Flagellar Glycoprotein Dynamics and Whole Cell Locomotion

这项研究的目的是了解发生在细胞表面的力传递的机制，该机制负责整个细胞的运动。鞭毛膜糖蛋白(尤其是一对350 kDa刀豆蛋白A结合糖蛋白)在鞭毛膜平面内的运动参与了真核藻细胞衣藻的整个细胞滑动运动。鞭毛膜糖蛋白的交联会触发跨膜信号通路，激活鞭毛内负责350 kDa糖蛋白在鞭毛膜平面内移动的机制。实验旨在分析钙、cAMP、cGMP和蛋白质磷酸化在鞭毛跨膜信号通路中的作用。将确定鞭毛表面糖蛋白是否需要交联来激活跨膜信号通路，以及交联剂是否导致鞭毛膜糖蛋白与潜在细胞骨架(轴丝)更紧密地结合。我们建议建立一个体外模型系统来重新激活鞭毛表面的运动性，并利用这个系统来理解跨膜信号转移力的产生。将努力确定和表征负责鞭毛膜糖蛋白动力学和滑行运动的马达组件。了解细胞控制质膜蛋白分布和主动改变这些蛋白分布的机制，对于理解高等生物和单细胞藻类的功能具有重要意义。

The goal of this research is to understand the mechanism involved in force transduction occurring at the cell surface that is responsible for whole cell locomotion. The movement of flagellar membrane glycoproteins (in particular, a pair of 350 kDa concanavalin A-binding glycoproteins) within the plane of the flagellar membrane are involved in the whole cell gliding locomotion exhibited by the eukaryotic algal cell Chlamydomonas. Crosslinking of the flagellar membrane glycoproteins triggers a transmembrane signaling pathway that activates intraflagellar machinery responsible for movement of the 350 kDa glycoproteins within the plane of the flagellar membrane. Experiments are proposed to analyze the roles of calcium, cAMP, cGMP and protein phosphorylation in the transmembrane signaling pathway in the flagellum. It will be determined whether crosslinking of flagellar surface glycoproteins is necessary to activate the transmembrane signaling pathway and whether the crosslinking results in a tighter association of flagellar membrane glycoproteins with the underlying cytoskeleton (axoneme). Experiments are proposed to develop an in vitro model system for reactivating flagellar surface motility and to exploit such a system to understand the transmembrane signaling the generation of force for glycoprotein movement. Efforts will be made to identify and characterize the components of the motor responsible for flagellar membrane glycoprotein dynamics and gliding motility. Understanding the mechanisms by which cells control the distribution of plasma membrane proteins and by which they actively change the distribution of these proteins will have significance for understanding the functioning of higher organisms as well as unicellular algae.