YEAST LATE GOLGI MEMBRANE PROTEIN RETENTION

这项建议中概述的研究针对的是一般 膜蛋白如何正确分类和定位的问题 特定的真核细胞细胞器。细菌的生物发生与维持 细胞器，一个知之甚少的过程，依赖于正确的定位 以及膜蛋白的保留，对细胞的正常功能至关重要。 此外，人类的几种疾病(如囊性纤维化和家族性 高胆固醇血症)是由于膜的分选缺陷引起的 蛋白质。虽然已经确定了许多膜蛋白分选事件 在真核细胞中，对负责 识别和定位膜蛋白到正确的细胞 车厢。 这项提案描述了一种多方面的方法来表征 高尔基体保留其驻留高尔基体膜的机制 蛋白质。这一分析已经在酵母中进行，酿酒酵母， 因为这种真核生物很容易受到遗传学的影响。已故的 高尔基酶，二肽基氨基肽酶(DPAP)A，已被证明是 在它的细胞质区域中包含一个保留信号，它既是 对于其在高尔基体中的本地化来说是必要的和充分的。在……里面 为了识别识别这个信号的细胞机械和 将DPAP A保留在高尔基体中，已经开发出一种基因筛查 鉴定未能正确保留高尔基膜的突变体 蛋白质。迄今发现的grd(高尔基保持缺陷)突变体 分为10个互补组。对该系统的作用的阐明 单个grd基因产物对高尔基体膜蛋白的保留作用 承诺阐明高尔基体保留机制，特别是可以 为识别DPAP A保留信号提供依据 受体。独立的遗传和生化方法也将是 更直接地专注于保持信号的识别 受体。通过实验确定留存是否发生在 还将从高尔基之后的隔间中进行回收。这个 这些研究的结果应该有助于阐明酵母的作用机制 高尔基体膜蛋白保留率和显著增加我们的整体 膜蛋白分选知识。

The research outlined in this proposal is directed towards the general question of how membrane proteins are properly sorted and localized to specific eukaryotic cellular organelles. The biogenesis and maintenance of organelles, a poorly understood process dependent on correct localization and retention of membrane proteins, is critical for proper cell function. In addition, several human diseases (e.g. cystic fibrosis and familial hypercholesterolaemia) arise due to defects in the sorting of membrane proteins. While many membrane protein sorting events have been identified in eukaryotic cells, little is known of the machinery responsible for recognizing and localizing membrane proteins to the correct cellular compartment. This proposal describes a multi-faceted approach to characterize the mechanism by which the Golgi apparatus retains its resident Golgi membrane proteins. This analysis has been conducted in the yeast, S. cerevisiae, because this eukaryotic organism is easily amenable to genetics. The late Golgi enzyme, dipeptidyl aminopeptidase (DPAP) A, has been shown to contain a retention signal it its cytoplasmic domain which is both necessary and sufficient for its localization in the Golgi apparatus. In order to identify the cellular machinery that recognizes this signal and retains DPAP A in the Golgi, a genetic screen has been developed to identify mutants which fail to properly retain their Golgi membrane proteins. The grd (Golgi retention defective) mutants identified thus far fall into 10 complementation groups. The elucidation of the role of the individual grd gene products in the retention of Golgi membrane proteins promises to illuminate the Golgi retention mechanism and in particular may provide the basis for identification of the DPAP A retention signal receptor. Independent genetic and biochemical approaches will also be pursued that more directly focus on identification of the retention signal receptor. Experiments to determine whether or not retention occurs via retrieval from a post-Golgi compartment will also be performed. The results of these studies should help illuminate the mechanism of yeast Golgi membrane protein retention and add significantly our overall knowledge of membrane protein sorting.