scholarly journals The Human Nuclear Pore Complex as Revealed by Cryo-Electron Tomography

Structure ◽  
2012 ◽  
Vol 20 (6) ◽  
pp. 998-1006 ◽  
Author(s):  
Tal Maimon ◽  
Nadav Elad ◽  
Idit Dahan ◽  
Ohad Medalia
Keyword(s):  
Nuclear Pore Complex ◽  
Electron Tomography ◽  
Nuclear Pore ◽  
Cryo Electron Tomography

scholarly journals Molecular architecture of the luminal ring of the Xenopus laevis nuclear pore complex

2020 ◽  
Author(s):  
Yanqing Zhang ◽  
Sai Li ◽  
Chao Zeng ◽  
Gaoxingyu Huang ◽  
Xuechen Zhu ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Nuclear Pore Complex ◽  
Electron Tomography ◽  
Structural Features ◽  
Rigid Base ◽  
Nuclear Pore ◽  
Molecular Architecture ◽  
Nuclear Membranes ◽  
Cryo Electron Microscopy ◽  
Cryo Electron Tomography

Nuclear pore complex (NPC) mediates the flow of substances between the nucleus and cytoplasm in eukaryotic cells. Here we report the cryo-electron tomography (cryo-ET) structure of the luminal ring (LR) of the NPC from Xenopus laevis oocyte. The observed key structural features of the LR are independently confirmed by single-particle cryo-electron microscopy (cryo-EM) analysis. The LR comprises eight butterfly-shaped subunits, each containing two symmetric wings. Each wing consists of four elongated, tubular protomers. Within the LR subunit, the eight protomers form a Finger domain, which directly contacts the fusion between the inner and outer nuclear membranes, and a Grid domain, which serves as a rigid base for the Finger domain. Two neighbouring LR subunits interact with each other through the lateral edges of their wings to constitute a Bumper domain, which displays two major conformations and appears to cushion neighbouring NPCs. Our study reveals previously unknown features of the LR and potentially explains the elastic property of the NPC.

scholarly journals The Structure of the Nuclear Pore Complex (An Update)

2019 ◽  
Vol 88 (1) ◽  
pp. 725-783 ◽  
Author(s):  
Daniel H. Lin ◽  
André Hoelz
Keyword(s):  
Nuclear Pore Complex ◽  
Electron Tomography ◽  
Structure And Function ◽  
Atomic Resolution ◽  
Nuclear Pore ◽  
Structural Studies ◽  
Protein Subunits ◽  
Cryo Electron Tomography ◽  
And Function

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.

scholarly journals Proteasomes tether to two distinct sites at the nuclear pore complex

2017 ◽  
Vol 114 (52) ◽  
pp. 13726-13731 ◽  
Author(s):  
Sahradha Albert ◽  
Miroslava Schaffer ◽  
Florian Beck ◽  
Shyamal Mosalaganti ◽  
Shoh Asano ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Binding Sites ◽  
Electron Tomography ◽  
Nuclear Pore ◽  
Cellular Environment ◽  
Subtomogram Averaging ◽  
Substrate Processing ◽  
Cellular Components ◽  
Transport Of Macromolecules

The partitioning of cellular components between the nucleus and cytoplasm is the defining feature of eukaryotic life. The nuclear pore complex (NPC) selectively gates the transport of macromolecules between these compartments, but it is unknown whether surveillance mechanisms exist to reinforce this function. By leveraging in situ cryo-electron tomography to image the native cellular environment of Chlamydomonas reinhardtii, we observed that nuclear 26S proteasomes crowd around NPCs. Through a combination of subtomogram averaging and nanometer-precision localization, we identified two classes of proteasomes tethered via their Rpn9 subunits to two specific NPC locations: binding sites on the NPC basket that reflect its eightfold symmetry and more abundant binding sites at the inner nuclear membrane that encircle the NPC. These basket-tethered and membrane-tethered proteasomes, which have similar substrate-processing state frequencies as proteasomes elsewhere in the cell, are ideally positioned to regulate transcription and perform quality control of both soluble and membrane proteins transiting the NPC.

Cryo-electron Tomography Provides Novel Insights into Nuclear Pore Architecture: Implications for Nucleocytoplasmic Transport

2003 ◽  
Vol 328 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Daniel Stoffler ◽  
Bernhard Feja ◽  
Birthe Fahrenkrog ◽  
Jochen Walz ◽  
Dieter Typke ◽  
...  
Keyword(s):  
Electron Tomography ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Pore ◽  
Pore Architecture ◽  
Cryo Electron Tomography

scholarly journals The path of pre-ribosomes through the nuclear pore complex revealed by electron tomography

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Franck Delavoie ◽  
Vanessa Soldan ◽  
Dana Rinaldi ◽  
Jean-Yves Dauxois ◽  
Pierre-Emmanuel Gleizes
Keyword(s):  
Nuclear Pore Complex ◽  
Electron Tomography ◽  
Nuclear Pore

scholarly journals Comprehensive Structure and Functional Adaptations of the Yeast Nuclear Pore Complex

2021 ◽  
Author(s):  
Christopher Akey ◽  
Digvijay Singh ◽  
Christina Ouch ◽  
Ignacia Echeverria ◽  
Ilona Nudelman ◽  
...  
Keyword(s):  
Electron Tomography ◽  
Nuclear Periphery ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Comprehensive Model ◽  
Cryo Electron Tomography ◽  
Pore Complexes ◽  
Transport Of Macromolecules

Nuclear Pore Complexes (NPCs) mediate the nucleocytoplasmic transport of macromolecules. Here we provide a structure of the yeast NPC in which the inner ring is resolved by cryo-EM at ɑ-helical resolution to show how flexible connectors tie together different structural and functional layers in the spoke. These connectors are targets for phosphorylation and regulated disassembly in cells with an open mitosis. Moreover, some nucleoporin pairs and karyopherins have similar interaction motifs, which suggests an evolutionary and mechanistic link between assembly and transport. We also provide evidence for three major NPC variants that foreshadow functional specializations at the nuclear periphery. Cryo-electron tomography extended these studies to provide a comprehensive model of the in situ NPC with a radially-expanded inner ring. Our model reveals novel features of the central transporter and nuclear basket, suggests a role for the lumenal ring in restricting dilation and highlights the structural plasticity required for transport by the NPC.

Snapshots of nuclear pore complexes in action captured by cryo-electron tomography

Nature ◽  
2007 ◽  
Vol 449 (7162) ◽  
pp. 611-615 ◽  
Author(s):  
Martin Beck ◽  
Vladan Lučić ◽  
Friedrich Förster ◽  
Wolfgang Baumeister ◽  
Ohad Medalia
Keyword(s):  
Electron Tomography ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Cryo Electron Tomography ◽  
Pore Complexes

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

Structure, assembly and interactions of the nuclear lamina and the nuclear pore complex

1992 ◽  
Vol 50 (1) ◽  
pp. 490-491
Author(s):  
N. Panté ◽  
M. Jarnik ◽  
E. Heitlinger ◽  
U. Aebi
Keyword(s):  
Nuclear Pore Complex ◽  
Divalent Cations ◽  
Nuclear Lamina ◽  
Dynamic Structure ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Pore ◽  
Cytoplasmic Filaments ◽  
Radial Spokes ◽  
Nuclear Ring ◽  
Central Plug

The nuclear pore complex (NPC) is a ∼120 MD supramolecular machine implicated in nucleocytoplasmic transport, that is embedded in the double-membraned nuclear envelope (NE). The basic framework of the ∼120 nm diameter NPC consists of a 32 MD cytoplasmic ring, a 66 MD ‘plug-spoke’ assembly, and a 21 MD nuclear ring. The ‘central plug’ seen in en face views of the NPC reveals a rather variable appearance indicating that it is a dynamic structure. Projecting from the cytoplasmic ring are 8 short, twisted filaments (Fig. 1a), whereas the nuclear ring is topped with a ‘fishtrap’ made of 8 thin filaments that join distally to form a fragile, 30-50 nm distal diameter ring centered above the NPC proper (Fig. 1b). While the cytoplasmic filaments are sensitive to proteases, they as well as the nuclear fishtraps are resistant to RNase treatment. Removal of divalent cations destabilizes the distal rings and thereby opens the fishtraps, addition causes them to reform. Protruding from the tips of the radial spokes into perinuclear space are ‘knobs’ that might represent the large lumenal domain of gp210, a membrane-spanning glycoprotein (Fig. 1c) which, in turn, may play a topogenic role in membrane folding and/or act as a membrane-anchoring site for the NPC. The lectin wheat germ agglutinin (WGA) which is known to recognize the ‘nucleoporins’, a family of glycoproteins having O-linked N-acetyl-glucosamine, is found in two locations on the NPC (Fig. 1. d-f): (i) whereas the cytoplasmic filaments appear unlabelled (Fig. 1d&e), WGA-gold labels sites between the central plug and the cytoplasmic ring (Fig. le; i.e., at a radius of 25-35 nm), and (ii) it decorates the distal ring of the nuclear fishtraps (Fig. 1, d&f; arrowheads).

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