Allantopyrone A is a fungal metabolite that uniquely possesses two α,β-unsaturated carbonyl moieties. We recently reported that allantopyrone A inhibited the nuclear factor-κB (NF-κB) signaling pathway induced by tumor necrosis factor (TNF)-α in human lung carcinoma A549 cells. In the present study, the mechanism by which allantopyrone A inhibits the TNF-α-induced signaling pathway was investigated in more detail. Allantopyrone A blocked extensive modifications to receptor-interacting protein 1 (RIP1) in the TNF receptor 1 (TNF-R1) complex. Allantopyrone A augmented the high-MW bands of TNF-R1, TNF receptor-associated factor 2, RIP1, the NF-κB subunit RelA and inhibitor of NF-κB kinase β in A549 cells, suggesting that it binds to and promotes the crosslinking of these proteins. The extracellular cysteine-rich domains of TNF-R1 were crosslinked by allantopyrone A more preferentially than its intracellular portion. The present results demonstrate that allantopyrone A interferes with multiple components of the TNF-R1 complex and blocks RIP1 modifications in the TNF-α-induced NF-κB signaling pathway.

中文翻译：

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尿嘧啶A干扰TNF受体1复合物的多个成分并阻断TNF- α诱导的信号通路中的RIP1修饰

尿嘧啶酮A是一种真菌代谢产物，其独特地具有两个α，β-不饱和羰基部分。最近，我们报道了尿嘧啶酮A抑制人肺癌A549细胞中由肿瘤坏死因子（TNF）-α诱导的核因子-κB（NF-κB）信号传导途径。在本研究中，尿嘧啶酮A抑制TNF- α的机制-诱导的信号传导途径进行了更详细的研究。尿嘧啶A阻断了TNF受体1（TNF-R1）复合物中受体相互作用蛋白1（RIP1）的广泛修饰。尿嘧啶酮A增强了A549细胞中TNF-R1，TNF受体相关因子2，RIP1，NF-κB亚基RelA和NF-κB激酶β抑制剂的高分子量谱带，表明它与A549细胞结合并促进其交联这些蛋白质。TNF-R1的富含胞外半胱氨酸的结构域比其胞内部分更优先地被尿嘧啶A交联。目前的结果表明，Allantopyrone A干扰TNF-R1复合物的多种成分，并阻断TNF- α诱导的NF-κB信号通路中的RIP1修饰。