Involvement of phosphatidylinositol 3'-kinase in stem-cell-factor-induced phospholipase D activation and arachidonic acid release

Research output: Contribution to journalArticle

Abstract

We have shown previously that the stem cell factor (SCF) receptor undergoes phosphorylation on serine residues following ligand stimulation, and that this phopshorylation is dependent mainly on the activity of protein kinase C (PKC). In the present study, we have further investigated the molecular mechanisms behind SCF-stimulated activation of PKC, and found that SCF does not activate phosphatidylinositol-specific phospholipase C. In contrast, phospholipase D (PLD) is activated in response to SCF in a dose-dependent manner. Activation of PLD was not inhibited by calphostin C, an inhibitor of PKC. On the other hand, inhibitors of phosphatidylinositol PtdIns 3'-kinase (PtdIns 3'-kinase), i.e. wortmannin and LY294002, inhibited SCF-induced PLD activation. Moreover, a mutant SCF receptor in which Tyr721, which is responsible for activation of PtdIns 3'-kinase, is mutated to a phenylalanine residue was unable to mediate activation of PLD. Thus, PtdIns 3'-kinase appears to be essential for SCF-induced PLD activation. Furthermore, we demonstrate that phosphatidic acid (PtdH), generated through the action of PLD in response to SCF, is metabolized to diacylglycerol by dephosphorylation. Diacylglycerol can then activate PKC, and, moreover, after deacylation by a diacylglycerol lipase, yield arachidonic acid, an important second messenger in cell signaling.

Details

Authors
External organisations
  • External Organization - Unknown
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Medicinal Chemistry

Keywords

  • Complementary/genetics Diglycerides/biosynthesis Enzyme Activation/drug effects Humans Models, Arachidonic Acid/*metabolism Base Sequence Cell Line DNA, Biological Mutagenesis, Site-Directed Phosphatidylinositol 3-Kinases Phosphatidylinositol Diacylglycerol-Lyase Phosphoinositide Phospholipase C Phospholipase D/*metabolism Phosphotransferases (Alcohol Group Acceptor)/*metabolism Propranolol/pharmacology Proto-Oncogene Proteins c-kit/genetics/metabolism Second Messenger Systems Stem Cell Factor/metabolism/*pharmacology Transfection Type C Phospholipases/metabolism
Original languageEnglish
Pages (from-to)149-155
JournalEuropean Journal of Biochemistry
Volume248
Issue number1
Publication statusPublished - 1997
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Experimental Clinical Chemistry (013016010)