Dopamine Transporter--structure/function Studies Of Tran

多巴胺转运体（DAT）是一个主要的脑受体部位，与可卡因的奖赏和欣快特性相关。MNB科学家发现，删除DAT和SERT是消除小鼠可卡因条件性位置偏好所必需的。DAT是目前产生帕金森病最佳模型的每种多巴胺选择性毒素的作用所必需的。DAT结构-功能关系及其与SERT的关系的分析在今年继续进行，进一步表征了所选氨基酸侧链在转运蛋白功能中的作用。这些研究集中在单和多结构域的大鼠多巴胺转运蛋白的氨基酸变化的利益和表征的氨基酸变化所产生的人类等位基因变异体的DAT序列在今年的其他研究报告。在这一年中报道的研究记录了丝氨酸和苏氨酸取代对激活或抑制PKC、MAP、MEK激酶和IP 3激酶途径的药物的DAT活性作用的惊人的大的影响。在这一年完成的研究还确定了一个大的影响共表达的PKC依赖性PP 1抑制剂，KEPI（在本实验室确定为吗啡上调基因）的功能共表达DAT。研究报告在这一年也文件DAT点突变的选择性影响多巴胺从DAT表达细胞的流出。这些见解应继续有助于鉴定可能在体内具有可卡因拮抗剂活性的小分子化合物的结构-功能特征、与DAT调节相关的结构-功能关系以及DAT药理学中的人类个体差异。

The dopamine transporter (DAT) has been a principal brain receptor site that has been correlated with the rewarding and euphoric properties of cocaine. MNB scientists have found that deletion of DAT and SERT are required to eliminate cocaine conditioned place preferences in mice. DAT is required for the actions of each of the current dopamine-selective toxins that produce the best models of Parkinson's disease. Analyses of DAT structure- function relationships, and their relationships with SERT, continued during this year with further characterization of the roles of selected amino acid sidechains in transporter functions. These studies have focused on single- and multiple-domaine amino acid changes of interest in the rat dopamine transporter and on characterization of the amino acid changes produced by human allelic variants of the DAT sequence identified in other studies reported during this year. Studies reported during this year document surprisingly large effects of serine and threonine substitutions on the DAT activity effects of drugs that activate or inhibit PKC, MAP, MEK kinase, and IP3 kinase pathways. Studies completed during this year have also identified a large effect of coexpression of the PKC-dependent PP1 inhibitor, KEPI (identified in this laboratory as a morphine-upregulated gene)on the function of coexpressed DAT. Studies reported during this year also document surprisingly-selective effects of DAT point mutations on efflux of dopamine from DAT-expreessing cells. These insights should continue to help in identification of structure- function features of small molecule compounds possibly active in vivo as cocaine antagonists, structure-function relationships relevant to DAT regulation, and human individual differences in DAT pharmacology.