Molecular mechanisms that regulate vesicle formation and transport

项目摘要 真核细胞的细胞内膜系统是如何构成和维持的， 细胞生物学的问题。这个组织的缺陷往往导致疾病。我的首要目标是 实验室的目标是确定调节膜动力学的分子机制，包括囊泡 后生动物早期分泌和内吞途径中的生物发生、细胞器运输和蛋白质分选 细胞我们的目标是确定正常的膜转运如何有助于细胞内稳态，并了解 当运输途径被破坏时出现的疾病状态的分子基础。使用组合 我们的研究结合了模型系统、结构生物学、生物化学、遗传学和高分辨率亚细胞成像， 着重于蛋白质和脂质从内质网输出所必需的两个基本运输途径 (ER)和溶酶体内的蛋白质周转经由多泡内体（MVE）中间体。突变 调节这些过程的几种因素与癌症、糖尿病、免疫功能障碍 和神经退化因此，解读ER出口监管的基本原则， MVE的生物发生应有助于未来确定疾病干预的治疗靶点。一 我研究的主要焦点是阐明早期分泌途径是如何组织的。我们的研究结果 揭示了一个保守的膜界面的存在，该界面连接内质网上的亚结构域， 内质网（ER），产生COPII包被的转运载体，转运到并置的ER-高尔基体中间隔室 （ERGIC）。我们确定Trk融合基因（TFG）是该界面的关键组成部分，并表明其 抑制使ER和ERGIC膜解偶联并导致COPII包被的载体的各向同性扩散， 降低了货物分泌的效率。我的第二个研究重点是了解 引导MVEs的形成，MVEs将腔内小泡（ILV）出芽到其内部以隔离 来自细胞质的膜相关货物。MVE与溶酶体的最终融合导致 ILV及其相关蛋白质的降解，其通过控制肿瘤的生长而在肿瘤抑制中起关键作用。 捕获和隔离信号受体。利用C. elegans，我们已经开发了一种新的，高度简化的， 和遗传上易于处理的系统，以研究内体分选复合物的成分如何需要 运输（ESCRT）机械使内吞货物能够在以下情况下移动到MVE和ILV： 一个完整的，发育中的动物我们未来的工作将继续利用不断发展的方法， 确定COPII介导的转运和ESCRT介导的MVE生物发生是如何被适当调节的。更好的 对这些过程的理解将有助于深入了解维持正常蛋白质的体内平衡控制 在细胞增殖和分化过程中的分泌和内吞途径中的运输。

PROJECT SUMMARY How the intracellular membrane system of eukaryotic cells is configured and maintained is a fundamental problem in cell biology. Deficiencies in this organization often lead to disease. The overarching goal of my laboratory is to define the molecular mechanisms that regulate membrane dynamics, including vesicle biogenesis, organelle trafficking, and protein sorting in the early secretory and endocytic pathways of metazoan cells. We aim to determine how normal membrane transport contributes to cellular homeostasis and understand the molecular basis for disease states that emerge when trafficking pathways are disrupted. Using a combination of model systems, structural biology, biochemistry, genetics, and high-resolution subcellular imaging, our studies focus on two essential trafficking pathways necessary for protein and lipid export from the endoplasmic reticulum (ER) and protein turnover within lysosomes via a multivesicular endosome (MVE) intermediate. Mutations in several factors that regulate these processes have been implicated in cancer, diabetes, immune dysfunction, and neurodegeneration. Thus, deciphering the fundamental principles underlying the regulation of ER export and MVE biogenesis should facilitate the future identification of therapeutic targets for disease intervention. One major focus of my research has been elucidating how the early secretory pathway is organized. Our findings revealed the existence of a conserved membrane interface, which links subdomains on the endoplasmic reticulum (ER) that produce COPII-coated transport carriers to juxtaposed ER-Golgi intermediate compartments (ERGIC). We identified Trk-fused gene (TFG) as a key constituent of this interface and have shown that its inhibition uncouples ER and ERGIC membranes and leads to the isotropic diffusion of COPII-coated carriers, reducing the efficiency of cargo secretion. My second research focus is aimed at understanding the mechanisms that direct the formation of MVEs, which bud intralumenal vesicles (ILVs) into their interior to sequester membrane-associated cargoes from the cytoplasm. Eventual fusion of MVEs with lysosomes results in the degradation of ILVs and their associated proteins, which plays a key role in tumor suppression by governing the capture and sequestration of signaling receptors. Using C. elegans, we have developed a new, highly simplified, and genetically tractable system to investigate how components of the endosomal sorting complex required for transport (ESCRT) machinery enables the movement of endocytosed cargo to MVEs and ILVs in the context of an intact, developing animal. Our future work will continue to capitalize on evolving methodologies to further establish how COPII-mediated transport and ESCRT-mediated MVE biogenesis are properly regulated. A better understanding of these processes will yield key insights into the homeostatic controls that sustain normal protein trafficking in the secretory and endocytic pathways during cell proliferation and differentiation.