Analysis of the Yeast MRP Subfamily of ABC Transporters

描述（由申请人提供）：ATP结合盒（ABC）转运蛋白的多药耐药相关蛋白（MRP）亚家族在保护细胞免受药物和环境毒素（如重金属（汞、砷、铅和镉））影响方面发挥关键作用。MRP（也称为ABCC）与其他ABC转运蛋白的区别在于两个显著的标志：1）它们含有一个额外的“N-末端延伸”，具有一个称为LO的保守区域，以及2）它们以谷胱甘肽（GSH）-缀合物或复合物的形式转运底物。在这里，我们将使用强大的遗传，分子和酿酒酵母细胞的工具，以解决几个关键问题的MRP。我们的具体目标是：1）确定MRP的L0内的保守残基是否对GSH结合具有特异性; 2）评估最近鉴定的酵母MRP Ycflp的新相互作用物是否在MRP转运的一般机制中发挥不可或缺的作用;和3）使用遗传和化学筛选来测试MRP的主要作用是处理潜在有害的“代谢碎屑”的可能性。总的来说，我们的分析可能表明对基于MRP的疾病（例如DJS、PXE、囊性纤维化）更有效的疗法和/或有助于减少来自环境毒素的损伤。

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.