TORC1-dependent sumoylation of Rpc82 promotes RNA polymerase III assembly and activity
TORC1-dependent sumoylation of Rpc82 promotes RNA polymerase III assembly and activity
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DOI：
10.1073/pnas.1615093114
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发表时间：
2017-01-31
影响因子：
11.1
通讯作者：
Enserink, Jorrit M.
中科院分区：
文献类型：
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作者：
Chymkowitch, Pierre;Nguea, Aurelie;Enserink, Jorrit M.
在不断变化的营养条件下保持细胞动态平衡对所有生物体的生长和发育都是至关重要的。在失去营养供应时维持体内平衡的机制还不是很清楚。通过绘制酿酒酵母中的SUMO蛋白质组图，我们发现了一组主要参与转录的差异求和蛋白。RNA聚合酶III(RNAPIII)组分，包括RPC53、RPC82和Ret1，是特别突出的营养依赖相扑靶标。氮饥饿以及主营养反应调节靶标雷帕霉素复合体1(TORC1)的直接抑制导致这些蛋白质的快速脱氨基化，这反映在tRNA基因的相扑丢失上。依赖于TORC1的RPC82的总和基化是tRNA转录所必需的。从机制上讲，RPC82的总和基化对于RNAPIII全酶的组装和RPC82对tRNA基因的募集是重要的。综上所述，我们的数据表明，在最佳的生长条件下，RPC82的TORC1依赖的总合作用增强了RNAPIII的转录能力。
Maintaining cellular homeostasis under changing nutrient conditions is essential for the growth and development of all organisms. The mechanisms that maintain homeostasis upon loss of nutrient supply are not well understood. By mapping the SUMO proteome in Saccharomyces cerevisiae, we discovered a specific set of differentially sumoylated proteins mainly involved in transcription. RNA polymerase III (RNAPIII) components, including Rpc53, Rpc82, and Ret1, are particularly prominent nutrient-dependent SUMO targets. Nitrogen starvation, as well as direct inhibition of the master nutrient response regulator target of rapamycin complex 1 (TORC1), results in rapid desumoylation of these proteins, which is reflected by loss of SUMO at tRNA genes. TORC1-dependent sumoylation of Rpc82 in particular is required for robust tRNA transcription. Mechanistically, sumoylation of Rpc82 is important for assembly of the RNAPIII holoenzyme and recruitment of Rpc82 to tRNA genes. In conclusion, our data show that TORC1-dependent sumoylation of Rpc82 bolsters the transcriptional capacity of RNAPIII under optimal growth conditions.