Identification of Omi/HtrA-2 as a mitochondrial apoptotic serine protease that disrupts inhibitor of apoptosis protein-caspase interaction
Identification of Omi/HtrA-2 as a mitochondrial apoptotic serine protease that disrupts inhibitor of apoptosis protein-caspase interaction
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DOI：
10.1074/jbc.m109721200
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发表时间：
2002-01-04
影响因子：
4.8
通讯作者：
Alnemri, ES
中科院分区：
文献类型：
--
作者：
Hegde, R;Srinivasula, SM;Alnemri, ES
为了鉴定与人XIAP的杆状病毒抑制蛋白(IAP)重复序列3(BIR3)结构域上的Smac和caspase-9结合口袋结合的人蛋白，我们使用BIR3作为亲和试剂，然后用BIR3结合多肽AVPIA进行洗脱，并进行微测序和质谱分析。成熟的丝氨酸蛋白酶Omi(也称为HtrA2)是一种线粒体BIR3直接结合蛋白和caspase激活剂。与成熟的Smac(也称为Diablo)一样，成熟的Omi在其N端含有一个保守的LAP结合基序(AVP)，当其N端的线粒体靶向序列被输入线粒体时，该基序就会暴露出来。成熟的OMi与成熟的Smac一起从线粒体释放到胞浆中，在细胞凋亡过程中线粒体膜被破坏。最后，成熟的Omi可以通过其蛋白酶活性以不依赖于caspase的方式诱导人类细胞凋亡，并通过破坏caspase-LAP相互作用以依赖于caspase的方式诱导细胞凋亡。我们的结果为线粒体丝氨酸蛋白酶参与细胞凋亡提供了明确的证据，强调了线粒体在细胞死亡中的关键作用。
To identify human proteins that bind to the Smac and caspase-9 binding pocket on the baculoviral inhibitor of apoptosis protein (IAP) repeat 3 (BIR3) domain of human XIAP, we used BIR3 as an affinity reagent, followed by elution with the BIR3 binding peptide AVPIA microsequencing, and mass spectrometry. The mature serine protease Omi (also known as HtrA2) was identified as a mitochondrial direct BIR3-binding protein and a caspase activator. Like mature Smac (also known as Diablo), mature Omi contains a conserved LAP-binding motif (AVPS) at its N terminus, which is exposed after processing of its N-terminal mitochondrial targeting sequence upon import into the mitochondria. Mature Omi is released together with mature Smac from the mitochondria into the cytosol upon disruption of the outer mitochondrial membrane during apoptosis. Finally, mature Omi can induce apoptosis in human cells in a caspase-independent manner through its protease activity and in a caspase-dependent manner via its ability to disrupt caspase-LAP interaction. Our results provide clear evidence for the involvement of a mitochondrial serine protease in the apoptotic pathway, emphasizing the critical role of the mitochondria in cell death.