Identification of p300-targeted acetylated residues in GATA4 during hypertrophic responses in cardiac myocytes
Identification of p300-targeted acetylated residues in GATA4 during hypertrophic responses in cardiac myocytes
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DOI：
10.1074/jbc.m707391200
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发表时间：
2008-04-11
影响因子：
4.8
通讯作者：
Hasegawa, Koji
中科院分区：
文献类型：
--
作者：
Takaya, Tomohide;Kawamura, Teruhisa;Hasegawa, Koji
锌指蛋白GATA4是心肌肥大反应性转录因子之一，在心肌细胞肥大刺激时增加其DNA结合和转录活性。在此过程中，GATA 4的活化部分通过内源性组蛋白乙酰转移酶（如转录辅激活因子p300）的乙酰化介导。然而，心肌细胞肥大过程中GATA4的p300靶向乙酰化位点尚未确定。通过突变分析，我们表明位于氨基酸311和322之间的4个赖氨酸残基是GATA 4和p300协同激活心钠素和内皮素-1启动子所需的。四突变体GATA 4，其中这4个赖氨酸残基同时突变，保留了定位在细胞核中的能力，并与辅因子，包括FOG-2，GATA 6，和p300相互作用，但缺乏p300诱导的乙酰化，DNA结合，和转录活性。此外，与野生型GATA4的四突变体GATA4的共表达损害了p300诱导的乙酰化，DNA结合，和野生型的转录活性。当我们使用慢病毒载体在新生大鼠心肌细胞中表达四突变体GATA4时，该突变体抑制苯肾上腺素诱导的细胞大小，蛋白质合成和肥大反应基因表达的增加。然而，它的表达并不影响基础状态。因此，我们已经确定了最关键的赖氨酸残基作为p300介导的乙酰化目标GATA 4在心肌细胞肥大反应。结果还表明，这些位点的同时突变的GATA 4特异性地抑制肥大反应作为显性负性形式，提供了进一步的证据，乙酰化的GATA 4作为心肌细胞肥大的关键核事件之一。
A zinc finger protein, GATA4, is one of the hypertrophy-responsive transcription factors and increases its DNA binding and transcriptional activities in response to hypertrophic stimuli in cardiac myocytes. Activation of GATA4 during this process is mediated, in part, through acetylation by intrinsic histone acetyltransferases such as a transcriptional coactivator p300. However, p300-targeted acetylated sites of GATA4 during myocardial cell hypertrophy have not been identified. By mutational analysis, we showed that 4 lysine residues located between amino acids 311 and 322 are required for synergistic activation of atrial natriuretic factor and endothelin-1 promoters by GATA4 and p300. A tetra-mutant GATA4, in which these 4 lysine residues were simultaneously mutated, retained the ability to localize in nuclei and to interact with cofactors including FOG-2, GATA6, and p300 but lacked p300-induced acetylation, DNA binding, and transcriptional activities. Furthermore, coexpression of the tetra-mutant GATA4 with wild-type GATA4 impaired the p300-induced acetylation, DNA binding, and transcriptional activities of the wild type. When we expressed the tetra-mutant GATA4 in neonatal rat cardiac myocytes using a lentivirus vector, this mutant suppressed phenylephrine-induced increases in cell size, protein synthesis, and expression of hypertrophy-responsive genes. However, its expression did not affect the basal state. Thus, we have identified the most critical lysine residues acting as p300-mediated acetylation targets in GATA4 during hypertrophic responses in cardiac myocytes. The results also demonstrate that GATA4 with simultaneous mutation of these sites specifically suppresses hypertrophic responses as a dominant-negative form, providing further evidence for the acetylation of GATA4 as one of critical nuclear events in myocardial cell hypertrophy.