FIGURE 2.

Metformin-stimulated cytosolic translocation of LKB1 and AMPK activation in C2C12 cells. A, time course of metformin-induced LKB1 translocation. Confocal microscopy images depict the localization of the Myc-tagged LKB1 (green, 2nd column), stained with Myc antibody, in C2C12 myoblasts treated with or without metformin (500 μm). The cell nuclei were stained with DAPI (blue, 1st column). Scale bar, 20 μm. B, quantification of cells with cytosolic LKB1 shown in A. The error bars represent mean ± S.E. from three independent experiments. ***, p < 0.001. C, time course for metformin-stimulated AMPK activation. After serum starvation, C2C12 myoblasts were treated with metformin (500 μm) as indicated. The Thr¹⁷² phosphorylation of AMPK (P-AMPK, 1st panel) and AMPK protein (2nd panel) levels were detected by Western blot analysis with specific antibodies.