E3 ubiquitin-protein ligase involved in the positive regulation of the gametogenesis progression. Mediates the proteasomal degradation of KRP6, a cyclin-dependent kinase inhibitor which accumulates during meiosis and blocks the progression of subsequent mitoses during gametophyte development. Functions in association with RHF2A (PubMed:18552199). Possesses E3 ubiquitin-protein ligase activity when associated with the E2 enzyme UBC8 in vitro (PubMed:15644464). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Interacts with KRP6. Expressed in stems, flowers, green siliques, cauline leaves, seeds and roots. Expressed in emerging floral primordia and then in stamens and carpels. Expressed first in stamen primordia, then in pollen mother cells and tapetal cells and later in microspores until flower stage 11. Expressed in carpels throughout flower development from primordia to the mature embryo sac stage. Expressed in developing embryo.