Fig. 5: Skp2 regulation of the Akt/Wee1 signaling axis is required for the maintenance of Survivin stabilization.

A Skp2-deficient OSCC cells were treated with/without IR and subsequently analyzed by IB. B Akt ubiquitination was detected by Ni-NTA Pull-down assay. C Flag-Skp2 WT or C18A mutants and His-Ub were transfected into OSCC cells for 48 h followed by Ni-NTA Pull-down experiment. D IB assay for the effect of IR on the Akt/Wee1 signaling axis in Skp2 deficient cells. E IB assay of the Akt inhibitor (MK2206 5 μM) on the Akt/Wee1 signaling axis in CAL27 cells. F IB analysis was performed in Skp2-deficient CAL27 cells transfected with Mry-Akt1 plasmid for 48 h, followed by IR treatment for 24 h. WCE was prepared for IB analysis. G, H CAL27 cells were transfected with siCtrl, siFBXL7 (G) or siXIAP (H) for 24 h and treated with/without IR, followed by IB analysis. I Flag-Survivin-WT or T34D was transfected into CAL27 cells for 48 h. IR treatment was performed and cells were cultured for 24 h, MG132 was added to the culture medium for 6 h. The WCE was subjected to IB analysis. J IP assay to detect the ubiquitination of Survivin in OSCC cells after siFBXL7 transfection and IR treatment. K Co-Immunoprecipitation (Co-IP) was performed to detect the interaction between FBXL7 and Survivin in Skp2-deficient CAL27 cells.