E3 ubiquitin-protein ligase required during early development (PubMed:19682089). E3 ubiquitin-protein ligases mediate ubiquitination of target proteins (PubMed:19682089). Required for epithelial integrity and midgut morphogenesis (PubMed:19682089). Associated component of the WMM complex, a complex that mediates N6-methyladenosine (m6A) methylation of RNAs, a modification that plays a role in the efficiency of mRNA splicing and RNA processing (PubMed:29535189). Its function in the WMM complex is unknown (PubMed:29535189). 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. Component of the WMM complex, a N6-methyltransferase complex composed of a catalytic subcomplex, named MAC, and of an associated subcomplex, named MACOM (PubMed:29535189). The MAC subcomplex is composed of Ime4/Mettl3 and Mettl14 (PubMed:29535189). The MACOM subcomplex is composed of fl(2)d, Flacc/Xio, Hakai, vir, and, in some cases of nito (PubMed:29535189). Interacts with shg/DE-cadherin (PubMed:19682089). High levels of maternal transcripts in blastoderm stage embryos are observed. Lethality during larval stages. Maternal mutants show a variety of defects in epithelial integrity, including stochastic loss of shg/DE-cadherin expression, as well as defects in cell specification and cell migration. Belongs to the Hakai family. The subcellular locations reported need confirmation (PubMed:19682089). Components of the WMM complex are known to localize in the nucleus, and it is also the case for the CBLL1/HAKAI protein in vertebrates. It is therefore likely that this protein mainly localizes in the nucleus.