Polyphosphoinositide turnover in rat mast cells stimulated by antigen: rapid and preferential breakdown of phosphatidylinositol 4-phosphate (DPI).
The effect of antigen on the metabolism of polyphosphoinositides was investigated in sensitized rat peritoneal mast cells. Addition of antigen to rat peritoneal mast cells prelabelled with [3H]arachidonic acid resulted in a very rapid decrease in the level of phosphatidylinositol 4-phosphate (DPI) within 5 sec, which appeared to precede the breakdown of phosphatidylinositol (PI), while there was no significant decline of PI 4,5-bisphosphate (TPI). The reduced levels of these phosphoinositides returned almost to control or even slightly higher values by 300 sec in parallel with the antigen-stimulated [32P]phosphate incorporation into these lipids. This early and transient disappearance in DPI prior to that in PI was also observed in [3H]glycerol-prelabelled cells. These data suggest that DPI degradation upon stimulation by antigen in mast cells may be an initial step in the histamine release process.
D000818:Animals; D000941:Antigens; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D007700:Kinetics; D008407:Mast Cells / Q000276:immunology / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium
D000941:Antigens; D001095:Arachidonic Acids; D010710:Phosphates; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; C037178:phosphatidylinositol 4-phosphate; D014316:Tritium; D016718:Arachidonic Acid; D005990:Glycerol