UBXN1 is an adaptor protein linking ubiquitin-proteasome and ERAD pathways. Whether magnesium (Mg²⁺) supplementation modulates its protein interactome in pulmonary hypertension remains unclear. This IP-MS study mapped UBXN1-binding proteins in rat pulmonary artery tissues from MCT-induced pulmonary hypertension models with or without Mg²⁺ supplementation. Endogenous UBXN1 was immunoprecipitated from tissue lysates  using specific antibody, followed by SDS-PAGE, in-gel tryptic digestion, and LC-MS/MS on a Q-Exactive HF.