Rho小G蛋白介导的细胞周期调控

Rho小G蛋白作为一个信号分子家族具有多样化的功能, 可以调节细胞骨架重排 、细胞迁移、细胞极性、基因表达、细胞周期调控等. Rho小G蛋白家族对细胞周期 调控的研究主要集中在其对于有丝分裂期细胞的调节作用，包括调节有丝分裂期前 期细胞趋圆化、后期染色体排列及收缩环的收缩作用.近期的研究显示,Rho小G蛋白及其效应分子对于细胞周期G1、S、G2期的调控主要是通过影响细胞周期的正调控因子细胞周期蛋白D1 (cyclin D1) 和负调控因子细胞周期蛋白依赖型激酶相互作用蛋白1及细胞周期蛋白依赖型激酶抑制蛋白27 (p21cip1/p27kip1) 进行的.本文总结了Rho小G蛋白及其效应分子在细胞周期调控,尤其是对G1/S期调控的研究进展，并简要阐述了Rho小G蛋白介导的细胞周期调控异常与癌症发生的关系.

The Roles of Small Rho GTPases in Cell Cycle Regulation

The small Rho GTPases cycle between GDP-bound inactive forms and GTP-bound active form, and act as the molecular switches to regulate the processes of actin cytoskeleton dynamics, cell migration, cell motility, cell polarization, gene expression and control of cell cycles. The proliferation of eukaryotic cells is a tightly regulated process in which the cells sense both of intracellular and extracellular environments in each cell-cycle phases. Rho GTPases and their effectors are able to regulate the cell-cycle regulation at all of the G1, S, G2 and M phases, to mediate the G1/S transition, cell rounding at mitosis onset, chromosomal alignment and actomyosin ring contraction at the end of mitosis. Here, we summarized the current understanding about the roles of Rho GTPases in cell-cycle regulation focusing on specific members of the Rho family and their downstream effectors, such as cyclin D1, p21cip1 and p27kip1, in G1/S transition. We also discussed the connection between small Rho GTPases mediated cell-cycle regulation and cancers.