Required for the function of some acidic activation domains, which activate transcription from a distant site (By similarity). The exact mechanism of action is not yet known (By similarity). ADA2 and GCN5 function to acetylate nucleosomes, opening up the promoter region (PubMed:28487409). The ADA2-GCN5 histone acetyltransferase (HAT) module is recruited by WOX11 to regulate crown root cell proliferation and stem cell maintenance of root meristem (PubMed:28487409). The ADA2-GCN5 HAT module together with WOX11 targets and regulates a set of root-specific genes involved in carbon metabolism, cell wall biosynthesis, and auxin transport and response (PubMed:28487409). Interacts with GCN5 and WOX11 (via N-terminus). Expressed in roots, mature leaves, stems and panicles.