Molecular mechanisms that regulate vesicle formation and transport

项目总结 如何配置和维持真核细胞的胞内膜系统是一个基本的问题 细胞生物学中的问题。这种组织的缺陷往往会导致疾病。我的首要目标是 实验室将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运输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 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，我们的研究 关注蛋白质和脂肪从内质网输出所必需的两条基本运输途径 (ER)和蛋白质在溶酶体内通过多囊泡内小体(MVE)中间体的周转。基因突变 调节这些过程的几个因素被认为与癌症、糖尿病、免疫功能障碍、 和神经退化。因此，破译ER出口管制的基本原则 而MVE的生物发生应该有助于未来确定疾病干预的治疗靶点。一 我的主要研究重点是阐明早期分泌途径是如何组织的。我们的发现 揭示了存在一个保守的膜界面，它连接着内质上的亚域 产生COPII涂层运输载体到并列的ER-Golgi中间隔室的网状物(ER) (ERIGIC)。我们发现Trk融合基因(TFG)是这个界面的关键成分，并表明它的 抑制使ER和ERGIC膜解偶联并导致COPII涂层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其机制。 它引导微血管的形成，使腔内小泡(ILV)进入其内部进行隔离。 细胞质中与膜相关的物质。巨噬细胞与溶酶体的最终融合导致 ILV及其相关蛋白的降解，这在抑制肿瘤中发挥关键作用 信号受体的捕获和隔离。利用线虫，我们已经开发出一种高度简化的新的， 和遗传上易处理的系统来研究内体分选复合体的成分如何需要 运输(ESCRT)机械使内吞的货物能够在以下情况下移动到MVE和ILV 完好无损的发育中的动物。我们未来的工作将继续利用不断发展的方法，以进一步 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控的。更好的 对这些过程的理解将对维持正常蛋白质的动态平衡控制产生关键的见解 在细胞增殖和分化过程中，分泌和内吞途径的运输。

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.