Phosphoproteomics Reveals AMPK Substrate Network in Response to DNA Damage and Histone Acetylation.

Abstract AMP-activated protein kinase (AMPK) is a conservative energy sensor that plays roles in diverse biologic processes via direct phosphorylation on various substrates. Emerging studies have demonstrated the regulatory roles of AMPK in DNA repair, but the underlying mechanisms remain to be fully understood. Herein, using mass spectrometry-based proteomic technologies, we systematically investigate the regulatory network of AMPK in DNA damage response (DDR). Our system-wide phosphoproteome study uncovers a variety of newly-identified potential substrates involved in diverse biologic processes, whereas our system-wide histone modification analysis reveals a linkage between AMPK and histone acetylation. Together with these findings, we discover that AMPK promotes apoptosis by phosphorylating apoptosis-stimulating of p53 protein 2 (ASPP2) in irradiation (IR)-dependent way and regulates histone acetylation by phosphorylating histone deacetylase 9 (HDAC9) in IR-independent way. Besides, we reveal that disturbing the histone acetylation by the bromodomain BRD4 inhibitor JQ-1 enhances the sensitivity of AMPK-deficient cells to IR. Therefore, our studies provided a source to study the phosphorylation and histone acetylation underlying the regulatory network of AMPK, which could be beneficial to understand the exact role of AMPK in DDR.