Mixed lineage kinase domain-like is a key receptor interacting protein 3 downstream component of TNF-induced necrosis
Mixed lineage kinase domain-like is a key receptor interacting protein 3 downstream component of TNF-induced necrosis
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DOI：
10.1073/pnas.1200012109
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发表时间：
2012-04-03
影响因子：
11.1
通讯作者：
Liu, Zheng-Gang
中科院分区：
文献类型：
--
作者：
Zhao, Jie;Jitkaew, Siriporn;Liu, Zheng-Gang
肿瘤坏死因子是一种重要的炎性细胞因子，可诱导多种细胞反应，包括炎症、细胞增殖、细胞凋亡和坏死。已知受体相互作用蛋白(RIP)激酶RIP1和RIP3是肿瘤坏死的关键效应因子，但这两个RIP激酶是如何介导这一过程的鲜为人知，尽管ROS的产生和JNK的激活被认为是RIP激酶的两个下游事件。在这里，我们报告了混合谱系激酶结构域，MLKL，作为肿瘤坏死因子诱导的坏死的一个关键的RIP3下游成分。通过筛选人结肠腺癌HT-29细胞中的激酶/磷酸酶shRNA文库，我们发现MLKL的敲除可以阻断肿瘤坏死因子的诱导。我们的数据表明，MLKL在RIP1和RIP3下游发挥作用，并通过与RIP3的相互作用被招募到身体中。最后，我们发现在肿瘤坏死过程中，MLKL在ROS的产生和JNK的晚期激活中是必需的。然而，由于这两个事件并不涉及肿瘤坏死因子诱导的HT-29细胞的坏死，因此在肿瘤坏死因子诱导的坏死过程中MLKL的靶点仍然不明确。综上所述，我们的研究表明MLKL是肿瘤坏死因子诱导的坏死细胞死亡的关键的RIP3下游成分。
Tumor necrosis factor (TNF) is an important inflammatory cytokine and induces many cellular responses, including inflammation, cell proliferation, apoptosis, and necrosis. It is known that receptor interacting protein (RIP) kinases, RIP1 and RIP3, are key effectors of TNF-induced necrosis, but little is known about how these two RIP kinases mediate this process, although reactive oxygen species (ROS) generation and JNK activation have been suggested to be two downstream events of RIP kinases. Here we report the identification of mixed lineage kinase domain-like, MLKL, as a key RIP3 downstream component of TNF-induced necrosis. Through screening a kinase/phosphatase shRNA library in human colon adenocarcinoma HT-29 cells, we found that knockdown of MLKL blocked TNF-induced necrosis. Our data suggest that MLKL functions downstream of RIP1 and RIP3 and is recruited to the necrosome through its interaction with RIP3. Finally, we found that MLKL is required for the generation of ROS and the late-phase activation of JNK during TNF-induced necrosis. However, because these two events are not involved in TNF-induced necrosis in HT-29 cells, the target of MLKL during TNF-induced necrosis remains elusive. Taken together, our study suggests that MLKL is a key RIP3 downstream component of TNF-induced necrotic cell death.