Nuclear transport of baculovirus: Revealing the nuclear pore complex passage

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.

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Model Inspired by Nuclear Pore Complex Suggests Possible Roles for Nuclear Transport Receptors in Determining Its Structure

Biophysical Journal ◽

10.1016/j.bpj.2013.11.013 ◽

2013 ◽

Vol 105 (12) ◽

pp. 2781-2789 ◽

Cited By ~ 20

Author(s):

Dino Osmanović ◽

Ian J. Ford ◽

Bart W. Hoogenboom

Keyword(s):

Nuclear Pore Complex ◽

Nuclear Transport ◽

Nuclear Pore ◽

Transport Receptors

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GLE2, a Saccharomyces cerevisiae homologue of the Schizosaccharomyces pombe export factor RAE1, is required for nuclear pore complex structure and function.

Molecular Biology of the Cell ◽

10.1091/mbc.7.12.1921 ◽

1996 ◽

Vol 7 (12) ◽

pp. 1921-1937 ◽

Cited By ~ 119

Author(s):

R Murphy ◽

J L Watkins ◽

S R Wente

Keyword(s):

Saccharomyces Cerevisiae ◽

Schizosaccharomyces Pombe ◽

Nuclear Pore Complex ◽

Nuclear Export ◽

Protein Import ◽

Nuclear Transport ◽

Complex Structure ◽

Striking Similarity ◽

Nuclear Pore ◽

Pore Complexes

To identify and characterize novel factors required for nuclear transport, a genetic screen was conducted in the yeast Saccharomyces cerevisiae. Mutations that were lethal in combination with a null allele of the gene encoding the nucleoporin Nup100p were isolated using a colony-sectoring assay. Three complementation groups of gle (for GLFG lethal) mutants were identified. In this report, the characterization of GLE2 is detailed. GLE2 encodes a 40.5-kDa polypeptide with striking similarity to that of Schizosaccharomyces pombe RAE1. In indirect immunofluorescence and nuclear pore complex fractionation experiments, Gle2p was associated with nuclear pore complexes. Mutated alleles of GLE2 displayed blockage of polyadenylated RNA export; however, nuclear protein import was not apparently diminished. Immunofluorescence and thin-section electron microscopic analysis revealed that the nuclear pore complex and nuclear envelope structure was grossly perturbed in gle2 mutants. Because the clusters of herniated pore complexes appeared subsequent to the export block, the structural perturbations were likely indirect consequences of the export phenotype. Interestingly, a two-hybrid interaction was detected between Gle2p and Srp1p, the nuclear localization signal receptor, as well as Rip1p, a nuclear export signal-interacting protein. We propose that Gle2p has a novel role in mediating nuclear transport.

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Cargo Recognition Explains Nuclear Transport Regulation Induced by Nuclear Pore Complex Reorganization

Journal of Molecular Biology ◽

10.1016/j.jmb.2013.03.037 ◽

2013 ◽

Vol 425 (11) ◽

pp. 1849-1851 ◽

Cited By ~ 1

Author(s):

Naoko Imamoto

Keyword(s):

Nuclear Pore Complex ◽

Nuclear Transport ◽

Nuclear Pore ◽

Transport Regulation

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Nuclear envelope-vacuole contacts mitigate nuclear pore complex assembly stress

10.1101/2020.03.23.001719 ◽

2020 ◽

Cited By ~ 1

Author(s):

Christopher L. Lord ◽

Susan R. Wente

Keyword(s):

Saccharomyces Cerevisiae ◽

Nuclear Envelope ◽

Nuclear Pore Complex ◽

Lipid Droplets ◽

Budding Yeast ◽

Nuclear Transport ◽

Nuclear Pore ◽

Cellular Mechanisms ◽

Complex Assembly ◽

Cellular Effects

AbstractThe intricacy of nuclear pore complex (NPC) biogenesis imposes risks of failure that can cause defects in nuclear transport and nuclear envelope morphology, however, cellular mechanisms utilized to alleviate NPC assembly stress are not well-defined. In the budding yeast Saccharomyces cerevisiae, we demonstrate that NVJ1- and MDM1-enriched nuclear envelope (NE)-vacuole contacts increase when NPC assembly is compromised in several nup mutants, including nup116ΔGLFG cells. These interorganelle nucleus-vacuole junctions (NVJs) cooperate with lipid droplets to maintain viability and enhance NPC formation in assembly mutants. Additionally, NVJs function with ATG1 to promote vacuole-dependent remodeling in nup116ΔGLFG cells, which also correlates with proper NPC formation. Importantly, NVJs significantly improve the physiology of NPC assembly mutants, despite having only negligible effects when NPC biogenesis is unperturbed. Collectively, these results define how NE-vacuole interorganelle contacts coordinate responses to mitigate deleterious cellular effects caused by disrupted NPC assembly.SummaryHow cells respond to deleterious effects imposed by disrupted nuclear pore complex (NPC) assembly are not well-defined. The authors demonstrate nuclear envelope-vacuole interactions expand in response to perturbed NPC assembly to promote viability, nuclear envelope remodeling, and proper NPC biogenesis.

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The Nuclear Pore Complex and Nuclear Transport

Encyclopedia of Life Sciences ◽

10.1002/9780470015902.a0026034 ◽

2015 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Fadia Zagairy ◽

Boris Fichtman ◽

Amnon Harel

Keyword(s):

Nuclear Pore Complex ◽

Nuclear Transport ◽

Nuclear Pore

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Importin β contains a COOH-terminal nucleoporin binding region important for nuclear transport

The Journal of Cell Biology ◽

10.1083/jcb.200303085 ◽

2003 ◽

Vol 162 (3) ◽

pp. 391-401 ◽

Cited By ~ 97

Author(s):

Janna Bednenko ◽

Gino Cingolani ◽

Larry Gerace

Keyword(s):

Nuclear Pore Complex ◽

Nuclear Import ◽

Binding Sites ◽

Nuclear Transport ◽

Terminal Region ◽

Nuclear Pore ◽

Binding Region ◽

Similar Extent ◽

Importin Α ◽

Import Receptor

Proteins containing a classical NLS are transported into the nucleus by the import receptor importin β, which binds to cargoes via the adaptor importin α. The import complex is translocated through the nuclear pore complex by interactions of importin β with a series of nucleoporins. Previous studies have defined a nucleoporin binding region in the NH2-terminal half of importin β. Here we report the identification of a second nucleoporin binding region in its COOH-terminal half. Although the affinity of the COOH-terminal region for nucleoporins is dramatically weaker than that of the NH2-terminal region, sets of mutations that perturb the nucleoporin binding of either region reduce the nuclear import activity of importin β to a similar extent (∼50%). An importin β mutant with a combination of mutations in the NH2- and COOH-terminal regions is completely inactive for nuclear import. Thus, importin β possesses two nucleoporin binding sites, both of which are important for its nuclear import function.

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Nuclear transport defects and nuclear envelope alterations are associated with mutation of the Saccharomyces cerevisiae NPL4 gene.

Molecular Biology of the Cell ◽

10.1091/mbc.7.11.1835 ◽

1996 ◽

Vol 7 (11) ◽

pp. 1835-1855 ◽

Cited By ~ 46

Author(s):

C DeHoratius ◽

P A Silver

Keyword(s):

Nuclear Envelope ◽

Nuclear Pore Complex ◽

Protein Import ◽

Nuclear Protein ◽

Nuclear Transport ◽

Nuclear Pore ◽

Temperature Sensitive ◽

Nonpermissive Temperature ◽

Temperature Sensitive Mutants ◽

Nuclear Protein Import

To identify components involved in nuclear protein import, we used a genetic selection to isolate mutants that mislocalized a nuclear-targeted protein. We identified temperature-sensitive mutants that accumulated several different nuclear proteins in the cytoplasm when shifted to the semipermissive temperature of 30 degrees C; these were termed npl (nuclear protein localization) mutants. We now present the properties of yeast strains bearing mutations in the NPL4 gene and report the cloning of the NPL4 gene and the characterization of the Np14 protein. The npl4-1 mutant was isolated by the previously described selection scheme. The second allele, npl4-2, was identified from an independently derived collection of temperature-sensitive mutants. The npl4-1 and npl4-2 strains accumulate nuclear-targeted proteins in the cytoplasm at the nonpermissive temperature consistent with a defect in nuclear protein import. Using an in vitro nuclear import assay, we show that nuclei prepared from temperature-shifted npl4 mutant cells are unable to import nuclear-targeted proteins, even in the presence of cytosol prepared from wild-type cells. In addition, npl4-2 cells accumulate poly(A)+ RNA in the nucleus at the nonpermissive temperature, consistent with a failure to export mRNA from the nucleus. The npl4-1 and npl4-2 cells also exhibit distinct, temperature-sensitive structural defects: npl4-1 cells project extra nuclear envelope into the cytoplasm, whereas npl4-2 cells from nuclear envelope herniations that appear to be filled with poly(A)+ RNA. The NPL4 gene encodes an essential M(r) 64,000 protein that is located at the nuclear periphery and localizes in a pattern similar to nuclear pore complex proteins. Taken together, these results indicate that this gene encodes a novel nuclear pore complex or nuclear pore complex-associated component required for nuclear membrane integrity and nuclear transport.

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Measuring and Interpreting Nuclear Transport in Neurodegenerative Disease—The Example of C9orf72 ALS

International Journal of Molecular Sciences ◽

10.3390/ijms22179217 ◽

2021 ◽

Vol 22 (17) ◽

pp. 9217

Author(s):

Marije F. W. Semmelink ◽

Anton Steen ◽

Liesbeth M. Veenhoff

Keyword(s):

Nuclear Pore Complex ◽

Nuclear Transport ◽

Nucleocytoplasmic Transport ◽

Current Data ◽

Positive Answer ◽

Future Research ◽

Nuclear Pore ◽

Specific Proteins ◽

Open Question ◽

Kinetics Of

Transport from and into the nucleus is essential to all eukaryotic life and occurs through the nuclear pore complex (NPC). There are a multitude of data supporting a role for nuclear transport in neurodegenerative diseases, but actual transport assays in disease models have provided diverse outcomes. In this review, we summarize how nuclear transport works, which transport assays are available, and what matters complicate the interpretation of their results. Taking a specific type of ALS caused by mutations in C9orf72 as an example, we illustrate these complications, and discuss how the current data do not firmly answer whether the kinetics of nucleocytoplasmic transport are altered. Answering this open question has far-reaching implications, because a positive answer would imply that widespread mislocalization of proteins occurs, far beyond the reported mislocalization of transport reporters, and specific proteins such as FUS, or TDP43, and thus presents a challenge for future research.

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