The BiP protein and the endoplasmic reticulum of Schizosaccharomyces pombe: fate of the nuclear envelope during cell division

1993 ◽  
Vol 105 (4) ◽  
pp. 1115-1120 ◽  
Author(s):  
A.L. Pidoux ◽  
J. Armstrong

A polyclonal antibody was raised to the C-terminal region of fission yeast BiP. The use of this antibody for immunoprecipitation, western blotting and immunofluorescence has confirmed and extended the observations made previously with an epitope-tagged BiP molecule. A fraction of BiP protein is glycosylated in Schizosaccharomyces pombe cells. Pulse-chase experiments showed that this modification occurs rapidly upon synthesis and that the extent of glycosylation does not then change with time. BiP protein is induced by elevated temperatures and by treatment with tunicamycin. The antibody cross-reacts with proteins of similar molecular weight in the yeasts Kluyveromyces lactis and Schizosaccharomyces japonicus. Immunofluorescence of BiP has been used to follow the behaviour of the ER and in particular the nuclear envelope through the cell cycle.

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yasunao Kamikawa ◽  
Atsushi Saito ◽  
Koji Matsuhisa ◽  
Masayuki Kaneko ◽  
Rie Asada ◽  
...  

AbstractThe nuclear envelope (NE) safeguards the genome and is pivotal for regulating genome activity as the structural scaffold of higher-order chromatin organization. NE had been thought as the stable during the interphase of cell cycle. However, recent studies have revealed that the NE can be damaged by various stresses such as mechanical stress and cellular senescence. These types of stresses are called NE stress. It has been proposed that NE stress is closely related to cellular dysfunctions such as genome instability and cell death. Here, we found that an endoplasmic reticulum (ER)-resident transmembrane transcription factor, OASIS, accumulates at damaged NE. Notably, the major components of nuclear lamina, Lamin proteins were depleted at the NE where OASIS accumulates. We previously demonstrated that OASIS is cleaved at the membrane domain in response to ER stress. In contrast, OASIS accumulates as the full-length form to damaged NE in response to NE stress. The accumulation to damaged NE is specific for OASIS among OASIS family members. Intriguingly, OASIS colocalizes with the components of linker of nucleoskeleton and cytoskeleton complexes, SUN2 and Nesprin-2 at the damaged NE. OASIS partially colocalizes with BAF, LEM domain proteins, and a component of ESCRT III, which are involved in the repair of ruptured NE. Furthermore, OASIS suppresses DNA damage induced by NE stress and restores nuclear deformation under NE stress conditions. Our findings reveal a novel NE stress response pathway mediated by OASIS.


2005 ◽  
Vol 277-279 ◽  
pp. 1-6 ◽  
Author(s):  
Young Joo Jang ◽  
Young Sook Kil ◽  
Jee Hee Ahn ◽  
Jae Hoon Ji ◽  
Jong Seok Lim ◽  
...  

The fission yeast, Schizosaccharomyces pombe is a single-celled free-living fungus that shares many features with cells of more complicated eukaryotes. Many of the genes required for the cell-cycle control, proteolysis, protein modification, and RNA splicing are highly conserved with those of higher eukaryotes. Moreover, fission yeast has the merit of genetics and its genetic system is already well characterized. As such, the current study evaluated the use of a fission yeast system as a tool for the functional study of mammalian genes and attempted to set up an assay system for novel genes. Since the phenotypes of a deletion mutant and the overexpression of a gene are generally analyzed for a functional study of specific genes in yeast, the present study used overexpression phenotypes to study the functions of mammalian genes. Therefore, based on using a thiamine-repressive promoter, two mammalian genes were expressed in fission yeast, and their overexpressed phenotypes compared with those in mammalian cells. The phenotypes resulting from overexpression were analyzed using a FACS, which analyzes the DNA contents, and a microscope. One of the selected genes was the mammalian Polo-like kinase 1 (Plk1), which is activated and plays a role in the mitotic phase of the cell division cycle. The overexpression of various constructs of Plk1 in the HeLa cells caused cell cycle defects, suggesting that the ectopic Plk1s blocked the endogenous Plk1 in the cells. As expected, when the constructs were overexpressed in the fission yeast system, the cells were arrested in mitosis and defected at the end of mitosis. As such, this data suggests that the Plk1-overexpressed phenotypes were similar in the mammalian cells and the fission yeast, thereby enabling the mammalian Plk1 functions to be approximated in the fission yeast. The other selected gene was the N-Myc downstream-regulated gene 2 (ndrg2), which is upregulated during cell differentiation, yet still not well characterized. When the ndrg2 gene was overexpressed in the fission yeast, the cells contained multi-septa. The septa were positioned well, yet their number increased per cell. Therefore, this gene was speculated to block cell division in the last stage of the cell cycle, making the phenotype potentially useful for explaining cell growth and differentiation in mammalian cells. Accordingly, fission yeast is demonstrated to be an appropriate species for the functional study of mammalian genes.


1978 ◽  
Vol 33 (1) ◽  
pp. 399-411
Author(s):  
J. Creanor

Oxygen uptake was measured in synchronous cultures of the fission yeast Schizosaccharomyces pombe. The rate of oxygen uptake was found to increase in a step-wise manner at the beginning of the cycle and again in the middle of the cycle. The increases in rate were such that overall, oxygen uptake doubled in rate once per cell cycle. Addition of inhibitors of DNA synthesis or nuclear division to a synchronous culture did not affect the uptake of oxygen. In an induced synchronous culture, in which DNA synthesis, cell division, and nuclear division, but not ‘growth’ were synchronized, oxygen uptake increased continuously in rate and did not show the step-wise rises which were shown in the selection-synchronized culture. These results were compared with previous measurements of oxygen uptake in yeast and an explanation is suggested for the many different patterns which have been reported.


Cells ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 687 ◽  
Author(s):  
Florentin Huguet ◽  
Shane Flynn ◽  
Paola Vagnarelli

The role of kinases in the regulation of cell cycle transitions is very well established, however, over the past decade, studies have identified the ever-growing importance of phosphatases in these processes. It is well-known that an intact or otherwise non-deformed nuclear envelope (NE) is essential for maintaining healthy cells and any deviation from this can result in pathological conditions. This review aims at assessing the current understanding of how phosphatases contribute to the remodelling of the nuclear envelope during its disassembling and reformation after cell division and how errors in this process may lead to the development of diseases.


2002 ◽  
Vol 22 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Cong-Jun Li ◽  
Melvin L. DePamphilis

ABSTRACT Previous studies have shown that changes in the affinity of the hamster Orc1 protein for chromatin during the M-to-G1 transition correlate with the activity of hamster origin recognition complexes (ORCs) and the appearance of prereplication complexes at specific sites. Here we show that Orc1 is selectively released from chromatin as cells enter S phase, converted into a mono- or diubiquitinated form, and then deubiquitinated and re-bound to chromatin during the M-to-G1 transition. Orc1 is degraded by the 26S proteasome only when released into the cytosol, and peptide additions to Orc1 make it hypersensitive to polyubiquitination. In contrast, Orc2 remains tightly bound to chromatin throughout the cell cycle and is not a substrate for ubiquitination. Since the concentration of Orc1 remains constant throughout the cell cycle, and its half-life in vivo is the same as that of Orc2, ubiquitination of non-chromatin-bound Orc1 presumably facilitates the inactivation of ORCs by sequestering Orc1 during S phase. Thus, in contrast to yeast (Saccharomyces cerevisiae and Schizosaccharomyces pombe), mammalian ORC activity appears to be regulated during each cell cycle through selective dissociation and reassociation of Orc1 from chromatin-bound ORCs.


BIOspektrum ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 739-742
Author(s):  
Anne Schlaitz

AbstractIn order to divide successfully, cells need to reorganize their interior including membrane-bound organelles such as the endoplasmic reticulum (ER). The ER serves as sink and source for the nuclear envelope and undergoes distinct transformations in its morphology and dynamics during cell division. To fully appreciate the functions of ER remodeling during cell division it will be essential to first achieve a detailed understanding of the underlying molecular mechanisms.


1987 ◽  
Vol 87 (2) ◽  
pp. 323-325
Author(s):  
B. Novak ◽  
J.M. Mitchison

CO2 production has been followed by manometry in synchronous and asynchronous control cultures of Schizosaccharomyces pombe prepared by elutriation from the same initial culture. Earlier results showed a periodic change in the rate of production, which took place once per cell cycle. These changes were most clearly shown as oscillations in the difference between values of the second differential (acceleration) for the synchronous and asynchronous cultures. This paper shows that the oscillations continue for at least three cycles in the presence of cycloheximide (with and without chloramphenicol). Protein synthesis is virtually absent and there is no cell division. The control of this metabolic oscillation is therefore not directly dependent on translation. The period of the oscillation under these conditions is about 60% of the normal cycle time.


1978 ◽  
Vol 76 (3) ◽  
pp. 692-704 ◽  
Author(s):  
T E Miller ◽  
C Y Huang ◽  
A O Pogo

Small molecular weight RNA species (smwRNAs) were studied in rat liver nuclei with and without chromatin as well as with and without nuclear envelope and nucleoplasm. From all the species identified, only two, N5 and 5Sb, were related to ribosomes. The others were localized exclusively in the nuclear skeleton or the spongelike network that was described in the preceding communication. This network or protein matrix contains a less abundant but exclusive set of molecules designated 5Sa, N1, and 4.5S, as well as other more abundant molecules which also exist in rat liver endoplasmic reticulum but not in polysomes or postribosomal RNP complexes. The smwRNAs behave like HnRNA; they remain located in the nuclear skeleton when nuclei are deprived of nucleoplasm and chromatin. With the information presently available, it is not possible to know whetherer both species are in the same or different RNP complexes and whether some of the smwRNAs contribute to the architecture of the nuclear skeleton. Distinct from any other nuclear RNA species, smwRNAs have two unique properties: facility of extraction, and resistance to nuclear ribonuclease digestion.


2019 ◽  
Author(s):  
Jesse T. Chao ◽  
Francisco Piña ◽  
Masayuki Onishi ◽  
Yifat Cohen ◽  
Maya Schuldiner ◽  
...  

SUMMARYDuring cell division, cells must actively pass on organelles. Previously, we discovered the endoplasmic reticulum (ER) stress surveillance (ERSU) pathway that ensures the inheritance of functional ER. Activation of the ERSU causes the septin ring to mislocalize, which blocks ER inheritance and cytokinesis. Here, we found that the septin ring mislocalizes to previously utilized cell division sites called cytokinetic remnants (CRMs). The transfer of the septin ring to CRMs requires Nba1, a negative polarity component that normally prevents septin ring formation at CRMs. Furthermore, septin ring movement to CRMs relies on the ERSU component Slt2, which is recruited by binding Bem1. During ER stress, Bem1 also binds the GTP exchange factor Cdc24, without activating Cdc42, a GTPase that normally establishes polarized growth. Failure to translocate septin rings to CRMs delays the cell’s ability to re-enter cell division when ER homeostasis is re-established. Thus, ER stress considers the history of previous cell cycle for future cell cycle re-entry upon ER stress recovery.


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