Leupeptin does not affect the normal signal transduction mechanism in platelets

FEBS Letters

Herreros, B.¹  Sanchez, A.¹  Alonso, M.T.¹ 

[1] Departamento de Bioquimica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid 47005, Valladolid, Spain

关键词: Leupeptin;    Ca2+;    intracellular;    pH;    intracellular;    Thromboxane B2;    (Platelet);    TPA;    phorbol 12-myristate 13-acetate;    BCECF;    2;    7-biscarboxyethyl-5(6)-carboxyfluorescein;    BSA;    bovine serum albumin;    ACD;    acid-citrate dextrose;    DG;    diacylglycerol;    PIP2;    phosphatidylinositol 4;    5-bisphosphate;    IP3;    inositol 1;    4;    5-trisphosphate;    PLC;    phospholipase C;    PLA2;    phospholipase A2;    TXB2;    thromboxane B2;   

DOI  :  10.1016/0014-5793(89)80573-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Calpains are Ca²⁺-dependent serine proteases that can regulate protein kinase C-mediated cellular events by cleaving the membrane-bound native enzyme to yield an activated cytosolic fragment. Inhibition of calpain by leupeptin may cause enhancement or inhibition of cellular functions depending on the nature of the protein kinase C reaction involved. We have studied the effects of leupeptin on platelet responses (aggregation, secretion, thromboxane B₂ formation and intracellular Ca²⁺ and pH changes) induced by either thrombin, collagen or phorbol 12-myristate 13-acetate (TPA), which are known to activate protein kinase C by different mechanisms. Only thrombin-induced responses were inhibited by leupeptin. This suggests that the inhibitory effect of leupeptin is not due to antagonism of calpain in this system, but to direct interference with the proteolytic effect of thrombin.

【 授权许可】

Unknown