Transcription factor that establishes leaf shape by repressing growth in specific subdomains of the leaf. Negatively regulates knox homeobox gene KNAT1/BP expression. May form heterodimeric complexes with TALE/KNOX proteins (By similarity). Interacts with OFP1, OFP2 and OFP5 (PubMed:15781858). Interacts with KNATM, isoform KNATM-B (PubMed:18398054). Expressed in lateral organs. The SR/KY and BELL domains are responsive for the interaction between the TALE/BELL proteins and the TALE/KNOX proteins. Belongs to the TALE/BELL homeobox family. Truncated N-terminus.