Starvation sensing by mycobacterial RelA/SpoT homologue through constitutive surveillance of translation.
Starvation sensing by mycobacterial RelA/SpoT homologue through constitutive surveillance of translation.
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DOI：
10.1073/pnas.2302006120
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发表时间：
2023-05-30
影响因子：
11.1
通讯作者：
Ojha, Anil K.
中科院分区：
文献类型：
--
作者：
Li, Yunlong;Majumdar, Soneya;Treen, Ryan;Sharma, Manjuli R.;Corro, Jamie;Gamper, Howard B.;Manjari, Swati R.;Prusa, Jerome;Banavali, Nilesh K.;Stallings, Christina L.;Hou, Ya-Ming;Agrawal, Rajendra K.;Ojha, Anil K.
细菌通过激活 RelA/SpoT 同系物 (Rsh) 在营养饥饿下持续存在，Rsh 合成生长调节警报酮 ppGpp。 Rsh 在识别 A 位点具有脱酰基 tRNA 的翻译延伸复合物后被特异性激活。然而，目前还不清楚 Rsh 如何识别饥饿细菌细胞内的这种复合物。我们在此表明，在分枝杆菌中诱导核糖体冬眠的条件会导致细胞内 Rsh 的丢失，这意味着与翻译核糖体的关联对于 Rsh 的细胞内稳定性是必要的。通过对 Rsh 结合的 70S 翻译起始复合物的结构分析，我们在此提出分枝杆菌 Rsh 通过组成性监视在早期延伸阶段进入翻译周期的核糖体来识别 Rsh 激活核糖体复合物。脱酰化 tRNA 进入翻译核糖体后，RelA/SpoT 同源物 (Rsh) 的激活会诱导这种严格反应，从而导致营养饥饿的分枝杆菌持续存在。然而，Rsh 在体内识别此类核糖体的机制仍不清楚。在这里，我们发现诱导核糖体冬眠的条件会导致细胞内 Rsh 以 Clp 蛋白酶依赖性方式丢失。在使用 Rsh 突变阻止其与核糖体相互作用的非饥饿细胞中也观察到这种损失，表明 Rsh 与核糖体的关联对于 Rsh 稳定性很重要。翻译起始复合物中 Rsh 结合的 70S 核糖体的冷冻电镜结构揭示了 Rsh 的 ACT 结构域与核糖体 L7/L12 茎碱基成分之间未知的相互作用，表明 A 位 tRNA 的氨酰化状态在第一个延伸周期期间受到监视。总之，我们提出了一种 Rsh 激活的监视模型，该模型源于其与进入翻译周期的核糖体的组成性相互作用。
Bacteria persist under nutrient starvation by activating RelA/SpoT homolog (Rsh), which synthesizes a growth-regulating alarmone, ppGpp. Rsh is activated specifically upon recognizing a translation elongation complex with deacylated-tRNA at the A-site. It is however unclear how Rsh identifies such a complex inside the starving bacterial cell. We show here that conditions inducing ribosome hibernation in mycobacteria cause loss of intracellular Rsh, implying that association with translating ribosomes is necessary for intracellular stability of Rsh. Using structural analysis of Rsh-bound 70S translation initiation complex, we propose here that mycobacterial Rsh identifies a Rsh-activating ribosomal complex by constitutively surveilling the ribosome entering the translation cycle at the early elongation stage. The stringent response, which leads to persistence of nutrient-starved mycobacteria, is induced by activation of the RelA/SpoT homolog (Rsh) upon entry of a deacylated-tRNA in a translating ribosome. However, the mechanism by which Rsh identifies such ribosomes in vivo remains unclear. Here, we show that conditions inducing ribosome hibernation result in loss of intracellular Rsh in a Clp protease–dependent manner. This loss is also observed in nonstarved cells using mutations in Rsh that block its interaction with the ribosome, indicating that Rsh association with the ribosome is important for Rsh stability. The cryo-EM structure of the Rsh-bound 70S ribosome in a translation initiation complex reveals unknown interactions between the ACT domain of Rsh and components of the ribosomal L7/L12 stalk base, suggesting that the aminoacylation status of A-site tRNA is surveilled during the first cycle of elongation. Altogether, we propose a surveillance model of Rsh activation that originates from its constitutive interaction with the ribosomes entering the translation cycle.
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影响因子：
4.5
作者：
Gratani FL;Horvatek P;Geiger T;Borisova M;Mayer C;Grin I;Wagner S;Steinchen W;Bange G;Velic A;Maček B;Wolz C
通讯作者：
Wolz C
影响因子：
14.9
作者：
Arenz S;Abdelshahid M;Sohmen D;Payoe R;Starosta AL;Berninghausen O;Hauryliuk V;Beckmann R;Wilson DN
通讯作者：
Wilson DN
严格控制核糖体依赖性激活。
影响因子：
64.8
作者：
Brown A;Fernández IS;Gordiyenko Y;Ramakrishnan V
通讯作者：
Ramakrishnan V
影响因子：
3.7
作者：
Atkinson GC;Tenson T;Hauryliuk V
通讯作者：
Hauryliuk V
DOI：
10.1073/pnas.1524915113
发表时间：
2016-08-16
影响因子：
11.1
作者：
Hood, Rachel D.;Higgins, Sean A.;Savage, David F.
通讯作者：
Savage, David F.