Activation of phospholipase D in rabbit neutrophils by fMet-Leu-Phe is mediated by a pertussis toxin-sensitive GTP-binding protein that may be distinct from a phospholipase C-regulating protein

Abstract

Stimulation by N-formyl-Met-Leu-Phe (fMLP) of rabbit peritoneal neutrophils, in which phosphatidylcholine was preferentially labeled with l- O-[ 3H]octadecyl lyso platelet-activating factor, activated phospholipase D, resulting in the formation of [ 3H]PA from [ 3H]PC. A direct activator of GTP-binding proteins (G-proteins), NaF, also stimulated [ 3H]PA formation. fMLP-stimulated [ 3H]PA formation was inhibited by pertussis toxin (IAP) in a time- and dose-dependent manner. IAP also inhibited fMLP-stimulated IP 3 formation, but the inhibition of IP 3 formation was significantly greater than that of [ 3H]PA formation. These results indicate that activation of phospholipase D by fMLP in rabbit neutrophils is mediated by an IAP-sensitive G-protein that may be distinct from a phospholipase C-regulating protein.