scholarly journals Insulin-like effects of epidermal growth factor and insulin-like growth factor-I on [3H]2-deoxyglucose uptake, diacylglycerol generation and protein kinase C activation in BC3H-1 myocytes

1989 ◽  
Vol 261 (3) ◽  
pp. 927-934 ◽  
Author(s):  
R V Farese ◽  
G P Nair ◽  
C G Sierra ◽  
M L Standaert ◽  
R J Pollet ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Kinase C ◽  
Igf I ◽  
Epidermal Growth ◽  
Hydrolysis Of

Epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) were found to provoke increases in [3H]2-deoxyglucose uptake, diacylglycerol (DAG) generation and membrane-bound protein kinase C activity in BC3H-1 myocytes. These effects were similar to those provoked by insulin. The increases in DAG did not appear to be derived from hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) or phosphatidylinositol, but may have been derived from synthesis of phosphatidic acid de novo, and hydrolysis of phosphatidylcholine, as revealed by studies with [3H]glycerol and [3H]choline respectively. Accordingly, both EGF and IGF-I increased acute [3H]glycerol labelling of DAG (and other lipids) and [3H]choline labelling of phosphocholine. These labelling responses were similar in time course, suggesting that they are closely coupled. Our findings suggest that EGF and IGF-I, like insulin, increase DAG-protein kinase C signalling, apparently by activating co-ordinated lipid-synthesis and -hydrolysis responses, which are distinctly different from the PIP2-hydrolysis response.

Receptors for epidermal growth factor and insulin-like growth factor-I on preimplantation trophoderm of the pig

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 221-227
Author(s):  
A.N. Corps ◽  
D.R. Brigstock ◽  
C.J. Littlewood ◽  
K.D. Brown
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Molecular Mass ◽  
Cross Linking ◽  
Relative Molecular Mass ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Epidermal Growth ◽  
Growth Factor I

125I-labelled epidermal growth factor (125I-EGF) and 125I-labelled insulin-like growth factor-I (125I-IGF-I) bound to trophoderm cells from pig blastocysts obtained on days 15–19 of pregnancy. Specific binding was detected on freshly isolated cell suspensions and on cells cultured for several days. The binding of 125I-EGF was inhibited by increasing concentrations of EGF, but not by various other growth factors and hormones. Chemical cross-linking of 125I-EGF to its receptors using disuccinimidyl suberate (DSS) revealed a radiolabelled band of relative molecular mass 160,000, similar to that identified as the EGF receptor in other cell types. The binding of 125I-IGF-I was inhibited by both IGF-I and insulin, indicating that the receptors were either type I IGF receptors or insulin receptors. Cross-linking of 125I-IGF-I to serum-free supernatants from trophoderm cultures showed that the cells secreted an IGF-binding protein, giving a complex of relative molecular mass about 45,000. The presence of receptors for EGF and IGF/insulin suggests that these factors could be involved in regulating the growth and development of the early blastocyst.

Mechanism of sodium transport inhibition by epidermal growth factor in cortical collecting ducts

1991 ◽  
Vol 261 (5) ◽  
pp. F896-F903 ◽  
Author(s):  
V. M. Vehaskari ◽  
J. Herndon ◽  
L. L. Hamm
Keyword(s):  
Signal Transduction ◽  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Na Transport ◽  
Kinase C ◽  
Transport Inhibition ◽  
Collecting Ducts ◽  
Epidermal Growth

Epidermal growth factor (EGF) inhibits Na transport in the cortical collecting ducts (CCD). To gain insight into the signal transduction of this effect, several potential mechanisms were examined in rabbit CCD perfused in vitro. Pretreatment with pertussis toxin, indomethacin, or the protein kinase C inhibitor H7 did not prevent the acute 34-50% decrease in lumen-to-bath 22Na flux (JNa) on exposure to peritubular EGF, indicating that the inhibition is not mediated by a Gi protein, prostaglandin E2 (PGE2), or protein kinase C. Inhibition of the basolateral Na-H exchanger was also without an effect. Lowering the bath Ca concentration from 1.2 to 0.11 mM did not prevent the inhibition of JNa by EGF (JNa decreased significantly by 38.7 +/- 6.9% and 29.1 +/- 5.3%, respectively); in contrast, reduction of the bath free Ca to 0.005 mM totally abolished the effect of EGF. The response to EGF was also assessed in the setting of chronic stimulation of Na transport; inhibition of JNa by EGF was still observed in CCD from remnant kidneys and in CCD from mineralocorticoid-treated rabbits. The results demonstrate that the inhibition of CCD Na transport by EGF is dependent on peritubular Ca. This suggests that the signal transduction involves Ca influx across the basolateral membrane and that increased cytosolic free Ca may be a common pathway for the counterregulatory control of Na reabsorption by several agonists.

scholarly journals Regulation of epidermal-growth-factor-receptor signal transduction by cis-unsaturated fatty acids. Evidence for a protein kinase C-independent mechanism

1991 ◽  
Vol 278 (3) ◽  
pp. 679-687 ◽  
Author(s):  
X Casabiell ◽  
A Pandiella ◽  
F F Casanueva
Keyword(s):  
Signal Transduction ◽  
Fatty Acids ◽  
Protein Kinase C ◽  
Oleic Acid ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Kinase C ◽  
Epidermal Growth

The effect of acute treatment with non-esterified fatty acids (NEFA) on transmembrane signalling has been investigated in three different cell lines. In EGFR T17 cells, pretreatment with cis-unsaturated (oleic and palmitoleic acids) NEFA, but not with saturated or trans-unsaturated NEFA, inhibited the epidermal-growth-factor (EGF)-induced increases in cytosolic [Ca2+], membrane potential and Ins(1,4,5)P3 generation. The blocking effect was found to be time- and dose-dependent and rapidly reversible after washout. However, oleic acid treatment did not block either binding of 125I-EGF to its receptor or EGF-induced autophosphorylation of the EGF receptor. The mechanism of action of NEFA could not be attributed to protein kinase C activation, since (i) down-regulation of the enzyme by long-term treatment with phorbol esters did not prevent blockade by oleic acid, and (ii) the effects of acutely administered phorbol ester and oleic acid were additive. In this cell line, signalling at bradykinin and bombesin receptors was also impaired by oleic acid. In A431 cells, oleic acid also blocked signal transduction at the EGF and B2 bradykinin receptors. Finally, in PC12 cells, oleic acid blocked the Ca2+ influx mediated by the activation of B2 bradykinin receptors. In conclusion: (1) NEFA block signal transduction by interfering with receptor-phospholipase C or phospholipase C-substrate interaction without preventing ligand binding; (2) NEFA do not act by a protein kinase C-mediated mechanism; (3) the effect of NEFA is dependent on their configuration rather than hydrophobicity or chain length; (4) this effect is evident in several different cell lines and receptor systems.

scholarly journals Induction of heparin-binding epidermal growth factor-like growth factor mRNA by protein kinase C activators

1994 ◽  
Vol 46 (3) ◽  
pp. 690-695 ◽  
Author(s):  
Mian-Shin Tan ◽  
Jer-Chia Tsai ◽  
Yau-Jiunn Lee ◽  
Hung-Chun Chen ◽  
Shyi-Jang Shin ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Heparin Binding ◽  
Kinase C ◽  
Protein Kinase C Activators ◽  
Epidermal Growth

scholarly journals Epidermal Growth Factor Activates Phosphoinositide Turnover and Protein Kinase C in BALB/MK Keratinocytes

1988 ◽  
Vol 2 (9) ◽  
pp. 799-805 ◽  
Author(s):  
Jorge Moscat ◽  
Christopher J. Molloy ◽  
Timothy P. Fleming ◽  
Stuart A. Aaronson
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Phosphoinositide Turnover ◽  
Kinase C ◽  
Epidermal Growth
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