权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Morphological changes of giant liposomes caused by cytoskeletal proteins, surfactants, or optical tweezers

细胞骨架蛋白、表面活性剂或光镊引起的巨型脂质体的形态变化

基本信息

批准号：
13680738
负责人：
TAKIGUCHI Kingo
金额：
$ 0.96万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
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)Liposomes are micro-compartments made of lipid bilayer membranes with characteristics quite similar to those of biological membranes. To form artificial cell-like structures, we generated liposomes that contained subunit proteins of cytoskeletons : actin, and its associating proteins. Spherical liposomes were transformed into disk-or dumbbell-shapes by the polymerization of encapsulated actin. Bipolar-or cell-like-shaped liposomes were developed by the assembly of encapsulated actin and its crosslinking proteins, fascin, -actinin, or filamin, by mechanical forces generated by the organization of internal actin-networks. Dynamic processes of morphological transformations of liposomes were visualized by high intensity dark-field light microscopy. The differences in morphology among transformed liposomes indicate that actin-crosslinking proteins determine liposome shape by organizing their specific actin networks. Morphological analysis reveals that the crosslinking manner, i.e. distance and angular flexibility between adjacent crosslinked actin filaments, is essential for the morphogenesis.2)Topological changes, such as fusion and division of membrane vesicles, play an essential role in cellular activities. To investigate the mechanism of these processes, we visualized the liposomes undergoing topological transformation induced by interactions between liposomal membranes and fusogenic peptides derived from influenza hemagglutinin, melittin, or surfactants with direct, real-time observation using high-intensity dark-field microscopy. As the results, a variety of novel topological transformations were found, including the opening-up of liposomes, the direct expulsion of inner vesicles, intermittent quakes, and inside-out topological inversion. These novel findings reveal that the lipid bilayer itself possesses the ability to undergo topological transformation.

1)脂质体是由脂类双层膜组成的微腔，其特性与生物膜非常相似。为了形成人造细胞样结构，我们产生了含有细胞骨架亚单位蛋白的脂质体：肌动蛋白及其结合蛋白。通过聚合包裹的肌动蛋白，将球形脂质体转化为圆盘状或哑铃状。利用肌动蛋白内部网络的组织产生的机械力，微囊化的肌动蛋白及其交联蛋白--肌动蛋白、-肌动蛋白或细丝蛋白组装成双极或细胞样的脂质体。用高强度暗场光学显微镜观察脂质体形态变化的动态过程。不同转化的脂质体在形态上的差异表明，肌动蛋白-交联蛋白通过组织其特定的肌动蛋白网络来决定脂质体的形状。形态分析表明，交联化方式，即相邻交联化肌动蛋白细丝之间的距离和角度柔性，是细胞形态发生所必需的。2)拓扑变化，如膜小泡的融合和分裂，在细胞活动中起着重要作用。为了研究这些过程的机制，我们使用高强度暗视野显微镜，通过直接、实时观察，显示了脂质体与来自流感血凝素、蜂毒素或表面活性物质的融合多肽之间的相互作用而引起的拓扑转化。结果发现了各种新的拓扑变化，包括脂质体的打开，内囊的直接排出，间歇性地震，以及由内向外的拓扑反转。这些新的发现揭示了脂质双层本身具有进行拓扑转换的能力。