Molecular machinery of the macropinosome and phagosome formation.

巨胞饮体和吞噬体形成的分子机制。

基本信息

批准号：
09670017
负责人：
ARAKI Nobukazu
金额：
$ 2.11万
依托单位：
Kagawa Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Macrophages show active macropinocytosis and phagocytosis which are F-actin-dependent cell motilities to take up extracellular solute and particles such as bacteria, respectively. These cell motilities also require a variety of actin-binding proteins which regulate F-actin polymerization, depolymerization and rearrangement. In order to elucidate the molecular machinery of macropinocytosis and phagocytosis, we have surveyed the involvement of several actin-binding proteins in macropinocytosis and phagocytosis, and revealed functional contributions of some of them. In this study, we have identified a myosin-mediated contractile activity that closes phagocytic cups into intracellular phagosomes in macrophages. It was shown that only myosin lc localized on the distal margin of the phagocytic cup, although other classes of myosins also distributed around phagocytic cups and/or phagosomes.Then, we developed a new application of the fluorescence ratio imaging technique to in situ demonstration of the functional relationship between two related molecules such as F-actin and an actin-binding protein. Using this ratio imaging technique, we revealed that actinin-4, a novel isoform of alpha-actinin, was preferentially localized in circular ruffles, early macropinosomes in macrophages. These findings suggest that F-actin-bundling by actinin-4 may be functionally associated with macropinosomes formation and maintenance.Furthermore, we are now continuing studies on other F-actin-binding proteins such as cofilin and ERM proteins.

巨噬细胞分别表现出活跃的大胞刺和吞噬作用，分别是F-肌动蛋白依赖性细胞的运动性，分别吸收细胞外溶质和细菌等颗粒。这些细胞运动还需要各种调节F-肌动蛋白聚合，解聚和重排的肌动蛋白结合蛋白。为了阐明大细胞增多症和吞噬作用的分子机制，我们调查了几种肌动蛋白结合蛋白参与大型细胞增多症和吞噬作用，并揭示了其中一些肌动蛋白的功能贡献。在这项研究中，我们确定了肌球蛋白介导的收缩活性，该活性将吞噬杯关闭到巨噬细胞中细胞内吞噬体中。 It was shown that only myosin lc localized on the distal margin of the phagocytic cup, although other classes of myosins also distributed around phagocytic cups and/or phagosomes.Then, we developed a new application of the fluorescence ratio imaging technique to in situ demonstration of the functional relationship between two related molecules such as F-actin and an actin-binding protein.使用该比率成像技术，我们透露肌动蛋白4是一种新型的α-肌动蛋白的同工型，优先定位在圆形荷叶边，早期的大斑点体中的巨噬细胞中。这些发现表明，肌动蛋白4的F-肌动蛋白在功能上可能与大型体体的形成和维持相关。FURTHERMORE，我们现在正在继续研究其他F-肌动蛋白结合蛋白，例如Cofilin和ermer蛋白。