Akt2-dependent activation of Rac1 in mouse gastrocnemius muscle as detected by immunofluorescent microscopy of cross sections of gastrocnemius muscle.

(a) The expression vector for Myr-p110α, together with either one of two siRNA duplexes against mouse Akt2 (#1 and #2) and a mixture of NC siRNA duplexes, was introduced into gastrocnemius muscle of wild-type mice. Insulin (175.5 μg/kg body weight) was administered intravenously. Endogenous Rac1 and Akt2 were visualized by immunofluorescent staining with anti-Rac1 and anti-Akt2 antibodies, respectively. Myr-p110α was visualized by immunofluorescent staining with an anti-HA antibody. Activated Rac1 (Rac1·GTP) was visualized by immunofluorescent staining with an anti-V5 antibody after treatment with GST-POSH(251–489)-V5×3. Scale bar, 20 μm. (b) Activation of Rac1 shown in (a) was quantified. Gray, orange, and blue bars represent the treatment with NC, #1, and #2 siRNA duplexes, respectively. Data are shown as means ± S.E. (n = 6). *P < 0.001.