植物小G蛋白功能的研究进展

近年来,小G蛋白的调控途径已经成为人们研究细胞信号转导过程的热点问题.小G蛋白家族包括Ras、Rab、Rho、Arf和Ran亚家族,它们起着许多不同的重要细胞生理作用,例如基因表达、细胞骨架重组装、微管的形成以及囊泡和核孔运输机制.这些小G蛋白作为重要的分子开关,具有一个非常保守的功能区域,即I-Ⅳ结构区,它起着关键性作用.从拟南芥(Arabidopsisthaliana)基因组预测分析得出,拟南芥含有93个小G蛋白同源序列,包含Rab、Rho、Arf和Ran亚家族,但没有Ras亚家族.本文主要阐述了迄今在植物中研究小G蛋白各个亚家族功能的最新进展,并对植物、酵母和动物相关的同 源蛋白的生理功能进行比较和推测.

Current Progress on the Small GTPase Gene Superfamily in Plants

In recent years, small G proteins have become an intensively studied group of regulatory GTP hydrolyses involved in cell signaling. The small G-protein superfamily includes Ras, Rho, Rab, Arf and Ran homologs, which take part in numerous and diverse cellular processes, such as gene expression, cytoskeletal reorganization, microtubule organization, and vesicular and nuclear transport. These proteins, functioning as molecular switches, share a common structural core, described as the I-IV domain, and significant sequence similarity. The Arabidopsis genome contains 93 genes that encode small GTP-binding protein homologs. Phylogenetic analysis of these genes shows that plants contain Rab, Rho, Arf, and Ran GTPase but not Ras GTPase. In this paper, we review the known functions of individual members of these small GTPases in plants. Additionally, we describe the possible roles of these GTPases in relation to their similarity to orthologs with known functions in yeast or animal systems.