Nuclear Pore Complex Function in Saccharomyces cerevisiae Is Influenced by Glycosylation of the Transmembrane Nucleoporin Pom152p

The NUP1 gene of Saccharomyces cerevisiae encodes one member of a family of nuclear pore complex proteins (nucleoporins) conserved from yeast to vertebrates. We have used mutational analysis to investigate the function of Nup1p. Deletion of either the amino- or carboxy-terminal domain confers a lethal phenotype, but partial truncations at either end affect growth to varying extents. Amino-terminal truncation causes mislocalization and degradation of the mutant protein, suggesting that this domain is required for targeting Nup1p to the nuclear pore complex. Carboxy-terminal mutants are stable but do not have wild-type function, and confer a temperature sensitive phenotype. Both import of nuclear proteins and export of poly(A) RNA are defective at the nonpermissive temperature. In addition, nup1 mutant cells become multinucleate at all temperatures, a phenotype suggestive of a defect in nuclear migration. Tubulin staining revealed that the mitotic spindle appears to be oriented randomly with respect to the bud, in spite of the presence of apparently normal cytoplasmic microtubules connecting one spindle pole body to the bud tip. EM analysis showed that the nuclear envelope forms long projections extending into the cytoplasm, which appear to have detached from the bulk of the nucleus. Our results suggest that Nup1p may be required to retain the structural integrity between the nuclear envelope and an underlying nuclear scaffold, and that this connection is required to allow reorientation of the nucleus in response to cytoskeletal forces.

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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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The Nuclear Pore Complex Function of Sec13 Protein Is Required for Cell Survival during Retinal Development

Journal of Biological Chemistry ◽

10.1074/jbc.m114.547190 ◽

2014 ◽

Vol 289 (17) ◽

pp. 11971-11985 ◽

Cited By ~ 23

Author(s):

Xubo Niu ◽

Jian Hong ◽

Xiaofeng Zheng ◽

David B. Melville ◽

Ela W. Knapik ◽

...

Keyword(s):

Cell Survival ◽

Nuclear Pore Complex ◽

Retinal Development ◽

Complex Function ◽

Nuclear Pore

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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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Control of Genetic Parasites Mediated Through Nucleoporin Evolution

10.1101/215913 ◽

2017 ◽

Author(s):

Paul A. Rowley ◽

Kurt Patterson ◽

Suzanne B. Sandmeyer ◽

Sara L. Sawyer

Keyword(s):

Nuclear Pore Complex ◽

Protein Sequence ◽

Complex Function ◽

Nuclear Pore ◽

Evolutionary Trajectory ◽

Natural Sequence ◽

Genes Encoding ◽

Selection For ◽

Yeast Genes

AbstractYeasts serve as long-term hosts to several types of genetic parasites. Few studies have addressed the evolutionary trajectory of yeast genes that control the stable co-existence of these parasites with their host cell. In Saccharomyces yeasts, the retrovirus-like Ty retrotransposons must access the nucleus. We show that several genes encoding components of the yeast nuclear pore complex have experienced natural selection for substitutions that change the encoded protein sequence. By replacing these S. cerevisiae genes with orthologs from other Saccharomyces species, we discovered that natural sequence changes have affected the control of Ty retrotransposons. Specifically, changing the genetic sequence of NUP84 or NUP82 to what is found in other Saccharomyces species alters the retrotransposition of S. cerevisiae Ty1 and Ty3, respectively. Importantly, all tested housekeeping functions of NUP84 and NUP82 remained equivalent across species. The nuclear pore complex is the gatekeeper of the nucleus. It appears that nucleoporins are adapting to modulate the control of genetic parasites which access the nucleus, which is achieved despite the strict constraints imposed by host nuclear pore complex function.

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Faculty Opinions recommendation of Isolation and characterization of new Saccharomyces cerevisiae mutants perturbed in nuclear pore complex assembly.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1009805.135609 ◽

2002 ◽

Author(s):

Pamela Silver

Keyword(s):

Saccharomyces Cerevisiae ◽

Nuclear Pore Complex ◽

Nuclear Pore ◽

Complex Assembly ◽

Isolation And Characterization

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Quantitative Topographical Analysis of Nuclear Pore Complex Function Using Scanning Force Microscopy

Biophysical Journal ◽

10.1016/s0006-3495(03)74821-8 ◽

2003 ◽

Vol 85 (6) ◽

pp. 4093-4098 ◽

Cited By ~ 10

Author(s):

Rainer D. Jäggi ◽

Alfredo Franco-Obregón ◽

Klaus Ensslin

Keyword(s):

Nuclear Pore Complex ◽

Complex Function ◽

Scanning Force Microscopy ◽

Nuclear Pore ◽

Force Microscopy ◽

Scanning Force ◽

Topographical Analysis

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The FG-repeat asymmetry of the nuclear pore complex is dispensable for bulk nucleocytoplasmic transport in vivo

The Journal of Cell Biology ◽

10.1083/jcb.200407156 ◽

2004 ◽

Vol 167 (4) ◽

pp. 583-590 ◽

Cited By ~ 56

Author(s):

Bryan Zeitler ◽

Karsten Weis

Keyword(s):

Saccharomyces Cerevisiae ◽

Nuclear Pore Complex ◽

Nucleocytoplasmic Transport ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Nucleocytoplasmic Trafficking ◽

Transport Pathways ◽

Pore Complexes ◽

Biased Distribution

Nucleocytoplasmic transport occurs through gigantic proteinaceous channels called nuclear pore complexes (NPCs). Translocation through the NPC is exquisitely selective and is mediated by interactions between soluble transport carriers and insoluble NPC proteins that contain phenylalanine-glycine (FG) repeats. Although most FG nucleoporins (Nups) are organized symmetrically about the planar axis of the nuclear envelope, very few localize exclusively to one side of the NPC. We constructed Saccharomyces cerevisiae mutants with asymmetric FG repeats either deleted or swapped to generate NPCs with inverted FG asymmetry. The mutant Nups localize properly within the NPC and exhibit exchanged binding specificity for the export factor Xpo1. Surprisingly, we were unable to detect any defects in the Kap95, Kap121, Xpo1, or mRNA transport pathways in cells expressing the mutant FG Nups. These findings suggest that the biased distribution of FG repeats is not required for major nucleocytoplasmic trafficking events across the NPC.

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