Molecular Mechanism of Bacterial Persistence by HipA
Molecular Mechanism of Bacterial Persistence by HipA
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DOI：
10.1016/j.molcel.2013.08.045
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发表时间：
2013-10-24
期刊：
影响因子：
16
通讯作者：
Gerdes, Kenn
中科院分区：
文献类型：
--
作者：
Germain, Elsa;Castro-Roa, Daniel;Gerdes, Kenn
大肠杆菌的HipA是一种真核生物样丝氨酸-苏氨酸激酶，其抑制细胞生长并诱导持久性（多药耐受性）。以前，有人提出，HipA抑制细胞生长的磷酸化的基本翻译因子EF-Tu。在这里，我们提供的证据表明EF-Tu不是HipA的目标。相反，遗传筛选揭示了谷氨酰-tRNA合成酶（GltX）的过表达抑制了HipA的毒性。我们发现，HipA磷酸化保守的Ser（239）附近的活性中心的GItX和抑制氨酰化，一个独特的例子，氨酰-tRNA合成酶被抑制的毒素编码的毒素-抗毒素基因座。HipA仅磷酸化tRNA（Glu）结合的GItX，这与先前发现的含有Ser 239的调节基序在tRNA结合时改变构型一致。这些结果表明，HipA介导的持久性的产生“饥饿”密码子在核糖体A位点，触发（p）ppGpp的合成，一个假设，我们验证实验。
HipA of Escherichia coli is a eukaryote-like serine-threonine kinase that inhibits cell growth and induces persistence (multidrug tolerance). Previously, it was proposed that HipA inhibits cell growth by the phosphorylation of the essential translation factor EF-Tu. Here, we provide evidence that EF-Tu is not a target of HipA. Instead, a genetic screen reveals that the overexpression of glutamyl-tRNA synthetase (GltX) suppresses the toxicity of HipA. We show that HipA phosphorylates conserved Ser(239) near the active center of GItX and inhibits aminoacylation, a unique example of an aminoacyl-tRNA synthetase being inhibited by a toxin encoded by a toxin-antitoxin locus. HipA only phosphorylates tRNA(Glu)-bound GItX, which is consistent with the earlier finding that the regulatory motif containing Ser239 changes configuration upon tRNA binding. These results indicate that HipA mediates persistence by the generation of "hungry" codons at the ribosomal A site that trigger the synthesis of (p)ppGpp, a hypothesis that we verify experimentally.