Requirement of Mek1/2 activity for caAkt- or caKRas-mediated enhancement of TCR-induced mTOR signaling. (A) Establishment of Myr-Akt- and DD-Akt–expressing 2B4 cells was similar to the method described in Figure 4A except that retroviruses expressing Myr-Akt or DD-Akt were used. Akt expression in infected cells after sorting for GFP⁺ cells was determined by Western blot with an anti-Akt antibody. The blot was also probed with an anti–β-actin antibody for a loading control. (B-C) Akt-expressing 2B4 cells were not pretreated or pretreated with the indicated inhibitors, followed by anti-CD3 stimulation and immunoblot analysis as in Figure 4B. (D-E) Wt and caKRas-T (KRas) thymocytes were not pretreated or pretreated with the indicated inhibitors, followed by anti-CD3 stimulation and immunoblot analysis as in Figure 4B. Data shown are representative of/quantified from 3 experiments.