AKT and CDK5/p35 mediate brain-derived neurotrophic factor induction of DARPP-32 in medium size spiny neurons in vitro
AKT and CDK5/p35 mediate brain-derived neurotrophic factor induction of DARPP-32 in medium size spiny neurons in vitro
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DOI：
10.1074/jbc.m606508200
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发表时间：
2007-03-09
影响因子：
4.8
通讯作者：
Ehrlich, Michelle E.
中科院分区：
文献类型：
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作者：
Bogush, Alexey;Pedrini, Steve;Ehrlich, Michelle E.
成熟的纹状体中型棘神经元表达多巴胺和环磷酸腺苷调节的磷酸蛋白32 kDa(DARPP-32)，但对其水平的调节机制或完全分化的神经元亚型的规范知之甚少。增加DARPP-32mRNA和/或蛋白水平的细胞外源分子包括脑源性神经营养因子(BDNF)、维甲酸和雌激素。BDNF在体外诱导DARPP-32需要磷脂酰肌醇3-激酶(PI3K)，但抑制蛋白激酶B/Akt的磷酸化并不能完全消除DARPP-32的表达。此外，对Akt的要求尚未确定。使用PI3K、Akt和细胞周期蛋白依赖性激酶5(CDK5)的药物抑制剂，以及结构性活性和显性阴性的PI3K、Akt、CDK5和p35病毒，我们检测了BDNF诱导的DARPP-32蛋白和/或mRNA的水平。我们证明了雷帕霉素的PI3K/Akt/哺乳动物靶点和CDK5/p35信号转导通路都有助于BDNF诱导DARPP-32蛋白水平，并且这种影响在转录和翻译水平上都有。PI3K似乎位于CDK5/p35的上游，它的激活可以导致p35蛋白水平的增加。这些数据支持在体外存在多种信号转导通路介导DARPP-32的表达，其中包括一条新的重要途径，PI3K通过该途径调节CDK5/p35的贡献。
Mature striatal medium size spiny neurons express the dopamine and cyclic AMP-regulated phosphoprotein, 32 kDa (DARPP-32), but little is known about the mechanisms regulating its levels or the specification of fully differentiated neuronal subtypes. Cell extrinsic molecules that increase DARPP-32 mRNA and/or protein levels include brain-derived neurotrophic factor (BDNF), retinoic acid, and estrogen. DARPP-32 induction by BDNF in vitro requires phosphatiaylinositide 3-kinase (PI3K), but inhibition of phosphorylation of protein kinase B/Akt does not entirely abolish expression of DARPP-32. Moreover, the requirement for Akt has not been established. Using pharmacologic inhibitors of PI3K, Akt, and cyclin-dependent kinase 5 (cdk5) and constitutively active and dominant negative PI3K, Akt, cdk5, and p35 viruses in cultured striatal neurons, we measured BDNF-induced levels of DARPP-32 protein and/or mRNA. We demonstrated that both the PI3K/Akt/mammalian target of rapamycin and the cdk5/p35 signal transduction pathways contribute to the induction of DARPP-32 protein levels by BDNF and that the effects are on both the transcriptional and translational levels. It also appears that PI3K is upstream of cdk5/p35, and its activation can lead to an increase in p35 protein levels. These data support the presence of multiple signal transduction pathways mediating expression of DARPP-32 in vitro, including a novel, important pathway via by which PI3K regulates the contribution of cdk5/p35.