Has E3 ubiquitin-protein ligase activity. In the absence of an external substrate, it can catalyze self-ubiquitination. Acts as a scaffold protein that contributes to the effective activation of the JNK signaling pathway (By similarity). Plays an essential role in the anterior neural development. 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. Expressed both maternally and zygotically throughout early development. Becomes visible in the animal hemisphere of the embryo during the cleavage and blastula stages. At the gastrula stages, expressed broadly throughout the marginal zone and animal pole tissues. At the neurula stages, it shows the restricted expression in dorsal tissue. At later stages, expressed in the cement gland, brain, somite, notochord and pronephros. The RING finger domain is required for ubiquitin ligase activity and autoubiquitination. Autoubiquitinated. Ubiquitinated by SH3RF2, leading to proteasome-mediated degradation. Belongs to the SH3RF family.