Insulin Increases Sestrin 2 Content by Reducing Its Degradation through the PI₃K/mTOR Signaling Pathway

Figure 3

Insulin or the proteasomal inhibitor MG132 blocks SESN2 degradation. (a) HepG2 cells were pretreated with CHX for 30 min followed by a treatment with or without 100 nM of insulin (INS) for the indicated times. The cells were then lysed for SESN2 western blotting. Right panel is the plot of densitometric analysis. compared with noninsulin treatment. (b) and (c) HepG2 cells were treated with the indicated reagents for 30 min, followed by a treatment with or without 100 nM insulin for 8 h. The cells were then lysed for SESN2 western blotting. (d) HepG2 cells were incubated with or without insulin or MG132 for 18 h and the cells were lysed. Western blotting of SESN2 and β-actin (loading control) of total cellular proteins (left panel) or SESN2 immunoprecipitation followed by polyubiquitin antibody western blotting (right panel). IP indicates the immunoprecipitation antibody; IB indicates the immunoblotting antibody. Bottom panel of left panel: western blotting of the input samples. A representative blot of three independent experiments.

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