scholarly journals Tumor promoter and epidermal growth factor stimulate phosphorylation of the c-erbB-2 gene product in MKN-7 human adenocarcinoma cells.

1988 ◽  
Vol 8 (3) ◽  
pp. 1019-1026 ◽  
Author(s):  
T Akiyama ◽  
T Saito ◽  
H Ogawara ◽  
K Toyoshima ◽  
T Yamamoto
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Gene Product ◽  
Egf Receptor ◽  
Binding Activity ◽  
Tumor Promoter ◽  
Adenocarcinoma Cells ◽  
Epidermal Growth ◽  
Phosphopeptide Mapping

Treatment of human adenocarcinoma MKN-7 cells with epidermal growth factor (EGF) or phorbol tetradecanoate acetate (TPA) stimulated phosphorylation of the c-erbB-2 gene product. EGF induced a rapid increase in phosphotyrosine followed by relatively gradual increases in phosphoserine and phosphothreonine. On the other hand, the TPA-induced increase in phosphorylations occurred exclusively on serine and threonine residues. Tryptic phosphopeptide mapping analysis suggested that treatments with EGF and TPA induced phosphorylation of many common sites in the c-erbB-2 gene product. However, in contrast to TPA, EGF increased the phosphorylation of the c-erbB-2 protein in cells whose protein kinase C had been down-regulated by long-term pretreatment with TPA, suggesting that EGF and TPA induce phosphorylation by different mechanisms. Since the c-erbB-2 gene product did not show detectable EGF-binding activity, phosphorylation of tyrosine of the c-erbB-2 gene product might be catalyzed directly by the EGF receptor kinase that was activated by EGF.

Tumor promoter and epidermal growth factor stimulate phosphorylation of the c-erbB-2 gene product in MKN-7 human adenocarcinoma cells

1988 ◽  
Vol 8 (3) ◽  
pp. 1019-1026
Author(s):  
T Akiyama ◽  
T Saito ◽  
H Ogawara ◽  
K Toyoshima ◽  
T Yamamoto
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Gene Product ◽  
Egf Receptor ◽  
Binding Activity ◽  
Tumor Promoter ◽  
Adenocarcinoma Cells ◽  
Epidermal Growth ◽  
Phosphopeptide Mapping

Treatment of human adenocarcinoma MKN-7 cells with epidermal growth factor (EGF) or phorbol tetradecanoate acetate (TPA) stimulated phosphorylation of the c-erbB-2 gene product. EGF induced a rapid increase in phosphotyrosine followed by relatively gradual increases in phosphoserine and phosphothreonine. On the other hand, the TPA-induced increase in phosphorylations occurred exclusively on serine and threonine residues. Tryptic phosphopeptide mapping analysis suggested that treatments with EGF and TPA induced phosphorylation of many common sites in the c-erbB-2 gene product. However, in contrast to TPA, EGF increased the phosphorylation of the c-erbB-2 protein in cells whose protein kinase C had been down-regulated by long-term pretreatment with TPA, suggesting that EGF and TPA induce phosphorylation by different mechanisms. Since the c-erbB-2 gene product did not show detectable EGF-binding activity, phosphorylation of tyrosine of the c-erbB-2 gene product might be catalyzed directly by the EGF receptor kinase that was activated by EGF.

Effects of epidermal growth factor and 12-O-tetradecanoylphorbol-13-acetate on metabolism of the epidermal growth factor receptor in normal human fibroblasts

1984 ◽  
Vol 4 (9) ◽  
pp. 1718-1724
Author(s):  
S J Decker
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Half Life ◽  
Egf Receptor ◽  
Human Fibroblasts ◽  
Tumor Promoter ◽  
Minor Amount ◽  
Detectable Effect ◽  
Normal Human ◽  
Epidermal Growth

The biosynthesis, phosphorylation, and degradation of the epidermal growth factor (EGF) receptor were examined in normal human fibroblasts. The receptor was initially synthesized as an Mr = 160,000 immature form which matured to an Mr = 170,000 form in a monensin-sensitive manner. Tunicamycin treatment led to the accumulation of an Mr = 130,000 protein. The receptor was phosphorylated on serine and threonine residues in normally growing and quiescent cells, and treatment with EGF or the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in a two- to threefold increase in receptor-bound phosphate. EGF increased the amount of phosphoserine and phosphothreonine and caused the appearance of a minor amount of phosphotyrosine. TPA increased the levels of phosphoserine and phosphothreonine exclusively. Prior treatment with TPA inhibited the EGF-dependent appearance of phosphotyrosine in the receptor. Analysis of tryptic phosphopeptides revealed that six of the seven major peptides were common to the receptor from cells treated with EGF or TPA. EGF strongly stimulated [3H]thymidine incorporation in confluent cells, increased final saturation density three to fourfold, and increased whole-cell levels of phosphotyrosine about threefold. Treatment of cells with TPA before addition of EGF inhibited all three of these EGF-dependent responses. EGF also decreased the receptor half-life from 15 h to 1 h, but this was not inhibited by TPA. TPA alone had no detectable effect on the receptor half-life.

scholarly journals Effects of epidermal growth factor and 12-O-tetradecanoylphorbol-13-acetate on metabolism of the epidermal growth factor receptor in normal human fibroblasts.

1984 ◽  
Vol 4 (9) ◽  
pp. 1718-1724 ◽  
Author(s):  
S J Decker
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Half Life ◽  
Egf Receptor ◽  
Human Fibroblasts ◽  
Tumor Promoter ◽  
Minor Amount ◽  
Detectable Effect ◽  
Normal Human ◽  
Epidermal Growth

The biosynthesis, phosphorylation, and degradation of the epidermal growth factor (EGF) receptor were examined in normal human fibroblasts. The receptor was initially synthesized as an Mr = 160,000 immature form which matured to an Mr = 170,000 form in a monensin-sensitive manner. Tunicamycin treatment led to the accumulation of an Mr = 130,000 protein. The receptor was phosphorylated on serine and threonine residues in normally growing and quiescent cells, and treatment with EGF or the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in a two- to threefold increase in receptor-bound phosphate. EGF increased the amount of phosphoserine and phosphothreonine and caused the appearance of a minor amount of phosphotyrosine. TPA increased the levels of phosphoserine and phosphothreonine exclusively. Prior treatment with TPA inhibited the EGF-dependent appearance of phosphotyrosine in the receptor. Analysis of tryptic phosphopeptides revealed that six of the seven major peptides were common to the receptor from cells treated with EGF or TPA. EGF strongly stimulated [3H]thymidine incorporation in confluent cells, increased final saturation density three to fourfold, and increased whole-cell levels of phosphotyrosine about threefold. Treatment of cells with TPA before addition of EGF inhibited all three of these EGF-dependent responses. EGF also decreased the receptor half-life from 15 h to 1 h, but this was not inhibited by TPA. TPA alone had no detectable effect on the receptor half-life.

scholarly journals Long-term, heterologous down-regulation of the epidermal growth factor receptor in PC12 cells by nerve growth factor.

1987 ◽  
Vol 104 (6) ◽  
pp. 1611-1621 ◽  
Author(s):  
P Lazarovici ◽  
G Dickens ◽  
H Kuzuya ◽  
G Guroff
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Pc12 Cells ◽  
Egf Receptor ◽  
Down Regulation ◽  
Nerve Growth ◽  
Differentiated Cells ◽  
Epidermal Growth

Cells of the rat pheochromocytoma clone PC12 possess receptors for both nerve growth factor (NGF) and epidermal growth factor (EGF), thus enabling the study of the interaction of these receptors in the regulation of proliferation and differentiation. Treatment of the cells with NGF induces a progressive and nearly total decrease in the specific binding of EGF beginning after 12 h and completed within 4 d. Three different measures of receptor show that the decreased binding capacity represents, in fact, a decreased amount of receptor: (a) affinity labeling of PC12 cell membranes by cross-linking of receptor-bound 125I-EGF showed a 60-90% decrease in the labeling of 170- and 150-kD receptor bands in cells treated with NGF for 1-4 d; (b) EGF-dependent phosphorylation of a src-related synthetic peptide or EGF receptor autophosphorylation with membranes from NGF-differentiated cells showed a decrease of 80 and 90% in the tyrosine kinase activity for the exogenous substrate and for receptor autophosphorylation, respectively; (c) analysis of 35S-labeled glycoproteins isolated by wheat germ agglutinin-Sepharose chromatography from detergent extracts of PC12 membranes showed a 70-90% decrease in the 170-kD band in NGF-differentiated cells. These findings permit the hypothesis that long-term heterologous down-regulation of EGF receptors by NGF in PC12 cells is mediated by an alteration in EGF receptor synthesis. It is suggested that this heterologous down-regulation is part of the mechanism by which differentiating cells become insensitive to mitogens.

scholarly journals Phosphorylation of Tyrosine 992, 1068, and 1086 Is Required for Conformational Change of the Human Epidermal Growth Factor Receptor C-Terminal Tail

1999 ◽  
Vol 10 (3) ◽  
pp. 525-536 ◽  
Author(s):  
Anupam Bishayee ◽  
Laura Beguinot ◽  
Subal Bishayee
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Point Mutations ◽  
Growth Factor Receptor ◽  
Binding Activity ◽  
Tyrosine Residues ◽  
Amino Acid Peptide ◽  
C Terminus ◽  
Epidermal Growth

We reported previously that a conformation-specific antibody, Ab P2, to a 16-amino acid peptide (Glu-Gly-Tyr-Lys-Lys-Lys-Tyr-Gln-Gln-Val-Asp-Glu-Glu-Phe-Leu-Arg) of the cytoplasmic domain of the β-type platelet-derived growth factor receptor also recognizes the epidermal growth factor (EGF) receptor. Although the antibody is not directed to phosphotyrosine, it recognizes in immunoprecipitation the activated and hence phosphorylated form of both receptors. In P2 peptide, there are two tripeptide sequences, Asp-Glu-Glu and Tyr-Gln-Gln, that are also present in the EGF receptor. Our present studies using either EGF receptor C-terminal deletion mutants or point mutations (Tyr→Phe) and our previous studies on antibody inhibition by P2-derived peptides suggest that Gln-Gln in combination with Asp-Glu-Glu forms a high-affinity complex with Ab P2 and that such complex formation is dependent on tyrosine phosphorylation. Of the five phosphate acceptor sites in the EGF receptor, clustered in the extreme C-terminal tail, phosphorylation of three tyrosine residues (992, 1068, and 1086) located between Asp-Glu-Glu and Gln-Gln is necessary for Ab P2 binding. In contrast, the acceptor sites Tyr 1173 and 1148 play no role in the conformation change. Asp-Glu-Glu and Gln-Gln are located 169 amino acids apart, and it is highly likely that the interactions among three negatively charged phosphotyrosine residues in the receptor C terminus may result in the bending of the peptide chain in such a way that these two peptides come close to each other to form an antibody-binding site. Such a possibility is also supported by our finding that receptor dephosphorylation results in complete loss of Ab P2–binding activity. In conclusion, we have identified a domain within the cytoplasmic part of the EGF receptor whose conformation is altered by receptor phosphorylation; furthermore, we have identified the tyrosine residues that positively regulate this conformation.

947: Chemopreventive Effects of COX-2 Inhibitor and Epidermal Growth Factor (EGF)-Receptor Kinase Inhibitor on Rat Urinary Bladder Tumorigenesis

2004 ◽  
Vol 171 (4S) ◽  
pp. 251-251
Author(s):  
Kazunori Hattori ◽  
Katsuyuki Iida ◽  
Akira Johraku ◽  
Sadamu Tsukamoto ◽  
Taeko Asano ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Urinary Bladder ◽  
Egf Receptor ◽  
Kinase Inhibitor ◽  
Receptor Kinase ◽  
Rat Urinary Bladder ◽  
Epidermal Growth ◽  
Cox 2
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