Sf3b2

The total proteins were collected from cells using RIPA Lysis Buffer containing 1% phenylmethylsulphonyl fluoride (PMSF) (Beyotime, Shanghai, China), and the protein concentration was measured with a BCA protein assay Kit (Beyotime, Shanghai, China). Protein were denatured at 100 °C for 8 min with DualColor Protein Loading Buffer (Life, USA). The denatured proteins were separated on 10% sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and transferred onto PVDF membranes (Millipore, Billerica, MA, USA). The membranes were incubated for 20 min in quick blocking solution (Beyotime, Shanghai, China) at room temperature followed by incubation with primary monoclonal antibodies overnight at 4 °C with soft shaking. The primary antibodies against human p53, SF3B2, SF3B3, RBM17, Lamin-B1 and GAPDH were purchased from Proteintech Group (IL, USA). SCAP was purchased from Cell Signaling Technology (Danvers, MA 01,923, USA). CDK2/4/6, Cyclin D1, SF3A3, and p53 S46 were purchased from Abcam (Cambridge, MA, USA). And enhanced chemiluminescence reagent kit (Affinity Biosciences, Jiangsu, China) was utilized for exposure after the blot incubated with secondary antibody (Proteintech) for 1 h.

Cells were lysed in a buffer containing 100 mM Tris (pH 7.6), 1% Triton X-100, 150 mM NaCl, 0.1 mg aprotinin, 35 mg/ml PMSF 10 mM Na3VO4, 100 mM NaF, 10 mM Na4P2O7, and 4 mM EDTA (approximately 5 × 10⁶ cells). Samples were centrifuged at 4°C for 20 min to remove cell debris. Protein concentration was measured using the Bradford Assay (Bio-Rad). Laemmli buffer containing 100 mmol/L of dithiothreitol was added to the protein extracts and heated at 100°C for 5 min. Samples were run on a 10% SDS-PAGE. After the run, the proteins were transferred to nitrocellulose membranes (Millipore). Membranes were immunoblotted with NR4A3 (Abcam, ab41918), HnRNPK (Abcam, ab32969), SF3B2 (ProteinTech, 10919-1-AP), HnRNPA1 (ProteinTech, 11176-1-AP), PARP1 (Santa Cruz, sc-56197), Lamin B1 (Santa Cruz, sc-6127), and GAPDH (Santa Cruz, sc-32233) antibodies. K-562 protein samples were obtained from three independent experiments, all bands are shown in the Supplementary Material; however, only one patient sample of HSC CD34+ cells (which is a rare population of hematopoietic progenitors) was available for protein extraction. Band intensity was quantified using UVITEC alliance software.