Plays a pivotal role in the control of morphogenesis of shoot organs by negatively regulating the expression of boundary-specific genes such as CUC genes, probably through the induction of miRNA (e.g. miR164). In association with ABAP1, exerts a negative role in cell proliferation in leaves, possibly by inhibiting mitotic DNA replication. Participates in ovule develpment (PubMed:25378179). Forms a heterodimeric complex with ABAP1 (PubMed:18818695). Interacts with SPL (PubMed:25527103, PubMed:25378179). Expressed in cotyledons, particularly in the vascular region, in leaves, roots, stems, buds, flowers and siliques. Expressed during ovule development (PubMed:25378179).