Kidney Protein Extraction and Western Blot

Protein extraction from the kidney cortex or cultured podocytes under different experimental conditions was conducted as previously described [22 (link)]. The nuclear protein is isolated and prepared as described in the Nuclear and Cytoplasmic Protein Extraction Kit (Nanjing KeyGEN Biotech, Nanjing, China). According to the manufacturer’s protocol, the protein concentration was evaluated using a protein assay reagent kit (Invitrogen, Thermo Fisher Scientific, Waltham, MA). Equal amount of proteins was separated on 9% sodium dodecyl sulfate–polyacrylamide gels and transferred onto polyvinylidene fluoride membranes (Millipore, Billerica, MA, USA). The membranes were blocked by 5% non-fat dry milk for 1 h at room temperature and then incubated overnight at 4 °C with the following primary antibodies: rabbit anti-ATF3 (Abcam, Cambridge, MA), rabbit anti-NFATc1(Abcam), rabbit anti-Histone (Cell Signaling Technology, Danvers, MA, USA), rabbit anti-Bax (Santa Cruz, Dallas, TX, USA), rabbit anti-Bcl-2 (Cell Signaling Technology), rabbit anti-GAPDH (Bioworld Technology, Nanjing, China), and rabbit anti-Histone (Cell Signaling Technology). Finally, membranes were detected using ECL Western Blotting Detection Reagents (Advansta, Menio Park, CA, USA).