A TAT-DEF-Elk-1 peptide regulates the cytonuclear trafficking of Elk-1 and controls cytoskeleton dynamics
A TAT-DEF-Elk-1 peptide regulates the cytonuclear trafficking of Elk-1 and controls cytoskeleton dynamics
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DOI：
10.1523/jneurosci.2279-07.2007
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发表时间：
2007-12-26
影响因子：
5.3
通讯作者：
Caboche, Jocelyne
中科院分区：
文献类型：
--
作者：
Lavaur, Jeremie;Bernard, Frederic;Caboche, Jocelyne
转录因子Elk-1在细胞分化、增殖和凋亡中起关键作用。这种作用被认为是由其磷酸化激活的细胞外信号调节激酶（ERK），一个关键的翻译后事件的转录活性的三元复合物组成的Elk-1和血清反应因子（SRF）的二聚体在血清反应元件（SRE）的转录调控位点。除了其核定位，Elk-1被发现在神经元细胞的树突和索马中，并且最近的证据暗示了Elk-1的细胞质促凋亡功能，通过其与线粒体渗透性转换孔复合物的关联。因此，Elk-1的细胞核与细胞质定位似乎对其生物学功能至关重要。在这项研究中，我们表明，兴奋性神经递质，谷氨酸，诱导ERK依赖的Elk-1激活和核重新定位。我们证明了Elk-1在Ser 383/389上的磷酸化具有双重功能，并触发Elk-1核转位和SRE依赖的基因表达。将这些位点突变为无活性残基或使用特异性干扰Elk-1的DEF对接结构域的合成穿透肽（TAT-DEF-Elk-1），防止Elk-1核转位，而不干扰ERK或MSK 1（促分裂原和应激活化蛋白激酶1），ERK活化下游的CREB激酶。这导致与经典的ERK通路抑制剂相比，谷氨酸诱导的IEG调节的差异调节。使用TAT-DEF-Elk-1肽或Elk-1的显性负性版本，我们表明Elk-1磷酸化控制树突延伸、SRF和肌动蛋白表达水平以及细胞骨架动力学。
The transcription factor Elk-1 plays a key role in cell differentiation, proliferation and apoptosis. This role is thought to arise from its phosphorylation by activated extracellular signal-regulated kinases (ERKs), a critical posttranslational event for the transcriptional activity of the ternary complex composed of Elk-1 and a dimer of serum response factor (SRF) at the serum response element (SRE) regulatory site of transcription. In addition to its nuclear localization, Elk-1 is found in the dendrites and soma of neuronal cells and recent evidence implicate a cytoplasmic proapoptotic function of Elk-1, via its association with the mitochondrial permeability transition pore complex. Thus, the nuclear versus cytoplasmic localization of Elk-1 seems to be crucial for its biological function. In this study we show that the excitatory neurotransmitter, glutamate, induces an ERK-dependent Elk-1 activation and nuclear relocalization. We demonstrate that Elk-1 phosphorylation on Ser383/389 has a dual function and triggers both Elk-1 nuclear translocation and SRE-dependent gene expression. Mutating these sites into inactive residues or using a synthetic penetrating peptide (TAT-DEF-Elk-1), which specifically interferes with the DEF docking domain of Elk-1, prevents Elk-1 nuclear translocation without interfering with ERK nor MSK1 (mitogen-and stress-activated protein kinase 1), a CREB kinase downstream from ERK-activation. This results in a differential regulation of glutamate-induced IEG regulation when compared with classical inhibitors of the ERK pathway. Using the TAT-DEF-Elk-1 peptide or the dominant-negative version of Elk-1, we show that Elk-1 phosphorylation controls dendritic elongation, SRF and Actin expression levels as well as cytoskeleton dynamics.