TY - JOUR
T1 - Tumor promoter enhances mitogenesis by PDGF with little effect on PDGF binding
AU - Eide, Brock L.
AU - Krebs, Edwin G.
AU - Ross, Russell
AU - Pike, Linda J.
AU - Bowen‐Pope, Daniel F.
PY - 1986/2
Y1 - 1986/2
N2 - 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 125l‐platelet‐derived growth factor (125I‐PDGF), and does not affect the affinity of 125I‐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 125I‐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.
AB - 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 125l‐platelet‐derived growth factor (125I‐PDGF), and does not affect the affinity of 125I‐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 125I‐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.
UR - http://www.scopus.com/inward/record.url?scp=0022648156&partnerID=8YFLogxK
U2 - 10.1002/jcp.1041260215
DO - 10.1002/jcp.1041260215
M3 - Article
C2 - 3003126
AN - SCOPUS:0022648156
SN - 0021-9541
VL - 126
SP - 254
EP - 258
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 2
ER -