Racaud-Sultan C, Mauco G, Guinebault C, Plantavid M, Payrastre B, Breton M, Chap H
INSERM U 326, Phospholipides Membranaires, Signalisation Cellulaire et Lipoprotéines, Hôpital Purpan, Toulouse, France.
FEBS Lett. 1993 Sep 20;330(3):347-51. doi: 10.1016/0014-5793(93)80902-7.
When platelets are stimulated by thrombin they immediately undergo inositol lipid hydrolysis via phospholipase C activation. However, subsequently an increased production of phosphatidylinositol 4,5-bisphosphate is observed. Phospholipases C were inhibited by lowering the cytoplasmic free calcium concentration by preincubation with Quin-2-tetra(acetoxymethyl) ester. Aggregation and secretion were also totally suppressed. Under these conditions we observed an increased labeling of phosphatidylinositol 4,5-bisphosphate, indicating a stimulation of inositol lipid kinases, independent of lipid hydrolysis by phospholipase C. Conversely the production of phosphatidylinositol 3,4-bisphosphate was totally abolished. These results suggest a different regulation of the kinases/phosphatases responsible for the production of phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4-bisphosphate.
当血小板受到凝血酶刺激时，它们会通过磷脂酶C的激活立即发生肌醇脂质水解。然而，随后观察到磷脂酰肌醇4,5-二磷酸的产量增加。通过与喹啉-2-四（乙酰氧基甲基）酯预孵育来降低细胞质游离钙浓度，从而抑制磷脂酶C。聚集和分泌也被完全抑制。在这些条件下，我们观察到磷脂酰肌醇4,5-二磷酸的标记增加，表明肌醇脂质激酶受到刺激，这与磷脂酶C的脂质水解无关。相反，磷脂酰肌醇3,4-二磷酸的产生则完全被消除。这些结果表明，负责磷脂酰肌醇4,5-二磷酸和磷脂酰肌醇3,4-二磷酸产生的激酶/磷酸酶受到不同的调节。
