Targeted functional analysis of p300 coactivator in Wnt/β-catenin signaling pathway using phosphoproteomic and biochemical approaches

► The p300/β-catenin interaction was increased by culturing cells in DM medium. ► Serine 12 of p300 was identified as a novel phosphorylation site. ► The phosphorylation at Serine 12 mediates the binding of p300 with β-catenin. ► The p38 MAPK activation is required for the Serine 12 phosphorylation.