Nuclear Import and Export: Transport Factors, Mechanisms and Regulation

1999 ◽  
Vol 9 (2) ◽  
pp. 89-106 ◽  
Author(s):  
Junona Moroianu
Keyword(s):  
Nuclear Import ◽  
Import And Export ◽  
Transport Factors

scholarly journals Nuclear Import of TFIIB Is Mediated by Kap114p, a Karyopherin with Multiple Cargo-binding Domains

2005 ◽  
Vol 16 (7) ◽  
pp. 3200-3210 ◽  
Author(s):  
Jennifer L. Hodges ◽  
Jennifer H. Leslie ◽  
Nima Mosammaparast ◽  
Yurong Guo ◽  
Jeffrey Shabanowitz ◽  
...  
Keyword(s):  
Nuclear Import ◽  
Binding Sites ◽  
Binding Domains ◽  
Transcription Factor Iib ◽  
General Transcription Factor ◽  
Proteomic Approach ◽  
Evolutionarily Conserved ◽  
Import And Export ◽  
Transport Factors

Nuclear import and export is mediated by an evolutionarily conserved family of soluble transport factors, the karyopherins (referred to as importins and exportins). The yeast karyopherin Kap114p has previously been shown to import histones H2A and H2B, Nap1p, and a component of the preinitiation complex (PIC), TBP. Using a proteomic approach, we have identified several potentially new cargoes for Kap114p. These cargoes include another PIC component, the general transcription factor IIB or Sua7p, which interacted directly with Kap114p. Consistent with its role as a Sua7p import factor, deletion of KAP114 led to specific mislocalization of Sua7p to the cytoplasm. An interaction between Sua7p and TBP was also detected in cytosol, raising the possibility that both Sua7p and TBP can be coimported by Kap114p. We have also shown that Kap114p possesses multiple overlapping binding sites for its partners, Sua7p, Nap1p, and H2A and H2B, as well as RanGTP and nucleoporins. In addition, we have assembled an in vitro complex containing Sua7p, Nap1p, and histones H2A and H2B, suggesting that this Kap may import several proteins simultaneously. The import of more than one cargo at a time would increase the efficiency of each import cycle and may allow the regulation of coimported cargoes.

scholarly journals Nuclear Import and Export Signals Control the Subcellular Localization of Nurr1 Protein in Response to Oxidative Stress

2013 ◽  
Vol 288 (8) ◽  
pp. 5506-5517 ◽  
Author(s):  
Ángel Juan García-Yagüe ◽  
Patricia Rada ◽  
Ana I. Rojo ◽  
Isabel Lastres-Becker ◽  
Antonio Cuadrado
Keyword(s):  
Oxidative Stress ◽  
Subcellular Localization ◽  
Nuclear Import ◽  
Import And Export

scholarly journals Armadillo nuclear import is regulated by cytoplasmic anchor Axin and nuclear anchor dTCF/Pan

Development ◽  
2001 ◽  
Vol 128 (11) ◽  
pp. 2107-2117 ◽  
Author(s):  
Nicholas S. Tolwinski ◽  
Eric Wieschaus
Keyword(s):  
Drosophila Melanogaster ◽  
Plasma Membrane ◽  
Nuclear Import ◽  
Current Model ◽  
Cellular Distribution ◽  
Nuclear Retention ◽  
Binding Partners ◽  
Wingless Signaling ◽  
Anchoring System ◽  
Import And Export

Drosophila melanogaster Armadillo plays two distinct roles during development. It is a component of adherens junctions, and functions as a transcriptional activator in response to Wingless signaling. In the current model, Wingless signal causes stabilization of cytoplasmic Armadillo allowing it to enter the nucleus where it can activate transcription. However, the mechanism of nuclear import and export remains to be elucidated. In this study, we show that two gain-of-function alleles of Armadillo activate Wingless signaling by different mechanisms. The S10 allele was previously found to localize to the nucleus, where it activates transcription. In contrast, the ΔArm allele localizes to the plasma membrane, and forces endogenous Arm into the nucleus. Therefore, ΔArm is dependent on the presence of a functional endogenous allele of arm to activate transcription. We show that ΔArm may function by titrating Axin protein to the membrane, suggesting that it acts as a cytoplasmic anchor keeping Arm out of the nucleus. In axin mutants, Arm is localized to the nuclei. We find that nuclear retention is dependent on dTCF/Pangolin. This suggests that cellular distribution of Arm is controlled by an anchoring system, where various nuclear and cytoplasmic binding partners determine its localization.

scholarly journals O-GlcNAc modification of nuclear pore complexes accelerates bi-directional transport

2020 ◽  
Author(s):  
Tae Yeon Yoo ◽  
Timothy J Mitchison
Keyword(s):  
Nuclear Import ◽  
Nuclear Transport ◽  
Super Resolution ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Pore ◽  
Permeability Barrier ◽  
Nuclear Pore Complexes ◽  
Facilitated Diffusion ◽  
Import And Export ◽  
Pore Complexes

AbstractMacromolecular transport across the nuclear envelope depends on facilitated diffusion through nuclear pore complexes (NPCs). The interior of NPCs contains a permeability barrier made of phenylalanine-glycine (FG) repeat domains that selectively facilitates the permeation of cargoes bound to nuclear transport receptors (NTRs). FG repeats in NPC are a major site of O-linked N-acetylglucosamine (O-GlcNAc) modification, but the functional role of this modification in nucleocytoplasmic transport is unclear. We developed high-throughput assays based on optogenetic probes to quantify the kinetics of nuclear import and export in living human cells. We found that increasing O-GlcNAc modification of the NPC accelerated NTR-facilitated nucleocytoplasmic transport of proteins in both directions, and decreasing modification slowed transport. Super-resolution imaging revealed strong enrichment of O-GlcNAc at the FG-repeat barrier. O-GlcNAc modification also accelerated passive permeation of a small, inert protein through NPCs. We conclude that O-GlcNAc modification accelerates nucleocytoplasmic transport by enhancing the non-specific permeability the FG-repeat barrier, perhaps by steric inhibition of interactions between FG repeats.SummaryNuclear pore complexes mediate nuclear transport and are highly modified with O-linked N-acetylglucosamine (O-GlcNAc) on FG repeat domains. Using a new quantitative live-cell imaging assay, Yoo and Mitchison demonstrate acceleration of nuclear import and export by O-GlcNAc modification.

Nuclear Import and Export of the Thyroid Hormone Receptor

2018 ◽  
pp. 45-66 ◽  
Author(s):  
Jibo Zhang ◽  
Vincent R. Roggero ◽  
Lizabeth A. Allison
Keyword(s):  
Thyroid Hormone ◽  
Nuclear Import ◽  
Hormone Receptor ◽  
Thyroid Hormone Receptor ◽  
Import And Export

Nuclear import and export of plant virus proteins and genomes

2006 ◽  
Vol 7 (2) ◽  
pp. 131-146 ◽  
Author(s):  
ALEXANDER KRICHEVSKY ◽  
STANISLAV V. KOZLOVSKY ◽  
YEDIDYA GAFNI ◽  
VITALY CITOVSKY
Keyword(s):  
Nuclear Import ◽  
Plant Virus ◽  
Import And Export ◽  
Virus Proteins

scholarly journals Nuclear Import and Export of Viruses and Virus Genomes

Virology ◽  
1998 ◽  
Vol 246 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Gary R. Whittaker ◽  
Ari Helenius
Keyword(s):  
Nuclear Import ◽  
Import And Export ◽  
Virus Genomes

Nuclear Import and Export in Plants and Animals

2005 ◽  
Author(s):  
Tzvi Tzfira ◽  
Vitaly Citovsky
Keyword(s):  
Nuclear Import ◽  
Import And Export

scholarly journals A Nuclear Import Pathway for a Protein Involved in tRNA Maturation

1997 ◽  
Vol 139 (7) ◽  
pp. 1655-1661 ◽  
Author(s):  
Jonathan S. Rosenblum ◽  
Lucy F. Pemberton ◽  
Günter Blobel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Import ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Sequence Similarity ◽  
Wild Type ◽  
Major Pathway ◽  
Trna Processing ◽  
Transport Factors ◽  
Limited Sequence

A limited number of transport factors, or karyopherins, ferry particular substrates between the cytoplasm and nucleoplasm. We identified the Saccharomyces cerevisiae gene YDR395w/SXM1 as a potential karyopherin on the basis of limited sequence similarity to known karyopherins. From yeast cytosol, we isolated Sxm1p in complex with several potential import substrates. These substrates included Lhp1p, the yeast homologue of the human autoantigen La that has recently been shown to facilitate maturation of pre-tRNA, and three distinct ribosomal proteins, Rpl16p, Rpl25p, and Rpl34p. Further, we demonstrate that Lhp1p is specifically imported by Sxm1p. In the absence of Sxm1p, Lhp1p was mislocalized to the cytoplasm. Sxm1p and Lhp1p represent the karyopherin and a cognate substrate of a unique nuclear import pathway, one that operates upstream of a major pathway of pre-tRNA maturation, which itself is upstream of tRNA export in wild-type cells. In addition, through its association with ribosomal proteins, Sxm1p may have a role in coordinating ribosome biogenesis with tRNA processing.

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