Riboflavin kinase couples TNF receptor 1 to NADPH oxidase
Riboflavin kinase couples TNF receptor 1 to NADPH oxidase
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DOI：
10.1038/nature08206
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发表时间：
2009-08-27
期刊：
影响因子：
64.8
通讯作者：
Kroenke, Martin
中科院分区：
文献类型：
--
作者：
Yazdanpanah, Benjamin;Wiegmann, Katja;Kroenke, Martin
NADPH氧化酶产生的活性氧（ROS）作为与先天免疫和各种细胞反应相关的防御和信号分子发挥作用（1，2）。响应于质膜受体活化的NADPH氧化酶的活化取决于胞质氧化酶亚基的磷酸化、它们向膜的转运以及所有NADPH氧化酶组分的组装（3）。肿瘤坏死因子（TNF）是ROS产生的主要刺激物，但TNF激活NADPH氧化酶的分子机制知之甚少。在这里，我们确定核黄素激酶（RFK，以前称为黄素激酶（4））作为一种以前未被识别的TNF-受体1（TNFR 1）结合蛋白，在物理和功能上将TNFR 1与NADPH氧化酶偶联。在小鼠和人类细胞中，RFK结合TNFR 1-死亡结构域和p22（phox），NADPH氧化酶同种型的共同亚基。RFK介导的TNFR 1和p22（phox）的桥接是TNF诱导的ROS产生的先决条件，但不是Toll样受体诱导的ROS产生的先决条件。外源性黄素单肽或FAD能够完全替代TNF刺激RFK缺陷细胞中的NADPH氧化酶。RFK在NADPH氧化酶的必需辅基FAD的合成中是限速的。结果表明，TNF，通过激活RFK，增强NADPH氧化酶，组装和激活NADPH氧化酶的关键步骤中的FAD的掺入。
Reactive oxygen species (ROS) produced by NADPH oxidase function as defence and signalling molecules related to innate immunity and various cellular responses(1,2). The activation of NADPH oxidase in response to plasma membrane receptor activation depends on the phosphorylation of cytoplasmic oxidase subunits, their translocation to membranes and the assembly of all NADPH oxidase components(3). Tumour necrosis factor (TNF) is a prominent stimulus of ROS production, but the molecular mechanisms by which TNF activates NADPH oxidase are poorly understood. Here we identify riboflavin kinase (RFK, formerly known as flavokinase(4)) as a previously unrecognized TNF-receptor-1 (TNFR1)-binding protein that physically and functionally couples TNFR1 to NADPH oxidase. In mouse and human cells, RFK binds to both the TNFR1-death domain and to p22(phox), the common subunit of NADPH oxidase isoforms. RFK-mediated bridging of TNFR1 and p22(phox) is a pre-requisite for TNF-induced but not for Toll-like-receptor-induced ROS production. Exogenous flavin mononucleotide or FAD was able to substitute fully for TNF stimulation of NADPH oxidase in RFK-deficient cells. RFK is rate-limiting in the synthesis of FAD, an essential prosthetic group of NADPH oxidase. The results suggest that TNF, through the activation of RFK, enhances the incorporation of FAD in NADPH oxidase enzymes, a critical step for the assembly and activation of NADPH oxidase.