Authors: Teng Ma, Xiao Tian, Baoding Zhang, Mengqi Li, Yu Wang, Chunyan Yang, Jianfeng Wu, Xiaoyan Wei, Qi Qu, Yaxin Yu, Shating Long, Jin-Wei Feng, Chun Li, Cixiong Zhang, Changchuan Xie, Yaying Wu, Zheni Xu, Junjie Chen, Yong Yu, Xi Huang, Ying He, Luming Yao, Lei Zhang, Mingxia Zhu, Wen Wang, Zhi-Chao Wang, Mingliang Zhang, Yuqian Bao, Weiping Jia, Shu-Yong Lin, Zhiyun Ye, Hai-Long Piao, Xianming Deng, Chen-Song Zhang, Sheng-Cai Lin
Published: 2022-02-23
DOI: 10.1038/s41586-022-04431-8
Source: Full article
AbstractMetformin, the most prescribed antidiabetic medicine, has shown other benefits such as anti-ageing and anticancer effects1–4. For clinical doses of metformin, AMP-activated protein kinase (AMPK) has a major role in its mechanism of action4,5; however, the direct molecular target of metformin remains unknown. Here we show that clinically relevant concentrations of metformin inhibit the lysosomal proton pump v-ATPase, which is a central node for AMPK activation following glucose starvation6. We synthesize a photoactive metformin probe and identify PEN2, a subunit of γ-secretase7, as a binding partner of metformin with a dissociation constant at micromolar levels. Metformin-bound PEN2 forms a complex with ATP6AP1, a subunit of the v-ATPase8, which leads to the inhibition of v-ATPase and the activation of AMPK without effects on cellular AMP levels. Knockout of PEN2 or re-introduction of a PEN2 mutant that does not bind ATP6AP1 blunts AMPK activation. In vivo, liver-specific knockout of Pen2 abolishes metformin-mediated reduction of hepatic fat content, whereas intestine-specific knockout of Pen2 impairs its glucose-lowering effects. Furthermore, knockdown of pen-2 in Caenorhabditis elegans abrogates metformin-induced extension of lifespan. Together, these findings reveal that metformin binds PEN2 and initiates a signalling route that intersects, through ATP6AP1, the lysosomal glucose-sensing pathway for AMPK activation. This ensures that metformin exerts its therapeutic benefits in patients without substantial adverse effects.