This project identifies GALNT1-interacting proteins in primary fibroblast-like synoviocytes (RASFs) derived from rheumatoid arthritis patients using co-immunoprecipitation (co-IP) coupled with mass spectrometry (MS). Briefly, RASF lysates were incubated with anti-GALNT1 antibody to capture GALNT1-associated protein complexes, and the immunoprecipitated proteins were analyzed by MS. Raw data were processed with Proteome Discoverer against the UniProt human proteome database for protein identification/quantification, with high-confidence hits filtered by PSM scores, sequence coverage, and fold enrichment vs. IgG controls.