Exp Mol Med.  2001 Sep;33(3):150-155.

ATP-induced focal adhesion kinase activity is negatively modulated by phospholipase D2 in PC12 cells

• Bae YS
• Ryu SH

Abstract

Extracellular ATP has been known to modulate various cellular responses including mitogenesis, secretion and morphogenic activity in neuronal cells. In the ATP-induced morphogenic activity, focal adhesion kinase(s) such as Fak have been suggested to play a critical role. Binding of ATP to its specific cell surface receptor in PC12 cells induces phospholipase D (PLD) activity. However, the role of PLD on ATP-induced Fak activation in PC12 cells remains unclear. In this study, we investigated the role of PLD on the ATP-induced Fak activation and paxillin phosphorylation using two established cell lines: wild type PLD2- and lipase-inactive mutant PLD2-inducible PC12 cells. Stimulation of cells with ATP caused PLD2 activation via classical protein kinase C activation. ATP also induced Fak activation, and paxillin phosphorylation, and were dramatically reduced by wild type PLD2 overexpression but not by lipase-inactive mutant PLD2 overexpression. When the PC12 cells were pretreated with propranolol, a specific inhibitor for phosphatidic acid phosphohydrolase resulting in the accumulation of PA, ATP-induced Fak activation and paxillin phosphorylation were also reduced. We found that inhibition of tyrosine phosphatases by pervanadate completely blocked PLD2-dependent Fak and paxillin dephosphorylation. Taken together, we suggest that PLD2 activity might play a negative role in ATP-induced Fak and paxillin phosphorylation possibly through tyrosine phosphatases.

Keyword

Focal adhesion kinase; Phosphatidic acid; Phospholipase D; Paxillin; Tyrosine phosphatase

MeSH Terms

Adenosine Triphosphate/*metabolism
Animal
Culture Media, Serum-Free
Cytoskeletal Proteins/metabolism
Enzyme Activation/drug effects
Enzyme Inhibitors/pharmacology
Focal Adhesions/metabolism
PC12 Cells
Phospholipase D/*metabolism
Phosphoproteins/metabolism
Phosphorylation
Propranolol/pharmacology
Protein Kinase C/antagonists & inhibitors
Protein-Tyrosine Kinase/*metabolism
Rats
Support, Non-U.S. Gov't
Vasodilator Agents/pharmacology