Regulation of surface expression of high-affinity receptors for epidermal growth factor (EGF) in hepatocytes by hormones, differentiating agents, and phorbol ester

1992 ◽  
Vol 37 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Ivar P. Gladhaug ◽  
Magne Refsnes ◽  
Thoralf Christoffersen
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Phorbol Ester ◽  
Surface Expression ◽  
High Affinity ◽  
Differentiating Agents ◽  
Epidermal Growth

scholarly journals Transforming growth factor-beta modulates the high-affinity receptors for epidermal growth factor and transforming growth factor-alpha.

1985 ◽  
Vol 100 (5) ◽  
pp. 1508-1514 ◽  
Author(s):  
J Massagué
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Affinity Labeling ◽  
Tgf Beta ◽  
Semisolid Medium ◽  
High Affinity ◽  
Receptor Structure ◽  
Epidermal Growth

The epidermal growth factor (EGF) receptor mediates the induction of a transformed phenotype in normal rat kidney (NRK) cells by transforming growth factors (TGFs). The ability of EGF and its analogue TGF-alpha to induce the transformed phenotype in NRK cells is greatly potentiated by TGF-beta, a polypeptide that does not interact directly with binding sites for EGF or TGF-alpha. Our evidence indicates that TGF-beta purified from retrovirally transformed rat embryo cells and human platelets induces a rapid (t 1/2 = 0.3 h) decrease in the binding of EGF and TGF-alpha to high-affinity cell surface receptors in NRK cells. No change due to TGF-beta was observed in the binding of EGF or TGF-alpha to lower affinity sites also present in NRK cells. The effect of TGF-beta on EGF/TGF-alpha receptors was observed at concentrations (0.5-20 pM) similar to those at which TGF-beta is active in promoting proliferation of NRK cells in monolayer culture and semisolid medium. Affinity labeling of NRK cells and membranes by cross-linking with receptor-bound 125I-TGF-alpha and 125I-EGF indicated that both factors interact with a common 170-kD receptor structure. Treatment of cells with TGF-beta decreased the intensity of affinity-labeling of this receptor structure. These data suggest that the 170 kD high-affinity receptors for EGF and TGF-alpha in NRK cells are a target for rapid modulation by TGF-beta.

Interaction of epidermal growth factor with receptors on human and porcine thyroid membranes

1984 ◽  
Vol 102 (1) ◽  
pp. 57-61 ◽  
Author(s):  
H. Humphries ◽  
S. MacNeil ◽  
D. S. Munro ◽  
S. Tomlinson
Keyword(s):  
Enzyme Activity ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Binding Sites ◽  
Affinity Constant ◽  
Maximal Inhibition ◽  
High Affinity ◽  
Epidermal Growth ◽  
And Function ◽  
Bovine Tsh

ABSTRACT Recent evidence suggests that epidermal growth factor (EGF) may play an important role in the regulation of thyroid growth and function. We have examined the interaction of murine EGF (mEGF) with human and porcine thyroid membranes and compared this with the binding of bovine TSH (bTSH) using 125I-labelled hormones as tracers. The characteristics of the binding of mEGF were found to be similar for human and porcine thyroid membranes. Epidermal growth factor bound with high affinity (affinity constant = 1·4 × 109 l/mol); the density of binding sites was low compared with the TSH receptor. At 37 °C, the binding of 125I-labelled EGF was maximal at 1 h and was saturable in the presence of unlabelled EGF; half-maximal inhibition was at 1 ng EGF/tube (0·5 nmol/l) using 0·5 mg membrane protein/tube. Unlabelled bTSH had no effect on the binding of labelled EGF. Similarly, unlabelled EGF did not affect the binding of labelled TSH; hence it was concluded that mEGF and bTSH bound to independent sites. Epidermal growth factor had no effect on adenylate cyclase activity in membranes prepared from human non-toxic goitre; increasing concentrations of EGF did not affect basal, TSH-stimulated or fluoride-stimulated enzyme activity. J. Endocr. (1984) 102, 57–61

scholarly journals Functional activity of epidermal growth factor receptors in autosomal recessive polycystic kidney disease

1998 ◽  
Vol 275 (3) ◽  
pp. F387-F394 ◽  
Author(s):  
William E. Sweeney ◽  
Ellis D. Avner
Keyword(s):  
Growth Factor ◽  
Kidney Disease ◽  
Epidermal Growth Factor ◽  
Polycystic Kidney Disease ◽  
Autosomal Recessive ◽  
Apical Surface ◽  
Polycystic Kidney ◽  
High Affinity ◽  
Epidermal Growth

Evidence from a number of laboratories suggests a potential role for the epidermal growth factor (EGF)-transforming growth factor-α-epidermal growth factor receptor (EGF-R) axis in promoting epithelial hyperplasia and cyst formation in autosomal recessive polycystic kidney disease (ARPKD). As previously reported, in the C57BL-6Jcpk/cpk (CPK), BALB/c-bpk/bpk (BPK), and C3H-orpk/orpk (ORPK) murine models of ARPKD, as well as in human ARPKD and human ADPKD, the EGF-R is mislocated to the apical surface of cystic collecting tubule (CT) epithelial cells. The present studies demonstrate that cells from cystic and control CTs can be isolated and that these cells maintain their in vivo EGF-R phenotype in vitro. Domain-specific high-affinity ligand binding was assessed by standard Scatchard analysis, and selective ligand stimulation of apical vs. basolateral EGF-R in these cells was followed by measurement of receptor autophosphorylation and determination of cell proliferation. These studies demonstrate that in vitro apically expressed EGF-Rs exhibit high-affinity binding for EGF, autophosphorylate in response to EGF, and transmit a mitogenic signal when stimulated by the appropriate ligand.

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