Figure 2.

Inhibition of PI3K promotes net nuclear accumulation of FOXO1–GFP under control conditions but does not block the marked IGF1-induced net nuclear efflux of FOXO1–GFP. A, representative fluorescent images of FOXO1–GFP in skeletal muscle fibers under different conditions. The first column shows the fiber under transmitted light conditions and contains a 10-μm scale bar that applies to all images in the figure. Each row shows the same fiber at different times (top labels) during the experiment and illustrates a different experimental condition (right side labels). B, time course experiment analysis of FOXO1–GFP N/C levels (average of N/C values from images shown in A, plus others, normalized to the average N/C before compounds were added) in the presence or absence of select compounds. C, N/C (not normalized) at the 90-min time point for each condition. There were no added compounds in control (A, top row; B, solid black line). The PI3K inhibitor BKM120 was added at 15 min (A, second and fourth rows; B, dashed lines). IGF1 was added at 30 min (A, third and fourth rows; B, red lines). NS, not significant.