E3 ubiquitin-protein ligase that acts as a regulator of the TORC1 signaling pathway (PubMed:35114100, PubMed:33594058). Positively regulates the TORC1 signaling pathway independently of arginine levels: acts by catalyzing 'Lys-29'-polyubiquitination and degradation of CASTOR1, releasing the GATOR2 complex from CASTOR1 (PubMed:33594058). Also negatively regulates the TORC1 signaling pathway in response to leucine deprivation: acts by mediating 'Lys-63'-linked polyubiquitination of SESN2, promoting SESN2-interaction with the GATOR2 complex (PubMed:35114100). Also involved in protein trafficking and localization (PubMed:23129617, PubMed:23353890, PubMed:24387786, PubMed:27808481, PubMed:32409562). Acts as a regulator of synaptic transmission by mediating ubiquitination and degradation of AMPAR receptor GluA2/GRIA2 (PubMed:23129617, PubMed:33650289). Does not catalyze ubiquitination of GluA1/GRIA1 (PubMed:23129617). Also acts as a regulator of the recycling endosome pathway by mediating ubiquitination of VAMP3 (PubMed:23353890). Regulates lysosome positioning by catalyzing ubiquitination and degradation of ARL8B (PubMed:27808481). Plays a role in growth regulation involved in G1/S transition by mediating, possibly by mediating ubiquitination of SLC22A18 (PubMed:16314844). Acts with a limited set of E2 enzymes, such as UBE2D1 and UBE2N (PubMed:33650289). 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. Targeted to cytoplasmic membranes; mainly localizes to lysosomal membrane (PubMed:16314844, PubMed:23129617). A subpopulation localizes to the cell membrane of neurons (PubMed:23129617). Widely expressed (PubMed:23129617). Strongly expressed in the kidney, pancreas, testis and liver (at protein level) (PubMed:16314844, PubMed:23129617). Autoubiquitinated in vitro in the presence of UBE2D1 and UBE2E1. Belongs to the Godzilla family.