UBE2Z (ubiquitin conjugating enzyme E2 Z) is a ubiquitin-conjugating enzyme that catalyzes the covalent attachment of ubiquitin to target proteins as part of the ubiquitin-proteasome system 1. The enzyme is widely expressed in human tissues, with highest levels in placenta, pancreas, spleen, and testis, and localizes to both nucleus and cytoplasm 1. UBE2Z functions specifically with the E1 enzyme UBA6 rather than UBE1, and works in conjunction with E3 ligases such as FBXW7 to facilitate protein degradation 2. The enzyme plays important roles in cellular stress responses, including endoplasmic reticulum stress-associated protein degradation and tight junction regulation in airway epithelial cells exposed to IL-13 32. Clinically, UBE2Z demonstrates significant disease relevance as it is upregulated in multiple cancers including hepatocellular carcinoma and lung adenocarcinoma, where high expression correlates with poor prognosis, advanced tumor stage, and aggressive cellular behaviors 45. UBE2Z knockdown reduces cancer cell viability, migration, and invasion while affecting epithelial-mesenchymal transition markers 45. Additionally, UBE2Z autoantibodies serve as potential biomarkers for hepatitis B-related hepatocellular carcinoma and immune-related adverse events in melanoma immunotherapy 67.