Protein kinase A and C site-specific phosphorylations of LAP (NF-IL6) modulate its binding affinity to DNA recognition elements.
Protein kinase A and C site-specific phosphorylations of LAP (NF-IL6) modulate its binding affinity to DNA recognition elements.
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LAP (NF-IL6) 的蛋白激酶 A 和 C 位点特异性磷酸化调节其与 DNA 识别元件的结合亲和力。
DOI：
10.1172/jci117266
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Chojkier,M
中科院分区：
文献类型：
--
作者：
Trautwein,C;vanderGeer,P;Karin,M;Hunter,T;Chojkier,M
LAP （NF-IL6或C/EBP β）是一种肝脏转录激活蛋白，赋予肝脏特异性基因表达。由于LAP具有camp依赖性蛋白激酶a （PKA）的特征磷酸化受体序列，我们测试了PKA对LAP的体外磷酸化是否会调节其与特定DNA序列的相互作用。LAP的主要PKA磷酸化位点为Ser105，这是一个预测的PKA位点。正如预期的那样，这个PKA磷酸化位点在Ser105突变为Ala后消失。对LAP和LAP Asp105（模仿磷酸丝氨酸残基）的动力学研究表明，Ser105的磷酸化本身对DNA结合没有影响。通过对截断和突变的LAP肽的分析，PKA对其他位点的磷酸化，在Ser173和Ser223之间以及Ser240处，导致DNA结合抑制。纯化的蛋白激酶C在体外也能使LAP磷酸化，主要的磷酸化受体是LAP dna结合域内的Ser240。该残基的LAP磷酸化或引入Ser240到Asp突变导致其与DNA的结合明显减少。这些结果表明，LAP的位点特异性磷酸化可调节其靶基因的转激活。图片
LAP (NF-IL6 or C/EBP beta), is a liver transcriptional activator protein that confers liver-specific gene expression. Because LAP has a characteristic phosphoacceptor sequence for cAMP-dependent protein kinase A (PKA), we tested if in vitro phosphorylation of LAP by PKA modulates its interaction with specific DNA sequences. The major PKA phosphorylation site of LAP was identified as Ser105, which is a predicted PKA site. As expected, this PKA phosphorylation site disappears after mutation of Ser105 to Ala. Kinetic studies with LAP and LAP Asp105 (which mimics a phosphoserine residue) demonstrated that phosphorylation of Ser105 itself has no effect on DNA binding. Phosphorylation of other sites by PKA, identified in the region between Ser173 and Ser223 and at Ser240, by analysis of truncated and mutated LAP peptides, resulted in an inhibition of DNA binding. LAP was also phosphorylated by purified protein kinase C in vitro, and the major phosphoacceptor was shown to be Ser240 within the DNA-binding domain of LAP. Phosphorylation of LAP at this residue or introduction of a Ser240 to Asp mutation resulted in marked decrease in its binding to DNA. These results suggest that site-specific phosphorylations of LAP modulate transactivation of its target genes.Images
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影响因子：
56.9
作者：
M. Wegner;Z. Cao;M. Rosenfeld
通讯作者：
M. Wegner;Z. Cao;M. Rosenfeld
大鼠发育过程中肝脏特异性基因表达的转录和转录后控制模式的变化。
影响因子：
10.5
作者：
Panduro,A;Shalaby,F;Shafritz,DA
通讯作者：
Shafritz,DA
影响因子：
64.5
作者：
GONZALEZ, GA;MONTMINY, MR
通讯作者：
MONTMINY, MR
影响因子：
64.5
作者：
LICHTSTEINER, S;WUARIN, J;SCHIBLER, U
通讯作者：
SCHIBLER, U
影响因子：
10.5
作者：
METZ, R;ZIFF, E
通讯作者：
ZIFF, E