Non-radioisotopic method for thein vitro measurement of EGF receptor tyrosine kinase

2001 ◽  
Vol 46 (8) ◽  
pp. 683-685
Author(s):  
Gaoxiang Ge ◽  
Jing Wu ◽  
Qishui Lin
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Egf Receptor ◽  
Radioisotopic Method

scholarly journals Multiple functions of let-23, a Caenorhabditis elegans receptor tyrosine kinase gene required for vulval induction.

Genetics ◽  
1991 ◽  
Vol 128 (2) ◽  
pp. 251-267 ◽  
Author(s):  
R V Aroian ◽  
P W Sternberg
Keyword(s):  
Caenorhabditis Elegans ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Egf Receptor ◽  
Kinase Gene ◽  
Multiple Functions ◽  
Tyrosine Kinase Gene ◽  
Receptor Tyrosine Kinase Gene ◽  
Epidermal Growth ◽  
Mutant Phenotypes

Abstract The let-23 gene, which encodes a putative tyrosine kinase of the epidermal growth factor (EGF) receptor subfamily, has multiple functions during Caenorhabditis elegans development. We show that let-23 function is required for vulval precursor cells (VPCs) to respond to the signal that induces vulval differentiation: a complete loss of let-23 function results in no induction. However, some let-23 mutations that genetically reduce but do not eliminate let-23 function result in VPCs apparently hypersensitive to inductive signal: as many as five of six VPCs can adopt vulval fates, in contrast to the three that normally do. These results suggest that the let-23 receptor tyrosine kinase controls two opposing pathways, one that stimulates vulval differentiation and another that negatively regulates vulval differentiation. Furthermore, analysis of 16 new let-23 mutations indicates that the let-23 kinase functions in at least five tissues. Since various let-23 mutant phenotypes can be obtained independently, the let-23 gene is likely to have tissue-specific functions.

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.

Effect of tyrosine kinase inhibition on surfactant protein A gene expression during human lung development

1998 ◽  
Vol 274 (4) ◽  
pp. L542-L551 ◽  
Author(s):  
Jonathan M. Klein ◽  
Louis J. Dewild ◽  
Troy A. McCarthy
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Lung Tissue ◽  
Receptor Tyrosine Kinase ◽  
Lung Development ◽  
Egf Receptor ◽  
Fetal Lung ◽  
Surfactant Protein ◽  
Mrna Levels ◽  
Human Fetal Lung

Epidermal growth factor (EGF) stimulates surfactant protein (SP) A synthesis in human fetal lung explants. Ligand binding to the EGF receptor stimulates an intrinsic receptor tyrosine kinase with subsequent activation of second messengers. We hypothesized that inhibition of EGF-receptor tyrosine kinase activity would block SP-A expression in spontaneously differentiating cultured human fetal lung tissue. Midtrimester fetal lung explants were exposed for 4 days to genistein (a broad-range inhibitor of tyrosine kinases) and tyrphostin AG-1478 (a specific inhibitor of EGF-receptor tyrosine kinase). Genistein significantly decreased SP-A and SP-A mRNA levels without affecting either tissue viability or the morphological differentiation of alveolar type II cells. Tyrphostin AG-1478 also decreased SP-A content and SP-A mRNA levels in cultured fetal lung explants. Treatment with EGF could not overcome the inhibitory effects of either genistein or tyrphostin on SP-A; however, only tyrphostin inhibited EGF-receptor tyrosine phosphorylation. We conclude that specific inhibition of EGF-receptor tyrosine kinase with tyrphostin AG-1478 blocks the expression of SP-A during spontaneous differentiation of cultured human fetal lung tissue. Furthermore, exposure to genistein also decreases SP-A expression and blocks the effects of EGF in human fetal lung tissue without inhibiting EGF-receptor tyrosine phosphorylation. These findings support the importance of tyrosine kinase-dependent signal transduction pathways in the regulation of SP-A during human fetal lung development.

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