Activation of phospholipase D induced by platelet-derived growth factor is dependent upon the level of phospholipase C-gamma 1.
The mechanism of phospholipase D (PLD) activation by platelet-derived growth factor (PDGF) was examined using a NIH 3T3 fibroblast cell line (3T3-gamma 1) that stably overexpresses PLC-gamma 1 isozyme. Immunoblot analysis revealed that 3T3-gamma 1 cells contained about 10-fold more PLC-gamma 1 than a control cell line (3T3-C) transfected with expression vector lacking PLC-gamma 1 cDNA. PDGF-stimulated PLD activation was 10-fold greater in 3T3-gamma 1 cells than in 3T3-C cells, indicating that PLD activation is dependent upon the level of PLC-gamma 1. Phorbol 12-myristate 13-acetate (PMA) treatment increased PLD activity to a similar extent in both 3T3-gamma 1 cells and control cells. Pretreatment with tyrosine kinase inhibitors including staurosporine and genistein decreased PLD activity by 82.6% and 87.2%, respectively, and completely blocked tyrosine phosphorylation of PDGF receptor and PLC-gamma 1 in 3T3-gamma 1 cells stimulated with PDGF. Moreover, down-regulation of protein kinase C by pretreatment of PMA caused complete inhibition of PDGF- and PMA-stimulated PLD activation. Therefore, these results suggest that PDGF-induced PLD activation may be a consequence of primary stimulation of PLC-gamma 1 and that PLD may play a role downstream from PLC-gamma 1 in PDGF-triggered mitogenesis.
Lee
Y H
YH
Department of Life Science, Pohang University of Science and Technology, Hyoja-Dong, Korea.
Kim
H S
HS
Pai
J K
JK
Ryu
S H
SH
Suh
P G
PG
D016475:3T3 Cells; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004789:Enzyme Activation; D019833:Genistein; D020404:Glycerophospholipids; D007295:Inositol Phosphates / Q000032:analysis; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D007529:Isoflavones / Q000494:pharmacology; D051379:Mice; D010712:Phosphatidic Acids / Q000032:analysis; D051966:Phospholipase C gamma; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
D000470:Alkaloids; D020404:Glycerophospholipids; D007295:Inositol Phosphates; D007527:Isoenzymes; D007529:Isoflavones; D010712:Phosphatidic Acids; D010982:Platelet-Derived Growth Factor; D011994:Recombinant Proteins; C051521:phosphatidylethanol; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D010739:Phospholipase D; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate