scholarly journals Fibronectin-independent adhesion of fibroblasts to the extracellular matrix: mediation by a high molecular weight membrane glycoprotein.

1981 ◽  
Vol 91 (3) ◽  
pp. 647-653 ◽  
Author(s):  
P A Harper ◽  
R L Juliano
Keyword(s):  
Molecular Weight ◽  
Extracellular Matrix ◽  
High Molecular Weight ◽  
Cho Cells ◽  
Matrix Material ◽  
Differential Sensitivity ◽  
Galactose Oxidase ◽  
Membrane Glycoprotein ◽  
Type I ◽  
Type Ii

Fibroblastic CHO cells readily adhere to fibronectin (Fn) coated substrata. From the parental cell population we have recently selected a series of adhesion variants (ADV cells) that cannot adhere to Fn substrata (Harper and Juliano. 1980. J. Cell. Biol. 87:755-763). However, ADV cells readily adhere to substrata coated with extracellular matrix material (ECM) derived from human diploid fibroblasts by a mechanism that does not involve fibronectin (Harper and Juliano. 1981. Nature (Lond.). 290:136-138). Te Fn-dependent adhesion mechanism of parental cells (type 1 adhesion) and the ECM-dependent adhesion of ADV cells (type II adhesion) can also be discriminated on the basis of their differential sensitivity to proteolysis, with the type II mechanism being far more sensitive. In this communication we report that parental CHO cells possess both type I and type II mechanisms whereas ADV cells possess only the type II mechanism. We also identify a high molecular weight membrane glycoprotein (gp 265) that seems to play a role in type II adhesion. This component is detected by [125I]lactoperoxidase of [3H]borohydride-galactose oxidase labeling of surface proteins in WT and AD cells. Cleavage of gp 265 with low doses of proteases correlates completely with the loss of type II adhesion capacity. Thus CHO cells possess two functionally and biochemically distinct adhesion mechanisms, one involving exogenous Fn and the other mediated by the membrane component gp 265.

scholarly journals The Type II Deiodinase Is Retrotranslocated to the Cytoplasm and Proteasomes via p97/Atx3 Complex

2013 ◽  
Vol 27 (12) ◽  
pp. 2105-2115 ◽  
Author(s):  
Rafael Arrojo e Drigo ◽  
Péter Egri ◽  
Sungro Jo ◽  
Balázs Gereben ◽  
Antonio C. Bianco
Keyword(s):  
Molecular Weight ◽  
Endoplasmic Reticulum ◽  
Thyroid Hormone ◽  
High Molecular Weight ◽  
20S Proteasome ◽  
Type I ◽  
Type Ii ◽  
Cell Models ◽  
Natural Substrate ◽  
Iodothyronine Deiodinase

The type II iodothyronine deiodinase (D2) is a type I endoplasmic reticulum (ER)-resident thioredoxin fold-containing selenoprotein that activates thyroid hormone. D2 is inactivated by ER-associated ubiquitination and can be reactivated by two ubiquitin-specific peptidase-class D2-interacting deubiquitinases (DUBs). Here, we used D2-expressing cell models to define that D2 ubiquitination (UbD2) occurs via K48-linked ubiquitin chains and that exposure to its natural substrate, T4, accelerates UbD2 formation and retrotranslocation to the cytoplasm via interaction with the p97-ATPase complex. D2 retrotranslocation also includes deubiquitination by the p97-associated DUB Ataxin-3 (Atx3). Inhibiting Atx3 with eeyarestatin-I did not affect D2:p97 binding but decreased UbD2 retrotranslocation and caused ER accumulation of high-molecular weight UbD2 bands possibly by interfering with the D2-ubiquitin-specific peptidases binding. Once in the cytosol, D2 is delivered to the proteasomes as evidenced by coprecipitation with 19S proteasome subunit S5a and increased colocalization with the 20S proteasome. We conclude that interaction between UbD2 and p97/Atx3 mediates retranslocation of UbD2 to the cytoplasm for terminal degradation in the proteasomes, a pathway that is accelerated by exposure to T4.

Carbon Fibre Reinforced Ultra-High Molecular Weight Polyethylene for Medical Application

1977 ◽  
Vol 6 (4) ◽  
pp. 123-124 ◽  
Author(s):  
J S Bradley ◽  
E J Evans
Keyword(s):  
Molecular Weight ◽  
Composite Material ◽  
High Molecular Weight ◽  
Medical Application ◽  
Flexural Properties ◽  
Type I ◽  
Type Ii ◽  
Carbon Fibres ◽  
Compression Moulding ◽  
Ultra High Molecular Weight

Ultra-high molecular weight polyethylene (UHMWPE) has been reinforced with type I and type II carbon fibres by a compression moulding technique. The composite is found to have markedly improved tensile and flexural properties, suggesting that it would be useful both as an improvement to current polyethylene components and as an inducement to more elaborate designs using the composite material.

Fibronectin-independent adhesion of fibroblasts to extracellular matrix material: partial characterization of the matrix components

1983 ◽  
Vol 63 (1) ◽  
pp. 287-301
Author(s):  
P.A. Harper ◽  
P. Brown ◽  
R.L. Juliano
Keyword(s):  
Extracellular Matrix ◽  
Matrix Material ◽  
Block Type ◽  
Type I ◽  
Type Ii ◽  
Matrix Component ◽  
Tyrosine Residues ◽  
The Matrix ◽  
Dependent Type

Fibroblasts can adhere to extracellular matrix (ECM) material by fibronectin-dependent (type I) and fibronectin-independent (type II) mechanisms. In this report we investigate the biochemical characteristics of ECM that contribute to type II adhesion. ECM capable of mediating type II adhesions is produced primarily by normal diploid fibroblasts, but not by transformed cells or epithelial cells. Treatment of fibroblast ECM under conditions that result in the removal of most of the ECM lipid or most of the ECM glycosaminoglycan does not impair type II adhesion. Likewise, treatment of the ECM with large amounts of purified collagenase does not block type II adhesion. However, treatment of ECM with low doses of trypsin or with an agent that reacts with tyrosine residues, results in complete ablation of the ability of the ECM to support type II adhesion. On the basis of these observations we suggest that the matrix component(s) mediating type II adhesion are non-collagenous proteins or glycoproteins.

Molecular characterization of an inward rectifier channel (IKir) found in avian vestibular hair cells: cloning and expression of pKir2.1

2004 ◽  
Vol 19 (2) ◽  
pp. 155-169 ◽  
Author(s):  
Manning J. Correia ◽  
Thomas G. Wood ◽  
Deborah Prusak ◽  
Tianxiang Weng ◽  
Katherine J. Rennie ◽  
...  
Keyword(s):  
Hair Cells ◽  
Cho Cells ◽  
Dwell Time ◽  
Single Channel ◽  
Cloning And Expression ◽  
Single Type ◽  
Type I ◽  
Type Ii ◽  
Vestibular Hair Cells ◽  
Inwardly Rectifying

A fast inwardly rectifying current has been observed in some of the sensory cells (hair cells) of the inner ear of several species. While the current was presumed to be an IKir current, contradictory evidence existed as to whether the cloned channel actually belonged to the Kir2.0 subfamily of potassium inward rectifiers. In this paper, we report for the first time converging evidence from electrophysiological, biochemical, immunohistochemical, and genetic studies that show that the Kir2.1 channel carries the fast inwardly rectifying currents found in pigeon vestibular hair cells. Following cytoplasm extraction from single type II and multiple pigeon vestibular hair cells, mRNA was reverse transcribed, amplified, and sequenced. The open reading frame (ORF), consisting of a 1,284-bp nucleotide sequence, showed 94, 85, and 83% identity with Kir2.1 subunit sequences from chick lens, Kir2 sequences from human heart, and a mouse macrophage cell line, respectively. Phylogenetic analyses revealed that pKir2.1 formed an immediate node with hKir2.1 but not with hKir2.2–2.4. Hair cells (type I and type II) and supporting cells in the sensory epithelium reacted positively with a Kir2.1 antibody. The whole cell current recorded in oocytes and CHO cells, transfected with pigeon hair cell Kir2.1 (pKir2.1), demonstrated blockage by Ba2+ and sensitivity to changing K+ concentration. The mean single-channel linear slope conductance in transfected CHO cells was 29 pS. The open dwell time was long (∼300 ms at −100 mV), and the closed dwell time was short (∼34 ms at −100 mV). Multistates ranging from 3–6 were noted in some single-channel responses. All of the above features have been described for other Kir2.1 channels. Current clamp studies of native pigeon vestibular hair cells illustrated possible physiological roles of the channel and showed that blockage of the channel by Ba2+ depolarized the resting membrane potential by ∼30 mV. Negative currents hyperpolarized the membrane ∼20 mV before block but ∼60 mV following block. RT-PCR studies revealed that the pKir2.1 channels found in pigeon vestibular hair cells were also present in pigeon vestibular nerve, vestibular ganglion, lens, neck muscle, brain (brain stem, cerebellum and optic tectum), liver, and heart.

Effect of tunicamycin on maturation of fetal mouse lung

1993 ◽  
Vol 265 (3) ◽  
pp. L250-L259
Author(s):  
E. H. Webster ◽  
S. R. Hilfer ◽  
R. L. Searls ◽  
J. Kornilow
Keyword(s):  
Extracellular Matrix ◽  
Fetal Lung ◽  
Mouse Lung ◽  
Type I ◽  
Type Ii ◽  
Fetal Mouse ◽  
Type Ii Pneumocytes ◽  
Separate Control ◽  
Normal Controls

The mesodermal capsule of the fetal lung plays a role in differentiation of the respiratory region. It has been proposed for other epithelial organs that the mesodermal capsule influences development by modifying the basal lamina or the extended extracellular matrix. The effect could be on deposition or turnover of collagens, proteoglycans, and/or glycoproteins. This study tests the role of glycoproteins in differentiation of respiratory endings by inhibiting their synthesis with the antibiotic tunicamycin (TM). Lungs at 16 and 18 days gestation and 3 days after birth were cultured with TM and examined for morphological and biochemical differences from normal controls. With TM, alveolar regions did not expand properly and formed fewer type I pneumocytes, although type II pneumocytes were unaffected. The epithelium of untreated respiratory regions showed greater incorporation of radioactive mannose than the airways region or mesenchyme. This incorporation was diminished in TM, but the pattern persisted. Comparison with the results obtained with beta-xyloside suggested that differentiation of type I and type II pneumocytes is under separate control.

Alveolar type II cell growth on a pulmonary endothelial extracellular matrix

1996 ◽  
Vol 270 (6) ◽  
pp. L1017-L1022 ◽  
Author(s):  
I. Y. Adamson ◽  
L. Young
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Cell Growth ◽  
Alveolar Type ◽  
Thymidine Uptake ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Type Ii Cell

Most of the alveolar epithelium overlies a fused basement membrane produced by epithelial and endothelial cells. To determine how this type of matrix influences type II cell growth and function, we studied the effects of culturing isolated rat alveolar type II cells on an extracellular matrix (ECM) freshly produced by pulmonary vascular endothelial cells grown 5 days in culture. Type II cells from the same rats were cultured on plastic or Matrigel for comparison. A large increase in mitotic activity was seen in type II cells grown on the endothelial ECM at 2 days only; thereafter cells spread rapidly to confluence and lost their lamellar bodies. Cells grown on Matrigel remained cuboidal with lamellar bodies but grew more slowly, as judged by [3H]thymidine uptake and cell numbers. Incorporation of labeled choline into disaturated phosphatidylcholine (DSPC) was used as a marker of surfactant synthesis. After the rapid, brief burst of proliferation, type II cells on endothelial ECM showed a sudden decline in DSPC-DNA by day 4 compared with cells grown on matrigel. Binding of the lectin Bauhinia purpurea (BPA) indicated that after a phase of division, cells on endothelial ECM developed as type I epithelium by 4 days of culture, when > 70% of cells stained positively for BPA binding, whereas few cuboidal cells on Matrigel were stained. The results indicate that type II cells respond briefly to growth factors in pulmonary endothelial ECM; then this type of matrix promotes cell spreading with loss of type II function as cells subsequently resemble type I epithelium.

scholarly journals Integrin β1Signaling Is Necessary for Transforming Growth Factor-β Activation of p38MAPK and Epithelial Plasticity

2001 ◽  
Vol 276 (50) ◽  
pp. 46707-46713 ◽  
Author(s):  
Neil A. Bhowmick ◽  
Roy Zent ◽  
Mayshan Ghiassi ◽  
Maureen McDonnell ◽  
Harold L. Moses
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Transcriptional Activation ◽  
Intracellular Signaling ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Dominant Negative ◽  
Receptor Expression ◽  
Type I ◽  
Type Ii

Transforming growth factor-β (TGF-β) can induce epithelial to mesenchymal transdifferentiation (EMT) in mammary epithelial cells. TGF-β-meditated EMT involves the stimulation of a number of signaling pathways by the sequential binding of the type II and type I serine/threonine kinase receptors, respectively. Integrins comprise a family of heterodimeric extracellular matrix receptors that mediate cell adhesion and intracellular signaling, hence making them crucial for EMT progression. In light of substantial evidence indicating TGF-β regulation of various β1integrins and their extracellular matrix ligands, we examined the cross-talk between the TGF-β and integrin signal transduction pathways. Using an inducible system for the expression of a cytoplasmically truncated dominant negative TGF-β type II receptor, we blocked TGF-β-mediated growth inhibition, transcriptional activation, and EMT progression. Dominant negative TGF-β type II receptor expression inhibited TGF-β signaling to the SMAD and AKT pathways, but did not block TGF-β-mediated p38MAPK activation. Interestingly, blocking integrin β1function inhibited TGF-β-mediated p38MAPK activation and EMT progression. Limiting p38MAPK activity through the expression of a dominant negative-p38MAPK also blocked TGF-β-mediated EMT. In summary, TGF-β-mediated p38MAPK activation is dependent on functional integrin β1, and p38MAPK activity is required but is not sufficient to induce EMT.

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