Direct activation of phospholipase A2 by GTP-binding protein in human peripheral polymorphonuclear leukocytes

Biochem Biophys Res Commun. 1992 Mar 16;183(2):708-13. doi: 10.1016/0006-291x(92)90540-2.

Abstract

In human peripheral polymorphonuclear leukocyte (PMN), 10% of PLA2 activity was found in the particulate fraction. In the particulate fraction, the activity of phospholipase A2 was enhanced 270% by 100 microM guanosine 5'-[gamma-thio]triphosphate, a hydrolysis-resistant analog of GTP. In the soluble fraction, such enhancement was not observed. Guanosine 5'-[beta-thio]diphosphate (2 mM), which irreversibly inactivates GTP-binding protein, blocked the enhancement in the particulate fraction. Membrane-binding phospholipase A2 activity of PMN would thus appear to be regulated directly by GTP-binding protein.

MeSH terms

  • Enzyme Activation
  • GTP-Binding Proteins / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Guanosine Diphosphate / analogs & derivatives
  • Guanosine Diphosphate / pharmacology
  • Humans
  • Membranes / enzymology
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology
  • Neutrophils / enzymology*
  • Phospholipases A / drug effects
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Subcellular Fractions / enzymology
  • Thionucleotides / pharmacology

Substances

  • Thionucleotides
  • Guanosine Diphosphate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • N-Formylmethionine Leucyl-Phenylalanine
  • guanosine 5'-O-(2-thiodiphosphate)
  • Phospholipases A
  • Phospholipases A2
  • GTP-Binding Proteins