Probable transcriptional activator that promotes early floral meristem identity (PubMed:7919989). Is required subsequently for the transition of an inflorescence meristem into a floral meristem (PubMed:1675158). Plays a central role in the specification of floral identity, particularly for the normal development of sepals and petals in the wild-type flower, by spatially controlling the expression domains of multiple floral organ identity genes (PubMed:1675158, PubMed:23034631). Acts as A class cadastral protein by repressing the C class floral homeotic gene AGAMOUS in association with other repressors like LEUNIG and SEUSS (PubMed:1675158). Directly represses AGAMOUS by recruiting the transcriptional corepressor TOPLESS and the histone deacetylase HDA19 (PubMed:23034631). It is also required during seed development (PubMed:1675158). May form homodimer. Interacts with HDA19 and with TPL in an EAR-motif dependent manner (PubMed:23034631). Sepals, petals, stamens, carpels, developing ovules, inflorescence stem, leaf and stem. It is detectable at low levels throughout the shoot apex and at enhanced levels in the inflorescence meristem, young floral buds and throughout the early stages of flower development and organogenesis. During floral organ differentiation it becomes spatially restricted to specific organ, tissue and cell types within the flower. Negatively regulated by the C class floral homeotic protein AGAMOUS in stamens and carpels. MicroRNA 172 (miRNA172) negatively regulates APETALA2 at the translational level and may modulate its expression pattern. Seems not to be influenced by jasmonate and Alternaria brassicicola. Mutations in the APETALA2 gene result in the ectopic expression of AGAMOUS, leading to the replacement of sepals by carpels and stamens and of petals by stamens. Belongs to the AP2/ERF transcription factor family. AP2 subfamily. Truncated N-terminus.