DNAJC2 is a bifunctional DnaJ/Hsp40 chaperone protein with distinct cytosolic and nuclear roles 1. In the cytoplasm, DNAJC2 functions as a component of the ribosome-associated complex (RAC), stimulating ATPase activity of Hsp70 chaperones to facilitate cotranslational protein folding of nascent polypeptides 1. Nuclearly, DNAJC2 acts as a chr7 regulator that binds histone H2A ubiquitinated at lysine 119 and promotes displacement of polycomb repressive complex 1 (PRC1), thereby activating previously silenced genes 2. DNAJC2 demonstrates complex disease associations. In colorectal cancer, DNAJC2 is upregulated and promotes cell proliferation through AKT/P21 signaling, with expression correlating to tumor size 3. However, mutations in DNAJC2 are negatively associated with overall survival in lung adenocarcinoma patients 4. DNAJC2 expression increases in PD-1+ colon cancer cells treated with anti-PD-1 immunotherapy, potentially protecting tumors from chemotherapy 5. Additionally, DNAJC2 alterations show associations with Parkinson's disease 6 and appear in Alzheimer's disease plasma proteomes 7. The protein also contributes to developmental canalization, a buffering mechanism against environmental and genetic perturbations 8. These findings suggest DNAJC2 has pleiotropic functions in protein quality control and gene regulation with significant implications for cancer biology and neurodegeneration.