The microfilament system in the formation of invasive adhesions

2008 ◽  
Vol 18 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Mario Gimona
Keyword(s):  
Microfilament System

NUANCE, a giant protein connecting the nucleus and actin cytoskeleton

2002 ◽  
Vol 115 (15) ◽  
pp. 3207-3222 ◽  
Author(s):  
Yen-Yi Zhen ◽  
Thorsten Libotte ◽  
Martina Munck ◽  
Angelika A. Noegel ◽  
Elena Korenbaum
Keyword(s):  
Actin Cytoskeleton ◽  
Transmembrane Domain ◽  
Coiled Coil ◽  
Peripheral Blood Lymphocytes ◽  
Binding Domain ◽  
Actin Binding ◽  
Actin Binding Domain ◽  
Microfilament System

NUANCE (NUcleus and ActiN Connecting Element) was identified as a novel protein with an α-actinin-like actin-binding domain. A human 21.8 kb cDNA of NUANCE spreads over 373 kb on chromosome 14q22.1-q22.3. The cDNA sequence predicts a 796 kDa protein with an N-terminal actin-binding domain, a central coiled-coil rod domain and a predicted C-terminal transmembrane domain. High levels of NUANCE mRNA were detected in the kidney, liver,stomach, placenta, spleen, lymphatic nodes and peripheral blood lymphocytes. At the subcellular level NUANCE is present predominantly at the outer nuclear membrane and in the nucleoplasm. Domain analysis shows that the actin-binding domain binds to Factin in vitro and colocalizes with the actin cytoskeleton in vivo as a GFP-fusion protein. The C-terminal transmembrane domain is responsible for the targeting the nuclear envelope. Thus, NUANCE is the firstα-actinin-related protein that has the potential to link the microfilament system with the nucleus.

Ultrastructural changes of lung capillary endothelium in response to botulinum C2toxin

1997 ◽  
Vol 82 (2) ◽  
pp. 382-388 ◽  
Author(s):  
L. Ermert ◽  
H.-R. Duncker ◽  
H. Brückner ◽  
F. Grimminger ◽  
T. Hansen ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Membrane ◽  
Structural Integrity ◽  
Ultrastructural Changes ◽  
Capillary Endothelium ◽  
High Dose ◽  
Edema Formation ◽  
Endothelial Layer ◽  
Total Weight Gain ◽  
Microfilament System

Ermert, L., H.-R. Duncker, H. Brückner, F. Grimminger, T. Hansen, R. Rössig, K. Aktories, and W. Seeger.Ultrastructural changes of lung capillary endothelium in response to botulinum C2toxin. J. Appl. Physiol. 82(2): 382–388, 1997.—The role of the endothelial cytoskeleton for the structural integrity of the pulmonary gas exchange area was probed with the use of Clostridium botulinumC2toxin. This agent causes selective loss of nonmuscle F-actin. In buffer-perfused rabbit lungs, vascular pressures were kept within physiological ranges. In different groups, low-dose [0.3 (C2,I)/0.6 (C2,II) ng/ml] and high-dose [10 (C2,I)/20 (C2,II) ng/ml] toxin were applicated into the buffer fluid; experiments were terminated after a total weight gain of either 1 or 7.5 g. Electron microscopy revealed extensive attenuations, undulations, and protrusions of the endothelial layer, suggestive of “remodeling” and “flowing” of the cell membrane in low C2toxin-treated lungs accompanied by few disruptions of the endothelial layer and edema formation. In addition, endothelial cells displayed vesiculation and bleb formation. Lungs that were exposed to high-toxin doses displayed marked attenuations of the endothelial layer in addition to large endothelial cell disruptions, which did not include interendothelial junctions. Interestingly, type II epithelial cells displayed fusion of lamellar bodies. Collectively, these data suggest that the actin microfilament system is instrumental in supporting endothelial cell membrane configuration and integrity and maintains the intimal barrier function of the lung microvasculature.

scholarly journals Organization of the actin filament cytoskeleton in the intestinal brush border: a quantitative and qualitative immunoelectron microscope study.

1988 ◽  
Vol 107 (3) ◽  
pp. 1037-1048 ◽  
Author(s):  
D Drenckhahn ◽  
R Dermietzel
Keyword(s):  
Brush Border ◽  
Actin Filaments ◽  
Close Association ◽  
Zonula Occludens ◽  
Terminal Web ◽  
Ultrathin Sections ◽  
Microfilament System ◽  
Human Intestinal Epithelium ◽  
Insight Into ◽  
Specific Label

In the present study we have used immunogold labeling of ultrathin sections of the intact chicken and human intestinal epithelium to obtain further insight into the molecular structure of the brush-border cytoskeleton. Actin, villin, and fimbrin were found within the entire microvillus filament bundle, from the tip to the basal end of the rootlets, but were virtually absent from the space between the rootlets. This suggests that the bulk of actin in the brush border is kept in a polymerized and cross-linked state and that horizontally deployed actin filaments are virtually absent. About 70% of the label specific for the 110-kD protein that links the microvillus core bundle to the lipid bilayer was found overlying the microvilli. The remaining label was associated with rootlets and the interrootlet space, where some label was regularly observed in association with vesicles. Since the terminal web did not contain any significant amounts of tubulin and microtubules, the present findings would support a recently proposed hypothesis that the 110-kD protein (which displays properties of an actin-activated, myosin-like ATPase) might also be involved in the transport of vesicles through the terminal web. Label specific for myosin and alpha-actinin was confined to the interrootlet space and was absent from the rootlets. About 10-15% of the myosin label and 70-80% of the alpha-actinin label was observed within the circumferential band of actin filaments at the zonula adherens, where myosin and alpha-actinin displayed a clustered, interrupted pattern that resembles the spacing of these proteins observed in other contractile systems. This circular filament ring did not contain villin, fimbrin, or the 110-kD protein. Finally, actin-specific label was observed in close association with the cytoplasmic aspect of the zonula occludens, suggesting that tight junctions are structurally connected to the microfilament system.

Immunochemical characterization of a new platelet specific monoclonal antibody and its use to demonstrate the cytoskeletal association of the platelet glycoprotein IIb-IIIa complex

1986 ◽  
Vol 6 (3) ◽  
pp. 323-333 ◽  
Author(s):  
Christopher Bird ◽  
Marion Callus ◽  
Lynne Trickett ◽  
Robin Thorpe
Keyword(s):  
Monoclonal Antibody ◽  
Fibroblast Cell ◽  
Cytoskeletal Proteins ◽  
Platelet Membrane ◽  
Platelet Glycoprotein ◽  
Membrane Glycoprotein ◽  
Polymorphonuclear Leucocytes ◽  
Microfilament System ◽  
Fibroblast Cell Lines

We describe the production and characterization of a monoclonal antibody specific for platelets. This antibody reacts strongly with human and primate platelets, but does not recognise human monocytes, polymorphonuclear leucocytes, lymphocytes, erythrocytes, leukaemic nor fibroblast cell lines, nor rodent platelets. Immunoprecipitation studies using radiolabelled platelet membrane proteins showed that the monoclonal antibody binds to the platelet membrane glycoprotein IIb-IIIa complex. Affinity chromatography using immobilized monoclonal antibody allows purification of the antigen, but also co-purifies the cytoskeletal proteins actin and myosin.Our results demonstrate immunochemically that although the GP IIb-IIIa complex is an external structure, it is connected through the cell membrane to the microfilament system.

Effect of polyamide nanoparticles on apoptosis of colon cancer cells induced by survivin antisense oligonucleotide

2020 ◽  
Vol 10 (9) ◽  
pp. 1573-1580
Author(s):  
Yongqiang Xu ◽  
Weibiao Ye ◽  
Chan Zhou ◽  
Yuling Li ◽  
Jianfang He
Keyword(s):  
Colon Cancer ◽  
Cancer Cells ◽  
P38 Mapk ◽  
Caspase 3 ◽  
Human Colon ◽  
Colon Cancer Cells ◽  
Human Colon Cancer ◽  
Significant Difference ◽  
Microfilament System ◽  
Human Colon Cancer Cells

In this study, we aimed to observe the effect of polyamidoamine (PAMAM) liposomes on the apoptosis of human colon cancer cells induced by survivin antisense oligonucleotides (ASODNs). PAMAM liposomes and PAMAM were mixed with survivin ASODNs to obtain antisense gene transfection complexes. In addition, the zeta potentials and encapsulation rates of the complexes were measured. The two gene-containing complexes were transfected into HT-29 colon cancer cells to observe changes in cell morphology, detect the inhibitory effect on tumor cells and changes in apoptosis, and observe changes in the cytoskeleton microfilament system using laser confocal microscopy. Caspase-3 activity in the cells was determined using a kinase activity assay, and p38 mitogen-activated protein kinase (p38 MAPK) activity in the cells was measured using immunoprecipitation analysis. The results showed that the zeta potential of the PAMAM liposome-survivin-ASODN complex was higher than that of the PAMAM-survivin-ASODN complex (P < 0.05). There was no significant difference in the gene encapsulation rates between the two complexes (P > 0.05). PAMAM liposomes may efficiently deliver survivin ASODNs to human colon cancer cells, reduce the expression of survivin protein and at the same time induce G2/M phase arrest in cells, and activate caspase-3 by activating p38 MAPK. Cleavage of caspase-3 destroys the structure of the intracellular skeletal microfilament system, finally resulting in apoptosis of colon cancer cells.

scholarly journals Ultrastructural localization of alpha-actinin and filamin in cultured cells with the immunogold staining (IGS) method.

1984 ◽  
Vol 99 (4) ◽  
pp. 1324-1334 ◽  
Author(s):  
G Langanger ◽  
J de Mey ◽  
M Moeremans ◽  
G Daneels ◽  
M de Brabander ◽  
...  
Keyword(s):  
Lung Epithelial Cells ◽  
Stress Fibers ◽  
Structural Basis ◽  
Cortical Networks ◽  
Specific Staining ◽  
Immunogold Staining ◽  
Chicken Heart ◽  
Dense Bodies ◽  
Microfilament System ◽  
Triton X

Monospecific antibodies to chicken gizzard actin, alpha-actinin, and filamin have been used to localize these proteins at the ultrastructural level: secondary cultures of 14-d-old chicken embryo lung epithelial cells and chicken heart fibroblasts were briefly lysed with either a 0.5% Triton X-100/0.25% glutaraldehyde mixture, or 0.1% Triton X-100, fixed with 0.5% glutaraldehyde, and further permeabilized with 0.5% Triton X-100, to allow penetration of the gold-conjugated antibodies. After immunogold staining (De Mey, J., M. Moeremans, G. Geuens, R. Nuydens, and M. De Brabander, 1981, Cell Biol. Int. Rep. 5:889-899), the cells were postfixed in glutaraldehyde-tannic acid and further processed for embedding and thin sectioning. This approach enabled us to document the distribution of alpha-actinin and filamin either on the delicate cortical networks of the cell periphery or in the densely bundled stress fibers and polygonal nets. By using antiactin immunogold staining as a control, we were able to demonstrate the applicability of the method to the microfilament system: the label was distributed homogeneously over all areas containing recognizable microfilaments, except within very thick stress fibers, where the marker did not penetrate completely. Although alpha-actinin specific staining was homogeneously localized along loosely-organized microfilaments, it was concentrated in the dense bodies of stress fibers. The antifilamin-specific staining showed a typically spotty or patchy pattern associated with the fine cortical networks and stress fibers. This pattern occurred along all actin filaments, including the dense bodies also marked by anti-alpha-actinin antibodies. The results confirm and extend the data from light microscopic investigations and provide more information on the structural basis of the microfilament system.

scholarly journals Cell Penetration and Trafficking of Polyomavirus

2003 ◽  
Vol 77 (4) ◽  
pp. 2615-2622 ◽  
Author(s):  
Joanna M. Gilbert ◽  
Ilya G. Goldberg ◽  
Thomas L. Benjamin
Keyword(s):  
Actin Filaments ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Endocytic Pathway ◽  
Dynamic State ◽  
Cell Penetration ◽  
Stabilizing Agents ◽  
Virus Particles ◽  
Murine Polyomavirus ◽  
Microfilament System

ABSTRACT The murine polyomavirus (Py) enters mouse fibroblasts and kidney epithelial cells via an endocytic pathway that is caveola-independent (as well as clathrin-independent). In contrast, uptake of simian virus 40 into the same cells is dependent on caveola. Following the initial uptake of Py, both microtubules and microfilaments play roles in trafficking of the virus to the nucleus. Colcemid, which disrupts microtubules, inhibits the ability of Py to reach the nucleus and replicate. Paclitaxel, which stabilizes microtubules and prevents microtubule turnover, has no effect, indicating that intact but not dynamic microtubules are required for Py infectivity. Compounds that disrupt actin filaments enhance Py uptake while stabilization of actin filaments impedes Py infection. Virus particles are seen in association with actin in cells treated with microfilament-disrupting or filament-stabilizing agents at levels comparable to those in untreated cells, suggesting that a dynamic state of the microfilament system is important for Py infectivity.

Role of microtubules in surfactant secretion

1985 ◽  
Vol 58 (6) ◽  
pp. 1866-1873 ◽  
Author(s):  
L. A. Brown ◽  
S. M. Pasquale ◽  
W. J. Longmore
Keyword(s):  
Secondary Response ◽  
Tubulin Polymerization ◽  
Type Ii Cells ◽  
Type Ii ◽  
Rat Lung ◽  
Beta Adrenergic ◽  
Camp Content ◽  
Adrenergic Agents ◽  
Surfactant Secretion ◽  
Microfilament System

In the isolated perfused rat lung and cultured type II cells, surfactant secretion and cellular adenosine 3′,5′-cyclic monophosphate (cAMP) content was stimulated by beta-adrenergic agonists. Isoproterenol-induced surfactant secretion was inhibited by the antimicrotubule agents colchicine and vinblastine. Incorporation of [3H]glycerol into disaturated phosphatidylcholine was augmented by beta-adrenergic agents but was not significantly different from the enhanced incorporation rate when colchicine was present. This suggests that the augmented incorporation of [3H]glycerol into disaturated phosphatidylcholine was a secondary response to storage depletion rather than direct cAMP stimulation. beta-Adrenergic agents shifted the equilibrium in the isolated perfused rat lung and cultured type II cells to favor microtubules. The stimulatory effect of 1.0 microM isoproterenol on tubulin polymerization was observed as early as 1 min and was augmented 2.8-fold at a half-maximal stimulation of 4 nM in cultured type II cells. Cytochalasin B, an antimicrofilament agent, potentiated the isoproterenol-induced secretion. These results suggest that an intact microtubule-microfilament system may be obligatory for enhanced surfactant secretion and that beta-adrenergic agents not only induce surfactant release but also tubulin polymerization.

scholarly journals Human erythroleukemia cells adhere to fibronectin: evidence for a Mr 190,000-receptor protein

Blood ◽  
1987 ◽  
Vol 69 (2) ◽  
pp. 578-583 ◽  
Author(s):  
I Virtanen ◽  
J Ylanne ◽  
T Vartio
Keyword(s):  
Cytochalasin B ◽  
K562 Cells ◽  
Active Role ◽  
Receptor Protein ◽  
Membrane Glycoproteins ◽  
Spreading Process ◽  
Erythroleukemia Cells ◽  
Microfilament System ◽  
Serum Free Conditions ◽  
Overlay Assay

Abstract Human erythroleukemia cells (K562) adhered rapidly on fibronectin (Fn)- coated growth substratum under serum-free conditions. The adhesion could be quantitatively inhibited by the synthetic peptide Arg-Gly-Asp- Ser (RGDS) and upon hemin-induced differentiation or trypsinization of the cells. Many of the cells also displayed rapid spreading that led to a redistribution of F-actin into spreading edges and in many cells also to a formation of typical actin fibers attaching to the ventral aspect of the cells. The spreading of the cells was inhibited by cytochalasin B but not by microtubule-disrupting drugs, suggesting an active role for the microfilament system in the spreading process. Direct overlay assay of electrophoretically separated polypeptides with 125I-Fn showed that in K562 cells there is a major Mr 190,000 Fn-binding protein that is lost upon differentiation. A similar overlay assay with purified plasma and cellular Fns followed by immunostaining with anti-Fn antibodies revealed a reaction with a similar polypeptide. The binding of Fns on the nitrocellulose sheets could be inhibited and the bound Fn eluted by using the RGDS peptide. From octylglucoside extracts of radioactively surface-labeled cells, distinct Mr 190,000/185,000 membrane glycoproteins bound to Fn-heptapeptide-Sepharose, further suggesting that the Mr 190,000 polypeptide would be the Fn-receptor of the K562 cells.

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