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Analysis of the molecular mechanism of the novel topological transformation of membrane vesicle and the construction of the cell-model

膜囊泡新型拓扑转化的分子机制分析及细胞模型构建

基本信息

批准号：
13480218
负责人：
HOTANI Hirokazu
金额：
$ 8.9万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

(1) Liposome manipulation. The morphologies of living cells are based on the mechanical characteristics of cytoskeleton and membrane. To investigate the role of lipid membrane in the morphogenesis, we manipulated the giant liposomes that encapsulated two polystyrene beads by using double beam laser tweezers. As mechanical force was applied onto the beads to push a liposome membrane from inside, a spherical liposome transformed into a lemon shape with increasing the tension, and subsequently a tubular membrane projection was generated at the end of the lemon-shaped liposome. In an elongation stage of the lemon shape, the force required for the transformation became larger. Just before a membrane tube was generated, the force reached the maximum strength. However, after the membrane tube was developed, the force suddenly decreased, and kept constant strength independently from the tube length. These results indicate that lipid membrane can form the membrane tube by simple applying of mechanical force.(2) Cell model developed with giant liposome. It is well established that many kinds of actin binding proteins play regulatory roles in the organization of actin networks in living cells. To study such organization roles, we characterized the transformation of liposomes encapsulating actin with its crosslinking proteins, fascin, a-actinin or filamin. As the actin polymerized, which caused various morphological changes of liposomes. The differences in morphology indicate that the actin-crosslinking proteins actually determine liposome shape by organizing their specific actin networks.

(1)脂质体操作。活细胞的形态是基于细胞骨架和细胞膜的力学特性。为了研究脂质膜在形态发生中的作用，我们用双光束激光镊子操纵包裹两个聚苯乙烯珠的巨大脂质体。当向珠上施加机械力以从内部推动脂质体膜时，随着张力的增加，球形脂质体转变为柠檬形，随后在柠檬形脂质体的末端产生管状膜突起。在柠檬形状的伸长阶段，转变所需的力变得更大。在即将形成膜管的时候，力量达到了最大。然而，在膜管开发后，力突然下降，并保持恒定的强度独立于管的长度。这些结果表明，脂质膜可以通过简单的机械力的施加形成膜管。(2)用巨脂质体建立细胞模型。许多肌动蛋白结合蛋白在活细胞中肌动蛋白网络的组织中起着调节作用。为了研究这种组织的作用，我们的特点是转化的脂质体封装肌动蛋白与其交联蛋白，肌成束蛋白，α-辅肌动蛋白或细丝蛋白。随着肌动蛋白的聚合，脂质体的形态发生了各种变化。形态上的差异表明肌动蛋白交联蛋白实际上通过组织其特定的肌动蛋白网络来决定脂质体的形状。