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

Osamu Kozawa, Peter Blume-Jensen, Carl-Henrik Heldin, Lars Rönnstrand

Research output: Contribution to journalArticlepeer-review


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.
Original languageEnglish
Pages (from-to)149-155
JournalEuropean Journal of Biochemistry
Issue number1
Publication statusPublished - 1997
Externally publishedYes

Bibliographical 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)

Subject classification (UKÄ)

  • Medicinal Chemistry

Free keywords

  • Complementary/geneticsDiglycerides/biosynthesisEnzyme Activation/drug effectsHumansModels
  • Arachidonic Acid/*metabolismBase SequenceCell LineDNA
  • BiologicalMutagenesis
  • Site-DirectedPhosphatidylinositol 3-KinasesPhosphatidylinositol Diacylglycerol-LyasePhosphoinositide Phospholipase CPhospholipase D/*metabolismPhosphotransferases (Alcohol Group Acceptor)/*metabolismPropranolol/pharmacologyProto-Oncogene Proteins c-kit/genetics/metabolismSecond Messenger SystemsStem Cell Factor/metabolism/*pharmacologyTransfectionType C Phospholipases/metabolism


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