To explore whether the ubiquitination of other factors within the NCoR/SMRT complex may be affected by the lack of GPS2, possibly contributing to aberrant gene regulation in GPS2-KO cells, we explored the GPS2-regulated K63 ubiquitome that we recently characterized in mouse embryonic fibroblasts and breast cancer MDA-MB231 cells (35). This evidence concerns the gene GPS2 and breast carcinoma.