THE ROLE OF DARPP-32, CK1, & CK2 IN MEDIATING THE MOLECULAR & BEHAVIORAL EFFECT

药物成瘾被认为是一种扰乱大脑自然奖励系统的疾病。已充分证实 滥用药物通过干扰多巴胺能神经传递发挥作用。它已被证明为 例如，多巴胺能系统在奖励相关行为中起着重要作用。的主要目标 这个项目是为了确定DARPP-32，一个关键的磷蛋白整合上游的机制， 多巴胺能信号并由酪蛋白激酶1（CK 1）和酪蛋白激酶2（CK 2）调节，介导这种作用 滥用药物和精神兴奋剂。使用磷酸特异性DARPP-32抗体和DARPP-32 磷酸化位点突变小鼠，我们已经证明DARPP-32磷酸化状态的变化， 以响应滥用药物的体内给药。我们已经确定了四种调节磷酸化 将DARPP-32转化为主要蛋白磷酸酶（PP-1）的有效抑制剂或转化为有效的 依赖于磷酸化位点组合的关键激酶（PKA）抑制剂。其中两个网站是 CK 1和CK 2的靶点。纹状体是多巴胺能功能的主要脑区，由以下组成： 两个重要的异质神经元细胞群。这两种神经元细胞群的重要性 上述观察结果是未知的。因此，我们将扩展我们以前的体内研究，包括 DARPP-32磷酸化的细胞类型特异性研究。此外，长期接触滥用药物， 已被证明可以诱导基因表达的变化，这些变化与可卡因的奖励作用有关。我们将 以细胞类型特异性的方式进行研究，以确定每种细胞类型对这些细胞的相对贡献。 方面的影响.目的研究急性和慢性给药的细胞类型特异性效应 药物滥用对DARPP-32磷酸化和mRNA翻译的影响。我们将进一步调查 CK 1和CK 2通过DARPP-32调节药物滥用效应的机制 转基因老鼠此外，我们将在搜索中表征新的CK 1和CK 2相互作用蛋白 来寻找假定的上游调节器。目的II和目的III将是CK 1和CK 2的作用的表征。 CK 2在药物滥用的作用。综合起来，这些研究将提供以下方面的详细信息： 以细胞类型特异性方式的DARPP-32磷酸化和DARPP-32介导的转录事件，和 还讨论了CK 1和CK 2在药物滥用行为中的重要性和调节。

Drug addiction is considered as a disease perturbing the brain's natural reward system. It is well established that drugs of abuse exert their effects by interfering with dopaminergic neurotransmission. It has been shown for example that the dopaminergic system plays an important role in reward-related behaviours. The major goal of this Project is to determine by which mechanisms DARPP-32, a crucial phosphoprotein integrating upstream dopaminergic signals and regulated by casein kinase 1 (CK1) and casein kinase 2 (CK2), mediates the effects of drugs of abuse and psychostimulants. Using phospho-specific DARPP-32 antibodies and DARPP-32 phospho-site mutant mice, we have demonstrated that changes in the phosphorylation state of DARPP-32 occur in response to the in vivo administration of drugs of abuse. We have identified four regulatory phosphorylation sites converting DARPP-32 either into a potent inhibitor of a major protein phosphatase (PP-1), or into a potent inhibitor of a crucial kinase (PKA) depending of the combination of sites phosphorylated. Two of these sites are targeted by CK1 and CK2. The striatum, the major brain region for the dopaminergic functions, is composed of two important heterogeneous neuronal cell populations. The importance of these two neuronal cell populations for the above mentioned observations is unknown. We will thus extend our previous in vivo studies to include cell-type specific studies of DARPP-32 phosphorylation. In addition, chronic exposure to drugs of abuse has been shown to induce changes in gene expression that are involved in the rewarding effects of cocaine. We will perform studies in a cell-type specific manner to determine the relative contribution of each cell-type to these effects. Aim I will be the characterization of cell-type specific effects of acute and chronic administration of drugs of abuse on DARPP-32 phosphorylation and on mRNA translation. We will further investigate the mechanism by which CK1 and CK2 modulate the effects of drugs of abuse through DARPP-32 using genetically modified mice. In addition we will characterize novel CK1 and CK2 interacting proteins in a search to find putative upstream regulators. Aim II and Aim III will be the characterization of the role of CK1 and CK2 in the actions of drugs of abuse. Taken together, these studies will provide detailed information on DARPP-32 phosphorylation and DARPP-32-mediated transcriptional events in a cell type specific manner, and also on the importance and the regulation of CK1 and CK2 in the actions of drugs of abuse.