Analysis of the Yeast MRP Subfamily of ABC Transporters

描述(由申请人提供)：多药耐药相关蛋白(MRP)亚家族的三磷酸腺苷结合盒(ABC)转运体在保护细胞免受药物和环境毒素如重金属(汞、砷、铅和镉)的影响方面发挥着关键作用。MRP(也称为ABCC)与其他ABC转运蛋白有两个显著的区别：1)它们含有一个额外的“N-末端延伸”，带有一个称为L0的保守区；2)它们以谷胱甘肽(GSH)结合物或复合体的形式运输底物。在这里，我们将使用在酿酒酵母中可用的强大的遗传、分子和细胞工具来解决MRP的几个关键问题。我们的具体目标是：1)确定MRP L0中的保守残基是否专用于GSH结合；2)评估最近为酵母MRP Ycflp发现的新的相互作用元件是否在MRP运输的一般机制中发挥不可或缺的作用；以及3)利用遗传和化学筛选，测试MRP的主要作用是处理潜在有害的“代谢碎屑”的可能性。总体而言，我们的分析可能会建议对基于MRP的疾病(例如DJS、PXE、囊性纤维化)进行更有效的治疗，和/或帮助减少环境毒素造成的损害。

DESCRIPTION (provided by applicant): The multidrug resistance-associated protein (MRP) subfamily of the ATP-binding cassette (ABC) transporters plays a key role in protecting cells from drugs and environmental toxins such as heavy metals (mercury, arsenic, lead, and cadmium). The MRPs (also called ABCCs) are distinguished from other ABC transporters by two striking hallmarks: 1) they contain an additional "N-terminal extension" with a conserved region called L0, and 2) they transport substrates in the form of glutathione (GSH)-conjugates or complexes. Here, we will use the powerful genetic, molecular, and cellular tools available in Saccharomyces cerevisiae to address several key issues of the MRPs. Our specific aims are to: 1) determine whether conserved residues within the L0 of MRPs are specific for GSH binding; 2) assess whether novel interactors, recently identified for the yeast MRP Ycflp, play an integral role in the general mechanism of MRP transport; and 3) test the possibility that a major role of the MRP's is to dispose of potentially harmful "metabolic detritus", using genetic and chemical screens. Overall, our analysis may suggest more effective therapies for MRP- based diseases (e.g. DJS, PXE, cystic fibrosis) and/or aid in reducing damage from environmental toxins.