The effect of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) on the phosphorylation and function of α1b-adrenoceptors transfected into Rat-1 fibroblasts was studied. EGF and PDGF increased the phosphorylation of these adrenoceptors. The effect of EGF was blocked by tyrphostin AG1478 and that of PDGF was blocked by tyrphostin AG1296, inhibitors of the intrinsic tyrosine kinase activities of the receptors for these growth factors. Wortmannin, an inhibitor of phosphoinositide 3-kinase, blocked the α1b-adrenoceptor phosphorylation induced by EGF but not that induced by PDGF. Inhibition of protein kinase C blocked the adrenoceptor phosphorylation induced by EGF and PDGF. The ability of noradrenaline to increase [35S]guanosine 5´-[γ-thio]triphosphate ([35S]GTP[S]) binding in membrane preparations was used as an index of the functional coupling of the α1b-adrenoceptors and G-proteins. Noradrenaline-stimulated [35S]GTP[S] binding was markedly decreased in membranes from cells pretreated with EGF or PDGF. Our data indicate that: (i) activation of EGF and PDGF receptors induces phosphorylation of α1b-adrenoceptors, (ii) phosphatidylinositol 3-kinase is involved in the EGF response, but does not seem to play a major role in the action of PDGF, (iii) protein kinase C mediates this action of both growth factors and (iv) the phosphorylation of α1b-adrenoceptors induced by EGF and PDGF is associated with adrenoceptor desensitization.
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September 2000
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Research Article|
August 23 2000
Cross-talk between receptors with intrinsic tyrosine kinase activity and α1b-adrenoceptors
Luz DEL CARMEN MEDINA;
Luz DEL CARMEN MEDINA
*Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México, D.F. 04510
†Departamento de Biología de la Reproducción, División de CBS, Universidad Autónoma Metropolitana-Iztapalapa, Av. Michoacán y Purisima, México, D.F. 09340
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José VÁZQUEZ-PRADO;
José VÁZQUEZ-PRADO
*Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México, D.F. 04510
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J. Adolfo GARCÍA-SÁINZ
J. Adolfo GARCÍA-SÁINZ
1
*Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México, D.F. 04510
1To whom correspondence should be addressed (e-mail agarcia@ifisiol.unam.mx).
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Publisher: Portland Press Ltd
Received:
December 17 1999
Revision Received:
May 17 2000
Accepted:
June 22 2000
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 2000
2000
Biochem J (2000) 350 (2): 413–419.
Article history
Received:
December 17 1999
Revision Received:
May 17 2000
Accepted:
June 22 2000
Citation
Luz DEL CARMEN MEDINA, José VÁZQUEZ-PRADO, J. Adolfo GARCÍA-SÁINZ; Cross-talk between receptors with intrinsic tyrosine kinase activity and α1b-adrenoceptors. Biochem J 1 September 2000; 350 (2): 413–419. doi: https://doi.org/10.1042/bj3500413
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