PTEN and prostate cancer: To confirm the association between PTEN and spliceosomal proteins, cytoplasmic and nuclear proteins were extracted from 293T cells (Fig. 3d), MEF (Fig. 3e) or prostate cancer cell line DU145 cells (Supplementary Fig. 3B), and co-immunoprecipitations (co-IPs) with anti-PTEN antibody or non-specific IgG were performed, followed by immunoblotting with antibodies against some spliceosomal proteins.