Stimulation by transforming growth factor-β of epidermal growth factor-dependent growth of aged human fibroblasts: Recovery of high affinity EGF receptors and growth stimulation by EGF

1989 ◽  
Vol 25 (10) ◽  
pp. 965-970 ◽  
Author(s):  
Tomoyuki Kawamoto ◽  
Mieko Nishi ◽  
Kojiro Takahashi ◽  
Toshio Nishiyama ◽  
J. Denry Sato ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Transforming Growth Factor ◽  
Human Fibroblasts ◽  
Transforming Growth Factor Β ◽  
Growth Stimulation ◽  
Egf Receptors ◽  
High Affinity ◽  
Epidermal Growth ◽  
Dependent 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.

Segmental distribution of epidermal growth factor binding sites in rabbit nephron

1990 ◽  
Vol 259 (4) ◽  
pp. F553-F558 ◽  
Author(s):  
M. D. Breyer ◽  
R. Redha ◽  
J. A. Breyer
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Transforming Growth Factor ◽  
Specific Binding ◽  
Rabbit Kidney ◽  
Egf Receptors ◽  
Collecting Ducts ◽  
Epidermal Growth ◽  
Sites Of Action ◽  
Convoluted Tubules

The kidney possesses epidermal growth factor (EGF) receptors and is a major site of synthesis for the EGF precursor, prepro-EGF. To examine the segmental localization of EGF receptors in the rabbit kidney, we characterized 125I-labeled EGF binding to micro-dissected rabbit nephron segments. Specific binding constituted 70-80% of total binding and was saturable with an apparent Kd of 8 nM. Kinetic studies (0 degrees C) revealed an association t1/2 of 20.7 min and a dissociation t1/2 of 27 min. Competition studies revealed that 125I-EGF binding was inhibited by unlabeled EGF or its homologue transforming growth factor-alpha, but not by parathyroid hormone or insulin. Mapping studies showed specific 125I-EGF binding (attomoles per centimeter) was highest in proximal straight tubules, followed by proximal convoluted tubules, cortical collecting ducts, inner medullary collecting ducts, outer medullary collecting ducts, and distal convoluted tubules. Specific binding to glomeruli was also observed. Interestingly, no specific binding of 125I-EGF to thick ascending limbs, a site of EGF precursor synthesis, was observed. These studies suggest potential sites of action for EGF in the rabbit kidney.

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