Studies of the effects of phosphorylation and protein interactions on ATP-binding casette transporter activity

蛋白质Ycf1p是在所有生物体中发现的膜蛋白的大超家族的成员。通过利用ATP的能量，被称为细胞的能量货币，这些蛋白质积极地将溶质运输进出细胞，调节其他蛋白质的功能，或打开孔或通道以允许带电物质通过。这些使用ATP的膜蛋白具有保守的分子结构，其包含嵌入细胞包膜中的两个区域（称为膜）和位于细胞内的两个区域（称为细胞质）。对这一过程的适当调节是必不可少的，因为许多遗传疾病，包括囊性纤维化和肾上腺脑白质营养不良，都是由这个无处不在的超家族中不同蛋白质的功能障碍引起的。Ycf1p将毒素从细胞的一部分（细胞质）转运到细胞内的膜结合区室。这样，Ycf1p通过隔离有毒分子来解毒细胞。Ycf1p是ATP使用蛋白超家族的一个特定亚类的原型，与导致肿瘤对化疗药物产生耐药性的多药耐药蛋白相似。Ycf1p和Ycf1p样蛋白除了整个超家族共有的最小结构外，还具有独特的结构区域。Ycf1p的作用是以复杂的方式调节的。细胞中Ycf1p的生物化学修饰导致在特定位点添加带电基团，可以根据修饰的位点激活或灭活蛋白质。Ycf1p还结合许多其他蛋白质，这些蛋白质调节Ycf1p的转运功能或赋予Ycf1p其他功能。该提案描述了基于生物化学，生物物理学和细胞生物学的实验，旨在深入了解Ycf1p活性如何控制，这将适用于超家族的其他成员。到目前为止，很少有研究已经完成，以解决了解在这类重要的蛋白质的调控机制。我们将调查参与中继信息从ATP的利用到毒素的运输，并结合辅助蛋白的个别Ycf1p蛋白片段的相互作用。我们将进一步讨论生化修饰如何改变Ycf1p的结构和相互作用。最后，我们将进行实验，以获得Ycf1p的3D图片，这将产生许多关于Ycf1p中独特区域的组织的信息，这些信息具有整个超家族共享的最小架构。拟议的研究将阐明一些控制Ycf1p活性的复杂机制。由于Ycf1p是一个庞大的蛋白质超家族的一部分，这些蛋白质具有共同的结构和机制特征，因此我们的Ycf1p研究将产生关于这类蛋白质的信息，这类蛋白质在整个生物学中是保守的。

The protein Ycf1p is a member of a large superfamily of membrane proteins found in all organisms. By utilizing the energy of ATP, known as the energy currency of the cell, these proteins actively transport solutes into and out of the cell, regulate the function of other proteins, or open pores or channels to allow charged species to pass through. These ATP-using membrane proteins have a conserved molecular architecture that contains two regions embedded in the cellular envelope (known as the membrane) and two regions located inside the cell (known as the cytoplasm). Proper regulation of this process is essential, as many genetic diseases, including cystic fibrosis and adrenoleukodystrophy, result from dysfunction of different proteins in this ubiquitous superfamily.******Ycf1p transports toxins from one part of the cell (cytoplasm) to a membrane-bound compartment that is also found inside the cell. In this way, Ycf1p detoxifies the cell by sequestering poisonous molecules. Ycf1p is a prototype of a specific subclass of the ATP-using protein superfamily and shares similarily with the multidrug-resistance proteins that cause tumors to be resistant to chemotherapy drugs. Ycf1p and Ycf1p-like proteins posses a unique structural region in addition to the minimum architecture shared by the entire superfamily. Ycf1p action is regulated in a complex fashion. Biochemical modification of Ycf1p in the cell, which results in the addition of a charged group to specific sites, can activate or deactivate protein depending on the site modified. Ycf1p also binds a number of other proteins, which regulate Ycf1p transport function or ascribe other functions to Ycf1p.******This proposal describes biochemical, biophysical, and cell biology-based experiments designed to gain insights into how Ycf1p activity is controlled, which will be applicable to other members of superfamily. To date, few studies have been done to address understand the mechanism of regulation in this important class of proteins. We will investigate interactions of individual Ycf1p protein segments that are involved in relaying information from the utilization of ATP to transport of toxins, and that bind accessory proteins. We will further address how biochemical modification changes the structure and interactions of Ycf1p. Finally, we will conduct experiments to obtain a 3D picture of Ycf1p, which will yield much sought-after information on the organization of the unique region in Ycf1p with the minimum architecture shared by the entire superfamily. The proposed research will elucidate some of the complex mechanisms by which Ycf1p activity is controlled. Because Ycf1p is part of a large superfamily of proteins that share common structural and mechanistic features, our Ycf1p studies will yield information about this class of proteins, which are conserved throughout biology.**