Takai Y, Kaibuchi K, Sasaki T, Tanaka K, Shirataki H, Nakanishi H
Department of Biochemistry, Kobe University School of Medicine, Japan.
Princess Takamatsu Symp. 1994;24:338-50.
The Rho family belongs to the Ras-related small GTP-binding protein (G protein) superfamily and regulates various cell functions in which the actomyosin system is involved, including cell morphology, membrane ruffling, cell motility, cell aggregation, cytokinesis, smooth muscle contraction, and yeast budding. Three GDP/GTP exchange proteins (GEPs), named Smg GDS, Dbl, and Rho GDI, and two GTPase activating proteins (GAPs), named Rho GAP and p190 associated with Ras GAP, have been identified. The Rho activity is likely to be regulated by protein kinase C which is linked through phospholipase C to the tyrosine kinase-type membrane receptors and the heterotrimeric G protein-linked receptors. It is likely that both Ras and Rho receive signals from the membrane receptors through different pathways and transduce signals to genes and cytoskeleton, respectively. In carcinogenesis, mutational activation of any component in the Ras signaling pathway may cause abnormal cell proliferation, whereas mutational activation of any component in the Rho signaling pathway may cause invasiveness and metastasis of carcinoma cells.
Rho家族属于Ras相关的小GTP结合蛋白（G蛋白）超家族，可调节涉及肌动球蛋白系统的各种细胞功能，包括细胞形态、膜褶皱、细胞运动、细胞聚集、胞质分裂、平滑肌收缩和酵母出芽。已鉴定出三种GDP/GTP交换蛋白（GEP），分别名为Smg GDS、Dbl和Rho GDI，以及两种GTP酶激活蛋白（GAP），分别名为Rho GAP和与Ras GAP相关的p190。Rho活性可能受蛋白激酶C调节，蛋白激酶C通过磷脂酶C与酪氨酸激酶型膜受体和异源三聚体G蛋白偶联受体相连。Ras和Rho可能都通过不同途径从膜受体接收信号，并分别将信号转导至基因和细胞骨架。在致癌过程中，Ras信号通路中任何成分的突变激活都可能导致细胞异常增殖，而Rho信号通路中任何成分的突变激活都可能导致癌细胞的侵袭和转移。
