Endocytic Trafficking in C. elegans and Mammals

线虫和哺乳动物的内吞贩运

• 批准号: 6744412
• 负责人: Barth Demian Grant
• 金额: $ 27.59万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-05 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6744412
• 关键词: Caenorhabditis elegans; chemical binding; endocytosis; gene mutation; immunoelectron microscopy; intracellular transport; membrane proteins; nucleotides; protein structure function; protein transport

DESCRIPTION (provided by applicant): Regulated membrane and protein transport is a central component of a multitude of biological processes and is critically important in human heath. For example, transport defects are implicated in hypercholesterolemia, Huntington's disease, and myeloid leukemia. Thus, elaborating molecular mechanisms of membrane trafficking are profoundly important to both basic and applied research. Our interests are in exploiting advantageous features of C. elegans and mammalian cells to investigate one of the least understood steps in endocytic traffic-the return of internalized molecules to the cell surface via recycling endosomes. Surprisingly little is known of the molecules that mediate and regulate this step of recycling. Initial studies indicate this process is highly conserved in metazoans, and may be distinct from related processes in microbes like yeast. Using a genetic approach in C. elegans, we have identified novel proteins that are critical for the recycling process in vivo. One of these, RME-1, is a peripheral membrane protein of the recycling endosome that regulates export from the recycling endosome in a process thought to utilize membrane tubules. RME-1 appears highly conserved between nematodes and mammals in both structure and basic function and is one of the first proteins clearly implicated in this specific recycling step. Mutations in a second protein, GUM-l, cause the same biological defects as mutations in RME-I. Furthermore, GUM-1 is required for the localization of RME-1 to endosomes. The molecular identity of the GUM-1 protein and the mechanism by which it regulates RME-1 localization are currently unknown. We plan to decipher the biology of endocytic recycling by conducting an in-depth multi-pronged analysis of RME-1 and GUM-1 and by applying novel approaches toward the identification of additional proteins that act with RME-1 and GUM-1 in the process of recycling. Our specific aims are: l) To test key working hypotheses that RME-1 is regulated by nucleotide binding and membrane association, and that RME-1 participates in membrane tubule formation. 2) To characterize GUM-l, a novel regulator of endocytic recycling in C. elegans and mammals. 3) To identify additional mediators and regulators of endocytic recycling in C. elegans. By combining the power of C. elegans genetics and mamalian cell biology this work will significantly advance our understanding of .the mechanisms determining a key metazoan membrane transport process.

描述（由申请人提供）：调节的膜和蛋白质运输是多种生物过程的核心组成部分，对人类健康至关重要。例如，运输缺陷与高胆固醇血症、亨廷顿病和骨髓性白血病有关。因此，阐明膜运输的分子机制对于基础研究和应用研究都非常重要。 我们的兴趣是利用秀丽隐杆线虫和哺乳动物细胞的有利特征来研究内吞运输中最不为人所知的步骤之一——通过循环内体将内化分子返回到细胞表面。令人惊讶的是，人们对介导和调节这一回收步骤的分子知之甚少。初步研究表明，这一过程在后生动物中高度保守，并且可能与酵母等微生物中的相关过程不同。利用秀丽隐杆线虫的遗传方法，我们发现了对体内回收过程至关重要的新型蛋白质。其中之一，RME-1，是再循环内体的外周膜蛋白，在被认为利用膜小管的过程中调节再循环内体的输出。 RME-1 在线虫和哺乳动物之间的结构和基本功能都高度保守，并且是第一个明确参与该特定回收步骤的蛋白质之一。第二种蛋白质GUM-1的突变引起与RME-1的突变相同的生物学缺陷。此外，GUM-1 是 RME-1 定位到核内体所必需的。 GUM-1 蛋白的分子特性及其调节 RME-1 定位的机制目前尚不清楚。 我们计划通过对 RME-1 和 GUM-1 进行深入的多管齐下分析，并应用新方法来鉴定在回收过程中与 RME-1 和 GUM-1 相互作用的其他蛋白质，从而破译内吞回收的生物学原理。我们的具体目标是： l) 测试 RME-1 受核苷酸结合和膜缔合调节以及 RME-1 参与膜小管形成的关键工作假设。 2) 表征GUM-1，一种新的线虫和哺乳动物内吞再循环调节剂。 3) 确定秀丽隐杆线虫内吞再循环的其他介质和调节因子。通过结合线虫遗传学和哺乳动物细胞生物学的力量，这项工作将显着增进我们对决定关键后生动物膜运输过程的机制的理解。