Phosphorylation of TET2 by AMPK is indispensable in myogenic differentiation [MeDIP-seq]

TET-mediated oxidation of 5-mC participates in both passive and active DNA demethylation, which exerts a significant influence on diverse biological processes. Mass spectrometry has identified multiple phosphorylation sites of TET2. However, the functions of these phosphosites and their corresponding kinases are mostly unknown. Here we showed that AMP-activated protein kinase (AMPK) phosphorylates murine TET2 at the serine residue 97 (S97), enhances TET2 stability through promoting its binding to 14-3-3ß. AMPK ablation resulted in decreased global 5-hmC levels at the myotube stages, severe differentiation defects of C2C12 cells and, significantly, total loss of expression of Pax7. Genome-wide analyses revealed increased DNA methylation at genic and enhancer regions of AMPK-null myoblasts and myotubes. Using CRISPR/Cas9 technology, we showed that a novel enhancer, which is hypermethylated in AMPK-null cells, regulates Pax7 expression. The phospho-mimicking mutant, TET2-S97E, could partly rescue the differentiation defect in AMPK ablated C2C12 cells. Together, our data demonstrated that AMPK is a critical regulator of myogenesis, partly through phosphorylating TET2. Overall design: MeDIP sequencing of WT and AMPK-/- C2C12 cells at day 0 and day 8 of differentiation. Two clones of AMPK-/- cells were used and input DNA controls were included for all samples.