Exp Mol Med.  2003 Apr;35(2):118-124.

Activation of epidermal growth factor receptor is responsible for pervanadate-induced phospholipase D activation

• Kim YR
• Cha HY
• Lim K
• Hwang BD
• Hoe KL
• Namgung U
• Park SK

Abstract

Pervanadate, a complex of vanadate and H2O2, has an insulin mimetic effect, and acts as an inhibitor of protein tyrosine phosphatase. Pervanadate-induced phospholipase D (PLD) activation is known to be dependent on the tyrosine phosphorylation of cellular proteins and protein kinase C (PKC) activation, and yet underlying molecular mechanisms are not clearly understood. Here, we investigated the signaling pathway of pervanadate-induced PLD activation in Rat2 fibroblasts. Pervanadate increased PLD activity in dose- and time- dependent manner. Protein tyrosine kinase inhibitor, genistein, blocked PLD activation. Interestingly, AG-1478, a specific inhibitor of the tyrosine kinase activity of epidermal growth factor receptor (EGFR) blocked not only the PLD activation completely but also phosphorylation of p38 mitogen- activated protein kinase (MAPK). However, AG-1295, an inhibitor specific for the tyrosine kinase activity of pletlet drived growth factor receptor (PDGFR) did not show any effect on the PLD activation by pervanadate. We further found that pervanadate increased phosphorylation levels of p38, extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK). SB203580, a p38 MAPK inhibitor, blocked the PLD activation completely. However, the inhibitions of ERK by the treatment of PD98059 or of JNK by the overexpression of JNK interacting peptide JBD did not show any effect on pervanadate-induced PLD activation. Inhibition or down-regulation of PKC did not alter the pervanadate-induced PLD activation in Rat2 cells. Thus, these results suggest that pervanadate-induced PLD activation is coupled to the transactivation of EGFR by pervanadate resulting in the activation of p38 MAP kinase.

Keyword

mitogen-activated protein kinases; phospholipase D; proto-oncogene protein pp60(c-src); receptor; dpidermal growth factor; vanadates

MeSH Terms

Animals
Cell Line
Enzyme Activation/drug effects
Fibroblasts
Mitogen-Activated Protein Kinases/metabolism
Phospholipase D/*metabolism
Rats
Receptor, Epidermal Growth Factor/*agonists/*metabolism
Vanadates/*pharmacology
src-Family Kinases/metabolism