Yeast and vertebrate nuclear-pore complexes: evolutionary conserved, yet divergent macromolecular assemblies

Belgareh, Naïma; Doye, Valérie

doi:10.1007/bf01453442

Cited by 3 publications

(2 citation statements)

References 99 publications

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“…From a central spoke ring embedded in the nuclear membranes emanate eight cytoplasmic and nuclear filaments, the latter joined by a distal ring to form the nuclear basket. A wealth of biochemical and genetic data on the protein subunits (nucleoporins) of NPCs has become available recently (Belgareh and Doye, 1999;Ryan and Wente, 2000), producing a basically complete inventory of yeast (Rout et al, 2000) and a steadily growing list of vertebrate nucleoporins.…”

Section: Introductionmentioning

confidence: 99%

Nuclear pore complexes form immobile networks and have a very low turnover in live mammalian cells

Daigle

Beaudouin

Hartnell

et al. 2001

The Journal of Cell Biology

362

313

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The nuclear pore complex (NPC) and its relationship to the nuclear envelope (NE) was characterized in living cells using POM121–green fluorescent protein (GFP) and GFP-Nup153, and GFP–lamin B1. No independent movement of single pore complexes was found within the plane of the NE in interphase. Only large arrays of NPCs moved slowly and synchronously during global changes in nuclear shape, strongly suggesting mechanical connections which form an NPC network. The nuclear lamina exhibited identical movements. NPC turnover measured by fluorescence recovery after photobleaching of POM121 was less than once per cell cycle. Nup153 association with NPCs was dynamic and turnover of this nucleoporin was three orders of magnitude faster. Overexpression of both nucleoporins induced the formation of annulate lamellae (AL) in the endoplasmic reticulum (ER). Turnover of AL pore complexes was much higher than in the NE (once every 2.5 min). During mitosis, POM121 and Nup153 were completely dispersed and mobile in the ER (POM121) or cytosol (Nup153) in metaphase, and rapidly redistributed to an immobilized pool around chromatin in late anaphase. Assembly and immobilization of both nucleoporins occurred before detectable recruitment of lamin B1, which is thus unlikely to mediate initiation of NPC assembly at the end of mitosis.

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Section: Introductionmentioning

confidence: 99%

Nuclear pore complexes form immobile networks and have a very low turnover in live mammalian cells

Daigle

Beaudouin

Hartnell

et al. 2001

The Journal of Cell Biology

362

313

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“…Although the cytoplasmic filaments spread outward, the nuclear filaments conjoin distally to form a basket-like structure (8,9). This general architecture of NPCs is highly conserved between all eukaryotes, and many of the Nups are conserved across phyla (10). Genome analysis had revealed that half of the yeast nucleoporins contain phenylalanine-glycine (FG) repeats, either as FG, PSFG, FXFG, or GLFG repeats.…”

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confidence: 99%

Docking of HIV-1 Vpr to the Nuclear Envelope Is Mediated by the Interaction with the Nucleoporin hCG1

Rouzic¹,

Mousnier²,

Rustum³

et al. 2002

Journal of Biological Chemistry

103

109

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The HIV-1 genome contains several genes coding for auxiliary proteins, including the small Vpr protein. Vpr affects the integrity of the nuclear envelope and participates in the nuclear translocation of the preintegration complex containing the viral DNA. Here, we show by photobleaching experiments performed on living cells expressing a Vpr-green fluorescent protein fusion that the protein shuttles between the nucleus and the cytoplasm, but a significant fraction is concentrated at the nuclear envelope, supporting the hypothesis that Vpr interacts with components of the nuclear pore complex. An interaction between HIV-1 Vpr and the human nucleoporin CG1 (hCG1) was revealed in the yeast twohybrid system, and then confirmed both in vitro and in transfected cells. This interaction does not involve the FG repeat domain of hCG1 but rather the N-terminal region of the protein. Using a nuclear import assay based on digitonin-permeabilized cells, we demonstrate that hCG1 participates in the docking of Vpr at the nuclear envelope. This association of Vpr with a component of the nuclear pore complex may contribute to the disruption of the nuclear envelope and to the nuclear import of the viral DNA.In contrast to oncoretroviruses that replicate only in dividing cells and enter the nucleus upon nuclear breakdown during mitosis, HIV-1 1 and other lentiviruses have the ability to infect non-dividing cells, such as macrophages and quiescent T lymphocytes. After entry of the virus into the cell, the HIV capsid seems to uncoat rapidly. The genomic HIV-1 RNA is reverse transcribed into linear double-stranded DNA, which remains associated with a nucleoprotein complex, called the preintegration complex (PIC). The viral DNA is then imported into the nucleus through the nuclear envelope (NE) via an active mechanism within 4 -6 h after infection (1).In eukaryotic cells, the NE creates distinct nuclear and cytoplasmic compartments. This structure consists of two concentric membranes, the inner and outer nuclear membranes which are continuous with the endoplasmic reticulum. The NE is stabilized by the nuclear lamina, a tight meshwork of intermediate filament proteins underlying the inner nuclear membrane (for review, see Ref.2), whereas on the outer side, cytoplasmic intermediate filaments in close contact with the nucleus serve to suspend the nucleus in the cytoplasm (3). Spanning both membranes are nuclear pore complexes (NPC) that form aqueous channels, which allow selective traffic between nucleus and cytoplasm and impose a permeability barrier to free diffusion of macromolecules or complexes. The NPC is a large supramolecular structure (4) formed of ϳ30 unique proteins in vertebrates, termed nucleoporins (Nups) giving rise to an estimated molecular mass of 60 MDa (Ref. 5; for reviews, see Refs. 6 and 7). High resolution electron microscopic images of NPCs reveal an 8-fold symmetric structure, formed by nuclear and cytoplasmic rings and a central spoke complex. Peripheral filaments emanate from the core of the complex into the nucle...

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An evolutionarily conserved NPC subcomplex, which redistributes in part to kinetochores in mammalian cells

Belgareh

Rabut

Baï

et al. 2001

The Journal of Cell Biology

299

312

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The nuclear pore complexes (NPCs) are evolutionarily conserved assemblies that allow traffic between the cytoplasm and the nucleus. In this study, we have identified and characterized a novel human nuclear pore protein, hNup133, through its homology with the Saccharomyces cerevisiae nucleoporin scNup133. Two-hybrid screens and immunoprecipitation experiments revealed a direct and evolutionarily conserved interaction between Nup133 and Nup84/Nup107 and indicated that hNup133 and hNup107 are part of a NPC subcomplex that contains two other nucleoporins (the previously characterized hNup96 and a novel nucleoporin designated as hNup120) homologous to constituents of the scNup84 subcomplex. We further demonstrate that hNup133 and hNup107 are localized on both sides of the NPC to which they are stably associated at interphase, remain associated as part of a NPC subcomplex during mitosis, and are targeted at early stages to the reforming nuclear envelope. Throughout mitosis, a fraction of hNup133 and hNup107 localizes to the kinetochores, thus revealing an unexpected connection between structural NPCs constituents and kinetochores. Photobleaching experiments further showed that the mitotic cytoplasm contains kinetochore-binding competent hNup133 molecules and that in contrast to its stable association with the NPCs the interaction of this nucleoporin with kinetochores is dynamic.

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Yeast and vertebrate nuclear-pore complexes: evolutionary conserved, yet divergent macromolecular assemblies

Cited by 3 publications

References 99 publications

Nuclear pore complexes form immobile networks and have a very low turnover in live mammalian cells

Nuclear pore complexes form immobile networks and have a very low turnover in live mammalian cells

Docking of HIV-1 Vpr to the Nuclear Envelope Is Mediated by the Interaction with the Nucleoporin hCG1

An evolutionarily conserved NPC subcomplex, which redistributes in part to kinetochores in mammalian cells

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