ErbB3 is involved in activation of phosphatidylinositol 3-kinase by epidermal growth factor

1994 ◽  
Vol 14 (6) ◽  
pp. 3550-3558
Author(s):  
S P Soltoff ◽  
K L Carraway ◽  
S A Prigent ◽  
W G Gullick ◽  
L C Cantley
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Kinase Activity ◽  
Egf Receptor ◽  
A549 Cells ◽  
Sh2 Domain ◽  
Recognition Sequence ◽  
A431 Cells ◽  
Erbb2 Protein ◽  
Epidermal Growth

Conflicting results concerning the ability of the epidermal growth factor (EGF) receptor to associate with and/or activate phosphatidylinositol (PtdIns) 3-kinase have been published. Despite the ability of EGF to stimulate the production of PtdIns 3-kinase products and to cause the appearance of PtdIns 3-kinase activity in antiphosphotyrosine immunoprecipitates in several cell lines, we did not detect EGF-stimulated PtdIns 3-kinase activity in anti-EGF receptor immunoprecipitates. This result is consistent with the lack of a phosphorylated Tyr-X-X-Met motif, the p85 Src homology 2 (SH2) domain recognition sequence, in this receptor sequence. The EGF receptor homolog, ErbB2 protein, also lacks this motif. However, the ErbB3 protein has seven repeats of the Tyr-X-X-Met motif in the carboxy-terminal unique domain. Here we show that in A431 cells, which express both the EGF receptor and ErbB3, PtdIns 3-kinase coprecipitates with the ErbB3 protein (p180erbB3) in response to EGF. p180erbB3 is also shown to be tyrosine phosphorylated in response to EGF. In contrast, a different mechanism for the activation of PtdIns 3-kinase in response to EGF occurs in certain cells (PC12 and A549 cells). Thus, we show for the first time that ErbB3 can mediate EGF responses in cells expressing both ErbB3 and the EGF receptor.

scholarly journals ErbB3 is involved in activation of phosphatidylinositol 3-kinase by epidermal growth factor.

1994 ◽  
Vol 14 (6) ◽  
pp. 3550-3558 ◽  
Author(s):  
S P Soltoff ◽  
K L Carraway ◽  
S A Prigent ◽  
W G Gullick ◽  
L C Cantley
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Kinase Activity ◽  
Egf Receptor ◽  
A549 Cells ◽  
Sh2 Domain ◽  
Recognition Sequence ◽  
A431 Cells ◽  
Erbb2 Protein ◽  
Epidermal Growth

Conflicting results concerning the ability of the epidermal growth factor (EGF) receptor to associate with and/or activate phosphatidylinositol (PtdIns) 3-kinase have been published. Despite the ability of EGF to stimulate the production of PtdIns 3-kinase products and to cause the appearance of PtdIns 3-kinase activity in antiphosphotyrosine immunoprecipitates in several cell lines, we did not detect EGF-stimulated PtdIns 3-kinase activity in anti-EGF receptor immunoprecipitates. This result is consistent with the lack of a phosphorylated Tyr-X-X-Met motif, the p85 Src homology 2 (SH2) domain recognition sequence, in this receptor sequence. The EGF receptor homolog, ErbB2 protein, also lacks this motif. However, the ErbB3 protein has seven repeats of the Tyr-X-X-Met motif in the carboxy-terminal unique domain. Here we show that in A431 cells, which express both the EGF receptor and ErbB3, PtdIns 3-kinase coprecipitates with the ErbB3 protein (p180erbB3) in response to EGF. p180erbB3 is also shown to be tyrosine phosphorylated in response to EGF. In contrast, a different mechanism for the activation of PtdIns 3-kinase in response to EGF occurs in certain cells (PC12 and A549 cells). Thus, we show for the first time that ErbB3 can mediate EGF responses in cells expressing both ErbB3 and the EGF receptor.

scholarly journals Rapid uptake of tyrphostin into A431 human epidermoid cells is followed by delayed inhibition of epidermal growth factor (EGF)-stimulated EGF receptor tyrosine kinase activity.

1991 ◽  
Vol 11 (5) ◽  
pp. 2697-2703 ◽  
Author(s):  
C A Faaland ◽  
F H Mermelstein ◽  
J Hayashi ◽  
J D Laskin
Keyword(s):  
Cell Cycle ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Tyrosine Kinase Activity ◽  
A431 Cells ◽  
Epidermal Growth

Treatment of A431 human epidermoid cells with epidermal growth factor (EGF; 20 nM) results in decreased proliferation. This is associated with blockage of the cells in the S and/or G2 phases of the cell cycle. We found that tyrphostin, a putative tyrosine kinase inhibitor, in the range of 50 to 100 microM, partially reversed the growth-inhibitory and cell cycle changes induced by EGF. By using high-pressure liquid chromatography with electrochemical detection, we found that tyrphostin was readily incorporated into A431 cells, reaching maximal levels within 1 h. Although tyrphostin (50 to 100 microM) had no effect on high-affinity binding of EGF to its receptor in A431 cells for up to 24 h, the compound partially inhibited EGF-stimulated EGF receptor tyrosine kinase activity. However, this effect was evident only after prolonged treatment of the cells (4 to 24 h) with the drug. When the peak intracellular concentration of tyrphostin occurred (1 h), no inhibition of tyrosine kinase activity was observed. After both 1 and 24 h, tyrphostin was a less effective inhibitor of tyrosine kinase activity than the potent tumor promoter 12-O-tetradecanoyl phorbol-13-acetate, which almost completely blocked EGF receptor autophosphorylation. On the basis of our data, we hypothesize that tyrphostin is not a competitive inhibitor of the EGF receptor tyrosine kinase in intact cells and that it functions by an indirect mechanism.

Rapid uptake of tyrphostin into A431 human epidermoid cells is followed by delayed inhibition of epidermal growth factor (EGF)-stimulated EGF receptor tyrosine kinase activity

1991 ◽  
Vol 11 (5) ◽  
pp. 2697-2703
Author(s):  
C A Faaland ◽  
F H Mermelstein ◽  
J Hayashi ◽  
J D Laskin
Keyword(s):  
Cell Cycle ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Tyrosine Kinase Activity ◽  
A431 Cells ◽  
Epidermal Growth

Treatment of A431 human epidermoid cells with epidermal growth factor (EGF; 20 nM) results in decreased proliferation. This is associated with blockage of the cells in the S and/or G2 phases of the cell cycle. We found that tyrphostin, a putative tyrosine kinase inhibitor, in the range of 50 to 100 microM, partially reversed the growth-inhibitory and cell cycle changes induced by EGF. By using high-pressure liquid chromatography with electrochemical detection, we found that tyrphostin was readily incorporated into A431 cells, reaching maximal levels within 1 h. Although tyrphostin (50 to 100 microM) had no effect on high-affinity binding of EGF to its receptor in A431 cells for up to 24 h, the compound partially inhibited EGF-stimulated EGF receptor tyrosine kinase activity. However, this effect was evident only after prolonged treatment of the cells (4 to 24 h) with the drug. When the peak intracellular concentration of tyrphostin occurred (1 h), no inhibition of tyrosine kinase activity was observed. After both 1 and 24 h, tyrphostin was a less effective inhibitor of tyrosine kinase activity than the potent tumor promoter 12-O-tetradecanoyl phorbol-13-acetate, which almost completely blocked EGF receptor autophosphorylation. On the basis of our data, we hypothesize that tyrphostin is not a competitive inhibitor of the EGF receptor tyrosine kinase in intact cells and that it functions by an indirect mechanism.

scholarly journals Epidermal growth factor (EGF) stimulates association and kinase activity of Raf-1 with the EGF receptor.

1991 ◽  
Vol 11 (2) ◽  
pp. 913-919 ◽  
Author(s):  
H App ◽  
R Hazan ◽  
A Zilberstein ◽  
A Ullrich ◽  
J Schlessinger ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Sodium Dodecyl ◽  
Specific Protein ◽  
Kinase Assay ◽  
Downstream Effector ◽  
Epidermal Growth

Raf-1 serine- and threonine-specific protein kinase is transiently activated in cells expressing the epidermal growth factor (EGF) receptor upon treatment with EGF. The stimulated EGF receptor coimmunoprecipitates with Raf-1 kinase and mediates protein kinase C-independent phosphorylation of Raf-1 on serine residues. Hyperphosphorylated Raf-1 has lower mobility on sodium dodecyl sulfate gels and has sixfold-increased activity in immunocomplex kinase assay with histone H1 or Raf-1 sequence-derived peptide as a substrate. Raf-1 activation requires kinase-active EGF receptor; a point mutant lacking tyrosine kinase activity in inactive in Raf-1 coupling and association. It is noteworthy that tyrosine phosphorylation of c-Raf-1 induced by EGF was not detected in these cells. These observations suggest that Raf-1 kinase may act as an important downstream effector of EGF signal transduction.

scholarly journals Multiplexed Evaluation of a Cell-Based Assay for the Detection of Antidrug Neutralizing Antibodies to Panitumumab in Human Serum Using Automated Fluorescent Microscopy

2010 ◽  
Vol 15 (6) ◽  
pp. 644-652 ◽  
Author(s):  
Jason Pennucci ◽  
Steve Swanson ◽  
Arunan Kaliyaperumal ◽  
Shalini Gupta
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Human Serum ◽  
Neutralizing Antibodies ◽  
Egf Receptor ◽  
Fluorescent Microscopy ◽  
Positive Control ◽  
A431 Cells ◽  
Assay Sensitivity ◽  
Epidermal Growth

The method described here employs a high-content cell-based assay format for the detection of neutralizing antibodies (NAbs) to panitumumab, a fully human monoclonal antagonistic antibody to the human epidermal growth factor (EGF) receptor in human serum (screening assay). A specificity assay was also developed and qualified to confirm that the neutralizing activity was attributable to the presence of NAbs and not due to serum interference (serum interference assay). The ArrayScan IV HCS reader was used for the measurement of tyrosine phosphorylation of the epidermal growth factor receptor (EGFR) and STAT-1 redistribution between the cytoplasm and nucleus in the human epidermoid carcinoma cell line A431. Assay conditions were developed by (1) optimizing the response of the A431 cells to recombinant human EGF in pooled human serum, (2) evaluating the ability of panitumumab to inhibit the EGF response, and (3) assessing the assay’s sensitivity for detecting a positive control affinity purified rabbit polyclonal anti-panitumumab antibody. Panitumumab dose-dependently inhibited 4 ng/mL EGF, and the positive control antibody showed a dose-dependent neutralization of 50 ng/mL panitumumab. The experiments indicated that in comparison to STAT-1 translocation, EGFR phosphorylation was the optimal endpoint for the screening and serum interference assays. Assay cut points were derived for the screening and serum interference assays by obtaining normalized ratios of mean fluorescence intensity values obtained with EGFR phosphorylation by testing sera from healthy human donor sera. The assay sensitivity was determined to be 0.125 µg/mL for the positive control antibody.

scholarly journals Conversion of epidermal growth factor (EGF) into a stimulatory ligand for A431-cell growth by herbimycin A by decreasing the level of expression of EGF receptor

1994 ◽  
Vol 301 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Y Murakami ◽  
H Fukazawa ◽  
S Mizuno ◽  
Y Uehara
Keyword(s):  
Growth Factor ◽  
Cell Growth ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Affinity Binding ◽  
Receptor Kinase ◽  
A431 Cells ◽  
Intact Cells ◽  
Herbimycin A ◽  
Epidermal Growth

We examined effect of the tyrosine kinase inhibitor herbimycin A on A431 human epidermoid carcinoma cells which over-express epidermal growth factor (EGF) receptor. Herbimycin A inhibited the autophosphorylation of EGF-stimulated receptors in intact cells both time- and dose-dependently. The inhibition was found to be due to a decrease in the level of expression of the receptor amount, because herbimycin A equally decreased the receptor quantity and EGF-stimulated receptor kinase activity in intact cells, but did not exhibit a direct inhibitory effect on EGF receptor kinase activity in vitro. The decrease of the level of EGF receptor was also confirmed by 125I-EGF binding to herbimycin A-treated cells, and Scatchard analysis showed that the decrease in the receptor number occurred in the major population of the low-affinity binding ones, whereas the number with high-affinity binding was unaffected. Interestingly, although the proliferation of A431 cells was inhibited by EGF, herbimycin A converted EGF into a stimulatory ligand for cell growth, as determined by both cell number and DNA synthesis. These findings indicated that herbimycin A decreased the level of expression of EGF receptor by a mechanism other than inactivation of the receptor kinase and reversed the transformed phenotype of A431 cells to a normal one in the proliferative response to EGF.

scholarly journals Localization of the epidermal growth factor (EGF) receptor within the endosome of EGF-stimulated epidermoid carcinoma (A431) cells.

1986 ◽  
Vol 102 (2) ◽  
pp. 500-509 ◽  
Author(s):  
K Miller ◽  
J Beardmore ◽  
H Kanety ◽  
J Schlessinger ◽  
C R Hopkins
Keyword(s):  
Acid Phosphatase ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Epidermoid Carcinoma ◽  
Egf Receptors ◽  
A431 Cells ◽  
Thin Sections ◽  
Receptor Complexes ◽  
Epidermal Growth

We have followed the internalization pathway of both epidermal growth factor (EGF) and its receptor in human epidermoid carcinoma (A431) cells. Using EGF conjugated with horseradish peroxidase and anti-receptor monoclonal antibodies (TL5 and EGFR1) coupled either directly or indirectly to colloidal gold we have identified an extensive elaboration of endosomal compartments, consisting of a peripheral branching network of tubular cisternae connected to vacuolar elements that contain small vesicles and a pericentriolar compartment consisting of a tubular cisternal network connected to multivesicular bodies. Immunocytochemistry on frozen thin sections using receptor-specific antibody-gold revealed that at 4 degrees C in the presence of EGF, receptors were mainly on the plasma membrane and, to a lesser extent, within some elements of both the peripheral and pericentriolar endosomal compartments. Upon warming to 37 degrees C there was an EGF-dependent redistribution of most binding sites, first to the peripheral endosome compartment and then to the pericentriolar compartment and lysosomes. Upon warming only to 20 degrees C the ligand-receptor complex accumulated in the pericentriolar compartment. Acid phosphatase cytochemistry identifies hydrolytic activity only within secondary lysosomes and trans cisternae of the Golgi stacks. Together these observations suggest that the prelysosomal endosome compartment extends to the pericentriolar complex and that the transfer of EGF receptor complexes to the acid phosphatase-positive lysosome involves a discontinuous, temperature-dependent step.

scholarly journals Signal transduction by epidermal growth factor and heregulin via the kinase-deficient ErbB3 protein

1998 ◽  
Vol 334 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Hong-Hee KIM ◽  
Ulka VIJAPURKAR ◽  
Nathan J. HELLYER ◽  
Dolores BRAVO ◽  
John G. KOLAND
Keyword(s):  
Signal Transduction ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Tyrosine Kinase Activity ◽  
Epidermal Growth ◽  
Protein Tyrosine Kinase Activity

The role of protein tyrosine kinase activity in ErbB3-mediated signal transduction was investigated. ErbB3 was phosphorylated in vivo in response to either heregulin (HRG) in cells expressing both ErbB3 and ErbB2, or epidermal growth factor (EGF) in cells expressing both ErbB3 and EGF receptor. A recombinant receptor protein (ErbB3-K/M, in which K/M stands for Lys → Met amino acid substitution) containing an inactivating mutation in the putative ATP-binding site was also phosphorylated in response to HRG and EGF. Both the wild-type ErbB3 and mutant ErbB3-K/M proteins transduced signals to phosphatidylinositol 3-kinase, Shc and mitogen-activated protein kinases. Separate kinase-inactivating mutations in the EGF receptor and ErbB2 proteins abolished ErbB3 phosphorylation and signal transduction activated by EGF and HRG respectively. Hence the protein tyrosine kinase activity necessary for growth factor signalling via the ErbB3 protein seems to be provided by coexpressed EGF and ErbB2 receptor proteins.

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