Inhibition of NF-κB by S-nitrosylation
Inhibition of NF-κB by S-nitrosylation
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DOI：
10.1021/bi002239y
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发表时间：
2001-02-13
期刊：
影响因子：
2.9
通讯作者：
Stamler, JS
中科院分区：
文献类型：
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作者：
Marshall, HE;Stamler, JS
目前尚不清楚转录的氧化还原调节是否是转录因子直接氧化还原相关修饰的结果，或者是否发生在其他一些氧化还原敏感步骤。一个障碍是无法在体内证明转录因子的氧化还原相关修饰。氧化还原敏感转录激活剂 NF-kappaB (p50-p65) 就是一个很好的例子。其体外活性可通过 DNA 相互作用 p50 亚基中关键硫醇的 S-亚硝基化来抑制，但一氧化氮合酶 (NOS) 对 NF-kappaB 活性的调节归因于其他机制。在此，我们表明细胞 NF-kappaB 活性实际上受 S-亚硝基化调节。我们观察到 S-亚硝基半胱氨酸和细胞因子激活的 NOS2 都会抑制人呼吸细胞或小鼠巨噬细胞中的 NF-κB。通过向细胞提取物中添加去亚硝基化剂二硫苏糖醇可逆转这种抑制作用，而 NO 生物活性并不影响 TNF α 诱导的 I kappaB α 降解或 p65 的核转位。体外重复这些条件会导致重组 p50 发生 S-亚硝基化，从而抑制其与 DNA 的结合，并且二硫苏糖醇可以逆转这种作用。此外，在细胞中检测到 S-亚硝基化 p50 增加，并且该水平受到 TNF α 的调节。综上所述，这些数据表明 p50 的 S-亚硝基化是 NF-kappaB 调节的生理机制。
It is not clear if redox regulation of transcription is the consequence of direct redox-related modifications of transcription factors, or if it occurs at some other redox-sensitive step. One obstacle has been the inability to demonstrate redox-related modifications of transcription factors in vivo. The redox-sensitive transcriptional activator NF-kappaB (p50-p65) is a case in point. Its activity in vitro can be inhibited by S-nitrosylation of a critical thiol in the DNA-interacting p50 subunit, but modulation of NF-kappaB activity by nitric oxide synthase (NOS) has been attributed to other mechanisms. Herein we show that cellular NF-kappaB activity is in fact regulated by S-nitrosylation. We observed that both S-nitrosocysteine and cytokine-activated NOS2 inhibited NF-kappaB in human respiratory cells or murine macrophages. This inhibition was reversed by addition of the denitrosylating agent dithiothreitol to cellular extracts, whereas NO bioactivity did not affect the TNF alpha -induced degradation of I kappaB alpha or the nuclear translocation of p65. Recapitulation of these conditions in vitro resulted in S-nitrosylation of recombinant p50, thereby inhibiting its binding to DNA, and this effect was reversed by dithiothreitol. Further, an increase in S-nitrosylated p50 was detected in cells, and the level was modulated by TNF alpha. Taken together, these data suggest that S-nitrosylation of p50 is a physiological mechanism of NF-kappaB regulation.