Short (1-10 min) pretreatment of intact cells with activators of protein kinase C (e.g. phorbol-12 myristate, 13-acetate, PMA) affects the activity of a variety of surface receptors (for growth factors, hormones and neurotransmitters), with inhibition of transmembrane signal generation. In two types of fibroblasts we demonstrate that the PDGF receptor is unaffected by PMA. Exposure to PMA at concentrations up to 100 nM for 10 min failed to inhibit either one of the agonist-induced, receptor-coupled responses of PDGF: the autophosphorylation of receptor molecules at tyrosine residues, and the hydrolysis of membrane polyphosphoinositides. In contrast, the EGF receptor autophosphorylation (in A 431 cells) and the bombesin-induced phosphoinositide hydrolysis were readily inhibited by PMA. Feed-back inhibition of surface receptors by protein kinase C-mediated phosphorylation is therefore not general, and cannot be the only process responsible for the attenuation of receptor-mediated responses in eukaryotic cells.
|Titolo:||PDGF-induced receptor phosphorylation and phosphoinositide hydrolysis are unaffected by protein kinase C activation in mouse Swiss 3T3 and human skin fibroblasts|
|Autori interni:||VICENTINI, LUCIA (Secondo)|
|Parole Chiave:||Animals; Platelet-Derived Growth Factor; Tetradecanoylphorbol Acetate; Phosphotyrosine; Enzyme Activation; Humans; Phosphatidylinositols; Bombesin; Tyrosine; Protein-Tyrosine Kinases; Mice; Receptors, Cell Surface; Phosphorylation; Cells, Cultured; Receptors, Platelet-Derived Growth Factor; Protein Kinase C|
|Settore Scientifico Disciplinare:||Settore BIO/14 - Farmacologia|
|Data di pubblicazione:||29-mag-1986|
|Digital Object Identifier (DOI):||10.1016/0006-291X(86)91216-7|
|Appare nelle tipologie:||01 - Articolo su periodico|