The Regulation of Dopamine Neurotransmission by CDK5

描述(申请人提供)：多巴胺神经传递对许多生理功能很重要，其失调导致许多神经疾病。此前，我们发现神经元蛋白激酶CDK5通过将纹状体磷酸酶抑制剂DARPP-32转化为PKA抑制剂来调节多巴胺的疗效。利用药理学和转基因技术进一步研究了CDK5对多巴胺信号的调控，揭示了CDK5可能调控纹状体PKA活动的新机制。在这里，我们提供了CDK5通过PKA全酶RII2亚基的磷酸化来调节PKA的证据。此外，CDK5通过直接磷酸化磷酸二酯酶PDE4B或通过PKA和MAPK控制其调节细胞内cAMP水平。我们制作了条件性CDK5基因敲除模型，发现成年小鼠的CDK5基因敲除会导致多巴胺信号的严重变化。我们建议使用条件基因敲除方法进一步研究CDK5对纹状体神经元中PKA信号通路的依赖调节。我们建议描述在体外和完整的纹状体组织中，CDK5调节PKA的生化机制。这些研究将确定目标，并为开发神经和神经精神障碍的新治疗方法提出战略建议。公共卫生相关性：由多巴胺神经传递中断引起的神经精神障碍包括精神分裂症、注意力缺陷多动障碍和许多其他精神疾病。这项研究的目的是描述多巴胺神经传递的新机制，涉及神经元蛋白激酶CDK5，以便开发针对这些疾病的新的药物治疗方法。

DESCRIPTION (provided by applicant): Dopamine neurotransmission is important for many physiological functions and its dysregulation contributes to numerous neurological disorders. Previously, we showed that the neuronal protein kinase Cdk5 modulates dopamine efficacy by converting the striatal phosphatase inhibitor DARPP-32 into a PKA inhibitor. Further studies of the regulation of dopamine signaling by Cdk5 using pharmacology and transgenic technology have revealed novel mechanisms by which Cdk5 is likely to govern PKA activity in the striatum. Here we provide evidence that Cdk5 regulates PKA through phosphorylation of the PKA holoenzyme RII2 subunit. Furthermore, Cdk5 regulates intracellular cAMP levels through direct phosphorylation the phosphodiesterase PDE4B or controlling its regulation by PKA and MAPK. We made conditional Cdk5 knockout models and found that knockout in adult mice results in severe alterations in dopamine signaling. We propose to further study Cdk5- dependent regulation of PKA signaling pathways in striatal neurons using a conditional knockout approach. We propose to characterize the biochemical mechanisms by which Cdk5 regulates PKA both in vitro and in intact striatal tissue. These studies will identify targets and suggest strategies for the development of new treatments for neurological and neuropsychiatric disorders. PUBLIC HEALTH RELEVANCE: Neuropsychiatric disorders that are caused by disruptions in dopamine neurotransmission include schizophrenia, attention deficit hyperactivity disorder, and numerous other mental illnesses. The goal of this research is to delineate new mechanisms by which dopamine neurotransmission is regulated involving the neuronal protein kinase Cdk5 so that new pharmacotherapeutic treatments for these disorders can be developed.