Mechanisms of membrane trafficking in endocytic and non-endocytic pathways

内吞和非内吞途径中的膜运输机制

• 批准号: 10330711
• 负责人: Steven H Caplan
• 金额: $ 54.61万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10330711
• 关键词: Actins; Address; Back; Binding Proteins; Biochemistry; Biogenesis; Biological; Biological Process; Cell Surface Receptors; Cell division; Cell membrane; Cellular biology; Centrosome; Cilia; Collaborations; Complex; Coupled; Cytoplasmic Tail; Cytoskeleton; Degradation Pathway; Destinations; Endosomes; Eukaryotic Cell; Event; Golgi Apparatus; Health; Homeostasis; Human; Knowledge; Laboratories; Lead; Link; Lysosomes; Mammalian Cell; Mediating; Membrane; Mission; Mitochondria; Molecular; Pathway interactions; Process; Proteins; Public Health; Recycling; Regulation; Research; Research Personnel; Retrieval; Signal Transduction; Sorting - Cell Movement; Tubular formation; United States National Institutes of Health; Vesicle; Whole Organism; Zebrafish; cilium biogenesis; genetic regulatory protein; improved; in vivo; late endosome; light microscopy; protein function; receptor; receptor internalization; receptor recycling; scaffold; sorting nexins; trafficking

PROJECT SUMMARY/ABSTRACT The internalization and recycling of receptors is a key biological process in all eukaryotic cells. The early/sorting endosome is the initial destination of receptors internalized from the plasma membrane (PM). This endosome serves as a major sorting station from which receptors are shunted to late endosomes and lysosomes for degradation, or are recycled back to the PM through a transitory network of vesicular and tubular recycling endosomes. Whereas a decade ago most researchers thought that active sorting directed proteins to the degradation pathways, targeting to the recycling pathway was thought to be largely a passive process that occurs by default. However, recent evidence supports active sorting to the recycling pathways by specific sorting nexin (SNX) and other proteins that bind to the cytoplasmic tails of receptors and specifically target them for recycling. Although recycling is an essential process for all mammalian cells, its complex regulation is poorly understood including the sorting of receptors on endosomal membranes, the budding and fission of vesicles and tubules from the endosome, and the transport of receptors back to the PM. As such, our knowledge of endosomal function lags substantially behind that of receptor internalization mechanisms. A key group of regulatory proteins that controls sorting and trafficking at the endosome is the retromer complex. Originally identified in the retrieval of biosynthetic cargo from endosomes to the Golgi complex, the retromer has recently been implicated in the regulation of a variety of key cellular pathways both within and beyond the scope of endocytic trafficking including endocytic recycling, mitochondrial homeostasis, the centrosome cycle and ciliogenesis. The retromer complex also interacts with other key endocytic regulatory proteins, including the tubular endosome scaffold MICAL-L1; its interaction partner and endosomal fission modulator, EH domain containing 1 (EHD1); and a host of SNX proteins that mediate endosomal cargo sorting. The retromer also links to the actin cytoskeleton via the WASH complex. Our laboratory has been focusing on an overall understanding of the mechanisms by which endocytic regulatory proteins function both in endocytic pathways and in non-endocytic trafficking. Our primary expertise is in biochemistry and molecular cell biology coupled with advanced light microscopy, but we recognize the need to incorporate in vivo components into our approach and have ongoing collaborations with other groups to examine these processes in whole organisms, including zebrafish and worms. In our studies, we will address significant and as-yet-unresolved biological problems such as: 1) how endosomal fission is regulated and linked to sorting and recycling and 2) how key endocytic proteins mediate the biogenesis of the primary cilium.

项目概要/摘要 受体的内化和再循环是所有真核细胞的关键生物过程。这 早期/分选内体是从质膜 (PM) 内化的受体的最初目的地。这 内体是一个主要的分选站，受体从这里分流到晚期内体， 溶酶体进行降解，或通过囊泡和蛋白质的短暂网络再循环回 PM 管状回收内体。而十年前，大多数研究人员认为主动排序指导 蛋白质降解途径，针对回收途径被认为在很大程度上是一种被动的 默认情况下发生的过程。然而，最近的证据支持通过以下方式对回收途径进行主动分类： 特异性分选连接蛋白 (SNX) 和其他与受体细胞质尾部结合的蛋白质，特别是 将它们作为回收目标。尽管回收是所有哺乳动物细胞的一个重要过程，但其复杂性 人们对调节知之甚少，包括内体膜上受体的分类、出芽和 囊泡和小管从内体分裂，以及受体转运回 PM。因此，我们的 对内体功能的了解远远落后于对受体内化机制的了解。一把钥匙 控制内体分选和运输的一组调节蛋白是逆转录酶复合物。 最初在从内体到高尔基复合体的生物合成货物的检索中发现了逆转录体 最近涉及细胞内外多种关键细胞途径的调节 内吞运输的范围，包括内吞再循环、线粒体稳态、中心体循环 和纤毛发生。逆转录酶复合物还与其他关键的内吞调节蛋白相互作用，包括 管状内体支架MICAL-L1；它的相互作用伙伴和内体裂变调节剂，EH 结构域 含有 1 (EHD1)；以及许多介导内体货物分类的 SNX 蛋白。逆行者还 通过 WASH 复合物与肌动蛋白细胞骨架连接。我们实验室一直致力于整体 了解内吞调节蛋白在内吞途径中发挥作用的机制 以及非内吞性贩运。我们的主要专业知识是生物化学和分子细胞生物学 先进的光学显微镜，但我们认识到需要将体内成分纳入我们的 方法并与其他小组持续合作，以检查整个生物体中的这些过程， 包括斑马鱼和蠕虫。在我们的研究中，我们将解决重要且尚未解决的生物学问题 问题例如：1）内体裂变如何被调节并与分类和回收联系起来，2）如何关键 内吞蛋白介导初级纤毛的生物发生。