E3 ubiquitin-protein ligase which is a component of the N-end rule pathway (PubMed:15548684, PubMed:20835242). Recognizes and binds to proteins bearing specific N-terminal residues that are destabilizing according to the N-end rule, leading to their ubiquitination and subsequent degradation (By similarity). Plays a critical role in chromatin inactivation and chromosome-wide transcriptional silencing during meiosis via ubiquitination of histone H2A (By similarity). Binds leucine and is a negative regulator of the leucine-mTOR signaling pathway, thereby controlling cell growth (PubMed:20298436). Required for spermatogenesis, promotes, with Tex19.1, SPO11-dependent recombination foci to accumulate and drive robust homologous chromosome synapsis (By similarity). Polyubiquitinates LINE-1 retrotransposon encoded, LIRE1, which induces degradation, inhibiting LINE-1 retrotransposon mobilization (By similarity). Catalyzes ubiquitination and degradation of the N-terminal part of NLRP1 following NLRP1 activation by pathogens and other damage-associated signals: ubiquitination promotes degradation of the N-terminal part and subsequent release of the cleaved C-terminal part of NLRP1, which polymerizes and forms the NLRP1 inflammasome followed by host cell pyroptosis (By similarity). 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. Interacts with UBE2B; promotes the UBE2B-H2A interaction and the ubiquitination of histone H2A by UBE2B and UBR2 (By similarity). Interacts with RECQL4 (PubMed:15317757, PubMed:20835242). Interacts with TEX19; does not lead to TEX19 degradation and stabilizes it (By similarity). Interacts with CASP8 (PubMed:28602583). Interacts with ATXN3 (PubMed:30455355). Interacts with UBE2O (By similarity). Associated with chromatin during meiosis. Broadly expressed, with highest levels in skeletal muscle, kidney and pancreas. Present in acinar cells of the pancreas (at protein level). Expressed in fetal pancreas. The RING-H2 zinc finger is an atypical RING finger with a His ligand in place of the fourth Cys of the classical motif. The UBR-type zinc finger forms a pocket that mediates recognition of type 1 N-degrons. It exhibits preference for Arginine in first position, has poor affinity for histidine, and doesn't bind acetylated peptides. Derived from mouse cDNA data. Belongs to the UBR1 family.