Plays an important role in organ size control. Acts as negative regulator of the anaphase-promoting complex/cyclosome (APC/C). Regulates cell proliferation during early development by targeting CYCA2-3 for APC/C-mediated degradation. Required for mitosis I during pollen microspore development. Interacts with CDC27B and CYCA2-3. Expressed in embryos, germinating seeds, hypocotyls and pollen grains. Growth-related phenotypes, such as formation of large roots, leaves and seeds, enlarged meristem size, and reduced fertility due to defect in male gametogenesis.