PSMG1 (proteasome assembly chaperone 1) is a molecular chaperone that promotes assembly of the 20S proteasome core complex. The protein functions as part of a heterodimer with PSMG2, binding specifically to PSMA5 and PSMA7 proteasome subunits to facilitate assembly of the heteroheptameric alpha ring while preventing inappropriate alpha ring dimerization. PSMG1 is involved in protein folding and chaperone-mediated protein complex assembly processes within the cytoplasm, nucleus, and other cellular compartments. Disease-wise, PSMG1 shows significant genetic associations with inflammatory conditions and cancer. Polymorphisms in PSMG1, particularly rs4816648, are associated with both susceptibility and severity of ankylosing spondylitis in Chinese populations 1. The gene also contributes to pediatric inflammatory bowel disease susceptibility through gene-gene interactions with TLR4, TNFRSF6B, and IRGM 2. In cancer biology, PSMG1 functions as a tumor suppressor target of oncogenic miR-484 in prostate cancer, where its downregulation promotes cancer cell mobility 3. Additionally, PSMG1 is located on chromosome 21 and shows altered expression in trisomy 21 conditions, suggesting potential roles in Down syndrome pathogenesis 4. The gene's involvement in neurodevelopmental disorders has also been identified through network analyses 5.