Epidermal growth factor stimulates guanine nucleotide binding activity and phosphorylation of ras oncogene proteins

Nature ◽  
1984 ◽  
Vol 310 (5973) ◽  
pp. 147-150 ◽  
Author(s):  
Tohru Kamata ◽  
James R. Feramisco
1993 ◽  
Vol 13 (1) ◽  
pp. 155-162
Author(s):  
R H Medema ◽  
A M de Vries-Smits ◽  
G C van der Zon ◽  
J A Maassen ◽  
J L Bos

A number of growth factors, including insulin and epidermal growth factor (EGF), induce accumulation of the GTP-bound form of p21ras. This accumulation could be caused either by an increase in guanine nucleotide exchange on p21ras or by a decrease in the GTPase activity of p21ras. To investigate whether insulin and EGF affect nucleotide exchange on p21ras, we measured binding of [alpha-32P]GTP to p21ras in cells permeabilized with streptolysin O. For this purpose, we used a cell line which expressed elevated levels of p21 H-ras and which was highly responsive to insulin and EGF. Stimulation with insulin or EGF resulted in an increase in the rate of nucleotide binding to p21ras. To determine whether this increased binding rate is due to the activation of a guanine nucleotide exchange factor, we made use of the inhibitory properties of a dominant negative mutant of p21ras, p21ras (Asn-17). Activation of p21ras by insulin and EGF in intact cells was abolished in cells infected with a recombinant vaccinia virus expressing p21ras (Asn-17). In addition, the enhanced nucleotide binding to p21ras in response to insulin and EGF in permeabilized cells was blocked upon expression of p21ras (Asn-17). From these data, we conclude that the activation of a guanine nucleotide exchange factor is involved in insulin- and EGF-induced activation of p21ras.


1993 ◽  
Vol 13 (1) ◽  
pp. 155-162 ◽  
Author(s):  
R H Medema ◽  
A M de Vries-Smits ◽  
G C van der Zon ◽  
J A Maassen ◽  
J L Bos

A number of growth factors, including insulin and epidermal growth factor (EGF), induce accumulation of the GTP-bound form of p21ras. This accumulation could be caused either by an increase in guanine nucleotide exchange on p21ras or by a decrease in the GTPase activity of p21ras. To investigate whether insulin and EGF affect nucleotide exchange on p21ras, we measured binding of [alpha-32P]GTP to p21ras in cells permeabilized with streptolysin O. For this purpose, we used a cell line which expressed elevated levels of p21 H-ras and which was highly responsive to insulin and EGF. Stimulation with insulin or EGF resulted in an increase in the rate of nucleotide binding to p21ras. To determine whether this increased binding rate is due to the activation of a guanine nucleotide exchange factor, we made use of the inhibitory properties of a dominant negative mutant of p21ras, p21ras (Asn-17). Activation of p21ras by insulin and EGF in intact cells was abolished in cells infected with a recombinant vaccinia virus expressing p21ras (Asn-17). In addition, the enhanced nucleotide binding to p21ras in response to insulin and EGF in permeabilized cells was blocked upon expression of p21ras (Asn-17). From these data, we conclude that the activation of a guanine nucleotide exchange factor is involved in insulin- and EGF-induced activation of p21ras.


1985 ◽  
Vol 5 (12) ◽  
pp. 3386-3396
Author(s):  
B Weissman ◽  
S A Aaronson

BALB-/MK-2 mouse epidermal keratinocytes required epidermal growth factor for proliferation and terminally differentiated in response to high Ca2+ concentration. Infection with retroviruses containing transforming genes of the src and ras oncogene families led to rapid loss of epidermal growth factor dependence, in some cases, accompanied by alterations in cellular morphology. The virus-altered cells continued to proliferate in the presence of high levels of extracellular calcium but exhibited alterations in normal keratinocyte terminal differentiation that appear to be specific to the particular oncogene. These alterations bore similarities to abnormalities in differentiation observed in naturally occurring squamous epithelial malignancies.


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