The Experts below are selected from a list of 23634 Experts worldwide ranked by ideXlab platform
Michael P Rout - One of the best experts on this subject based on the ideXlab platform.
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The Nuclear Pore complex and Nuclear transport.
Cold Spring Harbor perspectives in biology, 2010Co-Authors: Susan R Wente, Michael P RoutAbstract:Internal membrane bound structures sequester all genetic material in eukaryotic cells. The most prominent of these structures is the nucleus, which is bounded by a double membrane termed the Nuclear envelope (NE). Though this NE separates the nucleoplasm and genetic material within the nucleus from the surrounding cytoplasm, it is studded throughout with portals called Nuclear Pore complexes (NPCs). The NPC is a highly selective, bidirectional transporter for a tremendous range of protein and ribonucleoprotein cargoes. All the while the NPC must prevent the passage of nonspecific macromolecules, yet allow the free diffusion of water, sugars, and ions. These many types of Nuclear transport are regulated at multiple stages, and the NPC carries binding sites for many of the proteins that modulate and modify the cargoes as they pass across the NE. Assembly, maintenance, and repair of the NPC must somehow occur while maintaining the integrity of the NE. Finally, the NPC appears to be an anchor for localization of many Nuclear processes, including gene activation and cell cycle regulation. All these requirements demonstrate the complex design of the NPC and the integral role it plays in key cellular processes.
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The Nuclear Pore complex: bridging Nuclear transport and gene regulation
Nature Reviews Molecular Cell Biology, 2010Co-Authors: Caterina Strambio-de-castillia, Mario Niepel, Michael P RoutAbstract:The Nuclear Pore complex is the key regulator of transport between the cytoplasm and nucleus. Emerging evidence suggests it also regulates gene expression by influencing the internal architecture of the nucleus and by coordinating the delivery of genetic information to the cytoplasmic protein synthesis machinery. Although the Nuclear Pore complex (NPC) is best known for its primary function as the key regulator of molecular traffic between the cytoplasm and the nucleus, a growing body of experimental evidence suggests that this structure participates in a considerably broader range of cellular activities on both sides of the Nuclear envelope. Indeed, the NPC is emerging as an important regulator of gene expression through its influence on the internal architectural organization of the nucleus and its apparently extensive involvement in coordinating the seamless delivery of genetic information to the cytoplasmic protein synthesis machinery.
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Components of coated vesicles and Nuclear Pore complexes share a common molecular architecture.
PLoS Biology, 2004Co-Authors: Damien P. Devos, Brian T Chait, Svetlana Dokudovskaya, Frank Alber, Rosemary Williams, Andrej Sali, Michael P RoutAbstract:Numerous features distinguish prokaryotes from eukaryotes, chief among which are the distinctive internal membrane systems of eukaryotic cells. These membrane systems form elaborate compartments and vesicular trafficking pathways, and sequester the chromatin within the Nuclear envelope. The Nuclear Pore complex is the portal that specifically mediates macromolecular trafficking across the Nuclear envelope. Although it is generally understood that these internal membrane systems evolved from specialized invaginations of the prokaryotic plasma membrane, it is not clear how the Nuclear Pore complex could have evolved from organisms with no analogous transport system. Here we use computational and biochemical methods to perform a structural analysis of the seven proteins comprising the yNup84/vNup107-160 subcomplex, a core building block of the Nuclear Pore complex. Our analysis indicates that all seven proteins contain either a beta-propeller fold, an alpha-solenoid fold, or a distinctive arrangement of both, revealing close similarities between the structures comprising the yNup84/vNup107-160 subcomplex and those comprising the major types of vesicle coating complexes that maintain vesicular trafficking pathways. These similarities suggest a common evolutionary origin for Nuclear Pore complexes and coated vesicles in an early membrane-curving module that led to the formation of the internal membrane systems in modern eukaryotes.
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the yeast Nuclear Pore complex composition architecture and transport mechanism
Journal of Cell Biology, 2000Co-Authors: Michael P Rout, John D Aitchison, Adisetyantari Suprapto, Kelly Hjertaas, Yingming Zhao, Brian T ChaitAbstract:An understanding of how the Nuclear Pore complex (NPC) mediates nucleocytoplasmic exchange requires a comprehensive inventory of the molecular components of the NPC and a knowledge of how each component contributes to the overall structure of this large molecular translocation machine. Therefore, we have taken a comprehensive approach to classify all components of the yeast NPC (nucleoporins). This involved identifying all the proteins present in a highly enriched NPC fraction, determining which of these proteins were nucleoporins, and localizing each nucleoporin within the NPC. Using these data, we present a map of the molecular architecture of the yeast NPC and provide evidence for a Brownian affinity gating mechanism for nucleocytoplasmic transport.
Martin Beck - One of the best experts on this subject based on the ideXlab platform.
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3d super resolution fluorescence microscopy maps the variable molecular architecture of the Nuclear Pore complex
Molecular Biology of the Cell, 2021Co-Authors: Vilma Jimenez Sabinina, Shyamal Mosalaganti, Julius M Hossain, Jeankarim Heriche, Philipp Hoess, Bianca Nijmeijer, Moritz Kueblbeck, Andrea Callegari, Anna Szymborska, Martin BeckAbstract:Nuclear Pore complexes (NPCs) are large macromolecular machines that mediate the traffic between the nucleus and the cytoplasm. In vertebrates, each NPC consists of ∼1000 proteins, termed nucleopor...
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selective autophagy degrades Nuclear Pore complexes
Nature Cell Biology, 2020Co-Authors: Florian Wilfling, Martin Beck, Paolo Ronchi, Matteo Allegretti, Shyamal Mosalaganti, Stefan Jentsch, Boris PfanderAbstract:Nuclear Pore complexes (NPCs) are very large proteinaceous assemblies that consist of more than 500 individual proteins1,2. NPCs are essential for nucleocytoplasmic transport of different cellular components, and disruption of the integrity of NPCs has been linked to aging, cancer and neurodegenerative diseases3–7. However, the mechanism by which membrane-embedded NPCs are turned over is currently unknown. Here we show that, after nitrogen starvation or genetic interference with the architecture of NPCs, nucleoporins are rapidly degraded in the budding yeast Saccharomyces cerevisiae. We demonstrate that NPC turnover involves vacuolar proteases and the core autophagy machinery. Autophagic degradation is mediated by the cytoplasmically exposed Nup159, which serves as intrinsic cargo receptor and directly binds to the autophagy marker protein Atg8. Autophagic degradation of NPCs is therefore inducible, enabling the removal of individual NPCs from the Nuclear envelope. Lee et al. show that, after nitrogen starvation and genetic interference with the architecture of Nuclear Pore complexes, nucleoporins are degraded by autophagy, constituting a quality-control step at the Nuclear envelope.
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Structure and Assembly of the Nuclear Pore Complex
Annual Review of Biophysics, 2019Co-Authors: Bernhard Hampoelz, Panagiotis L Kastritis, Amparo Andres-pons, Martin BeckAbstract:Nuclear Pore complexes (NPCs) mediate nucleocytoplasmic exchange. They are exceptionally large protein complexes that fuse the inner and outer Nuclear membranes to form channels across the Nuclear envelope. About 30 different protein components, termed nucleoporins, assemble in multiple copies into an intricate cylindrical architecture. Here, we review our current knowledge of the structure of nucleoporins and how those come together in situ. We delineate architectural principles on several hierarchical organization levels, including isoforms, posttranslational modifications, nucleoporins, and higher-order oligomerization of nucleoporin subcomplexes. We discuss how cells exploit this modularity to faithfully assemble NPCs.
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the Nuclear Pore complex understanding its function through structural insight
Nature Reviews Molecular Cell Biology, 2017Co-Authors: Martin Beck, Ed HurtAbstract:Nuclear Pore complexes (NPCs) are large protein assemblies that form channels in the Nuclear envelope and constitute major routes for nucleocytoplasmic communication. Insights into the complex structure of NPCs provide the basis for understanding their functions and reveal how the dysfunction of their structural components, nucleoporins, contributes to human disease.
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snapshots of Nuclear Pore complexes in action captured by cryo electron tomography
Nature, 2007Co-Authors: Martin Beck, Wolfgang Baumeister, Vladan Lucic, Friedrich Forster, Ohad MedaliaAbstract:Nuclear Pore complexes reside in the Nuclear envelope of eukaryotic cells and mediate the nucleocytoplasmic exchange of macromolecules. Traffic is regulated by mobile transport receptors that target their cargo to the central translocation channel, where phenylalanine-glycine-rich repeats serve as binding sites. The structural analysis of the Nuclear Pore is a formidable challenge given its size, its location in a membranous environment and its dynamic nature. Here we have used cryo-electron tomography to study the structure of Nuclear Pore complexes in their functional environment, that is, in intact nuclei of Dictyostelium discoideum. A new image-processing strategy compensating for deviations of the asymmetric units (protomers) from a perfect eight-fold symmetry enabled us to refine the structure and to identify new features. Furthermore, the superposition of a large number of tomograms taken in the presence of cargo, which was rendered visible by gold nanoparticles, has yielded a map outlining the trajectories of import cargo. Finally, we have performed single-molecule Monte Carlo simulations of Nuclear import to interpret the experimentally observed cargo distribution in the light of existing models for Nuclear import.
Susan R Wente - One of the best experts on this subject based on the ideXlab platform.
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1The mRNA export factor human Gle1 interacts with the Nuclear Pore complex protein
2016Co-Authors: Heidi J. Rayala, Frederic Kendirgi, Dianne M. Barry, Philip W. Majerus, Susan R WenteAbstract:Kap, karyopherin; kbp, kilo-base pairs; GFP, green fluorescence protein; GST, glutathione S-transferase; MBP, maltose-binding protein; h, human; hnRNP, heterogeneous Nuclear ribonucleoprotein; m, messenger; mRNP, messenger RNA-bound hnRNP complex; NE; Nuclear envelope; NES, Nuclear export sequence; NLS, Nuclear localization sequence; NPC, Nuclear Pore complex; sc, S. cerevisiae; GBD, Gal4 DNA binding domain; GAD, Gal4 transcativation domain
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The Nuclear Pore complex and Nuclear transport.
Cold Spring Harbor perspectives in biology, 2010Co-Authors: Susan R Wente, Michael P RoutAbstract:Internal membrane bound structures sequester all genetic material in eukaryotic cells. The most prominent of these structures is the nucleus, which is bounded by a double membrane termed the Nuclear envelope (NE). Though this NE separates the nucleoplasm and genetic material within the nucleus from the surrounding cytoplasm, it is studded throughout with portals called Nuclear Pore complexes (NPCs). The NPC is a highly selective, bidirectional transporter for a tremendous range of protein and ribonucleoprotein cargoes. All the while the NPC must prevent the passage of nonspecific macromolecules, yet allow the free diffusion of water, sugars, and ions. These many types of Nuclear transport are regulated at multiple stages, and the NPC carries binding sites for many of the proteins that modulate and modify the cargoes as they pass across the NE. Assembly, maintenance, and repair of the NPC must somehow occur while maintaining the integrity of the NE. Finally, the NPC appears to be an anchor for localization of many Nuclear processes, including gene activation and cell cycle regulation. All these requirements demonstrate the complex design of the NPC and the integral role it plays in key cellular processes.
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peering through the Pore Nuclear Pore complex structure assembly and function
Developmental Cell, 2003Co-Authors: Mythili Suntharalingam, Susan R WenteAbstract:Nuclear Pore complexes (NPCs) are large proteinaceous assemblies that provide the only known portals for exchanging macromolecules between the nucleus and cytoplasm. This includes the movement of small molecules and the selective, facilitated transport of large proteins and RNAs. Faithful, continuous NPC assembly is key for maintaining normal physiological function and is closely tied to proper cell division. This review focuses on the most outstanding issues involving NPC structure, assembly, and function.
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the Nuclear Pore complex a protein machine bridging the nucleus and cytoplasm
Current Opinion in Cell Biology, 2000Co-Authors: Kathryn J Ryan, Susan R WenteAbstract:Compositional analysis of Nuclear Pore complexes (NPCs) is nearing completion, and efforts are now focused on understanding how these protein machines work. Recent analysis of soluble transport factor interactions with NPC proteins reveals distinct and overlapping pathways for movement between the nucleus and cytoplasm. New fluorescence- and microscopy-based strategies have been used to monitor the pathway of NPC assembly and to reveal the dynamics of the NPC during transport.
Benjamin Vollmer - One of the best experts on this subject based on the ideXlab platform.
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in situ structural analysis of the human Nuclear Pore complex
Nature, 2015Co-Authors: Alexander Von Appen, Jan Kosinski, Lenore Sparks, Amanda L Diguilio, Benjamin Vollmer, Marietherese Mackmull, Niccolo Banterle, Luca Parca, Panagiotis L KastritisAbstract:The most comprehensive architectural model to date of the Nuclear Pore complex reveals previously unknown local interactions, and a role for nucleoporin 358 in Y-complex oligomerization. The transport of materials between the nucleus and cytoplasm in eukaryotic cells is controlled by the Nuclear Pore complex. Martin Beck and colleagues have used cryo-electron tomography, mass spectrometry and other analyses to generate the most comprehensive architectural model of the human Nuclear Pore complex to date. The model reveals previously unknown local interactions, and a role for the transport channel nucleoporin 358 (Nup358) in mediating oligomerization of the Y-complex within the Nuclear Pore complex. Nuclear Pore complexes are fundamental components of all eukaryotic cells that mediate nucleocytoplasmic exchange. Determining their 110-megadalton structure imposes a formidable challenge and requires in situ structural biology approaches. Of approximately 30 nucleoporins (Nups), 15 are structured and form the Y and inner-ring complexes. These two major scaffolding modules assemble in multiple copies into an eight-fold rotationally symmetric structure that fuses the inner and outer Nuclear membranes to form a central channel of ~60 nm in diameter1. The scaffold is decorated with transport-channel Nups that often contain phenylalanine-repeat sequences and mediate the interaction with cargo complexes. Although the architectural arrangement of parts of the Y complex has been elucidated, it is unclear how exactly it oligomerizes in situ. Here we combine cryo-electron tomography with mass spectrometry, biochemical analysis, perturbation experiments and structural modelling to generate, to our knowledge, the most comprehensive architectural model of the human Nuclear Pore complex to date. Our data suggest previously unknown protein interfaces across Y complexes and to inner-ring complex members. We show that the transport-channel Nup358 (also known as Ranbp2) has a previously unanticipated role in Y-complex oligomerization. Our findings blur the established boundaries between scaffold and transport-channel Nups. We conclude that, similar to coated vesicles, several copies of the same structural building block—although compositionally identical—engage in different local sets of interactions and conformations.
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in situ structural analysis of the human Nuclear Pore complex
Nature, 2015Co-Authors: Alexander Von Appen, Jan Kosinski, Lenore Sparks, Amanda L Diguilio, Benjamin Vollmer, Marietherese Mackmull, Niccolo Banterle, Alessandro Ori, Luca ParcaAbstract:Nuclear Pore complexes are fundamental components of all eukaryotic cells that mediate nucleocytoplasmic exchange. Determining their 110-megadalton structure imposes a formidable challenge and requires in situ structural biology approaches. Of approximately 30 nucleoporins (Nups), 15 are structured and form the Y and inner-ring complexes. These two major scaffolding modules assemble in multiple copies into an eight-fold rotationally symmetric structure that fuses the inner and outer Nuclear membranes to form a central channel of ~60 nm in diameter. The scaffold is decorated with transport-channel Nups that often contain phenylalanine-repeat sequences and mediate the interaction with cargo complexes. Although the architectural arrangement of parts of the Y complex has been elucidated, it is unclear how exactly it oligomerizes in situ. Here we combine cryo-electron tomography with mass spectrometry, biochemical analysis, perturbation experiments and structural modelling to generate, to our knowledge, the most comprehensive architectural model of the human Nuclear Pore complex to date. Our data suggest previously unknown protein interfaces across Y complexes and to inner-ring complex members. We show that the transport-channel Nup358 (also known as Ranbp2) has a previously unanticipated role in Y-complex oligomerization. Our findings blur the established boundaries between scaffold and transport-channel Nups. We conclude that, similar to coated vesicles, several copies of the same structural building block--although compositionally identical--engage in different local sets of interactions and conformations.
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dimerization and direct membrane interaction of nup53 contribute to Nuclear Pore complex assembly
The EMBO Journal, 2012Co-Authors: Benjamin Vollmer, Allana Schooley, Ruchika Sachdev, Nathalie Eisenhardt, Anna Milena Schneider, Cornelia Sieverding, Johannes Madlung, Uwe Gerken, Boris Macek, Wolfram AntoninAbstract:Nuclear Pore complexes (NPCs) fuse the two membranes of the Nuclear envelope (NE) to a Pore, connecting cytoplasm and nucleoplasm and allowing exchange of macromolecules between these compartments. Most NPC proteins do not contain integral membrane domains and thus it is largely unclear how NPCs are embedded and anchored in the NE. Here, we show that the evolutionary conserved Nuclear Pore protein Nup53 binds independently of other proteins to membranes, a property that is crucial for NPC assembly and conserved between yeast and vertebrates. The vertebrate protein comprises two membrane binding sites, of which the C-terminal domain has membrane deforming capabilities, and is specifically required for de novo NPC assembly and insertion into the intact NE during interphase. Dimerization of Nup53 contributes to its membrane interaction and is crucial for its function in NPC assembly.
Ueli Aebi - One of the best experts on this subject based on the ideXlab platform.
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Towards reconciling structure and function in the Nuclear Pore complex
Histochemistry and Cell Biology, 2008Co-Authors: Ueli Aebi, Birthe FahrenkrogAbstract:The spatial separation between the cytoplasm and the cell nucleus necessitates the continuous exchange of macromolecular cargo across the double-membraned Nuclear envelope. Being the only passageway in and out of the nucleus, the Nuclear Pore complex (NPC) has the principal function of regulating the high throughput of nucleocytoplasmic transport in a highly selective manner so as to maintain cellular order and function. Here, we present a retrospective review of the evidence that has led to the current understanding of both NPC structure and function. Looking towards the future, we contemplate on how various outstanding effects and nanoscopic characteristics ought to be addressed, with the goal of reconciling structure and function into a single unified picture of the NPC.
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nanomechanical basis of selective gating by the Nuclear Pore complex
Science, 2007Co-Authors: Roderick Y. H. Lim, Joachim Köser, Birthe Fahrenkrog, Kyrill Schwarzherion, Jie Deng, Ueli AebiAbstract:The Nuclear Pore complex regulates cargo transport between the cytoplasm and the nucleus. We set out to correlate the governing biochemical interactions to the nanoscopic responses of the phenylalanineglycine (FG)-rich nucleoporin domains, which are involved in attenuating or promoting cargo translocation. We found that binding interactions with the transport receptor karyopherin-beta1 caused the FG domains of the human nucleoporin Nup153 to collapse into compact molecular conformations. This effect was reversed by the action of Ran guanosine triphosphate, which returned the FG domains into a polymer brush-like, entropic barrier conformation. Similar effects were observed in Xenopus oocyte nuclei in situ. Thus, the reversible collapse of the FG domains may play an important role in regulating nucleocytoplasmic transport.
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The Nuclear Pore complex: nucleocytoplasmic transport and beyond.
Nature Reviews Molecular Cell Biology, 2003Co-Authors: Birthe Fahrenkrog, Ueli AebiAbstract:Over the past two years, it has become evident that there is an unexpected link between Nuclear Pore complex structure and dynamics, nucleocytoplasmic transport and chromosome segregation. In addition, a tomographic three-dimensional reconstruction of native Nuclear Pore complexes preserved in thick amorphous ice has unveiled a number of new structural features of this supramolecular machine. These data, together with some of the elementary physical principles that underlie nucleocytoplasmic transport, will be discussed in this review.
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the Nuclear Pore complex from molecular architecture to functional dynamics
Current Opinion in Cell Biology, 1999Co-Authors: Daniel Stoffler, Birthe Fahrenkrog, Ueli AebiAbstract:Toward dissecting the molecular composition and architecture of the Nuclear Pore complex (NPC), over the past 18 months novel nucleoporins and NPC subcomplexes were identified and characterized. The three-dimensional structure of isolated yeast NPCs was determined by electron cryomicroscopy. New specimen preparation and labeling protocols localized a number of nucleoporins and NPC subcomplexes within the three-dimensional architecture of the yeast NPC. Structural changes of native NPCs mediated by physiological effectors such as calcium or ATP were monitored by time-lapse atomic force microscopy, thus revealing a first glimpse of the NPC's functional dynamics.
