Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Considerable advances in our understanding of the molecular pathology of the major human neurodegenerative diseases have been made by the use of ubiquitin immunocytochemistry. The technique demonstrates that filamentous inclusions and vacuoles contain ubiquitin-protein conjugates. The molecular structure of the filaments and the morphological type of vacuoles is not completely understood but there is evidence that some of the filamentous inclusions contain intermediate filaments and the perinuclear distribution of the vacuoles resemble the distribution of intraneuronal lysosomes. Intermediate filaments and lysosomes are involved in the sequestration and degradation of viral membrane proteins in tissue culture cells. Immunogold electron microscopical and biochemical evidence indicates that ubiquitin-protein conjugates are normally considerably enriched in the lysosomes of fibroblasts relative to all other organelles. Immunogold electron microscopy shows a similar enrichment of ubiquitin-protein conjugates in the dense lysosomes of granulocytic precursor cells in the bone marrow. Filamentous inclusions showing several of the features seen in inclusions in the neurodegenerative diseases are seen in Epstein-Barr virus transformed lymphoblastoid cells. Immunohistochemistry shows that the inclusions contain vimentin intermediate filaments, the latent membrane transforming protein of the virus, ubiquitin-protein conjugates, and a heat-shock protein 70 (hsp 70). Immunohistochemistry and immunogold electron microscopy demonstrate that the latent membrane protein, ubiquitin-protein conjugates and hsp 70 are in lysosomes entwined in an intermediate filament cage centred on the microtubule organising centre. The implications of the combined observations for our understanding of the cell stress response in degenerating neurones and in virally infected cells are discussed.
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PMID:Ubiquitin and the lysosome system: molecular immunopathology reveals the connection. 166 79

Monoclonal antibodies were generated against detergent-insoluble cytoskeletal proteins isolated from low-density membrane fractions of rat liver. By immunofluorescence, one of the antibodies stains three distinct structures in cultured rat fibroblast and hepatocyte lines as well as the PtK2 rat-kangaroo kidney epithelial line. These structures are: i) many tangled filaments similar to intermediate filaments (IFs), ii) fewer and variable numbers of straight filaments, and iii) punctate cytoplasmic foci, often most intense around the nucleus. All three of these structures are resistant to extraction by non-ionic detergent. Close examination reveals that the tangled and straight filaments are not stained uniformly, but as a series of bright patches. In cells treated with nocodazole, the antibody reacts strongly with a perinuclear filamentous cage. Very few tangled filaments are detected in these cells, however, the straight filaments and punctate cytoplasmic staining are resistant to nocodazole treatment. Double-label immunofluorescence shows that, even though tangled filament distribution and nocodazole sensitivity are similar to the behavior of vimentin IFs, there is only partial coincidence of staining with either vimentin or cytokeratin IFs. The straight filaments coincide with some actin stress fibers, but the punctate cytoplasmic staining is not related to IFs, actin, or tubulin. Thus, this monoclonal antibody stains a novel group of three seemingly unrelated cytoskeletal structures, including a previously undescribed insoluble nonfilamentous pool. Taken as a whole, two hypotheses are consistent with these data. i) The antigen recognized may be a protein which has a large insoluble cytoplasmic pool and binds both IFs and actin, but only binds to a subset of each class of filaments.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:On the relation between distinct components of the cytoskeleton: an epitope shared by intermediate filaments, microfilaments and cytoplasmic foci. 169 74

Immunofluorescence microscopy was used to follow the rearrangement of keratin filaments and vimentin filaments during mitosis in Vero and HeLa cell lines. The experiment results showed that the three dimensional organization and structure of intermediate filaments changed drastically during mitosis. The behavior of intermediate filaments was different in these two epithelial cell lines. In mitotic Vero cells the keratin filaments and vimentin filaments maintained their filamentous structure and formed a cage around the mitotic apparatus. In mitotic HeLa cells the keratin filaments and vimentin filaments reorganized extensively and formed granular cytoplasmic bodies. The ratio of granular cytoplasmic body formation changed in different mitotic phase. The interphase intermediate filament network was reconstructed after mitosis. It is proposed that the state of intermediate filament network in these cells is cell cycle-dependent and intermediate filaments may have some skeletal role in mitosis.
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PMID:[Changes of intermediate filament during mitosis in two epithelial cell lines]. 170 41

The E6 and E7 genes of the cancer-associated human papillomavirus (HPV) types 16 (HPV16) and 18 (HPV18) can induce cell immortalization in vitro in normal human keratinocytes. This, however, is not associated with tumorigenicity in vivo. On the other hand, tumorigenicity of HPV18-positive HeLa cervical carcinoma cells can be suppressed by fusion of HeLa cells with normal human keratinocytes or fibroblasts. We have addressed the question of whether suppression of tumorigenicity in HeLa x fibroblast hybrid cells might be due to a reduced ability of these cells to express the HPV18 E6-E7 genes in vivo. Nontumorigenic hybrid cells and tumorigenic hybrid segregants were transplanted as organotypical cultures or injected subcutaneously into immunocompromised mice and were analyzed for HPV18 E6-E7 gene expression by RNA-RNA in situ hybridization. The tumorigenic hybrid cells showed a continuous and invasive growth that was associated with high levels of HPV18 E6-E7 mRNAs at all time points examined. In contrast, the nontumorigenic hybrid cells stopped cell proliferation approximately 3 days after transplantation. At this time they expressed the E6-E7 genes at low levels, whereas at day 2 high expression levels were observed. However, the mRNA levels of the cytoskeletal genes beta-actin and vimentin remained high for at least 14 days, demonstrating that inhibition of growth and of HPV18 E6-E7 gene expression was not due to cell death. These results suggest that growth inhibition of the nontumorigenic HeLa x fibroblast hybrid cells in vivo might be caused by suppression of HPV18 E6-E7 gene expression and are compatible with the idea of an intracellular surveillance mechanism for HPV gene expression existing in nontumorigenic cells.
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PMID:Suppression in vivo of human papillomavirus type 18 E6-E7 gene expression in nontumorigenic HeLa X fibroblast hybrid cells. 216 62

Fluorescently labeled desmin was incorporated into intermediate filaments when microinjected into living tissue culture cells. The desmin, purified from chicken gizzard smooth muscle and labeled with the fluorescent dye iodoacetamido rhodamine, was capable of forming a network of 10-nm filaments in solution. The labeled protein associated specifically with the native vimentin filaments in permeabilized, unfixed interphase and mitotic PtK2 cells. The labeled desmin was microinjected into living, cultured embryonic skeletal myotubes, where it became incorporated in straight fibers aligned along the long axis of the myotubes. Upon exposure to nocodazole, microinjected myotubes exhibited wavy, fluorescent filament bundles around the muscle nuclei. In PtK2 cells, an epithelial cell line, injected desmin formed a filamentous network, which colocalized with the native vimentin intermediate filaments but not with the cytokeratin networks and microtubular arrays. Exposure of the injected cells to nocadazole or acrylamide caused the desmin network to collapse and form a perinuclear cap that was indistinguishable from vimentin caps in the same cells. During mitosis, labeled desmin filaments were excluded from the spindle area, forming a cage around it. The filaments were partitioned into two groups either during anaphase or at the completion of cytokinesis. In the former case, the perispindle desmin filaments appeared to be stretched into two parts by the elongating spindle. In the latter case, a continuous bundle of filaments extended along the length of the spindle and appeared to be pinched in two by the contracting cleavage furrow. In these cells, desmin filaments were present in the midbody where they gradually were removed as the desmin filament network became redistributed throughout the cytoplasm of the spreading daughter cells.
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PMID:Visualization of intermediate filaments in living cells using fluorescently labeled desmin. 265 44

We have used immunofluorescence staining with antibodies that detect vimentin, tubulin and the centrioles to compare the distributions of these respective antigens during the division of several suspension and attached cultured cells. Our observations demonstrate that 1) from distinct interphase organizations in suspension and attached cells, the vimentin system consistently rearranges with the onset of mitosis into a filamentous cage-like structure enclosing the spindle, 2) during cytokinesis, the polar centrosomes relocalize near the midbody in suspension cells while they remain at the pole opposite to it in attached cells, and 3) the vimentin cage is disintegrated and aggregated on each side of the midbody during cytokinesis in lymphoid cells but may be retained in other suspension cells.
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PMID:Organization of the vimentin system and its spatial relationship to the microtubule complex during the division of mammalian cells growing attached and in suspension. 275 1

Mitotic spindles were isolated from Chinese hamster ovary (CHO) cells and examined morphologically and biochemically. The isolated spindles were observed to be intact structures containing associated chromosomes and were surrounded by a cage of vimentin-containing filaments. Two-dimensional gel electrophoresis of isolated spindles versus whole cell homogenates indicated that isolated spindles were free from significant cytoplasmic contamination and contained tubulin, actin, vimentin and an 80 X 10(3) Mr quadrapeptide as their major protein constituents. Five calmodulin-binding proteins with molecular weights of 200, 160, 130, 60 and 52 (X 10(3] Mr were identified within isolated spindles. These calmodulin-binding proteins may be involved in regulating microtubule organization and depolymerization during karyokinesis.
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PMID:Biochemical characterization of isolated CHO cell mitotic spindles: identification of calmodulin-binding proteins. 331 52

We have used double immunofluorescence and electron microscopy to examine the distribution of tubulin and vimentin during the stimulation of mouse splenic lymphocytes by the mitogen concanavalin A. In unstimulated cells, vimentin forms a filamentous network partially coincident with the radial pattern of microtubules. In stimulated cells, the numbers of microtubules assembled from the centrosome have increased and vimentin is organized as an aggregate located near the centrosome. When these cells enter mitosis, vimentin is arranged into a filamentous cage enclosing the mitotic apparatus. During cytokinesis, the polar centrosomes are observed at a position adjacent to the midbody and vimentin is detected as an aggregate, similar to that seen prior to mitosis, close to the centrosome in each daughter cell. Using several agents, such as colchicine, colcemid, nocodazole, and taxol, which affect microtubule assembly, we have observed that the vimentin system, although closely related spatially to the microtubule complex in lymphocytes, can still reorganize independently as these cells progress through the cell cycle. Throughout mitogenic stimulation in the continued presence of taxol, microtubules are reorganized into a few thick bundles while the vimentin system undergoes a sequence of rearrangements similar to those observed during normal stimulation. These data suggest that vimentin dynamics may be important in the progression of lymphocytes through the cell cycle in response to mitogen.
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PMID:Vimentin dynamics during the mitogenic stimulation of mouse splenic lymphocytes. 331 97

During adipose conversion of murine 3T3-L1 cells, the arrangement of vimentin intermediate filaments (IFs) changes from an extended fibrillar state to a complex cage formation tightly associated with the forming lipid globules. The fully developed cage complex surrounding the lipid globule consists of a monolayer of groups of regularly spaced vimentin IFs that in turn is closely ensheathed by a special endoplasmic reticulum cisterna. The same IF cage is also seen in other adipocytes in culture and in tissues. The specificity of the association of lipid globules with vimentin IFs during adipose conversion is discussed as a special form of compartmentalization supporting adipogenesis and is taken as an example of a possible IF function in relation to a cell differentiation process.
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PMID:Rearrangement of the vimentin cytoskeleton during adipose conversion: formation of an intermediate filament cage around lipid globules. 354 99

Mitotic BHK21 cells were examined by immunofluorescence optical sectioning after staining with anti-vimentin. Throughout all stages of mitosis, intact 10-nm filaments were observed to form a cage around the mitotic spindle. These observations were confirmed by serial section electron microscopy which demonstrated assembled 10-nm filaments in the cytoplasm surrounding the spindle. Therefore, in contrast to previous reports, mitotic BHK21 cells show a similar cage-like 10-nm filament arrangement, as found in a variety of other cell types.
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PMID:Observations on the vimentin-10-NM filaments during mitosis in BHK21 cells. 675


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