MATR3 and alveolar soft part sarcoma: Immunoprecipitation (IP) for AT3 or control IgG in nuclear extracts from FU-UR-1 cells (human RCC cell line driven by AT3.2) and mouse ASPS tumors demonstrated similar interaction profiles between the species by mass spectrometry-based proteomics, with VCP, MATR3, and MTA2 showing the strongest protein associations (Fig. 1a, Supplementary Fig. 1a).