Death receptor recruitment of endogenous caspase-10 and apoptosis initiation in the absence of caspase-8.
Death receptor recruitment of endogenous caspase-10 and apoptosis initiation in the absence of caspase-8.
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DOI：
10.1074/jbc.m105102200
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发表时间：
2001-12-07
影响因子：
4.8
通讯作者：
Ashkenazi, A
中科院分区：
文献类型：
--
作者：
Kischkel, FC;Lawrence, DA;Ashkenazi, A
Caspase-8被认为在死亡受体引发的细胞凋亡中起着强制性的作用，但其结构相对物Caspase-10的作用仍然存在争议。虽然早期的证据表明caspase-10参与了CD 95 L和Apo 2L/TRAIL的凋亡信号传导，但最近的研究表明，即使在大量caspase-10存在的情况下，这些死亡受体配体也会将caspase-8而不是caspase-10募集到其死亡诱导信号复合物（DISC）中。我们表征了一系列caspase-10特异性抗体，并发现某些市售抗体与HSP 60交叉反应，为以前的结果提供了新的线索。大多数的55个肺癌和乳腺癌细胞系表达mRNA的caspase-8和-10;然而，免疫印迹分析显示，caspase-10蛋白表达更频繁地缺席比caspase-8，这表明可能的选择性压力对caspase-10的生产在癌细胞。在非转染细胞表达caspase，CD 95 L和Apo 2L/TRAIL招募内源性caspase-10以及caspase-8到他们的DISC，其中两种酶的蛋白水解处理具有相似的动力学。半胱天冬酶-10的募集需要衔接子FADD/Mort 1，而半胱天冬酶-10的体外裂解需要DISC组装，这与细胞凋亡引发剂的加工一致。仅表达一种半胱天冬酶的细胞经历配体诱导的细胞凋亡，表明每种半胱天冬酶可以独立于其它半胱天冬酶启动细胞凋亡。因此，凋亡信号的死亡受体不仅涉及caspase-8，但也caspase-10，这两个caspase可能有同样重要的作用，在细胞凋亡的启动。
Caspase-8 is believed to play an obligatory role in apoptosis initiation by death receptors, but the role of its structural relative, caspase-10, remains controversial. Although earlier evidence implicated caspase-10 in apoptosis signaling by CD95L and Apo2L/TRAIL, recent studies indicated that these death receptor ligands recruit caspase-8 but not caspase-10 to their death-inducing signaling complex (DISC) even in presence of abundant caspase-10. We characterized a series of caspase-10-specific antibodies and found that certain commercially available antibodies cross-react with HSP60, shedding new light on previous results. The majority of 55 lung and breast carcinoma cell lines expressed mRNA for both caspase-8 and -10; however, immunoblot analysis revealed that caspase-10 protein expression was more frequently absent than that of caspase-8, suggesting a possible selective pressure against caspase-10 production in cancer cells. In nontransfected cells expressing both caspases, CD95L and Apo2L/TRAIL recruited endogenous caspase-10 as well as caspase-8 to their DISC, where both enzymes were proteolytically processed with similar kinetics. Caspase-10 recruitment required the adaptor FADD/ Mort1, and caspase-10 cleavage in vitro required DISC assembly, consistent with the processing of an apoptosis initiator. Cells expressing only one of the caspases underwent ligand-induced apoptosis, indicating that each caspase can initiate apoptosis independently of the other. Thus, apoptosis signaling by death receptors involves not only caspase-8 but also caspase-10, and both caspases may have equally important roles in apoptosis initiation.