Fig. 2

TRIM21 protects NPC cells from radiation-induced apoptosis by manipulating the GMPS–TP53 cascade. a Western blot detection of TP53 expression in HONE1 cells after radiation. b Co-immunoprecipitation using anti-FLAG antibody following western blot detection of USP7 and TP53 expression in GMPS–FLAG-overexpressing NPC cells with or without X-ray radiation. c GMPS expression in TRIM21-overexpressing NPC cells with or without X-ray radiation. d Co-immunoprecipitation using anti-MYC antibody following western blot detection of GMPS expression in TRIM21–MYC-overexpressing NPC cells with or without X-ray radiation. e Flow cytometry analysis of Annexin V and PI staining in HONE1 cells with TRIM21 GOF or LOF after X-ray radiation. Annexin⁺PI⁻ cells, which were in the early apoptotic stage, were evaluated and quantified. f, g Quantification of the apoptotic HONE1 f and 5-8F g cells. h, i Clonogenic survival assay of HONE1 cells with TRIM21 GOF h or LOF i. j Absorbance intensity of TRIM21 GOF and LOF tumor cells and their counterpart controls in mice (n = 5 for each group). The tumors were evaluated 2 and 3 weeks, respectively, after implantation, and the mice received radiotherapy (2 Gy daily and a total of 12 Gy) after 2 weeks. k, l The absorbance intensity analysis of tumors in mice. For the co-immunoprecipitation assay, the cells were pre-treated with MG132 to avoid GMPS degradation before harvesting. *P < 0.05, **P < 0.01, ***P < 0.001. Mu, mutant; ns, not significant; IP, immunoprecipitation