Cytochrome c activation of CPP32-like proteolysis plays a critical role in a Xenopus cell-free apoptosis system
Cytochrome c activation of CPP32-like proteolysis plays a critical role in a Xenopus cell-free apoptosis system
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DOI：
10.1093/emboj/16.15.4639
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发表时间：
1997-08-01
期刊：
影响因子：
11.4
通讯作者：
Newmeyer, DD
中科院分区：
文献类型：
--
作者：
Kluck, RM;Martin, SJ;Newmeyer, DD
在基于爪蟾卵提取物的无细胞系统中，Bcl-2通过阻止线粒体释放细胞色素c来阻断凋亡活性。我们现在详细描述细胞色素c在该系统中的关键作用，当与细胞质一起孵育时，线粒体部分释放细胞色素c，细胞色素c反过来诱导类似于半胱天冬酶-3（CPP 32）的蛋白酶的活化，导致下游凋亡事件，包括胞衬蛋白和核纤层蛋白B-1的切割，CPP 32样蛋白酶活性在该系统中起重要作用，作为半胱天冬酶抑制剂，Ac-DEVD-CHO强烈抑制胞衬蛋白和核纤层蛋白B-1的切割，以及核形态学的变化，来自各种脊椎动物物种的细胞色素c制剂，但不是来自酿酒酵母的，能够引发细胞凋亡的所有迹象，细胞色素c本身不能处理CPP 32的前体形式;细胞色素c的促凋亡功能不需要细胞色素c的电子传递活性，因为Cu-和Zn-取代的细胞色素c具有强的促凋亡活性，尽管是无氧化还原活性的。然而，该活性需要分子的某些结构特征。因此，在非洲爪蟾无细胞系统中，细胞色素c的细胞溶质依赖性线粒体释放通过未知的细胞溶质因子激活CPP 32样半胱天冬酶诱导细胞凋亡。
In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system, The mitochondrial fraction, when incubated with cytosol, releases cytochrome c, Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of fodrin and lamin B-1, CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited fodrin and lamin B-1 cleavage, as well as nuclear morphology changes, Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis, Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required, The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu-and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive, However, certain structural features of the molecule were required for this activity, Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.