Possesses E3 ubiquitin-protein ligase in vitro. Acts as upstream modulator of jasmonate (JA) signaling in response to various stimuli, such as JA-inhibited root growth, JA-inductive gene expression, coronatine-mediated pathogen susceptibility, wound-stimulated expression of JA-responsive genes and wound-induced JA biosynthesis (PubMed:22898498). Controls fumonisin B1 (FB1)-triggered programmed cell death (PCD) by modulating the JA signaling pathway. May mediate salicylic acid (SA) suppression of JA signaling in FB1-induced responses (PubMed:25788731). May mediate the formation of 'Lys-48'-linked multiubiquitin chains. Mediates the polyubiquitination and subsequent proteasomal degradation of the target protein GRXS17 (PubMed:27497447). 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. Interacts with UBC30, GRXS17 and GLB3. Widely expressed. Repressed by the mycotoxin fumonisin B1. No visible phenotype under normal growth conditions. The double mutant plants rglg3 and rglg4 show decreased sensitivity to jasmonate.