scholarly journals Yeast Nuclear Envelope Subdomains with Distinct Abilities to Resist Membrane Expansion

2006 ◽  
Vol 17 (4) ◽  
pp. 1768-1778 ◽  
Author(s):  
Joseph L. Campbell ◽  
Alexander Lorenz ◽  
Keren L. Witkin ◽  
Thomas Hays ◽  
Josef Loidl ◽  
...  

Little is known about what dictates the round shape of the yeast Saccharomyces cerevisiae nucleus. In spo7Δ mutants, the nucleus is misshapen, exhibiting a single protrusion. The Spo7 protein is part of a phosphatase complex that represses phospholipid biosynthesis. Here, we report that the nuclear protrusion of spo7Δ mutants colocalizes with the nucleolus, whereas the nuclear compartment containing the bulk of the DNA is unaffected. Using strains in which the nucleolus is not intimately associated with the nuclear envelope, we show that the single nuclear protrusion of spo7Δ mutants is not a result of nucleolar expansion, but rather a property of the nuclear membrane. We found that in spo7Δ mutants the peripheral endoplasmic reticulum (ER) membrane was also expanded. Because the nuclear membrane and the ER are contiguous, this finding indicates that in spo7Δ mutants all ER membranes, with the exception of the membrane surrounding the bulk of the DNA, undergo expansion. Our results suggest that the nuclear envelope has distinct domains that differ in their ability to resist membrane expansion in response to increased phospholipid biosynthesis. We further propose that in budding yeast there is a mechanism, or structure, that restricts nuclear membrane expansion around the bulk of the DNA.

2020 ◽  
Vol 219 (12) ◽  
Author(s):  
Christopher L. Lord ◽  
Susan R. Wente

The intricacy of nuclear pore complex (NPC) biogenesis imposes risks of failure that can cause defects in nuclear transport and nuclear envelope (NE) morphology; however, cellular mechanisms used to alleviate NPC assembly stress are not well defined. In the budding yeast Saccharomyces cerevisiae, we demonstrate that NVJ1- and MDM1-enriched 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 remodel the NE and promote vacuole-dependent degradation of specific nucleoporins in nup116ΔGLFG cells. Importantly, NVJs significantly improve the physiology of NPC assembly mutants, despite having only negligible effects when NPC biogenesis is unperturbed. These results therefore define how NE–vacuole interorganelle contacts coordinate responses to mitigate deleterious cellular effects caused by disrupted NPC assembly.


2003 ◽  
Vol 163 (6) ◽  
pp. 1255-1266 ◽  
Author(s):  
Paula Estrada ◽  
Jiwon Kim ◽  
Jeff Coleman ◽  
Lee Walker ◽  
Brian Dunn ◽  
...  

Myo4p is a nonessential type V myosin required for the bud tip localization of ASH1 and IST2 mRNA. These mRNAs associate with Myo4p via the She2p and She3p proteins. She3p is an adaptor protein that links Myo4p to its cargo. She2p binds to ASH1 and IST2 mRNA, while She3p binds to both She2p and Myo4p. Here we show that Myo4p and She3p, but not She2p, are required for the inheritance of cortical ER in the budding yeast Saccharomyces cerevisiae. Consistent with this observation, we find that cortical ER inheritance is independent of mRNA transport. Cortical ER is a dynamic network that forms cytoplasmic tubular connections to the nuclear envelope. ER tubules failed to grow when actin polymerization was blocked with the drug latrunculin A (Lat-A). Additionally, a reduction in the number of cytoplasmic ER tubules was observed in Lat-A–treated and myo4Δ cells. Our results suggest that Myo4p and She3p facilitate the growth and orientation of ER tubules.


Microbiology ◽  
1997 ◽  
Vol 143 (6) ◽  
pp. 1867-1876 ◽  
Author(s):  
P. A. Radcliffe ◽  
K. M. Binley ◽  
J. Trevethick ◽  
M. Hall ◽  
P. E. Sudbery

F1000Research ◽  
2018 ◽  
Vol 6 ◽  
pp. 1804 ◽  
Author(s):  
Peter Wild ◽  
Andres Kaech ◽  
Elisabeth M. Schraner ◽  
Ladina Walser ◽  
Mathias Ackermann

Background: Herpesvirus capsids are assembled in the nucleus, translocated to the perinuclear space by budding, acquiring tegument and envelope, or released to the cytoplasm via impaired nuclear envelope. One model proposes that envelopment, “de-envelopment” and “re-envelopment” is essential for production of infectious virus. Glycoproteins gB/gH were reported to be essential for de-envelopment, by fusion of the “primary” envelope with the outer nuclear membrane. Yet, a high proportion of enveloped virions generated from genomes with deleted gB/gH were found in the cytoplasm and extracellular space, suggesting the existence of alternative exit routes.Methods: We investigated the relatedness between the nuclear envelope and membranes of the endoplasmic reticulum and Golgi complex, in cells infected with either herpes simplex virus 1 (HSV-1) or a Us3 deletion mutant thereof, or with bovine herpesvirus 1 (BoHV-1) by transmission and scanning electron microscopy, employing freezing technique protocols.Results:  The Golgi complex is a compact entity in a juxtanuclear position covered by a membrane on thecisface. Golgi membranes merge with membranes of the endoplasmic reticulum forming an entity with the perinuclear space. All compartments contained enveloped virions. After treatment with brefeldin A, HSV-1 virions aggregated in the perinuclear space and endoplasmic reticulum, while infectious progeny virus was still produced.Conclusions: The data suggest that virions derived by budding at nuclear membranes are intraluminally transported from the perinuclear space via Golgi -endoplasmic reticulum transitions into Golgi cisternae for packaging. Virions derived by budding at nuclear membranes are infective like Us3 deletion mutants, which  accumulate in the perinuclear space. Therefore, i) de-envelopment followed by re-envelopment is not essential for production of infective progeny virus, ii) the process taking place at the outer nuclear membrane is budding not fusion, and iii) naked capsids gain access to the cytoplasmic matrix via impaired nuclear envelope as reported earlier.


2005 ◽  
Vol 16 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Annette L. Henneberry ◽  
Stephen L. Sturley

Metallomics ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1257-1263 ◽  
Author(s):  
Yasumitsu Ogra ◽  
Maya Shimizu ◽  
Kazuaki Takahashi ◽  
Yasumi Anan

Organic selenium metabolites of plants and animals such as selenoamino acids and selenosugars are metabolized to selenomethionine in yeast.


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