β-adrenergic signaling-regulated MYPT1-PP1β phosphatase bridges chromatin states and actomyosin-tension-mediated YAP/TAZ transcriptional network for beige adipogenesis under cold stress

Protein kinase A phosphorylates proteins including histone H3 lysine 9 (H3K9) demethylase JMJD1A to facilitate beige adipogenesis upon β-adrenergic receptor (β-AR) activation, however, phosphatase(s) that antagonizes phosphorylation to inhibit beige adipogenesis is incompletely understood. Here we show that MYPT1-PP1β is a phosphatase that negatively regulates beige adipogenesis via dephosphorylation of pS265-JMJD1A and myosin regulatory light chain. Upon β-AR activation, MYPT1-PP1β is inhibited via T694 phosphorylation of MYPT1, facilitating phosphorylation of JMJD1A and beige adipogenesis under cold stress. Depletion of MYPT1-PP1β induces Ucp1 by orchestrating JMJD1A-mediated H3K9 demethylation and actomyosin-tension mediated YAP/TAZ activation. This induction of Ucp1 is abrogated in adipocytes expressing catalytically dead JMJD1A mutant, indicating that the coordinated epigenetic and transcriptional mechanisms are essential for beige adipogenesis. We also show that preadipocytes specific Mypt1 deficient mice exhibit higher cold tolerance with higher Ucp1 levels in subcutaneous white adipose tissues compared to control mice confirming its role at animal levels.