Both Max and TFE3 cooperate with Smad proteins to bind the plasminogen activator inhibitor-1 promoter, but they have opposite effects on transcriptional activity
Both Max and TFE3 cooperate with Smad proteins to bind the plasminogen activator inhibitor-1 promoter, but they have opposite effects on transcriptional activity
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DOI：
10.1074/jbc.m211734200
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发表时间：
2003-03-28
影响因子：
4.8
通讯作者：
Kerppola, T
中科院分区：
文献类型：
--
作者：
Grinberg, AV;Kerppola, T
转化生长因子（TGF）-β在很大程度上通过Smad家族成员与其他转录因子之间的组合相互作用来调节基因表达。碱性螺旋-环-螺旋亮氨酸拉链（bHLHZIP）蛋白TFE 3和Smad 3协同激活纤溶酶原激活物抑制剂-1（派-1）以及其它基因的转录。我们研究了不同的bHLHZIP和Smad家族蛋白之间的相互作用。在不存在DNA的情况下，TFE 3、TFEB和Max与Smad 3和Smad 4相关，位于派-1启动子的PE2.1元件处。这些相互作用是由相应蛋白质的亮氨酸拉链和MH 1区域介导的。未观察到与E47 bHLH家族蛋白的相互作用。嵌合蛋白，其中来自bHLHZIP或bZIP蛋白的亮氨酸拉链与异源bHLH结构域融合，在不存在DNA的情况下和在PE2.1元件处与Smad蛋白缔合。使用表面等离子体共振分析检查bHLHZIP和Smad蛋白在PE2.1元件处结合的动力学。TFE 3与Smad蛋白具有协同DNA结合作用，而E47与Smads之间没有观察到协同性。最大抑制Smad 3和TGF-β在派-1启动子的转录激活，而TFE 3和TFEB刺激转录激活。这些结果表明，Smad家族蛋白可以与几种bHLHZIP蛋白相互作用，导致不同的转录结果。
Transforming growth factor (TGF)-beta regulates gene expression in large part through combinatorial interactions between members of the Smad family and other transcription factors. The basic helix-loop-helix leucine zipper (bHLHZIP) protein TFE3 and Smad3 synergistically activate transcription of the plasminogen activator inhibitor-1 (PAI-1) as well as other genes. We investigated interactions among different bHLHZIP and Smad family proteins. TFE3, TFEB, and Max associated with Smad3 and Smad4 in the absence of DNA and at the PE2.1 element of the PAI-1 promoter. These interactions were mediated by the leucine zipper and MH1 regions of the respective proteins. No interactions were observed with the E47 bHLH family protein. Chimeric proteins, in which leucine zippers from bHLHZIP or bZIP proteins were fused to heterologous bHLH domains, associated with Smad proteins both in the absence of DNA and at the PE2.1 element. The kinetics of bHLHZIP and Smad protein binding at the PE2.1 element were examined using surface plasmon resonance analysis. TFE3 exhibited cooperative DNA binding with Smad proteins, whereas no cooperativity was observed between E47 and Smads. Max inhibited transcription activation by Smad3 and TGF-beta at the PAI-1 promoter, whereas TFE3 and TFEB stimulated transcription activation. These results suggest that Smad family proteins can interact with several bHLHZIP proteins, resulting in different transcriptional outcomes.