RNF148 is an E3 ubiquitin ligase with restricted tissue expression and emerging roles in both reproductive and malignant processes. Primary function: RNF148 possesses E3 ubiquitin ligase activity through its RING finger domain 1, enabling ubiquitin-dependent protein degradation 2. Mechanism: RNF148 localizes to cytoplasmic and endomembrane compartments and mediates substrate degradation through direct protein-protein interactions. Specifically, RNF148 uses its protease-associated domain to bind CHAC2 and target it for ubiquitination-mediated degradation 2, with K102 identified as a critical ubiquitination residue on CHAC2 2. Expression regulation: RNF148 is predominantly expressed in testicular interstitial cells, with expression beginning at postnatal day 21 and peaking at day 25 in mice 1. Expression is regulated by histone deacetylases, with HDAC inhibitors increasing RNF148 promoter acetylation and mRNA expression 3. Disease relevance: RNF148 is upregulated in colorectal cancer tissues and functions as an oncogene, promoting cell proliferation and migration while inhibiting apoptosis and 5-FU sensitivity 2. Clinical significance: RNF148 serves as an independent prognostic biomarker correlating with colorectal cancer patient survival and clinicopathological parameters 2, suggesting potential therapeutic targeting.