A molecular link between cell wall biosynthesis, translation fidelity, and stringent response in Streptococcus pneumoniae.
A molecular link between cell wall biosynthesis, translation fidelity, and stringent response in Streptococcus pneumoniae.
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DOI：
10.1073/pnas.2018089118
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发表时间：
2021-04-06
影响因子：
11.1
通讯作者：
Hiller NL
中科院分区：
文献类型：
--
作者：
Aggarwal SD;Lloyd AJ;Yerneni SS;Narciso AR;Shepherd J;Roper DI;Dowson CG;Filipe SR;Hiller NL
在感染期间，微生物必须在人类宿主的恶劣环境条件下存活。当暴露于压力时，细菌激活细胞内反应，称为严格反应途径，以确保其存活。这项研究将革兰氏阳性病原体中细胞生长的两个重要基本途径联系起来：它表明负责细胞壁生物合成的酶通过其改善蛋白质翻译错误的能力与严格响应途径相关联。我们的研究是在S.肺炎，其中MurM细胞壁生物合成酶，一种tRNA依赖性氨基酰基转移酶，与青霉素抗性有关。我们现在证明了MurM在翻译质量控制中的重要性，并确定它是严格反应途径的守门人。在人类宿主中生存需要细菌对不利条件做出反应。在重要的革兰氏阳性病原体肺炎链球菌（Streptococcus pneumoniae）中，细胞壁生物合成蛋白MurM和MurN是tRNA依赖性的氨基酰基转移酶，其导致分支的胞肽的产生。我们证明，野生型细胞在轻度酸性胁迫条件下经历最佳生长，但ΔmurMN菌株显示生长停滞和广泛溶解。此外，这些应激条件损害丙氨酰-tRNAAla合成酶可避免tRNAAla与丝氨酸的非同源错装的效率，这对细胞是有毒的。观察到的生长缺陷通过抑制严格的反应途径或通过过表达丙氨酰-tRNAAla合成酶的编辑结构域来挽救，所述编辑结构域能够使tRNA错酰化解毒。此外，MurM可以将来自错电荷的Seryl-tRNAAlaUGC的丝氨酰基团以精确的特异性掺入细胞壁前体中。我们的结论是，MurM有助于翻译控制的保真度和调节应激反应，减少池的错误的tRNA。最后，我们表明，增强溶解ΔmurMN肺炎球菌是由LytA，和murMN操纵子影响巨噬细胞吞噬作用的LytA依赖的方式。因此，MurMN减弱应激反应，导致宿主-病原体相互作用。我们的数据表明，错氨酰化的tRNA积累和激活的严格的反应之间的因果关系。为了防止翻译的潜在破坏，MurM消耗seryl-tRNAAla可能是第一道防线。当这种机制被淹没或不存在时（ΔmurMN），严格的反应会关闭翻译，以避免错误翻译/错误折叠蛋白质的毒性产生。
During infection, microbes must survive the hostile environmental conditions of the human host. When exposed to stresses, bacteria activate an intracellular response, known as the stringent response pathway, to ensure their survival. This study connects two fundamental pathways important for cellular growth in a Gram-positive pathogen: it demonstrates that enzymes responsible for cell wall biosynthesis are connected to the stringent response pathway via their ability to ameliorate errors in protein translation. Our study was performed on S. pneumoniae, where the MurM cell wall biosynthesis enzyme, a tRNA-dependent amino acyl transferase, is linked to penicillin resistance. We now demonstrate the importance of MurM in translation quality control and establish that it serves as a gatekeeper of the stringent response pathway. Survival in the human host requires bacteria to respond to unfavorable conditions. In the important Gram-positive pathogen Streptococcus pneumoniae, cell wall biosynthesis proteins MurM and MurN are tRNA-dependent amino acyl transferases which lead to the production of branched muropeptides. We demonstrate that wild-type cells experience optimal growth under mildly acidic stressed conditions, but ΔmurMN strain displays growth arrest and extensive lysis. Furthermore, these stress conditions compromise the efficiency with which alanyl-tRNAAla synthetase can avoid noncognate mischarging of tRNAAla with serine, which is toxic to cells. The observed growth defects are rescued by inhibition of the stringent response pathway or by overexpression of the editing domain of alanyl-tRNAAla synthetase that enables detoxification of tRNA misacylation. Furthermore, MurM can incorporate seryl groups from mischarged Seryl-tRNAAlaUGC into cell wall precursors with exquisite specificity. We conclude that MurM contributes to the fidelity of translation control and modulates the stress response by decreasing the pool of mischarged tRNAs. Finally, we show that enhanced lysis of ΔmurMN pneumococci is caused by LytA, and the murMN operon influences macrophage phagocytosis in a LytA-dependent manner. Thus, MurMN attenuates stress responses with consequences for host–pathogen interactions. Our data suggest a causal link between misaminoacylated tRNA accumulation and activation of the stringent response. In order to prevent potential corruption of translation, consumption of seryl-tRNAAla by MurM may represent a first line of defense. When this mechanism is overwhelmed or absent (ΔmurMN), the stringent response shuts down translation to avoid toxic generation of mistranslated/misfolded proteins.
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DOI：
10.1126/science.1174343
发表时间：
2009-08-07
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Guo M;Chong YE;Beebe K;Shapiro R;Yang XL;Schimmel P
通讯作者：
Schimmel P
DOI：
10.1073/pnas.1525206113
发表时间：
2016-02-23
影响因子：
11.1
作者：
Bullwinkle, Tammy J.;Ibba, Michael
通讯作者：
Ibba, Michael
影响因子：
3.7
作者：
Atkinson GC;Tenson T;Hauryliuk V
通讯作者：
Hauryliuk V
影响因子：
11.4
作者：
Beebe, K;de Pouplana, LR;Schimmel, P
通讯作者：
Schimmel, P
影响因子：
64.8
作者：
Beebe, Kirk;Mock, Marissa;Schimmel, Paul
通讯作者：
Schimmel, Paul