The cytotoxic cell protease granzyme B initiates apoptosis in a cell-free system by proteolytic processing and activation of the ICE/CED-3 family protease, CPP32, via a novel two-step mechanism
The cytotoxic cell protease granzyme B initiates apoptosis in a cell-free system by proteolytic processing and activation of the ICE/CED-3 family protease, CPP32, via a novel two-step mechanism
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DOI：
10.1002/j.1460-2075.1996.tb00598.x
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发表时间：
1996-05-15
期刊：
影响因子：
11.4
通讯作者：
Green, DR
中科院分区：
文献类型：
--
作者：
Martin, SJ;AmaranteMendes, GP;Green, DR
细胞毒性淋巴细胞杀伤的主要机制涉及将含有穿孔素和许多蛋白酶的颗粒定向释放到靶细胞膜上。这些蛋白酶之一，颗粒酶B，对Asp残基具有不寻常的底物位点偏好，这是与新兴的白细胞介素-1 β-转化酶（ICE）/CED-3蛋白酶家族成员共有的性质，在此，我证明，当引入Jurkat无细胞提取物时，颗粒酶B足以快速再现细胞凋亡的所有关键特征，包括几种蛋白质底物的降解。颗粒酶B诱导的细胞凋亡被ICE/CED-3家族蛋白酶的四肽抑制剂CPP 32中和，尽管ICE的类似抑制剂没有作用，但发现颗粒酶B通过在CPP 32酶原的大小亚基之间切割，导致通过自催化步骤除去前结构域，将CPP 32而不是ICE转化成其活性形式。牛痘病毒蛋白CrmA，一种已知的ICE家族蛋白酶以及颗粒酶B的抑制剂，这些数据表明，在由颗粒酶B启动的凋亡过程中，CPP 32活化是关键事件。
The major mechanism of cytotoxic lymphocyte killing involves the directed release of granules containing perforin and a number of proteases onto the target cell membrane, One of these proteases, granzyme B, has an unusual substrate site preference for Asp residues, a property that it shares with members of the emerging interleukin-1 beta-converting enzyme (ICE)/CED-3 family of proteases, Here me show that granzyme B is sufficient to reproduce rapidly all of the key features of apoptosis, including the degradation of several protein substrates, when introduced into Jurkat cell-free extracts, Granzyme B-induced apoptosis was neutralized by a tetrapeptide inhibitor of the ICE/CED-3 family protease, CPP32, whereas a similar inhibitor of ICE had no effect, Granzyme B was found to convert CPP32, but not ICE, to its active form by cleaving between the large and small subunits of the CPP32 proenzyme, resulting in removal of the prodomain via an autocatalytic step, The cowpox virus protein CrmA, a known inhibitor of ICE family proteases as welI as granzyme B, inhibited granzyme B-mediated CPP32 processing and apoptosis, These data demonstrate that CPP32 activation is a key event during apoptosis initiated by granzyme B.