The mitochondrial serine protease HtrA2/Omi cleaves RIP1 during apoptosis of Ba/F3 cells induced by growth factor withdrawal
The mitochondrial serine protease HtrA2/Omi cleaves RIP1 during apoptosis of Ba/F3 cells induced by growth factor withdrawal
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DOI：
10.1038/cr.2010.18
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发表时间：
2010-04-01
期刊：
影响因子：
44.1
通讯作者：
Vandenabeele, Peter
中科院分区：
文献类型：
--
作者：
Vande Walle, Lieselotte;Wirawan, Ellen;Vandenabeele, Peter
白介素3(IL-3)剥夺小鼠前B细胞系BA/F3诱导的细胞死亡被B细胞淋巴瘤2(Bcl2)过表达所消除，但不受泛半胱氨酸酶抑制剂carbobenzoxy-valyl-analylaspartyl-[O-methyl]-fluoromethylketone(zVAD-fmk)的影响。停用IL-3可导致受体相互作用蛋白(RIP)1裂解成30 kDa和25 kDa的C末端片段，而zVAD-fmk只能阻止导致前者的裂解。SiRNA实验证明，这一25 kDa片段的产生是由于Bcl-2调控线粒体丝氨酸蛋白酶高温需要蛋白A2(HtrA2)/Omi的释放。因此，重组HtrA2/Omi在体外有效地切割小鼠RIP1，产生与在IL-3剥夺的BA/F3细胞中观察到的片段相匹配的片段。小鼠RIP1的HtrA2/Omi裂解位点被定位到中间结构域，相应的N-末端和C-末端片段激活核因子-kappaB、c-jun N-末端激酶和p38丝裂原激活的蛋白激酶的能力受到损害。有趣的是，在zVAD-fmk存在的情况下，HtrA2/Omi的敲除对IL-3戒断诱导的死亡具有保护作用，表明HtrA2/Omi通过裂解RIP1在生长因子戒断过程中caspase非依赖性细胞死亡中发挥作用。
Interleukin-3 (IL-3) deprivation of the mouse pro-B cell line Ba/F3 induces cell death that is abrogated by B-cell lymphoma 2 (Bcl-2) overexpression, but remains unaffected by the pan-caspase inhibitor carbobenzoxy-valyl-analylaspartyl-[O-methyl]-fluoromethylketone (zVAD-fmk). IL-3 withdrawal causes receptor-interacting protein (RIP) 1 cleavage into C-terminal fragments of 30 and 25 kDa, and only cleavage leading to the former was prevented by zVAD-fmk. siRNA experiments demonstrated that generation of the 25-kDa fragment was due to a Bcl-2-modulated release of the mitochondrial serine protease high temperature requirement protein A2 (HtrA2)/Omi. Accordingly, recombinant HtrA2/Omi efficiently cleaved mouse RIP1 in vitro, generating fragments matching those observed in IL-3-deprived Ba/F3 cells. The HtrA2/Omi cleavage site in mouse RIP1 was mapped to the intermediate domain and the corresponding N- and C-terminal fragments were impaired in their ability to activate nuclear factor-kappa B, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. Interestingly, knockdown of HtrA2/Omi afforded protection against IL-3 withdrawal-induced death in the presence of zVAD-fmk, demonstrating a role for HtrA2/Omi in caspase-independent cell death during growth factor withdrawal by cleaving RIP1.