Molecular ordering of the Fas-apoptotic pathway: The Fas/APO-1 protease Mch5 is a CrmA-inhibitable protease that activates multiple Ced-3/ICE-like cysteine proteases
Molecular ordering of the Fas-apoptotic pathway: The Fas/APO-1 protease Mch5 is a CrmA-inhibitable protease that activates multiple Ced-3/ICE-like cysteine proteases
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DOI：
10.1073/pnas.93.25.14486
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发表时间：
1996-12-10
影响因子：
11.1
通讯作者：
Alnemri, ES
中科院分区：
文献类型：
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作者：
Srinivasula, SM;Ahmad, M;Alnemri, ES
Fas/APO-1 受体相关半胱氨酸蛋白酶 Mch5 (MACH/FLICE) 被认为是在 Fas 受体连接后激活蛋白酶级联的酶，导致细胞死亡。 Fas 凋亡途径被牛痘丝氨酸蛋白酶抑制剂 CrmA 有效抑制，表明 Mch5 可能是该丝氨酸蛋白酶抑制剂的靶标。 proMch5 的细菌表达产生了由两个亚基组成的成熟酶，这两个亚基是通过在 Asp-227、Asp-233、Asp-391 和 Asp-401 处加工而衍生自前体酶原。我们证明重组 Mch5 能够处理/激活所有已知的 ICE/Ced-3 样半胱氨酸蛋白酶，并被 CrmA 有效抑制。这与 Mch4（第二种 FADD 相关半胱氨酸蛋白酶，也能够处理/激活所有已知的 ICE/Ced-3 样半胱氨酸蛋白酶）的观察结果形成鲜明对比，但 CrmA 的抑制效果很差。这些数据表明，Mch5 是最上游的蛋白酶，它接收来自 Fas 受体的激活信号，启动凋亡蛋白酶级联，从而导致 ICE 样蛋白酶（TX、ICE 和 ICE-relIII）、Ced-3 样蛋白酶（CPP32、Mch2、Mch3、Mch4 和 Mch6）和 ICH-1 蛋白酶的激活。另一方面，Mch4 可能是第二个上游蛋白酶，负责在 CrmA 不敏感的细胞凋亡途径中激活相同的蛋白酶级联。
The Fas/APO-1-receptor associated cysteine protease Mch5 (MACH/FLICE) is believed to be the enzyme responsible for activating a protease cascade after Fas-receptor ligation, leading to cell death. The Fas-apoptotic pathway is potently inhibited by the cowpox serpin CrmA, suggesting that Mch5 could be the target of this serpin. Bacterial expression of proMch5 generated a mature enzyme composed of two subunits, which are derived from the precursor proenzyme by processing at Asp-227, Asp-233, Asp-391, and Asp-401. We demonstrate that recombinant Mch5 is able to process/activate all known ICE/Ced-3-like cysteine proteases and is potently inhibited by CrmA. This contrasts with the observation that Mch4, the second FADD-related cysteine protease that is also able to process/activate all known ICE/Ced-3-like cysteine proteases, is poorly inhibited by CrmA. These data suggest that Mch5 is the most upstream protease that receives the activation signal from the Fas-receptor to initiate the apoptotic protease cascade that leads to activation of ICE-like proteases (TX, ICE, and ICE-relIII), Ced-3-like proteases (CPP32, Mch2, Mch3, Mch4, and Mch6), and the ICH-1 protease. On the other hand, Mch4 could be a second upstream protease that is responsible for activation of the same protease cascade in CrmA-insensitive apoptotic pathways.