p140/c-Abl that binds DNA is preferentially phosphorylated at tyrosine residues.
p140/c-Abl that binds DNA is preferentially phosphorylated at tyrosine residues.
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DOI：
10.1073/pnas.93.6.2387
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发表时间：
1996-03
影响因子：
11.1
通讯作者：
R. Dikstein;R. Agami;D. Heffetz;Y. Shaul
中科院分区：
文献类型：
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作者：
R. Dikstein;R. Agami;D. Heffetz;Y. Shaul
EP是在一些细胞和病毒基因的增强子和启动子区域发现的一种DNA元件。在此之前，我们已经鉴定出结合p140/c-Abl蛋白的DNA特异性识别该元件。在这里，我们发现磷酸化对于p140/c-Abl DNA结合活性和DNA-蛋白质复合物的形成是必不可少的。此外，通过细胞32P标记和蛋白质纯化，我们证明了体内ep - dna相关的p140/c-Abl是酪氨酸磷酸化蛋白。通过使用两种不同的c-Abl抗体，我们证明了在细胞提取物中存在两种不同的c-Abl群体。p140/c-Abl在数量上是次要群体，在丝氨酸和酪氨酸残基上都被大量磷酸化，并且在自磷酸化反应中很活跃。
EP is a DNA element found in the enhancer and promoter regions of several cellular and viral genes. Previously, we have identified the DNA binding p140/c-Abl protein that specifically recognizes this element. Here we show that phosphorylation is essential for the p140/c-Abl DNA binding activity and for the formation of DNA-protein complexes. Furthermore, by 32P labeling of cells and protein purification, we demonstrate that in vivo the EP-DNA-associated p140/c-Abl is a tyrosine phosphoprotein. By employing two different c-Abl antibodies, we demonstrate the existence of two distinct c-Abl populations in cellular extracts. p140/c-Abl is quantitatively the minor population, is heavily phosphorylated at both serine and tyrosine residues, and is active in autophosphorylation reactions.