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 (PubMed:27497447). Binds to and coactivates GAF1/IDD2 and ENY/IDD1 (PubMed:25035403). Widely expressed. Induced by the mycotoxin fumonisin B1. No visible phenotype under normal growth conditions. The double mutant plants rglg3 and rglg4 show decreased sensitivity to jasmonate.