E3 SUMO-protein ligase that modulates cell cycle progression and functions as a repressor of endocycle onset in meristems. May function downstream of the meristem patterning transcription factors PLETHORA 1 and 2 (PLT1 and PLT2) in root meristem development. Modulates the expression of the mitotic cyclins CYCB1-1 and CYCB1-2 and cyclin-dependent kinases CDKB1-1 and CDKB2-1 in root meristem. Involved in cytokinin signaling in root development. Protein modification; protein sumoylation. Interacts with SCE1. Sumoylated, possibly via autosumoylation. Dwarf plants with short roots and defective meristems. Belongs to the NSE2 family.