scholarly journals A distinct inner nuclear membrane proteome in Saccharomyces cerevisiae gametes

2021 ◽  
Author(s):  
Shary N Shelton ◽  
Sarah E Smith ◽  
Jay R Unruh ◽  
Sue L Jaspersen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Membrane ◽  
De Novo ◽  
Protein Composition ◽  
Parental Cell ◽  
Permeability Barrier ◽  
Developmentally Regulated ◽  
Inner Nuclear Membrane ◽  
Expression Of Genes ◽  
Mitotic Cells

Abstract The inner nuclear membrane (INM) proteome regulates gene expression, chromatin organization, and nuclear transport; however, it is poorly understood how changes in INM protein composition contribute to developmentally regulated processes, such as gametogenesis. We conducted a screen to determine how the INM proteome differs between mitotic cells and gametes. In addition, we used a strategy that allowed us to determine if spores synthesize their INM proteins de novo, rather than inheriting their INM proteins from the parental cell. This screen used a split-GFP complementation system, where we were able to compare the distribution of all C-terminally tagged transmembrane proteins in Saccharomyces cerevisiae in gametes to that of mitotic cells. Gametes contain a distinct INM proteome needed to complete gamete formation, including expression of genes linked to cell wall biosynthesis, lipid biosynthetic and metabolic pathways, protein degradation, and unknown functions. Based on the inheritance pattern, INM components are made de novo in the gametes. Whereas mitotic cells show a strong preference for proteins with small extraluminal domains, gametes do not exhibit this size preference likely due to the changes in the nuclear permeability barrier during gametogenesis. Taken together, our data provide evidence for INM changes during gametogenesis and shed light on mechanisms used to shape the INM proteome of spores.

scholarly journals A distinct inner nuclear membrane proteome in Saccharomyces cerevisiae gametes

2021 ◽  
Author(s):  
Shary N Shelton ◽  
Sarah E. Smith ◽  
Jay R. Unruh ◽  
Sue L. Jaspersen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Membrane ◽  
De Novo ◽  
Protein Composition ◽  
Permeability Barrier ◽  
Developmentally Regulated ◽  
Inner Nuclear Membrane ◽  
Expression Of Genes ◽  
Size Preference ◽  
Mitotic Cells

The inner nuclear membrane (INM) proteome regulates gene expression, chromatin organization, and nuclear transport, however, it is poorly understood how changes in INM protein composition contribute to developmentally regulated processes, such as gametogenesis. Using a split-GFP complementation system, we compared the distribution of all C-terminally tagged transmembrane proteins in Saccharomyces cerevisiae in gametes to that of mitotic cells. Gametes contain a distinct INM proteome needed to complete gamete formation, including expression of genes linked to cell wall biosynthesis, lipid biosynthetic and metabolic pathways, protein degradation and unknown functions. Based on the inheritance pattern, INM components are made de novo in the gametes. Whereas mitotic cells show a strong preference for proteins with small extraluminal domains, gametes do not exhibit this size preference likely due to the changes in the nuclear permeability barrier during gametogenesis.

scholarly journals Asi1 regulates the distribution of proteins at the inner nuclear membrane in Saccharomyces cerevisiae

2018 ◽  
Author(s):  
Christine J. Smoyer ◽  
Sarah E. Smith ◽  
Scott McCroskey ◽  
Jay R. Unruh ◽  
Sue L. Jaspersen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Membrane ◽  
Protein Turnover ◽  
Protein Quality ◽  
E3 Ligase ◽  
Protein Composition ◽  
Degradation Pathways ◽  
Wild Type ◽  
Inner Nuclear Membrane ◽  
Protein Levels

AbstractInner nuclear membrane (INM) protein composition regulates nuclear function, affecting processes such as gene expression, chromosome organization, nuclear shape and stability. Mechanisms that drive changes in the INM proteome are poorly understood in part because it is difficult to definitively assay INM composition rigorously and systematically. Using a split-GFP complementation system to detect INM access, we examined the distribution of all C-terminally tagged Saccharomyces cerevisiae membrane proteins in wild-type cells and in mutants affecting protein quality control pathways, such as INM-associated degradation (INMAD), ER-associated degradation (ERAD) and vacuolar proteolysis. Deletion of the E3 ligase Asi1 had the most pronounced effect on the INM compared to mutants in vacuolar or ER-associated degradation pathways, consistent with a role for Asi1 in the INMAD pathway. Our data suggests that Asi1 not only removes mis-targeted proteins at the INM, but it also controls the levels and distribution of native INM components, such as the membrane nucleoporin Pom33. Interestingly, loss of Asi1 does not affect Pom33 protein levels but instead alters Pom33 distribution in the NE through Pom33 ubiquitination, which drives INM redistribution. Taken together, our data demonstrate that the Asi1 E3 ligase has a novel function in INM protein regulation in addition to protein turnover.

scholarly journals The fates of chicken nuclear lamin proteins during mitosis: evidence for a reversible redistribution of lamin B2 between inner nuclear membrane and elements of the endoplasmic reticulum.

1988 ◽  
Vol 107 (2) ◽  
pp. 397-406 ◽  
Author(s):  
R Stick ◽  
B Angres ◽  
C F Lehner ◽  
E A Nigg
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Membrane Vesicles ◽  
Soluble Form ◽  
Lamin A ◽  
Cell Fractionation ◽  
Lamin B ◽  
Inner Nuclear Membrane ◽  
Nuclear Lamin ◽  
Mitotic Cells

In chicken, three structurally distinct nuclear lamin proteins have been described. According to their migration on two-dimensional gels, these proteins have been designated as lamins A, B1, and B2. To investigate the functional relationship between chicken lamins and their mammalian counterparts, we have examined here the state of individual chicken lamin proteins during mitosis. Current models proposing functional specializations of mammalian lamin subtypes are in fact largely based on the observation that during mitosis mammalian lamin B remains associated with membrane vesicles, whereas lamins A and C become freely soluble. Cell fractionation experiments combined with immunoblotting show that during mitosis both chicken lamins B1 and B2 remain associated with membranes, whereas lamin A exists in a soluble form. In situ immunoelectron microscopy carried out on mitotic cells also reveals membrane association of lamin B2, whereas the distribution of lamin A is random. From these results we conclude that both chicken lamins B1 and B2 may functionally resemble mammalian lamin B. Interestingly, immunolabeling of mitotic cells revealed an association of lamin B2 with extended membrane cisternae that resembled elements of the endoplasmic reticulum. Quantitatively, we found that all large endoplasmic reticulum-like membranes present in metaphase cells were decorated with lamin B2-specific antibodies. Given that labeling of these mitotic membranes was lower than labeling of interphase nuclear envelopes, it appears likely that during mitotic disassembly and reassembly of the nuclear envelope lamin B2 may reversibly distribute between the inner nuclear membrane and the endoplasmic reticulum.

scholarly journals Alternative Modes of Organellar Segregation during Sporulation in Saccharomyces cerevisiae

2007 ◽  
Vol 6 (11) ◽  
pp. 2009-2017 ◽  
Author(s):  
Yasuyuki Suda ◽  
Hideki Nakanishi ◽  
Erin M. Mathieson ◽  
Aaron M. Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Plasma Membranes ◽  
De Novo ◽  
Leading Edge ◽  
Protein Coat ◽  
Prospore Membrane ◽  
Cortical Endoplasmic Reticulum ◽  
Mitotic Cells

ABSTRACT Formation of ascospores in the yeast Saccharomyces cerevisiae is driven by an unusual cell division in which daughter nuclei are encapsulated within de novo-formed plasma membranes, termed prospore membranes. Generation of viable spores requires that cytoplasmic organelles also be captured along with nuclei. In mitotic cells segregation of mitochondria into the bud requires a polarized actin cytoskeleton. In contrast, genes involved in actin-mediated transport are not essential for sporulation. Instead, efficient segregation of mitochondria into spores requires Ady3p, a component of a protein coat found at the leading edge of the prospore membrane. Other organelles whose mitotic segregation is promoted by actin, such as the vacuole and the cortical endoplasmic reticulum, are not actively segregated during sporulation but are regenerated within spores. These results reveal that organellar segregation into spores is achieved by mechanisms distinct from those in mitotic cells.

scholarly journals Distribution of Proteins at the Inner Nuclear Membrane Is Regulated by the Asi1 E3 Ligase in Saccharomyces cerevisiae

Genetics ◽  
2019 ◽  
Vol 211 (4) ◽  
pp. 1269-1282 ◽  
Author(s):  
Christine J. Smoyer ◽  
Sarah E. Smith ◽  
Jennifer M. Gardner ◽  
Scott McCroskey ◽  
Jay R. Unruh ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Membrane ◽  
E3 Ligase ◽  
Inner Nuclear Membrane

scholarly journals Loss of a-Type Lamin Expression Compromises Nuclear Envelope Integrity Leading to Muscular Dystrophy

1999 ◽  
Vol 147 (5) ◽  
pp. 913-920 ◽  
Author(s):  
Teresa Sullivan ◽  
Diana Escalante-Alcalde ◽  
Harshida Bhatt ◽  
Miriam Anver ◽  
Narayan Bhat ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Mammalian Cells ◽  
Nuclear Architecture ◽  
Nuclear Lamina ◽  
Postnatal Growth ◽  
Developmentally Regulated ◽  
Inner Nuclear Membrane ◽  
Cardiac Muscles

The nuclear lamina is a protein meshwork lining the nucleoplasmic face of the inner nuclear membrane and represents an important determinant of interphase nuclear architecture. Its major components are the A- and B-type lamins. Whereas B-type lamins are found in all mammalian cells, A-type lamin expression is developmentally regulated. In the mouse, A-type lamins do not appear until midway through embryonic development, suggesting that these proteins may be involved in the regulation of terminal differentiation. Here we show that mice lacking A-type lamins develop to term with no overt abnormalities. However, their postnatal growth is severely retarded and is characterized by the appearance of muscular dystrophy. This phenotype is associated with ultrastructural perturbations to the nuclear envelope. These include the mislocalization of emerin, an inner nuclear membrane protein, defects in which are implicated in Emery-Dreifuss muscular dystrophy (EDMD), one of the three major X-linked dystrophies. Mice lacking the A-type lamins exhibit tissue-specific alterations to their nuclear envelope integrity and emerin distribution. In skeletal and cardiac muscles, this is manifest as a dystrophic condition related to EDMD.

scholarly journals Lipid and protein dynamics that shape nuclear envelope identity

2020 ◽  
Vol 31 (13) ◽  
pp. 1315-1323 ◽  
Author(s):  
Shirin Bahmanyar ◽  
Christian Schlieker
Keyword(s):  
Nuclear Envelope ◽  
Membrane Fusion ◽  
Lipid Bilayers ◽  
De Novo ◽  
Lipid Synthesis ◽  
Protein Composition ◽  
Nuclear Pore ◽  
Permeability Barrier ◽  
Unique Composition ◽  
New Evidence

The nuclear envelope (NE) is continuous with the endoplasmic reticulum (ER), yet the NE carries out many functions distinct from those of bulk ER. This functional specialization depends on a unique protein composition that defines NE identity and must be both established and actively maintained. The NE undergoes extensive remodeling in interphase and mitosis, so mechanisms that seal NE holes and protect its unique composition are critical for maintaining its functions. New evidence shows that closure of NE holes relies on regulated de novo lipid synthesis, providing a link between lipid metabolism and generating and maintaining NE identity. Here, we review regulation of the lipid bilayers of the NE and suggest ways to generate lipid asymmetry across the NE despite its direct continuity with the ER. We also discuss the elusive mechanism of membrane fusion during nuclear pore complex (NPC) biogenesis. We propose a model in which NPC biogenesis is carefully controlled to ensure that a permeability barrier has been established before membrane fusion, thereby avoiding a major threat to compartmentalization.

Lamin B receptor: role on chromatin structure, cellular senescence and possibly aging

2020 ◽  
Vol 477 (14) ◽  
pp. 2715-2720
Author(s):  
Susana Castro-Obregón
Keyword(s):  
Cellular Senescence ◽  
Nuclear Membrane ◽  
Chromatin Structure ◽  
Cholesterol Synthesis ◽  
Reductase Activity ◽  
Chimeric Protein ◽  
Nuclear Lamina ◽  
Lamin B ◽  
Inner Nuclear Membrane ◽  
Lamin B Receptor

The nuclear envelope is composed by an outer nuclear membrane and an inner nuclear membrane, which is underlain by the nuclear lamina that provides the nucleus with mechanical strength for maintaining structure and regulates chromatin organization for modulating gene expression and silencing. A layer of heterochromatin is beneath the nuclear lamina, attached by inner nuclear membrane integral proteins such as Lamin B receptor (LBR). LBR is a chimeric protein, having also a sterol reductase activity with which it contributes to cholesterol synthesis. Lukasova et al. showed that when DNA is damaged by ɣ-radiation in cancer cells, LBR is lost causing chromatin structure changes and promoting cellular senescence. Cellular senescence is characterized by terminal cell cycle arrest and the expression and secretion of various growth factors, cytokines, metalloproteinases, etc., collectively known as senescence-associated secretory phenotype (SASP) that cause chronic inflammation and tumor progression when they persist in the tissue. Therefore, it is fundamental to understand the molecular basis for senescence establishment, maintenance and the regulation of SASP. The work of Lukasova et al. contributed to our understanding of cellular senescence establishment and provided the basis that lead to the further discovery that chromatin changes caused by LBR reduction induce an up-regulated expression of SASP factors. LBR dysfunction has relevance in several diseases and possibly in physiological aging. The potential bifunctional role of LBR on cellular senescence establishment, namely its role in chromatin structure together with its enzymatic activity contributing to cholesterol synthesis, provide a new target to develop potential anti-aging therapies.

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