Getting across the nuclear pore complex: new insights into nucleocytoplasmic transportThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 499-507 ◽  
Author(s):  
Daniel Stoffler ◽  
Kyrill Schwarz-Herion ◽  
Ueli Aebi ◽  
Birthe Fahrenkrog

Small ions and molecules can traverse the nuclear pore complex (NPC) simply by diffusion, whereas larger proteins and RNAs require specific signals and factors that facilitate their passage through the NPC. Our understanding of the factors that participate and regulate nucleocytoplasmic transport has increased tremendously over the past years, whereas the actual translocation step through the NPC has remained largely unclear. Here, we present and discuss recent findings on the interaction between the NPC and transport receptors and provide new evidence that the NPC acts as a constrained diffusion pore for molecules and particles without retention signal and as an affinity gate for signal-bearing cargos.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 279-286 ◽  
Author(s):  
Birthe Fahrenkrog

The nuclear pore complex (NPC) is the sole gateway between the nucleus and the cytoplasm of interphase eukaryotic cells, and it mediates all trafficking between these 2 cellular compartments. As such, the NPC and nuclear transport play central roles in translocating death signals from the cell membrane to the nucleus where they initiate biochemical and morphological changes occurring during apoptosis. Recent findings suggest that the correlation between the NPC, nuclear transport, and apoptosis goes beyond the simple fact that NPCs mediate nuclear transport of key players involved in the cell death program. In this context, the accessibility of key regulators of apoptosis appears to be highly modulated by nuclear transport (e.g., impaired nuclear import might be an apoptotic trigger). In this review, recent findings concerning the unexpected tight link between NPCs, nuclear transport, and apoptosis will be presented and critically discussed.


2021 ◽  
Vol 134 (2) ◽  
pp. jcs247874
Author(s):  
Giulia Paci ◽  
Joana Caria ◽  
Edward A. Lemke

ABSTRACTBidirectional transport of macromolecules across the nuclear envelope is a hallmark of eukaryotic cells, in which the genetic material is compartmentalized inside the nucleus. The nuclear pore complex (NPC) is the major gateway to the nucleus and it regulates nucleocytoplasmic transport, which is key to processes including transcriptional regulation and cell cycle control. Accordingly, components of the nuclear transport machinery are often found to be dysregulated or hijacked in diseases. In this Cell Science at a Glance article and accompanying poster, we provide an overview of our current understanding of cargo transport through the NPC, from the basic transport signals and machinery to more emerging aspects, all from a ‘cargo perspective’. Among these, we discuss the transport of large cargoes (>15 nm), as well as the roles of different cargo properties to nuclear transport, from size and number of bound nuclear transport receptors (NTRs), to surface and mechanical properties.


Author(s):  
N. Panté ◽  
M. Jarnik ◽  
E. Heitlinger ◽  
U. Aebi

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).


2009 ◽  
Vol 185 (3) ◽  
pp. 475-491 ◽  
Author(s):  
Evgeny Onischenko ◽  
Leslie H. Stanton ◽  
Alexis S. Madrid ◽  
Thomas Kieselbach ◽  
Karsten Weis

The nuclear pore complex (NPC) mediates all nucleocytoplasmic transport, yet its structure and biogenesis remain poorly understood. In this study, we have functionally characterized interaction partners of the yeast transmembrane nucleoporin Ndc1. Ndc1 forms a distinct complex with the transmembrane proteins Pom152 and Pom34 and two alternative complexes with the soluble nucleoporins Nup53 and Nup59, which in turn bind to Nup170 and Nup157. The transmembrane and soluble Ndc1-binding partners have redundant functions at the NPC, and disruption of both groups of interactions causes defects in Ndc1 targeting and in NPC structure accompanied by significant pore dilation. Using photoconvertible fluorescent protein fusions, we further show that the depletion of Pom34 in cells that lack NUP53 and NUP59 blocks new NPC assembly and leads to the reversible accumulation of newly made nucleoporins in cytoplasmic foci. Therefore, Ndc1 together with its interaction partners are collectively essential for the biosynthesis and structural integrity of yeast NPCs.


1987 ◽  
Vol 104 (5) ◽  
pp. 1143-1156 ◽  
Author(s):  
C M Snow ◽  
A Senior ◽  
L Gerace

Using monoclonal antibodies we identified a group of eight polypeptides of rat liver nuclear envelopes that have common epitopes. Most or all of these proteins are structurally distinct, as shown by tryptic peptide mapping and analysis with polyclonal antibodies. While these polypeptides are relatively tightly bound to nuclear membranes, only one is an integral membrane protein. The eight antigens cofractionate with the nuclear pore complex under various conditions of ionic strength and detergent. It can be seen by immunofluorescence microscopy that the monoclonal antibodies reacting with these antigens stain the nuclear surface of interphase cells in a finely punctate pattern. When the nuclear envelope is disassembled and subsequently reformed during mitosis, the proteins are reversibly dispersed throughout the cytoplasm in the form of minute foci. By EM immunogold localization on isolated nuclear envelopes, the monoclonal antibodies label exclusively the nuclear pore complex, at both its nucleoplasmic and cytoplasmic margins. Considered together, our biochemical and localization data indicate that the eight nuclear envelope polypeptides are pore complex components. As shown in the accompanying paper (Holt, G. D., C. M. Snow, A. Senior, R. S. Haltiwanger, L. Gerace, and G. W. Hart, J. Cell Biol., 104:1157-1164) these eight polypeptides contain a novel form of glycosylation, O-linked N-acetylglucosamine. The relative abundance and disposition of these O-linked glycoproteins in the pore complex are consistent with their having a role in nucleocytoplasmic transport.


1986 ◽  
Vol 102 (3) ◽  
pp. 859-862 ◽  
Author(s):  
M Schindler ◽  
L W Jiang

Fluorescence redistribution after photobleaching (FRAP) was used to examine the role of actin and myosin in the transport of dextrans through the nuclear pore complex. Anti-actin antibodies added to isolated rat liver nuclei significantly reduced the flux rate of fluorescently labeled 64-kD dextrans. The addition of 3 mM ATP to nuclei, which enhances the flux rate in control nuclei by approximately 250%, had no enhancement effect in the presence of either anti-actin or anti-myosin antibody. Phalloidin (10 microM) and cytochalasin D (1 micrograms/ml) individually inhibited the ATP stimulation of transport. Rabbit serum, anti-fibronectin, and anti-lamins A and C antibodies had no effect on transport. These results suggest a model for nuclear transport in which actin/myosin are involved in an ATP-dependent process that alters the effective transport rate across the nuclear pore complex.


1980 ◽  
Vol 192 (2) ◽  
pp. 753-759 ◽  
Author(s):  
R F Kletzien

The addition of 3′-deoxyadenosine (cordycepin) to cells in culture results in the inhibition of the appearance of mRNA in the cytoplasm through a mechanism thought to involve the inhibition of polyadenylate synthesis. I studied the effect of 3′-deoxyadenosine triphosphate, the physiologically active form of 3′-deoxyadenosine, on RNA release from isolated nuclei. Nuclei were isolated from baby-hamster kidney (BHK) fibroblasts that had been given a short pulse of radioactive uridine or adenosine in the presence of a low concentration of actinomycin D before harvest. RNA release from the isolated nuclei under the appropriate incubation conditions was time-, temperature- and ATP-dependent. 3′-Deoxyadenosine triphosphate inhibited RNA release from the isolated nuclei. However, RNA that was restricted to the nuclei during incubation with the drug could be chased out of the nuclei if the incubation medium was replaced with medium containing only ATP. The chased poly(A)+ (polyadenylated) RNA had shortened poly(A) tracts, indicating that poly(A)+ RNA with shortened poly(A) tracts can be transported out of the nucleus. An experiment was designed to test the effect of 3′-deoxyadenosine triphosphate on the release of poly(A)+ RNA at drug concentrations which caused 33 or 64% inhibition of RNA release. The release of poly(A)+ RNA and poly(A)- RNA (not polyadenylated) was equally inhibited by the drug. Thus, although 3′-deoxyadenosine triphosphate does inhibit release of RNA from the nucleus, it would appear that the drug does so through a mechanism independent of the inhibition of polyadenylation. The process that is inhibited must be one that is common to both poly(A)+ and poly(A)- RNA. The possibility that 3′-deoxyadenosine triphosphate inhibits a reaction at the nuclear membrane or nuclear pore complex is considered.


2010 ◽  
Vol 38 (1) ◽  
pp. 273-277 ◽  
Author(s):  
Jindriska Fiserova ◽  
Martin W. Goldberg

Eukaryotic cells have developed a series of highly controlled processes of transport between the nucleus and cytoplasm. The present review focuses on the latest advances in our understanding of nucleocytoplasmic exchange of molecules in yeast, a widely studied model organism in the field. It concentrates on the role of individual proteins such as nucleoporins and karyopherins in the translocation process and relates this to how the organization of the nuclear pore complex effectively facilitates the bidirectional transport between the two compartments.


Sign in / Sign up

Export Citation Format

Share Document