FIGURE 5.

Arrb2 C terminus but not N terminus directly inactivates Akt. A, Arrb2 KO MEFs were transfected with Arrb2 full-length (FL) GFP vector or N- or C-terminal truncated Arrb2 GFP vectors or their GFP control vector. After 16 h of transfection, the cells were treated with SD for 6 h. The levels of total Akt, p-Akt, and GFP were determined by immunoblot. *, p < 0.05; **, p < 0.01. B, we transfected Arrb2 KO MEFs with Arrb2 full-length GFP vector or FLAG-Akt vector for 16 h. The cells were treated with SD for 6 h. Cell extracts were immunoprecipitated (IP)with anti-FLAG antibody and then analyzed together with cell lysates by immunoblotting (IB) with indicated primary antibodies. C, Arrb2 KO MEFs were transfected with C- or N-terminal truncated Arrb2 GFP vectors or FLAG-Akt vector. After 16 h of transfection, the cells were treated with SD for 6 h. Immunoprecipitates for Arrb2 C or N terminus and Akt were determined as in B. All of the results are representatives of three independent experiments.