c-IAP1 and c-IAP2 are critical mediators of tumor necrosis factor α (TNFα)-induced NF-κB activation
c-IAP1 and c-IAP2 are critical mediators of tumor necrosis factor α (TNFα)-induced NF-κB activation
复制标题
DOI：
10.1074/jbc.c800128200
复制
发表时间：
2008-09-05
影响因子：
4.8
通讯作者：
Vucic, Domagoj
中科院分区：
文献类型：
--
作者：
Varfolomeev, Eugene;Goncharov, Tatiana;Vucic, Domagoj
凋亡抑制剂 (IAP) 蛋白是在病毒和后生动物中发现的抗凋亡调节因子家族。 c-IAP1 和 c-IAP2 被招募到肿瘤坏死因子受体 1 (TNFR1) 相关复合物中，在那里它们可以调节受体介导的信号传导。 c-IAP1 和 c-IAP2 均与 TNF α 刺激的 NF-κ B 激活有关。然而，小鼠中单独的 c-IAP1 和 c-IAP2 基因敲除并没有揭示 TNF 信号通路的变化，并且 c-IAP 联合缺陷的表型尚未有报道。在这里，我们研究了 c-IAP1 和 c-IAP2 在 TNF α 刺激的 NF-κ B 激活中的作用。我们证明，在两种 c-IAP 蛋白不存在的情况下，TNF α 诱导的 NF-κ B 激活会严重减弱。此外，c-IAP1 和 c-IAP2 的联合缺失使细胞对 TNF α 诱导的细胞死亡敏感。使用 c-IAP1 基因消除的细胞或使用 IAP 拮抗剂消除 c-IAP 蛋白的细胞，我们发现在不存在 c-IAP 的情况下，TNF α 诱导的 RIP1 泛素化被消除。此外，我们在体外用纯化的成分重建了泛素化过程，并证明 c-IAP1 与泛素结合酶 (E2) UbcH5a 协同作用，介导 RIP1 上 Lys-63 连接链的聚合。因此，c-IAP1 和 c-IAP2 是 TNF α 刺激的 RIP1 泛素化和 NF-κ B 激活所必需的。
The inhibitor of apoptosis (IAP) proteins are a family of antiapoptotic regulators found in viruses and metazoans. c-IAP1 and c-IAP2 are recruited to tumor necrosis factor receptor 1 (TNFR1)-associated complexes where they can regulate receptor-mediated signaling. Both c-IAP1 and c-IAP2 have been implicated in TNF alpha-stimulated NF-kappa B activation. However, individual c-IAP1 and c-IAP2 gene knock-outs in mice did not reveal changes in TNF signaling pathways, and the phenotype of a combined deficiency of c-IAPs has yet to be reported. Here we investigate the role of c-IAP1 and c-IAP2 in TNF alpha-stimulated activation of NF-kappa B. We demonstrate that TNF alpha-induced NF-kappa B activation is severely diminished in the absence of both c-IAP proteins. In addition, combined absence of c-IAP1 and c-IAP2 rendered cells sensitive to TNF alpha-induced cell death. Using cells with genetic ablation of c-IAP1 or cells where the c-IAP proteins were eliminated using IAP antagonists, we show that TNF alpha-induced RIP1 ubiquitination is abrogated in the absence of c-IAPs. Furthermore, we reconstitute the ubiquitination process with purified components in vitro and demonstrate that c-IAP1, in collaboration with the ubiquitin conjugating enzyme (E2) enzyme UbcH5a, mediates polymerization of Lys-63-linked chains on RIP1. Therefore, c-IAP1 and c-IAP2 are required for TNF alpha-stimulated RIP1 ubiquitination and NF-kappa B activation.