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Nature Reviews. Molecular Cell Biology May 2022Efficient and regulated nucleocytoplasmic trafficking of macromolecules to the correct subcellular compartment is critical for proper functions of the eukaryotic cell.... (Review)
Review
Efficient and regulated nucleocytoplasmic trafficking of macromolecules to the correct subcellular compartment is critical for proper functions of the eukaryotic cell. The majority of the macromolecular traffic across the nuclear pores is mediated by the Karyopherin-β (or Kap) family of nuclear transport receptors. Work over more than two decades has shed considerable light on how the different Kap family members bring their respective cargoes into the nucleus or the cytoplasm in efficient and highly regulated manners. In this Review, we overview the main features and established functions of Kap family members, describe how Kaps recognize their cargoes and discuss the different ways in which these Kap-cargo interactions can be regulated, highlighting new findings and open questions. We also describe current knowledge of the import and export of the components of three large gene expression machines - the core replisome, RNA polymerase II and the ribosome - pointing out the questions that persist about how such large macromolecular complexes are trafficked to serve their function in a designated subcellular location.
Topics: Active Transport, Cell Nucleus; Cell Nucleus; Karyopherins; Nuclear Pore; Receptors, Cytoplasmic and Nuclear; beta Karyopherins
PubMed: 35058649
DOI: 10.1038/s41580-021-00446-7 -
Cell May 2018Defects in nucleocytoplasmic transport have been identified as a key pathogenic event in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) mediated...
Defects in nucleocytoplasmic transport have been identified as a key pathogenic event in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) mediated by a GGGGCC hexanucleotide repeat expansion in C9ORF72, the most common genetic cause of ALS/FTD. Furthermore, nucleocytoplasmic transport disruption has also been implicated in other neurodegenerative diseases with protein aggregation, suggesting a shared mechanism by which protein stress disrupts nucleocytoplasmic transport. Here, we show that cellular stress disrupts nucleocytoplasmic transport by localizing critical nucleocytoplasmic transport factors into stress granules, RNA/protein complexes that play a crucial role in ALS pathogenesis. Importantly, inhibiting stress granule assembly, such as by knocking down Ataxin-2, suppresses nucleocytoplasmic transport defects as well as neurodegeneration in C9ORF72-mediated ALS/FTD. Our findings identify a link between stress granule assembly and nucleocytoplasmic transport, two fundamental cellular processes implicated in the pathogenesis of C9ORF72-mediated ALS/FTD and other neurodegenerative diseases.
Topics: Active Transport, Cell Nucleus; Aged; Amyotrophic Lateral Sclerosis; Arsenites; Ataxin-2; C9orf72 Protein; DNA Repeat Expansion; Female; Frontotemporal Dementia; HEK293 Cells; Humans; Male; Membrane Glycoproteins; Middle Aged; Nuclear Pore Complex Proteins; Oxidative Stress; RNA Interference; RNA, Small Interfering; Sodium Compounds; alpha Karyopherins; beta Karyopherins; ran GTP-Binding Protein
PubMed: 29628143
DOI: 10.1016/j.cell.2018.03.025 -
Annual Review of Biochemistry Jun 2019The nuclear pore complex (NPC) serves as the sole bidirectional gateway of macromolecules in and out of the nucleus. Owing to its size and complexity (∼1,000 protein... (Review)
Review
The nuclear pore complex (NPC) serves as the sole bidirectional gateway of macromolecules in and out of the nucleus. Owing to its size and complexity (∼1,000 protein subunits, ∼110 MDa in humans), the NPC has remained one of the foremost challenges for structure determination. Structural studies have now provided atomic-resolution crystal structures of most nucleoporins. The acquisition of these structures, combined with biochemical reconstitution experiments, cross-linking mass spectrometry, and cryo-electron tomography, has facilitated the determination of the near-atomic overall architecture of the symmetric core of the human, fungal, and algal NPCs. Here, we discuss the insights gained from these new advances and outstanding issues regarding NPC structure and function. The powerful combination of bottom-up and top-down approaches toward determining the structure of the NPC offers a paradigm for uncovering the architectures of other complex biological machines to near-atomic resolution.
Topics: Active Transport, Cell Nucleus; Animals; Cell Nucleus; Cryoelectron Microscopy; Crystallography, X-Ray; Eukaryota; Humans; Models, Molecular; Nuclear Pore; Nuclear Pore Complex Proteins; Protein Conformation; Protein Subunits; RNA, Messenger
PubMed: 30883195
DOI: 10.1146/annurev-biochem-062917-011901 -
Nature Neuroscience Feb 2018The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and...
The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD). However, the composition of aggregates and their contribution to the disease process remain unknown. Here we used proximity-dependent biotin identification (BioID) to interrogate the interactome of detergent-insoluble TDP-43 aggregates and found them enriched for components of the nuclear pore complex and nucleocytoplasmic transport machinery. Aggregated and disease-linked mutant TDP-43 triggered the sequestration and/or mislocalization of nucleoporins and transport factors, and interfered with nuclear protein import and RNA export in mouse primary cortical neurons, human fibroblasts and induced pluripotent stem cell-derived neurons. Nuclear pore pathology is present in brain tissue in cases of sporadic ALS and those involving genetic mutations in TARDBP and C9orf72. Our data strongly implicate TDP-43-mediated nucleocytoplasmic transport defects as a common disease mechanism in ALS/FTD.
Topics: Active Transport, Cell Nucleus; Amyotrophic Lateral Sclerosis; Animals; Animals, Genetically Modified; C9orf72 Protein; Cells, Cultured; Cerebral Cortex; DNA-Binding Proteins; Drosophila; Drosophila Proteins; Embryo, Nonmammalian; Female; Frontotemporal Dementia; Humans; Larva; Male; Mice; Mice, Inbred C57BL; Neuroblastoma; Nuclear Envelope; Nuclear Pore; Protein Aggregation, Pathological
PubMed: 29311743
DOI: 10.1038/s41593-017-0047-3 -
Nature Cell Biology Jun 2022Mechanical force controls fundamental cellular processes in health and disease, and increasing evidence shows that the nucleus both experiences and senses applied...
Mechanical force controls fundamental cellular processes in health and disease, and increasing evidence shows that the nucleus both experiences and senses applied forces. Such forces can lead to the nuclear translocation of proteins, but whether force controls nucleocytoplasmic transport, and how, remains unknown. Here we show that nuclear forces differentially control passive and facilitated nucleocytoplasmic transport, setting the rules for the mechanosensitivity of shuttling proteins. We demonstrate that nuclear force increases permeability across nuclear pore complexes, with a dependence on molecular weight that is stronger for passive than for facilitated diffusion. Owing to this differential effect, force leads to the translocation of cargoes into or out of the nucleus within a given range of molecular weight and affinity for nuclear transport receptors. Further, we show that the mechanosensitivity of several transcriptional regulators can be both explained by this mechanism and engineered exogenously by introducing appropriate nuclear localization signals. Our work unveils a mechanism of mechanically induced signalling, probably operating in parallel with others, with potential applicability across signalling pathways.
Topics: Active Transport, Cell Nucleus; Cell Nucleus; Nuclear Pore; Protein Transport; Receptors, Cytoplasmic and Nuclear
PubMed: 35681009
DOI: 10.1038/s41556-022-00927-7 -
Biochemical Society Transactions Dec 2020Nucleoporins (Nups) represent a range of proteins most known for composing the macromolecular assembly of the nuclear pore complex (NPC). Among them, the family of... (Review)
Review
Nucleoporins (Nups) represent a range of proteins most known for composing the macromolecular assembly of the nuclear pore complex (NPC). Among them, the family of intrinsically disordered proteins (IDPs) phenylalanine-glycine (FG) rich Nups, form the permeability barrier and coordinate the high-speed nucleocytoplasmic transport in a selective way. Those FG-Nups have been demonstrated to participate in various biological processes besides nucleocytoplasmic transport. The high number of accessible hydrophobic motifs of FG-Nups potentially gives rise to this multifunctionality, enabling them to form unique microenvironments. In this review, we discuss the multifunctionality of disordered and F-rich Nups and the diversity of their localizations, emphasizing the important roles of those Nups in various regulatory and metabolic processes.
Topics: Active Transport, Cell Nucleus; Amino Acid Motifs; Animals; Cell Lineage; Cell Nucleus; Cilia; Cytoplasm; DNA Repair; Gene Expression Regulation; Glycine; Humans; Hydrophobic and Hydrophilic Interactions; Intrinsically Disordered Proteins; Neurodegenerative Diseases; Nuclear Pore; Nuclear Pore Complex Proteins; Phenylalanine; Protein Folding; Protein Transport
PubMed: 33336681
DOI: 10.1042/BST20200357 -
Methods in Molecular Biology (Clifton,... 2022The process of eukaryotic ribosome assembly stretches across the nucleolus, the nucleoplasm and the cytoplasm, and therefore relies on efficient nucleocytoplasmic...
The process of eukaryotic ribosome assembly stretches across the nucleolus, the nucleoplasm and the cytoplasm, and therefore relies on efficient nucleocytoplasmic transport. In yeast, the import machinery delivers ~140,000 ribosomal proteins every minute to the nucleus for ribosome assembly. At the same time, the export machinery facilitates translocation of ~2000 pre-ribosomal particles every minute through ~200 nuclear pore complexes (NPC) into the cytoplasm. Eukaryotic ribosome assembly also requires >200 conserved assembly factors, which transiently associate with pre-ribosomal particles. Their site(s) of action on maturing pre-ribosomes are beginning to be elucidated. In this chapter, we outline protocols that enable rapid biochemical isolation of pre-ribosomal particles for single particle cryo-electron microscopy (cryo-EM) and in vitro reconstitution of nuclear transport processes. We discuss cell-biological and genetic approaches to investigate how the ribosome assembly and the nucleocytoplasmic transport machineries collaborate to produce functional ribosomes.
Topics: Active Transport, Cell Nucleus; Cryoelectron Microscopy; Ribosomal Proteins; Ribosomes; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 35796985
DOI: 10.1007/978-1-0716-2501-9_7 -
Neurotherapeutics : the Journal of the... Jul 2022The nuclear pore complex (NPC) is a large multimeric structure that is interspersed throughout the membrane of the nucleus and consists of at least 33 protein... (Review)
Review
The nuclear pore complex (NPC) is a large multimeric structure that is interspersed throughout the membrane of the nucleus and consists of at least 33 protein components. Individual components cooperate within the nuclear pore to facilitate selective passage of materials between the nucleus and cytoplasm while simultaneously performing pore-independent roles throughout the cell. NPC dysfunction is a hallmark of neurodegenerative disorders including Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis (ALS). NPC components can become mislocalized or altered in expression in neurodegeneration. These alterations in NPC structure are often detrimental to the neuronal function and ultimately lead to neuronal loss. This review highlights the importance of nucleocytoplasmic transport and NPC integrity and how dysfunction of such may contribute to neurodegeneration.
Topics: Humans; Nuclear Pore; Active Transport, Cell Nucleus; Amyotrophic Lateral Sclerosis; Cytoplasm; Cell Nucleus
PubMed: 36070178
DOI: 10.1007/s13311-022-01293-w -
International Journal of Molecular... Apr 2021Nucleocytoplasmic transport (NCT) across the nuclear envelope is precisely regulated in eukaryotic cells, and it plays critical roles in maintenance of cellular... (Review)
Review
Nucleocytoplasmic transport (NCT) across the nuclear envelope is precisely regulated in eukaryotic cells, and it plays critical roles in maintenance of cellular homeostasis. Accumulating evidence has demonstrated that dysregulations of NCT are implicated in aging and age-related neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer's disease (AD), and Huntington disease (HD). This is an emerging research field. The molecular mechanisms underlying impaired NCT and the pathogenesis leading to neurodegeneration are not clear. In this review, we comprehensively described the components of NCT machinery, including nuclear envelope (NE), nuclear pore complex (NPC), importins and exportins, RanGTPase and its regulators, and the regulatory mechanisms of nuclear transport of both protein and transcript cargos. Additionally, we discussed the possible molecular mechanisms of impaired NCT underlying aging and neurodegenerative diseases, such as ALS/FTD, HD, and AD.
Topics: Active Transport, Cell Nucleus; Aging; Animals; Humans; Neurodegenerative Diseases; Nuclear Pore
PubMed: 33920577
DOI: 10.3390/ijms22084165 -
Nature Reviews. Neurology Jun 2022The genetic underpinnings and end-stage pathological hallmarks of neurodegenerative diseases are increasingly well defined, but the cellular pathophysiology of disease... (Review)
Review
The genetic underpinnings and end-stage pathological hallmarks of neurodegenerative diseases are increasingly well defined, but the cellular pathophysiology of disease initiation and propagation remains poorly understood, especially in sporadic forms of these diseases. Altered nucleocytoplasmic transport is emerging as a prominent pathomechanism of multiple neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer disease, frontotemporal dementia and Huntington disease. The nuclear pore complex (NPC) and interactions between its individual nucleoporin components and nuclear transport receptors regulate nucleocytoplasmic transport, as well as genome organization and gene expression. Specific nucleoporin abnormalities have been identified in sporadic and familial forms of neurodegenerative disease, and these alterations are thought to contribute to disrupted nucleocytoplasmic transport. The specific nucleoporins and nucleocytoplasmic transport proteins that have been linked to different neurodegenerative diseases are partially distinct, suggesting that NPC injury contributes to the cellular specificity of neurodegenerative disease and could be an early initiator of the pathophysiological cascades that underlie neurodegenerative disease. This concept is consistent with the fact that rare genetic mutations in some nucleoporins cause cell-type-specific neurological disease. In this Review, we discuss nucleoporin and NPC disruptions and consider their impact on cellular function and the pathophysiology of neurodegenerative disease.
Topics: Active Transport, Cell Nucleus; Frontotemporal Dementia; Humans; Neurodegenerative Diseases; Nuclear Pore; Nuclear Pore Complex Proteins
PubMed: 35488039
DOI: 10.1038/s41582-022-00653-6