scholarly journals Inhibition of tyrosine kinase activity of the epidermal growth factor (EGF) receptor by a truncated receptor form that binds to EGF: role for interreceptor interaction in kinase regulation.

1989 ◽  
Vol 9 (2) ◽  
pp. 671-677 ◽  
Author(s):  
A Basu ◽  
M Raghunath ◽  
S Bishayee ◽  
M Das
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Binding Site ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Kinase Domain ◽  
Tyrosine Kinase Activity ◽  
Truncated Receptor ◽  
Epidermal Growth

The tyrosine kinase activity of the epidermal growth factor (EGF) receptor is regulated by a truncated receptor of 100 kilodaltons (kDa) that contains the EGF-binding site but not the kinase domain. The inhibition of kinase is not due to competition for available EGF or for the kinase substrate-binding site. Chemical cross-linking studies suggest that the 100-kDa receptor may form a heterodimer with the intact EGF receptor. Structurally related receptor kinases, such as the platelet-derived growth factor receptor, the insulin receptor, and the Neu receptor, were not inhibited by the 100-kDa receptor. The results indicate that (i) the inhibition was specific for the EGF receptor, (ii) the kinase domain had little or no role in determining target specificity, and (iii) the regulation of kinase may be due to a specific interaction of the 100-kDa receptor with the ligand-binding domain of the EGF receptor kinase.

Inhibition of tyrosine kinase activity of the epidermal growth factor (EGF) receptor by a truncated receptor form that binds to EGF: role for interreceptor interaction in kinase regulation

1989 ◽  
Vol 9 (2) ◽  
pp. 671-677
Author(s):  
A Basu ◽  
M Raghunath ◽  
S Bishayee ◽  
M Das
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Binding Site ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Kinase Domain ◽  
Tyrosine Kinase Activity ◽  
Truncated Receptor ◽  
Epidermal Growth

The tyrosine kinase activity of the epidermal growth factor (EGF) receptor is regulated by a truncated receptor of 100 kilodaltons (kDa) that contains the EGF-binding site but not the kinase domain. The inhibition of kinase is not due to competition for available EGF or for the kinase substrate-binding site. Chemical cross-linking studies suggest that the 100-kDa receptor may form a heterodimer with the intact EGF receptor. Structurally related receptor kinases, such as the platelet-derived growth factor receptor, the insulin receptor, and the Neu receptor, were not inhibited by the 100-kDa receptor. The results indicate that (i) the inhibition was specific for the EGF receptor, (ii) the kinase domain had little or no role in determining target specificity, and (iii) the regulation of kinase may be due to a specific interaction of the 100-kDa receptor with the ligand-binding domain of the EGF receptor kinase.

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.

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.

scholarly journals The epidermal growth factor receptor from prostate cells is dephosphorylated by a prostate-specific phosphotyrosyl phosphatase.

1988 ◽  
Vol 8 (12) ◽  
pp. 5477-5485 ◽  
Author(s):  
M F Lin ◽  
G M Clinton
Keyword(s):  
Acid Phosphatase ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Carcinoma Cells ◽  
Tyrosine Kinase Activity ◽  
Epidermal Growth

Human prostatic acid phosphatase (PAcP) has been found to have phosphotyrosyl-protein phosphatase activity (H. C. Li, J. Chernoff, L. B. Chen, and A. Kirschonbaun, Eur. J. Biochem. 138:45-51, 1984; M.-F. Lin and G. M. Clinton, Biochem. J. 235:351-357, 1986) and has been suggested to negatively regulate phosphotyrosine levels, at least in part, by inhibition of tyrosine protein kinase activity (M.-F. Lin and G. M. Clinton, Adv. Protein Phosphatases 4:199-228, 1987; M.-F. Lin, C. L. Lee, and G. M. Clinton, Mol. Cell. Biol. 6:4753-4757, 1986). We investigated the molecular interaction of PAcP with a specific tyrosine kinase, the epidermal growth factor (EGF) receptor, from prostate carcinoma cells. Of several proteins phosphorylated in membrane vesicles from prostate carcinoma cells, PAcP selectively dephosphorylated the EGF receptor. The prostate EGF receptor was more efficiently dephosphorylated by PAcP than by another phosphotyrosyl phosphatase, potato acid phosphatase. Further characterization of the interaction of PAcP with the EGF receptor revealed that the optimal rate of dephosphorylation occurred at neutral rather than at acid pH. Thus, the enzyme that we formerly referred to as PAcP we now call prostatic phosphotyrosyl-protein phosphatase. Hydrolysis of phosphate from tyrosine residues in the immunoprecipitated EGF receptor catalyzed by purified prostatic phosphotyrosyl-protein phosphatase caused a 40 to 50% decrease in the receptor tyrosine kinase activity with angiotensin as the substrate. In contrast, autophosphorylation of the receptor was associated with an increase in tyrosine kinase activity.

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 Distinct structural specificities for functional coupling of the epidermal growth factor receptor to calcium-signalling versus phospholipase A2 responses

1991 ◽  
Vol 275 (3) ◽  
pp. 563-567 ◽  
Author(s):  
N Hack ◽  
B L Margolis ◽  
A Ullrich ◽  
J Schlessinger ◽  
K L Skorecki
Keyword(s):  
Arachidonic Acid ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Phospholipase A2 ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Functional Coupling ◽  
Tyrosine Kinase Activity ◽  
Epidermal Growth

Activation of phospholipase C (PLC), leading to a rise in cytosolic Ca2+, and of phospholipase A2 (PLA2) leading to a release of arachidonic acid, are among the early transmembrane signalling events that have been demonstrated in response to occupancy of the epidermal growth factor (EGF) receptor. The tyrosine kinase activity of the receptor has been shown to be necessary for both of these responses. This requirement for the tyrosine kinase activity could conceivably implicate a role for receptor autophosphorylation in the activation of PLA2. We now demonstrate that coupling of the EGF receptor to PLA2 was not impaired in a deletion mutant (CD126) devoid of the 126 amino acids from the C-terminus which include four major autophosphorylation sites. Functional coupling of the EGF receptor to PLA2 was demonstrated using three different experimental designs: (1) release of [14C]arachidonic acid from prelabelled intact cells. (2) release of [3H]arachidonic acid from prelabelled cells permeabilized with glass beads, and (3) direct measurement of PLA2 enzymic activity in cell-free extracts using an ‘in vitro’ assay employing exogenous phospholipid substrate. Functional coupling of the EGF receptor to PLA2 occurred despite the absence of a demonstrable Ca(2+)-signalling response and the detection of diminished but persistent PLC-gamma phosphorylation on tyrosine residues in the CD126 deletion mutants. These results point to a clear distinction in the biochemical mechanism and role for receptor autophosphorylation in functional coupling of the EGF receptor to PLA2 activation versus Ca2+ signalling.

scholarly journals The epidermal growth factor receptor from prostate cells is dephosphorylated by a prostate-specific phosphotyrosyl phosphatase

1988 ◽  
Vol 8 (12) ◽  
pp. 5477-5485
Author(s):  
M F Lin ◽  
G M Clinton
Keyword(s):  
Acid Phosphatase ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Carcinoma Cells ◽  
Tyrosine Kinase Activity ◽  
Epidermal Growth

Human prostatic acid phosphatase (PAcP) has been found to have phosphotyrosyl-protein phosphatase activity (H. C. Li, J. Chernoff, L. B. Chen, and A. Kirschonbaun, Eur. J. Biochem. 138:45-51, 1984; M.-F. Lin and G. M. Clinton, Biochem. J. 235:351-357, 1986) and has been suggested to negatively regulate phosphotyrosine levels, at least in part, by inhibition of tyrosine protein kinase activity (M.-F. Lin and G. M. Clinton, Adv. Protein Phosphatases 4:199-228, 1987; M.-F. Lin, C. L. Lee, and G. M. Clinton, Mol. Cell. Biol. 6:4753-4757, 1986). We investigated the molecular interaction of PAcP with a specific tyrosine kinase, the epidermal growth factor (EGF) receptor, from prostate carcinoma cells. Of several proteins phosphorylated in membrane vesicles from prostate carcinoma cells, PAcP selectively dephosphorylated the EGF receptor. The prostate EGF receptor was more efficiently dephosphorylated by PAcP than by another phosphotyrosyl phosphatase, potato acid phosphatase. Further characterization of the interaction of PAcP with the EGF receptor revealed that the optimal rate of dephosphorylation occurred at neutral rather than at acid pH. Thus, the enzyme that we formerly referred to as PAcP we now call prostatic phosphotyrosyl-protein phosphatase. Hydrolysis of phosphate from tyrosine residues in the immunoprecipitated EGF receptor catalyzed by purified prostatic phosphotyrosyl-protein phosphatase caused a 40 to 50% decrease in the receptor tyrosine kinase activity with angiotensin as the substrate. In contrast, autophosphorylation of the receptor was associated with an increase in tyrosine kinase activity.

Sign in / Sign up

Export Citation Format

Share Document