结节性硬化症复合物2(TSC2)N端赖氨酸乙酰化状态通过调节mTORC1信号传导和自噬来影响其稳定性。
TSC2 N-terminal lysine acetylation status affects to its stability modulating mTORC1 signaling and autophagy.
作者信息
García-Aguilar Ana, Guillén Carlos, Nellist Mark, Bartolomé Alberto, Benito Manuel
机构信息
Faculty of Pharmacy, Department of Biochemistry and Molecular Biology II, Complutense University of Madrid, Madrid 28040, Spain.
Faculty of Pharmacy, Department of Biochemistry and Molecular Biology II, Complutense University of Madrid, Madrid 28040, Spain; Spanish Biomedical Research Center in Diabetes and associated metabolic disorders (CIBERDEM), Instituto de Salud Carlos III, Spain.
出版信息
Biochim Biophys Acta. 2016 Nov;1863(11):2658-2667. doi: 10.1016/j.bbamcr.2016.08.006. Epub 2016 Aug 16.
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 5mM (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 K106Q mutant, 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.
越来越多的证据表明蛋白质乙酰化在控制新陈代谢的不同过程中发挥作用。沉默调节蛋白(烟酰胺腺嘌呤二核苷酸依赖性组蛋白脱乙酰酶)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物(TSC2)赖氨酸乙酰化在mTORC1信号激活、自噬和细胞增殖调控中的作用。5mM烟酰胺(一种常用于抑制SIRT1的浓度)增加了TSC2 N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mTORC1激活和细胞增殖。相反,白藜芦醇(RESV)作为沉默调节蛋白去乙酰化活性的激活剂,可避免TSC2乙酰化,抑制mTORC1信号并促进自噬。此外,去乙酰化状态的TSC2可防止泛素化。使用MEF Sirt1 +/+和Sirt1 -/-细胞或MIN6细胞中的SIRT1抑制剂(EX527),TSC2发生了高乙酰化,烟酰胺和白藜芦醇均无法调节mTORC1信号。然后,在MIN6细胞或MEF Tsc2-/-细胞中沉默Tsc2,烟酰胺或白藜芦醇对SIRT1的调节对mTORC1信号的影响被消除。我们还观察到,源自结节性硬化症患者的TSC2 N端结构域中的两个赖氨酸突变体对mTORC1信号有不同的调节作用。TSC2 K599M变体的mTORC1活性较低。然而,对于K106Q突变体,在基础状态以及对烟酰胺的反应中,mTORC1信号均被激活。本研究首次揭示了TSC2赖氨酸乙酰化状态与其稳定性之间的关系,代表了一种调节mTORC1通路的新机制。