MOLECULAR GENETICS OF INTRACELLULAR PROTEIN TRANSPORT

描述：沿分泌途径的膜结合细胞器。 负责将新生成的蛋白质和膜输送到细胞 浮出水面。在路径上的每一步，蛋白质(货物)都被包装 进入囊泡，这些囊泡从供体细胞器的膜上发芽。融合 这些带有适当靶膜的囊泡将这些货物运送到 途径中的下一个细胞器。申请者提出了在 酵母菌，酿酒酵母，为 在ER膜上构建囊泡，挑选货物并包装成 这些水泡。申请人之前的工作已经证明了具体的 作为外壳一部分的蛋白质之间的结合相互作用 包裹被称为COPII的囊泡，它将蛋白质从内质网运送到 高尔基体，他们绘制了每个伙伴的区域 对相互作用至关重要的蛋白质。这些发现表明 大的膜结合蛋白Sec16是细胞生长的支架 涂层是由可溶性蛋白质复合体构成的。为了澄清 涂层组装的机制，单独的蛋白质-蛋白质结合将是 分析并用于测试每个关联是如何依赖其他关联的。这个 小GTP酶Sar1p在COPII复合体组装中的作用也将是 已评估。纯化蛋白质的组装将用电子手段进行检查。 显微镜观察生物化学相互作用如何产生皮毛结构。 申请者最近发现了几个新的基因，这些基因决定了 货物分子被包装在泡囊中，总体选择性 那个包装。建议进行实验以探讨其作用机制(S)。 选择及其与囊泡被形成的关系。 囊泡运输的分子机制似乎是 酵母和哺乳动物也是如此。通过在酵母中研究这一过程，充分发挥了 分子遗传学和生物化学的研究成果可以用来鉴定 控制分泌的基本机制和关键基因产物。 潜在的疾病应用包括囊性纤维化，肺 肺气肿和挑战膜包膜病毒生长的方法 可能还有肿瘤细胞的不受控制的生长。

DESCRIPTION: The membrane-bounded organelles along the secretory pathway are responsible for delivering newly made protein and membrane to the cell surface. At each of the steps on the pathway, protein (cargo) is packaged into vesicles that bud from the membrane of the donor organelle. Fusion of these vesicles with the appropriate target membrane delivers this cargo to the next organelle in the pathway. The applicant proposes experiments in the yeast, Saccharomyces cerevisiae, to provide molecular explanations for vesicle construction at the ER membrane, cargo selection and packaging into these vesicles. Previous work from the applicant has demonstrated specific binding interactions between the proteins that are part of the coat that encapsulates the vesicles, known as COPII, that carry protein from the ER to the Golgi apparatus, and they have mapped the regions in each partner protein that are essential for the interactions. Those findings suggest that the large membrane-bound protein Sec16 is the scaffold onto which the coat is constructed from soluble protein complexes. To elucidate the mechanism of coat assembly, individual protein-protein associations will be assayed and used to test how each association depends on the others. The role of the small GTPase Sar1p in assembly of the COPII complex will also be evaluated. Assemblies of purified proteins will be examined by electron microscopy to see how the biochemical interactions generate coat structures. The applicant has recently discovered several new genes that determine which cargo molecules are packaged into vesicles and the overall selectivity of that packaging. Experiments are proposed to probe the mechanism(s) of selection and their relation to vesicle coat formation. The molecular mechanisms underlying vesicular transport appear to be the same in yeast and mammals. By studying this process in yeast the full power of molecular genetics and biochemistry can be used to identify the fundamental mechanisms and key gene products that control secretion. Potential applications to disease include Cystic Fibrosis, pulmonary emphysema, and ways to challenge the growth of membrane enveloped viruses and possibly the uncontrolled growth of tumor cells.