MOLECULAR STUDIES OF EUKARYOTIC CELL SURFACE GROWTH

蛋白质分泌是一个从根本上保守的过程，它提供了 细胞产生稳定的细胞内隔间的机制，如 内质网、高尔基体、溶酶体和质膜，并与 外部细胞和组织。一种基因、分子克隆和 酿酒酵母HAS中这一过程的生化分析 发现了所有真核生物共有的基因和机制。 这项提案开辟了一条新的调查路线，涉及 经高尔基池转运囊泡形成机制的研究 以及囊泡运输到胞质分裂沟的途径 在酵母细胞周期的早期形成。 已有证据表明，运输囊泡有多种途径 由反高尔基形成，其中至少有一个涉及囊泡 在到达细胞表面的过程中通过内体的交通。遗传和 细胞分级分析建议将分泌物与已知的 对内体进行分选的途径，以发现参与的新基因 来自高尔基山脉的萌芽，并使用生化分析来澄清 网状蛋白在萌发途径之一中的作用。 某些膜酶通过内吞体内运输到 新生的分裂隔膜，它们参与形成细胞壁 标志酵母萌芽部位的结构(几丁质环) 在细胞周期的早期。肌动蛋白转运的途径和调控 我们将检查从内体到新生隔膜的这些酶。 为了了解这一关键的机制和细胞周期控制 进程。 对酵母细胞中这些过程的研究揭示了基本原理 人类细胞共有的细胞和细胞器生长的各个方面。 此外，这一知识的应用使生物技术 和制药公司利用酵母细胞表达和 分泌商业数量的重要荷尔蒙，血液蛋白， 生长因子和病毒抗原。

Protein secretion is a fundamentally conserved process that provides a mechanism for cells to create stable intracellular compartments such as the ER, Golgi, lysosome, and plasma membrane, and to communicate with external cells and tissues. A genetic, molecular cloning, and biochemical analysis of this process in Saccharomyces cerevisiae has uncovered genes and mechanisms that are shared among all eukaryotes. This proposal develops a new line of investigation concerning the mechanism of transport vesicle formation from the trans Golgi cisterna and of the pathway of vesicle traffic to the cytokinesis furrow which forms early in the yeast cell cycle. Evidence has emerged to suggest multiple paths of transport vesicle formation from the trans Golgi, at least one of which involves vesicular traffic through the endosome en route to the cell surface. Genetic and cell fractionation analysis is proposed to relate secretion to the known pathway of sorting to the endosome, to discover new genes involved in budding from the Golgi, and to use biochemical analysis to clarify the role of clathrin in one of the budding pathways. Certain membrane enzymes are transported through the endosome to the nascent division septum where they participate in forming a cell wall structure that marks the site of yeast bud emergence (the chitin ring) early in the cell cycle. The pathway and regulation of transport of these enzymes from the endosome to the nascent septeum will be examined to understand the mechanism and cell cycle control of this essential process. The study of these processes in yeast cells has illuminated fundamental aspects of cell and organelle growth that are shared by human cells. Furthermore, the application of this knowledge has allowed biotechnology and pharmaceutical companies to harness yeast cells to express and secrete commercial quantities of important hormones, blood proteins, growth factors, and viral antigens.