Phosphorylation of serine 276 is essential for p65 NF-κB subunit-dependent cellular responses
Phosphorylation of serine 276 is essential for p65 NF-κB subunit-dependent cellular responses
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DOI：
10.1016/s0006-291x(02)02932-7
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发表时间：
2003-01-24
影响因子：
3.1
通讯作者：
Nakano, H
中科院分区：
文献类型：
--
作者：
Okazaki, T;Sakon, S;Nakano, H
研究表明，几个血清残基的磷酸化，尤其是p65 NF-kappaB亚基反式激活（TA）结构域中的磷酸化对其转录活性很重要。然而，p65的磷酸化位点仍然存在争议。为了研究磷酸化的生物学意义并确定p65的关键磷酸化位点，我们用p65的各种丝氨酸-丙氨酸（SA）取代突变体重建了来自p65（-/-）小鼠的鼠胚胎成纤维细胞（MEFs）。出乎意料的是，TA结构域中的突变体，包括S529 A、S536 A和S529 A/S536 A，完全挽救了p65（-/-）MEFs的缺陷，如通过肿瘤坏死因子（TNF）或白细胞介素-1（IL-1）诱导的IL-6产生和对TNF诱导的细胞死亡的保护所评估的。另一方面，S276 A突变体具有受损的拯救这些反应的能力。此外，TNF诱导的p65磷酸化在S276 A突变体中严重受损，表明S276是p65的主要磷酸化位点，其磷酸化对于p65依赖性细胞反应是必需的。(C)2002 Elsevier Science（美国）。All rights reserved.
Phosphorylation of several scrine residues especially in the transactivation (TA) domain of p65 NF-kappaB subunit has been suggested to be important for its transcriptional activity. However, the responsible phosphorylation site of p65 remains controversial. To investigate the biological significance of phosphorylation and to determine the critical phosphorylation sites of p65, we reconstituted murine embryonic fibroblasts (MEFs) from p65(-/-) mice with various serine to alanine (SA)-substituted mutants of p65. Unexpectedly, mutants in the TA domain, including S529A, S536A, and S529A/S536A, completely rescued the defect of p65(-/-) MEFs as assessed by tumor necrosis factor (TNF)- or interleukin-1 (IL-1)-induced IL-6 production and protection from TNF-induced cell death. On the other hand, S276A mutant had an impaired ability to rescue these responses. Moreover, TNF-induced phosphorylation of p65 was severely impaired in S276A mutant, indicating that S276 is the major phosphorylation site of p65 and its phosphorylation is essential for p65-dependent cellular responses. (C) 2002 Elsevier Science (USA). All rights reserved.