RhoA的泛素化降解机制及功能

The Mechanisms and Functions of Ubiquitin-mediated RhoA Degradation

Rho小G蛋白(Ras homology frowth-related,Rho G)家族作为分子开关(molecular switch)在GTP结合的激活形式和GDP结合的非激活形式之间转换,发挥着重要的生物学功能,细胞内Rho小G蛋白的含量可由泛素–蛋白酶体系统(ubiquitin-proteasome system,UPS)降解途径来调控。Rho A(Ras homolog gene family member A,Rho A)是Rho小G蛋白家族成员,其功能涉及细胞极性、细胞迁移、细胞周期调控、神经系统发育等,通过UPS途径对该蛋白在细胞内的含量进行调控,可保证细胞的相关正常生理功能。在Rho A泛素化降解过程中,不同的泛素连接酶(ubiquintin ligases,E3)发挥了重要的作用。该文将简单介绍UPS的过程和Rho A蛋白质的结构、功能,详细论述Rho A泛素化降解过程的分子机制和生物学功能。

The GTP-binding active form and GDP-binding inactive form can be transformed each other by RhoG （Rho small GTPases） family. And RhoG acts as the molecular switches to regulate multiple celullar processes, the cellular RhoG can be degradedby UPS （ubiquitin-proteasome system）. RhoA is a classical member of Rho small GTPases, which plays important roles in controlling cell polarity, migration, cell cycle and nervous system development. The UPS mediated regulations ofRhoA ubiquitination guarantee the normal cellular function. Distinct E3 types play an important role during the UPS mediated degradation of RhoA. This review will give an outline of the UPS and the structure and function of RhoA, summarize the current understanding about the molecular mechanisms and physiological functions of UPS-mediated RhoA degradation.