RUI: Signal Coupling During Endocytosis in Amoeba Proteus

本研究的主要目的是继续对变形虫胞吞起始过程中的信号耦合机制进行基础研究，并为一些本科生提供实际的研究经验。胞吞作用是一个基本的过程，它包括通过表面膜内折叠和囊泡吸收细胞外的物质。该实验室之前的工作检查了信号分子与细胞表面的相互作用，并确定了与内吞作用发生相关的信号通路的几个可能组成部分。这些物质包括G蛋白、环AMP和钙。在霍乱和百日咳毒素存在的情况下，通过膜蛋白的adp核糖基化鉴定了变形虫膜中的g蛋白。在受刺激的细胞中，吞噬作用和胞饮作用的启动引起细胞质cAMP水平的快速瞬态振荡和细胞质Ca的瞬态增加。本提案将试图进一步表征信号通路的组成部分，并试图区分在胞饮作用和吞噬作用中发生的信号过程。阿米巴是研究内吞作用的一个特别有用的模型系统，期望这项研究将增加我们对阿米巴和其他系统内吞作用机制的了解。

The major objectives of this proposed research are to continue basic investigations into the mechanism of signal-coupling during the initiation of endocytosis in Amoeba proteus and to provide some undergraduate students with a realistic research experience. Endocytosis is a fundamental process which involves the uptake of material external to a cell by surface membrane infolding and vesiculation. Previous work from this laboratory examined the interaction of signal molecules with the cell surface and identified several possible components of the signal pathway associated with the onset of endocytosis. These include a G- protein, cyclic AMP and calcium. A G-protein in the amoeba membrane was identified by ADP-ribosylation of a membrane protein(s) in the presence of cholera and pertussis toxin. Initiation of both phagocytosis and pinocytosis elicit rapid transient oscillations in cytoplasmic cAMP levels and cytoplasmic Ca increases transiently in stimulated cells. This proposal will attempt to further characterizethe components of the signal pathway and try to differentiate between the signal processes occurring during both pinocytosis and phagocytosis. The ameba represents a particularly useful model system in the study of endocytosis and it is expected that this study will increase our insight into the mechanism of endocytosis in this and other systems.