Breakdown and synthesis of polyphosphoinositides in fMetLeuPhe-stimulated neutrophils.
The interconversions of the inositol-containing lipids (PI, PI-P and PI-P2) and their products (DG, inositol phosphates and PA) in human and rabbit neutrophils stimulated with fMetLeuPhe and PMA have been examined. PMA causes only the phosphorylation of PI to PI-P whereas fMetLeuPhe causes phosphorylation of both PI and PI-P yielding PI-P2 and the hydrolysis of all three lipids. While the predominant reaction is breakdown of PI to PA catalysed by phospholipase D, approx. 2% of PI is converted to polyphosphoinositides and then broken down by the phospholipase C route yielding inositol phosphates and DG. The latter reaction occurs without detectable lag and is a function of receptor occupancy. The amount of inositol trisphosphate thus formed would be sufficient to release Ca2+ from intracellular stores.
Cockcroft
S
S
Barrowman
M M
MM
Gomperts
B D
BD
D000818:Animals; D004075:Diglycerides / Q000097:blood; D006801:Humans; D006868:Hydrolysis; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000097:blood; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000097:blood*; D010766:Phosphorylation; D011817:Rabbits; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004075:Diglycerides; D010712:Phosphatidic Acids; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C037178:phosphatidylinositol 4-phosphate; D009240:N-Formylmethionine Leucyl-Phenylalanine; D013755:Tetradecanoylphorbol Acetate