Resveratrol-induced Sirt1 phosphorylation by LKB1 mediates mitochondrial metabolism

Yuanyuan Huang,Jianlin Lu,Li Zhan,Ming Wang,Ronghua Shi,Xiao Yuan,Xinjiao Gao,Xing Liu,Jianye Zang,Wei Liu,Xuebiao Yao

doi:10.1016/j.jbc.2021.100929

Abstract

The NAD+-dependent deacetylase Sirt1 has been implicated in the prevention of many age-related diseases, including cancer, type 2 diabetes, and cardiovascular disease. Resveratrol, a plant polyphenol, exhibits antiaging, antitumor, and vascular protection effects by activating Sirt1. However, the molecular mechanism of Sirt1 activation as induced by resveratrol remains unclear. By knockdown/rescue experiments, fluorometric Sirt1 activity assay, immunoprecipitation, and pull-down assays, we identify here that the tumor suppressor LKB1 (liver kinase B1) as a direct activator of Sirt1 elicited by resveratrol. Resveratrol promotes the binding between LKB1 and Sirt1, which we first reported, and this binding leads to LKB1-mediated phosphorylation of Sirt1 at three different serine residues in the C terminus of Sirt1. Mechanistically, LKB1-mediated phosphorylation increases intramolecular interactions in Sirt1, such as the binding of the C terminus to the deacetylase core domain, thereby eliminating DBC1 (Deleted in Breast Cancer 1, Sirt1 endogenous inhibitor) inhibition and promoting Sirt1–substrate interaction. Functionally, LKB1-dependent Sirt1 activation increases mitochondrial biogenesis and respiration through deacetylation and activation of the transcriptional coactivator PGC-1α. These results identify Sirt1 as a context-dependent target of LKB1 and suggest that a resveratrol-stimulated LKB1-Sirt1 pathway plays a vital role in mitochondrial metabolism, a key physiological process that contributes to numerous age-related diseases.

Highlights

Been postulated that the activity of Sirt1 is modulated in response to multiple stresses, including genotoxicity, energetic stress, and oxidative stress [11]
liver kinase B1 (LKB1)-dependent phosphorylation is required for resveratrolinduced Sirt1 activation
Because all the three phosphorylation residues by LKB1 we identified are located in the C terminus, we postulated that phosphorylation at these sites may affect the interaction between the essential for Sirt1 activity (ESA) region and the core domain

Summary

Introduction

Been postulated that the activity of Sirt1 is modulated in response to multiple stresses, including genotoxicity, energetic stress, and oxidative stress [11]. Followed in vitro deacetylation assay with purified K382ac p53 peptide indicated that LKB1-directed phosphorylation is essential for Sirt1 deacetylase activity (Fig. 2B). When in vitro kinase assay demonstrated that Sirt1-3A mutant could not be phosphorylated by LKB1, it showed much weakened phosphorylation in resveratrol-treated cells (Fig. 2D, Fig. S2, F and G).

Results

Conclusion