Ariyoshi H, Shiba E, Sakon M, Kambayashi J, Yoshida K, Kawashima S, Mori T
Department of Surgery II, Osaka University School of Medicine, Japan.
Biochem Mol Biol Int. 1993 May;30(1):63-72.
Intracellular localization of calpain (calcium dependent cysteine proteinase) was studied in resting or activated human platelets. When stimulated with 2 U/ml thrombin, approximately 40% of total cellular calpain activity and 25% of antigen translocated mainly to the intracellular membrane fractions with autolytic activation. Translocation of calpain was completely abolished by the addition of EDTA to the sonication medium. However an endogenous calpain inhibitor (calpastatin) activity was not detected in the membrane fractions both in resting and in thrombin stimulated platelets. Translocation of calpain was also observed in the platelets stimulated with ionomycin, collagen or phorbor myristate acetate (PMA). These data suggest that cytosolic calpain reversibly translocates to the intracellular membranes during platelet activation without an interference by calpastatin.
在静息或激活的人血小板中研究了钙蛋白酶（钙依赖性半胱氨酸蛋白酶）的细胞内定位。用2 U/ml凝血酶刺激时，约40%的总细胞钙蛋白酶活性和25%的抗原主要通过自溶激活转移至细胞内膜部分。向超声处理介质中添加乙二胺四乙酸（EDTA）可完全消除钙蛋白酶的转移。然而，在静息和凝血酶刺激的血小板的膜部分均未检测到内源性钙蛋白酶抑制剂（钙蛋白酶抑制蛋白）活性。在用离子霉素、胶原或佛波醇肉豆蔻酸酯乙酸酯（PMA）刺激的血小板中也观察到了钙蛋白酶的转移。这些数据表明，在血小板激活过程中，胞质钙蛋白酶可逆地转移至细胞内膜，且不受钙蛋白酶抑制蛋白的干扰。
