Bcl-XL interacts with Apaf-1 and inhibits Apaf-1-dependent caspase-9 activation
Bcl-XL interacts with Apaf-1 and inhibits Apaf-1-dependent caspase-9 activation
复制标题
DOI：
10.1073/pnas.95.8.4386
复制
发表时间：
1998-04-14
影响因子：
11.1
通讯作者：
Núñez, G
中科院分区：
文献类型：
--
作者：
Hu, YM;Benedict, MA;Núñez, G
最近的研究表明，秀丽隐杆线虫CED-4与死亡蛋白酶CED-3相互作用并促进其活化，并且这种活化被CED-9抑制。在这里，我们表明CED-4的哺乳动物同源物Apaf-1可以与哺乳动物细胞中的几种死亡蛋白酶，包括caspase-4，caspase-8，caspase-9和线虫CED-3相关联。与caspase-9的相互作用由Apaf-1的N-末端CED-4样结构域介导。Apaf-1的表达增强了caspase-9的杀伤活性，这需要Apaf-1的CED-4样结构域。此外，Apaf-1在体内促进caspase-9的加工和活化。Bcl-X-L是Bcl-2家族的抗凋亡成员，在哺乳动物细胞中与Apaf-1和caspase-9发生物理相互作用。Apaf-1与Bcl-X-L的结合是通过其CED-4样结构域和含有WD-40重复序列的C-末端结构域介导的。Bcl-X-L的表达抑制了Apaf-1与caspase-9在哺乳动物细胞中的结合。从大肠杆菌或昆虫细胞中纯化的重组Bcl-X-L能显著抑制Apaf-1依赖的caspase-9加工，而且不能抑制由组成型活性Apaf-1突变体介导的caspase-9加工，提示Bcl-X-L通过Apaf-1调节caspase-9。这些实验证明Bcl-X-L与半胱天冬酶-9和Apaf-1相关，并显示Bcl-X-L抑制由Apaf-1介导的半胱天冬酶-9的成熟，这是从线虫到人类进化保守的过程。
Recent studies indicate that Caenorhabditis elegans CED-4 interacts with and promotes the activation of the death protease CED-3, and that this activation is inhibited by CED-9, Here we show that a mammalian homolog of CED-4, Apaf-1, can associate with several death proteases, including caspase-4, caspase-8, caspase-9, and nematode CED-3 in mammalian cells. The interaction with caspase-9 was mediated by the N-terminal CED-4-like domain of Apaf-1. Expression of Apaf-1 enhanced the killing activity of caspase-9 that required the CED-4-like domain of Apaf-1. Furthermore, Apaf-1 promoted the processing and activation of caspase-9 in vivo. Bcl-X-L, an antiapoptotic member of the Bcl-2 family, was shown to physically interact with Apaf-1 and caspase-9 in mammalian cells. The association of Apaf-1 with Bcl-X-L was mediated through both its CED-4-like domain and the C-terminal domain containing WD-40 repeats. Expression of Bcl-X-L inhibited the association of Apaf-1 with caspase-9 in mammalian cells. Significantly, recombinant Bcl-X-L purified from Escherichia coli or insect cells inhibited Apaf-1-dependent processing of caspase-9, Furthermore, Bcl-X-L failed to inhibit caspase-9 processing mediated by a constitutively active Apaf-1 mutant, suggesting that Bcl-X-L regulates caspase-9 through Apaf-1. These experiments demonstrate that Bcl-X-L associates with caspase-9 and Apaf-1, and show that Bcl-X-L inhibits the maturation of caspase-9 mediated by Apaf-1, a process that is evolutionarily conserved from nematodes to humans.