摘要:

AbstractExtracts of serum‐free conditioned medium from human rhabdomyosarcoma A673 cells contain high molecular weight (HMW) transforming growth factors (TGFs) that can be partially purified by Bio‐Gel P‐100 and carboxymethyl (CM)‐cellulose chromatography (Todaro et al: Proc Natl Acad Sci USA 77:5258, 1980). Reversephase high performance liquid chromatography (HPLC) revealed a principal peak of epidermal growth factor (EGF) radioreceptor assay (RRA) activity and anchorage‐independent growth (AIG) activity that coeluted with 25–26% acetonitrile. If a trailing shoulder of EGF RRA activity from the CM‐C chromatography was included in the material for HPLC analysis, additional active fractions were observed at 21–22% acetonitrile. Importantly, both active regions from HPLC failed to compete in radioimmunoassays under reduced and denatured conditions for human EGF (hEGF), human TGF‐α‐ (hTGF‐α), or rat TGF‐α (rTGF‐α) and failed to give positive signals in Western blots under conditions in which TGF‐α was readily detected when using an antisera raised against the 17 C‐terminal amino acids of rTGF‐α. Nonreducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) revealed EGF RRA and AIG activities in gel slices corresponding to Mr15,000 and 22,000 in the 25–26% acetonitrile eluate and Mr 15,000, 20,000, 27,000, and 48,000 in the 21–22% acetonitrile eluate. The presence of multiple forms of EGF‐receptor‐binding peptides produced in vitro suggest size heterogeneity and possible immunologic diversity among high molecular weight members of the EG

ISSN:0730-2312    

DOI:10.1002/jcb.240320402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractIt has been recognized for many years that α‐thrombin, like other better known mitogens (eg, PDGF, EOF, etc) is capable of initiating proliferation in quiescent cells belonging to the fibroblast family. However, unlike these other peptides, thrombin is a serine protease whose function as a growth stimulator for fibroblasts is intimately linked to its estefolytic activity. Thus, while native α‐thrombin is capable of evoking DNA synthesis in GoG1‐arrested cells, neither enzymatically inactive thrombin (eg, iPR2P‐α‐thrombin) nor partially degraded thrombin (eg, γ‐thrombin) shares in this capability. Data from our laboratory have shown that thrombin is chemotactic for peripheral blood monocytes and for cells belonging to the monocyte/macrophage family and that this activity is not dependent upon thrombin's enzymatic properties. Our recent findings demonstrate that thrombin also serves as a growth factor for these cells, and this mitogenic capability is independent of esterolytic function and resides in the same region of the molecule as that responsible for chemotaxis. Additionally, by means of techniques such as computer modeling and peptide synthesis, we have now been able to delineate a distinct mitogenic subsite within this chemotactic thrombin sequence. Thus, the sequence in the thrombin B chain that mediates chemotaxis represents a true cell interactive exosite additionally capable of stimulating growth and possibly other biological functions in cells of macrophage/m

ISSN:0730-2312    

DOI:10.1002/jcb.240320403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractCultured bovine aortic endothelial cells have a relatively complex flbrinolytic system that is responsive to both the physiological state of the cell itself and to a variety of agents added to the culture medium. The flbrinolytic activity of these cells results from the production of both urokinase‐type and tissue‐type plasminogen activators and is regulated by an inhibitor capable of neutralizing their activities. The properties of these flbrinolytic components will be reviewed, and their respective roles in initiating and regulating the flbrinolytic activity of the cells will be summarized. A cDNA coding for the inhibitor has been isolated, and its sequence will be compared to that of other serine proteinase inhibit

ISSN:0730-2312    

DOI:10.1002/jcb.240320404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThis review summarizes the mechanisms by which several serine proteases, particularly urokinase, thrombin, and elastase, interact with cultured fibroblasts. Many of these studies were prompted by findings that interactions of these proteases with cells and the extracellular matrix are important in a number of physiologic and pathologic processes. Two main pathways have been identified for specific interactions of these proteases with fibroblasts. One involves surface binding sites for the free protease that appear to bind only one particular protease. An unusual feature collectively shared by the binding sites for urokinase, thrombin, and elastase is that the bound protease is not detectably internalized by the fibroblasts. The other pathway by which serine proteases interact with fibroblasts involves proteins named protease nexins (PNs). Three PNs have been identified. They are secreted by fibroblasts and inhibit certain serine proteases by forming a covalent complex with the protease catalytic site serine. The complexes then bind back to the fibroblasts via the PN portion of the complex and are internalized and degraded. Recent studies showing that the fibroblast surface and extracellular matrix accelerate the inactivation of thrombin by PN‐1 support the hypothesis that the PNs control protease activity at and near the cell surface. The PNs differ from plasma protease inhibitors in their molecular properties, absence in plasma, site of synthesis, and site of clearance of the inhibitor:protease complexe

ISSN:0730-2312    

DOI:10.1002/jcb.240320405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0730-2312    

DOI:10.1002/jcb.240320406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0730-2312    

DOI:10.1002/jcb.240320407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0730-2312    

DOI:10.1002/jcb.240320401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY