MUTANTS WITH DEFECTS IN ENDOCYTIC FUNCTION

内吞作用是真核细胞中的一个基本过程，对于细胞的增殖和分化具有重要意义。 各种各样的细胞功能，从获得某些 营养素，调节细胞功能，包括胆固醇合成 与心脏病中的动脉粥样硬化斑块形成有关，以及 免疫系统产生抗体的反应。 整体 这个提议的目的是为了更好地理解基本的分子事件 内吞过程的基本步骤。 我们的方法是 哺乳动物细胞的温度敏感突变体， 内吞作用的一些方面，然后研究突变细胞， 关于有缺陷的特定事件的信息。 在特定 目的一，我们提出了各种生理和形态学研究， 在体内表征突变体，称为V.24.1，其具有缺陷 在缺陷处的溶酶体。 此外，我们计划采用体外方法， 研究突变细胞中的蛋白质靶向。 具体目标二 包括研究另外两种突变体之间的体外互补作用， 在核内体酸化方面有缺陷。 具体目标三， 我建议进一步描述另一个突变体，称为42.2，具有 影响内吞作用的不确定的病变。 具体目标四涉及使用 我们发明了一种新技术， 影响内吞囊泡早期步骤的温度敏感性损伤 阵

Endocytosis is a fundamental process in eukaryotic cells important for a variety of cellular functions ranging from the acquisition of certain nutrients, regulation of cell function, including cholesterol synthesis related to atherosclerotic plaque formation in heart disease, and response of the immune system in antibody production. The overall objective of this proposal is to better understand basic molecular events underlying steps of the endocytic process. Our approach is to isolate temperature-sensitive mutants of mammalian cells that are defective in some aspect of endocytosis and then study the mutant cells to gain information about the specific events that are defective. In specific aim one, we propose a variety of physiological and morphological studies in vivo to characterize a mutant, termed V.24.1, that has defective lysosomes at the defect. In addition, we plan an in vitro approach to investigating protein targeting in the mutant cells. Specific aim two involves studying in vitro complementation between two other mutants that are defective in endosomal acidification. In specific aim three we propose to further characterize another mutant, termed 42.2, that has an undefined lesion affecting endocytosis. Specific aim four involves using a new technique we have devised to isolate mutants expressing temperature-sensitive lesions affecting early steps of endocytic vesicle formation.