a, b Immunoblot analysis using the indicated antibodies was performed. The density of indicated proteins was normalized to tubulin (n = 4). *p < 0.05, **p < 0.01 (Student’s t test). c Immunoblot analysis using the indicated antibodies was performed after nuclear fractionation. The density of indicated nuclear proteins was normalized to lamin A/C (n = 4). *p < 0.05, **p < 0.01 (Student’s t test). d After transfection with the indicated siRNAs (50 pmol) for 48 h, immunoblot analysis using the indicated antibodies was performed. e After transfection with the indicated siRNAs (50 pmol) for 72 h, cells were pretreated with MG132, 5 μM for 1 h before harvest. Immunoblot analysis using the indicated antibodies was performed. f Relative mRNA levels in whole cell lysates were measured by real-time PCR. The mRNA levels were normalized to β-actin (n = 3). g, h After treating the indicated cells with MG132, 20 μM for 1 h or not (g), or bafilomycin A1 (Baf.A1), 1 μM for 2 h or not (h), immunoblot analysis using the indicated antibodies was performed.