Activation of phospholipase C in thrombin‐stimulated platelets does not depend on cytoplasmic free calcium concentration

FEBS Letters

Chap, Hugues¹  Simon, Marie-Françoise¹  Douste-Blazy, Louis¹ 

[1] INSERM Unité 101, Biochimie des Lipides, Hôpital Purpan, 31059 Toulouse, France

关键词: Platelet activation;    Thrombin;    Phospholipase C;    Inositol phospholipid;    Calcium;    Fluorescent indicator;    PI;    phosphatidylinositol;    PI-P;    phosphatidylinositol 4-phosphate;    PI-P2;    phosphatidylinositol 4;    5-bisphosphate;    DG;    diglyceride;    PA;    phosphatidic acid;    PLC;    phospholipase C;    [Ca2+]i;    cytoplasmic free calcium concentration;    [Ca2+]e;    external free calcium concentration;    PRP;    platelet-rich plasma;    AA;    arachidonic acid;   

DOI  :  10.1016/0014-5793(84)81365-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Human platelets loaded with the fluorescent Ca²⁺ indicator quin2 and with different radioactive compounds including [³H]serotonin, [¹⁴C]arachidonic acid (AA) and [³²P]orthophosphate were stimulated by thrombin under conditions producing secretion. In the absence of external Ca²⁺ (Ca²⁺ _e), cytoplasmic free [Ca²⁺], [Ca²⁺]_i, increased to 340 nM, against 1685 nM at 1 mM [Ca²⁺]_e. In both cases, diglyceride and phosphatidic acid production proceeded at the same rate, whereas AA release was inhibited at low [Ca²⁺]_i. It is concluded that, at variance with phospholipase A₂, phospholipase C activation does not depend on [Ca²⁺]_i. These results give further support to the hypothesis of a Ca²⁺-independent pathway of cell activation involving phospholipase C and protein kinase C.

【 授权许可】

Unknown