Masuda Minako, Minami Masayoshi, Shime Hiroaki, Matsuzawa Takeshi, Horiguchi Yasuhiko
Department of Bacterial Toxinology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
Infect Immun. 2002 Feb;70(2):998-1001. doi: 10.1128/IAI.70.2.998-1001.2002.
Bordetella dermonecrotic toxin (DNT) is known to activate the small GTPase Rho through deamidation or polyamination. In this study, we examined whether Rac and Cdc42, the two other members of the Rho family, serve as intracellular targets for the toxin. Immunoprecipitation and immunoblot assays revealed that DNT deamidated or polyaminated intracellular Rac and Cdc42. After the modifications, both Rac and Cdc42 lost their GTP-hydrolyzing, but not GTP-binding, activities. The interactions of the modified Rac and Cdc42 with their respective effectors were strictly dependent on GTP. MC3T3-E1 cells treated with DNT at high concentrations demonstrated extensive formations of lamellipodia and filopodia, which indicate the intracellular activation of Rac and Cdc42, respectively.
已知博德特氏菌皮肤坏死毒素(DNT)通过脱酰胺作用或多胺化作用激活小GTP酶Rho。在本研究中,我们检测了Rho家族的另外两个成员Rac和Cdc42是否作为该毒素的细胞内靶点。免疫沉淀和免疫印迹分析表明,DNT对细胞内的Rac和Cdc42进行了脱酰胺或多胺化修饰。修饰后,Rac和Cdc42均失去了GTP水解活性,但保留了GTP结合活性。修饰后的Rac和Cdc42与其各自效应器的相互作用严格依赖于GTP。用高浓度DNT处理的MC3T3-E1细胞显示出大量片状伪足和丝状伪足的形成,分别表明Rac和Cdc42在细胞内被激活。