Shimizu S, Eguchi Y, Kamiike W, Matsuda H, Tsujimoto Y
First Department of Surgery, Osaka University Medical School, Japan.
Oncogene. 1996 Jun 6;12(11):2251-7.
The Bcl-2 family and the ICE family of cysteine proteases play important roles in regulating cell death. We show here that induction of cell death by a Ca2+ ionophore or hypoxia results in increased levels and activity of active ICE(-like) proteases and the subsequent activation of CPP32/Yama(-like) proteases, and that inhibition of these protease activities reduces the extent of cell death. Overexpression of the anti-apoptotic proteins Bcl-2 or Bcl-xL inhibits the cell death and the activation of ICE(-like) and CPP32/Yama(-like) proteases, indicating that Bcl-2 and Bcl-xL act upstream of these proteases. We also show that specific inhibition of ICE(-like) proteases in vivo prevents activation of CPP32/Yama(-like) proteases, whereas inhibition of CPP32/Yama(-like) proteases does not prevent activation of ICE(-like) proteases, suggesting the existence of a protease cascade in vivo that requires ICE(-like) proteases for activation of CPP32/Yama(-like) proteases. Induction of necrotic cell death by KCN also induces activation of ICE(-like) proteases but not of CPP32/Yama(-like) proteases, and Bcl-2 and Bcl-xL inhibit the activation and the cell death, suggesting that the functional site of Bcl-2 and Bcl-xL is also upstream of ICE(-like) proteases in at least some forms of necrosis.
Bcl-2家族和半胱氨酸蛋白酶的ICE家族在调节细胞死亡过程中发挥着重要作用。我们在此表明，钙离子载体或缺氧诱导细胞死亡会导致活性ICE（类）蛋白酶的水平和活性增加，随后激活CPP32/Yama（类）蛋白酶，并且抑制这些蛋白酶活性会降低细胞死亡的程度。抗凋亡蛋白Bcl-2或Bcl-xL的过表达会抑制细胞死亡以及ICE（类）和CPP32/Yama（类）蛋白酶的激活，这表明Bcl-2和Bcl-xL在这些蛋白酶的上游起作用。我们还表明，体内对ICE（类）蛋白酶的特异性抑制可防止CPP32/Yama（类）蛋白酶的激活，而抑制CPP32/Yama（类）蛋白酶并不能防止ICE（类）蛋白酶的激活，这表明体内存在一种蛋白酶级联反应，该反应需要ICE（类）蛋白酶来激活CPP32/Yama（类）蛋白酶。KCN诱导的坏死性细胞死亡也会诱导ICE（类）蛋白酶的激活，但不会诱导CPP32/Yama（类）蛋白酶的激活，并且Bcl-2和Bcl-xL会抑制这种激活和细胞死亡，这表明在至少某些形式的坏死中，Bcl-2和Bcl-xL的功能位点也在ICE（类）蛋白酶的上游。
