JDP2 (Jun dimerization protein 2) is a multifunctional transcriptional regulator that primarily functions as a repressor of AP-1-mediated transcription through dimerization with Jun family proteins 1. The protein operates through multiple mechanisms: it directly binds histones and DNA, inhibiting p300-mediated histone acetylation and functioning as a histone chaperone to regulate chr14 assembly 2. JDP2 also recruits histone deacetylase 3 (HDAC3) to promoter regions for transcriptional repression. In disease contexts, JDP2 demonstrates tumor suppressor activity in hepatocellular carcinoma, where high expression correlates with smaller tumor size, early-stage disease, and better patient survival 1. The protein plays critical roles in cellular senescence by inhibiting polycomb repressive complex recruitment to the p16(Ink4a) promoter 2. JDP2 also functions in detoxification pathways as part of the AHR-NRF2-JDP2 gene battery, facilitating spatiotemporal transcriptional activation of detoxifying enzymes 34. Additionally, JDP2 regulates epithelial-mesenchymal transition by inhibiting EMT processes 5 and modulates TRAIL sensitivity through negative feedback regulation of the ATF4 pathway 6. Recent studies identified JDP2 as a regulator of T cell exhaustion, with its deletion enhancing tumor control and synergizing with immune checkpoint blockade 7.