TSC2 N-terminal lysine acetylation status affects to its stability modulating mTORC1 signaling and autophagy
TSC2 N-terminal lysine acetylation status affects to its stability modulating mTORC1 signaling and autophagy
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DOI：
10.1016/j.bbamcr.2016.08.006
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发表时间：
2016-11-01
影响因子：
5.1
通讯作者：
Benito, Manuel
中科院分区：
文献类型：
--
作者：
Garcia-Aguilar, Ana;Guillen, Carlos;Benito, Manuel
越来越多的证据表明，蛋白质乙酰化在控制代谢的不同过程中发挥着重要作用。Sirtuins（组蛋白脱乙酰基酶烟酰胺腺嘌呤二核苷酸依赖性）激活自噬，在细胞内稳态中起保护作用。本研究分析了结节性硬化症复合体（TSC 2）赖氨酸乙酰化，在调节mTORC 1信号激活，自噬和细胞增殖。烟酰胺5 mM（通常用于抑制SIRT 1的浓度），增加了TSC 2在其N-末端结构域的乙酰化，并伴随着其泛素化蛋白状态的增加，导致mTORC 1活化和细胞增殖。相反，白藜芦醇（RESV），sirtuins脱乙酰化活性的激活剂，避免TSC 2乙酰化，抑制mTORC 1信号传导和促进自噬。此外，TSC 2在其脱乙酰化状态下被阻止泛素化。使用MEF Sirt 1 +/+和Sirt 1-/-细胞或MIN 6细胞中的SIRT 1抑制剂（EX 527），TSC 2被过度乙酰化，NAM和RESV都无法调节mTORC 1信号传导。然后，在MIN 6或MEF Tsc 2-/-细胞中沉默Tsc 2，NAM或RESV对mTORC 1信号传导的SIRT 1调节的作用被消除。我们还观察到，两个TSC 2赖氨酸突变体在其N-末端结构域，来自TSC患者，差异调节mTORC 1信号。TSC 2 K599 M变体表现出较低的mTORC 1活性。然而，对于K106 Q突变体，在基础状态以及响应NAM时存在mTORC 1信号传导的激活。这项研究首次提供了TSC 2赖氨酸乙酰化状态与其稳定性之间的关系，代表了调节mTORC 1通路的新机制。(C)© 2016 Elsevier B. V.版权所有。
There is a growing evidence of the role of protein acetylation in different processes controlling metabolism. Sirtuins (histone deacetylases nicotinamide adenine dinucleotide-dependent) activate autophagy playing a protective role in cell homeostasis. This study analyzes tuberous sclerosis complex (TSC2) lysine acetylation, in the regulation of mTORC1 signaling activation, autophagy and cell proliferation. Nicotinamide 5 mM (a concentration commonly used to inhibit SIRT1), increased TSC2 acetylation in its N-terminal domain, and concomitantly with an augment in its ubiquitination protein status, leading to mTORC1 activation and cell proliferation. In contrast, resveratrol (RESV), an activator of sirtuins deacetylation activity, avoided TSC2 acetylation, inhibiting mTORC1 signaling and promoting autophagy. Moreover, TSC2 in its deacetylated state was prevented from ubiquitination. Using MEF Sirt1 +/+ and Sirt1 -/- cells or a SIRT1 inhibitor (EX527) in MIN6 cells, TSC2 was hyperacetylated and neither NAM nor RESV were capable to modulate mTORC1 signaling. Then, silencing Tsc2 in MIN6 or in MEF Tsc2 -/- cells, the effects of SIRT1 modulation by NAM or RESV on mTORC1 signaling were abolished. We also observed that two TSC2 lysine mutants in its N-terminal domain, derived from TSC patients, differentially modulate mTORC1 signaling. TSC2 K599M variant presented a lower mTORC1 activity. However, with K106Qmutant, there was an activation of mTORC1 signaling at the basal state as well as in response to NAM. This study provides, for the first time, a relationship between TSC2 lysine acetylation status and its stability, representing a novel mechanism for regulating mTORC1 pathway. (C) 2016 Elsevier B.V. All rights reserved.