RUI: Signal Coupling During Endocytosis in Amoeba Proteus

本研究的主要目的是继续对变形阿米巴内吞作用启动过程中的信号偶联机制进行基础研究，并为一些本科生提供现实的研究经验。内吞作用是一个基本的过程，它涉及到细胞外物质被表膜内折叠和囊化所摄取。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开始相关的信号通路的几个可能成分。这些物质包括G蛋白、环状AMP和钙。在霍乱和百日咳毒素存在下，用膜蛋白(S)的腺苷二磷酸核糖化反应鉴定了阿米巴膜中的G蛋白。吞噬作用和吞噬作用均可引起胞浆cAMP水平的快速瞬时振荡，刺激细胞内胞浆钙瞬间升高。这一建议将试图进一步表征信号通路的组成部分，并试图区分吞噬和吞噬过程中发生的信号过程。阿米巴在内吞作用的研究中代表了一个特别有用的模型系统，预计这项研究将增加我们对该系统和其他系统中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.