Assessing Regulated Nuclear Transport in Saccharomyces cerevisiae

2014 ◽  
pp. 311-330 ◽  
Author(s):  
Christopher Ptak ◽  
Richard W. Wozniak
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Transport

Mechanisms of Nuclear Transport in the cell: RNA exosome in Saccharomyces cerevisiae

Bionatura ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 1423-1426
Author(s):  
Bruna Rech ◽  
Fernando A. Gonzales-Zubiate
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Catalytic Activity ◽  
Rna Processing ◽  
Cellular Localization ◽  
Nuclear Transport ◽  
Single Units ◽  
Yeast Saccharomyces Cerevisiae ◽  
Rna Transcripts ◽  
Non Coding Rnas ◽  
Rna Exosome

Ribonucleases (RNases) functions in the cell include precise maturation of non- coding RNAs and degradation of specific RNA transcripts that are no longer necessary. RNAses are present in the cell as single units or assembled as multimeric complexes; one of these complexes is the RNA exosome, a highly conserved complex essential for RNA processing and degradation. In the yeast Saccharomyces cerevisiae, the RNA exosome comprises eleven subunits, two with catalytic activity: Rrp6 and Rrp44, where the Rrp6 subunit is exclusively nuclear. Despite the RNA exosome has been intensively investigated since its discovery in 1997, only a few studies were accomplished concerning its nuclear transport. This review describes recent research about cellular localization and transport of this essential complex.

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

1996 ◽  
Vol 7 (12) ◽  
pp. 1921-1937 ◽  
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.

scholarly journals Nuclear envelope-vacuole contacts mitigate nuclear pore complex assembly stress

2020 ◽  
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.

pH and alcohol induced structural transition in Ntf2 a nuclear transport factor of Saccharomyces cerevisiae

2020 ◽  
Vol 159 ◽  
pp. 79-86
Author(s):  
Mohd. Kashif ◽  
Akhilendra Pratap Bharati ◽  
Sumit Kumar Chaturvedi ◽  
Rizwan Hasan Khan ◽  
Abrar Ahmad ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Structural Transition ◽  
Nuclear Transport ◽  
Transport Factor

scholarly journals In vivo nuclear transport kinetics in Saccharomyces cerevisiae: a role for heat shock protein 70 during targeting and translocation.

1996 ◽  
Vol 135 (2) ◽  
pp. 329-339 ◽  
Author(s):  
N Shulga ◽  
P Roberts ◽  
Z Gu ◽  
L Spitz ◽  
M M Tabb ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Nuclear Pore Complex ◽  
Heat Shock Protein 70 ◽  
Nuclear Transport ◽  
T Antigen ◽  
Nuclear Pore ◽  
Wild Type

The transport of proteins into the nucleus is a receptor-mediated process that is likely to involve between 50-100 gene products, including many that comprise the nuclear pore complex. We have developed an assay in Saccharomyces cerevisiae for the nuclear transport of green fluorescent protein fused to the SV-40 large T antigen nuclear localization signal (NLS-GFP). This assay allows the measurement of relative NLS-GFP nuclear import rates in wild-type and mutant cells under various physiological conditions. Probably the best understood component of the nuclear transport apparatus is Srp1p, the NLS receptor, which binds NLS-cargo in the cytoplasm and accompanies it into the nucleus. When compared to SRP1+ cells, NLS-GFP import rates in temperature-sensitive srp1-31 cells were slower and showed a lower temperature optimum. The in vivo transport defect of the srp1-31 cells was correlated with the purified protein's thermal sensitivity, as assayed by in vitro NLS peptide binding. We show that the kinetics of NLS-directed nuclear transport in wild-type cells is stimulated by the elevated expression of SSA1, which encodes a cytoplasmic heat shock protein 70 (Hsp70). Elevated Hsp70 levels are sufficient to suppress the NLS-GFP import defects in srp1-31 and nup82-3 cells. NUP82 encodes a protein that functions within the nuclear pore complex subsequent to docking. These results provide genetic evidence that Hsp70 acts during both targeting and translocation phases of nuclear transport, possibly as a molecular chaperone to promote the formation and stability of the Srp1p-NLS-cargo complex.

scholarly journals The role of karyopherins in the regulated sumoylation of septins

2007 ◽  
Vol 177 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Taras Makhnevych ◽  
Christopher Ptak ◽  
C. Patrick Lusk ◽  
John D. Aitchison ◽  
Richard W. Wozniak
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Pore Complex ◽  
Nuclear Transport ◽  
E3 Ligase ◽  
Nuclear Pore ◽  
Yeast Saccharomyces Cerevisiae ◽  
Septin Ring ◽  
M Phase

In the yeast Saccharomyces cerevisiae, several components of the septin ring are sumoylated during anaphase and then abruptly desumoylated at cytokinesis. We show that septin sumoylation is controlled by the interactions of two enzymes of the sumoylation pathway, Siz1p and Ulp1p, with the nuclear transport machinery. The E3 ligase Siz1p is imported into the nucleus by the karyopherin Kap95p during interphase. In M phase, Siz1p is exported from the nucleus by the karyopherin Kap142p/Msn5p and subsequently targeted to the septin ring, where it participates in septin sumoylation. We also show that the accumulation of sumoylated septins during mitosis is dependent on the interactions of the SUMO isopeptidase Ulp1p with Kap121p and Kap95p–Kap60p and the nuclear pore complex (NPC). In addition to sequestering Ulp1 at the NPC, Kap121p is required for targeting Ulp1p to the septin ring during mitosis. We present a model in which Ulp1p is maintained at the NPC during interphase and transiently interacts with the septin ring during mitosis.

scholarly journals The nucleoporins Nup170p and Nup157p are essential for nuclear pore complex assembly

2009 ◽  
Vol 185 (3) ◽  
pp. 459-473 ◽  
Author(s):  
Tadashi Makio ◽  
Leslie H. Stanton ◽  
Cheng-Chao Lin ◽  
David S. Goldfarb ◽  
Karsten Weis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Essential Role ◽  
Nuclear Transport ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Complex Assembly ◽  
Cytoplasmic Face ◽  
Pore Complexes

We have established that two homologous nucleoporins, Nup170p and Nup157p, play an essential role in the formation of nuclear pore complexes (NPCs) in Saccharomyces cerevisiae. By regulating their synthesis, we showed that the loss of these nucleoporins triggers a decrease in NPCs caused by a halt in new NPC assembly. Preexisting NPCs are ultimately lost by dilution as cells grow, causing the inhibition of nuclear transport and the loss of viability. Significantly, the loss of Nup170p/Nup157p had distinct effects on the assembly of different architectural components of the NPC. Nucleoporins (nups) positioned on the cytoplasmic face of the NPC rapidly accumulated in cytoplasmic foci. These nup complexes could be recruited into new NPCs after reinitiation of Nup170p synthesis, and may represent a physiological intermediate. Loss of Nup170p/Nup157p also caused core and nucleoplasmically positioned nups to accumulate in NPC-like structures adjacent to the inner nuclear membrane, which suggests that these nucleoporins are required for formation of the pore membrane and the incorporation of cytoplasmic nups into forming NPCs.

Nuclear transport: never-ending cycles of signals and receptors

2000 ◽  
Vol 36 ◽  
pp. 89-103 ◽  
Author(s):  
Dianne M. Barry ◽  
Susan R. Wente
Keyword(s):  
Nuclear Transport
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