MOLECULAR MECHANISMS OF DRUG/XENOBIOTIC ELIMINATION

描述（由申请人提供）：有机阴离子转运蛋白（OAT）家族介导多种环境毒素和临床重要药物（包括抗HIV治疗剂、抗肿瘤药物、抗生素、抗高血压药和抗炎药）的吸收、分布和排泄，因此对哺乳动物物种的生存至关重要。已鉴定出5种OAT（OAT 1、OAT 2、OAT 3、OAT 4和OAT 5），并在肾脏、肝脏、脑和胎盘中检测到其表达。这些器官中的OAT功能障碍显著导致肾、肝、神经和胎儿毒性和疾病。我们的长期目标是通过OAT途径确定药物/毒素处置的分子机制。在上一个赠款期间，取得了重大进展和生产力。我们已经绘制了OAT 1的膜拓扑结构。我们已经确定了对OAT功能至关重要的氨基酸残基。我们已经表明，OAT 1在肾LLC-PK 1细胞中形成同源寡聚体。上一个资助期的新发现导致在这一竞争性更新中建立了一个微调的研究计划和战略。我们建议测试的核心假设，即OAT的形式不仅同源，但也异源寡聚复合物在体内和运输活动的OAT赋予他们的寡聚状态。4个具体目标（SA）概述。在SA-1中，我们将确定OAT寡聚化的性质（同源与异源寡聚体）。在SA-2中，我们将评估OAT寡聚化在维持其功能方面的重要性。在SA-3中，我们将剖析OAT寡聚化的分子决定因素。在SA-4中，我们将比较OAT同源和异源寡聚体的药理学和调节特性。生物化学、分子生物学和生物物理学的综合方法将用于组织切片和培养细胞的拟议研究。从这些研究中获得的知识对于合理设计新药和抑制剂以最大限度地提高疗效和最小化毒性将是非常宝贵的，并将允许深入了解肾脏，肝脏，神经和胎儿毒性和疾病的分子，细胞和临床基础。

DESCRIPTION (provided by applicant): The organic anion transporter (OAT) family mediates the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs, including anti-HIV therapeutics, anti-tumor drugs, antibiotics, anti-hypertensives, and anti-inflammatories, and therefore is critical for the survival of mammalian species. 5 OATs have been identified (OAT1, OAT2, OAT3, OAT4, and OAT5) and their expression detected in kidney, liver, brain and placenta. OAT dysfunction in these organs significantly contributes to the renal, hepatic, neurological and fetal toxicity and disease. Our long-term goal is to define the molecular mechanisms underlying drug/toxin disposition through the OAT pathway. During the previous grant period, significant progress and productivity have been achieved. We have mapped the membrane topology of OAT 1. We have identified the amino acid residues critical for OAT function. We have showed that OAT1 form homo-oligomer in kidney LLC-PK1 cells. The new findings from the previous grant period led to the establishment of a fine-tuned research plan and strategy in this competing renewal. We propose to test the central hypothesis that OATs form not only homo- but also hetero-oligomeric complexes in vivo and that transport activities of OATs are conferred by their oligomerization states. 4 Specific Aims (SAs) are outlined. In SA-1, we will determine the nature of OAT oligomerization (homo-versus hetero-oligomers). In SA-2, we will assess the importance of OAT oligomerization in maintenance of its function. In SA-3, we will dissect the molecular determinants of OAT oligomerization. In SA-4, we will compare the pharmacological and regulatory properties of OAT homo-and hetero-oligomers. Combined approaches of biochemistry, molecular biology, and biophysics will be employed for the proposed studies in tissue slices, and cultured cells. The knowledge gained from these studies will be invaluable toward the rational design of novel drugs and inhibitors to maximize therapeutic efficacy and minimize toxicity, and will permit insight into the molecular, cellular, and clinical bases of renal, hepatic, neurological and fetal toxicity and disease.