Time-dependent activation of Phox2a by the cyclic AMP pathway modulates onset and duration of p27Kip1 transcription.
Time-dependent activation of Phox2a by the cyclic AMP pathway modulates onset and duration of p27Kip1 transcription.
复制标题
环 AMP 通路对 Phox2a 的时间依赖性激活可调节 p27Kip1 转录的起始时间和持续时间。
DOI：
10.1128/mcb.01928-08
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发表时间：
2009
影响因子：
5.3
通讯作者：
Andrisani,OuraniaM
中科院分区：
文献类型：
--
作者：
Shin,MinHwa;Mavila,Nirmala;Wang,Wen-Horng;VegaAlvarez,Sasha;Hall,MarkC;Andrisani,OuraniaM
在去甲肾上腺素能祖细胞中，Phox2a通过诱导p27Kip1转录来调节细胞周期退出和神经元分化，以响应环磷酸腺苷(CAMP)途径的激活。CAMP介导的Phox2a激活机制尚不清楚。我们通过质谱学鉴定了Phox2a中的一簇磷酸丝氨酸-脯氨酸位点。Ser206似乎是最显著的磷酸化位点。磷酸Ser206Phox2a抗体检测到Phox2a的去磷酸化依赖于cAMP通路的激活，cAMP通路发生在去甲肾上腺素能CAD细胞的神经元分化之前。利用在可诱导的CAD细胞系中表达的丝氨酸到丙氨酸和丝氨酸到天冬氨酸的替代突变体，我们证明了Phox2a的转录活性受两个连续的cAMP依赖事件的调节：第一，cAMP信号促进至少一个位点(Ser206)Phox2a的去磷酸化，从而允许Phox2a结合DNA并启动p27Kip1转录；第二，在磷酸丝氨酸簇(Ser202和Ser208)去磷酸化之后，Phox2a被Ser153上的蛋白激酶A(PKA)磷酸化，这阻止了Phox2a与DNA的结合并终止了p27Kip1的转录。这代表了一种新的机制，即同样的刺激，cAMP信号，首先通过Ser206的去磷酸化激活Phox2a，然后，在固有的延迟之后，通过依赖于PKA的Ser153的磷酸化来失活Phox2a，从而调节p27Kip1转录的开始和持续时间。
In noradrenergic progenitors, Phox2a mediates cell cycle exit and neuronal differentiation by inducing p27Kip1transcription in response to activation of the cyclic AMP (cAMP) pathway. The mechanism of cAMP-mediated activation of Phox2a is unknown. We identified a cluster of phosphoserine-proline sites in Phox2a by mass spectrometry. Ser206 appeared to be the most prominent phosphorylation site. A phospho-Ser206 Phox2a antibody detected dephosphorylation of Phox2a that was dependent on activation of the cAMP pathway, which occurred prior to neuronal differentiation of noradrenergic CAD cells. Employing serine-to-alanine and serine-to-aspartic acid Phox2a substitution mutants expressed in inducible CAD cell lines, we demonstrated that the transcriptional activity of Phox2a is regulated by two sequential cAMP-dependent events: first, cAMP signaling promotes dephosphorylation of Phox2a in at least one site, Ser206, thereby allowing Phox2a to bind DNA and initiate p27Kip1transcription; second, following dephosphorylation of the phosphoserine cluster (Ser202 and Ser208), Phox2a becomes phosphorylated by protein kinase A (PKA) on Ser153, which prevents association of Phox2a with DNA and terminates p27Kip1transcription. This represents a novel mechanism by which the same stimulus, cAMP signaling, first activates Phox2a by dephosphorylation of Ser206 and then, after a built-in delay, inactivates Phox2a via PKA-dependent phosphorylation of Ser153, thereby modulating onset and duration of p27Kip1transcription.