Tensegrity: a model for cellular contractility

生命系统最迷人和最重要的特性之一是它们科普物理损伤的能力。 这种特性在单细胞和多细胞系统中都有体现，并且不仅在许多不同的动物门中广泛保守，而且在植物中也是如此。 由于其明显的临床重要性，多细胞伤口愈合长期以来一直是密切关注的主题。 相比之下，直到最近，单细胞中质膜创伤的修复一直被忽视。 至少有两种机制已经被描述：一个非常快速的膜融合事件，提供了一个即时的块涌入的离子，否则会杀死细胞，和一个较慢的收缩反应，其中一个圆周环的肌动蛋白和肌球蛋白组装周围的伤口和关闭。 拟议的研究计划的主要目标是表征的机制，调节装配和关闭的瞬态收缩阵列。 使用非洲爪蟾卵母细胞作为模型系统，结合物理，显微镜，和重组DNA为基础的方法将被用来测试细胞张力，局部增加的上游调节肌动蛋白和肌球蛋白-2，和细胞内钙之间的关系，在招聘肌动蛋白丝和肌球蛋白-2瞬态收缩阵列。 虽然单细胞伤口修复本身就是一个重要的过程，但该项目的基本假设是收缩性环伤口反应的重要性远远超出了单细胞。

One of the most fascinating and important properties of living systems is their ability to cope with physical damage. This property is manifested in both single cells and multicellular systems and is broadly conserved not only in a number of different animal phyla, but in plants as well. Because of it obvious clinical importance, multicellular wound healing has long been the subject of intense scrutiny. Repair of plasma membrane wounds in single cells, in contrast, has been overlooked until recently. At least two mechanisms have been described: an extremely rapid membrane fusion event that provides an immediate block to the inrush of ions that would otherwise kill the cell, and a slower contractile response in which a circumferential ring of actin and myosin assembles around the wound and closes. The primary goal of the proposed research program is to characterize the mechanisms that regulate assembly and closure of transient contractile arrays. Using Xenopus oocytes as a model system, a combination of physical, microscopic, and recombinant DNA-based approaches will be employed to test the relationships between cell tension, local increases in the upstream regulators of actin and myosin-2, and intracellular calcium, in the recruitment of actin filaments and myosin-2 to transient contractile arrays. While single cell wound repair is an important process in its own right, the fundamental assumptions that underlie this project is that the importance of the contractile ring wound response extends well beyond the single cell.