ANALYSIS OF A NOVEL COCAINE INDUCED IMMEDIATE EARLY GENE

一种新型可卡因诱导的即早基因的分析

• 批准号: 6634225
• 负责人: PAUL F WORLEY
• 金额: $ 31.61万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-20 至 2004-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6634225
• 关键词: NMDA receptors; binding proteins; biological signal transduction; calcium channel; calcium flux; carbohydrate receptor; cocaine; drug addiction; gene induction /repression; genetically modified animals; glutamate receptor; inositol phosphates; intracellular transport; laboratory mouse; learning; memory; neural plasticity; neuropharmacology; point mutation; protein structure function; receptor coupling; regulatory gene; site directed mutagenesis; synapses; yeast two hybrid system

Recent advances in our understanding of cocaine addiction indicate that addiction involves mechanisms of neural plasticity. Immediate early genes (IEGs) are believed to play a role in mediating stimulus-induced neural plasticity and several laboratories have examined changes in gene expression that underlie the long-term neurochemical and behavioral laboratories have examined changes in gene expression that underlie the long-term neurochemical and behavioral effects of cocaine. Our laboratory has focused on the IEG termed Homer, which is rapidly induced by cocaine and appears to function at excitatory synapses to regulate the signaling coupling of metabotropic glutamate receptors (mGluR) and possibly NMDA receptors, to intracellular calcium stores. These glutamate receptors are enriched in neurons of the striatum and are known to be important in long-term neuronal plasticity, and in reward behaviors. Studies conducted during the prior funding period of this award have focused on the molecular and cellular functions of Homer. Homer possesses a N-terminal EVH1 domain that is essential for its interaction with mGluRs and other proteins. In Aim 1, we will determine the crystal structure of Homer EVH1 domain. We will also use yeast genetic approaches to provide detailed structure-function information regarding the specificity and regulation of Homer interactions. Aim 2 will examine the contribution of Homer to the function of metabotropic receptors in brain. A knock-in mouse will be generated that expresses a point mutant form of mGlur5 that does not interact with Homer. This genetic model will test the hypotheses that Homer is essential for normal mGluR signaling, for mGluR organization at the synapse, and for systems level plasticity that requires mGluRs; including cocaine sensitization. Aim 3 will continue our analysis of Homer-interacting proteins. The central hypothesis that is emerging from this work is that Homer functions to regulate the coupling of a specific set of membrane receptors to intracellular pools of releasable calcium. The contribution of Homer proteins to functional properties of ryanodine and inositol triphosphate receptors will also be examined. We will also characterize three novel proteins that have been identified to bind Homer. Preliminary studies indicate that these proteins may be important in coupling NMDA receptors to intracellular calcium pools, and in receptor trafficking. These studies promise to define important new mechanisms that contribute to the synaptic plasticity of cocaine addiction.

我们对可卡因成瘾的最新进展表明，成瘾涉及神经可塑性的机制。据信，立即的早期基因（IEG）在介导刺激引起的神经可塑性中起作用，几个实验室已经检查了基因表达的变化，这些变化是长期神经化学和行为实验室的基础，研究了基因表达的变化，这些变化是长期神经化学和行为影响ococaine的长期神经化学和行为影响的基础。我们的实验室专注于称为荷马的IEG，该IEG由可卡因迅速诱导，并且似乎在兴奋性突触下起作用，以调节代谢型谷氨酸受体（MGLUR）的信号传导偶联（MGLUR）和可能的NMDA受体，并可能是细胞内钙储备。这些谷氨酸受体富含纹状体的神经元，并在长期神经元可塑性和奖励行为中很重要。在此奖项的先前资助期间进行的研究集中在荷马的分子和细胞功能上。荷马拥有N末端EVH1结构域，这对于其与MGLURS和其他蛋白质的相互作用至关重要。在AIM 1中，我们将确定荷马EVH1域的晶体结构。我们还将使用酵母遗传方法来提供有关荷马相互作用的特异性和调节的详细结构功能信息。 AIM 2将研究荷马对大脑中代谢型受体功能的作用的贡献。将生成一种表达不与荷马相互作用的点突变体形式的敲入小鼠。该遗传模型将检验荷马对于正常的mglur信号，突触中的mglur组织以及需要mglurs的系统级可塑性至关重要的假设。包括可卡因敏化。 AIM 3将继续我们对本垒打蛋白的分析。 这项工作中出现的中心假设是，荷马功能是调节一组特定的膜受体与可释放钙的细胞内池的耦合。还将研究荷马蛋白对瑞氨烷和三磷酸肌醇的功能性能的贡献。我们还将表征三种已鉴定为结合荷马的新型蛋白质。初步研究表明，这些蛋白质可能在将NMDA受体与细胞内钙池以及受体运输中很重要。这些研究有望定义重要的新机制，从而有助于可卡因成瘾的突触可塑性。