UBR2 is an E3 ubiquitin ligase functioning as a component of the N-end rule pathway, recognizing proteins bearing destabilizing N-terminal residues (N-degrons) and marking them for ubiquitin-dependent proteasomal degradation 1. UBR2 recognizes both type-1 N-degrons (positively charged residues) and type-2 N-degrons (bulky hydrophobic residues), with activity regulated by N-terminal acetylation status. Beyond canonical N-degron recognition, UBR2 exhibits diverse cellular functions: it negatively regulates mTOR signaling through leucine binding, controlling cell growth 2, and positively regulates T-cell receptor signaling by catalyzing Lys63-linked ubiquitination of the kinase Lck, promoting inflammatory responses 3. UBR2 is dysregulated in disease contexts. In primary ovarian insufficiency, UBR2 mutations impair meiotic processes critical for fertility 4. In pancreatic cancer cachexia, UBR2 induction in muscle tissue promotes myofibrillar protein degradation and muscle wasting 5. Conversely, constitutively active UBR2 ameliorates hepatic steatosis by degrading lipid droplet proteins 6. UBR2 function is tightly controlled: DUSP22 phosphatase inactivates UBR2 through Lys48-linked ubiquitination, dampening inflammation 3. Complete loss of both UBR1 and UBR2 causes embryonic lethality with neurogenesis and cardiovascular defects 7, indicating essential roles in development.