Required for the function of some acidic activation domains, which activate transcription from a distant site. Binds double-stranded DNA. Binds dinucleosomes, probably at the linker region between neighboring nucleosomes. Plays a role in chromatin remodeling. Interacts with Gcn5 and Ada3 as part of a GCN5-containing ADA multiprotein complex (PubMed:12482983). Associated with a SAGA-type complex that also contains Taf5, e(y)1/Taf9, Taf10, Spt3 and Taf1 (PubMed:12697829). Expressed both maternally and zygotically throughout development.