Essential role of RelA Ser311 phosphorylation by ζPKC in NF-κB transcriptional activation
Essential role of RelA Ser311 phosphorylation by ζPKC in NF-κB transcriptional activation
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DOI：
10.1093/emboj/cdg370
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发表时间：
2003-08-01
期刊：
影响因子：
11.4
通讯作者：
Moscat, J
中科院分区：
文献类型：
--
作者：
Duran, A;Diaz-Meco, MT;Moscat, J
转录因子NF-kappaB的激活是控制许多刺激引发的细胞反应的核心。一旦从抑制性分子IkappaB中释放出来，NF-kappaB就会被转运到细胞核中，并且它必须被磷酸化才能激活转录。在zeta蛋白激酶C （PKC）缺陷的细胞中，NF-kappaB转录失活，RelA亚基对肿瘤坏死因子（tnf - α）的磷酸化反应严重受损。体外实验表明zetaPKC能直接磷酸化RelA。在这里，我们证明Ser311解释了RelA的zetaPKC磷酸化，并且该位点在体内响应tnf - α而磷酸化。此外，该残基的失活突变严重损害RelA的转录活性，阻断其抗凋亡功能，并消除RelA与共激活子CBP及其募集的相互作用，以及RNA聚合酶II （Pol II）与白细胞介素-6 （IL-6）启动子的相互作用。在zetaPKC-/-细胞中，内源性CBP与内源性RelA的相互作用以及Pol II与IL-6启动子的结合受到抑制。这些结果证明了zetaPKC在体内调节NF-kappaB活化的机制。
The activation of the transcription factor NF-kappaB is central to the control of the cellular response triggered by many stimuli. Once released from the inhibitory molecule IkappaB, NF-kappaB is translocated to the nucleus, and it has to be phosphorylated to activate transcription. In zeta protein kinase C (PKC)-deficient cells, NF-kappaB is transcriptionally inactive and the phosphorylation of the RelA subunit in response to tumor necrosis factor (TNF-alpha) is severely impaired. In vitro assays showed that zetaPKC directly phosphorylates RelA. Here we demonstrate that Ser311 accounts for zetaPKC phosphorylation of RelA and that this site is phosphorylated in vivo in response to TNF-alpha. Also, an inactivating mutation of that residue severely impairs RelA transcriptional activity, blocks its anti-apoptotic function and abrogates the interaction of RelA with the co-activator CBP as well as its recruitment, and that of RNA polymerase II (Pol II) with the interleukin-6 (IL-6) promoter. The interaction of endogenous CBP with endogenous RelA is inhibited in zetaPKC-/- cells, as well as the binding of Pol II to the IL-6 promoter. These results demonstrate the mechanism whereby zetaPKC regulates NF-kappaB activation in vivo.