scholarly journals Smooth ER Function And Rough ER Function

2018 ◽  
Author(s):  
Daniel Nelson
Keyword(s):  
Rough Er

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

scholarly journals Mitochondria-rough-ER contacts in the liver regulate systemic lipid homeostasis

Cell Reports ◽  
2021 ◽  
Vol 34 (11) ◽  
pp. 108873
Author(s):  
Irene Anastasia ◽  
Nicolò Ilacqua ◽  
Andrea Raimondi ◽  
Philippe Lemieux ◽  
Rana Ghandehari-Alavijeh ◽  
...  
Keyword(s):  
Lipid Homeostasis ◽  
Rough Er

scholarly journals 180-kD ribosome receptor is essential for both ribosome binding and protein translocation.

1993 ◽  
Vol 120 (4) ◽  
pp. 853-863 ◽  
Author(s):  
A J Savitz ◽  
D I Meyer
Keyword(s):  
Monoclonal Antibodies ◽  
Direct Evidence ◽  
Protein Translocation ◽  
Secretory Protein ◽  
Ribosome Binding ◽  
Fab Fragments ◽  
Rough Er

We have previously isolated a 180-kD ribosome receptor (p180) from mammalian rough ER that, when incorporated into liposomes, bound ribosomes with an affinity similar to intact membranes. To directly assess the contribution of p180 to ribosome binding as well as protein translocation, monoclonal antibodies were used to selectively deplete p180 from the detergent extracts of rough ER membranes used in the preparation of translocation-competent proteoliposomes. Proteoliposomes prepared from p180-depleted extracts showed a reduction in ribosome binding to the level of trypsin-inactivated controls as well as a loss in their ability to cotranslationally translocate two different secretory protein precursors. When purified p180 was added back to depleted extracts before proteoliposome formation, both ribosome binding and translocation activity were restored. In addition, the monoclonal antibodies, as well as their Fab' fragments, were able to inhibit ribosome binding and protein translocation when bound to intact rough microsomes. These data provide direct evidence that the 180-kD ribosome receptor is essential for ribosome binding and for the translocation of nascent proteins across the membrane of the rough ER.

How the parasitic bacterium Legionella pneumophila modifies its phagosome and transforms it into rough ER: implications for conversion of plasma membrane to the ER membrane

2001 ◽  
Vol 114 (24) ◽  
pp. 4637-4650 ◽  
Author(s):  
Lewis G. Tilney ◽  
Omar S. Harb ◽  
Patricia S. Connelly ◽  
Camenzind G. Robinson ◽  
Craig R. Roy
Keyword(s):  
Legionella Pneumophila ◽  
Mitochondrial Membranes ◽  
Macrophage Infection ◽  
Thin Sections ◽  
Stage Process ◽  
Legionnaires Disease ◽  
Rough Er ◽  
Membrane Changes ◽  
Phagosomal Membrane

Within five minutes of macrophage infection by Legionella pneumophila, the bacterium responsible for Legionnaires’ disease, elements of the rough endoplasmic reticulum (RER) and mitochondria attach to the surface of the bacteria-enclosed phagosome. Connecting these abutting membranes are tiny hairs, which are frequently periodic like the rungs of a ladder. These connections are stable and of high affinity - phagosomes from infected macrophages remain connected to the ER and mitochondria (as they were in situ) even after infected macrophages are homogenized. Thin sections through the plasma and phagosomal membranes show that the phagosomal membrane is thicker (72±2 Å) than the ER and mitochondrial membranes (60±2 Å), presumably owing to the lack of cholesterol, sphingolipids and glycolipids in the ER. Interestingly, within 15 minutes of infection, the phagosomal membrane changes thickness to resemble that of the attached ER vesicles. Only later (e.g. after six hours) does the ER-phagosome association become less frequent. Instead ribosomes stud the former phagosomal membrane and L. pneumophila reside directly in the rough ER. Examination of phagosomes of various L. pneumophila mutants suggests that this membrane conversion is a four-stage process used by L. pneumophila to establish itself in the RER and to survive intracellularly. But what is particularly interesting is that L. pneumophila is exploiting a poorly characterized naturally occuring cellular process.

scholarly journals Characterization of the budding compartment of mouse hepatitis virus: evidence that transport from the RER to the Golgi complex requires only one vesicular transport step

1994 ◽  
Vol 124 (1) ◽  
pp. 55-70 ◽  
Author(s):  
J Krijnse-Locker ◽  
M Ericsson ◽  
PJ Rottier ◽  
G Griffiths
Keyword(s):  
Golgi Complex ◽  
Hepatitis Virus ◽  
Vesicular Transport ◽  
Helix Pomatia ◽  
M Protein ◽  
Membrane Structures ◽  
Golgi Stack ◽  
Permeabilized Cells ◽  
Intermediate Compartment ◽  
Rough Er

Mouse hepatitis coronavirus (MHV) buds into pleomorphic membrane structures with features expected of the intermediate compartment between the ER and the Golgi complex. Here, we characterize the MHV budding compartment in more detail in mouse L cells using streptolysin O (SLO) permeabilization which allowed us to better visualize the membrane structures at the ER-Golgi boundary. The MHV budding compartment shares membrane continuities with the rough ER as well as with cisternal elements on one side of the Golgi stack. It also labeled with p58 and rab2, two markers of the intermediate compartment, and with PDI, usually considered to be a marker of the rough ER. The membranes of the budding compartment, as well as the budding virions themselves, but not the rough ER, labeled with the N-acetyl-galactosamine (GalNAc)-specific lectin Helix pomatia. When the SLO-permeabilized cells were treated with guanosine 5'-(3-O-thio)triphosphate (GTP gamma S), the budding compartment accumulated a large number of beta-cop-containing buds and vesicular profiles. Complementary biochemical experiments were carried out to determine whether vesicular transport was required for the newly synthesized M protein, that contains only O-linked oligosaccharides, to acquire first, GalNAc and second, the Golgi modifications galactose and sialic acid. The results from both in vivo studies and from the use of SLO-permeabilized cells showed that, while GalNAc addition occurred under conditions which block vesicular transport, both cytosol and ATP were prerequisites for the M protein oligosaccharides to acquire Golgi modifications. Collectively, our data argue that transport from the rough ER to the Golgi complex requires only one vesicular transport step and that the intermediate compartment is a specialized domain of the endoplasmatic reticulum that extends to the first cisterna on the cis side of the Golgi stack.

The AMF-R tubule is a smooth ilimaquinone-sensitive subdomain of the endoplasmic reticulum

1997 ◽  
Vol 110 (24) ◽  
pp. 3043-3053 ◽  
Author(s):  
H.J. Wang ◽  
N. Benlimame ◽  
I. Nabi
Keyword(s):  
Electron Microscopy ◽  
Confocal Microscopy ◽  
Immunofluorescence Microscopy ◽  
Mdck Cells ◽  
Autocrine Motility Factor ◽  
Motility Factor ◽  
Membranous Tubule ◽  
Intermediate Compartment ◽  
Rough Er ◽  
Golgi Network

Autocrine motility factor receptor (AMF-R) is a marker for a distinct smooth membranous tubule. Ilimaquinone (IQ) is a sea sponge metabolite which induces the complete vesiculation of the Golgi apparatus and we show here that the addition of IQ to MDCK cells also results in the disruption of the AMF-R tubule. By immunofluorescence microscopy, the resultant punctate AMF-R label resembles the products of IQ-mediated vesiculation of the trans-Golgi network, however, the two labels can be distinguished by confocal microscopy. AMF-R tubule fragmentation occurs after nocodazole or taxol treatment of the cells demonstrating that the action of IQ on AMF-R tubules is not related to the ability of IQ to depolymerize microtubules. IQ activity is therefore not Golgi-specific. Electron microscopy of IQ-treated cells reveals that AMF-R is distributed to fenestrated networks of narrow interconnected tubules which are distinguishable from the uniform Golgi-derived vesicles and morphologically equivalent to smooth ER. Distinct fenestrations are visible in incompletely fragmented tubules which may represent intermediates in the fragmentation process. Smooth AMF-R labeled tubules exhibit continuity with rough ER cisternae and IQ selectively targets smooth and not rough ER. AMF-R tubules can be distinguished from the intermediate compartment labeled for ERGIC-53 by confocal microscopy and thus constitute a distinct IQ-sensitive subdomain of the smooth ER.

scholarly journals XBP1

2004 ◽  
Vol 167 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Rungtawan Sriburi ◽  
Suzanne Jackowski ◽  
Kazutoshi Mori ◽  
Joseph W. Brewer
Keyword(s):  
Active Form ◽  
Membrane Phospholipids ◽  
Unfolded Protein ◽  
Xbp1 Mrna ◽  
Phosphatidylcholine Biosynthesis ◽  
Rough Er ◽  
The Unfolded Protein Response ◽  
Protein Response ◽  
Er Homeostasis ◽  
Area And Volume

When the protein folding capacity of the endoplasmic reticulum (ER) is challenged, the unfolded protein response (UPR) maintains ER homeostasis by regulating protein synthesis and enhancing expression of resident ER proteins that facilitate protein maturation and degradation. Here, we report that enforced expression of XBP1(S), the active form of the XBP1 transcription factor generated by UPR-mediated splicing of XBP1 mRNA, is sufficient to induce synthesis of phosphatidylcholine, the primary phospholipid of the ER membrane. Cells overexpressing XBP1(S) exhibit elevated levels of membrane phospholipids, increased surface area and volume of rough ER, and enhanced activity of the cytidine diphosphocholine pathway of phosphatidylcholine biosynthesis. These data suggest that XBP1(S) links the mammalian UPR to phospholipid biosynthesis and ER biogenesis.

scholarly journals Knockdown of p180 Eliminates the Terminal Differentiation of a Secretory Cell Line

2009 ◽  
Vol 20 (2) ◽  
pp. 732-744 ◽  
Author(s):  
Payam Benyamini ◽  
Paul Webster ◽  
David I. Meyer
Keyword(s):  
Cell Line ◽  
Mammalian Cells ◽  
Secretory Cell ◽  
Terminal Differentiation ◽  
Secretory Cells ◽  
Rnai Technology ◽  
Apo E ◽  
Secretory Phenotype ◽  
Rough Er ◽  
Necessary And Sufficient

We have previously reported that the expression in yeast of an integral membrane protein (p180) of the endoplasmic reticulum (ER), isolated for its ability to mediate ribosome binding, is capable of inducing new membrane biogenesis and an increase in secretory capacity. To demonstrate that p180 is necessary and sufficient for terminal differentiation and acquisition of a secretory phenotype in mammalian cells, we studied the differentiation of a secretory cell line where p180 levels had been significantly reduced using RNAi technology and by transiently expressing p180 in nonsecretory cells. A human monocytic (THP-1) cell line, that can acquire macrophage-like properties, failed to proliferate rough ER when p180 levels were lowered. The Golgi compartment and the secretion of apolipoprotein E (Apo E) were dramatically affected in cells expressing reduced p180 levels. On the other hand, expression of p180 in a human embryonic kidney nonsecretory cell line (HEK293) showed a significant increase in proliferation of rough ER membranes and Golgi complexes. The results obtained from knockdown and overexpression experiments demonstrate that p180 is both necessary and sufficient to induce a secretory phenotype in mammalian cells. These findings support a central role for p180 in the terminal differentiation of secretory cells and tissues.

Changes in the plant endomembrane system associated with callose synthesis during the interaction between cowpea (Vigna unguiculata) and the cowpea rust fungus (Uromyces vignae)

1995 ◽  
Vol 73 (11) ◽  
pp. 1731-1738 ◽  
Author(s):  
Dubravka Škalamera ◽  
Michèle C. Heath
Keyword(s):  
Endoplasmic Reticulum ◽  
Vigna Unguiculata ◽  
De Novo ◽  
Rust Fungus ◽  
Leaf Tissue ◽  
Resistant Cultivar ◽  
Callose Deposition ◽  
Golgi Membranes ◽  
Rough Er ◽  
Uromyces Vignae

Electron microscopy and stereological analysis of cowpea (Vigna unguiculata) leaf tissue infected with the cowpea rust fungus (Uromyces vignae) revealed an increase in surface of plant endomembranes that was associated with callose synthesis or the presence of fungal haustoria. In the resistant cultivar in which the haustorium commonly becomes encased, an increase in surface of smooth membranes was observed in cytoplasmic regions adjacent to developing encasements compared with the regions away from the fungus or with any region in infected or uninfected callose nonsynthesizing cells. Cytoplasmic regions adjacent to the haustorium in callose nonsynthesizing cells had an increase in rough endoplasmic reticulum (ER). This increase was greater in a susceptible cultivar than in the resistant cultivar that was treated with tunicamycin to inhibit callose synthesis. In the latter situation, the lack of callose encasement allowed the haustorial neckband to form, but other ultrastructural signs of incompatibility remained, such as the presence of electron-opaque material associated with the extrahaustorial membrane. No differences between cultivars or treatments were observed in Golgi membranes. Our observations suggest that both callose synthesis and fungal presence are associated with de novo synthesis of membranes; callose deposition may require an increase in smooth membranes of uncertain origin, whereas the establishment of a haustorium may be dependent on increased synthesis of rough ER. Key words: callose, endoplasmic reticulum, resistance, stereology, tunicamycin.

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