Enhancement of nuclear factor-κB acetylation by coactivator p300 and HIV-1 Tat proteins
Enhancement of nuclear factor-κB acetylation by coactivator p300 and HIV-1 Tat proteins
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DOI：
10.1074/jbc.m107848200
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发表时间：
2002-02-15
影响因子：
4.8
通讯作者：
Kashanchi, F
中科院分区：
文献类型：
--
作者：
Furia, B;Deng, L;Kashanchi, F
核因子 (NF)-kappaB 转录因子参与大量正常细胞和有机体过程的控制，例如免疫和炎症反应、发育过程、细胞生长和细胞凋亡。人类免疫缺陷病毒 1 型 (HIV-1) 基因组的转录取决于细胞内环境，在细胞内环境中，整合的病毒 DNA 受到病毒调节蛋白（如 Tat）和宿主细胞转录因子（如 NF-κB）之间复杂的相互作用的调节，与病毒长末端重复区域相互作用。 CBP（CREB 结合蛋白）和 p300 含有内在的组蛋白乙酰转移酶 (HAT) 活性，已成为各种 DNA 结合转录因子的共激活剂。在这里，我们表明，p50 亚基以及 NF-kappaB 的 p50/p65，而不是其他因子，如 SP1、TFIB、聚合酶 II、TFIIA 或 p65，可以被 CBP/p300 HAT 结构域乙酰化。 p50 的乙酰化完全依赖于 HAT 结构域和 Tat 蛋白的存在，这意味着 Tat 通过帮助 CBP/p300 获得新伙伴并增加其功能库来影响转录机制。 p50 中的三个赖氨酸（Lys-431、Lys-440 和 Lys-441）均在体外乙酰化，并且观察到 p50、p53、Tat 和 I 型激活素受体在这些特定赖氨酸上的序列相似性。所有蛋白质均已被证明被 CBP/p300 HAT 结构域乙酰化。使用标记的 NF-kappaB 寡核苷酸时，通过链霉亲和素/生物素下拉测定可以明显看出，乙酰化 p50 增加了其 DNA 结合特性。 HIV-1 长末端重复序列上 DNA 结合的增加与转录速率的增加同时发生。因此，我们提出 NF-kappaB DNA 结合域的乙酰化有助于核易位和增强转录，并且还表明 CBP/p300 的底物特异性可以通过小肽分子（例如 HIV 编码的 Tat）来改变。
Nuclear factor (NF)-kappaB transcription factors are involved in the control of a large number of normal cellular and organismal processes, such as immune and inflammatory responses, developmental processes, cellular growth, and apoptosis. Transcription of the human immunodeficiency virus type 1 (HIV-1) genome depends on the intracellular environment where the integrate viral DNA is regulated by a complex interplay among viral regulatory proteins, such as Tat, and host cellular transcription factors, such as NF-kappaB, interacting with the viral long terminal repeat region. CBP (CREB-binding protein) and p300, containing an intrinsic histone acetyltransferase (HAT) activity, have emerged as coactivators for various DNA-binding transcription factors. Here, we show that the p50 subunit as well as the p50/p65 of NF-kappaB, and not other factors such as SP1, TFIIB, polymerase II, TFIIA, or p65, can be acetylated by CBP/p300 HAT domain. Acetylation of p50 was completely dependent on the presence of both HAT domain and Tat proteins, implying that Tat influences the transcription machinery by aiding CBP/p300 to acquire new partners and increase its functional repertoire. Three lysines, Lys-431, Lys-440, and Lys-441 in p50 were all acetylated an vitro, and a sequence similarity among p50, p53, Tat, and activin receptor type I on these particular lysines was observed. All proteins have been shown to be acetylated by the CBP/p300 HAT domain. Acetylated p50 increases its DNA binding properties, as evident by streptavidin/biotin pull-down assays when using labeled NF-kappaB oligonucleotides. Increased DNA binding on HIV-1 long terminal repeat coincided with increases in the rate of transcription. Therefore, we propose that acetylation of the DNA binding domain of NF-kappaB aids in nuclear translocation and enhanced transcription and also suggest that the substrate specificity of CBP/p300 can be altered by small peptide molecules, such as HIV-encoded Tat.