Activation of Rho through a cross-link with polyamines catalyzed by Bordetella dermonecrotizing toxin
Activation of Rho through a cross-link with polyamines catalyzed by Bordetella dermonecrotizing toxin
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DOI：
10.1093/emboj/19.4.521
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发表时间：
2000-02-15
期刊：
影响因子：
11.4
通讯作者：
Horiguchi, Y
中科院分区：
文献类型：
--
作者：
Masuda, M;Betancourt, L;Horiguchi, Y
小的GTdR Rho，调节各种细胞功能，也作为细菌毒素的特异性底物。在这里，我们证明，波氏杆菌皮肤坏死毒素（DNT）催化交联的Rho与无处不在的多胺，如腐胺，亚精胺和精胺。质谱分析表明，交联发生在Gln 63，据报道，在不存在多胺的情况下，DNT会将其脱酰胺。Rad和Cdc 42，Rho家族GTP酶的其他成员，也被DNT多胺化。多胺化，如脱酰胺，显着降低GTdR活性的Rho，而不影响其GTP结合活性，表明多胺化的Rho作为一个组成型活性类似物的行为。此外，多胺连接的Rho，即使在GDP结合的形式，更有效地与其效应ROCK比脱酰胺Rho在GTP结合的形式，当显微注射到细胞中，诱导应力纤维的异常形成，从DNT处理的细胞中看到的那些无法区分。结果表明，多胺连接的Rho，转导信号下游ROCK在一个新的GTP-独立的方式，在DNT细胞毒性中起着重要的作用。
The small GTPase Rho, which regulates a variety of cell functions, also serves as a specific substrate for bacterial toxins. Here we demonstrate that Bordetella dermonecrotizing toxin (DNT) catalyzes cross-linking of Rho with ubiquitous polyamines such as putrescine, spermidine and spermine. Mass spectrometric analyses revealed that the cross-link occurred at Gln63, which had been reported to be deamidated by DNT in the absence of polyamines. Rad and Cdc42, other members of the Rho family GTPases, were also polyaminated by DNT. The polyamination, like the deamidation, markedly reduced the GTPase activity of Rho without affecting its GTP-binding activity, indicating that polyaminated Rho behaves as a constitutively active analog. Moreover, polyamine-linked Rho, even in the GDP-bound form, associated more effectively with its effector ROCK than deamidated Rho in the GTP-bound form and, when microinjected into cells, induced the anomalous formation of stress fibers indistinguishable from those seen in DNT-treated cells. The results imply that the polyamine-linked Rho, transducing signals to downstream ROCK in a novel GTP-independent manner; plays an important role in DNT cell toxicity.