradigms. Specifically, studies have recently shown the involvement of the NPC protein in such complex interactions, underscoring the further complexity of p53 regulation. Furthermore, we also discuss therapeutic strategies based on recent developments in this field in combination with established targeted therapies.
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- 2024
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8. Reconstitution of nuclear envelope subdomain formation on mitotic chromosomes in semi-intact cells.
- Author
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Funakoshi T and Imamoto N
- Subjects
- Humans, Membrane Proteins metabolism, Membrane Proteins genetics, HeLa Cells, Lamin B Receptor, Receptors, Cytoplasmic and Nuclear metabolism, Receptors, Cytoplasmic and Nuclear genetics, Chromosomes, Human metabolism, Nuclear Pore metabolism, Chromosomes metabolism, Nuclear Envelope metabolism, Mitosis, Nuclear Proteins metabolism
- Abstract
In metazoans, the nuclear envelope (NE) disassembles during the prophase and reassembles around segregated chromatids during the telophase. The process of NE formation has been extensively studied using live-cell imaging. At the early step of NE reassembly in human cells, specific pattern-like localization of inner nuclear membrane (INM) proteins, connected to the nuclear pore complex (NPC), was observed in the so-called "core" region and "noncore" region on telophase chromosomes, which corresponded to the "pore-free" region and the "pore-rich" region, respectively, in the early G1 interphase nucleus. We refer to these phenomena as NE subdomain formation. To biochemically investigate this process, we aimed to develop an in vitro NE reconstitution system using digitonin-permeabilized semi-intact mitotic human cells coexpressing two INM proteins, emerin and lamin B receptor, which were labeled with fluorescent proteins. The targeting and accumulation of INM proteins to chromosomes before and after anaphase onset in semi-intact cells were observed using time-lapse imaging. Our in vitro NE reconstitution system recapitulated the formation of the NE subdomain, as in living cells, although chromosome segregation and cytokinesis were not observed. This in vitro NE reconstitution required the addition of a mitotic cytosolic fraction supplemented with a cyclin-dependent kinase inhibitor and energy sources. The cytoplasmic soluble factor(s) dependency of INM protein targeting differed among the segregation states of chromosomes. Furthermore, the NE reconstituted on segregated chromosomes exhibited active nucleocytoplasmic transport competency. These results indicate that the chromosome status changes after anaphase onset for recruiting NPC components.
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- 2024
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9. Nucleoporin Nup98 is an essential factor for ipo4 dependent protein import.
- Author
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Guo Y, Tao T, Wu T, Hou J, and Lin W
- Subjects
- Humans, Cell Nucleus metabolism, HeLa Cells, Protein Binding, Active Transport, Cell Nucleus, beta Karyopherins metabolism, beta Karyopherins genetics, Nuclear Pore Complex Proteins metabolism, Nuclear Pore Complex Proteins genetics
- Abstract
Nucleocytoplasmic transport of macromolecules is essential in eukaryotic cells. In this process, the karyopherins play a central role when they transport cargoes across the nuclear pore complex. Importin 4 belongs to the karyopherin β family. Many studies have focused on finding substrates for importin 4, but no direct mechanism studies of its precise transport function have been reported. Therefore, this paper mainly aimed to study the mechanism of nucleoporins in mediating nuclear import and export of importin 4. To address this question, we constructed shRNAs targeting Nup358, Nup153, Nup98, and Nup50. We found that depletion of Nup98 resulted in a shift in the subcellular localization of importin 4 from the cytoplasm to the nucleus. Mutational analysis demonstrated that Nup98 physically and functionally interacts with importin 4 through its N-terminal phenylalanine-glycine (FG) repeat region. Mutation of nine of these FG motifs to SG motifs significantly attenuated the binding of Nup98 to importin 4, and we further confirmed the essential role of the six FG motifs in amino acids 121-360 of Nup98 in binding with importin 4. In vitro transport assay also confirmed that VDR, the substrate of importin 4, could not be transported into the nucleus after Nup98 knockdown. Overall, our results showed that Nup98 is required for efficient importin 4-mediated transport. This is the first study to reveal the mechanism of importin 4 in transporting substrates into the nucleus., (© 2024 Wiley Periodicals LLC.)
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- 2024
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10. Cytoplasmic nucleoporin assemblage: the cellular artwork in physiology and disease.
- Author
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Lin J and Sumara I
- Subjects
- Humans, Animals, Nuclear Pore metabolism, Active Transport, Cell Nucleus, Nuclear Pore Complex Proteins metabolism, Cytoplasm metabolism
- Abstract
Nucleoporins, essential proteins building the nuclear pore, are pivotal for ensuring nucleocytoplasmic transport. While traditionally confined to the nuclear envelope, emerging evidence indicates their presence in various cytoplasmic structures, suggesting potential non-transport-related roles. This review consolidates findings on cytoplasmic nucleoporin assemblies across different states, including normal physiological conditions, stress, and pathology, exploring their structural organization, formation dynamics, and functional implications. We summarize the current knowledge and the latest concepts on the regulation of nucleoporin homeostasis, aiming to enhance our understanding of their unexpected roles in physiological and pathological processes.
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- 2024
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11. Nuclear pore dysfunction and disease: a complex opportunity.
- Author
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Fare CM and Rothstein JD
- Subjects
- Humans, Cell Nucleus metabolism, Active Transport, Cell Nucleus physiology, Nuclear Pore Complex Proteins metabolism, Nuclear Pore metabolism, Neurodegenerative Diseases metabolism
- Abstract
The separation of genetic material from bulk cytoplasm has enabled the evolution of increasingly complex organisms, allowing for the development of sophisticated forms of life. However, this complexity has created new categories of dysfunction, including those related to the movement of material between cellular compartments. In eukaryotic cells, nucleocytoplasmic trafficking is a fundamental biological process, and cumulative disruptions to nuclear integrity and nucleocytoplasmic transport are detrimental to cell survival. This is particularly true in post-mitotic neurons, where nuclear pore injury and errors to nucleocytoplasmic trafficking are strongly associated with neurodegenerative disease. In this review, we summarize the current understanding of nuclear pore biology in physiological and pathological contexts and discuss potential therapeutic approaches for addressing nuclear pore injury and dysfunctional nucleocytoplasmic transport.
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- 2024
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12. Mechanobiology of the nucleus during the G2-M transition.
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Lima JT and Ferreira JG
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- Mitosis, Cytoskeleton metabolism, Biophysics, Mechanotransduction, Cellular, Cell Nucleus metabolism
- Abstract
Cellular behavior is continuously influenced by mechanical forces. These forces span the cytoskeleton and reach the nucleus, where they trigger mechanotransduction pathways that regulate downstream biochemical events. Therefore, the nucleus has emerged as a regulator of cellular response to mechanical stimuli. Cell cycle progression is regulated by cyclin-CDK complexes. Recent studies demonstrated these biochemical pathways are influenced by mechanical signals, highlighting the interdependence of cellular mechanics and cell cycle regulation. In particular, the transition from G2 to mitosis (G2-M) shows significant changes in nuclear structure and organization, ranging from nuclear pore complex (NPC) and nuclear lamina disassembly to chromosome condensation. The remodeling of these mechanically active nuclear components indicates that mitotic entry is particularly sensitive to forces. Here, we address how mechanical forces crosstalk with the nucleus to determine the timing and efficiency of the G2-M transition. Finally, we discuss how the deregulation of nuclear mechanics has consequences for mitosis.
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- 2024
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13. A lineage-specific protein network at the trypanosome nuclear envelope.
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Butterfield ER, Obado SO, Scutts SR, Zhang W, Chait BT, Rout MP, and Field MC
- Subjects
- Humans, Nuclear Pore metabolism, Saccharomyces cerevisiae metabolism, Nuclear Pore Complex Proteins metabolism, Nuclear Envelope metabolism, Trypanosoma metabolism
- Abstract
The nuclear envelope (NE) separates translation and transcription and is the location of multiple functions, including chromatin organization and nucleocytoplasmic transport. The molecular basis for many of these functions have diverged between eukaryotic lineages. Trypanosoma brucei , a member of the early branching eukaryotic lineage Discoba, highlights many of these, including a distinct lamina and kinetochore composition. Here, we describe a cohort of proteins interacting with both the lamina and NPC, which we term l amina- a ssociated p roteins (LAPs). LAPs represent a diverse group of proteins, including two candidate NPC-anchoring pore membrane proteins (POMs) with architecture conserved with S. cerevisiae and H. sapiens , and additional peripheral components of the NPC. While many of the LAPs are Kinetoplastid specific, we also identified broadly conserved proteins, indicating an amalgam of divergence and conservation within the trypanosome NE proteome, highlighting the diversity of nuclear biology across the eukaryotes, increasing our understanding of eukaryotic and NPC evolution.
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- 2024
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14. Sculpting nuclear envelope identity from the endoplasmic reticulum during the cell cycle.
- Author
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Deolal P, Scholz J, Ren K, Bragulat-Teixidor H, and Otsuka S
- Subjects
- Endoplasmic Reticulum metabolism, Mitosis, Active Transport, Cell Nucleus, Nuclear Envelope metabolism, Nuclear Pore metabolism
- Abstract
The nuclear envelope (NE) regulates nuclear functions, including transcription, nucleocytoplasmic transport, and protein quality control. While the outer membrane of the NE is directly continuous with the endoplasmic reticulum (ER), the NE has an overall distinct protein composition from the ER, which is crucial for its functions. During open mitosis in higher eukaryotes, the NE disassembles during mitotic entry and then reforms as a functional territory at the end of mitosis to reestablish nucleocytoplasmic compartmentalization. In this review, we examine the known mechanisms by which the functional NE reconstitutes from the mitotic ER in the continuous ER-NE endomembrane system during open mitosis. Furthermore, based on recent findings indicating that the NE possesses unique lipid metabolism and quality control mechanisms distinct from those of the ER, we explore the maintenance of NE identity and homeostasis during interphase. We also highlight the potential significance of membrane junctions between the ER and NE.
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- 2024
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15. Nuclear and degradative functions of the ESCRT-III pathway: implications for neurodegenerative disease.
- Author
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Keeley O and Coyne AN
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- Humans, Animals, Cell Nucleus metabolism, Frontotemporal Dementia metabolism, Frontotemporal Dementia pathology, Frontotemporal Dementia genetics, Endosomes metabolism, Endosomal Sorting Complexes Required for Transport metabolism, Neurodegenerative Diseases metabolism, Neurodegenerative Diseases pathology, Neurodegenerative Diseases genetics
- Abstract
The ESCRT machinery plays a pivotal role in membrane-remodeling events across multiple cellular processes including nuclear envelope repair and reformation, nuclear pore complex surveillance, endolysosomal trafficking, and neuronal pruning. Alterations in ESCRT-III functionality have been associated with neurodegenerative diseases including Frontotemporal Dementia (FTD), Amyotrophic Lateral Sclerosis (ALS), and Alzheimer's Disease (AD). In addition, mutations in specific ESCRT-III proteins have been identified in FTD/ALS. Thus, understanding how disruptions in the fundamental functions of this pathway and its individual protein components in the human central nervous system (CNS) may offer valuable insights into mechanisms underlying neurodegenerative disease pathogenesis and identification of potential therapeutic targets. In this review, we discuss ESCRT components, dynamics, and functions, with a focus on the ESCRT-III pathway. In addition, we explore the implications of altered ESCRT-III function for neurodegeneration with a primary emphasis on nuclear surveillance and endolysosomal trafficking within the CNS.
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- 2024
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16. Not just binary: embracing the complexity of nuclear division dynamics.
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Walsh ME, King GA, and Ünal E
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- Humans, Animals, Cell Nucleus metabolism, Nuclear Envelope metabolism, Chromosomes metabolism, Active Transport, Cell Nucleus, Cell Nucleus Division
- Abstract
Cell division presents a challenge for eukaryotic cells: how can chromosomes effectively segregate within the confines of a membranous nuclear compartment? Different organisms have evolved diverse solutions by modulating the degree of nuclear compartmentalization, ranging from complete nuclear envelope breakdown to complete maintenance of nuclear compartmentalization via nuclear envelope expansion. Many intermediate forms exist between these extremes, suggesting that nuclear dynamics during cell division are surprisingly plastic. In this review, we highlight the evolutionary diversity of nuclear divisions, focusing on two defining characteristics: (1) chromosome compartmentalization and (2) nucleocytoplasmic transport. Further, we highlight recent evidence that nuclear behavior during division can vary within different cellular contexts in the same organism. The variation observed within and between organisms underscores the dynamic evolution of nuclear divisions tailored to specific contexts and cellular requirements. In-depth investigation of diverse nuclear divisions will enhance our understanding of the nucleus, both in physiological and pathological states.
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- 2024
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17. Altered nucleocytoplasmic export of adenosine-rich circRNAs by PABPC1 contributes to neuronal function.
- Author
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Cao SM, Wu H, Yuan GH, Pan YH, Zhang J, Liu YX, Li S, Xu YF, Wei MY, Yang L, and Chen LL
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- Humans, Animals, Cell Line, Cell Differentiation, Cytoplasm metabolism, Prosencephalon metabolism, RNA, Circular metabolism, RNA, Circular genetics, Neurons metabolism, Active Transport, Cell Nucleus, Adenosine metabolism, Cell Nucleus metabolism, Neurogenesis, Poly(A)-Binding Protein I metabolism, Poly(A)-Binding Protein I genetics, RNA metabolism, RNA genetics
- Abstract
Circular RNAs (circRNAs) are upregulated during neurogenesis. Where and how circRNAs are localized and what roles they play during this process have remained elusive. Comparing the nuclear and cytoplasmic circRNAs between H9 cells and H9-derived forebrain (FB) neurons, we identify that a subset of adenosine (A)-rich circRNAs are restricted in H9 nuclei but exported to cytosols upon differentiation. Such a subcellular relocation of circRNAs is modulated by the poly(A)-binding protein PABPC1. In the H9 nucleus, newly produced (A)-rich circRNAs are bound by PABPC1 and trapped by the nuclear basket protein TPR to prevent their export. Modulating (A)-rich motifs in circRNAs alters their subcellular localization, and introducing (A)-rich circRNAs in H9 cytosols results in mRNA translation suppression. Moreover, decreased nuclear PABPC1 upon neuronal differentiation enables the export of (A)-rich circRNAs, including circRTN4(2,3), which is required for neurite outgrowth. These findings uncover subcellular localization features of circRNAs, linking their processing and function during neurogenesis., Competing Interests: Declaration of interests L.-L.C. is a member of the Molecular Cell advisory board and a scientific co-founder of RiboX Therapeutics., (Copyright © 2024 Elsevier Inc. All rights reserved.)
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- 2024
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18. Unravelling the interaction between Influenza virus and the nuclear pore complex: insights into viral replication and host immune response.
- Author
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Khanna M, Sharma K, Saxena SK, Sharma JG, Rajput R, and Kumar B
- Abstract
Influenza viruses are known to cause severe respiratory infections in humans, often associated with significant morbidity and mortality rates. Virus replication relies on various host factors and pathways, which also determine the virus's infectious potential. Nonetheless, achieving a comprehensive understanding of how the virus interacts with host cellular components is essential for developing effective therapeutic strategies. One of the key components among host factors, the nuclear pore complex (NPC), profoundly affects both the Influenza virus life cycle and the host's antiviral defenses. Serving as the sole gateway connecting the cytoplasm and nucleoplasm, the NPC plays a vital role as a mediator in nucleocytoplasmic trafficking. Upon infection, the virus hijacks and alters the nuclear pore complex and the nuclear receptors. This enables the virus to infiltrate the nucleus and promotes the movement of viral components between the nucleus and cytoplasm. While the nucleus and cytoplasm play pivotal roles in cellular functions, the nuclear pore complex serves as a crucial component in the host's innate immune system, acting as a defense mechanism against virus infection. This review provides a comprehensive overview of the intricate relationship between the Influenza virus and the nuclear pore complex. Furthermore, we emphasize their mutual influence on viral replication and the host's immune responses., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s), under exclusive licence to Indian Virological Society 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
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- 2024
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19. Improved detection of DNA replication fork-associated proteins.
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Rivard RS, Chang YC, Ragland RL, Thu YM, Kassab M, Mandal RS, Van Riper SK, Kulej K, Higgins L, Markowski TM, Shang D, Hedberg J, Erber L, Garcia B, Chen Y, Bielinsky AK, and Brown EJ
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- Humans, DNA Repair, DNA metabolism, DNA Replication, Ubiquitination
- Abstract
Innovative methods to retrieve proteins associated with actively replicating DNA have provided a glimpse into the molecular dynamics of replication fork stalling. We report that a combination of density-based replisome enrichment by isolating proteins on nascent DNA (iPOND2) and label-free quantitative mass spectrometry (iPOND2-DRIPPER) substantially increases both replication factor yields and the dynamic range of protein quantification. Replication protein abundance in retrieved nascent DNA is elevated up to 300-fold over post-replicative controls, and recruitment of replication stress factors upon fork stalling is observed at similar levels. The increased sensitivity of iPOND2-DRIPPER permits direct measurement of ubiquitination events without intervening retrieval of diglycine tryptic fragments of ubiquitin. Using this approach, we find that stalled replisomes stimulate the recruitment of a diverse cohort of DNA repair factors, including those associated with poly-K63-ubiquitination. Finally, we uncover the temporally controlled association of stalled replisomes with nuclear pore complex components and nuclear cytoskeleton networks., Competing Interests: Declaration of interests E.J.B. serves on the scientific advisory board of Aprea Therapeutics, and he consults for and holds equity in this company., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2024
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20. Super-enhancer trapping by the nuclear pore via intrinsically disordered regions of proteins in squamous cell carcinoma cells.
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Hazawa M, Ikliptikawati DK, Iwashima Y, Lin DC, Jiang Y, Qiu Y, Makiyama K, Matsumoto K, Kobayashi A, Nishide G, Keesiang L, Yoshino H, Minamoto T, Suzuki T, Kobayashi I, Meguro-Horike M, Jiang YY, Nishiuchi T, Konno H, Koeffler HP, Hosomichi K, Tajima A, Horike SI, and Wong RW
- Subjects
- Humans, Transcription Factors metabolism, Nuclear Proteins metabolism, Nuclear Pore Complex Proteins genetics, Nuclear Pore Complex Proteins metabolism, Bromodomain Containing Proteins, Cell Cycle Proteins metabolism, Nuclear Pore metabolism, Nuclear Pore pathology, Carcinoma, Squamous Cell genetics, Carcinoma, Squamous Cell metabolism, Carcinoma, Squamous Cell pathology
- Abstract
Master transcription factors such as TP63 establish super-enhancers (SEs) to drive core transcriptional networks in cancer cells, yet the spatiotemporal regulation of SEs within the nucleus remains unknown. The nuclear pore complex (NPC) may tether SEs to the nuclear pore where RNA export rates are maximal. Here, we report that NUP153, a component of the NPC, anchors SEs to the NPC and enhances TP63 expression by maximizing mRNA export. This anchoring is mediated through protein-protein interaction between the intrinsically disordered regions (IDRs) of NUP153 and the coactivator BRD4. Silencing of NUP153 excludes SEs from the nuclear periphery, decreases TP63 expression, impairs cellular growth, and induces epidermal differentiation of squamous cell carcinoma. Overall, this work reveals the critical roles of NUP153 IDRs in the regulation of SE localization, thus providing insights into a new layer of gene regulation at the epigenomic and spatial level., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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21. Role of the San1 ubiquitin ligase in the heat stress-induced degradation of nonnative Nup1 in the nuclear pore complex.
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Ikeda T, Yamazaki K, Okumura F, Kamura T, and Nakatsukasa K
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- Nuclear Pore genetics, Nuclear Pore chemistry, Nuclear Pore metabolism, Nuclear Pore Complex Proteins genetics, Nuclear Pore Complex Proteins metabolism, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, Ubiquitin analysis, Ubiquitin genetics, Ubiquitin metabolism, Ubiquitin-Protein Ligases genetics, Ubiquitin-Protein Ligases metabolism, Proteasome Endopeptidase Complex metabolism, Saccharomyces cerevisiae Proteins genetics, Saccharomyces cerevisiae Proteins metabolism
- Abstract
The nuclear pore complex (NPC) mediates the selective exchange of macromolecules between the nucleus and the cytoplasm. Neurodegenerative diseases such as amyotrophic lateral sclerosis are characterized by mislocalization of nucleoporins (Nups), transport receptors, and Ras-related nuclear proteins into nucleoplasmic or cytosolic aggregates, underscoring the importance of precise assembly of the NPC. The assembly state of large protein complexes is strictly monitored by the protein quality control system. The ubiquitin-proteasome system may eliminate aberrant, misfolded, and/or orphan components; however, the involvement of the ubiquitin-proteasome system in the degradation of nonnative Nups in the NPC remains unclear. Here, we show that in Saccharomyces cerevisiae, although Nup1 (the FG-Nup component of the central core of the NPC) was stable, C-terminally green fluorescent protein-tagged Nup1, which had been incorporated into the NPC, was degraded by the proteasome especially under heat stress conditions. The degradation was dependent on the San1 ubiquitin ligase and Cdc48/p97, as well as its cofactor Doa1. We also demonstrate that San1 weakly but certainly contributes to the degradation of nontagged endogenous Nup1 in cells defective in NPC biogenesis by the deletion of NUP120. In addition, the overexpression of SAN1 exacerbated the growth defect phenotype of nup120Δ cells, which may be caused by excess degradation of defective Nups due to the deletion of NUP120. These biochemical and genetic data suggest that San1 is involved in the degradation of nonnative Nups generated by genetic mutation or when NPC biogenesis is impaired., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2024
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22. Nucleoporin93 limits Yap activity to prevent endothelial cell senescence.
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Nguyen TD, Rao MK, Dhyani SP, Banks JM, Winek MA, Michalkiewicz J, and Lee MY
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- Humans, Mice, Animals, Aging physiology, Cells, Cultured, Inflammation metabolism, Endothelial Cells metabolism, Cellular Senescence
- Abstract
As the innermost lining of the vasculature, endothelial cells (ECs) are constantly subjected to systemic inflammation and particularly vulnerable to aging. Endothelial health is hence vital to prevent age-related vascular disease. Healthy ECs rely on the proper localization of transcription factors via nuclear pore complexes (NPCs) to govern cellular behavior. Emerging studies report NPC degradation with natural aging, suggesting impaired nucleocytoplasmic transport in age-associated EC dysfunction. We herein identify nucleoporin93 (Nup93), a crucial structural NPC protein, as an indispensable player in vascular protection. Endothelial Nup93 protein levels are significantly reduced in the vasculature of aged mice, paralleling observations of Nup93 loss when using in vitro models of EC senescence. The loss of Nup93 in human ECs induces cell senescence and promotes the expression of inflammatory adhesion molecules, where restoring Nup93 protein in senescent ECs reverses features of endothelial aging. Mechanistically, we find that both senescence and loss of Nup93 impair endothelial NPC transport, leading to nuclear accumulation of Yap and downstream inflammation. Pharmacological studies indicate Yap hyperactivation as the primary consequence of senescence and Nup93 loss in ECs. Collectively, our findings indicate that the maintenance of endothelial Nup93 is a key determinant of EC health, where aging targets endothelial Nup93 levels to impair NPC function as a novel mechanism of EC senescence and vascular aging., (© 2024 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)
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- 2024
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23. Characteristic and Import Mechanism of Protein Nuclear Translocation.
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Sun ZY and Fan ZP
- Subjects
- Active Transport, Cell Nucleus, Protein Transport, Cytoplasm, Cell Nucleus, Eukaryotic Cells
- Abstract
Coordination and information exchange among the various organelles ensure the precise and orderly functioning of eukaryotic cells. Interaction between the cytoplasm and nucleoplasm is crucial for many physiological processes. Macromolecular protein transport into the nucleus requires assistance from the nuclear transport system. These proteins typically contain a nuclear localisation sequence that guides them to enter the nucleus. Understanding the mechanism of nuclear import of macromolecular proteins is important for comprehending cellular processes. Investigation of disease-related alterations can facilitate the development of novel therapeutic strategies and provide additional evidence for clinical trials. This review provides an overview of the proteins involved in nuclear transport and the mechanisms underlying macromolecular protein transport.
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- 2024
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24. The Molecular Architecture of the Nuclear Basket.
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Singh D, Soni N, Hutchings J, Echeverria I, Shaikh F, Duquette M, Suslov S, Li Z, van Eeuwen T, Molloy K, Shi Y, Wang J, Guo Q, Chait BT, Fernandez-Martinez J, Rout MP, Sali A, and Villa E
- Abstract
The nuclear pore complex (NPC) is the sole mediator of nucleocytoplasmic transport. Despite great advances in understanding its conserved core architecture, the peripheral regions can exhibit considerable variation within and between species. One such structure is the cage-like nuclear basket. Despite its crucial roles in mRNA surveillance and chromatin organization, an architectural understanding has remained elusive. Using in-cell cryo-electron tomography and subtomogram analysis, we explored the NPC's structural variations and the nuclear basket across fungi (yeast; S. cerevisiae ), mammals (mouse; M. musculus ), and protozoa ( T. gondii ). Using integrative structural modeling, we computed a model of the basket in yeast and mammals that revealed how a hub of Nups in the nuclear ring binds to basket-forming Mlp/Tpr proteins: the coiled-coil domains of Mlp/Tpr form the struts of the basket, while their unstructured termini constitute the basket distal densities, which potentially serve as a docking site for mRNA preprocessing before nucleocytoplasmic transport.
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- 2024
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25. Improving STED microscopy with SUPPOSe: enhancing resolution from a single-image.
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Toscani M and Lacapmesure AM
- Abstract
Here we apply the SUPPOSe algorithm on images acquired using Stimulated Emission Depletion (STED) microscopy with the aim of improving the resolution limit achieved. We processed images of the nuclear pore complex (NPC) from cell lines in which the Nup96 nucleoporin was endogenously labeled. This reference protein forms a ring whose diameter is ∼107 nm with 8 corners ∼42 nm apart from each other. The stereotypic arrangement of proteins in the NPC has been used as reference structures to characterize the performance of a variety of microscopy techniques. STED microscopy images resolve the ring arrangement but not the eightfold symmetry of the NPC. After applying the SUPPOSe algorithm to the STED images, we were able to solve the octagonal structure of the NPC. After processing 562 single NPC, the average radius of the NPC was found to be R = 54.2 ± 2.9 nm, being consistent with the theoretical distances of this structure. To verify that the solutions obtained are compatible with a NPC-type geometry, we rotate the solutions to optimally fit an eightfold-symmetric pattern and we count the number of corners that contain at least one localization. Fitting a probabilistic model to the histogram of the number of bright corners gives an effective labeling efficiency of 31%, which is in agreement with the values reported in for other cell lines and ligands used in Single Molecule Localization microscopy, showing that SUPPOSe can reliably retrieve sub-resolution, nanoscale objects from single acquisitions even in noisy conditions., (© 2024 IOP Publishing Ltd.)
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- 2024
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26. Single nucleotide variants in nuclear pore complex disassembly pathway associated with poor survival in osteosarcoma.
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Jacobs JE, Davis L, and McWeeney S
- Abstract
Introduction: The bone tumor, osteosarcoma, remains challenging to treat in children and young adults, especially when patients present with metastatic disease. Developing new therapies based on genomic data from sequencing projects has proven difficult given the lack of recurrent genetic lesions across tumors. MYC overexpression has been associated with poor outcomes in osteosarcoma. However, other genomic markers of disease severity are lacking., Materials and Methods: We utilized whole genome sequencing of 106 tumors and matched normal controls in order to define genomic characteristics that correlate with overall survival. Single nucleotide variants were overlaid onto annotated molecular pathways in order to define aberrant pathway signatures specific to aggressive osteosarcoma. Additionally, we calculated differential gene expression in a subsample of 71 tumors. Differentially expressed genes were then queried for known MYC-responsive genes., Results: Molecular pathways specific to nuclear pore complex disassembly (NPCD) show significant correlation with poor overall survival in osteosarcoma when mutations were present. Genes involved in immune response and immune regulation are enriched in the differential expression analysis of samples with and without NPCD pathway aberrations. Furthermore, neither MYC nor MYC-responsive genes show differential expression between NPCD-aberrant and non-aberrant groups. The NPCD pathway mutations are dominated by regulatory region variants rather than protein-altering mutations, suggesting that dysregulation of genetic regulatory networks may be the underlying mechanism for their relation to osteosarcoma phenotype., Discussion: Overall survival is significantly worse in patients whose tumors show aberrations in the NPCD pathway. Moreover, this difference in survival is not driven by MYC-overexpression, suggesting a novel mechanism for some aggressive osteosarcomas. These findings add light to the evolving understanding of the drivers of osteosarcoma and may aid in the search for new treatments based on patient-specific genetic data., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Jacobs, Davis and McWeeney.)
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- 2024
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27. C9orf72 polyPR directly binds to various nuclear transport components.
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Jafarinia H, van der Giessen E, and Onck PR
- Subjects
- Active Transport, Cell Nucleus, C9orf72 Protein genetics, Arginine, Nuclear Localization Signals, Amino Acids
- Abstract
The disruption of nucleocytoplasmic transport (NCT) is an important mechanism in neurodegenerative diseases. In the case of C9orf72-ALS, trafficking of macromolecules through the nuclear pore complex (NPC) might get frustrated by the binding of C9orf72-translated arginine-containing dipeptide repeat proteins (R-DPRs) to the Kapβ family of nuclear transport receptors. Besides Kapβs, several other types of transport components have been linked to NCT impairments in R-DPR-expressed cells, but the molecular origin of these observations has not been clarified. Here, we adopt a coarse-grained molecular dynamics model at amino acid resolution to study the direct interaction between polyPR, the most toxic DPR, and various nuclear transport components to elucidate the binding mechanisms and provide a complete picture of potential polyPR-mediated NCT defects. We found polyPR to directly bind to several isoforms of the Impα family, CAS (the specific exporter of Impα) and RanGAP. We observe no binding between polyPR and Ran. Longer polyPRs at lower salt concentrations also make contact with RanGEF and NTF2. Analyzing the polyPR contact sites on the transport components reveals that polyPR potentially interferes with RanGTP/RanGDP binding, with nuclear localization signal (NLS)-containing cargoes (cargo-NLS) binding to Impα, with cargo-NLS release from Impα, and with Impα export from the nucleus. The abundance of polyPR-binding sites on multiple transport components combined with the inherent polyPR length dependence makes direct polyPR interference of NCT a potential mechanistic pathway of C9orf72 toxicity., Competing Interests: HJ, Ev, PO No competing interests declared, (© 2023, Jafarinia et al.)
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- 2024
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28. Nucleoporin Seh1 controls murine neocortical development via transcriptional repression of p21 in neural stem cells.
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Dai W, Liu Z, Yan M, Nian X, Hong F, Zhou Z, Wang C, Fu X, Li X, Jiang M, Zhu Y, Huang Q, Lu X, Hou L, Yan N, Wang Q, Hu J, Mo W, Zhang X, and Zhang L
- Subjects
- Animals, Mice, Cell Differentiation, Gene Expression, Nuclear Pore Complex Proteins genetics, Nuclear Pore Complex Proteins metabolism, Neocortex metabolism, Neural Stem Cells
- Abstract
Mutations or dysregulation of nucleoporins (Nups) are strongly associated with neural developmental diseases, yet the underlying mechanisms remain poorly understood. Here, we show that depletion of Nup Seh1 in radial glial progenitors results in defective neural progenitor proliferation and differentiation that ultimately manifests in impaired neurogenesis and microcephaly. This loss of stem cell proliferation is not associated with defects in the nucleocytoplasmic transport. Rather, transcriptome analysis showed that ablation of Seh1 in neural stem cells derepresses the expression of p21, and knockdown of p21 partially restored self-renewal capacity. Mechanistically, Seh1 cooperates with the NuRD transcription repressor complex at the nuclear periphery to regulate p21 expression. Together, these findings identified that Nups regulate brain development by exerting a chromatin-associated role and affecting neural stem cell proliferation., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)
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- 2024
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29. UCHL1 is a potential molecular indicator and therapeutic target for neuroendocrine carcinomas.
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Liu S, Chai T, Garcia-Marques F, Yin Q, Hsu EC, Shen M, Shaw Toland AM, Bermudez A, Hartono AB, Massey CF, Lee CS, Zheng L, Baron M, Denning CJ, Aslan M, Nguyen HM, Nolley R, Zoubeidi A, Das M, Kunder CA, Howitt BE, Soh HT, Weissman IL, Liss MA, Chin AI, Brooks JD, Corey E, Pitteri SJ, Huang J, and Stoyanova T
- Subjects
- Male, Humans, Ubiquitin Thiolesterase genetics, Ubiquitin Thiolesterase metabolism, Membrane Glycoproteins, Carcinoma, Neuroendocrine drug therapy, Carcinoma, Neuroendocrine genetics, Small Cell Lung Carcinoma, Lung Neoplasms diagnosis, Lung Neoplasms drug therapy
- Abstract
Neuroendocrine carcinomas, such as neuroendocrine prostate cancer and small-cell lung cancer, commonly have a poor prognosis and limited therapeutic options. We report that ubiquitin carboxy-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme, is elevated in tissues and plasma from patients with neuroendocrine carcinomas. Loss of UCHL1 decreases tumor growth and inhibits metastasis of these malignancies. UCHL1 maintains neuroendocrine differentiation and promotes cancer progression by regulating nucleoporin, POM121, and p53. UCHL1 binds, deubiquitinates, and stabilizes POM121 to regulate POM121-associated nuclear transport of E2F1 and c-MYC. Treatment with the UCHL1 inhibitor LDN-57444 slows tumor growth and metastasis across neuroendocrine carcinomas. The combination of UCHL1 inhibitors with cisplatin, the standard of care used for neuroendocrine carcinomas, significantly delays tumor growth in pre-clinical settings. Our study reveals mechanisms of UCHL1 function in regulating the progression of neuroendocrine carcinomas and identifies UCHL1 as a therapeutic target and potential molecular indicator for diagnosing and monitoring treatment responses in these malignancies., Competing Interests: Declaration of interests E.C. is a consultant for Dotquant and received research funding under institutional SRAs from AbbVie, Astra Zeneca, Janssen Research, Gilead, Zenith Epigenetics, Forma Therapeutics, Bayer, Kronos, Foghorn, and MacroGenics. M.D. is a consultant for Regeneron, Beigene, Astra Zeneca, Sanofi/Genzyme, Eurofins, Janssen, and Genentech (uncompensated) and performs research at Merck, Genentech, CellSight, Novartis, AbbVie, United Therapeutics, Varian, Verily, and Celgene. J.H. is a consultant for or owns shares in Kingmed, MoreHealth, OptraScan, Genetron, Omnitura, Vetonco, York Biotechnology, Genecode, VIVA Biotech, and Sisu Pharma and received grants from Zenith Epigenetics, BioXcel Therapeutics, Inc., and Fortis Therapeutics. T.S. is a consultant for Dren Bio., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2024
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30. Diameter dependence of transport through nuclear pore complex mimics studied using optical nanopores.
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Klughammer N, Barth A, Dekker M, Fragasso A, Onck PR, and Dekker C
- Subjects
- Humans, Nuclear Envelope, Biomimetics, Diffusion, Translocation, Genetic, Nuclear Pore, Nanopores
- Abstract
The nuclear pore complex (NPC) regulates the selective transport of large biomolecules through the nuclear envelope. As a model system for nuclear transport, we construct NPC mimics by functionalizing the pore walls of freestanding palladium zero-mode waveguides with the FG-nucleoporin Nsp1. This approach enables the measurement of single-molecule translocations through individual pores using optical detection. We probe the selectivity of Nsp1-coated pores by quantitatively comparing the translocation rates of the nuclear transport receptor Kap95 to the inert probe BSA over a wide range of pore sizes from 35 nm to 160 nm. Pores below 55 ± 5 nm show significant selectivity that gradually decreases for larger pores. This finding is corroborated by coarse-grained molecular dynamics simulations of the Nsp1 mesh within the pore, which suggest that leakage of BSA occurs by diffusion through transient openings within the dynamic mesh. Furthermore, we experimentally observe a modulation of the BSA permeation when varying the concentration of Kap95. The results demonstrate the potential of single-molecule fluorescence measurements on biomimetic NPCs to elucidate the principles of nuclear transport., Competing Interests: NK, AB, MD, AF, PO, CD No competing interests declared, (© 2023, Klughammer, Barth et al.)
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- 2024
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31. Disrupted nuclear import of cell cycle proteins in Huntington's/PolyQ disease causes neurodevelopment defects in cellular and Drosophila model.
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Dubey SK, Lloyd TE, and Tapadia MG
- Abstract
Huntington's disease is caused by an expansion of CAG repeats in exon 1 of the huntingtin gene encoding an extended PolyQ tract within the Huntingtin protein (mHtt). This expansion results in selective degeneration of striatal medium spiny projection neurons in the basal ganglia. The mutation causes abnormalities during neurodevelopment in human and mouse models. Here, we report that mHtt/PolyQ aggregates inhibit the cell cycle in the Drosophila brain during development. PolyQ aggregates disrupt the nuclear pore complexes of the cells preventing the translocation of cell cycle proteins such as Cyclin E, E2F and PCNA from cytoplasm to the nucleus, thus affecting cell cycle progression. PolyQ aggregates also disrupt the nuclear pore complex and nuclear import in mHtt expressing mammalian CAD neurons. PolyQ toxicity and cell cycle defects can be restored by enhancing RanGAP-mediated nuclear import, suggesting a potential therapeutic approach for this disease., Competing Interests: Madhu G Tapadia and Thomas E Lloyd reports financial support was provided by Department of Science and Technology (DST), New Delhi, Department of Biotechnology (DBT), New Delhi. 10.13039/100000002NIH grants R01NS094239 and R01AG068043 and the Packard Center for 10.13039/100018075ALS Research at 10.13039/100007880Johns Hopkins 10.13039/100008235School of Medicine. Madhu G Tapadia reports a relationship with Department of Science and Technology (DST), New Delhi and Department of Biotechnology (DBT) New Delhi that includes: funding grants. Thomas E Lloyd reports a relationship with 10.13039/100000002NIH grants R01NS094239 and R01AG068043 and the Packard Center for 10.13039/100018075ALS Research at 10.13039/100007880Johns Hopkins 10.13039/100008235School of Medicine that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)
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- 2024
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32. HIV-1 capsid shape, orientation, and entropic elasticity regulate translocation into the nuclear pore complex.
- Author
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Hudait A and Voth GA
- Subjects
- Humans, Nuclear Pore metabolism, Capsid Proteins genetics, Active Transport, Cell Nucleus, Nuclear Pore Complex Proteins metabolism, Translocation, Genetic, Elasticity, Capsid metabolism, HIV-1 genetics
- Abstract
Nuclear import and uncoating of the viral capsid are critical steps in the HIV-1 life cycle that serve to transport and release genomic material into the nucleus. Viral core import involves translocating the HIV-1 capsid at the nuclear pore complex (NPC). Notably, the central channel of the NPC appears to often accommodate and allow passage of intact HIV-1 capsid, though mechanistic details of the process remain to be fully understood. Here, we investigate the molecular interactions that operate in concert between the HIV-1 capsid and the NPC that regulate capsid translocation through the central channel. To this end, we develop a "bottom-up" coarse-grained (CG) model of the human NPC from recently released cryo-electron tomography structure and then construct composite membrane-embedded CG NPC models. We find that successful translocation from the cytoplasmic side to the NPC central channel is contingent on the compatibility of the capsid morphology and channel dimension and the proper orientation of the capsid approach to the channel from the cytoplasmic side. The translocation dynamics is driven by maximizing the contacts between phenylalanine-glycine nucleoporins at the central channel and the capsid. For the docked intact capsids, structural analysis reveals correlated striated patterns of lattice disorder likely related to the intrinsic capsid elasticity. Uncondensed genomic material inside the docked capsid augments the overall lattice disorder of the capsid. Our results suggest that the intrinsic "elasticity" can also aid the capsid to adapt to the stress and remain structurally intact during translocation., Competing Interests: Competing interests statement:The authors declare no competing interest.
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- 2024
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33. Mutations in nuclear pore complex promote osmotolerance in Arabidopsis by suppressing the nuclear translocation of ACQOS and its osmotically induced immunity.
- Author
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Mori K, Murakoshi Y, Tamura M, Kunitake S, Nishimura K, Ariga H, Tanaka K, Iuchi S, Yotsui I, Sakata Y, and Taji T
- Abstract
We have previously reported a wide variation in salt tolerance among Arabidopsis thaliana accessions and identified ACQOS , encoding a nucleotide-binding leucine-rich repeat (NLR) protein, as the causal gene responsible for the disturbance of acquired osmotolerance induced after mild salt stress. ACQOS is conserved among Arabidopsis osmosensitive accessions, including Col-0. In response to osmotic stress, it induces detrimental autoimmunity, resulting in suppression of osmotolerance, but how ACQOS triggers autoimmunity remains unclear. Here, we screened acquired osmotolerance ( aot ) mutants from EMS-mutagenized Col-0 seeds and isolated the aot19 mutant. In comparison with the wild type (WT), this mutant had acquired osmotolerance and decreased expression levels of pathogenesis-related genes. It had a mutation in a splicing acceptor site in NUCLEOPORIN 85 ( NUP85 ), which encodes a component of the nuclear pore complex. A mutant with a T-DNA insertion in NUP85 acquired osmotolerance similar to aot19. The WT gene complemented the osmotolerant phenotype of aot19 . We evaluated the acquired osmotolerance of five nup mutants of outer-ring NUP s and found that nup96 , nup107 , and aot19/nup85 , but not nup43 or nup133 , showed acquired osmotolerance. We examined the subcellular localization of the GFP-ACQOS protein and found that its nuclear translocation in response to osmotic stress was suppressed in aot19 . We suggest that NUP85 is essential for the nuclear translocation of ACQOS, and the loss-of-function mutation of NUP85 results in acquired osmotolerance by suppressing ACQOS-induced autoimmunity in response to osmotic stress., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Mori, Murakoshi, Tamura, Kunitake, Nishimura, Ariga, Tanaka, Iuchi, Yotsui, Sakata and Taji.)
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- 2024
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34. SUN1 facilitates CHMP7 nuclear influx and injury cascades in sporadic amyotrophic lateral sclerosis.
- Author
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Baskerville V, Rapuri S, Mehlhop E, and Coyne AN
- Subjects
- Humans, C9orf72 Protein genetics, C9orf72 Protein metabolism, Neurons metabolism, Membrane Proteins, Microtubule-Associated Proteins, Nuclear Proteins, Endosomal Sorting Complexes Required for Transport, Amyotrophic Lateral Sclerosis metabolism, Frontotemporal Dementia pathology, Pick Disease of the Brain
- Abstract
We have recently identified the aberrant nuclear accumulation of the ESCRT-III protein CHMP7 as an initiating event that leads to a significant injury to the nuclear pore complex (NPC) characterized by the reduction of specific nucleoporins from the neuronal NPC in sporadic amyotrophic lateral sclerosis (sALS) and C9orf72 ALS/frontotemporal dementia (FTD)-induced pluripotent stem cell-derived neurons (iPSNs), a phenomenon also observed in post-mortem patient tissues. Importantly, this NPC injury is sufficient to contribute to TDP-43 dysfunction and mislocalization, a common pathological hallmark of neurodegenerative diseases. However, the molecular mechanisms and events that give rise to increased nuclear translocation and/or retention of CHMP7 to initiate this pathophysiological cascade remain largely unknown. Here, using an iPSN model of sALS, we demonstrate that impaired NPC permeability barrier integrity and interactions with the LINC complex protein SUN1 facilitate CHMP7 nuclear localization and the subsequent 'activation' of NPC injury cascades. Collectively, our data provide mechanistic insights in the pathophysiological underpinnings of ALS/FTD and highlight SUN1 as a potent contributor to and modifier of CHMP7-mediated toxicity in sALS pathogenesis., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2024
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35. Imaging HIV-1 Nuclear Import, Uncoating, and Proviral Transcription.
- Author
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Burdick RC, Duchon A, Hu WS, and Pathak VK
- Subjects
- Humans, Virus Uncoating, Proviruses genetics, Proviruses physiology, Cell Nucleus metabolism, Cell Nucleus virology, HIV Infections virology, HIV Infections metabolism, Virion metabolism, Virion genetics, HIV-1 physiology, HIV-1 genetics, Active Transport, Cell Nucleus, Transcription, Genetic, Virus Replication
- Abstract
Live-cell imaging has become a powerful tool for dissecting the behavior of viral complexes during HIV-1 infection with high temporal and spatial resolution. Very few HIV-1 particles in a viral population are infectious and successfully complete replication (~1/50). Single-particle live-cell imaging enables the study of these rare infectious viral particles, which cannot be accomplished in biochemical assays that measure the average property of the entire viral population, most of which are not infectious. The timing and location of many events in the early stage of the HIV-1 life cycle, including nuclear import, uncoating, and integration, have only recently been elucidated. Live-cell imaging also provides a valuable approach to study interactions of viral and host factors in distinct cellular compartments and at specific stages of viral replication. Successful live-cell imaging experiments require careful consideration of the fluorescent labeling method used and avoid or minimize its potential impact on normal viral replication and produce misleading results. Ideally, it is beneficial to utilize multiple virus labeling strategies and compare the results to ensure that the virion labeling did not adversely influence the viral replication step that is under investigation. Another potential benefit of using different labeling strategies is that they can provide information about the state of the viral complexes. Here, we describe our methods that utilize multiple fluorescent protein labeling approaches to visualize and quantify important events in the HIV-1 life cycle, including docking HIV-1 particles with the nuclear envelope (NE) and their nuclear import, uncoating, and proviral transcription., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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36. Monitoring HIV-1 Nuclear Import Kinetics Using a Chemically Induced Nuclear Pore Blockade Assay.
- Author
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Dharan A and Campbell EM
- Subjects
- Humans, Kinetics, Cell Nucleus metabolism, HIV Infections virology, HIV Infections metabolism, Virus Integration, HIV-1 metabolism, HIV-1 physiology, Active Transport, Cell Nucleus, Nuclear Pore metabolism, Nuclear Pore Complex Proteins metabolism
- Abstract
To integrate with host chromatin and establish a productive infection, HIV-1 must translocate the viral Ribonucleoprotein (RNP) complex through the nuclear pore complex (NPC). Current assay to measure HIV-1 nuclear import relies on a transient byproduct of HIV-1 integration failure called 2-LTR circles. However, 2-LTR circles require complete or near-complete reverse transcription and association with the non-homologous end joining (NHEJ) machinery in the nucleus, which can complicate interpretation of 2-LTR circle formation as a measure of nuclear import kinetics. Here, we describe an approach to measure nuclear import of infectious HIV-1 particles. This involves chemically induced dimerization of Nup62, a central FG containing nucleoporin. Using this technique, nuclear import of infectious particles can be monitored in both primary and cell culture models. In response to host factor depletion or restriction factors, changes in HIV-1 nuclear import can be effectively measured using the nuclear import kinetics (NIK) assay., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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37. NUA positively regulates plant immunity by coordination with ESD4 to deSUMOylate TPR1 in Arabidopsis.
- Author
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Xie B, Luo M, Li Q, Shao J, Chen D, Somers DE, Tang D, and Shi H
- Subjects
- Gene Expression Regulation, Plant, Ligases metabolism, Nuclear Pore metabolism, Ubiquitin-Protein Ligases metabolism, Sumoylation, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Plant Immunity
- Abstract
Nuclear pore complex (NPC) is composed of multiple nucleoporins (Nups). A plethora of studies have highlighted the significance of NPC in plant immunity. However, the specific roles of individual Nups are poorly understood. NUCLEAR PORE ANCHOR (NUA) is a component of NPC. Loss of NUA leads to an increase in SUMO conjugates and pleiotropic developmental defects in Arabidopsis thaliana. Herein, we revealed that NUA is required for plant defense against multiple pathogens. NUCLEAR PORE ANCHOR associates with the transcriptional corepressor TOPLESS-RELATED1 (TPR1) and contributes to TPR1 deSUMOylation. Significantly, NUA-interacting protein EARLY IN SHORT DAYS 4 (ESD4), a SUMO protease, specifically deSUMOylates TPR1. It has been previously established that the SUMO E3 ligase SAP AND MIZ1 DOMAIN-CONTAINING LIGASE 1 (SIZ1)-mediated SUMOylation of TPR1 represses the immune-related function of TPR1. Consistent with this notion, the hyper-SUMOylated TPR1 in nua-3 leads to upregulated expression of TPR1 target genes and compromised TPR1-mediated disease resistance. Taken together, our work uncovers a mechanism by which NUA positively regulates plant defense responses by coordination with ESD4 to deSUMOylate TPR1. Our findings, together with previous studies, reveal a regulatory module in which SIZ1 and NUA/ESD4 control the homeostasis of TPR1 SUMOylation to maintain proper immune output., (© 2023 The Authors New Phytologist © 2023 New Phytologist Foundation.)
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- 2024
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38. Hard to handle: how lipid saturation affects the nuclear envelope.
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Höhne P and Bohnert M
- Subjects
- Humans, Endoplasmic Reticulum, Lipids, Nuclear Envelope, Nuclear Pore
- Abstract
The nuclear envelope is a unique subdomain of the endoplasmic reticulum (ER) that encapsulates the genome and mediates communication between the nucleus and the rest of the cell via nuclear pore complexes. A recent study by Romanauska and Köhler shows that balanced lipid unsaturation is critical for nuclear envelope and nuclear pore complex architecture and function., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
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- 2024
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39. Arabidopsis nucleoporin NUP96 mediates plant salt tolerance by modulating the transcription of salt-responsive genes.
- Author
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Yang X, Ji C, Liu X, Wei Z, Pang Q, and Zhang A
- Subjects
- Nuclear Pore Complex Proteins genetics, Nuclear Pore Complex Proteins metabolism, Salt Tolerance genetics, Plants genetics, Gene Expression Regulation, Plant, Stress, Physiological genetics, Plants, Genetically Modified genetics, Arabidopsis metabolism, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism
- Abstract
Main Conclusion: Physiological and molecular tests show that NUP96 plays an important role in the plant response to salt stress, resulting from the reprogramming of transcriptomic profiles, which are likely to be mediated by the influence on the nuclear/cytosol shuttling of the key regulators of salt tolerance. As a key component of the nuclear pore complex (NPC), nucleoporin 96 (NUP96) is critical for modulating plant development and interactions with environmental factors, but whether NUP96 is involved in the salt response is still unknown. Here, we analyzed the role of Arabidopsis NUP96 under salt stress. The loss-of-function mutant nup96 exhibited salt sensitivity in terms of rosette growth and root elongation, and showed attenuated capacity in maintaining ion and ROS homeostasis, which could be compensated for by the overexpression of NUP96. RNA sequencing revealed that many salt-responsive genes were misregulated after NUP96 mutation, and especially NUP96 is required for the expression of a large portion of salt-induced genes. This is likely correlated with the activity in facilitating nuclear/cytosol transport of the underlying regulators in salt tolerance such as the transcription factor ATAP2, targeted by eight downregulated genes in nup96 under salt stress. Our results illustrate that NUP96 plays an important role in the salt response, probably by regulating the nucleocytoplasmic shuttling of key mRNAs or proteins associated with plant salt responsiveness., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2023
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40. Nucleocytoplasmic transport rates are regulated by cellular processes that modulate GTP availability.
- Author
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Scott KL, Halfmann CT, Hoefakker AD, Purkayastha P, Wang TC, Lele TP, and Roux KJ
- Abstract
Nucleocytoplasmic transport (NCT), the facilitated diffusion of cargo molecules between the nucleus and cytoplasm through nuclear pore complexes (NPCs), enables numerous fundamental eukaryotic cellular processes. Ran GTPase uses cellular energy in the direct form of GTP to create a gradient across the nuclear envelope (NE) that drives the majority of NCT. We report here that changes in GTP availability resulting from altered cellular physiology modulate the rate of NCT, as monitored using synthetic and natural cargo, and the dynamics of Ran itself. Cell migration, cell spreading and/or modulation of the cytoskeleton or its connection to the nucleus alter GTP availability and thus rates of NCT, regulating RNA export and protein synthesis. These findings support a model in which changes in cellular physiology that alter GTP availability can regulate the rate of NCT, impacting fundamental cellular processes that extensively utilize NCT., Competing Interests: Declaration of interests The authors declare no competing interests. The authors declare no competing financial interests.
- Published
- 2023
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41. The Role of Nucleoporins in Cardiac Tissue Development and Disease.
- Author
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Chen X, Shi R, Luo Y, and Xu L
- Subjects
- Active Transport, Cell Nucleus physiology, Cryoelectron Microscopy, Cytoplasm metabolism, Nuclear Pore Complex Proteins analysis, Nuclear Pore Complex Proteins chemistry, Nuclear Pore Complex Proteins metabolism, Nuclear Pore chemistry, Nuclear Pore metabolism
- Abstract
Nuclear pore complexes (NPCs) are intricate intracellular structures composed of approximately 30 nuclear pore proteins (NUPs) that regulate the transport of materials between the nucleus and cytoplasm in eukaryotic cells. The heart is a crucial organ for sustaining the vital functions of the body, pumping blood rich in nutrients and energy to all organs and tissues. Recent studies have shown that NPCs play pivotal roles not only in normal cardiac physiological processes such as myocardial cell proliferation and differentiation but also in various pathological processes such as ischemic and hypoxic myocardial injury. Due to their mass and complicated nature, the structures of NPCs have been challenging to identify by the scientific community. With the development of cryo-electron microscopy and advanced sampling techniques, researchers have made significant progress in understanding the structures of NPCs. This review aims to summarize the latest research on the structural aspects of NPCs and their roles in cardiac physiology and pathology, increase the understanding of the intricate mechanisms of NPC actions, provide valuable insights into the pathogenesis of heart diseases and describe the development of potential novel therapeutic strategies., Competing Interests: The authors declare no conflict of interest., (© 2023 The Author(s). Published by IMR Press.)
- Published
- 2023
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42. Retroviral hijacking of host transport pathways for genome nuclear export.
- Author
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Behrens RT and Sherer NM
- Subjects
- Humans, Genome, Viral, Cell Nucleus virology, Cell Nucleus metabolism, Host Microbial Interactions, Host-Pathogen Interactions, Virus Replication, Animals, Active Transport, Cell Nucleus, Retroviridae genetics, Retroviridae physiology, Retroviridae metabolism
- Abstract
Recent advances in the study of virus-cell interactions have improved our understanding of how viruses that replicate their genomes in the nucleus (e.g., retroviruses, hepadnaviruses, herpesviruses, and a subset of RNA viruses) hijack cellular pathways to export these genomes to the cytoplasm where they access virion egress pathways. These findings shed light on novel aspects of viral life cycles relevant to the development of new antiviral strategies and can yield new tractable, virus-based tools for exposing additional secrets of the cell. The goal of this review is to summarize defined and emerging modes of virus-host interactions that drive the transit of viral genomes out of the nucleus across the nuclear envelope barrier, with an emphasis on retroviruses that are most extensively studied. In this context, we prioritize discussion of recent progress in understanding the trafficking and function of the human immunodeficiency virus type 1 Rev protein, exemplifying a relatively refined example of stepwise, cooperativity-driven viral subversion of multi-subunit host transport receptor complexes., Competing Interests: The authors declare no conflict of interest.
- Published
- 2023
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43. The scaffold nucleoporins SAR1 and SAR3 are essential for proper meiotic progression in Arabidopsis thaliana .
- Author
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Fernández-Jiménez N, Martinez-Garcia M, Varas J, Gil-Dones F, Santos JL, and Pradillo M
- Abstract
Nuclear Pore Complexes (NPCs) are embedded in the nuclear envelope (NE), regulating macromolecule transport and physically interacting with chromatin. The NE undergoes dramatic breakdown and reformation during plant cell division. In addition, this structure has a specific meiotic function, anchoring and positioning telomeres to facilitate the pairing of homologous chromosomes. To elucidate a possible function of the structural components of the NPCs in meiosis, we have characterized several Arabidopsis lines with mutations in genes encoding nucleoporins belonging to the outer ring complex. Plants defective for either SUPPRESSOR OF AUXIN RESISTANCE1 (SAR1, also called NUP160) or SAR3 (NUP96) present condensation abnormalities and SPO11-dependent chromosome fragmentation in a fraction of meiocytes, which is increased in the double mutant sar1 sar3 . We also observed these meiotic defects in mutants deficient in the outer ring complex protein HOS1, but not in mutants affected in other components of this complex. Furthermore, our findings may suggest defects in the structure of NPCs in sar1 and a potential link between the meiotic role of this nucleoporin and a component of the RUBylation pathway. These results provide the first insights in plants into the role of nucleoporins in meiotic chromosome behavior., Competing Interests: Author JV was employed by GlaxoSmithKline Spain. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer ODI declared a past coauthorship with the author MP to the handling editor., (Copyright © 2023 Fernández-Jiménez, Martinez-Garcia, Varas, Gil-Dones, Santos and Pradillo.)
- Published
- 2023
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44. Plant nuclear envelope as a hub connecting genome organization with regulation of gene expression.
- Author
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Tang Y
- Subjects
- Cell Nucleus, Chromatin genetics, Chromatin metabolism, Gene Expression Regulation, Plants genetics, Plants metabolism, Nuclear Envelope metabolism, Nuclear Pore genetics, Nuclear Pore metabolism
- Abstract
Eukaryotic cells organize their genome within the nucleus with a double-layered membrane structure termed the nuclear envelope (NE) as the physical barrier. The NE not only shields the nuclear genome but also spatially separates transcription from translation. Proteins of the NE including nucleoskeleton proteins, inner nuclear membrane proteins, and nuclear pore complexes have been implicated in interacting with underlying genome and chromatin regulators to establish a higher-order chromatin architecture. Here, I summarize recent advances in the knowledge of NE proteins that are involved in chromatin organization, gene regulation, and coordination of transcription and mRNA export. These studies support an emerging view of plant NE as a central hub that contributes to chromatin organization and gene expression in response to various cellular and environmental cues.
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- 2023
- Full Text
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45. Tpr Misregulation in Hippocampal Neural Stem Cells in Mouse Models of Alzheimer's Disease.
- Author
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Malik SC, Lin JD, Ziegler-Waldkirch S, Tholen S, Deshpande SS, Schwabenland M, Schilling O, Vlachos A, Meyer-Luehmann M, and Schachtrup C
- Subjects
- Animals, Humans, Mice, Chromatin metabolism, Disease Models, Animal, Nuclear Envelope metabolism, Alzheimer Disease metabolism, Hippocampus metabolism, Neural Stem Cells metabolism, Proto-Oncogene Proteins metabolism, Nuclear Pore Complex Proteins metabolism
- Abstract
Nuclear pore complexes (NPCs) are highly dynamic macromolecular protein structures that facilitate molecular exchange across the nuclear envelope. Aberrant NPC functioning has been implicated in neurodegeneration. The translocated promoter region (Tpr) is a critical scaffolding nucleoporin (Nup) of the nuclear basket, facing the interior of the NPC. However, the role of Tpr in adult neural stem/precursor cells (NSPCs) in Alzheimer's disease (AD) is unknown. Using super-resolution (SR) and electron microscopy, we defined the different subcellular localizations of Tpr and phospho-Tpr (P-Tpr) in NSPCs in vitro and in vivo. Elevated Tpr expression and reduced P-Tpr nuclear localization accompany NSPC differentiation along the neurogenic lineage. In 5xFAD mice, an animal model of AD, increased Tpr expression in DCX+ hippocampal neuroblasts precedes increased neurogenesis at an early stage, before the onset of amyloid-β plaque formation. Whereas nuclear basket Tpr interacts with chromatin modifiers and NSPC-related transcription factors, P-Tpr interacts and co-localizes with cyclin-dependent kinase 1 (Cdk1) at the nuclear chromatin of NSPCs. In hippocampal NSPCs in a mouse model of AD, aberrant Tpr expression was correlated with altered NPC morphology and counts, and Tpr was aberrantly expressed in postmortem human brain samples from patients with AD. Thus, we propose that altered levels and subcellular localization of Tpr in CNS disease affect Tpr functionality, which in turn regulates the architecture and number of NSPC NPCs, possibly leading to aberrant neurogenesis.
- Published
- 2023
- Full Text
- View/download PDF
46. Deviating from the norm: Nuclear organisation in trypanosomes.
- Author
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Field MC
- Subjects
- Evolution, Molecular, Nuclear Envelope metabolism, Nuclear Pore metabolism, Lamins metabolism, Cell Nucleus metabolism, Nuclear Lamina metabolism, Nuclear Pore Complex Proteins, Trypanosoma metabolism
- Abstract
At first glance the nucleus is a highly conserved organelle. Overall nuclear morphology, the octagonal nuclear pore complex, the presence of peripheral heterochromatin and the nuclear envelope appear near constant features right down to the ultrastructural level. New work is revealing significant compositional divergence within these nuclear structures and their associated functions, likely reflecting adaptations and distinct mechanisms between eukaryotic lineages and especially the trypanosomatids. While many examples of mechanistic divergence currently lack obvious functional interpretations, these studies underscore the malleability of nuclear architecture. I will discuss some recent findings highlighting these facets within trypanosomes, together with the underlying evolutionary framework and make a call for the exploration of nuclear function in non-canonical experimental organisms., Competing Interests: Declaration of competing interest The author declares that they have no known competing financial interests or personal relationships that could, have influenced the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2023
- Full Text
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47. A survey of the specificity and mechanism of 1,6 hexanediol-induced disruption of nuclear transport.
- Author
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Barrientos ECR, Otto TA, Mouton SN, Steen A, and Veenhoff LM
- Subjects
- Active Transport, Cell Nucleus, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, Cytoskeleton metabolism, Nuclear Pore metabolism, Nuclear Pore Complex Proteins metabolism, Karyopherins metabolism
- Abstract
Selective transport through the nuclear pore complex (NPC) depends on the dynamic binding of FG-repeat containing nucleoporins, the FG-nups, with each other and with Karyopherins (Kaps). Here, we assessed the specificity and mechanism by which the aliphatic alcohol 1,6-hexanediol (1,6HD) disrupts the permeability barrier of NPCs in live baker's yeast cells. After a 10-minute exposure to 5% 1,6HD, no notable changes were observed in cell growth, cytosolic pH and ATP levels, or the appearance of organelles. However, effects on the cytoskeleton and Hsp104 were noted. 1,6HD clearly affected the NPC permeability barrier, allowing passive nuclear entry of a 177kDa reporter protein that is normally confined to the cytosol. Moreover, multiple Kaps were displaced from NPCs, and the displacement of Kap122-GFP correlated with the observed passive permeability changes. 1,6HD thus temporarily permeates NPCs, and in line with Kap-centric models, the mechanism includes the release of numerous Kaps from the NPCs.
- Published
- 2023
- Full Text
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48. Rapid and inexpensive bedside diagnosis of RAN binding protein 2-associated acute necrotizing encephalopathy.
- Author
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Gouy B, Decorsière A, Desgraupes S, Duan W, Ouyang H, Wang YE, Yeh EA, Palazzo AF, Moraes TJ, Nisole S, and Arhel NJ
- Abstract
Acute necrotizing encephalopathy 1 (ANE1) is a very rare disorder associated with a dominant heterozygous mutation in the RANBP2 (RAN binding protein 2) gene. ANE1 is frequently triggered by a febrile infection and characterized by serious and irreversible neurological damage. Although only a few hundred cases have been reported, mutations in RANBP2 are only partially penetrant and can occur de novo , suggesting that their frequency may be higher in some populations. Genetic diagnosis is a lengthy process, potentially delaying definitive diagnosis. We therefore developed a rapid bedside qPCR-based tool for early diagnosis and screening of ANE1 mutations. Primers were designed to specifically assess RANBP2 and not RGPD (RANBP2 and GCC2 protein domains) and discriminate between wild-type or mutant RANBP2 . Nasal epithelial cells were obtained from two individuals with known RANBP2 mutations and two healthy control individuals. RANBP2 -specific reverse transcription followed by allele-specific primer qPCR amplification confirmed the specific detection of heterozygously expressed mutant RANBP2 in the ANE1 samples. This study demonstrates that allele-specific qPCR can be used as a rapid and inexpensive diagnostic tool for ANE1 using preexisting equipment at local hospitals. It can also be used to screen non-hospitalized family members and at risk-population to better establish the frequency of non-ANE-associated RANBP2 mutations, as well as possible tissue-dependent expression patterns., Systematic Review Registration: The protocol was registered in the international prospective register of systematic reviews (PROSPERO- CRD42023443257)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Gouy, Decorsière, Desgraupes, Duan, Ouyang, Wang, Yeh, Palazzo, Moraes, Nisole and Arhel.)
- Published
- 2023
- Full Text
- View/download PDF
49. From the sideline: Tissue-specific nucleoporin function in health and disease, an update.
- Author
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Jühlen R and Fahrenkrog B
- Subjects
- Humans, Active Transport, Cell Nucleus, Nuclear Pore metabolism, Mutation, Nuclear Pore Complex Proteins genetics, Nuclear Pore Complex Proteins metabolism, Neoplasms metabolism
- Abstract
The subcellular compartmentalisation of eukaryotic cells requires selective exchange between the cytoplasm and the nucleus. Intact nucleocytoplasmic transport is vital for normal cell function and mutations in the executing machinery have been causally linked to human disease. Central players in nucleocytoplasmic exchange are nuclear pore complexes (NPCs), which are built from ~30 distinct proteins collectively termed nucleoporins. Aberrant nucleoporin expression was detected in human cancers and autoimmune diseases since quite some time, while it was through the increasing use of next generation sequencing that mutations in nucleoporin genes associated with mainly rare hereditary diseases were revealed. The number of newly identified mutations is steadily increasing, as is the number of diseases. Mutational hotspots have emerged: mutations in the scaffold nucleoporins seemingly affect primarily inner organs, such as heart, kidney, and ovaries, whereas genetic alterations in peripheral, cytoplasmic nucleoporins affect primarily the central nervous system and development. In this review, we summarise latest insights on altered nucleoporin function in the context of human hereditary disorders, with a focus on those where mechanistic insights are beginning to emerge., (© 2023 Federation of European Biochemical Societies.)
- Published
- 2023
- Full Text
- View/download PDF
50. Autophagy as a caretaker of nuclear integrity.
- Author
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Boyle E and Wilfling F
- Subjects
- Rats, Humans, Animals, Nuclear Pore Complex Proteins metabolism, Cell Nucleus metabolism, Saccharomyces cerevisiae metabolism, Autophagy, Mammals metabolism, Caenorhabditis elegans metabolism, Nuclear Pore metabolism
- Abstract
Due to their essential functions, dysregulation of nuclear pore complexes (NPCs) is strongly associated with numerous human diseases, including neurodegeneration and cancer. On a cellular level, longevity of scaffold nucleoporins in postmitotic cells of both C. elegans and mammals renders them vulnerable to age-related damage, which is associated with an increase in pore leakiness and accumulation of intranuclear aggregates in rat brain cells. Thus, understanding the mechanisms which underpin the homeostasis of this complex, as well as other nuclear proteins, is essential. In this review, autophagy-mediated degradation pathways governing nuclear components in yeast will be discussed, with a particular focus on NPCs. Furthermore, the various nuclear degradation mechanisms identified thus far in diverse eukaryotes will also be highlighted., (© 2023 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)
- Published
- 2023
- Full Text
- View/download PDF
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