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Expression of transformation-associated protease(s) that degrade fibronectin at cell contact sites.
| Content Provider | Scilit |
|---|---|
| Author | Chen, W. T. Olden, K. Bernard, B. A. Chu, F. F. |
| Copyright Year | 1984 |
| Abstract | Virus-transformed fibroblasts show an increased production of proteases as well as loss of extracellular adhesive proteins. To determine whether these transformation-associated events are related, we investigated the capacity of Rous sarcoma virus-transformed cells (embryonic chick fibroblasts and mouse BALB/c 3T3) to degrade fibronectin by using a novel cross-linked protein substratum: fluorescence-labeled or radiolabeled fibronectin covalently linked to the surface of a fixed gelatin film. In serum-containing medium, the coupled fibronectin was not released when incubated without cells, and only a small amount was released when incubated with nontransformed cells. However, when transformed cells were seeded on the radiolabeled fibronectin-coupled substratum, there was a threefold increase in the time-dependent release of radioactivity into the medium. The released material was characterized as peptides with molecular sizes of less than 30,000 daltons. Correspondingly, growth of transformed cells on the rhodamine-fibronectin substratum resulted in the appearance of discrete negative fluorescent spots beneath the cells and along their migratory paths, whereas a uniform fluorescent carpet was detected with nontransformed cells. The release of radioactivity was partially inhibited by protease inhibitors, including alpha 2-macroglobulin, leupeptin, and benzamidine, but the negative fluorescent spots appeared unaffected by any of these inhibitors. However, both the release of radiolabeled peptides and the appearance of fluorescence-negative spots were inhibited by 1,10-phenanthroline at concentrations that did not affect cellular attachment and protein synthesis, thus supporting a role for proteases in localized degradation of fibronectin substratum. These fluorescence-negative spots coincided with sites of fibronectin disappearance as judged by indirect labeling with antibodies to cellular fibronectin. In addition, immunofluorescent analyses showed a correlation between vinculin localization and the negative fibronectin spots found under transformed cells, indicating that degradation occurs at cell substratum contact sites. These results can be correlated with other transformation-associated phenotypic changes, and are discussed in terms of the invasion of tumor cells into the extracellular matrix. |
| Related Links | http://jcb.rupress.org/content/98/4/1546.full.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2113210/pdf |
| Ending Page | 1555 |
| Page Count | 10 |
| Starting Page | 1546 |
| DOI | 10.1083/jcb.98.4.1546 |
| Journal | Journal of Cell Biology |
| Issue Number | 4 |
| Volume Number | 98 |
| Language | English |
| Publisher | Rockefeller University Press |
| Publisher Date | 1984-04-01 |
| Access Restriction | Open |
| Subject Keyword | Biochemistry and Molecular Biology Protein Extracellular Protease Contact Sites Transformed Cells Fibronectin Substratum Degrade Fibronectin Journal: Journal of Cell Biology (Vol- 98, Issue- 4) |
| Content Type | Text |
