ERK2-mediated C-terminal serine phosphorylation of p300 is vital to the regulation of epidermal growth factor-induced keratin 16 gene expression
ERK2-mediated C-terminal serine phosphorylation of p300 is vital to the regulation of epidermal growth factor-induced keratin 16 gene expression
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DOI：
10.1074/jbc.m700264200
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发表时间：
2007-09-14
影响因子：
4.8
通讯作者：
Chang, Wen-Chang
中科院分区：
文献类型：
--
作者：
Chen, Yun-Ju;Wang, Ying-Nai;Chang, Wen-Chang
我们以前报道过表皮生长因子（EGF）通过激活细胞外信号调节激酶1和2（ERK 1/2）信号传导调节角蛋白16的基因表达，这反过来又增强了p300向角蛋白16启动子的募集。募集的p300在功能上与Sp1和c-Jun合作来调节角蛋白16的基因表达。本研究详细研究了p300引起的分子事件，从而EGF引起p300和Sp1之间的相互作用增强。EGF明显诱导p300磷酸化的时间和剂量依赖性，在体外和体内，通过激活ERK 2。首先在体外鉴定了六个潜在的ERK 2磷酸化位点，包括三个苏氨酸和三个丝氨酸残基，如通过序列分析所揭示的。这6个位点在体内的证实表明，这三个丝氨酸残基（Ser-2279，Ser-2315，和Ser-2366）的C端的p300是EGF的主要信号转导靶点。此外，p300的C-末端丝氨酸磷酸化刺激其组蛋白乙酰转移酶活性，并增强其与Sp1的相互作用。p300上的这些丝氨酸磷酸化位点控制p300向角蛋白16启动子的募集。当p300上的所有三个丝氨酸残基被丙氨酸取代时，EGF不再诱导角蛋白16的基因表达。综上所述，这些结果有力地表明，ERK 2介导的C-末端丝氨酸磷酸化的p300是一个关键的事件，在EGF诱导的角蛋白16的表达调控。这些结果也构成了第一个报告确定独特的p300磷酸化位点的ERK 2在体内诱导。
We previously reported that the epidermal growth factor (EGF) regulates the gene expression of keratin 16 by activating the extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling which in turn enhances the recruitment of p300 to the keratin 16 promoter. The recruited p300 functionally cooperates with Sp1 and c-Jun to regulate the gene expression of keratin 16. This study investigated in detail the molecular events incurred upon p300 whereby EGF caused an enhanced interaction between p300 and Sp1. EGF apparently induced time- and dose-dependent phosphorylation of p300, both in vitro and in vivo, through the activation of ERK2. The six potential ERK2 phosphorylation sites, including three threonine and three serine residues as revealed by sequential analysis, were first identified in vitro. Confirmation of these six sites in vivo indicated that these three serine residues (Ser-2279, Ser-2315, and Ser-2366) on the C terminus of p300 were the major signaling targets of EGF. Furthermore, the C-terminal serine phosphorylation of p300 stimulated its histone acetyltransferase activity and enhanced its interaction with Sp1. These serine phosphorylation sites on p300 controlled the p300 recruitment to the keratin 16 promoter. When all three serine residues on p300 were replaced by alanine, EGF could no longer induce the gene expression of keratin 16. Taken together, these results strongly suggested that the ERK2-mediated C-terminal serine phosphorylation of p300 was a key event in the regulation of EGF-induced keratin 16 expression. These results also constituted the first report identifying the unique p300 phosphorylation sites induced by ERK2 in vivo.