Fig. 3

Interactions between AURKA and AURKB protects them from degradation. a Representative confocal images of HEK293 cells co-transfected with AURKA-GFP (green) and AURKB-RFP (red). The merged images showed co-localization of AURKA and AURKB in the nuclei. (scale bars, 29 μm). b Co-IP and Western blotting analysis showed the interaction between endogenous AURKA and AURKB in U251 cells. c Nuclear and cytoplasmic proteins were extracted from U251 cells; IP and Western blotting analysis demonstrated interaction between endogenous AURKA and AURKB mainly in the nuclear fractions. d U251 cells were transfected with pEGFP-C1-SIX3. IP and Western blotting analysis showed that SIX3 did not affect the interaction between AURKA and AURKB but decreased the amount of interacting AURKA and AURKB. e, f U251 cells was transfected with siRNAs targeting AURKA. Twenty-four hours later, the U251 cells transfected with siRNAs were treated with MG132 (20 μM) for another 2 h. Western blotting analysis showed that MG132 treatment recovered AURKB protein level upon AURKA knockdown (e) and recovered AURKA protein level upon AURKB knockdown (f)