Expression of transforming growth factor b1, b2, b3 in neuroendocrine tumors of the digestive system
1994 (English)In: Anticancer Res, Vol. 14, 2085- p.Article in journal (Refereed) Published
Ligand induced activation of the beta-receptor for platelet-derived growth factor (PDGF) leads to activation of Src family tyrosine kinases. We have explored the possibility that the receptor itself is a substrate for Src. We show that Tyr934 in the kinase domain of the PDGF receptor is phosphorylated by Src. Cell lines expressing a beta-receptor mutant, in which Tyr934 was replaced with a phenyalanine residue, showed reduced mitogenic signaling in response to PDGF-BB. In contrast, the mutant receptor mediated increased signals for chemotaxis and actin reorganization. Whereas the motility responses of cells expressing wild-type beta-receptors were attenuated by inhibition of phosphatidylinositol 3'-kinase, those of cells expressing the mutant receptor were only slightly influenced. In contrast, PDGF-BB-induced chemotaxis of the cells with the mutant receptor was attenuated by inhibition of protein kinase C, whereas the chemotaxis of cells expressing the wild-type beta-receptor was less affected. Moreover, the PDGF-BB-stimulated tyrosine phosphorylation of phospholipase C-gamma was increased in the mutant receptor cells compared with wild-type receptor cells. In conclusion, the characteristics of the Y934F mutant suggest that the phosphorylation of Tyr934 by Src negatively modulates a signal transduction pathway leading to motility responses which involves phospholipase C-gamma, and shifts the response to increased mitogenicity.
Place, publisher, year, edition, pages
1994. Vol. 14, 2085- p.
1-Phosphatidylinositol 3-Kinase, Chemotaxis, Phospholipase C, Platelet-Derived Growth Factor
IdentifiersURN: urn:nbn:se:uu:diva-54639OAI: oai:DiVA.org:uu-54639DiVA: diva2:82548