Bordetella bronchiseptica dermonecrotizing toxin induces reorganization of actin stress fibers through deamidation of Gln-63 of the GTP-binding protein Rho
Bordetella bronchiseptica dermonecrotizing toxin induces reorganization of actin stress fibers through deamidation of Gln-63 of the GTP-binding protein Rho
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DOI：
10.1073/pnas.94.21.11623
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发表时间：
1997-10-14
影响因子：
11.1
通讯作者：
Matsuda, M
中科院分区：
文献类型：
--
作者：
Horiguchi, Y;Inoue, N;Matsuda, M
博德氏杆菌毒素在部分培养细胞中引起肌动蛋白应激纤维的聚集和局灶性黏附，并在电泳上引起gtp结合蛋白Rho的迁移性改变。我们试图阐明毒素作用于Rho的分子基础。毒素处理RhoA的氨基酸序列分析显示Gln-63脱酰胺为Glu。用Glu取代Gln-63位点诱变的RhoA在电泳上的迁移率发生了变化，这与毒素处理的RhoA没有区别。携带Glu-63的突变型RhoA和毒素处理的RhoA在鸟苷5'-[γ -硫]三磷酸结合活性方面与未处理的野生型RhoA没有显著差异，但GTP水解活性都比未处理的RhoA降低了10倍。C3H10T1/2细胞转染含有Glu-63突变体RhoA的cDNA后，与毒素处理的细胞相似，细胞内广泛形成肌动蛋白应激纤维。这些结果表明，毒素催化了Rho的Gln-63的脱酰胺，使其具有组成活性，导致肌动蛋白应激纤维的形成。
Bordetella dermonecrotizing toxin causes assembly of actin stress fibers and focal adhesions in some cultured cells and induces mobility shifts of the small GTP-binding protein Rho on electrophoresis. We attempted to clarify the molecular basis of the toxin action on Rho. Analysis of the amino acid sequence of toxin-treated RhoA revealed the deamidation of Gln-63 to Glu. The substitution of Glu for Gln-63 of RhoA by site-directed mutagenesis caused a mobility shift on electrophoresis, which was indistinguishable from that of the toxin-treated RhoA Neither mutant RhoA bearing Glu-63 nor toxin-treated RhoA significantly differed from untreated wild type RhoA in guanosine 5'-[gamma-thio] triphosphate binding activity but both showed a 10-fold reduction in GTP hydrolysis activity relative to untreated RhoA. C3H10T1/2 cells transfected with cDNA of the mutant RhoA bearing Glu-63 showed extensive formation of actin stress fibers similar to the toxin-treated cells. These results indicate that the toxin catalyzes deamidation of Gln-63 of Rho and renders it constitutively active, leading to formation of actin stress fibers.