Sequence-specific DNA-binding protein that interacts with enhancer elements to regulate transcription of selected genes (By similarity). Required for neuroblast and epidermal morphogenesis, perhaps acting in cooperation with transcription factor aptf-2 (PubMed:27176626). Binds DNA as a dimer. RNAi-mediated knockdown causes embryonic lethality and morphological defects in larva (PubMed:27176626). Embryonic lethality is exacerbated on the transcription factor aptf-2 mutant background (PubMed:27176626). Belongs to the AP-2 family.