Phosphatidic acid with medium-length fatty acyl chains synergistically stimulates phospholipase C with Ca2+ in rabbit platelets.
The mode of phospholipase C activation in platelet cells induced by didecanoyl (C10)-phosphatidic acid (PA) was investigated with washed rabbit platelets. The C10-PA dose-dependently induced aggregation and serotonin secretion, as well as increases in cytoplasmic free Ca2+ concentration and 1,2-diacylglycerol formation. None of these responses was evoked unless Ca2+ had been added to the platelet suspension. Furthermore, under the conditions of various intracellular Ca2+ concentrations which were set by treatment of the cells with ionomycin and Ca2+, C10-PA promoted 1,2-diacylglycerol formation only at the Ca2+ concentration of 300 nM or higher, whereas thrombin induced the formation even at 100 nM Ca2+. These results suggest that PA activates platelet phospholipase C in cooperation with Ca2+ and contributes to platelet activation through such an effect.
Hashizume
T
T
Department of Biochemistry, Kyoto Pharmaceutical University, Japan.
Sato
T
T
Fujii
T
T
D000818:Animals; D001792:Blood Platelets / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism*; D003652:Decanoic Acids; D004789:Enzyme Activation; D007700:Kinetics; D010712:Phosphatidic Acids / Q000737:chemistry / Q000502:physiology*; D015539:Platelet Activation; D011817:Rabbits; D010738:Type C Phospholipases / Q000378:metabolism*
D003652:Decanoic Acids; D010712:Phosphatidic Acids; C031071:decanoic acid; D010738:Type C Phospholipases; D002118:Calcium