RNF7 (ring finger protein 7), also known as SAG, RBX2, and ROC2, is a RING-box E3 ubiquitin ligase that functions as a core component of cullin-RING ligase (CRL) complexes mediating ubiquitin-dependent protein degradation. In addition to its canonical ligase activity, RNF7 possesses intrinsic antioxidant capacity, scavenging reactive oxygen species through disulfide bond formation. RNF7 regulates diverse cellular processes including cell-cycle progression, apoptosis, and mitochondrial quality control. Following HIV-1 infection, RNF7 is hijacked as part of a cullin-5-RING complex to mediate APOBEC3F and APOBEC3G degradation. Beyond viral pathogenesis, RNF7 controls multiple oncogenic pathways: in prostate cancer, elevated RNF7 expression promotes p27 degradation and cell proliferation in an N6-methyladenosine-dependent manner, and treatment with the neddylation inhibitor MLN4924 suppresses this pathway 1. In renal cell carcinoma, RNF7 overexpression activates JAK/STAT3 signaling by ubiquitinating SOCS1, reducing sunitinib sensitivity 2. In glioma, RNF7 expression correlates with radiation resistance through maintenance of redox balance, particularly in IDH1-mutant tumors 3. Conversely, RNF7 ablation enhances natural killer cell anti-tumor immunity by preventing IL-15 receptor degradation 4, and loss of RNF7 in cardiac tissue causes mitochondrial dysfunction and heart failure 5. RNF7 is upregulated in inclusion body myositis, where it associates with protein aggregates and myofiber degeneration 6, and genetic variants confer cirrhosis risk in Eastern European populations 7.