Phosphoproteomics Reveals Resveratrol-Dependent Inhibition of Akt/mTORC1/S6K1 Signaling

Resveratrol, a plant-derived polyphenol, regulates many cellular processes, including cell proliferation, aging and autophagy. However, the molecular mechanisms of resveratrol action in cells are not completely understood. Intriguingly, resveratrol treatment of cells growing in nutrient-rich conditions induces autophagy, while acute resveratrol treatment of cells in a serum-deprived state inhibits autophagy. In this study, we performed a phosphoproteomic analysis after applying resveratrol to serum-starved cells with the goal of identifying the acute signaling events initiated by resveratrol in a serum-deprived state. We determined that resveratrol in serum-starved conditions reduces the phosphorylation of several proteins belonging to the mTORC1 signaling pathway, most significantly, PRAS40 at T246 and S183. Under these same conditions, we also found that resveratrol altered the phosphorylation of several proteins involved in various biological processes, most notably transcriptional modulators, represented by p53, FOXA1, and AATF. Together these data provide a more comprehensive view of both the spectrum of phosphoproteins upon which resveratrol acts as well as the potential mechanisms by which it inhibits autophagy in serum-deprived cells.

白藜芦醇（Resveratrol）是一种植物来源的多酚类物质，可调控多种细胞进程，包括细胞增殖、衰老及自噬（autophagy）。然而，白藜芦醇在细胞内发挥作用的分子机制尚未完全阐明。值得注意的是，在营养丰富的培养条件下对细胞施加白藜芦醇处理可诱导自噬，而在血清剥夺状态下对细胞进行急性白藜芦醇处理则会抑制自噬。本研究中，我们对经白藜芦醇处理的血清饥饿细胞开展了磷酸化蛋白质组学分析，旨在明确白藜芦醇在血清剥夺状态下触发的急性信号事件。研究发现，在血清饥饿条件下，白藜芦醇可降低属于mTORC1信号通路的多种蛋白质的磷酸化水平，其中最为显著的是T246与S183位点上的PRAS40。在相同条件下，我们还观察到白藜芦醇改变了参与多种生物进程的多种蛋白质的磷酸化水平，其中最为突出的是以p53、FOXA1及AATF为代表的转录调控因子。综上，本研究数据更为全面地展现了白藜芦醇作用的磷酸化蛋白质谱，以及其在血清剥夺细胞中抑制自噬的潜在分子机制。