Fig. 6

G0S2 activates mTOR-S6K signaling and thereby inhibits RNF168 expression and RNF168-mediated 53BP1 ubiquitination in response to IR. a WB analysis of p-S6K and RNF168 in U87 and LN229 cells with or without G0S2 overexpression. β-actin and S6K were used as controls. b Ectopic expression of RNF168 decreased 53BP1 protein expression upregulated by G0S2 overexpression at 8 h post-IR with 10 Gy, whereas it increased γ-H2AX expression inhibited by G0S2 overexpression. HA-RNF168 cDNA was transiently transfected into U87/G0S2 and LN229/G0S2 cells. c Representative images of 53BP1 staining at 8 h post-IR with 10 Gy. Cells were from b. Scale bars: 50 μm. d-e. Quantitative 53BP1 foci cells (d) and γ-H2AX foci cells (e) of c. Error bars, SD. *, p < 0.05. f RNF168 overexpression increased 53BP1 ubiquitination inhibited by G0S2 overexpression in response to IR. His-Ub and HA-RNF168 were transiently transfected into glioma U87/G0S2 and LN229/G0S2 cells. Data in (a, b and f) represent two to three independent experiments with similar results