Lung Kruppel-like factor contains an autoinhibitory domain that regulates its transcriptional activation by binding WWP1, an E3 ubiquitin ligase
Lung Kruppel-like factor contains an autoinhibitory domain that regulates its transcriptional activation by binding WWP1, an E3 ubiquitin ligase
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DOI：
10.1074/jbc.m103670200
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发表时间：
2001-08-03
影响因子：
4.8
通讯作者：
Lingrel, JB
中科院分区：
文献类型：
--
作者：
Conkright, MD;Wani, MA;Lingrel, JB
肺Kruppel样因子（LKLF/Kruppel样因子2）是Kruppel样转录因子家族的成员，主要在肺中表达，在其他器官如心脏、脾脏、骨骼肌和睾丸中表达水平较低。LKLF在肺发育和单阳性T细胞发育过程中是必不可少的，在小鼠胚胎发育过程中也是必不可少的。在这项研究中，我们进行了一系列的实验，以确定LKLF的激活结构域作为一种手段，以进一步推进理解的转录调控的分子机制，这种转录因子。使用缺失分析，它表明，LKLF包含一个转录激活结构域以及一个强大的自抑制子域。抑制性亚结构域能够独立地抑制其他强激活剂如病毒蛋白16、VP16的转录激活。当抑制结构域直接与VP 16融合时，或当抑制结构域通过不依赖于VP 16激活剂的GAL 4 DNA结合结构域独立地与DNA结合时，发生这种情况。LKLF自身抑制结构域单独过表达增强野生型LKLF的反式激活，表明抑制结构域结合了阻止LKLF反式激活的辅因子。酵母双杂交筛选鉴定了WWP1，一种特异性结合LKLF抑制结构域但不结合其他转录因子的E3泛素连接酶。在哺乳动物细胞中，WWP1通过结合LKLF和抑制反式激活作为辅因子发挥作用。这些数据表明，LKLF包含多个结构域，增强或抑制该因子作为转录激活因子发挥作用的能力;此外，E3泛素连接酶WWP1减弱了LKLF反式激活的调节。
Lung Kruppel-like factor (LKLF/Kruppel-like factor 2), a member of the Kruppel-like factor family of transcription factors, is expressed predominately in the lungs, with low levels of expression in other organs such as heart, spleen, skeletal muscle, and testis. LKLF is essential during pulmonary development and single-positive T-cell development and is indispensable during mouse embryogenesis. In this study, we performed a series of experiments to define the activation domain of LKLF as a means to further advance the understanding of the molecular mechanisms underlying transcriptional regulation by this transcription factor. Using deletion analysis, it is shown that LKLF contains a transcriptional activation domain as well as a strong autoinhibitory subdomain. The inhibitory subdomain is able to independently suppress transcriptional activation of other strong activators such as viral protein 16, VP16. This occurs either when the inhibitory domain is fused directly to VP16 or when the inhibitory domain is independently bound to DNA by GAL4 DNA-binding domain independent of the VP16 activator. Overexpression of the LKLF autoinhibitory domain alone potentiates transactivation by wild type LKLF, suggesting that the inhibitory domain binds a cofactor that prevents LKLF from transactivating. A yeast-two hybrid screen identified WWP1, an E3 ubiquitin ligase that binds specifically to the LKLF inhibitory domain but not to other transcription factors. In mammalian cells, WWP1 functions as a cofactor by binding LKLF and suppressing transactivation. These data demonstrate that LKLF contains multiple domains that either potentiate or inhibit the ability of this factor to function as an activator of transcription; moreover, regulation of LKLF transactivation is attenuated by an E3 ubiquitin ligase, WWP1.