| Popis: |
In human foreskin fibroblast cultures, two proteins with Mr 60,000 and 55,000 were found to be induced about 3.5-fold by epidermal growth factor (EGF), platelet-derived growth factor, and beta-transforming growth factor. The induced proteins were identified as procollagenases by immunoprecipitation of induced medium with antibodies to purified human fibroblast collagenase. Collagenase enzyme activity in the medium from EGF-treated cultures was also induced at least 3-fold compared to control cultures. Induction of collagenase was dependent upon de novo protein and RNA synthesis and was observed in the medium 10 h after addition of EGF. Although these growth-promoting factors interact with separate membrane receptors, each induced the secretion of a common protein, suggesting that collagenase may be important in some aspect of mitogenesis, cell mobilization, and migration. |
