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Tumor promoter enhances mitogenesis by PDGF with little effect on PDGF binding
Author(s) -
Eide Brock L.,
Krebs Edwin G.,
Ross Russell,
Pike Linda J.,
BowenPope Daniel F.
Publication year - 1986
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041260215
Subject(s) - platelet derived growth factor receptor , internalization , protein kinase c , growth factor , platelet derived growth factor , receptor , ligand (biochemistry) , microbiology and biotechnology , biology , dna synthesis , phosphorylation , chemistry , biochemistry , in vitro
Preincubation of Swiss 3T3 cells with the tumor promoter 12‐0‐tetradecanoyl‐phorbol‐13‐acetate (TPA) at 37°C is observed to cause only a small (approximately 10%) decrease in maximal binding of 125 l‐platelet‐derived growth factor ( 125 I‐PDGF), and does not affect the affinity of 125 I‐PDGF binding to these cells. Under the same conditions, the affinity of the epidermal growth factor receptor is greatly reduced, possibly resulting from phosphorylation by protein kinase C. TPA is also shown to have no effect on the kinetics of internalization or degradation of bound 125 I‐PDGF. Although TPA has little or no effect on these properties of the PDGF receptor, it was found to act in a synergistic fashion with low, but not high, concentrations of PDGF to increase DNA synthesis by 3T3 cells. Since TPA has previously been shown to activate protein kinase C, these findings suggest that protein kinase C does not regulate the ligand‐binding properties of the PDGF receptor, and that the observed synergism between TPA and PDGF in stimulating mitogenesis reflects effects of TPA on other processes in the mitogenic pathway.