MOLECULAR GENETICS OF INTRACELLULAR PROTEIN TRANSPORT

描述：分泌途径中沿着的膜结合细胞器 负责将新制造的蛋白质和膜输送到细胞 面 在途径的每一步，蛋白质（货物）被包装 从供体细胞器的细胞膜上长出小泡。 融合 这些具有适当靶膜的囊泡将这种货物递送到 下一个细胞器 申请人提出了以下实验： 酵母，酿酒酵母，提供分子解释 ER膜上的囊泡构建、货物选择和包装成 这些囊泡 申请人以前的工作已经证明了具体的 蛋白质之间的结合相互作用是外套的一部分， 包裹着被称为COPII的囊泡，这些囊泡将蛋白质从ER运送到 高尔基体，他们已经绘制了每个伴侣的区域， 这些蛋白质是相互作用所必需的。 这些发现表明 大的膜结合蛋白Sec 16是支架， 被膜由可溶性蛋白质复合物构成。 阐明本 在包被组装的机制中，单个蛋白质-蛋白质缔合将被 分析并用于测试每种关联如何依赖于其他关联。 的 小的GTSAr 1 p在COPII复合物组装中的作用也将被 评估。 纯化的蛋白质组装体将通过电子显微镜检查。 用显微镜观察生物化学相互作用是如何产生被膜结构的。 申请人最近发现了几种新的基因， 货物分子被包装到囊泡中， 这个包装。 提出了实验来探索的机制（S） 选择及其与囊泡被膜形成的关系。 囊泡运输的分子机制似乎是 在酵母和哺乳动物中也是如此。 通过在酵母中研究这一过程， 分子遗传学和生物化学可以用来识别 控制分泌的基本机制和关键基因产物。 对疾病的潜在应用包括囊性纤维化、肺 肺气肿，以及挑战膜包膜病毒生长的方法 以及肿瘤细胞不受控制的生长。

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.