Elucidation of the organization mechanism of dynamic higher-ordered structures in biological cells

本计画之题目为生物细胞中动态高阶结构之组织机制之阐明。在这里，术语“动态高级结构”主要指真核细胞中的膜结合的细胞器，而“阐明组织机制”则意味着深入了解它，以便在人工条件下重建细胞器。由于细胞内膜系统的动力学行为可以通过考虑它们与非膜高级结构的相互作用来理解，因此本项目包括许多类型的研究课题。除了细胞内膜系统（质膜、核膜、线粒体内膜、叶绿体类囊体膜、肌细胞肌浆网、视杆细胞盘膜、神经元突触囊泡）、非膜高级结构（细胞膜，真核鞭毛，肌丝），特殊的高级结构（病毒、细菌鞭毛马达、全细菌紫膜）和人工脂膜。我们每年举行一次会议，要求项目的每个成员报告他的研究成果以及相关研究领域的当前主题。如此多的发现被呈现出来，观众们很满意听到其他领域正在发生的事情。报告了重组某些特定的高级结构的试验，但大部分报告涉及在分子水平上阐明生物现象。指出在细胞水平上对生物学现象进行富有成效的讨论之前，应发展相关的物理化学方法来分析细胞内高阶结构的复杂耦合行为。我们希望重组细胞内更高层次结构的挑战将导致未来更重要的发现。

The title of this project is elucidation of the organization mechanism of dynamic higher-order structures in biological cells. Here the term "dynamic higher-ordered structures" means mainly membrane-bounded organella in eucaryotic cells, and "elucidation of the organization mechanism" means to understand it so deeply as to reconstitute the organella under artificial conditions. Since dynamic behaviors of intracellular membranous systems can be understood by taking account of their interactions with non-membranous higher-ordered structures, many types of research subject are included in this project. Besides intracellular membrane systems (plasma membrane, nuclear membranes, the inner membrane of mitochondria, the thylakoid membrane of chloroplasts, the sarcoplasmic reticulum of muscle cells, the disk membrane of photoreceptor rod cells, the synaptic vesicle of neurons), non-membrane higher-ordered structures (the cytoskelton, eucaryotic flagella, muscle filaments), special higher-ordered structures (virus, the bacterial flagella motor, the purple membrane of holobacteria) and artificial lipid membranes were studied. We held annual meetings, in which each member of the project was asked to report his research output as well as current topics in a related research field. So many discoveries were presented, and the audience were satisfied to hear what was going on in other fields. Trials to reconstitute some specific higher-ordered structures were reported, but a large fraction of the reports concerned elucidation of biological phenomena at the molecular level. It is pointed out that relevant physicochemical methods for analyzing complicatedly-coupled behaviors of intracellular higher-ordered structures should be developed before achieving fruitful discussion about biological phenomena at the cellular level. We hope that the challenge to reconstitute intracellular higher-ordered structures will lead to production of more important discoveries in future.