Fig. 5

HJURP promotes HCC cell growth by inducing p21 ubiquitination. a RT-qPCR analysis of p21 in HJURP knockdown and overexpressed HCC cell lines. GAPDH was selected as the internal control. b Scatter plots shows a negative correlation between HJURP and p21 at the mRNA level. c HJURP was positively correlated with SKP2 at the mRNA level. d and e HJURP decreased p21 stability. p21 was detected by western blot after cells incubated with CHX for the indicated times. f and g Relative amount of p21 protein expression in Huh7 and SMMC-7721 cells. The amounts of p21 were analyzed by ImageJ. h Following the increase in HJURP expression, p21 exhibited a decreasing trend in the SMMC-7721 cells. i Western blot was performed in HCC-LM3 cells transfected with HJURP knockdown lentivirus and treated with DMSO or MG132. j Four E3 ubiquitin ligases (SKP2, CDC20, LRR1 and CDT2) were detected by western blot. k Depletion of HJURP attenuated p21 ubiquitination. SKP2 and LRR1 overexpression plasmids were transfected into HJURP knockdown cells. Cells were treated with MG132 (10 μM) for 5 h before being harvested. Immunoprecipitation was used for the detection of p21 degradation