TRAF-interacting protein with forkhead-associated domain (TIFA) transduces DNA damage-induced activation of NF-B
TRAF-interacting protein with forkhead-associated domain (TIFA) transduces DNA damage-induced activation of NF-B
复制标题
具有叉头相关结构域 (TIFA) 的 TRAF 相互作用蛋白可转导 DNA 损伤 — 诱导 NF-κB 激活
DOI：
10.1074/jbc.ra117.001684
复制
发表时间：
2018-05-11
影响因子：
4.8
通讯作者：
Zhang, Yu
中科院分区：
文献类型：
--
作者：
Fu, Jingxuan;Huang, Daoyuan;Zhang, Yu
DNA损伤诱导的核因子-B活化和炎性细胞因子的分泌在肿瘤的发生和细胞衰老过程中起着重要作用。然而，其潜在的机制，特别是连接核DNA损伤信号和细胞质核因子-B激活的初始感应器和转导器仍然不完全清楚。在这里，我们报道了TRAF相互作用蛋白与叉头相关结构域(TIFA)，一个已建立的核因子-B激活剂，在胞浆中，意外地在遗传毒性应激后表现出核转位和在受损染色质上的堆积。因此，我们还发现，在TIFA过表达的细胞中，DNA损伤诱导的转录激活和由此产生的经典核因子-B靶标的分泌，包括白介素6和白介素8，与对照细胞相比大大增强。从机制上讲，DNA损伤诱导TIFA苏氨酸9(pThr-9)磷酸化，这种涉及pThr结合叉头相关结构域的磷酸化事件对于其在受损染色质上的浓缩和随后的NF-B激活是至关重要的。此外，TIFA与其伴侣蛋白E3连接酶肿瘤坏死因子受体相关因子2(TRAF2)一起，通过刺激核因子-B必需调节物(NEMO)的泛素化来传递DNA损伤信号，而NEMO的泛素化、磷酸化和泛素化是核因子-B应答DNA损伤的关键。一致地，TRAF2基因敲除抑制了基因毒性应激下TIFA过度表达增强的Nemo泛素化，而不可磷酸化的Thr-9突变的TIFA变体对Nemo多泛素化只有很小的影响。最后，与DNA损伤相关的分泌衰老屏障抗癌模型一致，异位表达TIFA限制了多发性骨髓瘤癌细胞的增殖。综上所述，我们的结果表明，TIFA在DNA损伤诱导的核因子-B激活过程中起着关键的转导作用。
DNA damage-induced NF-B activation and the secretion of inflammatory cytokines play crucial roles in carcinogenesis and cellular senescence. However, the underlying mechanisms, especially the initial sensors and transducers connecting the nuclear DNA damage signal with cytoplasmic NF-B activation remain incompletely understood. Here, we report that TRAF-interacting protein with forkhead-associated domain (TIFA), an established NF-B activator in the cytosol, unexpectedly exhibited nuclear translocation and accumulation on damaged chromatin following genotoxic stress. Accordingly, we also found that DNA damage-induced transcriptional activation and the resulting secretion of classic NF-B targets, including interleukin (IL)-6 and IL-8, was greatly enhanced in TIFA-overexpressing cells compared with control cells. Mechanistically, DNA damage-induced TIFA phosphorylation at threonine 9 (pThr-9), and this phosphorylation event, involving the pThr-binding forkhead-associated domain, was crucial for its enrichment on damaged chromatin and subsequent NF-B activation. Moreover, in conjunction with its partner protein, the E3 ligase TNF receptor-associated factor 2 (TRAF2), TIFA relayed the DNA damage signals by stimulating ubiquitination of NF-B essential modulator (NEMO), whose sumoylation, phosphorylation, and ubiquitination were critical for NF-B's response to DNA damage. Consistently, TRAF2 knockdown suppressed TIFA overexpression-enhanced NEMO ubiquitination under genotoxic stress, and a unphosphorylatable Thr-9-mutated TIFA variant had only minor effects on NEMO poly-ubiquitination. Finally, in agreement with the model of DNA damage-associated secretory senescence barrier against carcinogenesis, ectopic TIFA expression limited proliferation of multiple myeloma cancer cells. In conclusion our results indicate that TIFA functions as a key transducer in DNA damage-induced NF-B activation.